![(a) HDRs of hydronium (black circles) and water (solid line) measured on the surface of a “hydronium-sandwich” ASW film, in which H3O+ and Cl– (produced by ionization of HCl) are initially trapped between the bottom H2O layer and the top D2O layer [D2O (~30 ML)/H+ + Cl–/H2O (≥110 ML)/Pt(111)]. The virtually identical HDRs for hydronium and water above ~150 K indicate efficient H/D exchange due to proton transfer. The broken line indicates the HDR of water molecules measured on the surface of a pure ASW film [D2O (~30 ML)/H2O (≥110 ML)/Pt(111)], where the H/D exchange reaction is not catalyzed by hydronium. (b) HDRs for hydroxide (black circle) and water (solid line) on the surface of a hydroxide-sandwich ASW film [D2O (~30 ML)/OH– + Na+/H2O (≥110 ML)/Pt(111)]. The HDR of hydroxide is significantly higher than that of water at 154–168 K owing to molecular hydroxide diffusion. The sample temperature was increased at a rate of 0.5 K s−1. The surface populations and isotopomeric compositions of hydroniums and hydroxides were measured by means of low-energy sputtering (LES). In this technique, ions present at the ice surface are desorbed by the collisions of Cs+ projectiles with the surface at low energy and the desorbed ions are detected by a mass spectrometer.9 The collision energy is controlled to be only slightly above the desorption threshold of the ions to minimize molecular fragmentation and suppress secondary ion emission. The isotopomeric composition of water molecules was measured by means of temperature-programmed desorption (TPD). Reproduced with permission from ref. 93. Copyright 2014 American Chemical Society](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_65_image_1.png "(a) HDRs of hydronium (black circles) and water (solid line) measured on the surface of a “hydronium-sandwich” ASW film, in which H3O+ and Cl– (produced by ionization of HCl) are initially trapped between the bottom H2O layer and the top D2O layer [D2O (~30 ML)/H+ + Cl–/H2O (≥110 ML)/Pt(111)]. The virtually identical HDRs for hydronium and water above ~150 K indicate efficient H/D exchange due to proton transfer. The broken line indicates the HDR of water molecules measured on the surface of a pure ASW film [D2O (~30 ML)/H2O (≥110 ML)/Pt(111)], where the H/D exchange reaction is not catalyzed by hydronium. (b) HDRs for hydroxide (black circle) and water (solid line) on the surface of a hydroxide-sandwich ASW film [D2O (~30 ML)/OH– + Na+/H2O (≥110 ML)/Pt(111)]. The HDR of hydroxide is significantly higher than that of water at 154–168 K owing to molecular hydroxide diffusion. The sample temperature was increased at a rate of 0.5 K s−1. The surface populations and isotopomeric compositions of hydroniums and hydroxides were measured by means of low-energy sputtering (LES). In this technique, ions present at the ice surface are desorbed by the collisions of Cs+ projectiles with the surface at low energy and the desorbed ions are detected by a mass spectrometer.9 The collision energy is controlled to be only slightly above the desorption threshold of the ions to minimize molecular fragmentation and suppress secondary ion emission. The isotopomeric composition of water molecules was measured by means of temperature-programmed desorption (TPD). Reproduced with permission from ref. 93. Copyright 2014 American Chemical Society")
![Results of TPD, LES, and RIS measurements for a “hydronium-sandwich” ice film [D2O (~70 ML)/H+ + Cl– (0.3 ML)/H2O (~120 ML)/Pt(111)] during an increase in the temperature from 138 to 178 K. The ordinate scale indicates the mass spectrometric signal intensity (count per second) for each experiment. (a) TPD curves of water isotopomers. (b) LES signals of various hydronium isotopomers appearing on the surface. (c) RIS measurement of water isotopomers on the surface. In RIS, Cs+ projectiles pick up molecules on the surface during the scattering process, and the resultant Cs+–molecule complex is identified by a mass spectrometer.9,106 The RIS signal is presented on a logarithmic scale. A roughing transition of the ice film occurred above ~173 K (shaded region), which destroyed the film structure.24,53-55 The TPD (a) and RIS (c) curves show changes in the isotopomeric composition of surface water molecules caused by diffusional mixing and H/D exchange reactions. The LES curves (b) indicate that hydroniums migrated from the film interior to the surface at a temperature above ~154 K. The temperature ramping rate was 0.5 degree s–1 for all the spectra. The Cs+ beam energy for the LES and RIS measurements was 35 eV. Reproduced with permission from ref. 99. Copyright 2012 American Chemical Society](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_66_image_1.png "Results of TPD, LES, and RIS measurements for a “hydronium-sandwich” ice film [D2O (~70 ML)/H+ + Cl– (0.3 ML)/H2O (~120 ML)/Pt(111)] during an increase in the temperature from 138 to 178 K. The ordinate scale indicates the mass spectrometric signal intensity (count per second) for each experiment. (a) TPD curves of water isotopomers. (b) LES signals of various hydronium isotopomers appearing on the surface. (c) RIS measurement of water isotopomers on the surface. In RIS, Cs+ projectiles pick up molecules on the surface during the scattering process, and the resultant Cs+–molecule complex is identified by a mass spectrometer.9,106 The RIS signal is presented on a logarithmic scale. A roughing transition of the ice film occurred above ~173 K (shaded region), which destroyed the film structure.24,53-55 The TPD (a) and RIS (c) curves show changes in the isotopomeric composition of surface water molecules caused by diffusional mixing and H/D exchange reactions. The LES curves (b) indicate that hydroniums migrated from the film interior to the surface at a temperature above ~154 K. The temperature ramping rate was 0.5 degree s–1 for all the spectra. The Cs+ beam energy for the LES and RIS measurements was 35 eV. Reproduced with permission from ref. 99. Copyright 2012 American Chemical Society")
![Maps of the drilling site, modified from Han et al. [40]. (a) The Styx Glacier in northern Victoria Land lies along the western margin of the Ross Sea. The sample locations of Udisti [45], Stenni et al. [38] and Kwak et al. [36] in (b) are marked for comparison. (c) The site where samples were collected, showing the various tents during the 2014–2015 summer expedition. GPR: ground-penetrating radar; AMOS: automatic meteorological observation system. (d) Investigation lines for ground penetrating radar (GPR). Details of the measurements and results will be presented in Figure 3](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_96_image_1.png "Maps of the drilling site, modified from Han et al. [40]. (a) The Styx Glacier in northern Victoria Land lies along the western margin of the Ross Sea. The sample locations of Udisti [45], Stenni et al. [38] and Kwak et al. [36] in (b) are marked for comparison. (c) The site where samples were collected, showing the various tents during the 2014–2015 summer expedition. GPR: ground-penetrating radar; AMOS: automatic meteorological observation system. (d) Investigation lines for ground penetrating radar (GPR). Details of the measurements and results will be presented in Figure 3")
![Ice surface velocity and flow direction (red arrows) around the drilling site, derived from satellite radar interferometry data [39]. The background is Sentinel-1 synthetic aperture radar image acquired on June 17, 2017](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_97_image_1.png "Ice surface velocity and flow direction (red arrows) around the drilling site, derived from satellite radar interferometry data [39]. The background is Sentinel-1 synthetic aperture radar image acquired on June 17, 2017")
