ABSTRACT

A series of peanut shell (HS)-based biochar were prepared at different pyrolysis temperatures and subsequently used as the effective ozonation catalysts for ketoprofen (KET) degradation in aqueous solution. The physicochemical properties and morphology of the obtained biochar were analysed by ICP, TG, XRD, FT-IR, SEM, TEM, BET and etc. characterizations. The results demonstrated that the pyrolysis temperature played an important role on the structure and morphology of HS-based biochar. As the pyrolysis temperature increased, the cellulose and hemicellulose of HS gradually decomposed, resulting in the loss of biochar mass, improvement of the surface roughness, the increase of specific surface area, and the formation of new functional groups. The HS-based biochar pyrolyzed at 600°C (HS600) achieved the fast KET degradation rate with the pseudo-first-order rate constant of 0.922 min⁻¹ and the low adsorption rate of 1.3% in O₃/HS600 process. Meanwhile, the effects of the HS600 dosage, initial KET concentration, temperature, water matrix, and solution pH on KET degradation were systematically evaluated. Besides, the HS600 displayed great stability and reusability towards KET degradation during multiple cycling experiments. Moreover, the single oxygen, superoxide radical and hydroxyl radical were involved in O₃/HS600 process and the mechanisms for the improvement of KET degradation were also elucidated. It could be speculated that the enhancement of the catalytic ozonation by HS-based biochar was probably attributed to the increased active sites and the intense chemical bonds, and delocalized π electron.

摘要

在不同的热解温度下制备了一系列基于花生壳 (HS) 的生物炭，并随后将其用作在水溶液中降解酮洛芬 (KET) 的有效臭氧化催化剂。采用ICP、TG、XRD、FT-IR、SEM、TEM、BET等对所得生物炭的理化性质和形貌进行分析。表征。结果表明，热解温度对HS基生物炭的结构和形态具有重要影响。随着热解温度的升高，HS的纤维素和半纤维素逐渐分解，导致生物炭质量损失，表面粗糙度改善，比表面积增加，形成新的官能团。600℃热解的HS基生物炭（HS600）实现了快速的KET降解速率，准一级速率常数为0.922 min ^{-1 ，在O} ₃中的吸附率为1.3%/HS600 工艺。同时，系统评价了HS600用量、KET初始浓度、温度、水基质和溶液pH对KET降解的影响。此外，HS600 在多次循环实验中对 KET 降解表现出极大的稳定性和可重复使用性。此外，单氧自由基、超氧自由基和羟基自由基参与了O ₃ /HS600过程，并阐明了改善KET降解的机制。可以推测，HS 基生物炭对催化臭氧化的增强可能归因于活性位点的增加和强烈的化学键，以及离域的 π 电子。