Removal of nickel from aqueous solution using cathodic deposition of nickel hydroxide at a modified electrode

Background In the present study, an electrochemical technique was used to remove nickel from aqueous solutions on a laboratory scale using a self‐made Plexiglas cell. Electrodes comprising a stainless steel net coated with single‐walled carbon nanotubes ( SWCNTs @ SSN ) were used as both the anode and the cathode. The effects of various parameters on the percentage of nickel removed were investigated, including the solution pH , applied voltage, electrolyte concentration, and the amount of SWCNTs coated on the electrodes . Results The optimal parameters were found to be pH  10.0, applied voltage 2.5 V, and electrolyte concentration 10 g dm ‐3 . Under optimal conditions, 95.1% of the nickel present in nickel‐contaminated factory wastewater was removed. The mechanism of nickel removal was also investigated. X‐ray photoelectron spectroscopy ( XPS ) and scanning electron microscopy ( SEM ) analyses showed that the nickel ions were being removed in the form of Ni( OH ) 2 , which was deposited on the cathode. The SWCNTs @ SSN electrodes were regenerated easily . Conclusion The results of the study proved that the method is a potential technique for the treatment of industrial wastewater containing heavy‐metal ions. © 2013 Society of Chemical Industry