ABSTRACT
This chapter examines the effectiveness of homogeneous oxidation catalysis of metal organic complexes, notably the carboxylate salts of nickel and copper, to facilitate metal recovery from industrial waste effluents. Metal finishing industry electroplating solutions contain various organic complexes such as nickel with citric acid and copper with ethylene diamine tetraacetic acid (EDTA). The principal wastewater treatment routes used for electroless plating solutions consist of chemical or electrolytic reduction to metallic state, precipitation as insoluble compounds (carbonates, hydroxides or sulfides) or removal by adsorption/ion-exchange processes. The chapter presents a study that has been use to mild aeration oxidation of the organometallic complexes, possible in the presence of an oxidation agent like H2O2 which would not add any additional solids to the treated aqueous effluents. A treatment regime consisting of aeration oxidation followed by oxalate precipitation provides a promising alternative for efficient recovery of metals such as cobalt, copper or nickel from electroless plating wastes as potentially marketable by-products.
