Adsorption and Extraction of Gold by Using Polymer Inclusion Membrane: Effect of Membrane Materials on Performance

Precious metals, such as gold, are widely used in the manufacturing of various products, including electronic components and jewelry, due to their unique physical and chemical properties. Recycling these metals is economically advantageous, as the concentration of valuable metals in discarded waste is often higher than in natural resources. In this study, polymer inclusion membranes (PIMs) with various compositions were fabricated and characterized. The optimal pH for each membrane was determined to be 1, based on pH experiments. Temperature and contact time conditions varied for different membrane materials: membranes containing polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), and cellulose triacetate (CTA) exhibited optimal performance at 25°C for 30 minutes, 35°C for 60 minutes, and 45°C for 360 minutes, respectively. Among the tested membranes, the best-performing compositions for each base polymer were identified as CTA-2, PVDF-5, and PVC-4. For gold extraction studies, membranes incorporating PVC, trioctylamine (TOA), and methyltrioctylammonium chloride (Aliquat 336) were developed based on adsorption results. Experimental findings indicated that 0.25M hydrochloric acid (HCl) was the optimal concentration for the process. Extraction analysis determined that the gold concentration in the feed phase should be 10 parts per million (ppm). The most effective membrane for extraction was composed of 40% PVC, 40% A336, and 20% TOA. Under these optimized conditions, the gold recovery factor after 6 hours was recorded as 37.93%.