SOLVENT EXTRACTION OF METALS FROM LIQUID PHOTOGRAPHIC WASTE USING ACIDIC EXTRACTANTS

Abstract. Currently, the exhaustion of hazardous wastes from industrial becomes a more serious problem all over the world. If we focus to photographic waste, the valuable metals and its toxicity become a factor of consideration in economic and environmental aspects for recovery and separation. Solvent extraction technology is a technique which has a great potential for metal recovery. Therefore, different types of acidic extractants (Cyanex 272, Cyanex 302, and D2EHPA) were examined in terms of their capability and selectivity in extracting metals from photographic wastes. It was found that an extractant containing a P=S functional groups (Cyanex 302) strongly extracts almost 97 % silver at pH equilibrium ranging from 6 to 9. It is also found that Cyanex 302 was very selective towards silver than other metals that existed in the real photographic waste. The Cyanex 272 and D2EHPA also provide a good metal extraction performance at pH 7 and 8.3 respectively but they are only selective to iron at pH 9. Furthermore, the extraction capacity increases with increasing in extractant concentration until it achieves plateau due to excess of free extractant