Yang Chuan Xi, Zhu Qing, Dong Wen Ping, Fan Yu Qi, Wang Wei Liang
School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China.
Shandong Research Center of Statistical Analysis of Science and Technology, Jinan 250101, China.
Langmuir. 2021 Aug 3;37(30):9253-9263. doi: 10.1021/acs.langmuir.1c01468. Epub 2021 Jul 21.
Phosphoric acid-modified biochar (PMBC) was prepared using biochar (BC) as the carbon source and phosphoric acid as the activating agent. The PMBC exhibited an ordered vessel structure after deashing treatment, but the sidewalls became much rougher, the polarity (O/C atomic ratio of BC = 0.2320 and O/C atomic ratio of PMBC = 0.1604) decreased, and the isoelectric points (PI of BC = 5.22 and PI of PMBC = 5.51) and specific surface area (SSA of BC = 55.322 m/g and SSA of PMBC = 62.285 m/g) increased. The adsorption characterization of the removal of sulfadiazine (SDZ) from PMBC was studied. The adsorption of SDZ by PMBC was in accordance with the Langmuir isotherm model and the pseudo-second-order kinetics model, and the adsorption thermodynamics were shown as Gibbs free energy < 0, an enthalpy change of 19.157 kJ/mol, and an entropy change of 0.0718 kJ/(K·mol). The adsorption of SDZ by PMBC was a complicated monolayer adsorption that was spontaneous, irreversible, and endothermic, and physical adsorption and chemical adsorption occurred simultaneously. The adsorption process was controlled by microporous capture, electrostatic interactions, hydrogen-bond interactions, and π-π interactions. PMBC@TiO photocatalysts with different mass ratios between TiO and PMBC were prepared the sol-gel method. PMBC@TiO exhibited both an ordered vessel structure (PMBC) and irregular particles (TiO), and it was linked Ti-O-C bonds. The optimal mass ratio between TiO and PMBC was 3:1. The removal of SDZ PMBC@TiO was dependent on the coupling of adsorption and photocatalysis. The PMBC-enhanced photocatalytic performance of PMBC@TiO resulted in a higher absorption of UV and visible light, greater generation of reactive oxygen species, high levels of adsorption of SDZ on PMBC, and the conjugated structure and oxygen-containing functional groups that promoted the separation efficiency of the hole-electron pairs.
以生物炭（BC）为碳源、磷酸为活化剂制备了磷酸改性生物炭（PMBC）。脱灰处理后的PMBC呈现出有序的容器结构，但侧壁变得更加粗糙，极性降低（BC的O/C原子比 = 0.2320，PMBC的O/C原子比 = 0.1604），等电点升高（BC的PI = 5.22，PMBC的PI = 5.51），比表面积增大（BC的SSA = 55.322 m²/g，PMBC的SSA = 62.285 m²/g）。研究了PMBC对磺胺嘧啶（SDZ）的吸附特性。PMBC对SDZ的吸附符合Langmuir等温模型和伪二级动力学模型，吸附热力学表现为吉布斯自由能＜0，焓变为19.157 kJ/mol，熵变为0.0718 kJ/(K·mol)。PMBC对SDZ的吸附是一个复杂的单层吸附过程，是自发、不可逆且吸热的，物理吸附和化学吸附同时发生。吸附过程受微孔捕获、静电相互作用、氢键相互作用和π-π相互作用控制。采用溶胶-凝胶法制备了TiO₂与PMBC质量比不同的PMBC@TiO₂光催化剂。PMBC@TiO₂既呈现出有序的容器结构（PMBC）又有不规则颗粒（TiO₂），且通过Ti-O-C键相连。TiO₂与PMBC的最佳质量比为3:1。PMBC@TiO₂对SDZ的去除取决于吸附与光催化的耦合作用。PMBC对PMBC@TiO₂光催化性能的增强导致其对紫外光和可见光的吸收更高，活性氧物种的生成更多，SDZ在PMBC上的吸附水平较高，以及共轭结构和含氧官能团促进了空穴-电子对的分离效率。
