Treatment of Cr, Ni and Zn from galvanic rinsing wastewater by electrocoagulation process using iron electrodes

Abstract

A B S T R A C TGalvanizing plants contain reasonable amounts of heavy metal ions which pose a serious risk to humans, animals and the environment. In the present study, removal efficiencies of Cr, Ni and Zn from galvanic rinse wastewater (GRW) by electrocoagulation (EC) process using iron plate electrodes were investigated in a laboratory scale EC reactor. The effects of operational variables, such as operating time (0-50 min), current density (10-40 A/m 2 ), initial pH i (2.4-6.4) and electrode connection modes (MP-P: monopolar-parallel, MP-S: monopolarserial and BP-S: bipolar-serial), on the removal efficiencies of heavy metals were explored to determine the optimum operating conditions. Removal efficiencies of 99.77% for Cr, 85.62% for Ni and 99.04% for Zn at the optimum operating conditions (pH i 5.4, current density of 30 A/m 2 , operating time of 30 min and MP-P electrode connection mode) were obtained. The results showed that Cr, Ni and Zn removal efficiencies from GRW increased with increasing current density and pH at MP-P electrode connection mode. The results showed that EC can effectively reduce metal ions to a very low level. Amount of sludge generated and operating cost at the optimum conditions during the EC process were calculated as 2.32 kg/m 3 and 0.70 €/m 3 . This study revealed that the EC process was very effective for removal of Cr, Ni and Zn from GRW.

Evaluations of operating parameters on treatment of can manufacturing wastewater by electrocoagulation

“…However, there were some studies in literature about removals of heavy metals such as Ni, Cr, Cd, Zn, Cu, etc except for Zr and Al by the EC [65]. The comparisons and evaluations of removal efficiencies and operating costs from some studies were reported [66].…”

Pollutant removal from mining processing wastewater by electrochemical method

“…The efficiency of pollutant removal increases with increasing reaction time until it reaches the maximum value in the optimum reaction time. Many authors have found that the optimum time values in the literature for removal of heavy metals are between 10 and 60 minutes (Gomes et al, 2007;Song et al, 2016;Akbal and Camci, 2010;Hamdan and El-Naas, 2014;Kobya et al, 2015). Time optimization, it was determined that the optimal contact time was 20 minutes for the FE electrode and 30 minutes for the Cu electrode.…”

Removal of heavy metals by electrocoagulation from hydrogenocarbonate-containing waters: Compared cases of divalent iron and zinc cations

“…Removal of cations of metals e.g. Pb, Cd, Ni, Cu, Zn contained in various waters by EC has been investigated for the sake of a better understanding of the phenomena involved (Adhoum et al 2004;Heidmann and Calmano 2008;Kobya et al 2015;Al-Shannag et al 2015;Lu et al 2015), in addition to production of purified water. From the above investigations, removal of heavy metal cations Me 2+ is allowed by occurrence of (i) specific adsorption of the pollutants by complexation with soluble species, or by surface complexation on the Al /Fe hydroxides flocs; (ii) adsorption through electrical neutralization and electrostatic attraction between the pollutants and the charged flocs; (iii) formation of Me(OH)2 near the cathode surface upon water reduction to hydrogen and hydroxide ions, followed by co-precipitation of the two hydroxides.…”