Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
Sci Total Environ. 2021 Apr 1;763:143028. doi: 10.1016/j.scitotenv.2020.143028. Epub 2020 Oct 21.
The growing incidence of microcystins (MCs) in the environment has become an issue of global concern for the high ecological and human health risks. Herein, a comparative adsorption of three MCs (MC-LR, MC-YR and MC-RR) by spent mushroom substrate (SMS)-derived biochars from contrasting pyrolytic conditions (temperature: 600/300 °C; and gas steam: CO2/N2) was surveyed to better understand the mechanisms and factors affecting the adsorption performance. For biochar preparation, 600 °C and CO led to greater levels of aromaticity, ash, S, and porosity, while 300 °C and N created more surface functional groups. The adsorption of MCs by biochars was a pH-dependent and endothermic physisorption process, following the pseudo-second-order kinetics (R = 0.99) and linear isotherm model (R > 0.88). The distribution coefficients K (0.98-19.2 L/kg) varied greatly among MCs (MC-YR > MC-RR > MC-LR) and biochars (BC600 > BN600 > BC300 > BN300), which depends on the combined effects of hydrophobicity, electrostatic attraction, H-bonding, cation bridging, and the amounts of adsorption sites on biochars. Higher ash, S, and total pore volume of BC600 facilitated the adsorption capacity for MCs relative to other biochars. Furthermore, the co-adsorption efficacy for MCs (K = 1.09-8.86 L/kg) was far below those for the single adsorption, indicating strong conflicts among competing MCs. This study sheds light on the roles of pyrolytic temperature and gas steam in biochar properties, and elucidates the mechanisms and factors affecting the adsorption performance of different MCs, which lays a foundation for MCs removal from water.
环境中微囊藻毒素（MCs）的发生率不断增加，对生态和人类健康构成了高风险，已成为全球关注的问题。在此，通过对比热解条件（温度：600/300°C；气体蒸汽：CO2/N2）下制备的不同生物炭，研究了废弃蘑菇基质（SMS）衍生生物炭对三种 MCs（MC-LR、MC-YR 和 MC-RR）的吸附作用，以更好地了解影响吸附性能的机制和因素。对于生物炭的制备，600°C 和 CO 导致芳香度、灰分、S 和孔隙率增加，而 300°C 和 N 则产生更多的表面官能团。MCs 的吸附是一个依赖于 pH 的、吸热的物理吸附过程，遵循准二级动力学（R²=0.99）和线性等温模型（R²>0.88）。MCs 在生物炭上的分配系数 K（0.98-19.2 L/kg）在 MCs（MC-YR>MC-RR>MC-LR）和生物炭（BC600>BN600>BC300>BN300）之间差异很大，这取决于生物炭上的疏水性、静电引力、氢键、阳离子桥接和吸附位点数量的综合作用。BC600 较高的灰分、S 和总孔体积有助于其对 MCs 的吸附能力相对于其他生物炭。此外，MCs 的共吸附效率（K=1.09-8.86 L/kg）远低于单一吸附的效率，表明竞争 MCs 之间存在强烈的冲突。本研究揭示了热解温度和气体蒸汽在生物炭性质中的作用，并阐明了影响不同 MCs 吸附性能的机制和因素，为从水中去除 MCs 奠定了基础。
