The Research Of Nickel Electroplating Wastewater Treated By Chemical Precipitation-Ion Exchange

In this paper,chemical precipitation combined with ion exchange method to treat nickel electroplating wastewater was selected.The influencing factors and reaction mechanism of the method were studied respectively.process parameters of each part are optimized.Finally,the combined process was tested in real wastewater to explore the treatment effect,.The experiment reached the following conclusions:?1?Sodium sulfide is used as a precipitant to treat nickel electroplating wastewater,experiment results showed that Na₂S favors acidic conditions and can be directed utilization;There is no need to adjust the pH greatly during the process,so the running cost is low and the sludge generated is low.The effluent Ni???removal rate can reach 95%.?2?The static adsorption experiments on 732,D751,and CH-90Na resins has been studied by the effects of resin dosage,pH,temperature,and impurity ions on the adsorption performance.It found that D751 resin has large exchange capacity,high selectivity,high regeneration rate,a wide range of pH and temperature,which make a high removal for nickel in wastewater.The intrinsic mechanism of three ion exchange was explored,it revealed that D751 resin is mainly composed of C,O,Na and other elements,which has a porous,rough surface,and contains iminodiacetic acid groups.Infrared spectrum showed that part of Na is replaced by Ni after adsorption,and nickel is chelated on D751 resin.?3?A dynamic small-scale experiment and resin regeneration experiment of chemical precipitation-ion exchange method was performed on actual nickel electroplating wastewater.The results showed that removal rate reached 89%by Na₂S.It was found that after D751 resin was regenerated four times,the adsorption capacity decreased not much,and the regeneration rate reached more than 90%.