Photocatalytic oxidation in the presence of Fe-doped, Zn-doped or Fe-Zn co-doped $TiO_2$ was used to effectively decompose humic acids (HAs) in water. The highest HAs removal efficiency (65.7%) was achieved in the presence of $500^{\circ}C$ calcined 0.0010% Fe-Zn co-doped ...
Photocatalytic oxidation in the presence of Fe-doped, Zn-doped or Fe-Zn co-doped $TiO_2$ was used to effectively decompose humic acids (HAs) in water. The highest HAs removal efficiency (65.7%) was achieved in the presence of $500^{\circ}C$ calcined 0.0010% Fe-Zn co-doped $TiO_2$ with the Fe:Zn ratio of 3:2. The initial solution pH value, inorganic cations and anions also affected the catalyst photocatalytic ability. The HAs removal for the initial pH of 2 was the highest, and for the pH of 6 was the lowest. The photocatalytic oxidation of HAs was enhanced with the increase of the $Ca^{2+}$ or $Mg^{2+}$ concentration, and reduced when concentrations of some anions increased. The inhibition order of the anions on $TiO_2$ photocatalytic activities was $CO{_3}^{2-}$ > $HCO_3{^-}$ > $Cl^-$, but a slightly promotion was achieved when $SO{_4}^{2-}$ was added. Total organic carbon (TOC) removal was used to evaluate the actual HAs mineralization degree caused by the $500^{\circ}C$ calcined 0.0010% Fe-Zn (3:2) co-doped $TiO_2$. For tap water added with HAs, the $UV_{254}$ and TOC removal rates were 57.2% and 49.9%, respectively. The $UV_{254}$ removal efficiency was higher than that of TOC because of the generation of intermediates that could significantly reduce the $UV_{254}$, but not the TOC.
Photocatalytic oxidation in the presence of Fe-doped, Zn-doped or Fe-Zn co-doped $TiO_2$ was used to effectively decompose humic acids (HAs) in water. The highest HAs removal efficiency (65.7%) was achieved in the presence of $500^{\circ}C$ calcined 0.0010% Fe-Zn co-doped $TiO_2$ with the Fe:Zn ratio of 3:2. The initial solution pH value, inorganic cations and anions also affected the catalyst photocatalytic ability. The HAs removal for the initial pH of 2 was the highest, and for the pH of 6 was the lowest. The photocatalytic oxidation of HAs was enhanced with the increase of the $Ca^{2+}$ or $Mg^{2+}$ concentration, and reduced when concentrations of some anions increased. The inhibition order of the anions on $TiO_2$ photocatalytic activities was $CO{_3}^{2-}$ > $HCO_3{^-}$ > $Cl^-$, but a slightly promotion was achieved when $SO{_4}^{2-}$ was added. Total organic carbon (TOC) removal was used to evaluate the actual HAs mineralization degree caused by the $500^{\circ}C$ calcined 0.0010% Fe-Zn (3:2) co-doped $TiO_2$. For tap water added with HAs, the $UV_{254}$ and TOC removal rates were 57.2% and 49.9%, respectively. The $UV_{254}$ removal efficiency was higher than that of TOC because of the generation of intermediates that could significantly reduce the $UV_{254}$, but not the TOC.
* AI 자동 식별 결과로 적합하지 않은 문장이 있을 수 있으니, 이용에 유의하시기 바랍니다.
가설 설정
, and (d) the effect of tap water compared to Milli-Q water as solvent.
제안 방법
As it is known that TiO2 in anatase phase shows better photocatalytic activity, the XRD analysis was conducted. With increasing doping amount of Fe3+ or Zn2+, the diffraction peaks belonging to the (101) peak of anatase phase (2θ at about 25.
, were also investigated using the optimized catalyst. Different concentrations (0.5, 1.0, 1.5, 2.0 and 2.5 mmol/L) of NaHCO3, Na2CO3, Na2SO4, NaCl, MgCl2 and CaCl2, similar with the concentration level in natural water, were added into the water with the initial pH value of 7.0, and the HAs concentrations were determined every 5 min.
The BET surface areas (SBET) of the samples were determined by Quadrasorb SI-MP apparatus (Quantachrome Instrument, USA). Diffuse reflectance spectroscopy (DRS) was performed using a HITACHI U-3010 UV-Vis scanning spectrophotometer (Tokyo, Japan).
