中科院西北特色植物资源化学重点实验室/甘肃省天然药物重点实验室知识库

A novel magnetic adsorbent was designed and synthesized for adsorption and determination of hazardous aromatic acids (AAs) based on the zeolite imidazolate frameworks of Eu (ZIF-Eu), Fe₃O₄ and carboxyl multi-walled carbon nanotubes (MWCNTs-COOH). ZIF-Eu was fabricated for the first time, and Fe₃O₄ nanoparticles were encapsulated in MWCNTs-COOH, which made the separation procedure simple and easy-realizable. Adsorption experiments indicated that the adsorbent had superior affinity and selectivity to adsorbates with multi-ring, multi-carboxylic and electron-withdrawing group substituted structures, and it can achieve the selective adsorption of AAs from the aromatic mixture, the mechanism of which was evaluated and attributed to the intermolecular pi-pi electron-donor-acceptor (EDA) and hydrogen-bonding interactions. Seven AAs with different substituents were selected as target adsorbates to investigate the influences of critical experimental conditions on the adsorption efficiencies. Adsorption isotherms and kinetics were investigated and indicated that Dubinin-Ashtakhov model and pseudo-second-order model could well describe the adsorption of AAs on the nanocomposite. Adsorption thermodynamics study suggested that the adsorption reactions were spontaneous, endothermic and thermodynamically favorable. In addition, desorption conditions for AAs, and reusability of the novel adsorbent was evaluated, which confirmed the recyclability of the novel adsorbent.