The Treatment Of Copper-containing Wastewater By Microelectrolysis-fluidized Bed Elctrode Coupled Method

As the increasingly growing of domestic industry including mining, metallurgy, chemical producing, dyeing, agrichemicals, forage industry, as well as agriculture, environment problems like heavy metal pollution events became more and more severe and often, tasks on heavy-metal-polluted water had drawn more and more attention.To address heavy-metal pollution throughtout the country, various revelent policy and law were launched trying to control the heavy metal pollution, especially to the discharge of heavy-metal-polluted water, which is often contributed by domestic industry. However present treatment measures to heavy metal pollution is eather too low in efficiency or too much in byproducts generation, which is far from meeting the present requirement for environment protection in China. Investigation and study on a new effcient treatment technology to heavy metal is high in practical signficance and application value in present China. Based on the previous study, this paper emphasized on the micro-electrolysis fluidized bed electrode couplinge method to address heavy-meatl-polluted water.In the experiment, the nature of solid-liquid fluidization of granular iron-carbon packing in fluidized bed was studied, showing the minimum fluidization velocity of packing growed with the mean particle diameter of pellet, particles with diameter of 0.55m has a minimum fluidization velocity of 23mm/s.In the experiment, the micro-electrolysis fluidized bed and micro-electrolysis fluidized bed electrode coupling methods were applied to treat simulated copper-polluted water, pH value, reaction time, voltage and flow velocity were investigated as well to determine their impacts on treating results, showing that all reactions conformed to the first-order reaction kinetics model, for the micro-electrolysis fluidized bed method, the best reaction condition is:copper ion concentration 100mg/L, reaction time 30min, flow velocity 29mm/s and initial pH 4; for the micro-electrolysis fluidized bed electrode coupling method:copper ion concentration 100mg/L, reaction time 30min, flow velocity 22mm/s, voltage 12V and initial pH 4. The micro-electrolysis fluidized bed gradually loose its effectiveness after continuous 50h treatment to copper-polluted water and the removal rate would go down to below 90%. While the micro-electrolysis fluidized bed electrode coupling method prolonged this time period to 60h, which is more in penetration time.In experiment the capacity and efficiency of 5 methods, which are micro-electrolysis fluidized bed electrode coupling, single micro-electrolysis, single electrolysis, electrolysis fixed bed micro-electro lysis coupling and micro-electrolysis fluidized bed methods were compared under their best reaction conditions, showing that micro-electrolysis fluidized bed electrode coupling method was superior to other 4 methods, and the micro-electrolysis fluidized bed method is better than single micro-electrolysis method and single electrolysis method. The apparent rate constant of micro-electrolysis fluidized bed electrode coupling method reached as high as Kobs=0.25845, which is the 2.52 and 7.65 times of single micro-electrolysis method and single electrolysis, respectively, and the the efficiency and capacity of micro-electrolysis fluidized bed eletrode coupling method is more than the simple combination of single micro-electro lysis method and single electrolysis method.Under the best reaction condition, applying the micro-eletrolysis fluidized bed electrode coupling method to treat the discahrge water of CHALCO Yunnan Copper Co., Ltd branch for 30min, the residual content of Cu, Zn, Cd and Pb in treated water were 3.128 mg/L,16.2 mg/L,1.92 mg/L and 0.118 mg/L, respectively, removal rate were 99.7%, 95.8%,94.3% and 91.9%. And through the cobination of micro-eletrolysis fluidized bed electrode coupling method and flcculation and sedimentation method, the residual ion concentration of Cu, Zn, Cd and Pb were all able to meet the first-class standard in the Integarated Wastewater Discharge Standard, which were 0.5 mg/L,2 mg/L,0.1 mg/L and 1 mg/L, respectively.