Characteristics and mechanisms of sulfamethoxazole adsorption onto modified biochars with hierarchical pore structures: Batch, predictions using artificial neural network and fixed bed column studies

A series of modified biochar with hierarchical pore structures (ZnxBC1, x = 0.5, 1, 2, 3) was obtained by ZnCl2 and investigated the adsorption performance of sulfamethoxazole (SMX). The structure and composition of ZnxBC1 were well characterized by the material analysis technique. Compared with unmodified biochar (BC), the specific surface area, pore volume, and adsorption capacity of ZnxBC1 significantly increased. The ZnxBC1 performed a significant adsorption capacity of SMX with the maximum adsorption amount of 597.57 mg/g, leading to a 54-fold increase in that of BC (11.04 mg/g). Multiple linear regression analysis showed that the quantitative relationship of q(e) with V-meso and V-micro was q(e) = 360.74*V-meso + 871.58*V-micro-22.26, which was the novelty of the study to the analysis of SMX adsorption capacity on the different V-meso/V-micro ratios of adsorbents. Based on the batch experiment results, an artificial neural network (ANN) model with a topology of 5:5:10:1 was developed to sufficiently describe the adsorption data (R-2 > 0.99), and possessed good predictability in different water quality conditions. Additionally, both static adsorption and dynamic adsorption experiments of Zn1BC1 showed excellent regeneration properties. Overall, the ZnCl2 modified biochar with the properties of rapid adsorption rate, high adsorption capacity, multiple reuses, and low-cost performed the potential utilization for the removal of SMX, and the effect of pore structure of biochar on SMX adsorption could guide the design and preparation of efficient antibiotics adsorbents.

Automated summary

A series of modified biochar with hierarchical pore structures were obtained by ZnCl2 and showed significantly increased adsorption capacity for sulfamethoxazole (SMX). The quantitative relationship between adsorption capacity and V-meso/V-micro ratios was determined. An artificial neural network model was developed to describe the adsorption data and showed good predictability. The ZnCl2 modified biochar exhibited potential utilization for SMX removal due to its rapid adsorption rate, high adsorption capacity, multiple reuses, and low cost, and the pore structure of biochar could guide the design of efficient antibiotics adsorbents.