二氧化氯杀藻无机副产物亚氯酸盐生成规律研究

研究了不同二氧化氯投加量、接触时间、pH值下二氧化氯杀藻中亚氯酸盐的生成规律及其他水质条件(藻初始质量浓度、有机物和氨氮)对亚氯酸盐生成的影响。结果表明,亚氯酸盐生成量随着二氧化氯投加量的增大和时间的延长而增大。放置2 h,生成的亚氯酸盐占二氧化氯初始投加量的10%~30%。二氧化氯杀藻的水样放置时间越长,开始生成亚氯酸盐的pH值就越低。放置30 min时生成亚氯酸盐的起始pH值为6,放置70 min时起始pH值为3.9。在酸性条件下,亚氯酸盐的生成量随pH值增大而增大;而从中性到碱性,亚氯酸盐增加缓慢。藻初始叶绿素a的质量浓度超过14.93μg/L时,亚氯酸盐的生成量随藻初始质量浓度的增大而增大。有机物促进了亚氯酸盐的生成,但亚氯酸盐的生成量并没有随有机物质量浓度的增加而增加。增大氨氮质量浓度,亚氯酸盐的生成量有降低的趋势。

Formation regularity of the inorganic by-product chlorite in killing algae with chlorine dioxide

This paper aims to study the generating regularity of the inorganic by-product chlorite in the algae preoxidation with chlorine dioxide in drinking water processing.For this purpose,we have made an investigation over the generating regularity of chlorite under the conditions of different dosages of chlorine dioxide,contact time and pH.We have also studied the other influencing factors related to water quality,such as algal initial concentration,organic substances and ammonia nitrogen concentration on the generation of the by-product chlorite.The testing and investigation results show that the by-product chlorite increases with the increase of the dosage of chlorine dioxide.In addition,it is found that time is the key factor to influence the generation of chlorite.Actually,large amounts of chlorite would be resulted in 30 minutes.Two hours later,we may find that there would be generated chlorite which is 10 to 30 percent of chlorine dioxide,with an initial pH value beginning to generate the chlorite.The longer the contact time,the lower the initial pH would be.30 minutes later after a 10 minute reaction,the initial pH value would increase to 6.However,70 minutes later,the initial pH value would turn to be 3.9.Furthermore,the chlorite would gradually increase in the acidity condition while the pH value would change from low to high.Nevertheless,when the pH changes from neutral to alkalinity,little increase would be found of the chlorite in final analysis.But,when the algal chlorophyll-a concentration remains below 14.93 μg/L,no variation of the amount of by-product chlorite could be found with the initial algal concentration.However,when the algal chlorophyll-a concentration is greater than 14.93 μg/L,the chlorite tends to increase with the increase of the algal initial concentration.Though the organic matter is likely to promote the formation of chlorite,the chlorite wouldn’t be found increasing with the increase of the concentration of the organic matter,which demonstrates a decreasing trend with the increase of the ammonia nitrogen concentration.And the residual chlorine dioxide is found decreasing with the time prolonging in the process of the formation of chlorite.Based on the regression analysis of the experimental data,the relation between the residual chlorine dioxide and the time to be elapsed seems to be a function of the power series in the generation of the by-product chlorite.