Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
Environ Sci Pollut Res Int. 2021 Mar;28(11):14028-14040. doi: 10.1007/s11356-020-11470-z. Epub 2020 Nov 17.
The adsorption behaviors of methylene blue (MB) on microalga residue powder (MRP) and biochars derived from microalga residue (MRB) produced at different pyrolytic temperatures were compared. Six biochars were prepared from residual Chlorella sp. and Spirulina sp. at different pyrolytic temperatures in the range of 200-550 °C. The adsorption kinetics, isotherms, thermodynamics, and the effect of pH were studied, and chemical analyses of MB-loaded MRP and MRB were conducted using SEM, FTIR, and XPS techniques. The results found that the pseudo-second-order, Elovich, and Freundlich models could effectively describe the MB adsorption process on MRP and MRB. The thermodynamic results confirmed that the adsorption processes were spontaneous and endothermic. Further, MRP showed an excellent adsorption ability on MB through electrostatic interaction, complexation with oxygen/nitrogen-containing functional groups and π-π interaction. However, massive oxygen-containing functional groups after pyrolysis were lost, leading to a significant decrease in the adsorption capacity of MRB on MB. This phenomenon was further observed with increasing pyrolytic temperature. Overall, this study demonstrated that microalga residue performed better for MB removal compared with their pyrolyzed analogs. Graphical abstract.
比较了微藻残渣粉末（MRP）和不同热解温度下由微藻残渣（MRB）制备的生物炭对亚甲基蓝（MB）的吸附行为。在 200-550°C 的范围内，用 SEM、FTIR 和 XPS 技术对从残留的 Chlorella sp. 和 Spirulina sp. 制备的六种生物炭进行了吸附动力学、等温线、热力学和 pH 值影响的研究。用 SEM、FTIR 和 XPS 技术对负载 MB 的 MRP 和 MRB 进行了化学分析。结果表明，准二级、Elovich 和 Freundlich 模型可以有效地描述 MB 在 MRP 和 MRB 上的吸附过程。热力学结果证实吸附过程是自发和吸热的。此外，MRP 通过静电相互作用、与含氧/含氮官能团的络合和π-π相互作用对 MB 表现出优异的吸附能力。然而，大量含氧官能团在热解后丢失，导致 MRB 对 MB 的吸附容量显著下降。随着热解温度的升高，这种现象进一步观察到。总的来说，这项研究表明，与热解类似物相比，微藻残渣对 MB 的去除效果更好。
