Removal and recovery of copper and nickel ions from aqueous solution by poly(methacrylamide-co-acrylic acid)/montmorillonite nanocomposites

Green synthesis and characterization of iron oxide nanoparticles for the removal of heavy metals (Cd2+ and Ni2+) from aqueous solutions with Antimicrobial Investigation

Clove and green Coffee (g-Coffee) extracts were used to synthesize green iron oxide nanoparticles, which were then used to sorb Cd²⁺ and Ni²⁺ ions out of an aqueous solution. Investigations with x-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, nitrogen adsorption and desorption (BET), Zeta potential, and scanning electron microscopy were performed to know and understand more about the chemical structure and surface morphology of the produced iron oxide nanoparticles. The characterization revealed that the main component of iron nanoparticles was magnetite when the Clove extract was used as a reducing agent for Fe³⁺, but both magnetite and hematite were included when the g-Coffee extract was used. Sorption capacity for metal ions was studied as a function of sorbent dosage, metal ion concentration, and sorption period. The maximum Cd²⁺ adsorption capacity was 78 and 74 mg/g, while that of Ni²⁺ was 64.8 and 80 mg/g for iron nanoparticles prepared using Clove and g-Coffee, respectively. Different isotherm and kinetic adsorption models were used to fit experimental adsorption data. Adsorption of Cd²⁺ and Ni²⁺ on the iron oxide surface was found to be heterogeneous, and the mechanism of chemisorption is involved in the stage of determining the rate. The correlation coefficient R² and error functions like RMSE, MES and MAE were used to evaluate the best fit models to the experimental adsorption data. The adsorption mechanism was explored using FTIR analysis. Antimicrobial study showed broad spectrum antibacterial activity of the tested nanomaterials against both Gram positive (S. aureus) (25923) and Gram negative (E. coli) (25913) bacteria with increased activity against Gram positive bacteria than Gram negative one and more activity for Green iron oxide nanoparticles prepared from Clove than g-Coffee one.

Enhanced adsorptive composite foams for copper (II) removal utilising bio-renewable polyisoprene-functionalised carbon derived from coconut shell waste

A bio -renewable polyisoprene obtained from Hevea Brasiliensis was used to produce functionalised carbon composite foam as an adsorbent for heavy metal ions. Functionalised carbon materials (C-SO₃H, C-COOH, or C-NH₂) derived from coconut shell waste were prepared via a hydrothermal treatment. Scanning electron microscopy images showed that the functionalised carbon particles had spherical shapes with rough surfaces. X-ray photoelectron spectroscopy confirmed that the functional groups were successfully functionalised over the carbon surface. The foaming process allowed for the addition of carbon (up to seven parts per hundred of rubber) to the high ammonia natural rubber latex. The composite foams had open pore structures with good dispersion of the functionalised carbon. The foam performance on copper ion adsorption has been investigated with regard to their functional group and adsorption conditions. The carbon foams achieved maximum Cu(II) adsorption at 56.5 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{mg g}}_{\text{foam}}^{-1}$$\end{document}mg gfoam-1 for C-SO₃H, 55.7 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{mg g}}_{\text{foam}}^{-1}$$\end{document}mg gfoam-1 for C-COOH, and 41.9 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{mg g}}_{\text{foam}}^{-1}$$\end{document}mg gfoam-1 for C-NH₂, and the adsorption behaviour followed a pseudo-second order kinetics model.

Facile Synthesis of Novel Carboxymethyl-Chitosan/Sodium Alginate Grafted with Amino-Carbamate Moiety/Bentonite Clay Composite for Effective Biosorption of Ni (II) from Aqueous Solution

In the present study, a novel biosorbent clay composite, based on carboxymethyl-chitosan/sodium alginate grafted with amino-carbamate moiety/bentonite clay (CA-CMC/Bt) was prepared. The produced sorbent was conditioned in the form of hydrogel beads by ionotropic gelation with Ca(II) ions, and thoroughly characterized using FTIR, XRF, XRD, SEM and zeta potential measurements. FTIR and SEM confirmed the successful grafting and intercalation of clay mineral into modified biopolymer. Hydrogel beads were observed to be very integrated and stable under a wide pH working range (from 2.0 to 12.0). CA-CMC/Bt was employed for adsorptive remediation of Ni(II) from aqueous media. Sorption process was found as a function of various parameters such as sorbent dosage, contact time, pH and initial concentration. Kinetic data could be well explained by pseudo second order rate equation (PSORE), suggesting that complexation or valence forces are playing significant role in the uptake of Ni(II) ions. Isothermal sorption data was analysed using different sorption models such as Langmuir, Freundlich and Sips. Data was well fitted with Langmuir and Sips model, maximum monolayer sorption capacity (qm) was calculated (by non-linear fitting of data) as 159 mg/g at 298 K and pH 5.5. Separation factor (RL) was found as 0 < RL < 1 which indicated favourable sorption. Thermodynamic parameters i.e. ΔGo, ΔHo and ΔSo were quantified and patterned the sorption process as exothermic, spontaneous with increase in system entropy. CA-CMC/Bt was found cost-effective, efficient and reusable material in Ni(II) competitive recovery.

