College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
Molecules. 2023 Apr 11;28(8):3353. doi: 10.3390/molecules28083353.
The design and preparation of cheaper, greener and more efficient adsorbents is essential for the removal of pollutants by adsorption. In this study, biochar was prepared from peel of Brassica juncea var. gemmifera Lee et Lin (PoBJ) using a facile, low-temperature and vacuum pyrolysis, and the adsorption mechanism toward organic dyes in aqueous solution was elucidated. The adsorbent was characterized by XPS, FT-IR and SEM, and zeta potential techniques. The adsorption ability of PoBJ biochar for cationic dyes (methylene blue, brilliant green, calcein-safranine, azure I, rhodamine B), anionic dyes (alizarin yellow R), and neutral dyes (neutral red) revealed that the biochar exhibited adsorption selectivity toward cationic dyes. The effects of different factors on the adsorption performance of PoBJ biochar, as well as the adsorption kinetics and thermodynamics, were further investigated by using methylene blue as the model adsorbate. These factors included temperature, pH, contact time and dye concentration. The experimental results showed that BJ280 and BJ160 (prepared at 280 °C and 160 °C, respectively) possessed relatively higher adsorption capacity of 192.8 and 167.40 mg g for methylene blue (MB), respectively, demonstrating the possibility of utilization of PoBJ biochar as a superior bio-adsorbent. The experimental data of BJ160 toward MB were correlated with various kinetic and isothermal models. The results indicated that the adsorption process was consistent with the Langmuir isotherm model and nonlinear pseudo-second-order kinetic model. Thermodynamic parameters indicated that the adsorption of MB onto BJ160 was exothermic. Thus, the low-temperature prepared PoBJ biochar was an environmentally friendly, economic and efficient cationic dye adsorbent.
制备更廉价、绿色和高效的吸附剂对于吸附去除污染物至关重要。本研究使用简便、低温和真空热解的方法，从 Brassica juncea var. gemmifera Lee et Lin（PoBJ）的果皮中制备生物炭，并阐明了其在水溶液中对有机染料的吸附机制。通过 XPS、FT-IR 和 SEM 以及动电电位技术对吸附剂进行了表征。PoBJ 生物炭对阳离子染料（亚甲蓝、亮绿、钙黄绿素-藏红、天青 I、罗丹明 B）、阴离子染料（茜素黄 R）和中性染料（中性红）的吸附能力表明，生物炭对阳离子染料具有吸附选择性。进一步以亚甲蓝为模型吸附质，考察了不同因素（温度、pH 值、接触时间和染料浓度）对 PoBJ 生物炭吸附性能的影响，以及吸附动力学和热力学。实验结果表明，分别在 280°C 和 160°C 下制备的 BJ280 和 BJ160 对亚甲蓝（MB）的吸附容量分别为 192.8 和 167.40mg/g，表明 PoBJ 生物炭作为一种优良的生物吸附剂具有潜在的应用价值。BJ160 对 MB 的实验数据与各种动力学和等温模型相关联。结果表明，吸附过程符合 Langmuir 等温模型和非线性拟二级动力学模型。热力学参数表明，MB 吸附到 BJ160 上是放热的。因此，低温制备的 PoBJ 生物炭是一种环境友好、经济高效的阳离子染料吸附剂。
