| Over the years,pollution incidents arised by heavy metals such as copper,chromium,cadmium occur frequently throughout China.Non-ferrous metal smelting consumes a lot of water resources.As being an important part of nonferrous metal smelting,copper smelting generates grate amount of wastewater,causing great harm to environment and human.In order to solve the above problems,pulse alternating current(PAC)catalytic wastewater treatment mobile system was firstly designed in this paper.Through applying double electrode iron wastewater treatment of heavy metal copper ion electric flocculation and optimizing the raw water pH value,current density,processing time,wastewater flow rate conditions and number of reactors in series,the copper in the wastewater was efficiently removed.The purpose of reducing energy consumption was gained by using the developed process.The experimental results are obtained as.follows:(1)A novel reactor of copper wastewater treatment was developed using double iron electrodes and applying PAC current(4 V 1000 Hz and 20%pulse duty factor).The positive and negative electrodes were alternately changed in order to improve the efficiency of flocculation,reduce the polarization of double iron electrodes and prevent the double iron electrodes from passivation.(2)The copper in effluent was reduced to ～0.118 mg·dm-3 through electrocoagulation of pH 7.8～8 wastewater containing 100 mg dm-3 copper in the four-series reactor,applying PAC current density of 40 μA gFe-1,controlling the flow rate of 3 dm3 min-1 and at the room temperature(20-25℃).The copper residue in the effluent was far less than the GB standard requirement of<0.3 mg·dm-3 from GB21900-2008.(3)A large amount of copper was adsorbed on the surface of electrocoagulations.The cellular morphology with projections was more conducive to adsorb copper hydroxide.The elements of coagulations determined were mainly O,Fe and Cu.The more copper was removed by PAC coagulation technique than chemical flocculation technique.(4)The elaborate nanostructure of the electrocoagulations produced by PAC current(4 V 1000 Hz and 20%pulse duty factor)was more conducive to adsorb copper in the wastewater.The copper in wastewater was removed through flocculation from adsorption of ferrum collosol and electrodeposition of copper on double iron electrodes. |