5 mg/L, respectively. TOC measurements were performed by the spectrophotometer using low-range TOC ampoules (Hach Chemical, USA).
TOC removal was used to evaluate the actual HAs mineralization degree in tap water caused by the 500°C calcined 0.0010% Fe-Zn (3:2) co-doped TiO2 (Fig. 6).
Extensive research has been devoted to the removal of HAs by photocatalyzed oxidation processes using semiconducting metal oxide nanoparticles like TiO2 [7]. The research efforts in this area are mainly based on assessing the factors that describe the kinetics and mechanistic pathways of photocatalytic removal of HAs.
대상 데이터
The photocatalytic reactor was a cylindrical glass column with a diameter and height of 60 and 850 mm, respectively. A 37 W low-pressure mercury vapor lamp (Φ22 mm × 790 mm; Beijing Haili Lighting Equipment Company, China) with UV wavelength of about 254 nm and UV radiation intensity of about 110 μW/cm2 was found inside the column.
성능/효과
4 shows that a beneficial effect of cations in water on the degradation of HAs was achieved. At time of 120 min of irradiation, 72.1%, 75.5%, 78.1%, 81.9% and 83.5% of degradations with Fe-Zn co-doped TiO2 were observed for 0.5, 1.0, 1.5, 2.0 and 2.5 mmol/L of Ca2+ in neutral medium, whereas 65.7% degradations occurred in medium without Ca2+. The HAs removal efficiencies were 70.
However, when SO42- was added at the concentrations of 0.5, 1.0, 1.5, 2.0 and 2.5 mmol/L, a slight increase for HAs removal was observed, and the HAs removal efficiencies were 66.8%, 67.6%, 68.2%, 69.0% and 69.6%, respectively.
This was because the phase transformation temperature reduced after doping [18]. In addition, with the increase of the calcination temperature, the diffraction peak of anatase appeared stronger and sharper, indicating that better crystallites were formed, and the intensity of the rutile phase increased when the calcination temperature increased because of the transformation of TiO2 from anatase phase to rutile phase.
In this study, the optimized photocatalyst (500°C calcined 0.0010% Fe-Zn co-doped TiO2 with the Fe:Zn ratioratio of 3:2) was used, and the HAs removal efficiencies at different pH value, cation or anion concentrations were detected.
The 500°C calcined 0.0010% Fe-Zn co-doped TiO2 with the Fe:Zn ratioratio of 3:2 showed the highest catalytic activity, with the HAs removal efficiency of 65.7%.
7% degradations occurred in medium without Ca2+. The HAs removal efficiencies were 70.4%, 73.0%, 74.9%, 76.7% and 79.5% for the medium with Mg2+ concentration of 0.5, 1.0, 1.5, 2.0 and 2.5 mmol/L, respectively. The photocatalytic oxidation of HAs was enhanced with the increase of the Ca2+ or Mg2+ concentration.
The optimal calcination temperature was 500°C for both Fe-doped and Zn-doped TiO2, and the best photocatalytic activities were achieved when the Fe3+ or Zn2+ doping amount was 0.0010%, corresponding to the HAs removal efficiencies of 57.4% and 53.7%, respectively.
참고문헌 (25)
Ghouas H, Haddou B, Kameche M, Derriche Z, Gourdon C. Extraction of humic acid by coacervate: Investigation of direct and back processes. J. Hazard. Mater. 2012;205-206:171-178.
Wiszniowski J, Robert D, Surmacz-Gorska J, Miksch K, Malato S, Weber JV. Solar photocatalytic degradation of humic acids as a model of organic compounds of landfill leachate in pilot-plant experiments: Influence of inorganic salts. Appl. Catal. B. Environ. 2004;53:127-137.
Wei MC, Wang KS, Hsiao TE, et al. Effects of UV irradiation on humic acid removal by ozonation, Fenton and $Fe^0$ /air treatment: THMFP and biotoxicity evaluation. J. Hazard. Mater. 2011;195:324-331.
Chang MY, Juang RS. Adsorption of tannic acid, humic acid, and dyes from water using the composite of chitosan and activated clay. J. Colloid Interface Sci. 2004;278:18-25.
