Use of sodium trithiocarbonate for remove of chelated copper ions from industrial wastewater originating from the electroless copper plating process

摘要

The possibility of chelated copper ions removal from wastewater from the production of printed circuit boards using Na2CS3 as a precipitant agent has been presented. The use of Na2CS3 (pH 9-9.5, FeC1(3) 1 mL/L, E= +82 mV) enabled successful precipitation of the complexed Cu(II) ions from wastewater (Cu 0.85 mg/L) containing potassium and sodium tartrate (KNaC4H4O6) as a complexing agent. The use of higher doses of Na2XS3 reduced the copper content to 0.05 mg/L (pH 9-9.5, FeCl3 1 mL/L, E= -156 mV). Application of Response Surface Methodology (RSM) allowed for the analysis and evaluation of the impact of the various independent parameters (pH, Fe(III) coagulant dose and 44.26% Na2CS3 dose) on the concentration of Cu(II) in treated wastewater. The lowest values of copper concentration (0.05, 0.02 and 0.03 mg/L) in the treated wastewater was obtained in the three experiments when an alkaline medium (pH 9.5 and 10) and higher concentration of Na2CS3 (0.23 and 0.28 mL/L) were used. The use of Na2CS3 solution under optimal process conditions (pH 9-9.5, E +5 mV, FeCL 0.5-1 mL/L, Na2CS3 0.28 mL/L), allows for almost complete precipitation of complexed copper ions(II) (Cu = 0.05 mg/L), most probably in the form of a brown solid Na2CS3.