![Ground-penetrating radar (GPR) data plotted using the program Surfer. The GPR data were acquired using a MALÅ Rough Terrain Antenna (RTA) system. The control unit linked to global positioning system (GPS) receiver measured signals with 25 MHz center frequency, 4.4 m transmitter-receiver separation, 1 trace s−1 record, 13,000 ns time window, and 8 stacks. The raw data were post-processed by background removal, gain, and Kirchhoff migrationusing the program Reflexw. The radio wave velocity was employed as 0.20 m ns−1 for snow (0–20 m depth), 0.19 m ns−1 for firn (20–50 m depth), and 0.17 m ns−1 for ice (>50 m depth) [46]](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_98_image_1.png "Ground-penetrating radar (GPR) data plotted using the program Surfer. The GPR data were acquired using a MALÅ Rough Terrain Antenna (RTA) system. The control unit linked to global positioning system (GPS) receiver measured signals with 25 MHz center frequency, 4.4 m transmitter-receiver separation, 1 trace s−1 record, 13,000 ns time window, and 8 stacks. The raw data were post-processed by background removal, gain, and Kirchhoff migrationusing the program Reflexw. The radio wave velocity was employed as 0.20 m ns−1 for snow (0–20 m depth), 0.19 m ns−1 for firn (20–50 m depth), and 0.17 m ns−1 for ice (>50 m depth) [46]")
![Plots of (a) ice age, (b) density, and (c) longitudinal strain rate as a factor of increasing depth. (a) The ice age of the core was derived from Yang et al. [44]. (b) Density is computed from the measured weight of the core divided by volume. (c) Longitudinal strain rate is calculated from density divided by time. Upper and lower bound horizontal strain rates are presented as a grey line](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_99_image_1.png "Plots of (a) ice age, (b) density, and (c) longitudinal strain rate as a factor of increasing depth. (a) The ice age of the core was derived from Yang et al. [44]. (b) Density is computed from the measured weight of the core divided by volume. (c) Longitudinal strain rate is calculated from density divided by time. Upper and lower bound horizontal strain rates are presented as a grey line")
![Plots of (a) J-index, (b) mean grain size, and (c) shape factor, K, as a factor of increasing depth. The range presented as black arrows and a blue arrow and in (b) denote thestandard deviation and peak grain size, respectively. The shape factor is calculated from eigenvalues [53]](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_103_image_1.png "Plots of (a) J-index, (b) mean grain size, and (c) shape factor, K, as a factor of increasing depth. The range presented as black arrows and a blue arrow and in (b) denote thestandard deviation and peak grain size, respectively. The shape factor is calculated from eigenvalues [53]")
![Expression and identification of the subcellular localization of FfIBP in bacteria. (A) Western immunoblot analysis of FfIBP from bacterial cell fractions detected by His-tag antibodies. Cell fractions are shown above the lanes: W., whole cell; C., cytoplasm; P., periplasm; M., membrane fractions. The whole cells with empty vector (W. emp.) were considered as a negative control. Different amounts of recombinant FfIBP (amino acids 27 –276) with His-tag were used as a positive control [11]. (B) Confocal microscopy images of cells harboring empty, FfIBP, mFfIBP, and C107S vectors. Protein-expressing bacteria were incubated with Ni-NTA-ATTO 550, washed, and examined under fluorescence microscope LSM800. Scale bars represent 10 μm. The image from the mFfIBP sample with low laser intensity was shown in the right panel to identify the specific localization of IBPs](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_134_image_1.png "Expression and identification of the subcellular localization of FfIBP in bacteria. (A) Western immunoblot analysis of FfIBP from bacterial cell fractions detected by His-tag antibodies. Cell fractions are shown above the lanes: W., whole cell; C., cytoplasm; P., periplasm; M., membrane fractions. The whole cells with empty vector (W. emp.) were considered as a negative control. Different amounts of recombinant FfIBP (amino acids 27 –276) with His-tag were used as a positive control [11]. (B) Confocal microscopy images of cells harboring empty, FfIBP, mFfIBP, and C107S vectors. Protein-expressing bacteria were incubated with Ni-NTA-ATTO 550, washed, and examined under fluorescence microscope LSM800. Scale bars represent 10 μm. The image from the mFfIBP sample with low laser intensity was shown in the right panel to identify the specific localization of IBPs")
![Peak ratio of Raman spectroscopy (3,140/3,430 cm-1). The 10 ice granules, brine pockets, and QLL region areas were scanned five times and averaged. The averaged data indicated on the right correspond to the data in the graph. a single asterisk [*] indicates p < 0.05, and double asterisks [**] indicate p < 0.01) by unpaired t-test). ns: not significant](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_137_image_218.png "Peak ratio of Raman spectroscopy (3,140/3,430 cm-1). The 10 ice granules, brine pockets, and QLL region areas were scanned five times and averaged. The averaged data indicated on the right correspond to the data in the graph. a single asterisk [*] indicates p < 0.05, and double asterisks [**] indicate p < 0.01) by unpaired t-test). ns: not significant")
![Changing actinic fluxes and iodine concentrations at Dome C. Iodine concentration (grey line – raw data; bold black line 10 year smoothing) and [I] anomalies, express as ngg-1 (blue, positive, and red, negative solid lines with respect to the mean iodine concentration for the period 1833 - 2011) have been compared with the Springtime mean total ozone column (red dots – TOCSP in Dobson Unit) calculated for the Southern Polar Cap (poleward of 63ºS). The top panel shows the modelled springtime Actinic Flux at 300 nm (purple square - AF300, units in quanta cm−2 s−1 nm−1) at the Antarctic surface within the closest model gridpoint to Dome C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_152_image_1.png "Changing actinic fluxes and iodine concentrations at Dome C. Iodine concentration (grey line – raw data; bold black line 10 year smoothing) and [I] anomalies, express as ngg-1 (blue, positive, and red, negative solid lines with respect to the mean iodine concentration for the period 1833 - 2011) have been compared with the Springtime mean total ozone column (red dots – TOCSP in Dobson Unit) calculated for the Southern Polar Cap (poleward of 63ºS). The top panel shows the modelled springtime Actinic Flux at 300 nm (purple square - AF300, units in quanta cm−2 s−1 nm−1) at the Antarctic surface within the closest model gridpoint to Dome C")
![Iodide oxidation with H2O2 in aqueous phase and ice in the presence of LeIBP. (a) Time profile of I3 − production in aqueous phase (at 25 °C) or in ice (at -20 °C). (b) Production of I3 − in aqueous phase or ice after the 24 h reaction. Initial conditions: [I−] = 1 mM, [H2O2] = 0.5 mM, LeIBP = 100 ppm, pH = 4.0](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_169_image_1.png "Iodide oxidation with H2O2 in aqueous phase and ice in the presence of LeIBP. (a) Time profile of I3 − production in aqueous phase (at 25 °C) or in ice (at -20 °C). (b) Production of I3 − in aqueous phase or ice after the 24 h reaction. Initial conditions: [I−] = 1 mM, [H2O2] = 0.5 mM, LeIBP = 100 ppm, pH = 4.0")
![I3 − production in aqueous phase (at 25 °C) or ice (at -20 °C) after the 24 h reaction under various conditions, against (a) [I−], (b) [H2O2], and (c) LeIBP concentration](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_170_image_219.png "I3 − production in aqueous phase (at 25 °C) or ice (at -20 °C) after the 24 h reaction under various conditions, against (a) [I−], (b) [H2O2], and (c) LeIBP concentration")
![Change in UV–Vis absorption spectra of CR before and after freezing of (a) H2O2 solution, (b) H2O2 with LeIBP solution. Initial condition conditions: freezing temperature = -20 °C, freezing time = 1 h, [H2O2] = 0.5 mM, LeIBP = 100 ppm, [CR] = 10 μM, initial pH 4.0](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_171_image_1.png "Change in UV–Vis absorption spectra of CR before and after freezing of (a) H2O2 solution, (b) H2O2 with LeIBP solution. Initial condition conditions: freezing temperature = -20 °C, freezing time = 1 h, [H2O2] = 0.5 mM, LeIBP = 100 ppm, [CR] = 10 μM, initial pH 4.0")
