Preparation of mesoporous batatas biochar via soft-template method for high efficiency removal of tetracycline

In this contribution, we apply a soft-template-assisted hydrothermal route using polyethylene-polypropylene glycol (F127) as soft-template agent and biomass batatas as carbon precursor to synthesis a novel hydrothermal mesoporous biochar (HMC-800) for adsorptive removal of tetracycline (TC) from wastewater. We use the biochar prepared without F127 and direct pyrolytic biochar for comparison. The physicochemical properties of all the studied biochar samples are measured using a suite of characterization techniques. Our results show that the HMC-800 displays the highest specific surface area (286.3 m²/g) and total pore volume (0.249 cm³/g), manifesting the introduction of F127 can result in formation of well-developed pore structures. Regarding adsorption properties, the HMC-800 outperforms other biochar samples for TC removal. Our finding shows that solution with near-neutral pH is favorable for TC removal, and the highest adsorption capacity is observed at initial solution pH value 7. In addition, our findings show that applying the pseudo-second-order kinetic and Freundlich isotherm equation closely models the recorded adsorption behavior. The maximum adsorption capacity is measured to be as much as 238.7 mg/g by Langmuir isotherm model. Pore filling, hydrogen-bonding and n-π interaction are suggested to be the prevailing adsorption mechanisms compared to the other mechanisms. Furthermore, the HMC-800 performs better in regeneration and reuse experiments, making it a promising adsorbent material for TC removal from wastewater.