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Copper is one of the toxic heavy metal, it has to be eliminated from the polluted environment. Thus, the present work was aimed to prepare glutaraldehyde crosslinked chitosan oligosaccharide (COS)-based binary and ternary blend using carboxymethyl starch (CMS) and kaolin clay (KC) and applied as a sorbent for copper(II) ions to overcome excessive heavy metal pollution. Initially, the binary and ternary blends are prepared using sol–gel method and then examined for its formation and suitability for adsorption using FTIR, XRD, BET, Zeta potential and SEM studies. The prepared COS/CMS and COS/CMS/KC blends demonstrated outstanding adsorption properties for the arrest of Cu2+ ion. The adsorption efficiency of the prepared binary and ternary blends was examined through batch mode, and the experimental data were fitted with Langmuir and Freundlich isotherm models and kinetic models. The obtained results revealed that the Langmuir model showed better fit for binary blend and for ternary blend Freundlich isotherm model showed better fit through the highest R2 values. The maximum adsorption capacity was 98.91 mg/g and 132.45 mg/g for binary and ternary blends, respectively. [ABSTRACT FROM AUTHOR]

Recently, 3D cryogels with the interconnected macropore structure have gained great attention owing to their immense application potential in wastewater cleanup. Here, we fabricated a pure poly(vinyl imidazole) cryogel through improved cryogelation method, adding the pre-freezing–thawing step, which reduced the temperature difference between the different positions of the precursor solution during reaction. Compression experiments showed that the prepared 3D cryogel featured a robust underwater elastic performance. The adsorption capacity of Cu(II), Ni(II), Zn(II), Co(II), Pb(II), and Cd(II) ions from aqueous solutions by the poly(vinyl imidazole) cryogel was explored. The results showed the specific adsorption of Cu(II), in which the adsorption capacity and removal efficiency reached 148 mg/g and 99.99%, respectively. The adsorption capacity was 58 times higher than that of the reported poly(vinyl imidazole) cryogel which was prepared using hydroxyethyl methacrylate as the comonomer frameworks. In the reusability studies, the cryogel exhibited accumulating Cu(II) ions performance and excellent regeneration capability, making it a promising adsorbent for Cu(II) removal. [ABSTRACT FROM AUTHOR]

This research investigates the adsorption potential of pine cone powder (PCP) for the removal of copper ions (Cu(ii)) from aqueous solutions. The process of adsorption was reasonably fast, completed within a time of 60 min. The pseudo-second order kinetic model describes properly the Cu(ii) adsorption by PCP. The adsorbent was characterised by various instrumental techniques and batch experiments were conducted to investigate the effect of PCP dose, solution pH, particle size and initial Cu(ii) concentration on adsorption efficiency. Optimum Cu(ii) removal occurred at a slightly acidic pH, with a particle size less than 100 pm. The effective PCP dose was estimated to be 36 g L1. The increase in the initial concentration of Cu (II) was accompanied by a reduction in the rate of its reduction by almost half. The Langmuir model was the best fitting isotherm with a maximum adsorption capacity of 9.08 mg g-. The thermodynamic parameters values showed that the Cu(ii) adsorption was a spontaneous and endothermic process. The results of this research suggest that Cu(ii) could be removed through an environmentally friendly process using PCP as low-cost natural waste. [ABSTRACT FROM AUTHOR]

Heavy metal copper (Cu2+) ions contamination through the discharge of industrial effluent has caused serious environmental issues globally. As a result, the removal of Cu2+ ions from water bodies are of prime importance for human health and environmental protection. In the present study, the adsorption behaviour of zirconium (Zr)-based metal organic framework (MOF-801) prepared by solvothermal method in the removal of copper ion (Cu2+) from aqueous solution was studied. The results obtained from the batch mode adsorption studies revealed that at an initial Cu2+ concentration of 10 ​mg/L, contact time of 180 ​min and adsorbent dosage of 10 ​mg, the removal efficiency and equilibrium adsorption capacity of Cu2+ from the process were 97.80% and 9.78 ​mg/g, respectively. The influence of MOF-801 on the adsorption of Cu2+ ions was studied by Langmuir and Freundlich adsorption isotherm models. The graph was found to fit well with the Freundlich isotherm, and the MOF-801's maximal multilayer adsorption capacity was determined to be 16.58 ​mg/g. A kinetic study showed that Cu2+ removal was carried out in 180 ​min with a behaviour of pseudo-second-order kinetic model and in general, the majority of metal adsorption occurred within the first 30 ​min. After four cycles of adsorption-regeneration, a reusability test using adsorbent revealed a decline in adsorption removal effectiveness of less than 11%. The MOF-801 was shown to be effective in the removal of Cu2+ from wastewater treatment. [Display omitted] • Zr-based MOFs was successfully synthesized by one-pot solvothermal method for removing copper ions. • Pseudo-second-order kinetic model suitably described the kinetics of Cu adsorption. • The equilibrium data were fitted well with the Freundlich isotherm model. • Adsorption mechanism of Cu2+ ions on the Zr-based MOFs were investigated. • Adsorption efficiency by the Zr-based MOFs reached 89% after four cycles. [ABSTRACT FROM AUTHOR]