![I3 − production in aqueous phase (at 25 °C) or ice (at -20 °C) after 24 h reaction in (a) iodide solution, (b) iodide solution with LeIBP, (c) iodide solution with H2O2, and (d) iodide solution with LeIBP and H2O2, under different pH conditions. Initial condition: [I−] = 1 mM, [H2O2] = 0.5 mM, LeIBP = 100 ppm](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_172_image_220.png "I3 − production in aqueous phase (at 25 °C) or ice (at -20 °C) after 24 h reaction in (a) iodide solution, (b) iodide solution with LeIBP, (c) iodide solution with H2O2, and (d) iodide solution with LeIBP and H2O2, under different pH conditions. Initial condition: [I−] = 1 mM, [H2O2] = 0.5 mM, LeIBP = 100 ppm")
![Optical images of the ice granules of (a) H2O2 frozen solution, (b) H2O2 frozen solution with BSA, and (c) H2O2 frozen solution with LeIBP. Initial condition: [H2O2] = 0.5 mM, LeIBP = 100 ppm, BSA = 100 ppm, pH 4.0, cooling temperature: -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_173_image_1.png "Optical images of the ice granules of (a) H2O2 frozen solution, (b) H2O2 frozen solution with BSA, and (c) H2O2 frozen solution with LeIBP. Initial condition: [H2O2] = 0.5 mM, LeIBP = 100 ppm, BSA = 100 ppm, pH 4.0, cooling temperature: -20 °C")
![Optical image of the frozen (a, b) H2O2 solution, (c, d) H2O2 with LeIBP and their spatial distribution based on the Raman peak intensity at 880 cm−1, for O−O stretching vibration mode from H2O2. The signal intensity was ordered using a rainbow color scale. (black: low à red: high). Initial condition: [H2O2] = 1 mM, LeIBP 100 ppm, pH 4.0, cooling temperature: -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_174_image_1.png "Optical image of the frozen (a, b) H2O2 solution, (c, d) H2O2 with LeIBP and their spatial distribution based on the Raman peak intensity at 880 cm−1, for O−O stretching vibration mode from H2O2. The signal intensity was ordered using a rainbow color scale. (black: low à red: high). Initial condition: [H2O2] = 1 mM, LeIBP 100 ppm, pH 4.0, cooling temperature: -20 °C")
![Chemical composition changes of filtrate after a batch experiment with a pH 3 solution and DW. (a) [Na+], (b) [K+], (c) [Mg2+], and (d) [Ca2+]](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_188_image_221.png "Chemical composition changes of filtrate after a batch experiment with a pH 3 solution and DW. (a) [Na+], (b) [K+], (c) [Mg2+], and (d) [Ca2+]")
![Chemical composition changes of filtrate after batch experiment with pH 2 solution and DW. (a) [Na+], (b) [K+], (c) [Mg2+], and (d) [Ca2+]](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_189_image_222.png "Chemical composition changes of filtrate after batch experiment with pH 2 solution and DW. (a) [Na+], (b) [K+], (c) [Mg2+], and (d) [Ca2+]")
![Concentrations of iodine species ((A) Tot-I, (B) iodide, (C) RI, and (D) OICs) in the presence of HA, FA, AHA, and AHA-Na, and (E) OICs in iodide-added river water after 120 h in aqueous, frozen, and freeze–thaw cycled Fe(III)/I– systems. Experimental conditions: (A–D) [I–]0 = 10 μM, [Fe(III)]0 = 50 μM, [NOM]0 = 10 ppm ([HA] = 5 mg C L –1, [FA] = 4.3 mg C/L, [AHA] = 4.1 mg C/L, and [AHA-Na] = 3.2 mg C/L), pHi = 3.0, and (E) add 1 μM iodide and 50 μM Fe(III), and then adjust pH to 3.0.](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_215_image_1.png "Concentrations of iodine species ((A) Tot-I, (B) iodide, (C) RI, and (D) OICs) in the presence of HA, FA, AHA, and AHA-Na, and (E) OICs in iodide-added river water after 120 h in aqueous, frozen, and freeze–thaw cycled Fe(III)/I– systems. Experimental conditions: (A–D) [I–]0 = 10 μM, [Fe(III)]0 = 50 μM, [NOM]0 = 10 ppm ([HA] = 5 mg C L –1, [FA] = 4.3 mg C/L, [AHA] = 4.1 mg C/L, and [AHA-Na] = 3.2 mg C/L), pHi = 3.0, and (E) add 1 μM iodide and 50 μM Fe(III), and then adjust pH to 3.0.")
![Concentrations of (A) Tot-I, (B) iodide, (C) RI, and (D)OICs after 120 h in aqueous, frozen, and freeze−thaw cycledsolutions of HA/I− in the presence of different types of iron oxides.The BET surface area of iron oxide samples: α-Fe2O3 (8 m2/g); γFe2O3 (36 m2/g); α-FeOOH (12 m2/g); Fe3O4 (8 m2/g).Experimental conditions: [I−]0 = 10 μM, [Iron oxides] = 0.1 g/L,[HA]0 = 5 mg C/L, and pHi = 3.0](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_216_image_1.png "Concentrations of (A) Tot-I, (B) iodide, (C) RI, and (D)OICs after 120 h in aqueous, frozen, and freeze−thaw cycledsolutions of HA/I− in the presence of different types of iron oxides.The BET surface area of iron oxide samples: α-Fe2O3 (8 m2/g); γFe2O3 (36 m2/g); α-FeOOH (12 m2/g); Fe3O4 (8 m2/g).Experimental conditions: [I−]0 = 10 μM, [Iron oxides] = 0.1 g/L,[HA]0 = 5 mg C/L, and pHi = 3.0")
![van Krevelen diagrams of OICs generated in (A) aqueous and (B) freeze−thaw cycled Fe(III)/I−/HA solutions. Stacked bar diagramsillustrate the contribution of different (C) chemical compositions and (D) classes to total OICs and OICs-I. Experimental conditions: [I−]0 = 10μM, [Fe(III)] = 50 μM, [HA]0 = 5 mg C/L, pHi = 3.0, total reaction time is 120 h (aqueous reaction or five freeze−thaw cycles)](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_218_image_1.png "van Krevelen diagrams of OICs generated in (A) aqueous and (B) freeze−thaw cycled Fe(III)/I−/HA solutions. Stacked bar diagramsillustrate the contribution of different (C) chemical compositions and (D) classes to total OICs and OICs-I. Experimental conditions: [I−]0 = 10μM, [Fe(III)] = 50 μM, [HA]0 = 5 mg C/L, pHi = 3.0, total reaction time is 120 h (aqueous reaction or five freeze−thaw cycles)")
![Time profiles of [Cr(VI)] dissolved out from chromium oxide (Cr2O3) that was oxidized by (A) hypochlorite (HOCl), (B) hypobromite (HOBr), (C) bromate (BrO3 -), (D) periodate (IO4 -), and (E) other oxyhalide anions (ClO3 -, ClO4 -, IO3 -) under aqueous (20 °C) and frozen (-20 °C) solutions. Experimental conditions: pHi = 4, [Cr2O3]0 = 0.2 g/L, [Oxyhalide anion]0 = 0, 5, 10 μM (for A, B, C, D) or 10 mM (for C, E) in dark condition](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_236_image_1.png "Time profiles of [Cr(VI)] dissolved out from chromium oxide (Cr2O3) that was oxidized by (A) hypochlorite (HOCl), (B) hypobromite (HOBr), (C) bromate (BrO3 -), (D) periodate (IO4 -), and (E) other oxyhalide anions (ClO3 -, ClO4 -, IO3 -) under aqueous (20 °C) and frozen (-20 °C) solutions. Experimental conditions: pHi = 4, [Cr2O3]0 = 0.2 g/L, [Oxyhalide anion]0 = 0, 5, 10 μM (for A, B, C, D) or 10 mM (for C, E) in dark condition")
![Concentrations (μM) of other halogen species produced from the (A) Cr2O3 and (B) Cr(OH)3 oxidation in aqueous and ice phase with different oxyhalide anions as an oxidant. Experimental conditions: pHi = 4, [Cr2O3, Cr(OH)3]0 = 0.2 g/L, [Oxyhalide anion]0 = 10 μM, dark reaction for 24 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_237_image_227.png "Concentrations (μM) of other halogen species produced from the (A) Cr2O3 and (B) Cr(OH)3 oxidation in aqueous and ice phase with different oxyhalide anions as an oxidant. Experimental conditions: pHi = 4, [Cr2O3, Cr(OH)3]0 = 0.2 g/L, [Oxyhalide anion]0 = 10 μM, dark reaction for 24 h")
![pH-dependent Cr(VI) production from the oxidative dissolution of chromium oxide (Cr2O3) in frozen (-20 °C) and aqueous (20 °C) solutions in the presence of oxyhalide anions; (A) HOClO, (B) HOBrO, (C) BrO3 -, and (D) IO4 -. Experimental conditions: [Cr2O3]0 = 0.2 g/L, [Oxyhalide anion]0 = 10 μM , dark reaction for 24 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_238_image_1.png "pH-dependent Cr(VI) production from the oxidative dissolution of chromium oxide (Cr2O3) in frozen (-20 °C) and aqueous (20 °C) solutions in the presence of oxyhalide anions; (A) HOClO, (B) HOBrO, (C) BrO3 -, and (D) IO4 -. Experimental conditions: [Cr2O3]0 = 0.2 g/L, [Oxyhalide anion]0 = 10 μM , dark reaction for 24 h")
