Study On Decrement Of Heavy Metals In Wastewater By Electrochemical Method

With the rapid development of industry and agriculture,the use and emission of various heavy metals are increasing day by day,which has a serious impact on the environment,especially the water environment.On the one hand,due to heavy metal microbial toxicity will affect the biological treatment effect,in addition to most of the heavy metal in the water treatment process is transferred to the excess sludge,serious impact on resource utilization of sludge.Therefore,the separation and removal of heavy metals in waste water with high efficiency and the reduction of heavy metals content in sludge are the key problems in the study of wastewater treatment with heavy metals.Electrochemical remediation technology has the advantages of no need to add chemicals,less secondary pollution,and can control the flow direction of pollutants.It has important research value in pollution removal and environmental remediation.In this experiment,an electrochemical treatment unit was used to study the removal effect of heavy metals in water by electrochemical treatment.With manual configuration of Cu?Hg?Mn and Zn mixed heavy metal wastewater,using PbO2/Ti coated electrode as anode reaction,was investigated on the removal of heavy metal electrochemical factors of current density,initial pH,electrolyte concentration.The study shows that the best conditions for the treatment of mixed metals in the experiment are:current density is 10mA/cm2,initial pH 2.5-4.5,electrolyte concentration is 0.1mol/L,in this condition can achieve high removal efficiency of mixed metal;the different nature of the metal has the different removal rate,the four kinds of metal ion removal researched in the experiment is successively:Hg>Cu>Zn>Mn.Proper prolongation of the electrolysis time is beneficial to removal of Mn and Zn in the solution.The comparison of single element electrochemical treatment shows that the removal rate of different metals is different.Under similar conditions,the removal efficiency of single metal is obviously higher than that in mixed metal solution.When there exist many metals,the migration and deposition of different metals have a certain trend of competition.Dynamic analysis shows that,when the current density is 20mA/cm2,the initial pH is 2.53,and the electrolyte concentration is O.lmol/L,the reaction rate constant of Zn removal process is 0.6960min-1;the current density of 20mA/cm2,initial pH is 3.55,the electrolyte concentration is 0.2mol/L,the reaction rate constant of Mn removal process is 0.4901min-1,both follow first order kinetics.