Tuneable functionalized biochar for simultaneous removal of pharmaceuticals from binary mixture

Abstract

Eliminating different pharmaceutical contaminants simultaneously from wastewater has become a crucial environmental issue. In this regard, the scientific shift from the conventional methods of removing single pollutants to implementing a system that simultaneously removes multiple contaminants is required. In pursuit of this goal, functionalized biochar (FBC) was prepared from bamboo sawdust to simultaneously remove pharmaceutical pollutants in batch and fixed-bed sorption systems. FBC exhibited a greater removal capacity for acetaminophen (ACM) (192.43 mg/g) compared to ciprofloxacin (CIP) (70.95 mg/g), as predicted by the Langmuir isotherm model. The competitive Langmuir isotherm model, employed for the binary component, predicted a maximum adsorption capacity of 125.31 mg/g for ACM and 65.44 mg/g for CIP. The adsorption capacity ratio (qm binary/qm single < 1) suggests an antagonistic behavior of these pollutants when they co-exist in the water matrix. On the other hand, the single and binary component adsorption of ACM and CIP was best described by the pseudo-second order kinetic model, indicating that the adsorption process was mainly controlled by the chemisorption process. Fixed-bed column study showcased the maximum bed capacity of ACM (172.48 mg/g) and CIP (147.67 mg/g), with the highest respective removal efficiency of 44.23% and 37.86% in the binary component adsorption system. However, the single-component column adsorption system achieved a higher removal efficiency of 65.83% (ACM) and 42.59% (CIP). These results indicate that the simultaneous removal of ACM and CIP depends on the unique molecular properties of the ACM/CIP and their interactions with the adsorbent. Hence, the as-synthesized FBC has been proven effective performance for the simultaneous removal of ACM and CIP from various water matrices.

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