title: Removal of copper from water by electrocoagulation process--effect of alternating current (AC) and direct current (DC).
abstract: PURPOSE AND AIM: In general, direct current (DC) is used in an electrocoagulation processes. In this case, an impermeable oxide layer may form on the cathode as well as corrosion formation on the anode due to oxidation. This prevents the effective current transfer between the anode and cathode, so the efficiency of electrocoagulation processes declines. These disadvantages of DC have been diminished by adopting alternating current (AC) in electrocoagulation processes. The main objective of this study is to investigate the effects of AC and DC on the removal of copper from water using magnesium alloy as anode and cathode.
  
  
  METHODS
  Magnesium alloy of size 2.0 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. Copper adsorbed magnesium hydroxide coagulant was characterized by SEM, EDAX, XRD, and FTIR.
  
  
  RESULTS
  The results showed that the optimum removal efficiency of copper is 97.8 and 97.2 % with an energy consumption of 0.634 and 0.996 kWh/m(3) at a current density of 0.025 A/dm(2), pH of 7.0 for AC and DC, respectively. The adsorption of copper is preferably fitting the Langmuir adsorption isotherm for both AC and DC respectively. The adsorption process follows the second-order kinetics model with good correlation. Temperature studies showed that adsorption was endothermic and spontaneous in nature.
  
  
  CONCLUSIONS
  The magnesium hydroxide generated in the cell removes the copper present in the water, reducing the copper concentration to less than 1 mg/L, making it safe for drinking. The results of the scale-up study show that the process was technologically feasible.
authors.affiliation: CSIR-Central Electrochemical Research Institute, Karaikudi 630 006, India.
authors.forename: Ramakrishnan
authors.initials: R
authors.lastname: Kamaraj
authors.forename: Pandian
authors.initials: P
authors.lastname: Ganesan
authors.forename: Jothinathan
authors.initials: J
authors.lastname: Lakshmi
authors.forename: Subramanyan
authors.initials: S
authors.lastname: Vasudevan
mesh_terms: D003300:Copper / Q000032:analysis / Q000737:chemistry*; D004560:Electricity; D004563:Electrochemistry; D007700:Kinetics; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D003300:Copper