Fe₃O₄/Halloysite nanotube magnetic composites (MHNTs) were firstly prepared via an effective polyol-medium solvothermal method, and then the surface of the MHNTs was endowed with reactive vinyl groups through modification with 3-(methacryloyloxy)propyl trimethoxysilane (MPS). Based on the MHNTs-MPS, temperature responsive and magnetic molecularly imprinted polymers (t-MMIPs) were further synthesized by adopting methacrylic acid (MAA) and N-isopropylacrylamide (NIPAM) as the functional monomer and temperature responsive monomer, respectively. The as-prepared t-MMIPs were characterized by FT-IR, TEM, TGA and VSM, which indicated that the t-MMIPs exhibit magnetic sensitivity (M_s = 2.026 emu g⁻¹), magnetic stability (especially in the pH range of 4.0–8.0) and thermal stability and are composed of an imprinted layer. The molecular interaction between 2,4,5-trichlorophenol (TCP) and MAA was investigated by ¹H-NMR spectroscopy and ultraviolet absorption spectroscopy, which suggest that hydrogen bonding may be largely responsible for the recognition mechanism. The t-MMIPs were then applied to selectively recognise and release TCP molecules at 60 °C and 20 °C, respectively. The maximum amount of binding at 60 °C was 197.8 mg g⁻¹ and 122.6 mg g⁻¹ for t-MMIPs and temperature responsive and magnetic non-imprinted polymers (t-MNIPs), respectively. At 20 °C, about 32.3%–42.7% of TCP adsorbed by t-MMIPs was released, whereas 25.3%–39.9% of TCP was released by t-MNIPs. The selective recognition experiments demonstrated the high affinity and selectivity of t-MMIPs towards TCP over competitive phenolic compounds, and the specific recognition of binding sites may be based on the distinct size, structure and functional group to the template molecules.

Metal–organic framework (MOF) materials are a class of hybrid organic–inorganic supramolecular materials. Owing to their highest specific surface area, lowest crystal density and adjustable pore size and functional structure, MOF materials have the potential for some special applications in the field of adsorption of heavy metal contaminants. However, it is difficult to collect and reuse them in adsorption separation because of their nanometer size. Therefore, graphene oxide (GO) with good film-forming properties is used. In this paper, an f-ZIF-8@GO composite membrane material was developed by using GO and a zeolitic imidazolate framework (ZIF-8) material and was modified with 3-aminopropyl-triethoxysilane (APTES) by amine functionalization. After a series of structural characterizations, it was applied to the adsorption of copper ions in water and its adsorption properties were tested. The results showed that the adsorption capacity at pH = 6.0 was the largest, and an increase in temperature was not conducive to the adsorption reaction. The adsorption data were fitted to the Freundlich equation and the quasi-second order kinetic equation. The adsorption of Cu²⁺ on water was multilayer, and the equilibrium adsorption capacity was up to 1872.24 mg g⁻¹. The prepared materials exhibited high selectivity to copper ions; they could be reused as adsorbents for many times and maintained high adsorption capacity. This kind of material is of great significance for the adsorption and separation of heavy metal ions in water.