A novel metal-organic framework-derived ZnO@ZIF-8 adsorbent with high efficiency for Pb (II) from solution: Performance and mechanisms

A metal-organic framework ([email protected]) with great adsorption potential was developed using ZnO nanoparticles as a surface-active center and applied to lead removal from wastewater. The adsorption experiments were carried out and the related adsorption behaviors were investigated. The adsorbent shows excellent adsorption performance between pH 3–5. The maximum adsorption capacity of [email protected] for Pb (II) was 689.36 mg/g at 303 K. The adsorptive process of Pb (II) onto [email protected] conforms to the Langmuir isotherm and pseudo-second-order kinetic models. Thermodynamics illustrate that the adsorption process is chemical adsorption on a uniform surface. Selectivity experiments showed that [email protected] had the strongest affinity with Pb (II). The adsorption-desorption cycle confirmed that [email protected] was a reliable and recyclable adsorbent. XPS, Zeta potential and FT-IR analysis illustrate that the adsorption of Pb (II) by [email protected] was concentrated in electrostatic adsorption and chelation. DFT calculation indicated that there are different types of Pb (II) combination mode (Pb-N and Pb-O) and the adsorption mainly depended on the chelation. This study presented herein played important roles in the governance of heavy metal waste-water pollution as a result of [email protected] can effective selectivity cleanup of Pb (II).