Regenerable zeolitic imidazolate frameworks@agarose (ZIF-8@AG) composite for highly efficient adsorption of Pb(II) from water

The composite zeolitic imidazolate frameworks@agarose (ZIF-8@AG) was prepared by ZIF-8 and agarose (AG) in this study. The composite ZIF-8@AG with a good quality, was assessed for Pb(II) adsorption and regeneration from water. The effects of the contact time, initial concentration of Pb(II), adsorbent dosage, pH, coexisting ions (Ca2+ and Mg2+), temperature and other factors on the adsorption performance of Pb(II) on ZIF-8@AG were investigated. The pseudo-second-order kinetic model can well describe the adsorption process of Pb(II) on ZIF-8@AG. Thermodynamic parameters (Delta G, Delta H and Delta S) confirmed exothermic and spontaneous process. In the regeneration experiment, ZIF-8@AG maintained a high adsorption capacity for Pb(II) after 6 times of adsorption-desorption cycles. The experimental results showed that the ZIF-8@AG not only has a high adsorption efficiency for Pb(II), but also has a good stability for recycling.