A simple and cost effective method for recovering gold from the jewelers’ electroplating waste water workshops using nano-wires structure of manganese oxide as an adsorbent

Abstract

In this work a nanostructure manganese oxide-based adsorbent were utilized to recover gold from the jeweler’s electroplating waste water workshops. The method is low-cost and is capable of extracting gold in the form of metal nano-to-micrometer-size particles down to sub-ppm-level from the aqueous jeweler’s waste with a high yield. This method introduces good selectivity and recyclability and with a minimal environmental impact. In this study, adsorption parameters such as number of treatments, holding time, pH and the agitation speed of mixing in the gold adsorption process were examined. The results revealed that for the optimum operating condition; more than 77.2% of gold was adsorbed onto the manganese oxide after only 2 hours. The manganese oxide adsorbent were prepared by a low-temperature synthesis followed by acid treatments which exhibits a wire-like morphology of agglomerated nanometer-size crystallite grains covered with active protonated sites. The method is well suited to gold recovery from a very dilute solution. The protonation–suspension–filteration–washing process adopted in this work could be recycled without a noticeable degradation in the yield.