Process Safety and Environmental Protection, Vol.94, 203-211, 2015
Study of flotation conditions for cadmium(II) removal from aqueous solutions
Flotation conditions for cadmium(II) removal from aqueous solutions were investigated. Precipitate flotation techniques "of the first kind" (PFFK) and "of the second kind" (PFSK) were tested, using potassium ethyl xanthate (KEtX) as a precipitating agent for cadmium(II). The surfactants sodium dodecyl sulfate (SDS) and hexadetyltrimethylammonium bromide (HDTMA) were used as collectors for PFFK. The effects of KEtX and collector concentrations, induction time, bubbling time, solution pH and some foreign ions on cadmium(II) removal were studied. Under optimum conditions, cadmium(II) could be removed by PFFK by similar to 93% and >99% using SDS and HDTMA, respectively. By PFSK, removal of about 64% for cadmium(II) was obtained. The two developed precipitate flotation methods were also tested for simultaneous removal of cadmium(II), nickel(II) and cobalt(II) from distilled water and tap water. The effectiveness of PFFK suggests its employment for metal-polluted wastewaters. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.