Removal of chromium from tannery industry wastewater using iron-based electrocoagulation process: experimental; kinetics; isotherm and economical studies

Heba A El-Gawad; Gamal K Hassan; Karim M Aboelghait; Walaa H Mahmoud; R M Mohamed; Ahmed A Afify

doi:10.1038/s41598-023-46848-9

Removal of chromium from tannery industry wastewater using iron-based electrocoagulation process: experimental; kinetics; isotherm and economical studies

Sci Rep. 2023 Nov 10;13(1):19597. doi: 10.1038/s41598-023-46848-9.

Authors

Heba A El-Gawad¹, Gamal K Hassan², Karim M Aboelghait³, Walaa H Mahmoud⁴, R M Mohamed⁵, Ahmed A Afify⁵

Affiliations

¹ Department of Engineering Mathematics and Physics, Higher Institute of Engineering, El- Shorouk Academy, Cairo, Egypt.
² Water Pollution Research Department, National Research Centre, 33 Behooth St, P.O. Box 12622, Dokki, Giza, Egypt.
³ Water Pollution Research Department, National Research Centre, 33 Behooth St, P.O. Box 12622, Dokki, Giza, Egypt. km.aboelghait@nrc.sci.eg.
⁴ Chemistry Department, Faculty of Science, Cairo University, Giza, 12613, Egypt.
⁵ Chemical Engineering Department, Canal Higher Institute of Engineering and Technology, Suez, Egypt.

Abstract

Chromium is a hazardous compound from industrial processes, known for its toxicity, mutagenicity, teratogenicity, and carcinogenicity. Chemical methods are efficient but cost-effective alternatives with reduced sludge are sought. Electro-coagulation, utilizing low-cost iron plate electrodes, was explored for factual tannery wastewater treatment in this manuscript. Operating parameters such as initial chromium concentration, voltage, electrode number, operating time, agitation speed and current density has been studied to evaluate the treatment effeciency. Under optimal conditions (15 V, 0.4 mA/cm², 200 rpm, 330 ppm chromium, 8 iron electrodes with a total surface area of 0.1188 m², 3 h), chromium elimination was 98.76%. Iron anode consumption, power use, and operating cost were 0.99 gm/L, 0.0143 kW-h/L, and 160 EGP/kg of chromium eliminated, respectively. Kinetics studies were pursued first-order reaction (97.99% correlation), and Langmuir isotherms exhibited strong conformity (Langmuir R²: 99.99%). A predictive correlation for chromium elimination (R²: 97.97%) was developed via statistical regression. At HARBY TANNERY factory in Egypt, industrial sewage treatment achieved a final chromium disposal rate of 98.8% under optimized conditions.