Waste utilization: The removal of textile dye (Bomaplex Red CR-L) from aqueous solution on sludge waste from electrocoagulation as adsorbent

The potential of removing Bomaplex Red CR-L dye from electro coagulation sludge has been investigated for different Bomaplex Red CR-L concentrations with varying adsorbent amount, temperature, pH and stirrer speed. Removal of Bomaplex Red CR-L is found to be high at lower pH values. The maximum adsorption of the dye has been achieved in aqueous solutions using 0.5 g of calcinated sludge from electro coagulation at a pH of 2.0 within 20 min. The Langmuir and Freundlich isotherm models were tested and it was found that the Langmuir equation was fitted better than the Freundlich equation. Maximum adsorption capacity (qm) was calculated as 192.31 mg g− 1 at 333 K. In addition, the adsorption data obtained at various temperatures were successfully applied to pseudo first-order, pseudo second-order and intraparticle diffusion models. The rates of adsorption were found to conform to pseudo second-order kinetics with good correlation (R2 ≥ 0.9997). This study showed that calcinated the sludge from electrocoagulation has a highly adsorbent capacity.

Research Highlights
► Calcined sludge from electrocoagulation was utilized as an adsorbent.
► It was used for the removal of Bomaplex Red CR-L from aqueous solutions.
► The adsorption of Bomaplex Red CR-L on calcined sludge from electrocoagulation is endothermic.
► The adsorption equilibrium was well described by the Langmuir isotherm model.
► Adsorption kinetics of Bomaplex Red CR-L in a batch system was found to conform to pseudo-second order model.