Removal of Mercury from Pharmaceutical Wastewaters Using Electrocoagulation : A Cleaner Technology Option

The performance of electrocoagulation with iron, aluminum and hybrid Al/Fe sacrificial electrodes for the removal of mercury from pharmaceutical wastewaters was investigated. Operational parameters such as pH, current density, contact time and metal ion concentrations were studied to achieve the higher removal efficiency. The results obtained with synthetic mercury samples revealed that the removal of mercury increases with rising in pH from 2 to 10. In addition, the increase of current density in the range of 0.082 to 0.816 mA cm-2 enhanced the removal up to 99% of mercury. Using iron sacrificial electrodes showed higher mercury removal efficiency comparing with aluminum and hybrid Al/Fe electrode. The laboratory results representing electrocoagulation can be applied for the treatment of mercury containing pharmaceutical wastewaters to reduce mercury concentration up to 0.002 ppm (permissible limit) within 10 min. The sludge generation in this process is quite low. Overall, this method is found to be highly efficient, relatively fast and clean compared to conventional techniques for the removal of mercury