Lignin-based biochar with improved properties derived from the microbial combined chemical pretreatment of corn straw for efficient antibiotic removal

Abstract

In this study, straw lignin was separated from corn straw by combining microbial treatment with ρ-TsOH organic acid extraction for the first time, and lignin-derived biochars were prepared by carbonation-activation. The results showed that the extraction rate of lignin and the physicochemical properties of related biochars were improved greatly by microbial treatment. The specific surface areas of lignin biochar obtained after combined pre-treatment with Aspergillus niger, Myrothecium verrucaria, and Trichoderma reesei, (BNL, BML, and BTL) were 2348, 2849 and 3008 m² g⁻¹, respectively, and the total pore volumes were 0.8989, 0.9411, and 1.2621 cm³ g⁻¹, which were significantly higher than the 2292 m² g⁻¹ and 0.7786 cm³ g⁻¹ of the control group BCL (biochar prepared from lignin extracted from raw straw). In adsorption experiments by using tetracycline hydrochloride and sodium sulfadiazine as antibiotic models, the maximum adsorption capacities of all lignin-derived biochars (BML, BTL, and BNL) were greater than that of most other adsorbents including BCL. We hope this work could provide a new strategy for efficiently using microbial treatment technology to improve the conversion of lignocellulosic resources.