Screening of sugarcane bagasse-derived biochar for phenol adsorption: optimization study using response surface methodology

The utilization of biochar, prepared from the agricultural biomass, is one of the economic approaches. To assess the ability of biochar as an adsorbent, sugarcane bagasse-derived biochar was utilized for the removal of phenol from aqueous solution. Phenol, an industrial discharge and a ubiquitous organic pollutant, was chosen as the model compound to determine the adsorption capacity of sugarcane bagasse-derived biochar. The sugarcane bagasse was pyrolyzed at 400, 600, and 800 °C under an N2 atmosphere. Among all the three raw biochars, the biochar obtained at 600 °C showed maximum removal efficiency, 74.2%. Based on higher efficiency, SB-600 biochar was further chemically treated with nitric acid (HNO3) and sodium hydroxide (NaOH) to enhance its adsorption capacity. Sugarcane bagasse-derived magnetic biochar was also fabricated using the pre-pyrolysis modification. Maximum removal (96.1%) efficiency was observed in the case of HNO3-treated calcined biochar compared to the other treated biochars. Adsorption parameters of the calcined-acid treated biochar were optimized through response surface methodology. The maximum adsorption capacity of the calcined-acid treated biochar was 41.3 mg/g.