Efficient removal of copper ions using a hydrogel bead triggered by the cationic hectorite clay and anionic sodium alginate

Sodium alginate (SA) is a linear biopolymer, which is the nontoxic, biodegradable, and rich in carboxyl and hydroxyl groups. In the paper, the SA-based hydrogel bead was prepared by the cationic hectorite clay and anionic sodium alginate with a simple ionic gelation method under freeze-drying, and the adsorption properties were evaluated by the removal of copper ions from aqueous solutions. The composites were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherm (BET), thermal analysis (TG), and Fourier transform infrared spectroscopy (FT-IR). The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data and the Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin models were applied to describe the adsorption isotherms. The results showed that the adsorption process was found to follow the Freundlich isotherm model and the maximum sorption capacity was observed to be 160.28 mg/g under the initial concentration from 10 to 700 mg/L at 45 °C. Adsorption kinetics data fitted well with pseudo-second-order rate model. The porous structure of the composite was responsible for the adsorption of Cu²⁺ ions. But the adsorption ability could be improved by pH. Finally, the adsorption mechanism was suggested. Graphical abstract.

Preparation of montmorillonite grafted polyacrylic acid composite and study on its adsorption properties of lanthanum ions from aqueous solution

Montmorillonite grafted polyacrylic acid composite (GNM) was prepared by using ultraviolet radiation grafting method in this work. The synthesized materials were characterized by XRF, SEM, FTIR, XRD, TG, and XPS. The experimental equilibrium data indicates that the adsorbent is suitable for the Langmuir model and belongs to the pseudo-second-order kinetic model. The entire adsorption process is spontaneous, endothermic, and chaotically enhanced by thermodynamic analysis. The maximum adsorption capacity of La(III) by GNM was 280.54 mg/g at 313.15 K. In addition, the regeneration experiment shows that the adsorbent has good reusability and stable desorption efficiency. This study demonstrates that GNM has high adsorption performance and La(III) adsorption and regeneration capabilities to solve the water pollution caused by rare earth ions and regeneration capabilities for La(III).

Effective removal of heavy metals by nanosized hydrous zirconia composite hydrogel and adsorption behavior study

A novel type of adsorbent, hydrous zirconium oxide (HZO) based on polymer hydrogel (HZO-P(TAA/HEA) hydrogel), was synthesized by irradiation polymerization and in situ precipitation methods to remove heavy metals from water efficiently. The composite hydrogel was characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), swelling kinetics, zeta potential, X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS). The results indicated that HZO nanoparticles were stably loaded on the P(TAA/HEA) hydrogel, swelling properties, and thermal stability were also enhanced after the loading of HZO. Besides, the batch adsorption experiments revealed that adsorption time, pH, initial concentration of heavy metals, and coexisting ions influenced the adsorption process significantly. The adsorption capacities of HZO-P(TAA/HEA) hydrogel for Pb²⁺, Cu²⁺, Cd²⁺, and Ni²⁺ was 0.620 mmol g^-1, 0.615 mmol g^-1, 0.701 mmol g^-1, and 0.700 mmol g^-1, respectively. The adsorption isotherms fitted Langmuir equation well, and the adsorption kinetics followed second-order kinetics; it was manifested that the priority of competitive adsorption followed the order: Pb²⁺ > Cu²⁺ > Ni²⁺ > Cd²⁺. Furthermore, based on the analysis results of FTIR and XPS, the adsorption mechanism could mainly be the complexation between hydrous zirconia and heavy metals. The results indicate that nanocomposite HZO-P(TAA/HEA) hydrogel is a promising heavy metal adsorbent.

Nano@lignocellulose intercalated montmorillonite as adsorbent for effective Mn(II) removal from aqueous solution

This paper describes the preparation of nano@lignocellulose (nano@LC) and a nano@lignocellulose/montmorillonite (nano@LC/MT) nanocomposite, as well as the capacity of the nano@LC/MT for adsorbing manganese ions from aqueous solution. The structure of nano@LC and nano@LC/MT was characterised by Fourier-transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy, and Transmission electron microscopy, which revealed that the diffraction peak of montmorillonite almost disappeared, infrared bands of the functional groups shifted, and morphology of the material changed after the formation of the composite. The optimum conditions for the adsorption of Mn(II) on the nano@LC/MT nanocomposite were investigated in detail by changing the initial Mn(II) concentration, pH, adsorption temperature, and time. The results revealed that the adsorption capacity of the nano@LC/MT nanocomposite for Mn(II) reached 628.0503 mg/g at a Mn(II) initial concentration of 900 mg/L, solution pH 5.8, adsorption temperature 55 °C, and adsorption time 160 min. Adsorption kinetics experiments revealed good agreement between the experimental data and the pseudo-second order kinetic model. The experimental data was satisfactorily fitted to the Langmuir isotherm. Adsorption-desorption results showed that nano@LC/MT exhibited excellent reusability. The adsorption mechanism was investigated through FT-IR and EDX spectroscopic analyses. The results suggested that nano@LC/MT have great potential in removing Mn(II) from water.

