The destruction and removal of cyanide species from process effluents have been studied by numerous investigators. Present cyanide treatment technologies include oxidation, biological and natural degradation, membrane separation and precipitation. The applicability of the above process is dependent upon the process stream, the amount and type of cyanide species and the minimum discharge standard imposed by the state and federal agencies.; The objective of this investigation is to develop a cyanide removal process which can be used over a wide range of process streams and at the same time meet the required cyanide discharge limits in a cost effective manner. In this research, a thiosulfate process in the presence of copper sulfate has been utilized to remove cyanide from synthetic solution, process waters and different industrial sludges. Addition of sodium and ammonium thiosulfate in the presence of copper can reduce the cyanide level in the treated solution to as low as 0.005 mg/l. The thiosulfate process is dependent upon the order of addition, mixing time and system pH.; A factorially designed, statistical experimental approach was used to establish the optimum conditions for cyanide removal efficiency from a typical cyanide pond water. In addition the precipitated product obtained after cyanide removal was characterized by the Fourier Transform Infrared spectroscopy (FTIR). FTIR analysis has shown the absence of cyanide species in the precipitated product. It is believed that a stable complex copper–sulfur-cyano species formed during the removal process. The resultant species is stable over a wide pH range.
展开▼
