Fe^(3+)和Cu^(2+)对饮用水氯消毒副产物三卤甲烷形成的影响

Effects of Fe^(3+) and Cu^(2+) on formation of THMs during disinfection of drinking water by chlorine

为了研究水中存在Br-的情况下,Fe3+和Cu2+对三卤甲烷(THMs)的生成及CHCl3、CHBr Cl2、CHBr2Cl、CHBr34种消毒副产物相对分布的影响,以腐殖酸模拟氯消毒过程中的前体物进行实验。结果表明,在p H为6、7和9 3种条件下,Fe3+抑制了THMs的生成,p H=6时只有CHCl3生成量随着Fe3+浓度的增加逐渐减少,其余3种消毒副产物均在增加,p H=7时4种消毒副产物浓度均减小并在Fe3+浓度为2 mg/L时生成量最低,p H=9时的生成趋势与p H=6时类似。Cu2+能促进THMs的生成,在p H为6、7和9时,当加入0.5 mg/L Cu2+时,THMs总量分别增加了16.7%、22.6%和2.5%,随着p H增加,THMs总量增加。在3种p H环境中,Cu2+对THMs生成的影响大于Fe3+,在偏酸性环境中,Fe3+影响THMs生成,产生的致癌风险高,当金属离子浓度为2.5 mg/L时,致癌风险相差最高为15%,在中性和偏碱性环境中,Cu2+影响THMs生成,产生的致癌风险高。

Effects of ferric and copper ions on the formation and distribution of( THMs) such as CHCl3,CHBr Cl2,CHBr2,and CHBr3 were investigated in the presence of bromide ion. Humic acid was used as disinfection by-product( DBP) model precursors and a series of experiments were conducted. The results showed that Fe3 +inhibited the formation of THMs when p H values were 6,7,and 9. Only the production of CHCl3 decreased,while the other three DBPs increased with the increasing of Fe3 +when p H was 6. Four kinds of THMs decreased with Fe3 +increased when p H was 7. The generate trends were similar when p H values of 6 and 9. Cu2 +can promote the formation of THMs. When 0. 5mg / L Cu2 +was added to solution while p H values of 6,7 and 9,THMs increased by 16. 7%,22. 6% and 2. 5%,respectively. The impact of Cu2 +on THMs was larger than Fe3 +. Cancer risk of THMs in drinking water was high when p H was 6 in the presence of Fe3 +. Effect of Cu2 +on cancer risk in drinking water was higher than Fe3 +when p H values were 7 and 9.