Synthesis of a nickel oxide infused biomass nanocomposites for enhanced cadmium ion removal from wastewater

Abstract

• Fabrication of nickel oxide nanocomposites using biomass materials • Characterization of the fabricated nanocomposites by various techniques • Isotherm and kinetics analysis of experimental data • Regeneration investigation of the studied nanocomposites • Proposed adsorption mechanism of Cd (II) onto respective nanocomposites The design and preparation of metal oxide infused green materials for effective treatment of heavy metals laden wastewater is essential for environmental safety and economic significance. In this report, low-cost agricultural wastes, corn silk (CS) and miracle leaves (ML) were synthesized using nickel oxide (NiO) to produce novel nanocomposites for elimination of Cd (II) ions from aqueous media. The nanocomposites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), thermogravimetric analysis (TGA).and Fourier transform infrared spectroscopy (FT-IR). The biosorption performance of Cd (II) onto NiO@CS and NiO@ML were 13.06 and 10.05 mg/g respectively under optimum conditions. Adsorption data fitted well with Langmuir isotherm for NiO@CS and Freundlich model for NiO@ML. The chemical adsorption performance was controlled by Pseudo-second order kinetics with high regression values (R 2 > 0.95) and lower chi-square values (ꭓ 2 = 0.002). Analysis of thermodynamics showed that the removal process was spontaneously feasible, endothermic and favorable. The regeneration study revealed a significant reuse of the nanocomposites and acceptable stability even after five period of cycles. The uptake system demonstrated a better affinity of Cd (II) ions by NiO@CS compared to NiO@ML nanocomposite. The mechanism of adsorption included chemisorption and then physisorption, with electrostatic interactions playing an important role. This study presents moderate valuable insights on feasibility of using the respective nanocomposites as promising eco-friendly adsorbents in environmental pollution remediation.