真空紫外/氯处理饮用水典型致嗅物质

为有效去除常规水处理工艺难以去除的典型致嗅物质二甲基异莰醇（2-MIB）和土臭素（GSM），采用真空紫外/氯高级氧化技术，探讨该技术降解致嗅物质的效能，研究在不同紫外光强、氯浓度、pH、重碳酸盐浓度、腐殖酸浓度条件下致嗅物质的降解效果，分析羟基自由基在致嗅物质降解中起到的作用，目标物浓度采用吹扫捕集-气质联用法（GC/MS）测定.结果表明，真空紫外/氯高级氧化技术可以有效去除饮用水典型致嗅物质，相比紫外/氯高级氧化技术而言，在30 min内2-MIB和GSM的去除率分别提高15%和8%；随着氯浓度和紫外光强度的增加，致嗅物质的降解速率加快；在弱酸性条件下，致嗅物质的去除效果明显，在pH为5时，2-MIB和GSM的去除率在反应10 min后分别可以达到95%和96%；水体中重碳酸盐和腐殖酸的存在，竞争消耗反应体系中的自由基，对致嗅物质的降解起到抑制作用；在反应体系中投加1 mmol·L^-1羟基自由基抑制剂叔丁醇后，2-MIB和GSM的去除率下降明显，分别下降40%和31%，表明羟基自由基在致嗅物质的去除中起到主要作用.

Removing Typical Odorants in Drinking Water by Vacuum Ultraviolet Combined with Chlorine

For the effective removal of two typical odorants found in drinking water, 2-methylisoborneol (2-MIB) and geosmin (GSM), which cannot be effectively removed by the conventional water treatment processes, the advanced oxidation process of vacuum ultraviolet combined with chlorine (VUV/chlorine) was studied. The efficiency of this technology in the removal of these typical odorants was investigated; the effects of ultraviolet intensity, chlorine concentration, pH, bicarbonate concentration, and humic acid concentration on the degradation of these typical odorants were examined, and the role of hydroxyl radicals (·OH) in the degradation of these typical odorants was analyzed. The purge and trap method coupled with gas chromatography and mass spectrometry (GC/MS) was used to determine the concentrations of the typical odorants. The results showed that the VUV/chlorine technology removed typical odorants effectively, and the removal rates of 2-MIB and GSM increased by 15% and 8%, respectively, in 30 minutes, compared with that by the UV/chlorine technology. With the increase in chlorine concentration and ultraviolet intensity, the degradation rates of the typical odorants was accelerated. The removal of the typical odorants was obvious under weak acid condition, and the removal rates of 2-MIB and GSM reached 95% and 96%, respectively, in 10 minutes under the condition of pH 5. Bicarbonate and humic acid competed with free radicals in the reaction system to inhibit the degradation of the typical odorants. The removal rates of 2-MIB and GSM decreased appreciably by 40% and 31%, respectively, when 1 mmol·L^-1 tert-butanol was added to the reaction mixture, which indicated that hydroxyl radicals (·OH) played a major role in the removal of these typical odorants.