Efficient treatment of smelting wastewater: 3D nickel foam @MOF shatters the previous limitation, enabling high-throughput selective capture of arsenic to form non-homogeneous nuclei

Abstract

A significant challenge in environmental remediation involves designing adsorbents that can effectively remove arsenic from smelting wastewater. This study aimed to address issues related to Metal-Organic Framework (MOF) pore blockage and insufficient active sites. To do this, we prepared MIL-101(Fe) and MIL-101(Cr) directly on three-dimensional nickel foam (NF) using a sustainable hydrothermal one-pot method. Using the NF as a carrier allowed for a uniform distribution of MIL-101(Fe) and MIL-101(Cr). This increased their contact area with the solution and enhanced the exposure of active sites. We investigated the adsorption capacities of trivalent and pentavalent arsenic by NF/MOFs through experiments and computational simulations. Our findings indicated that NF/MIL-101(Fe) and NF/MIL-101(Cr) adsorbed arsenic at concentrations of 152.65 mg/g and 132.615 mg/g, under conditions of room temperature and pH levels of 7 and 4, respectively. Analysis of the adsorption kinetics and thermodynamics revealed that the adsorption process for both adsorbents was chemical in nature, with monolayer adsorption being predominant. Molecular dynamics results indicated diffusion coefficients of 0.556667 × 10–6 for Fe3+ ions and 0.44 × 10–6 for Cr3+ ions. This suggests that NF/MIL-101(Fe) has a strong adsorption capacity. The proposed adsorption site model accurately predicted arsenic adsorption on the NF/MIL-101(Cr) and NF/MIL-101(Fe) structures. Given these properties, NF/MIL-101(Cr) and NF/MIL-101(Fe) are versatile materials with specificity and storage capacity for arsenic removal from smelting wastewater. Their potential in industrial wastewater purification is promising.