Coal gasification fine slag based multifunctional nanoporous silica microspheres for synergistic adsorption of Pb(II) and Congo red

The discharge of large-scale industrial solid waste and wastewater has caused severe damage to environmental health. In this study, the adsorption behaviors of Pb(II) and Congo Red (CR) dye in single and binary aqueous systems were investigated using novel functionalized nanoporous glass microspheres (NGM). The NGM material was fabricated from coal gasification fine slag (CGFS) by a simple treatment and characterized using TG, BET, XRD, TEM, FT-IR, and XPS to analyze its physicochemical properties. The adsorption experiments showed that the adsorption amounts of DMA-NGM for Pb(II) and CR were 302.39 mg/g and 342.74 mg/g for the single systems, and 372.73 mg/g and 412.93 mg/g for the binary systems, respectively. The increased adsorption capacity was attributed to the synergistic effect of electrostatic attraction and chelation. Furthermore, the pseudo-second-order model and Elovich model could reasonably describe the adsorption of Pb(II) and CR on DMA-NGM. Pb(II) adsorption on DMA-NGM was monolayer adsorption and CR adsorption was multilayer adsorption. In summary, the results demonstrate the potential of efficient and environmentally friendly adsorbents for the resource recovery of CGFS and the processing of printing and dyeing wastewater.