Electrocoagulation: Removing colour and COD from simulated and actual batik wastewater

• Published in: DESALINATION AND WATER TREATMENT
• Main Authors: Fadzli, Julia; Puasa, Siti Wahidah; Him, Nik Raikhan Nik; Hamid, Ku Halim Ku; Amri, Nurulhuda
• Format: Article
• Language: English
• Published: DESALINATION PUBL 2024
• Subjects: Engineering; Water Resources
• Online Access: https://www-webofscience-com.uitm.idm.oclc.org/wos/woscc/full-record/WOS:001288578400001
• ISSN: 1944-3994; 1944-3986
• DOI: 10.1016/j.dwt.2024.100658

The study examined the properties of reactive black 5 (RB5) and reactive orange 16 (RO16) and how their molecular structures affected colour and COD removal in simulated batik wastewater. It also evaluated the impact of Al rod-type electrodes on energy and electrode consumption during electrocoagulation (EC). Parameters including current densities (10-30 mA/cm2), initial pH (3-11), reaction time (10-40 min), and NaCl dosage (0.5-2.0 g/L) were evaluated for maximum colour and COD removal. The study found that the highest colour removal rates for RB5, RO16, and their mixtures were 98.60 %, 58.40 %, and 70.69 %, respectively, while COD removal rates were 95.06 %, 91.83 %, and 96.69 %. FTIR analysis characterised the dyes, and a cost analysis showed energy and electrode consumption at 5.26 kWh/m3 and 0.234 kg/m3, resulting in an operating cost of RM 1.6/kWh. The best conditions for maximal removal were determined to be pH 3, an IED of 1 cm, 1.5 g/L NaCl, 120 rpm, 30 mA/cm2, and a reaction time of 40 min, as validated by regression analysis. The EC process applied to actual batik wastewater proved effective, achieving 96.69 % colour removal and 97.93 % COD removal. The challenges and potential avenues for future research within the EC process were also addressed.