海水基质成分对紫外线去除游离氯和游离溴的影响

Effect of water matrix components in seawater on ultraviolet removal of free chlorine and free bromine

紫外线照射可以去除反渗透工艺中的游离氯和游离溴,但是海水基质成分对于去除效果的影响尚不清晰.为解决上述问题,在低压紫外照射下测定了游离氯和游离溴的浓度变化,计算了分解速率常数,分析了水中pH、无机阴离子和腐殖酸对其分解速率的影响.结果表明,随着pH的降低,游离氯和游离溴的分解速率均升高,且pH对游离溴分解速率的影响更大;无机阴离子中Cl^(−)能够抑制游离氯的分解而促进游离溴的分解,NO_(3)^(-)能够促进游离氯的分解而抑制游离溴的分解;水中腐殖酸在低浓度时抑制游离氯和游离溴的分解,在高浓度时促进分解,对游离溴的促进作用更强.研究结果可以为反渗透系统中紫外线去除游离氯和游离溴的工艺优化提供数据参考.

Ultraviolet irradiation is capable of removing free chlorine and free bromine in reverse osmosis process,but the effect of seawater matrix components on the removal is still unclear.In this study,the concentration changes of free chlorine and free bromine under low-pressure UV irradiation were monitored and the decomposition rate constants were calculated.The effects of pH,inorganic anions and humic acid on the decomposition rate were investigated.The results showed that the decomposition rates of free chlorine and free bromine increased with the decrease of pH,and pH posed a greater effect on the decomposition rates of free bromine.Chloride ion inhibited the decomposition of free chlorine while enhanced the decomposition of free bromine.However,nitrate improved the decomposition of free chlorine while suppressed the decomposition of free bromine.Low concentration of humic acid presented inhibition on the decomposition of free chlorine and free bromine,while high concentration of humic acid stimulated their decomposition,especially free bromine.This study provided data support for the design of ultraviolet process for the removal of free chlorine and free bromine in reverse osmosis system.