Effect of multi-walled carbon nanotubes (MWCNT) addition on chemical oxygen demand (COD) removal by electrocoagulation from landfill leachate

The effect of nanomaterial addition on COD removal from leachate by electrocoagulation was investigated. In this study, COD removal in leachate was realized in a batch reactor according to the changes in adsorbent dosage and retention time. The effect of multi-walled carbon nanotube addition on the treatment efficiency of COD removal under optimum conditions (0.8 A current, Fe-Fe electrode, pH=6, 250 rpm mixing speed and 40 min contact time) was investigated. The highest COD removal of 32.89% was obtained with 1 mg MWCNT at 0.8 A current, Fe-Fe electrode, pH=6, 250 rpm mixing speed and 40 min contact time with a volume of 800 ml. According to the high coefficient of determination, the most appropriate isothermal models are Temkin, Flory-Huggins, Jovanovic, Dubinin-Radushkevich, Flory Huggins, Fowler Guggenheim, Jovanovic, Harkin-Jure, and Haisey. Statistical analysis showed that CNT addition had a significant effect on COD removal and that pH and temperature had the greatest effect on this effect. As a result, it was suggested that the added nanomaterial should be functionalised for high treatment efficiency in COD removal.