Phloroglucinol (PG) is an extremely expensive pharmaceutical intermediate, which requires high purity for subsequent applications. Thus, there is a pressing need to selectively separate it from the complex production system. In this work, the optimal functional monomer N-Vinylimidazole (VIM) that possesses the strongest affinity with PG among 11 phenolic monomers was quantitively selected by DFT calculation. The key factors influencing the adsorption capacity (Qe) and imprinting effect (α) were systematically researched including the molar ratio of the template molecule (PG) to the functional monomer (VIM), the molar ratio of functional monomer to cross-linker (EGDMA), the types of solvent and the reaction time. And the physicochemical property and morphology of the obtained VIM-MIP with the best adsorption performance were explored by a series of characterization methods. The adsorption tests were carried out, indicating that the VIM-MIP exhibited large adsorption capability (Qe=81.34 mg/g), which exceeded 78.97% of existing optimal absorbents for PG. What’s more, the adsorption data for PG fit in with the Freundlich model (R2>0.99). More notably, the excellent PG selectivity of the VIM-MIP was confirmed by competitive adsorption experiments under binary systems (relative selectivity coefficient, 2.014), which was attributed to the existence of imprinted cavities. The molecular simulation, X-ray photoelectron spectroscopy (XPS) analysis and Zeta potential analysis were employed to reveal the adsorption mechanism, indicating the hydrogen bond was the main driving force.

Currently searching for effective noble metal separation material is generally blind and time-consuming. Although theoretical calculation has been widely applied to explain the adsorption mechanism, the quantitative coordination effect between ligand and metal remains to be explored especially in the material screening stage. In this study, Pearson's theory and Koopmans' theory were used to calculate the electron transfer ratio (& UDelta;N) from different ligands containing N, S, and O to PdCl2. The quantitative evaluation contributed to the design of efficient ligands including EA (& UDelta;N =0.5929), DB (& UDelta;N =0.5483), and AT (& UDelta;N =0.4885). And the corresponding polystyrene materials CMPS-EA, CMPS-AT, CMPS-DB were successfully synthesized via chemical modification. According to the adsorption experiment, the per mmol of ligand adsorption capacity from CMPSEA, CMPS-DB and CMPS-AT for Pd(II) were 0.67 mmol/mmol, 0.17 mmol/mmol and 0.11 mmol/mmol, respectively, exhibiting a positive correlation with the results of & UDelta;N. Moreover, CMPS-EA could efficiently remove 98.01% Pd(II) in the presence of multiple competing metal ions with five times concentration higher than Pd(II). In column study, the breakthrough point (Ct/C0 =0.05) for CMPS-EA was 666-676 BV in 1 mmol/L Pd(II) solution and up to 95% desorption efficiency within 50 BV. The adsorption differences and mechanism of CMPS-EA, CMPS-AT and CMPS-DB were further investigated by FTIR, XPS, ESP, and NBO.

Background: Furfurylamines are important components for the synthesis of many pharmacologically active compounds and polymers, but there is still a gap in the field of furfurylamine isolation.Method: In this study, we designed and synthesised a series of carboxy-modified multi-walled carbon nanotubes (MWCNTs) with four modification strategies (acidification, grafting, acidification and grafting, grafting and acidification). Grafting refers to the efficient radical polymerisation using the abundant double bonds on MWCNTs; acidification refers to the conversion of defective five-or seven-membered rings to carboxyl groups. In addition, the adsorption behaviors (static adsorption, thermodynamics, kinetics) of the new materials has been systematically investigated. Significant findings: Overall, grafting and acidification were the best strategies, with the MWCNTs-AA (MWCNTs grafted by acrylic acid) exhibiting an adsorption capacity (Qe) for furfurylamine of 133.16 mg/g. Subsequently, the acidified material MWCNTs-AA-COOH (Acidification of MWCNTs-AA)(Qe=176.29 mg/g) was obtained by response surface optimisation on a grafting basis. Qe of MWCNTs-AA-COOH was 59.3% higher than that of commercial materials. Thermodynamic data suggested that Langmuir equation could better describe the adsorption behaviors of MWCNTs-AA-COOH, indicating that the adsorption process was endothermic and chemisorbed (Qm=280.71 mg/g). Meanwhile, the kinetic adsorption could be better modeled by Pseudo-second-order equation, demonstrating the adsorption rate of MWCNTs-AA-COOH was faster. Overall, it was proved that we have successfully designed an efficient modification strategy for MWCNTs had been established, which could realize effective adsorption of furfuramine by ion exchange.