Abstract: (13247 Views)
Background and purpose: Cyanide is a species of high toxicity that is found mostly in industrial
effluents such as electroplating, metal mining, metallurgy and metal cleaning processes. Entrance of it to
existing environment contains a hazardous to health. The purpose of this study was to compare efficiency
of both sonochemical and sonochemical / hydrogen peroxide processes for cyanide removal from aqueous
solutions.
Materials and methods: This study has been used from a productive set of 500w power
ultrasound waves in of two frequencies 35 kHz and 130 kHz. Experiments were performed with different
initial ratio 1/1, 1/3 and 1/5 and at initial cyanide concentrations varying from 2.5 to 75 mg/L.
in this study, Effects of parameters such as pH time, initial cyanide concentration, hydrogen peroxide/
cyanide and frequency on removal efficiency of mention processes have been studied.
Results: The results of the study showed that the maximum removal efficiency of cyanide had
been achieved to 74% by sonochemical process at frequency of 130 kHz, at time of 90 min, at pH of 11,
at initial cyanide concentration of 2.5 mg/l and with initial ratio of 1/5. However in similar
condition, removal efficiency of cyanide had been achieved to 85% by sonochemical/ hydrogen peroxide
process.
Conclusion: The results of the study showed that rates of cyanide degradation under different
conditions had always been quite low, and also the rate of cyanide degradation was first high but it was
later substantially reduced. Results of the study showed that efficiency of sonochemical/hydrogen
peroxide process is more than of sonochemical process for cyanide removal from aqueous solutions. Also
removal efficiency of cyanide has direct relationship with pH, frequency, hydrogen peroxide and time
however, it has reverse relationship with cyanide concentration for process.