Removal of chromium (III) from tannery wastewater by electrochemical peroxidation process in a bench scale reactor

Abstract

Chromium(III) used in tanning process is not consumed fully and around 30-40% of Chromium(III) is washed away to the environment causing severe environmental problem especially to the aquatic system. To remove Chromium(III) from wastewater, many different treatment techniques have been developed. This study deals with the ability of electrochemical peroxidation process for the removal of Chromium(III) from tannery wastewater in a batch stirred tank bench scale reactor with hopper bottom of 5 L working volume equipped with two iron electrodes which were investigated. The removal percentage of chromium was determined by varying operating parameters such as pH = 2-8, Fe 2+ = 2-5 mg/L, H 2 O 2 = 5-20 mg/L and current density = 10-40 mA/cm 2 were studied. The results showed that the Chromium(III) removal efficiency of 87% was achieved under optimum condition such as pH = 2, Fe 2+ = 2 mg/L H 2 O 2 = 15 mg/L, current density = 30 mA/cm 2 and contact time was 120 min with an electrical energy consumption of 0.073 kWh/L. The operating costs for the removal of Chromium(III) was found to be 0.4 $/m 3 for treated tannery wastewater. The electrochemical peroxidation process proved to be an efficient and appropriate technique for the removal of Chromium(III) from tannery wastewater.

Solar photo-assisted electrochemical peroxidation process for the sustainable treatment of tannery industry wastewater

“…The results are shown in Figure 8. Compared to synthetic wastewater, real wastewater requires a higher concentration of Fe 2þ to start the Fenton reaction, which will damage large molecules (Selvabharathi et al 2019). If the concentration is kept low, adding ferrous salts to achieve metal coagulation may be enough to entirely remove the organic contaminants.…”

Decolorization of industrial wastewater using electrochemical peroxidation process

“…The electrochemical peroxidation process has a similar mechanism to electrocoagulation, but better COD removal results were obtained with the addition of H2O2 [12][13][14]. Several studies have reported that COD of coke wastewater can be removed up to 90 % by electrochemical peroxidation, whereas by electrocoagulation, up to 30 % was removed only [13].…”

A bench-scale electrochemical peroxidation reactor performance on removal of organic pollutants from tannery industrial wastewater

“…There is inhibition of biological degradation due to chromium content and sulphide ions indicating the antibacterial activity. Conventional methods used for wastewater treatment are expensive and are not eco-friendly besides requiring high energy and large quantities of chemicals [6]. The increasing demand for eco-friendly technologies has forced researchers, scientists and leather industries to search for cost-effective alternatives.…”

“…As seen in Eqs. ( 4) and (5), this is not quite feasible in the oxidation phase that leads to quantification of H 2 O 2 and Fe 2+ [6]. According to Eq.…”

“…( 1), the formed OH • radicals oxidise the organic compounds (RH) and convert them to H 2 O and CO 2 as given in Eq. (6).…”