![Cr(VI) production from (A) Cr2O3(s), (B) Cr(OH)3(s) and (C) Cr3+(aq) oxidation by oxyhalide anions in aqueous (20 °C) and frozen (-20 °C) solution. Experimental conditions: pHi = 4, (A, B) [Cr2O3, Cr(OH)3]0 = 0.2 g/L, (C) [Cr(III)]0 = 1 mM, [Oxyhalide anion]0 = 10 μM, dark reaction for 24 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_240_image_229.png "Cr(VI) production from (A) Cr2O3(s), (B) Cr(OH)3(s) and (C) Cr3+(aq) oxidation by oxyhalide anions in aqueous (20 °C) and frozen (-20 °C) solution. Experimental conditions: pHi = 4, (A, B) [Cr2O3, Cr(OH)3]0 = 0.2 g/L, (C) [Cr(III)]0 = 1 mM, [Oxyhalide anion]0 = 10 μM, dark reaction for 24 h")
![Effects of dissolved gas (Ar, air, O2) on the oxidative dissolution of Cr(VI) from chrome oxide in (A) aqueous (20 °C) and (B) frozen (-20 °C) solution. A pre-purged solution was frozen. Experimental conditions: [Cr2O3]0 = 0.2 g/L, [Oxyhalide anion]0 = 10 μM, dark reaction for 24 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_241_image_230.png "Effects of dissolved gas (Ar, air, O2) on the oxidative dissolution of Cr(VI) from chrome oxide in (A) aqueous (20 °C) and (B) frozen (-20 °C) solution. A pre-purged solution was frozen. Experimental conditions: [Cr2O3]0 = 0.2 g/L, [Oxyhalide anion]0 = 10 μM, dark reaction for 24 h")
![Time profiles of [Cr(VI)] dissolved out from Cr2O3 that was oxidized by (A) bromate (BrO3 -), (B) periodate (IO4 -) in the presence of dissolved organic matter (DOM) in frozen (-20 °C) and aqueous (20 °C) solution. Experimental conditions: pHi = 4, [Cr2O3]0 = 0.2 g/L, [Oxyhalide anion]0 = 10 μM, [Fulvic acid]0 = 0, 1, 3 ppm in dark condition](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_242_image_1.png "Time profiles of [Cr(VI)] dissolved out from Cr2O3 that was oxidized by (A) bromate (BrO3 -), (B) periodate (IO4 -) in the presence of dissolved organic matter (DOM) in frozen (-20 °C) and aqueous (20 °C) solution. Experimental conditions: pHi = 4, [Cr2O3]0 = 0.2 g/L, [Oxyhalide anion]0 = 10 μM, [Fulvic acid]0 = 0, 1, 3 ppm in dark condition")
![(a) Optical image of the frozen solution containing Cr6+ and Fe2+. Local concentrations of Cr6+ in the frozen solution after additional time: (b) 0.5 h and (c) 1.0 h. Experimental conditions: [Cr6+] = 1 mM, [Fe2+] = 1 mM, and pH 3.0. For part a, the temperature decreased from 0 to –40 °C at a rate of –2.0 °C/min. For parts b and c, the temperature was maintained at –40 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_346_image_242.png "(a) Optical image of the frozen solution containing Cr6+ and Fe2+. Local concentrations of Cr6+ in the frozen solution after additional time: (b) 0.5 h and (c) 1.0 h. Experimental conditions: [Cr6+] = 1 mM, [Fe2+] = 1 mM, and pH 3.0. For part a, the temperature decreased from 0 to –40 °C at a rate of –2.0 °C/min. For parts b and c, the temperature was maintained at –40 °C")
![Change of UV-visible absorption spectra of CR after freezing. Experimental conditions: freezing temperature = –20 °C, freezing time = 1 h, [Cr6+] = 20 μM, [Fe2+] = 70μM, [CR] = 6.7 μM, and pH 4.0](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_347_image_1.png "Change of UV-visible absorption spectra of CR after freezing. Experimental conditions: freezing temperature = –20 °C, freezing time = 1 h, [Cr6+] = 20 μM, [Fe2+] = 70μM, [CR] = 6.7 μM, and pH 4.0")
![Effects of Fe2+ concentration increase and/or pH decrease on the Fe2+-mediated reduction of Cr6+ in water. Experimental conditions: reaction temperature = 25 °C, reaction time = 2 h, [Cr6+] = 20 μM, [Fe2+] = 70 or 700 μM, and pH = 2.0, 3.0, or 4.0](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_348_image_243.png "Effects of Fe2+ concentration increase and/or pH decrease on the Fe2+-mediated reduction of Cr6+ in water. Experimental conditions: reaction temperature = 25 °C, reaction time = 2 h, [Cr6+] = 20 μM, [Fe2+] = 70 or 700 μM, and pH = 2.0, 3.0, or 4.0")
![Effects of (a and b) Fe2+ concentration, (c and d) pH, and (e and f) temperature on the redox reaction between Cr6+ and Fe2+ in water and ice. Experimental conditions: [Cr6+] = 20 μM, [Fe2+] = 70 μM in the cases of c–f, pH 4.0 in the cases of a–b and e–f, reaction temperature = 25 °C or –20 °C in the cases of a–d, and reaction time = 0.5 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_349_image_244.png "Effects of (a and b) Fe2+ concentration, (c and d) pH, and (e and f) temperature on the redox reaction between Cr6+ and Fe2+ in water and ice. Experimental conditions: [Cr6+] = 20 μM, [Fe2+] = 70 μM in the cases of c–f, pH 4.0 in the cases of a–b and e–f, reaction temperature = 25 °C or –20 °C in the cases of a–d, and reaction time = 0.5 h")
![Time profiles of (a) Cr6+ and (b) Fe2+ concentrations in electroplating wastewater and Cr6+ solution during the freezing process. Experimental conditions: reaction temperature = –20 °C, [Cr6+] = 20 μM, [Fe2+] = 70 μM, and pH 4.0 (with pH adjustment) or 4.5 (without pH adjustment)](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_350_image_245.png "Time profiles of (a) Cr6+ and (b) Fe2+ concentrations in electroplating wastewater and Cr6+ solution during the freezing process. Experimental conditions: reaction temperature = –20 °C, [Cr6+] = 20 μM, [Fe2+] = 70 μM, and pH 4.0 (with pH adjustment) or 4.5 (without pH adjustment)")
![Time profile of (a) Cr (VI) concentration and (b) the production of SO4 2- with/without Cr (VI)in water and ice. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, pHi 4.0, and freezing temperature = -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_365_image_246.png "Time profile of (a) Cr (VI) concentration and (b) the production of SO4 2- with/without Cr (VI)in water and ice. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, pHi 4.0, and freezing temperature = -20 °C")
![UV-visible absorption spectra of CR in aqueous and ice phases containing Cr (VI), H2S, and CR. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, [CR]i = 6.67 μM, pHi 4.0, aqueous solution temperature = 25 °C, and freezing temperature = -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_366_image_1.png "UV-visible absorption spectra of CR in aqueous and ice phases containing Cr (VI), H2S, and CR. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, [CR]i = 6.67 μM, pHi 4.0, aqueous solution temperature = 25 °C, and freezing temperature = -20 °C")
![Optical images of Cr (VI) distribution in the ice grain boundary regions after (a) 0h, (b) 1 h and (c) 1.5 h, respectively. Experimental conditions were as follows: [Cr (VI)]i = 1 mM, [H2S]i = 1 mM, pHi 3.0, and freezing temperature = -40 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_367_image_1.png "Optical images of Cr (VI) distribution in the ice grain boundary regions after (a) 0h, (b) 1 h and (c) 1.5 h, respectively. Experimental conditions were as follows: [Cr (VI)]i = 1 mM, [H2S]i = 1 mM, pHi 3.0, and freezing temperature = -40 °C")
![Effect of H2S concentration on the reduction of Cr (VI) in water (a) and in ice (b). Experimental conditions were as follows: [Cr (VI)]i = 20 μM, pHi 4.0, freezing temperature = -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_368_image_1.png "Effect of H2S concentration on the reduction of Cr (VI) in water (a) and in ice (b). Experimental conditions were as follows: [Cr (VI)]i = 20 μM, pHi 4.0, freezing temperature = -20 °C")
![Effect of pHi on the redox conversion of Cr (VI) by H2S in water and ice. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S/HS-/S2-]i = 30 μM, freezing temperature = -20 °C, and reaction time = 2 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_369_image_1.png "Effect of pHi on the redox conversion of Cr (VI) by H2S in water and ice. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S/HS-/S2-]i = 30 μM, freezing temperature = -20 °C, and reaction time = 2 h")
