Suner Selin S, Demirci Sahin, Sutekin Duygu S, Yilmaz Selehattin, Sahiner Nurettin
Department of Chemistry & Nanoscience and Technology Research and Application Center, Canakkale Onsekiz Mart University Terzioglu Campus, Canakkale 17100, Turkey.
Department of Chemistry, Hacettepe University, Beytepe, Ankara 06800, Turkey.
Micromachines (Basel). 2022 Jun 13;13(6):938. doi: 10.3390/mi13060938.
A thiourea hexamethylene diisocyanate covalent organic framework (TH COF) was synthesized by adjusting the surface charge and surface area. The surface charge value of TH COF, −3.8 ± 0.5 mV, can be changed to −29.1 ± 0.4 mV by treatment with NaOH (dp-TH) and 17.1 ± 1.0 mV by treatment with HCl (p-TH). Additionally, the surface area of TH COF was 39.3 m2/g, whereas the surface area of dp-TH COF and p-TH COF structures were measured as 41.4 m2/g and 42.5 m2/g, respectively. However, the COF structure had a better adsorption capability with acid and base treatments, e.g., dp-TH COF absorbed 5.5 ± 0.3 mg/g methylene blue (MB) dye, and p-TH COF absorbed 25.9 ± 1.4 mg/g methyl orange (MO) dye from 100 mL 25 ppm aqueous dye solutions, thereby increasing the MB and MO absorption amounts of the TH COF structure. Furthermore, by calculating the distribution, selectivity, and relative selectivity coefficients, the absorption capacity order was determined as dp-TH > TH > p-TH COFs for the MB dye, whereas it was p-TH > TH > dp-TH COFs for the MO dye. Finally, the reusability of dp-TH COF for MB absorption and p-TH COF for MO absorption were investigated. After five repeated uses, dp-TH COF retained 64.6 ± 3.7% of its absorption ability, whereas p-TH COF preserved 79.7 ± 3.2% of its absorption ability relative to the initial absorption amount.
通过调节表面电荷和表面积合成了一种硫脲六亚甲基二异氰酸酯共价有机框架（TH COF）。TH COF的表面电荷值为−3.8 ± 0.5 mV，用NaOH处理（dp - TH）后可变为−29.1 ± 0.4 mV，用HCl处理（p - TH）后变为17.1 ± 1.0 mV。此外，TH COF的表面积为39.3 m²/g，而dp - TH COF和p - TH COF结构的表面积分别测定为41.4 m²/g和42.5 m²/g。然而，经过酸碱处理后，COF结构具有更好的吸附能力，例如，dp - TH COF从100 mL 25 ppm的水性染料溶液中吸附了5.5 ± 0.3 mg/g的亚甲基蓝（MB）染料，p - TH COF吸附了25.9 ± 1.4 mg/g的甲基橙（MO）染料，从而增加了TH COF结构对MB和MO的吸附量。此外，通过计算分布系数、选择性系数和相对选择性系数，确定了MB染料的吸附容量顺序为dp - TH > TH > p - TH COF，而MO染料的吸附容量顺序为p - TH > TH > dp - TH COF。最后，研究了dp - TH COF对MB吸附和p - TH COF对MO吸附的可重复使用性。经过五次重复使用后，相对于初始吸附量，dp - TH COF保留了其吸附能力的64.6 ± 3.7%，而p - TH COF保留了其吸附能力的79.7 ± 3.2%。
