Single stage extraction and recovery of hexavalent chromium using blended TOA-TOMAC in palm oil-based diluent via supported liquid membrane process

Abstract

Diluent is an important components in the supported liquid membrane (SLM) process. The conventional diluents used in SLM are usually flammable, volatile, and toxic. To promote a sustainable development, the palm oil was incorporated in the SLM for the removal and recovery of chromium. SLM is a three-phase system with an organic phase containing the carrier in diluent which immobilized in a membrane support and is set in between the simulated chromium and sodium hydroxide solutions that act as a feed and stripping phases respectively. Both solutions were pumped into the membrane support cell in a recycled operation for about 5 hours. To monitor the changes of the chromium ion concentration for both phases, the chromium ion concentration in the feed and stripping phases as a function of time was analysed using an atomic absorption spectrometry (AAS). Several parameters namely type of stripping agent, diluent composition and carrier concentration were investigated. Results showed that about 75 and 73% of chromium was extracted and recovered, respectively at the best conditions of using sodium hydroxide, mixture of palm oil-kerosene (50:50) and TOA-TOMAC (0.20-0.20M). Thus, palm oil is regarded as feasible as a greener diluent in SLM process for chromium ion extraction.