![Effect of freezing temperature on the redox reaction of Cr (VI) by H2S compared with that in water. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, and pHi = 4.0](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_370_image_1.png "Effect of freezing temperature on the redox reaction of Cr (VI) by H2S compared with that in water. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, and pHi = 4.0")
![Effect of increase in H2S concentration and/or decrease in pHi on the reduction of Cr (VI) by H2Sin water. Experimental conditions were as follows: pHi decrease: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, and pHi 2.0. [H2S] increase: [Cr (VI)]i = 20 μM, [H2S]i = 3 mM, and pHi 4.0. [H2S] increase and pHi decrease: [Cr (VI)]i = 20 μM, [H2S]i = 3 mM, and pHi 2.0. References conditions: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, and pHi 4.0 in both water and ice. Reaction time = 2 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_371_image_1.png "Effect of increase in H2S concentration and/or decrease in pHi on the reduction of Cr (VI) by H2Sin water. Experimental conditions were as follows: pHi decrease: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, and pHi 2.0. [H2S] increase: [Cr (VI)]i = 20 μM, [H2S]i = 3 mM, and pHi 4.0. [H2S] increase and pHi decrease: [Cr (VI)]i = 20 μM, [H2S]i = 3 mM, and pHi 2.0. References conditions: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, and pHi 4.0 in both water and ice. Reaction time = 2 h")
![Cr (VI) reduction in Cr (VI)-contaminated in electroplating wastewater and artificial Cr (VI) solution in ice. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, pHi 4.0, and freezing temperature = -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_372_image_1.png "Cr (VI) reduction in Cr (VI)-contaminated in electroplating wastewater and artificial Cr (VI) solution in ice. Experimental conditions were as follows: [Cr (VI)]i = 20 μM, [H2S]i = 30 μM, pHi 4.0, and freezing temperature = -20 °C")
![Residual ratios of total Cr and Cr6+ in water (25 °C) and ice (-20 °C) in the system. Experimental conditions: [tea waste] = 0.1 g/L, pHi = 3.5, reaction time = 5 h, and freezing temperature = -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_412_image_247.png "Residual ratios of total Cr and Cr6+ in water (25 °C) and ice (-20 °C) in the system. Experimental conditions: [tea waste] = 0.1 g/L, pHi = 3.5, reaction time = 5 h, and freezing temperature = -20 °C")
![Reduction of Cr6+ in the presence of tea waste in (a) water (25 °C) and (b) ice (-20 °C), where C is the residual concentration of Cr6+ in the system. Experimental conditions: C0 = [Cr6+]i = 20 μM, [tea waste] = 0.1 g/L, pHi = 3.5, and freezing temperature = -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_413_image_248.png "Reduction of Cr6+ in the presence of tea waste in (a) water (25 °C) and (b) ice (-20 °C), where C is the residual concentration of Cr6+ in the system. Experimental conditions: C0 = [Cr6+]i = 20 μM, [tea waste] = 0.1 g/L, pHi = 3.5, and freezing temperature = -20 °C")
![Changes of UV-vis absorption spectra of cresol red before and after freezing under the experimental conditions [Cr6+]i = 20 μM, pHi = 3.5, freezing temperature = -20 °C, and freezing time = 1 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_414_image_1.png "Changes of UV-vis absorption spectra of cresol red before and after freezing under the experimental conditions [Cr6+]i = 20 μM, pHi = 3.5, freezing temperature = -20 °C, and freezing time = 1 h")
![Excitation-emission matrix (EEM) of the tea extracts before and after reaction. Experimental conditions: C0 = [Cr6+]i = 20 μM, [tea waste] = 0.1 g/L, pHi = 3.5, and freezing temperature = -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_415_image_1.png "Excitation-emission matrix (EEM) of the tea extracts before and after reaction. Experimental conditions: C0 = [Cr6+]i = 20 μM, [tea waste] = 0.1 g/L, pHi = 3.5, and freezing temperature = -20 °C")
![Effect of pH on the reduction of Cr6+ by tea wastes in (a) water and (b) ice. Experimental conditions: C0 = [Cr6+]i = 20 μM, [tea waste] = 0.1 g/L, freezing temperature = -20 °C, and reaction time = 5h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_417_image_250.png "Effect of pH on the reduction of Cr6+ by tea wastes in (a) water and (b) ice. Experimental conditions: C0 = [Cr6+]i = 20 μM, [tea waste] = 0.1 g/L, freezing temperature = -20 °C, and reaction time = 5h")
![Effect of dosage of tea waste on (a) the reduction of Cr6+ by tea wastes, and (b) the adsorptive removal of Cr by tea wastes in water and ice, where C0 and C are the initial and residual concentration of Cr6+ in the system and Cremoval is the adsorptive removal concentration of Cr6+ by the tea wastes. Experimental conditions: C0 = [Cr6+]i = 20 μM, pHi = 3.5, freezing temperature = -20 °C, and reaction time = 5h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_418_image_251.png "Effect of dosage of tea waste on (a) the reduction of Cr6+ by tea wastes, and (b) the adsorptive removal of Cr by tea wastes in water and ice, where C0 and C are the initial and residual concentration of Cr6+ in the system and Cremoval is the adsorptive removal concentration of Cr6+ by the tea wastes. Experimental conditions: C0 = [Cr6+]i = 20 μM, pHi = 3.5, freezing temperature = -20 °C, and reaction time = 5h")
![(a and b) Optical image of the frozen Cr6+ with chamomile solution and its Raman spectra in LLLs (site marked with red circle in Fig. 7a) and ice crystal (site marked with black circle in Fig. 7b), (c and d) optical image of the frozen Cr6+ with chamomile solution and its spatial distribution based on the peak intensity at 900 cm-1, (e-f) confocal microscopy image of the frozen Cr6+ with chamomile, and merged image obtained using the DIC image and fluorescence image of chamomile extracts under the conditions of C0 = [Cr6+]i = 1 mM, [chamomile]i = 5.0 g/L, and pHi = 3.5](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_419_image_252.png "(a and b) Optical image of the frozen Cr6+ with chamomile solution and its Raman spectra in LLLs (site marked with red circle in Fig. 7a) and ice crystal (site marked with black circle in Fig. 7b), (c and d) optical image of the frozen Cr6+ with chamomile solution and its spatial distribution based on the peak intensity at 900 cm-1, (e-f) confocal microscopy image of the frozen Cr6+ with chamomile, and merged image obtained using the DIC image and fluorescence image of chamomile extracts under the conditions of C0 = [Cr6+]i = 1 mM, [chamomile]i = 5.0 g/L, and pHi = 3.5")
![Reduction of Cr6+ in electroplating wastewater. Experimental conditions: C0 = [Cr6+]i = 20 μM, [tea waste] = 0.1 g/L, pHi = 3.5, reaction time = 5 h, and freezing temperature = -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_420_image_253.png "Reduction of Cr6+ in electroplating wastewater. Experimental conditions: C0 = [Cr6+]i = 20 μM, [tea waste] = 0.1 g/L, pHi = 3.5, reaction time = 5 h, and freezing temperature = -20 °C")
![Time profiles of Cr(VI) concentration during treatment with raw and washed SCG under the experimental conditions: [Cr(VI)]i = 20 μM, [SCG or washed SCG] = 0.1 g/L, pHi = 3.0, and freezing temperature = -20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_436_image_254.png "Time profiles of Cr(VI) concentration during treatment with raw and washed SCG under the experimental conditions: [Cr(VI)]i = 20 μM, [SCG or washed SCG] = 0.1 g/L, pHi = 3.0, and freezing temperature = -20 °C")
![Effect of pH on the H2O2/NO2 − system. (a) the concentration of BA. (b) the concentration of H2O2, NO2 −, and NO3 −. Experimental conditions: [BA]0 = 20 μM; [H2O2]0 = 1 mM; [NO2 −]0 = 0.5 mM; Temperature: the frozen system (Fz.) = −20℃; the aqueous system (Aq.) = 25℃; Reaction time = 1 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_463_image_255.png "Effect of pH on the H2O2/NO2 − system. (a) the concentration of BA. (b) the concentration of H2O2, NO2 −, and NO3 −. Experimental conditions: [BA]0 = 20 μM; [H2O2]0 = 1 mM; [NO2 −]0 = 0.5 mM; Temperature: the frozen system (Fz.) = −20℃; the aqueous system (Aq.) = 25℃; Reaction time = 1 h")
