A green approach to enhance the adsorption capacity: Synthesis of bamboo-based adsorbent by biological pretreatment

Biochar is a low-cost, environmentally friendly adsorbent used in the sewage treatment industry. In most cases, environmentally unfriendly chemical methods are employed when people make attempts to improve its adsorption properties. In this paper, a biological pretreatment method was used to degrade cellulose, which increases the controllable space of pore structure and the specific surface area of the material, thus improving its adsorption performance. Bamboo was first exposed to Trichoderma koningii for three weeks, which was followed by slow pyrolysis to produce biochar. Then, the carbon precursor was crushed and pyrolyzed using KOH to afford an adsorbent. The adsorbent was characterized by multiple approaches, and the adsorption of methylene blue (MB) on it was investigated in detail. In addition, the possible adsorption mechanism was also discussed. Compared with the MB adsorption capacity of the raw bamboo-derived biochar (9.92 mg/g), that of the newly developed adsorbent is enhanced by 25 times (248.57 mg/g), which is benefited from the pretreatment with Trichoderma koningii. And after 5 times of repeated recycling, the removal efficiency of 75.92% could still be maintained. It is expected that bamboo-based adsorbents prepared using Trichoderma koningii-treated bamboo will have a broad application prospect in the field of dye wastewater treatment.