Ultra-large adsorption capacity for tetracycline by defatted Schizochytrium limacinum residue biochar

Tetracycline (TC) is the one of the largest used antibiotics and its resulting water environment pollution has received widespread attention. In this paper, biochar was prepared by using the defatted Schizochytrium limacinum (microalgae) residue as raw material and KHCO 3 as activator, and its adsorption properties for TC were investigated. The results showed that KHCO 3 -activation biochar possessed the developed hierarchical porous structure. The specific surface area was up to 2295.26 m 2 ·g −1 , which was 409.6-fold higher than the pristine biochar. When the mass ratio of the pristine biochar to KHCO 3 was 1:1, the as-prepared biochar displayed the best adsorption performance for TC. The pseudo-second-order reaction kinetics can better describe the kinetic experiment results. The maximum adsorption capacity was 1357.5 mg·g −1 , which was more favorable than other biochar derived from agricultural waste reported previously. The adsorption capacity was stable under different solution conditions, suggesting that the microalgae residue-based biochar has a promising application foreground in wastewater treatment.