Studies On The Treatment Of Electroplating Wastewater Containing Nickel Ions With Ceramic Membranes

Ceramic microfiltration membranes was used to microfiltrate impure electroplating wastewater containing nickel ions, and the effect of operating parameter, concentration experiment, membrane flux recovery and the industrial design were investigated respectively. This work contributed to development of ceramic microfiltration membrane technology in the application of electroplating wastewater containing nickel ions.The microfiltration processes of electroplating wastewater containing nickel ions were studied with ceramic membranes of average pore diameter 0.8 ?m and 0.5 ?m at p H9. The effects of operating time, trans-membrane pressure, cross-flow velocity,temperature and volume concentration factor on permeate flux and nickel rejection were investigated, respectively. Then, the cleaning of fouled membranes were studied. Further,the mathematical model of the microfiltration process was also studied. The results show that, with increasing operating time, permeate fluxes decrease rapidly to a steady value.Steady-state fluxes enhance with increasing trans-membrane pressure or cross-flow velocity, and then do not change any more. Steady-state fluxes enhance with increasing temperature. Optimum operating parameters for the 0.8 ? m membrane are trans-membrane pressure 0.12 MPa, cross-flow velocity 3.0 m/s and temperature 30℃.Optimum operating parameters for the 0.5 ? m membrane are trans-membrane pressure0.14 MPa, cross-flow velocity 3.4 m/s and temperature 30℃.In the process of concentration, permeate fluxes decrease to a steady value and then decreases rapidly, and the nickel rejections are about 99%. The backflushing can increase efficiently permeate flux, it is possible to recover over 94% of the original flux by a program of backflushing;Permeate flux could be recovered effectively to new membrane flux of about 97% by using 0.15wt% hydrochloric acid. In addition, the modified completely blocked model can describe the microfiltration processes.Microfiltration process of electroplating wastewater containing nickel ions for industrial application was also investigated. It found that membrane pore size of 0.8 ? m and the membrane total area of 1.92 m2 can satisfy with the output of 500 ton electroplating wastewater containing nickel ions per year; The flow diagram of serial and four parallel connection was designed, and it can make much profit.