Study On The Control Strategies Of Dichloroacetonitrile The Disinfection By-product In Drinking Water

Disinfection is one of the necessary steps to produce drinkable water.But in the process of disinfection,the disinfection by-products will pose serious threat to people's health.Therefore,it is very important to study the control strategies of disinfection by-products of drinking water.This experiment will adopt the method of liquid-liquid extraction?LLE?-gas chromatograph?GC?in which dichloroacetonitrile and1,2-dibromopropane will be the target object and internal standard substance,methyl tert-butyl ether?MTBE?as the extraction agent to establish a DCAN detection and analysis method.The removal effect,influence factors,reaction mechanism and reaction kinetics of powder activated carbon?PAC?adsorption,K₂FeO₄ oxidation and Fe/Cu catalytic reduction technology were discussed respectively.It was found that the standard deviation?RSD?of DCAN was between 94.6¹03.8%,and the relative standard deviation?RSD?was between 1.22⁶.53%,and the minimum detection limit was between 0.19².04?g/L,which indicated the accuracy and precision were higher.The process of adsorption of DCAN by powder activated carbon?PAC?is divided into three stages:rapid stage,slow stage and dynamic equilibrium stage.Under the test conditions,when the initial mass concentration of DCAN was 40?g/L,the removal rate of PAC was gradually increased with the increase of PAC.The removal rate of DCAN increases rapidly when the amount of PAC is increased from 0.1 g/L to 0.6g/L.After that,it continues to increase the amount of PAC,and the DCAN removal rate increases slowly.With the increase of initial concentration,PAC adsorption quantity of DCAN increases gradually,but the removal rate of DCAN reduce gradually.With the increase of temperature,PAC adsorption effect of DCAN also increased.The PAC's removal rate for DCAN is decreasing as the pH increases.The process of the PAC adsorb DCAN is consistent with a secondary adsorption dynamics pattern.When the initial concentration of DCAN was 40?g/L,and the dosage of potassium ferrate was 0.04 g/L,the removal rate of potassium ferrate on DCAN gradually increased with the increase of time.After 30 min,the removal rate reached 64.82%and then kept stable.The removal rate of DCAN was greatly influenced by the amount of potassium ferrate.When the amount of potassium ferrate was increased from 0.01 g/L to 0.08 g/L,the removal rate of DCAN was increased from 48.4%to 88.4%.The effect of pH on potassium ferrate removal DCAN was significant.The removal rate of DCAN increased with the increase of pH in the range of 4.5⁶.5.When the pH was 6.5,the removal rate of DCAN reached 65.14%after 30min.The process of DCAN degradation of potassium ferrate was consistent with the first order reaction kinetics.For DCAN solution with a concentration of 40?g/L,the removal effect of single Fe on DCAN was poor,after 180 min,the removal rate of DCAN was 55.85%.The Fe/Cu mixture can remove DCAN better,and when the quality ratio of Fe/Cu is 10:1,the removal rate of DCAN is88.4%after 180 min.The removal efficiency of Fe/Cu for DCAN increases as the addition amount of Fe/Cu is increased.When Fe/Cu?mass ratio10:1?increased from 2 g/L to 14 g/L,the removal rate increased from72.3%to 90.6%.With the increase of temperature,the removal rate of DCAN is improved.The removal rate of DCAN increases with increasing initial concentration of DCAN.When the initial concentration of DCAN is increased from 10?g/L to 30?g/L,the removal rate of DCAN increases from 85.5%to 89.4%.When the initial concentration of DCAN increases to30?g/L,the removal rate is basically stable.