Department of Chemical Engineering, McGill University, 3610 University St., Montréal, H3A 0C5, Québec, Canada; Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Environmental Functional Materials and Water Treatment Laboratory, Department of Rural Systems Engineering, Seoul National University, Seoul, 08826, Republic of Korea.
Chemosphere. 2020 May;247:125811. doi: 10.1016/j.chemosphere.2020.125811. Epub 2020 Jan 10.
Microcystin-LR (MC-LR) is the most common cyanotoxin released from algal-blooms. The study investigated the MC-LR adsorption mechanisms by comparing adsorption performance of protonated mesoporous carbon/silica (MC-H, MS-H) and their amino-functionalized forms (MC-NH and MS-NH) considering surface chemistry and pore characteristics. The maximum MC-LR adsorption capacity (Langmuir model) of MC-H (37.87 mg/g) was the highest followed by MC-NH (29.25 mg/g) and MS-NH (23.03 mg/g), because pore structure is partly damaged during amino-functionalization. However, MC-NH (k = 0.042 g/mg/min) reacted faster with MC-LR than MC-H during early-stage adsorption due to enhancing electrostatic interactions. Intra-particle diffusion model fit indicated K of MC-H (2.11 mg/g/min) was greater than MC-NH due to its greater surface area and pore volume. Also, large mesopore diameters are favorable to MC-LR adsorption by pore diffusion. The effect of adsorbate molecular size on adsorption trend against MC-H, MC-NH and MS-NH was determined by kinetic experiments using two dyes, reactive blue and acid orange: MS-NH achieved the highest adsorption for both dyes due to the large number of amino groups on its surface (41.2 NH/nm). Overall, it was demonstrated that adsorption of MC-LR on mesoporous materials is governed by (meso-)pore diffusion and π - π (and hydrophobic) interactions induced by carbon materials; in addition, positively-charged grafted amino groups enhance initial MC-LR adsorption rate.
微囊藻毒素-LR（MC-LR）是从藻类水华释放的最常见的蓝藻毒素。本研究通过比较质子化介孔碳/硅（MC-H、MS-H）及其氨基功能化形式（MC-NH 和 MS-NH）的吸附性能，考虑表面化学和孔特征，研究了 MC-LR 的吸附机制。MC-H（37.87 mg/g）的最大 MC-LR 吸附容量（Langmuir 模型）最高，其次是 MC-NH（29.25 mg/g）和 MS-NH（23.03 mg/g），因为氨基功能化过程中部分破坏了孔结构。然而，由于增强了静电相互作用，MC-NH（k=0.042 g/mg/min）在早期吸附阶段比 MC-H 更快地与 MC-LR 反应。内颗粒扩散模型拟合表明，由于 MC-H 的比表面积和孔体积较大，K 为 2.11 mg/g/min，大于 MC-NH。此外，大的中孔直径有利于通过孔扩散进行 MC-LR 吸附。通过使用两种染料，活性蓝和酸性橙，在动力学实验中确定了吸附质分子大小对 MC-H、MC-NH 和 MS-NH 吸附趋势的影响：由于其表面大量的氨基（41.2 NH/nm），MS-NH 对两种染料的吸附效果最好。总的来说，研究表明，MC-LR 在介孔材料上的吸附受（中）孔扩散和碳材料诱导的π-π（和疏水）相互作用控制；此外，带正电荷的接枝氨基基团提高了初始 MC-LR 的吸附速率。
