US EPA

5125834 

Journal Article 

Comparative evaluation of alkali precipitation and electrodeposition for copper removal in artisanal gold smelting wastewater in the Philippines 

Vivas, EL; Alfafara, CG; Migo, VP; Cho, Kuk; Detras, MCM; Trinidad, LC; Mendoza, MD; Lee, S 

2019 

Yes 

Desalination and Water Treatment
ISSN: 1944-3994
EISSN: 1944-3986 

150 

396-405 

10.5004/dwt.2019.23790 

WOS:000463027500037 

Alkali precipitation and electrodeposition for copper removal in artisanal gold smelting wastewater were evaluated. Alkali precipitation was done by dosing the wastewater with sodium hydroxide solution. Electrodeposition was conducted at operating current of 4 A for 3 and 6 h. Alkali treatment exhibited 99.83% removal efficiency, albeit residual copper concentration was still above effluent standards. Lead was no longer detected at pH >= 6 while 87.82% of cadmium was removed at maximum precipitation. Generation of metal hydroxide sludge implied the need for a post-treatment. Electrodeposition demonstrated superior copper removal efficiency (99.98%). With appropriate selection of electrolysis time, it could achieve complete copper removal. It had low energy consumption and indicative treatment cost, and no sludge generation. Electrodeposition current efficiency was relatively low due to other wastewater components which could have consumed a fraction of applied current. Kinetics evaluation showed a three-step electrodeposition process, each stage having a different reaction rate order. Lead was not detected after 3 h while 50.00% of cadmium was removed after 6-h electrolysis. Considering removal efficiency without sludge generation, indicative treatment cost, and value recovery of deposited copper, results revealed that electrodeposition has some advantage over alkali precipitation for the remediation of artisanal gold smelting wastewater. 

Artisanal gold smelting; Chemical precipitation; Copper removal; Current efficiency; Electrochemical treatment; Electrodeposition; Heavy metals