Hubei Key Laboratory of Mineral Resources Processing and Environment, School of Resources and Environmental Engineering, State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China.
China-UK Water and Soil Resources Sustainable Utilization Joint Research Centre, Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China.
Sci Total Environ. 2020 May 20;718:137299. doi: 10.1016/j.scitotenv.2020.137299. Epub 2020 Feb 13.
A novel adsorbent of sludge biochar (SBC) and multi-walled carbon nanotube (CNT) composite was synthesized (CNT-SBC) to remove low concentrations of sulfamethoxazole (SMX) from water. The key factors of dose, contact time, pH and temperature were investigated. Higher dose of adsorbents provided more active sites for SMX adsorption. The effect of pH was due to the electrostatic interaction. Increasing the temperature was beneficial to SMX adsorption, which was a spontaneous endothermic process and the strength of the spontaneous increased with CNT supporting. As pseudo-second-order, Elovich, Langmuir and Freundlich models fitted the experimental data better, this suggested that both physisorption and chemisorption played vital roles during the adsorption process. In addition, liquid film diffusion was the main rate-limiting step of adsorption. Compared with SBC (5.43 × 10 μg g), CNT-SBC-1 (CNT:SBC = 1:2), CNT-SBC-2 (CNT:SBC = 1:4) and CNT-SBC-3 (CNT:SBC = 1:6) exhibited better adsorption performance with up to 2.35 × 10, 1.49 × 10 and 1.22 × 10 μg g at 25 °C, respectively. The characterization analysis demonstrated that the stronger adsorption capacity of CNT-SBC was mainly attributed to the pore filling, functional groups complexation and π-π interaction. In summary, as an efficient and environment-friendly adsorbent, CNT-SBC has promising potential for low concentrations of SMX and other emerging contaminants removal from water.
一种新型的污泥生物炭（SBC）和多壁碳纳米管（CNT）复合材料吸附剂（CNT-SBC）被合成出来，用于从水中去除低浓度的磺胺甲恶唑（SMX）。考察了剂量、接触时间、pH 值和温度等关键因素。更高剂量的吸附剂为 SMX 的吸附提供了更多的活性位点。pH 的影响归因于静电相互作用。升高温度有利于 SMX 的吸附，这是一个自发的吸热过程，随着 CNT 的支撑，自发的强度增加。准二级、Elovich、朗缪尔和弗罗因德利希模型更能拟合实验数据，这表明物理吸附和化学吸附在吸附过程中都起着重要作用。此外，液膜扩散是吸附的主要速率限制步骤。与 SBC（5.43×10μg/g）相比，CNT-SBC-1（CNT：SBC=1：2）、CNT-SBC-2（CNT：SBC=1：4）和 CNT-SBC-3（CNT：SBC=1：6）在 25℃时表现出更好的吸附性能，分别高达 2.35×10、1.49×10和 1.22×10μg/g。特征分析表明，CNT-SBC 较强的吸附能力主要归因于孔填充、官能团络合和π-π相互作用。总之，作为一种高效、环保的吸附剂，CNT-SBC 有望用于去除水中低浓度的 SMX 和其他新兴污染物。