Pang YL, Abdullah AZ. $Fe^{3+}$ doped $TiO_2$ nanotubes for combined adsorption-sonocatalytic degradation of real textile wastewater. Appl. Catal. B. Environ. 2013;129:473-481.
Sun L, Li J, Wang CL, Li SF, Chen HB, Lin CJ. An electrochemical strategy of doping $Fe^{3+}$ into $TiO_2$ nanotube array films for enhancement in photocatalytic activity. Sol. Energ. Mat. Sol. C. 2009;93:1875-1880.
Hou D, Goei R, Wang X, Wang P, Lim TT. Preparation of carbon-sensitized and Fe-Er codoped $TiO_2$ with response surface methodology for bisphenol A photocatalytic degradation under visible-light irradiation. Appl. Catal. B. Environ. 2012;126:121-133.
Yuan R, Zhou B, Hua D, Shi C. Enhanced photocatalytic degradation of humic acids using Al and Fe co-doped $TiO_2$ nanotubes under UV-ozonation for drinking water purification. J. Hazard. Mater. 2013;262:527-538.
Naraginti S, Thejaswini TVL, Prabhakaran D, Sivakumar A, Satyanarayana VS, Arun Prasad AS. Enhanced photo-catalytic activity of Sr and Ag co-doped $TiO_2$ nanoparticles for the degradation of Direct Green-6 and Reactive Blue-160 under UV & visible light. Spectrochim. Acta. A. 2015;149:571-579.
Yuan Z, Jia Z, Zhang L. Influence of co-doping of Zn(II) + Fe(III) on the photocatalytic activity of $TiO_2$ for phenol degradation. Mater. Chem. Phys. 2002;73:323-326.
Rincon AG, Pulgarin C. Effect of pH, inorganic ions, organic matter and $H_2O_2$ on E. coli K12 photocatalytic inactivation by $TiO_2$ : Implications in solar water disinfection. Appl. Catal. B. Environ. 2004;51:283-302.
Sanchez-Dominguez M, Morales-Mendoza G, Rodriguez-Vargas MJ, et al. Synthesis of Zn-doped $TiO_2$ nanoparticles by the novel oil-in-water (O/W) microemulsion method and their use for the photocatalytic degradation of phenol. J. Environ. Chem. Eng. 2015;3:3037-3047.
Yuan R, Zhou B. Effect of ion (Al, Fe and Zn) co-doped $TiO_2$ nanotubes on photocatalytic degradation of humic acids under UV/ozonation for drinking water purification. Water Sci. Technol. Water Supply 2016;16:237-244.
Xiao J, Xie Y, Cao H, Nawaz F, Zhang S, Wang Y. Disparate roles of doped metal ions in promoting surface oxidation of $TiO_2$ photocatalysis. J. Photochem. Photobiol. A. 2016;315:59-66.
Li X, Zou X, Qu Z, Zhao Q, Wang L. Photocatalytic degradation of gaseous toluene over Ag-doping $TiO_2$ nanotube powder prepared by anodization coupled with impregnation method. Chemosphere 2011;83:674-679.
Rauf MA, Meetani MA, Hisaindee S. An overview on the photocatalytic degradation of azo dyes in the presence of $TiO_2$ doped with selective transition metals. Desalination 2011;276:13-27.
Islam MM, Basu S. Effect of morphology and pH on (photo) electrochemical degradation of methyl orange using $TiO_2$ /Ti mesh photocathode under visible light. J. Environ. Chem. Eng. 2015;3:2323-2330.
Selvam K, Muruganandham M, Muthuvel I, Swaminathan M. The influence of inorganic oxidants and metal ions on semiconductor sensitized photodegradation of 4-fluorophenol. Chem. Eng. J. 2007;128:51-57.
Wang KH, Hsieh YH, Wu CH, Chang CY. The pH and anion effects on the heterogeneous photocatalytic degradation of o-methylbenzoic acid in $TiO_2$ aqueous suspension. Chemosphere 2000;40:389-394.
Wang Y, Lu K, Feng C. Influence of inorganic anions and organic additives on photocatalytic degradation of methyl orange with supported polyoxometalates as photocatalyst. J. Rare Earth. 2013;31:360-365.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.