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Experimental investigation of chemical oxygen demand and turbidity removal from cardboard paper mill effluents using combined electrocoagulation and adsorption processes



The removal of chemical oxygen demand (COD) and turbidity from cardboard paper mill effluents was experimentally investigated using aluminum and iron electrodes followed by adsorption of treated wastewater on granular activated carbon (GAC). The effects of electrolyse time, current density, initial pH, adsorption time, stirring, and granular activated carbon (GAC) amount were studied. For electrolyses, the maximum removal efficiencies of COD and turbidity under optimal operating conditions i.e. pH = 5.29 for Al electrode and pH = 7.21 for Fe electrode, with a current density of 4.41 mA/cm2 and operating time of 10 min were 75.37% and 99.93% for Al electrode and 78.76% and 99.92% for Fe electrode, respectively. For electrocoagulation (EC) and adsorption process under operating conditions i.e. pH = 3.21 at 300 rpm with contact time of 120 min for Al electrode and 180 min for Fe electrode, the maximum removal efficiencies of COD were 98.97% and 93.37%, respectively. The results obtained show good adsorption efficiency and short contact time obtained after Al-EC due to interference from color of dissolved iron. The present study proves the effectiveness of electrocoagulation/adsorption process for the highly concentrated organic pollutants present in paper mill effluents. © 2011 American Institute of Chemical Engineers Environ Prog, 2011.

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