School of Chemistry and Chemical Engineering, Henan Key Laboratory of Coal Green Conversion, Henan Polytechnic University, Jiaozuo, 454000, China.
Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Jiaozuo, 454000, China.
Environ Sci Pollut Res Int. 2022 Oct;29(47):72001-72016. doi: 10.1007/s11356-022-20986-5. Epub 2022 May 24.
The development of efficient, recyclable, and environment-friendly adsorbent for wastewater remediation is considered a challenge. In this study, a hierarchical porous kaolinite microsphere (HPKS) with three-dimensional (3D) structure was fabricated based on natural-layered kaolinite mineral via an environmentally friendly direct hydrothermal strategy. Characterization results revealed that HPKS microsphere with 3D hierarchical porous structure was constructed with numerous nanospheres which are assembled by ultrafine aluminosilicate flakes. HPKS exhibited negative charge feature ranging from strong acid to high alkaline solution. The influence of contact time, solution pH, initial dye concentration, adsorbent dosage, and foreign ions on methylene blue (MB) adsorption capability was systematically investigated. The synthesized HPKS with higher specific surface area (250.6 m/g) shows an outstanding adsorption capacity towards MB (411.8 mg/g) and excellent selectivity for cationic MB dyes over anionic methyl orange and competitive metal ions. The adsorption kinetic experiment results fit very well with the pseudo-second-order model and reflect the fast adsorption rate of MB on HPKS. The sorption isotherm study reveals the chemisorption of electrostatic attraction between the cationic MB molecules and the negative charged surfaces of HPKS. More importantly, the MB removal efficiency is more than 99% in a broad range of solution pH value. The adsorption capacities of HPKS can be easily recovered by calcination at 600 °C to remove the adsorbed dyes and without obvious diminishment even after six successive cycles. Therefore, the HPKS is a cost-effective and environmentally friendly adsorbent which has is promising to use in practical applications.
开发高效、可回收且环境友好的废水处理吸附剂被认为是一项挑战。在本研究中，通过一种环保的直接水热策略，以天然层状高岭土矿物为原料，制备了具有三维（3D）结构的分级多孔高岭土微球（HPKS）。表征结果表明，具有 3D 分级多孔结构的 HPKS 微球由许多纳米球组装而成，这些纳米球由超细微的铝硅酸盐片组成。HPKS 表现出从强酸到高碱性溶液的带负电荷特征。系统研究了接触时间、溶液 pH 值、初始染料浓度、吸附剂用量和共存离子对亚甲基蓝（MB）吸附能力的影响。合成的具有较高比表面积（250.6 m/g）的 HPKS 对 MB（411.8 mg/g）具有出色的吸附能力，并且对阳离子 MB 染料具有优异的选择性，超过了阴离子甲基橙和竞争金属离子。吸附动力学实验结果非常符合准二级模型，反映了 MB 在 HPKS 上的快速吸附速率。吸附等温线研究表明，阳离子 MB 分子与 HPKS 带负电荷表面之间存在静电吸引的化学吸附。更重要的是，在很宽的溶液 pH 值范围内，MB 的去除效率超过 99%。吸附在 HPKS 上的染料可以通过在 600°C 下煅烧轻松回收，并且即使经过六次连续循环，吸附容量也没有明显下降。因此，HPKS 是一种具有成本效益且环境友好的吸附剂，有望在实际应用中使用。
