Thermodynamic Study for Arsenic Removal from Freshwater by Using Electrocoagulation Process

Abstract

Insert Industrial treatment of mineral-processing and non-ferrous metal-smelting acid wastewater effluents is becoming an enormous worldwide problem. In Mexico, heavy metalscontaminated natural waters, including freshwater, surface water and ground water, are a significant problem as some of these compounds are known as toxic, mutagenic, and carcinogenic. A very promising electrochemical treatment technique that does not require chemical additions to remove arsenic is electrocoagulation (EC) with air injection. The proposed electrochemical process is efficient because used low cost iron electrodes and promising in industrial application. Theoretical the purpose of this research was to investigate the thermodynamic of arsenic adsorption on iron species using the Langmuir's Isotherm. Also, thermodynamic parameters such as ∆H  , ∆S  and ∆G  were calculated and the adsorption process was found to be exothermic and spontaneous. X-ray Diffraction and Scanning Electron Microscopy, were used to characterize the solid products formed during EC. The results of this study suggest that magnetite particles and amorphous iron oxyhydroxides are present in the examined EC products and this study indicate that arsenic can be successfully adsorbed on iron species by electrocoagulation process. Field pilot-scale study demonstrated the removal of As(III)/As(V) with an efficiency of more than 99% from both wastewater and wells.

Electrocoagulation Process for Recovery of Precious Metals from Cyanide Leachates Using a Low Voltage

“…Several authors have used the electrocoagulation (EC) to remove heavy metals. − The EC has also been investigated as an alternative process for the recovery of precious metals, mainly for general gold and silver processes. − Gold and silver are generally recovered by electrowinning (EW) from cyanide solutions purified and concentrated by carbon adsorption. In addition, electrocoagulation is used for the treatment of high-grade gold solutions.…”