Microwave-assisted synthesis of porous graphitized biochar as a super sorbent for tetracycline separation

Porous graphitized biochar was synthesized from waste coconut shell utilizing microwave-assisted pyrolysis, with combination of KOH and KCl as activators. The activators s not only facilitated creation of porous and graphitized structure with high surface area, but also reduced the KOH corrosion as an impeding factor against KOH activation. The process further facilitates easy recovery and reuse of KCl for economic benefits. The biochar has few layers graphene structure and abundant pores with specific surface area of 2047 m²·g⁻¹ and excellent adsorption capacity for tetracycline. An adsorption capacity as high as of 1033.06 mg·g⁻¹, is phenomenal, not reported in open literature, which could be attributed to the adsorption mechanism of pore filling, electrostatic attraction, hydrogen bonding and π-π interaction. The work authenticates utilization of porous graphitized biochar as a novel adsorbent for treatment of wastewater streams with antibiotics, and an economical commercial alternative to the existing processes and adsorbents.