Selective and enhanced nickel adsorption from sulfate- and calcium-rich solutions using chitosan

Abstract

Highlights• Chitosan effectively adsorbed Ni from a real Ni/Ca/SO4 2bearing leachate • Sulfate had a positive effect on Ni adsorption while Ca did not have any effect• Formation of NiSO4 0 species contributed to the enhanced Ni adsorption onto chitosan • Chitosan has a Ni qmax of 1.49 mmol/g even with 500 mM SO4 2and 10 mM Ca present • Chitosan was selective for Ni over Ca as validated in a column setup ABSTRACT Nickel (Ni) is an economically important metal characterized by its mechanical strength and anticorrosion properties. With the increasing industrial demand for Ni and the depleting accessible Ni primary ores, sustainable technologies are required for the recovery of this metal from alternative resources. In this study, adsorption using chitosan was investigated as a sustainable technique to recover Ni from sulfate (SO4 2-) and calcium (Ca) rich secondary resources. The effects of pH, contact time, and the presence of SO4 2and Ca on Ni adsorption were investigated in batch experiments. Chemical speciation modeling was performed to analyze how the predominant Ni species present under different conditions may affect the efficiency of the adsorption process. The comparison of chitosan's maximum Ni adsorption capacities in the absence (1.00 mmol/g) and presence (1.49 mmol/g) of 500 mM SO4 2and 10 mM Ca indicated the positive effect of these ions on Ni adsorption. The predominance of the neutrally charged NiSO4 0 species in Ni/SO4 2system has contributed to the enhanced Ni adsorption on chitosan as verified by X-ray photoelectron spectroscopy (XPS) analysis.However, kinetic studies confirmed that the Ni adsorption rate decreased by 4.5 times when SO4 2was present. The subsequent continuous Ni adsorption from a real SO4 2--rich leachate in a column setup revealed that chitosan is selective for Ni over Ca and Cr with selectivity quotients of 9.6 (KNi/Ca) and 3.0 (KNi/Cr). Overall, this study indicated that Ni complexation with SO4 2enhances the Ni adsorption capacity of chitosan, but slows down the adsorption process.

Hybrid Chitosan/CaO-Based Nanocomposites Doped with Plant Extracts from Azadirachta indica and Melia azedarach: Evaluation of Antibacterial and Antibiofilm Activities

“…The formation of the unloaded sample is shown in the range of 800-1200 cm − 1 by a complex group of absorption bands. The strong peak at 1059 cm-1 appearing in both CS-Ca and loaded nanocomposites was generally ascribed to the saccharide framework of the chitosan, also coincided with the vibration of Ca-O linkage through the chitosan matrix [37].…”

Preparation and characterization of pH-responsive metal-polyphenol structure coated nanoparticles

“…9e), and N 1s spectrum includes two peaks N-H (401.45 eV) and C-N-C (399.51 eV) (Fig. 9f) [26] . After modification with TA and Fe 3+ , a weak Fe signal peak appeared at 702.94 eV.…”

“…In addition, compared with zein-Fe III , zein-CQDs-Fe III and zein-PTN-Fe III , the curves of zein-PTN-CQDs-Fe III nanoparticles showed a new small peak at 58.72°. The emergence of new peaks indicated that intermolecular interactions occured between FeCl 3 , TA, zein, PTN and CQDs, and the intermolecular interactions changed the physical states of each substance before the reaction [26] . The above results indicated that zein-PTN-CQDs nanoparticles could be formed by adding FeCl 3 and TA based on intermolecular interaction.…”

The simultaneous and synergistic sorption of phenanthrene and cadmium using biomass derived from rice roots

“…The interaction of heavy metal cations, e.g., Cd 2+ , with biological components typically contributes to surface functional groups, e.g., hydroxyl and carboxyl groups (-COOH at 1737 cm -1 and -OH at 3334 cm -1 , as shown in Fig. 1) (Nicomel et al 2021). The sorbed coexisting cadmium on the surface groups of the RRB provided extra sorption sites for PHE through n-π interactions, resulting in synergistic sorption for PHE (Xiao et al 2007).…”