![(a) The UV-visible absorption spectra of CR. Insert = the color of cresol red. Experimental conditions: [CR]0 = 10 μM; [H2O2]0 = 1 mM; [NO2 −]0 = 0.5 mM; pHi = 4.0 (adjusted by HClO4); Temperature: the frozen system (Fz.) = −20 ℃; the aqueous system (Aq.) = 25 ℃. (b) The microscope image of ice grain boundary and the distributions of reagents which are represented by the Raman peak intensity. Note that the peaks were normalized because of the relatively high intensity of NO3 − (1050 cm−1) than the others. Experimental conditions: [H2O2]0 = 40 mM; [NO2 −]0 = 20 mM; [BA]0 = 1 mM; [HCl]0 = 5 mM](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_464_image_1.png "(a) The UV-visible absorption spectra of CR. Insert = the color of cresol red. Experimental conditions: [CR]0 = 10 μM; [H2O2]0 = 1 mM; [NO2 −]0 = 0.5 mM; pHi = 4.0 (adjusted by HClO4); Temperature: the frozen system (Fz.) = −20 ℃; the aqueous system (Aq.) = 25 ℃. (b) The microscope image of ice grain boundary and the distributions of reagents which are represented by the Raman peak intensity. Note that the peaks were normalized because of the relatively high intensity of NO3 − (1050 cm−1) than the others. Experimental conditions: [H2O2]0 = 40 mM; [NO2 −]0 = 20 mM; [BA]0 = 1 mM; [HCl]0 = 5 mM")
![The influence of the initial H2O2:NO2 − ratio on the BA decomposition in (a) the aqueous, and (b) the frozen H2O2:NO2 −− system. Experimental conditions: [BA]0 = 20 μM; pHi = 4.0 (adjusted by HClO4); Reaction time = 1 h; Temperature: the frozen system (Fz.) = −20 ℃; the aqueous system (Aq.) = 25 ℃. (c) The acidic aqueous system of pH 3. Experimental conditions: [BA]0 = 20 μM; [H2O2]0 = 1 mM; pHi = 3.0 (adjusted by HClO4); Reaction time = 1 h. (d) The influence of the initial BA concentration on the BA decomposition in the frozen H2O2:NO2 −− system. Experimental conditions: [H2O2]0 = 1 mM; [NO2 −]0 = 0.5 mM; pHi = 4.0 (adjusted by HClO4); Reaction time = 1 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_465_image_256.png "The influence of the initial H2O2:NO2 − ratio on the BA decomposition in (a) the aqueous, and (b) the frozen H2O2:NO2 −− system. Experimental conditions: [BA]0 = 20 μM; pHi = 4.0 (adjusted by HClO4); Reaction time = 1 h; Temperature: the frozen system (Fz.) = −20 ℃; the aqueous system (Aq.) = 25 ℃. (c) The acidic aqueous system of pH 3. Experimental conditions: [BA]0 = 20 μM; [H2O2]0 = 1 mM; pHi = 3.0 (adjusted by HClO4); Reaction time = 1 h. (d) The influence of the initial BA concentration on the BA decomposition in the frozen H2O2:NO2 −− system. Experimental conditions: [H2O2]0 = 1 mM; [NO2 −]0 = 0.5 mM; pHi = 4.0 (adjusted by HClO4); Reaction time = 1 h")
![Oxidative degradation of various benzene derivatives in the frozen H2O2:NO2 − system. Experimental conditions: [Organics]0 = 20 μM; [H2O]0 = 1 mM; [NO2 −]0 = 0.5 mM; pHi = 4.0; Reaction time = 1 h. The Hammett constants were obtained from the ref. 56-58](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_466_image_257.png "Oxidative degradation of various benzene derivatives in the frozen H2O2:NO2 − system. Experimental conditions: [Organics]0 = 20 μM; [H2O]0 = 1 mM; [NO2 −]0 = 0.5 mM; pHi = 4.0; Reaction time = 1 h. The Hammett constants were obtained from the ref. 56-58")
![The detected degradation by-products from LC-MS. Experimental conditions: [Organics]0 = 20 μM; [H2O2]0 = 1 mM; [NO2 −]0 = 0.5 mM; pHi = 4.0 (adjusted by HClO4); Temperature: the frozen system = −20 ℃; the aqueous system = 25 ℃; Reaction time = 1 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_467_image_1.png "The detected degradation by-products from LC-MS. Experimental conditions: [Organics]0 = 20 μM; [H2O2]0 = 1 mM; [NO2 −]0 = 0.5 mM; pHi = 4.0 (adjusted by HClO4); Temperature: the frozen system = −20 ℃; the aqueous system = 25 ℃; Reaction time = 1 h")
![The BA degradation by the H2O2/NO2 − system at natural imitated environments. Experimental conditions: [BA]0 = 20 μM; [NO2 −]0 = 0.5 mM; [H2O2]0 = 1 mM; Temperature: the frozen system (Fz.) = −20℃; the aqueous system (Aq.) = 25℃; Reaction time = 2 h; pH = 4 (adjusted by HClO4)](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_468_image_258.png "The BA degradation by the H2O2/NO2 − system at natural imitated environments. Experimental conditions: [BA]0 = 20 μM; [NO2 −]0 = 0.5 mM; [H2O2]0 = 1 mM; Temperature: the frozen system (Fz.) = −20℃; the aqueous system (Aq.) = 25℃; Reaction time = 2 h; pH = 4 (adjusted by HClO4)")
![EPR spectra obtained in the Fe2+/PMS system and the PMS/freezing system. Experimental conditions: [PMS] = 100 μM, [FFA] = 20 μM, [Fe2+] = 20 μM for the Fe2+/PMS system, [BMPO] = 1 mM, pH 3.0, reaction time = 0.5 h, and reaction temperatures = 25 °C for the Fe2+/PMS system and −20 °C for the PMS/freezing system](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_489_image_259.png "EPR spectra obtained in the Fe2+/PMS system and the PMS/freezing system. Experimental conditions: [PMS] = 100 μM, [FFA] = 20 μM, [Fe2+] = 20 μM for the Fe2+/PMS system, [BMPO] = 1 mM, pH 3.0, reaction time = 0.5 h, and reaction temperatures = 25 °C for the Fe2+/PMS system and −20 °C for the PMS/freezing system")
![Production of 7-hydroxycoumarin in the presence of coumarin in the PMS/freezing system and the Co2+/PMS system. Experimental conditions: [PMS] = 100 μM, [FFA] = 20 μM, [Co2+] = 20 μM for the Co2+/PMS system, [coumarin] = 1 mM, pH 3.0 or 10.0, and reaction temperatures = 25 °C for the Co2+/PMS system and −20 °C for the PMS/freezing system](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_490_image_1.png "Production of 7-hydroxycoumarin in the presence of coumarin in the PMS/freezing system and the Co2+/PMS system. Experimental conditions: [PMS] = 100 μM, [FFA] = 20 μM, [Co2+] = 20 μM for the Co2+/PMS system, [coumarin] = 1 mM, pH 3.0 or 10.0, and reaction temperatures = 25 °C for the Co2+/PMS system and −20 °C for the PMS/freezing system")
![(a) Optical image of the frozen PMS solution. (b) Raman spectra of PMS in the ice grain boundary (site marked with red circle in a) and ice crystal (site marked with blue circle in a). Spatial distributions of (c) PMS and (d) FFA in the frozen PMS and FFA solutions, respectively. Experimental conditions: [PMS] = 100 μM (for parts a, b, and c), [FFA] = 10 mM (for part d), pH 3.0, and freezing temperature = decrease from 0 to −20 °C at a rate of −1.5 °C/min](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_491_image_260.png "(a) Optical image of the frozen PMS solution. (b) Raman spectra of PMS in the ice grain boundary (site marked with red circle in a) and ice crystal (site marked with blue circle in a). Spatial distributions of (c) PMS and (d) FFA in the frozen PMS and FFA solutions, respectively. Experimental conditions: [PMS] = 100 μM (for parts a, b, and c), [FFA] = 10 mM (for part d), pH 3.0, and freezing temperature = decrease from 0 to −20 °C at a rate of −1.5 °C/min")
![(a) Degradation of 4-CP in the presence of Oxone and Cl− during the freezing and control experiments. (b) Concentration of 4-CP remaining after 4 h of reaction ([4-CP]f) with and without freezing as a function of [Cl−]. The inset shows [4-CP]f at micromolar concentrations of Cl−. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM for part a, [4-CP] = 100 μM, pHi 4.0, reaction temperature = 25 or −20 °C, and reaction time = 4 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_517_image_261.png "(a) Degradation of 4-CP in the presence of Oxone and Cl− during the freezing and control experiments. (b) Concentration of 4-CP remaining after 4 h of reaction ([4-CP]f) with and without freezing as a function of [Cl−]. The inset shows [4-CP]f at micromolar concentrations of Cl−. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM for part a, [4-CP] = 100 μM, pHi 4.0, reaction temperature = 25 or −20 °C, and reaction time = 4 h")
