Study On The Treatment Of Wastewater Form Electroless Copper And Nickel Piating

The electroplating industry has developed very rapidly in recent decades.With the rapid development of economy,the problem of environmental pollution has also been aggravated.The quality of electroplating wastewater is complex,especially it is difficult to treat heavy metal chemical plating wastewater containing a large number of complexing agents,which increases the difficulty of electroplating wastewater treatment.Therefore,it is urgent to explore and study efficient and economical electroplating wastewater treatment technology.In this paper,chemical plating wastewater from an electroplating enterprise in Shandong Province is studied.The treatment of copper-nickel electroplating wastewater by neutralization precipitation method,coagulation method,sodium sulfide precipitation method,chelating precipitation method and "sodium sulfide precipitation chelation precipitation method" are studied.Through scheme comparison and optimization analysis of reagent cost,the best treatment scheme of copper-nickel wastewater is obtained,which provides a reference for engineering application and process transformation.The chemical plating wastewater containing nickel is treated by the combined process of "sodium sulfide precipitation chelating precipitation method".Most of the nickel ions can be removed by sodium sulfide precipitation,but some complex ions in the wastewater are still left in the wastewater,and the water quality can not reach the standard.At this time,the chelating precipitation method is used for further treatment.Four kinds of heavy metal trapping agents,HMC-M1,Me2 DTC,TMT01 and TMT15,selected in chelating precipitation method,Among them,the best effect on the removal of nickel ions is the HMC-M1 of Suzhou Zhanjiang Environmental Protection Technology Co,Ltd.The optimum conditions of the combined process are as follows: the p H value of wastewater is adjusted to 8.0,1g/L sodium sulfide is added to the wastewater,stirring reaction is 30 mins,adding 1g/L polyaluminium chloride(PAC)and 0.25g/L polyacrylamide(PAM),static filtration is adjusted to 9.0,adding 400mg/L HMC-M1,stirring for 10 mins,adding 400mg/L PAC and 50mg/LPAM.Finally,the concentration of nickel ion decreased from 89.32mg/L to 0.08mg/L,which meet the discharge requirements of electroplating wastewater(total nickel0.5mg/L).The total cost of treating 1m3 nickel-containing wastewater is 19.15 yuan.Compared with coagulation method and chelating precipitation method,sodium sulfide precipitation method has the characteristics of high treatment efficiency and low cost,and the treated wastewater can be recovered and reused for chemical plating wastewater containing Copper.The optimum technological parameters of sodium sulfide precipitation method are as follows: The p H of the wastewater is adjusted to 7.5 and 0.6g/L sodium sulfide is added,stirring for 30 mins,adding 1g/L PAC and 50mg/L PAM,stirring slowly for 1min,static settlement for30 mins,finally,the concentration of copper ion decreased from 82.68mg/L to0.19mg/L,and the removal rate reached 99.70%,which meet the discharge requirements of electroplating wastewater(total copper 0.5mg/L).The total cost of treating 1m3 copper-containing wastewater is only 4.89 yuan.The Copper-nickel mixed chemical plating wastewater is treated by the combined process of "sodium sulfide precipitation chelating precipitation method".The copper-nickel ions in the wastewater are pre-treated by sodium sulfide precipitation and then treated by chelating precipitation.In this process,HMC-M1 retrapping agent is selected to treat copper-nickel mixed wastewater,the optimum conditions of the combined process are as follows: The p H of the wastewater is adjusted to 9.0,and 1.25g/L sodium sulfide is added to the wastewater for not less than 30 min,adjusting the p H to 10.0 after filtration,adding 400mg/L of HMC-M1,and stirring for 10mins;and then adding 1g/L PAC and 50mg/L PAM.Finally,the concentration of copper ion decreased from 160.40mg/L to 0.15mg/L,and the concentration of nickel ion decreased from 130.60mg/L to 0.09mg/L.The removal rates of copper and nickel are 99.9% and 99.9%,respectively,which meet the discharge requirements of electroplating wastewater(total copper 0.5mg/L,total nickel 0.5mg/L).The total cost of treating 1m3 copper-nickel mixed wastewater is23.09 yuan.