Green Chemistry Centre of Excellence, Department of Chemistry, University of York, York Y10 5DD, UK.
Green Chemistry Centre of Excellence, Department of Chemistry, University of York, York Y10 5DD, UK.
J Hazard Mater. 2022 Aug 15;436:129174. doi: 10.1016/j.jhazmat.2022.129174. Epub 2022 May 18.
Hierarchically porous activated Starbons® derived from starch are found to make excellent adsorbents for methylene blue, even in the presence of other dyes and inorganic salts, highlighting their potential to be used in water purification. The optimal material (S950C90) has a methylene blue adsorption capacity (891 mg g) almost nine times higher than that of unactivated S800 and four times higher than that of commercial activated carbon at 298 K. The adsorption of methylene blue onto optimal materials (S950C90 and S800K4) reaches equilibrium within 5 min. Adsorption data for all the adsorbents show a good fit to the Freundlich isotherm which allows the Gibbs free energies of adsorption to be calculated. The adsorption capacities increase as the pH of the methylene blue solution increases, allowing the dye to be desorbed by treatment with acidic ethanol and the Starbon® materials reused. Porosimetry and SEM-EDX imaging indicate that methylene blue adsorbs throughout the surface and completely fills all the micropores in the Starbon® adsorbent. The methylene blue adsorption capacities show excellent correlations with both the BET surface areas and the micropore volumes of the materials.
由淀粉衍生的具有层次多孔结构的活化 Starbons® 被发现是亚甲基蓝的极佳吸附剂，即使在存在其他染料和无机盐的情况下也是如此，这突出了它们在水净化中应用的潜力。最佳材料（S950C90）的亚甲基蓝吸附容量（891mg/g）比未活化的 S800 高近 9 倍，比商业活性炭在 298 K 时高 4 倍。亚甲基蓝在最佳材料（S950C90 和 S800K4）上的吸附在 5 分钟内达到平衡。所有吸附剂的吸附数据均很好地符合 Freundlich 等温线，从而可以计算出吸附的吉布斯自由能。吸附容量随亚甲基蓝溶液 pH 值的增加而增加，允许通过用酸性乙醇处理将染料解吸，并重复使用 Starbon®材料。孔隙率和 SEM-EDX 成像表明，亚甲基蓝吸附在整个表面上，并完全填充了 Starbon®吸附剂中的所有微孔。亚甲基蓝的吸附容量与材料的 BET 比表面积和微孔体积之间具有很好的相关性。