![Production of HOCl in the freezing/Oxone/Cl− system and control experiments. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, pHi 4.0, and reaction temperature = 25 or −20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_518_image_262.png "Production of HOCl in the freezing/Oxone/Cl− system and control experiments. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, pHi 4.0, and reaction temperature = 25 or −20 °C")
![Spatial distributions of (a and b) 4-CP and (c and d) Oxone in the frozen solutions in the (a and c) absence and (b and d) presence of Cl−. Experimental conditions: [Oxone] = 1 mM, [Cl−] = 5 mM, [4-CP] = 1 mM, pHi 4.0, freezing temperature = −20 °C, and freezing time = 1 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_519_image_1.png "Spatial distributions of (a and b) 4-CP and (c and d) Oxone in the frozen solutions in the (a and c) absence and (b and d) presence of Cl−. Experimental conditions: [Oxone] = 1 mM, [Cl−] = 5 mM, [4-CP] = 1 mM, pHi 4.0, freezing temperature = −20 °C, and freezing time = 1 h")
![UV−visible absorption spectra of CR in the presence of Oxone, Cl−, and 4-CP before and after freezing. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, [4-CP] = 100 μM, [CR] = 100 μM, pHi 4.0, freezing temperature = −20 °C, and freezing time = 1 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_520_image_263.png "UV−visible absorption spectra of CR in the presence of Oxone, Cl−, and 4-CP before and after freezing. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, [4-CP] = 100 μM, [CR] = 100 μM, pHi 4.0, freezing temperature = −20 °C, and freezing time = 1 h")
![Concentration of 4-CP remaining after 4 h of reaction ([4-CP]f) in the presence of Oxone and Cl− with and without freezing as a function of (a) [Oxone], (b) pHi, and (c) counter cation type. (d) Time profiles of the 4-CP concentration in the presence of Oxone and Cl− with variation in the freezing temperature. Experimental conditions: [Oxone] = 100 μM for parts b−d, [Cl−] = 500 μM, [4-CP] = 100 μM, pHi 4.0 for parts a, c, and d, reaction temperature = 25 or −20 °C for parts a−c, and reaction time = 4 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_521_image_1.png "Concentration of 4-CP remaining after 4 h of reaction ([4-CP]f) in the presence of Oxone and Cl− with and without freezing as a function of (a) [Oxone], (b) pHi, and (c) counter cation type. (d) Time profiles of the 4-CP concentration in the presence of Oxone and Cl− with variation in the freezing temperature. Experimental conditions: [Oxone] = 100 μM for parts b−d, [Cl−] = 500 μM, [4-CP] = 100 μM, pHi 4.0 for parts a, c, and d, reaction temperature = 25 or −20 °C for parts a−c, and reaction time = 4 h")
![Effect of the freezing method on the degradation kinetics of 4-CP in the freezing/Oxone/Cl− system. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, [4-CP] = 100 μM, pHi 4.0, and freezing temperature = −20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_522_image_1.png "Effect of the freezing method on the degradation kinetics of 4-CP in the freezing/Oxone/Cl− system. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, [4-CP] = 100 μM, pHi 4.0, and freezing temperature = −20 °C")
![(a) Degradation kinetics of phenol and substituted phenols in the freezing/Oxone/Cl− system. (b) Relationship between the first-order degradation rate constants (k) and the Hammett constants (σ+). Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, [phenol] or [substituted phenol] = 100 μM, pHi 4.0, and freezing temperature = −20 °C. P: phenol, 2-CP: 2-chlorophenol, 4-CP: 4-chlorophenol, 2-NP: 2-nitrophenol, 4-NP: 4-nitrophenol, 4-BP: 4-bromophenol, 4-MP: 4-methylphenol, and 2,4-DMP: 2,4-dimethylphenol](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_523_image_264.png "(a) Degradation kinetics of phenol and substituted phenols in the freezing/Oxone/Cl− system. (b) Relationship between the first-order degradation rate constants (k) and the Hammett constants (σ+). Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, [phenol] or [substituted phenol] = 100 μM, pHi 4.0, and freezing temperature = −20 °C. P: phenol, 2-CP: 2-chlorophenol, 4-CP: 4-chlorophenol, 2-NP: 2-nitrophenol, 4-NP: 4-nitrophenol, 4-BP: 4-bromophenol, 4-MP: 4-methylphenol, and 2,4-DMP: 2,4-dimethylphenol")
![Outdoor freezing experiments: the degradation of 4-CP in the freezing/Oxone/Cl− system with variation in the solution volume. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, [4-CP] = 100 μM, pHi 4.0, and temperature = from −15.0 to −19.5 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_524_image_265.png "Outdoor freezing experiments: the degradation of 4-CP in the freezing/Oxone/Cl− system with variation in the solution volume. Experimental conditions: [Oxone] = 100 μM, [Cl−] = 500 μM, [4-CP] = 100 μM, pHi 4.0, and temperature = from −15.0 to −19.5 °C")
![4-CP concentration profile versus elapsed time in the bicarbonate-PMS system with (a) various PMS concentrations and (b) various bicarbonate concentrations. [4-CP]0 = 0.02 mM; [HCO3 −]0 = 5 mM (at (a)); [PMS]0 = 0.5 mM (at (b)); pHi = 9; Temperature = 25 ℃ (aqueous condition) and -20 ℃ (frozen condition](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_543_image_1.png "4-CP concentration profile versus elapsed time in the bicarbonate-PMS system with (a) various PMS concentrations and (b) various bicarbonate concentrations. [4-CP]0 = 0.02 mM; [HCO3 −]0 = 5 mM (at (a)); [PMS]0 = 0.5 mM (at (b)); pHi = 9; Temperature = 25 ℃ (aqueous condition) and -20 ℃ (frozen condition")
![(a) Microscope image of ice grain boundary and representative Raman spectrum of the frozen bicarbonate-PMS solution. The signal at 984 cm-1 was selected to show the map image. Cooling speed = -2℃/min; terminal temperature = -20℃; [PMS]0 = 5 mM; [HCO3 −]0 = 10 mM. (b) 4-CP concentration profile at different freezing temperatures. Temperatures of -10, -20, and -30℃ were obtained via use of an ethanol bath and that of -196℃ was obtained using liquid N2. [4-CP]0 = 0.02 mM; [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM; pHi = 9](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_544_image_1.png "(a) Microscope image of ice grain boundary and representative Raman spectrum of the frozen bicarbonate-PMS solution. The signal at 984 cm-1 was selected to show the map image. Cooling speed = -2℃/min; terminal temperature = -20℃; [PMS]0 = 5 mM; [HCO3 −]0 = 10 mM. (b) 4-CP concentration profile at different freezing temperatures. Temperatures of -10, -20, and -30℃ were obtained via use of an ethanol bath and that of -196℃ was obtained using liquid N2. [4-CP]0 = 0.02 mM; [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM; pHi = 9")
![4-CP degradation by PMS. The solution pH was adjusted by (a) carbonate, (b) phosphate, and (c) hydroxide anion. [4-CP]0 = 0.02 mM; [PMS]0 = 0.5 mM; [anion]0 = 5 mM; temperature = 25 ℃ (aqueous) and -20 ℃ (frozen). (d) The color of cresol-red in the bicarbonate solution. [HCO3 −]0 = 5 mM; pHi = 9; Freezing temperature = -20 ℃](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_545_image_266.png "4-CP degradation by PMS. The solution pH was adjusted by (a) carbonate, (b) phosphate, and (c) hydroxide anion. [4-CP]0 = 0.02 mM; [PMS]0 = 0.5 mM; [anion]0 = 5 mM; temperature = 25 ℃ (aqueous) and -20 ℃ (frozen). (d) The color of cresol-red in the bicarbonate solution. [HCO3 −]0 = 5 mM; pHi = 9; Freezing temperature = -20 ℃")
