Copper recovery from low concentration waste solution using Dowex G-26 resin

Huge amounts of effluent of low copper content are generated in electrical and electronic parts manufacturing industries. Here we report an adsorption process using strongly acidic exchanger Dowex G-26 for copper recovery from dilute sulfate solution containing 0.5–0.7 g/L copper, which is similar to the chemical and mechanical polishing (CMP) waste generated in electronic industries. The structures of activated and copper-loaded resins were compared by FT-IR spectroscopic characterization to confirm the adsorption phenomena. Various process parameters viz. contact time, solution pH, resin dose were investigated for copper recovery from the waste effluent. Copper adsorption from the solution was complete within a contact time of 14 min for an aqueous/resin (A/R) ratio of 100 mL/g and equilibrium pH of 2.5. The mechanism for copper adsorption by Dowex G-26 resin was found to follow a Langmuir isotherm and second-order reaction rate. 99.7% of the copper was eluted effectively from the loaded resin by 10% sulfuric acid at an A/R ratio of 25 in a contact time of 20 min to produce a copper-enriched solution. After copper recovery, the raffinate generated could be disposed safely without affecting the environment.