Modified Sugarcane leaf biochar for remediation of polycyclic aromatic hydrocarbons (PAHs) from wastewater: Activation, optimization, mechanism

Abstract

Adsorbents from biomass, particularly biochar, have shown great efficacy in treating wastewater because of their easy synthesis and favorable surface properties. Economic considerations are crucial for biochar to be a sustainable biosorbent in the long run. Sugarcane, a globally abundant crop, provides valuable post-harvest waste that can be converted into high-quality biochar. This study explores producing activated biochar from sugarcane leaves using CO₂ to remove polycyclic aromatic hydrocarbons (PAHs) from wastewater. Naphthalene (NAP) and Phenanthrene (PHE) were used as model PAHs for the study. Using response surface methodology, synthesis conditions were optimized, achieving an activated biochar with a surface area of 382.04 m²/g and a yield of 19.57 %. PAHs batch adsorption experiments were conducted, and depending on the process parameters, a removal efficiency of 88 – 90 % was achieved. Cost analysis showed that producing 1 kg of sugarcane leaf-activated biochar costs $1.37, with a removal cost of $0.030 to $0.035 per gram of PAHs. These findings indicate the potential of activated biochar from sugarcane leaves as an effective, cost-efficient adsorbent for PAH remediation in wastewater.