![(a) EPR signal of TEMPO of the frozen PMS solution. NaOH was infused into the PMS solution to make the pH the same as that of the bicarbonate-PMS. [TEMP]0 = 1 mM; [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM (bicarbonate-PMS); [NaOH]0 = 0.325 mM (NaOH-PMS); pHi = 9; Temperature = -20℃. (b) Degradation of organic pollutants in the photo-excited RB and frozen bicarbonate-PMS. In RB systems: [RB]0 = 0.5 μM; [HCO3 −]0 = 1 mM, In PMS system: [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM; [organic substrate]0 = 0.05 mM; pHi = 9. (c) Degradation of 4-CP in the bicarbonate activated hydrogen peroxide system. [H2O2]0 = 200 mM; [HCO3 −]0 = 100 mM; [4-CP]0 = 0.2 mM; pHi = 9. (d) Degradation of organic pollutants in the bicarbonate-PDS system. [PDS]0 = 5 mM; [HCO3 −]0 = 5 mM; [organic substrate]0 = 0.05 mM; pHi = 9; temperature = 25 ℃ (aqueous) and -20 ℃ (frozen)](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_546_image_1.png "(a) EPR signal of TEMPO of the frozen PMS solution. NaOH was infused into the PMS solution to make the pH the same as that of the bicarbonate-PMS. [TEMP]0 = 1 mM; [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM (bicarbonate-PMS); [NaOH]0 = 0.325 mM (NaOH-PMS); pHi = 9; Temperature = -20℃. (b) Degradation of organic pollutants in the photo-excited RB and frozen bicarbonate-PMS. In RB systems: [RB]0 = 0.5 μM; [HCO3 −]0 = 1 mM, In PMS system: [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM; [organic substrate]0 = 0.05 mM; pHi = 9. (c) Degradation of 4-CP in the bicarbonate activated hydrogen peroxide system. [H2O2]0 = 200 mM; [HCO3 −]0 = 100 mM; [4-CP]0 = 0.2 mM; pHi = 9. (d) Degradation of organic pollutants in the bicarbonate-PDS system. [PDS]0 = 5 mM; [HCO3 −]0 = 5 mM; [organic substrate]0 = 0.05 mM; pHi = 9; temperature = 25 ℃ (aqueous) and -20 ℃ (frozen)")
![Degradation of various selected organic compounds in the frozen bicarbonate-PMS system. [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM; [organic substrate]0 = 0.02 mM; pHi = 9; temperature = -20 ℃](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_547_image_1.png "Degradation of various selected organic compounds in the frozen bicarbonate-PMS system. [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM; [organic substrate]0 = 0.02 mM; pHi = 9; temperature = -20 ℃")
![PMS concentrations obtained using various target organic substrates in the bicarbonate-PMS system with freezing. [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM; [organic substrate]0 = 0.02 mM; pHi = 9; temperature = -20 ℃](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_548_image_1.png "PMS concentrations obtained using various target organic substrates in the bicarbonate-PMS system with freezing. [PMS]0 = 0.5 mM; [HCO3 −]0 = 5 mM; [organic substrate]0 = 0.02 mM; pHi = 9; temperature = -20 ℃")
![(a) Time profiles of Cr(VI) concentration, (b) absorbance changes, and (c) time profiles of I−, I2, and I3 − concentrations in aqueous and frozen solutions containing Cr(VI) and I−. Experimental conditions: [Cr(VI)] = 20 μM, [I−] = 100 μM, pH = 3.0, and reaction temperature = 25 °C for aqueous phase reaction or –20 °C for frozen phase reaction](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_564_image_1.png "(a) Time profiles of Cr(VI) concentration, (b) absorbance changes, and (c) time profiles of I−, I2, and I3 − concentrations in aqueous and frozen solutions containing Cr(VI) and I−. Experimental conditions: [Cr(VI)] = 20 μM, [I−] = 100 μM, pH = 3.0, and reaction temperature = 25 °C for aqueous phase reaction or –20 °C for frozen phase reaction")
![(a) Optical image of a frozen Cr(VI) solution, (b) Raman spectra measured at the ice grain boundary (red circle) and ice crystal (black circle) in (a), and (c) Cr(VI) concentration distribution image of frozen Cr(VI) solution. Experimental conditions: [Cr(VI)] = 1 mM, pH = 3.0, and freezing temperature = 0 → −20 °C at a rate of −1.5 °C/min](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_565_image_267.png "(a) Optical image of a frozen Cr(VI) solution, (b) Raman spectra measured at the ice grain boundary (red circle) and ice crystal (black circle) in (a), and (c) Cr(VI) concentration distribution image of frozen Cr(VI) solution. Experimental conditions: [Cr(VI)] = 1 mM, pH = 3.0, and freezing temperature = 0 → −20 °C at a rate of −1.5 °C/min")
![Raman spectra measured in the ice grain boundary region of a frozen solution containing Cr(VI) and I−. Experimental conditions: [Cr(VI)] = 1 mM, [I−] = 1 mM, pH = 3.0, and freezing temperature = 0 → −20 °C at a rate of −1.5 °C/min. Reaction time is defined as the time after the temperature of the microscope stage has reached –20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_566_image_1.png "Raman spectra measured in the ice grain boundary region of a frozen solution containing Cr(VI) and I−. Experimental conditions: [Cr(VI)] = 1 mM, [I−] = 1 mM, pH = 3.0, and freezing temperature = 0 → −20 °C at a rate of −1.5 °C/min. Reaction time is defined as the time after the temperature of the microscope stage has reached –20 °C")
![Cr(VI) concentration distribution images of a frozen solution containing Cr(VI) and I −. Experimental conditions: [Cr(VI)] = 1 mM, [I−] = 1 mM, pH = 3.0, and freezing temperature = 0 → −20 °C at a rate of −1.5 °C/min. Reaction time is defined as the time after the temperature of the microscope stage has reached –20 °C](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_567_image_1.png "Cr(VI) concentration distribution images of a frozen solution containing Cr(VI) and I −. Experimental conditions: [Cr(VI)] = 1 mM, [I−] = 1 mM, pH = 3.0, and freezing temperature = 0 → −20 °C at a rate of −1.5 °C/min. Reaction time is defined as the time after the temperature of the microscope stage has reached –20 °C")
![Effect of I− concentration increase and/or pH decrease on Cr(VI) reduction. Experimental conditions: [Cr(VI)] = 20 μM, [I−] = 100 μM or 10 mM, pH = 3.0 or 1.3, reaction time = 2 h, and reaction temperature = 25 °C for aqueous phase reaction or –20 °C for frozen phase reaction](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_568_image_268.png "Effect of I− concentration increase and/or pH decrease on Cr(VI) reduction. Experimental conditions: [Cr(VI)] = 20 μM, [I−] = 100 μM or 10 mM, pH = 3.0 or 1.3, reaction time = 2 h, and reaction temperature = 25 °C for aqueous phase reaction or –20 °C for frozen phase reaction")
![Effect of (a) I− concentration, (b) pH, (c) temperature, and (d) freezing method on the Cr(VI) reduction efficiency. Experimental conditions: [Cr(VI)] = 20 μM, [I−] = 0−100 μM, pH = 2.0−6.0, reaction temperature = 25 ~ −196 °C, and reaction time = 2 h](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_569_image_269.png "Effect of (a) I− concentration, (b) pH, (c) temperature, and (d) freezing method on the Cr(VI) reduction efficiency. Experimental conditions: [Cr(VI)] = 20 μM, [I−] = 0−100 μM, pH = 2.0−6.0, reaction temperature = 25 ~ −196 °C, and reaction time = 2 h")
![Simultaneous (a) reduction of Cr(VI) and (b) production of I2 in the Cr(VI)-contaminated electroplating wastewater after I− addition and freezing. Experimental conditions: [Cr(VI)] = 20 μM in the diluted electroplating wastewater, [I−] = 100 μM, pH = 3.0, and reaction temperature = 25 °C for aqueous phase reaction or –20 °C for frozen phase reaction](https://nrms.kisti.re.kr/bitextimages/TRKO202300014483/TRKO202300014483_570_image_1.png "Simultaneous (a) reduction of Cr(VI) and (b) production of I2 in the Cr(VI)-contaminated electroplating wastewater after I− addition and freezing. Experimental conditions: [Cr(VI)] = 20 μM in the diluted electroplating wastewater, [I−] = 100 μM, pH = 3.0, and reaction temperature = 25 °C for aqueous phase reaction or –20 °C for frozen phase reaction")
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| 주관연구기관 | 한국해양연구원 부설 극지연구소 |
|---|---|
| 연구책임자 | 김기태 |
| 참여연구자 | 이준혁 , 김한우 , 김대영 , 이두형 , 김보미 , 도학원 , 이성구 , 박지수 , 이재일 , 유규철 , 김성한 , 이민경 , 이정은 , 박기태 , 김진형 , 강승현 , 김성한 , 조성미 , 남성진 , 정현영 , 김봄이 , Nguyen Quoc Anh , 한태욱 , 안용윤 , 남예원 , 노연호 , 김현철 , 서윤지 , 최철호 , 최원용 , 박문정 , 김정원 , 강헌 |
| 보고서유형 | 1단계보고서 |
| 발행국가 | 대한민국 |
| 언어 | 한국어 |
| 발행년월 | 2023-02 |
| 주관부처 | 해양수산부 Ministry of Oceans and Fisheries |
| 과제관리전문기관 | 한국해양연구원 부설 극지연구소 |
| 등록번호 | TRKO202300014483 |
| DB 구축일자 | 2023-09-19 |
| 키워드 | 얼음.미세구조.화학반응.할로겐.화학적 풍화.동결정화.ice.microstructure.chemical reaction.halogen.chemical weathering.freezing purification. |
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