Studies Relating to Removal of Arsenate by Electrochemical Coagulation: Optimization, Kinetics, Coagulant Characterization

Abstract

The present investigation aims to remove arsenate [As(V)] by electrochemical coagulation using mild steel as anode and cathode. The results showed that the optimum removal efficiency of 98.6% was achieved at a current density of 0.2 A dm À2 , at a pH of 7.0. The effect of current density, solution pH, temperature, co-existing ions, adsorption isotherm, and kinetics has been studied. Kinetics reveals that the removal of arsenate by electrochemical coagulation is very rapid in the first 15 min and remains almost constant with the progress of reaction. The adsorption kinetics obeys the second-order rate expression. An equilibrium isotherm was measured experimentally and the results were analyzed by Langmuir, Freundlich, Dubinin-Redushkevich, and Frumkin using the linearized correlation co-efficient. The characteristics parameters for each isotherm were determined. The Langmuir adsorption isotherm was found to fit the equilibrium data for arsenate adsorption. Temperature studies showed that the adsorption was endothermic and spontaneous in nature.

Effects of alternating and direct current in electrocoagulation process on the removal of fluoride from water

“…The amount of fluoride removed depends upon the quantity of aluminum hydroxide adsorbent generated, which is related to the time and current density. The amount of adsorbent [Al(OH) 3 ] was determined from the Faraday law:20 where I is current (A), t is the time (s), M is the molecular weight, Z is the number of electrons involved, and F is the Faraday constant (96 485.3 coulomb mole −1 ). To investigate the effect of current density on fluoride removal, a series of experiments was carried out on solutions containing a constant pollutant loading of 5 mg L −1 , at pH 7.0, with the current density varied from 0.25 to 1.5 A dm −2 using both AC and DC current sources (Table 1).…”

Preparation and characterization of higher degree‐deacetylated chitosan‐coated magnetic adsorbent for the removal of chromium(VI) from its aqueous mixture

“…The q m and K L values can be calculated from the linear form of eq. by plotting between 1/ q e and 1/ C e …”

Electrocoagulation in Wastewater Treatment

“…Kinetics determined that the removal was within 15 minutes, following a second order rate absorption. Finally, Langmuir adsorption isotherm describes appropriately this condition [13].…”