含溴水臭氧化过程阴离子对溴酸盐生成的影响

为研究常见无机阴离子对含溴水臭氧化过程溴酸盐(Br O-3)生成的影响,本研究通过小试分别考察了不同质量浓度氯离子(Cl-)、碳酸氢根离子(HCO-3)和硫酸根离子(SO2-4)对Br O-3生成的影响,并结合反应过程臭氧衰减、中间产物次溴酸/次溴酸根离子(HOBr/OBr-)生成及总溴浓度变化情况,进一步分析了这3种无机阴离子对Br O-3生成的影响机制.结果表明,以60 min为例,Cl-质量浓度为3~150 mg·L-1的水样Br O-3生成量相对于未投加Cl-条件降低了8.8%~25.7%;反应20min时,SO2-4质量浓度从0 mg·L-1增至30 mg·L-1时,Br O-3生成量减少了63.9%;而当HCO-3质量浓度由0 mg·L-1上升至30 mg·L-1时,Br O-3生成量增加了6.4倍,其质量浓度超过30 mg·L-1,继续投加HCO-3对Br O-3生成量的促进作用提高不大.研究表明,在相同的臭氧投加量和相同的反应时间下,投加Cl-和SO2-4均能抑制臭氧化过程Br O-3的生成,而投加HCO-3能极大地促进Br O-3的生成.

Effects of Anions on Bromate Formation During Ozonation of Bromide-Containing Water

To study the effects of common inorganic anions on bromate formation during ozonation of bromide-containing water, the effects of different mass concentrations of Cl^-, HCO₃^-, and SO₄^2- on bromate formation were investigated in bench-scale test. The mechanisms of these three coexisting anions on bromate formation was analyzed based on the ozone decomposition, HOBr/OBr^- formation, and transformation of total bromine species. Our results showed that adding of 3-150 mg ·L^-1 Cl^- can reduce 8.8%-25.7% of bromate formation within 60 min. 63.9% of bromate would be decreased by increasing SO₄^2- concentration from 0 mg ·L^-1 to 30 mg ·L^-1 within 20 min. However, more than 6.4 times the mass concentrations of bromate were formed as HCO₃^- mass concentrations increased from 0 mg ·L^-1 to 30 mg ·L^-1 within 20 min. The production of bromate was slightly increased when HCO₃^- mass concentrations was above 30 mg ·L^-1. Under the condition of the same ozone dosage and reaction time, adding of Cl^- and SO₄^2- will inhibit the formation of bromate during ozonation, while adding of HCO₃^- significantly will increase the production of bromate.