Distillers’ grains biochar derived iron catalyst for remediation of tetracycline contamination: Performance and mechanism

Abstract

Distiller's grains (DGs) are the solid wastes generated during the manufacture process of Chinese liquor. It is crucial for the liquor industry to realize the resource utilization of DGs for accomplishing a sustainable development. Herein, a novel iron catalyst was fabricated by anchoring porous zero-valent iron (Fe⁰) with high accessibility onto the DGs biochar (DB). The as-prepared DGs biochar-anchored porous iron (DB@Fe) demonstrated exceptional capability for the remediation of tetracycline (TC) contamination in water, which provided the removal rate of TC as high as 92.15 %, showing 1.43-fold higher TC degradation capability than the pristine Fe⁰ owing to the porous Fe⁰ enabled facile accessibility to TC. Moreover, the abundant oxygen-containing functional groups of DB were able to effectively suppress the leakage of anchored porous Fe⁰ from the DB@Fe, which therefore provided a low iron loss rate of only 3.26 % during the degradation process. The DB@Fe also demonstrated its cycling capability by providing the TC removal rate of 65.45 % in the 5th cycle. The DB@Fe still achieved the TC removal rate of 72.81 % in the presence of NaCl at the high concentration of 50 g L⁻¹, which demonstrated the potential utilization of DB@Fe for the remediation of TC contamination in mariculture wastewater. High-performance liquid chromatography analyses revealed that the DB@Fe enabled a synergistic remediation of adsorption-degradation process for TC contamination in water.