Photoelectrocatalytic Degradation Of 2-Naphthol ^Cr（Ⅵ） Simulation Wastewater Using Sulfur-Doped TiO₂ Catalyst

With the merits of photochemical stability, non-toxicity,low cost,and so on, Ti O2 has given high hopes in the areas of Organic matter or heavy metal waste water treatment. However, theareas were rarely involved in organic matter and heavy metal combination of complex system research, and the electrochemical assisted photocatalytic collaborative research is seldom reported. In this experiment,sulfur-doped titanium dioxide was prepared by a simple sol-gel method using tetrabutyl titanate and potassium persulfate as precursors.Photocatalytic degradation of 2-naphthol and reduction of Cr(VI) was studied by using sulfur-doped Ti O2 as photo catalyst and visible light as light source. The main eontents of experiment were as follows:XRD, SEM, FTIR and particles size analysis were applied to characterize the sulfur doped Ti O2 and its preparation process optimization(the calcination temperature and the sulfur-dopant amount).The results of characterization showed that S/Ti O2 has been successfully synthesized. When the calcine temperature was 400 ℃, the sulfur-dopant amount was 4%,the S/Ti O2 visible-light photocatalytic activity was the best.these three factors involved in this experiment were p H, initial concentration of 2-naphthol solution and S/Ti O2 dosage in photocatalytic oxidation degradation of β- naphthol. The optimal conditions of treatment of 2-naphthol were found by means of orthogonal test:: the proper dosage of sulfur-doped Ti O2 catalyst is 2.0g/L,concentration of2-naphthol is 14 mg /L and p H =7,T =30℃,the photocatalytic degradation rate of 2-naphthol could achieve 99.8%. The oxidation of 2-naphthol followed the pseudo first order reaction kinetics.Photocatalytic degradation of 2-naphthol and reduction of Cr(VI)was studied by using sulfur-doped Ti O2 as photo catalyst and visible light as light source. Comparing different mass ratio of Cr(VI) and β-naphthol the synergistic effect of composite system.In Cr( VI)~2-naphthol compound system, 2-naphthol and Cr(VI) were more efficiently eliminated than in the single 2-naphthol or Cr(VI)system. The reduction of Cr(VI) and the oxidation of 2-naphthol produced a synergistic effect. The photocatalytic reduction of Cr(VI) and oxidation of 2-naphthol followed the pseudo first order reaction kinetics.Degradation of 2-naphthol simulated wastewater was studied by using the self-made sulfur-doped Ti O2 photoelectrocatalysis.The influences of bias potential,cnocentration of Na Cl,initial concentration of 2-naphthol, p H and reaction time on the photoelectrocatalytic activity were investigated. The optimal conditions of treatment of2-naphthol were found by means of uniform test: When the proper bias potential was 50 V,cnocentration of Na Cl was 0.6g/L,concentration of 2-naphthol was 20 mg /L,p H=7and reaction time was 40 min,the photoelectrocatalytic degradation rate of 2-naphthol could achieve 98%.