Assembly of Zr-MOF crystals onto magnetic beads as a highly adsorbent for recycling nitrophenol

Highly effective decontamination of nitrophenols from aqueous solution is a challenge for public health and ecosystem protection. Here we report the assembly of UiO-66 onto Fe3O4 particles by solvothermal method, formed durian-shaped magnetic porous composites (MSU(Zr)) with multi-core-shell structure. The weight ratio of UiO-66 shells and the Fe3O4 multi-core is about 6:4. MSU(Zr) performed well on 2-nitroresorcinol (NRC) adsorption, which could be attributed to the highly porosity and the nature of Lewis base of Zr6O4(OH)4 clusters. The equilibrium adsorption capacity for NRC is more than 200 mg g−1, which means that each Zr6O4 centre can uptake more than three NRC molecules (MSU(Zr)·3NRC). Kinetic parameters follow pseudo-second-order kinetics and Langmuir isotherm. pH value plays a significant role on NRC adsorption, which is more favor at acidic condition. It’s remarkable that the reversible adsorption-desorption performance could be adjust with pH. The reusability of MSU(Zr) shows a good recyclability that the adsorption capacity is still more than 180 mg g−1 after five regeneration cycles.