Effect of alternating and direct current in an electrocoagulation process on the removal of cadmium from water

Central Electrochemical Research Institute, Karaikudi, India.
Water Science & Technology (Impact Factor: 1.21). 01/2012; 65(2):353-60. DOI: 10.2166/wst.2012.859
Source: PubMed

ABSTRACT The main objective of this study was to investigate the effects of AC and DC on the removal of cadmium from water using iron as anode and cathode. The various operating parameters on the removal efficiency of cadmium were investigated. The results showed that the optimum removal efficiency of 98.1 and 97.3% with the energy consumption of 0.734 and 1.413 kWh/kL was achieved at a current density of 0.2 A/dm(2), at pH of 7.0 using AC and DC respectively. The adsorption process follows second order kinetics and the temperature studies showed that adsorption was endothermic and spontaneous in nature.

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    ABSTRACT: The present study provides an optimization of electrocoagulation process for the recovery of hydrogen and removal of nitrate from water. In doing so, the thermodynamic, adsorption isotherm, and kinetic studies were also carried out. Aluminum alloy of size 2 dm(2) was used as anode and as cathode. To optimize the maximum removal efficiency, different parameters like effect of initial concentration, effect of temperature, pH, and effect of current density were studied. The results show that a significant amount of hydrogen can be generated by this process during the removal of nitrate from water. The energy yield calculated from the hydrogen generated is 3.3778 kWh/m(3). The results also showed that the maximum removal efficiency of 95.9 % was achieved at a current density of 0.25 A/dm(2), at a pH of 7.0. The adsorption process followed second-order kinetics model. The adsorption of NO (3) (-) preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules. Thermodynamic studies showed that adsorption was exothermic and spontaneous in nature. The energy yield of generated hydrogen was ~54 % of the electrical energy demand of the electrocoagulation process. With the reduction of the net energy demand, electrocoagulation may become a useful technology to treat water associated with power production. The aluminum hydroxide generated in the cell removes the nitrate present in the water and reduced it to a permissible level making the water drinkable.
    Environmental Science and Pollution Research 06/2012; 20(4). DOI:10.1007/s11356-012-1028-4 · 2.76 Impact Factor
  • Desalination and water treatment 08/2014; DOI:10.1080/19443994.2014.951692 · 0.99 Impact Factor
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    ABSTRACT: In this study, removal of cadmium (Cd), copper (Cu) and nickel (Ni) from a simulated wastewater by electrocoagulation (EC) method using batch cylindrical iron reactor was investigated. The influences of various operational parameters such as initial pH (3, 5, 7), current density (30, 40, 50 mA/cm 2) and initial heavy metal concentration (10, 20, 30 ppm) on removal efficiency were investigated. It was seen from the results that removal efficiencies were significantly affected by the applied current density and pH. The experimental results indicated that after90 minutes electrocoagulation the highest Cd, Ni, Cu removal of 99.78%, 99.98%, 98.90% were achieved at the current density of 30 mA/cm 2 and pH of 7 using supporting electrolyte (0,05 M Na 2 SO 4) respectively. The experimental results revealed that the removal of heavy metal ions by our design electrochemical cell can be successfully achieved.


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May 20, 2014