Cloud Point Extraction of Trivalent Chromium from Aqueous Solutions Using Different Nonionic Surfactants

Cloud point extraction (CPE) of trace metals from aqueous solutions is based on clouding phenomena of non-ionic surfactant used. This work aimed to separate Cr (III) ions from water samples using a cost-effective and environment-friendly method as CPE at high efficiency. Four different types of non-ionic surfactants have been selected and investigated for CPE to achieve high performance. Polyethylene glycol, glycerine, PO/EO block polymer, and ethoxylated polyamine surfactants are used in CPE experiments. The influence of important factors has been studied and optimized on the percent of extraction yield, pH, surfactant amount, Cr (III) ions concentration, temperature, and centrifugation time as well as ammonium pyrrolidine dithiocarbamate (APDC) as chelating agent to enhance the separation process. As a result, polyethylene glycol, PO/EO block polymer, and ethoxylated polyamine were excellent surfactants since a complete separation of Cr (III) at pH 8 and a lower equilibrium time of about 2 minutes has been achieved.