Analysis of the role of various biochar in the remediation of heavy metals in contaminated water and its kinetics study

Biochar prepared from agricultural wastes has gained great attention as a cost-effective treatment for metal-contaminated water. In this study, the effectiveness of corn cob and sugarcane bagasse-derived biochar for metals (Pb, Ni, and Cu) removal from an aqueous medium was exam-ined following their physical, chemical, and structural characterization. Batch sorption experiments were carried out by employing the Langmuir and Freundlich equations. The results indicated that separation factor (RL) values lay in the range of 0 and 1 representing the productive adsorption. The optimum dosage for metal adsorption can be recommended as 30 g L-1. The optimum adsorption conditions were found at 6.5 and 5.5 pH, 1.5 g adsorbent dose, and at 180 min equilibrium time, for both corn cob and sugarcane bagasse biochars. At pH 6.5, adsorption capacities of Pb, Ni, and Cu were found maximum i.e., 11.34, 15.71, and 11.96 mg kg(-1) for corn cob and 8.96, 15.46, and 12 mg kg(-1), for sugarcane bagasse biochars, respectively. The metal adsorption kinetics was ana-lyzed via four different types of the pseudo-second-order kinetic model. Moreover, the corn cob biochar showed a more pronounced activity in the removal of metals compared to sugarcane bagasse biochar. Hence, it was concluded that corncob and sugarcane bagasse-derived biochars could be utilized as economical bio-adsorbents for the heavy metals removal from wastewater. (C) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.

Automated summary

This study examined the efficiency of corn cob and sugarcane bagasse-derived biochar for removing metals (Pb, Ni, and Cu) from water. The optimal adsorption conditions were determined, and it was found that corn cob biochar had better metal removal activity compared to sugarcane bagasse biochar. The results suggest that these biochars can be used as cost-effective bio-adsorbents for heavy metal removal from wastewater.