Mechanism of treatment and remediation of synthetic Cu2+ polluted water body by membrane and electro-winning combination process was investigated.The influences of electrolysis voltage,pH,and electrolysis time on the metal recovery effciencies were studied.Relationship between trans-membrane pressure drop(△P),additions ratio,initial Cu2+ concentration on operating effciency,stability of membrane and the possibility of water reuse were also investigated.The morphology of membrane and electrodes were observed using scanning electron microscopy(SEM),the composition of surface deposits was ascertained using combined energy dispersive X-ray spectroscopy(EDX) and atomic absorption spectrophotometer.The results showed that using low pressure reverse osmosis(LPRO),Cu2+ concentration could increase from 20 to 100 mg/L or even higher in concentrated solutions and permeate water conductivity could be less than 20 μS/cm.The addition of sodium dodecy/sulfate sodium dodecyl sulfate improved Cu2+ removal effciency,while EDTA had little side influence.In electro-reduction process,using plante electrode cell,Cu2+ concentration could be further reduced to 5 mg/L,and the average current effciency ranged from 9% to 40%.Using 3D electrolysis treatment,Cu2+ concentration could be reduced to 0.5 mg/L with a current effciency range 60%-70%.
With the rapid development of rare earth industry in China,high NH3-N and high salts wastewater generated in rare earth manufacture process had caused serious environment pollution especially for surrounding water body.Traditional treatment processes were either incapable of reducing pollutants concentration to the levels regulated by law or prohibitively expensive and difficult to operate.In this paper,a hybrid process which integrated air stripping pretreatment and low pressure reverse osmosis(LPRO) was proposed to treat this wastewater containing high ammonia and salt.Mechanism of treatment and remediation of ammonia and salt polluted water body was investigated.Influences of temperature,pH,and air stripping time on removal ratio of ammonia efficiencies were also discussed.Relationship among trans-membrane pressure drop(ΔP),additions ratio,stability of membrane and the possibility of water reuse were studied.The results showed that removal ratio of ammonia after LPRO desalination process could reach up to 98%,fluoride amounted to more than 99% and desalt efficiencies reached up to 95%,and stripped gas ammonia could be effectively recovered.Water quality had been improved significantly to meet reuse or discharge standards.