Characterization, preparation, and uses of nanomagnetic Fe3O4 impregnated onto fish scale as more efficient adsorbent for Cu2+ ion adsorption

In this research, the Cu²⁺ ion adsorption from aqueous solution was investigated by fish scale (FS) and nanomagnetic (Fe₃O₄) loaded fish scale (MFS) from fishery biomass. We characterized the structure and morphology of synthesized magnetic adsorbent by Fourier transform infrared spectroscopy (FTIR), FESEM, and XRD. The FTIR and XRD tests confirmed the collagen fibers, apatite crystals, and nanomagnetite particles presence in the MFS structure. The isotherm models of Langmuir, Freundlich, and Dubinin-Radushkevich were exerted to the empirical equilibrium data, by which was found that the Langmuir equation have the best fit to the experimental data in comparison to the other isotherm equations. The maximum capacities of monolayer coverage of FS and MFS for adsorption of Cu²⁺ ions were achieved, respectively, 61.73 and 103.1 mg g^-1 based on Langmuir isotherm at 45 °C. It was also discovered that the Cu²⁺ ion adsorption onto MFS was totally a physisorption-controlled process. It was perceived that the model of pseudo-second order rate kinetics also could be applied for predicting of studied adsorption processes. Here, the adsorption was a spontaneous and endothermic process because of the negative and the positive values of ∆G⁰ and ∆H⁰, respectively. The reusability potential of the used adsorbents was studied, so that the results showed an efficiency of 76.5 and 83.92% for FS and MFS, respectively, after four adsorption-desorption cycles.

Radioactive Cobalt(II) Removal from Aqueous Solutions Using a Reusable Nanocomposite: Kinetic, Isotherms, and Mechanistic Study

A lignocellulose/montmorillonite (LMT) nanocomposite was prepared as a reusable adsorbent for cobalt(II) ions, and characterized by nitrogen (N₂) adsorption/desorption isotherm, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). LMT exhibited efficient adsorption of cobalt ions (Co(II)), and the adsorbed Co(II) was readily desorbed by nitric acid (HNO₃). All parameters affecting the adsorption and/or desorption of Co(II), including initial Co(II) concentration, pH value, temperature, HNO₃ concentration, and time, were optimized. The kinetic data analysis showed that the adsorption followed the pseudo-second-order kinetic model and fit well into the Langmuir isotherm equation. Notably, the nanocomposite can be used four times without significantly losing adsorbent capability. The Energy-Dispersive X-ray (EDX) and FTIR spectra analysis also revealed that the adsorption mechanism may be mainly a chemical adsorption dominated process.

Adsorptive removal of nickel(II) ions from aqueous environment: A review

Among various methods adsorption can be efficiently employed for the treatment of heavy metal ions contaminated wastewater. In this context the authors reviewed variety of adsorbents used by various researchers for the removal of nickel(II) ions from aqueous environment. One of the objectives of this review article is to assemble the scattered available enlightenment on a wide range of potentially effective adsorbents for nickel(II) ions removal. This work critically assessed existing knowledge and research on the uptake of nickel by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites. The system's performance is evaluated with respect to the overall metal removal and the adsorption capacity. In addition, the equilibrium adsorption isotherms, kinetics and thermodynamics data as well as various optimal experimental conditions (solution pH, equilibrium contact time and dosage of adsorbent) of different adsorbents towards Ni(II) ions were also analyzed. It is evident from a literature survey of more than 190 published articles that agricultural solid waste materials, natural materials and biosorbents have demonstrated outstanding adsorption capabilities for Ni(II) ions.

Adsorption and desorption of nickel(II) ions from aqueous solution by a lignocellulose/montmorillonite nanocomposite

A new and inexpensive lignocellulose/montmorillonite (LNC/MMT) nanocomposite was prepared by a chemical intercalation of LNC into MMT and was subsequently investigated as an adsorbent in batch systems for the adsorption-desorption of Ni(II) ions in an aqueous solution. The optimum conditions for the Ni(II) ion adsorption capacity of the LNC/MMT nanocomposite were studied in detail by varying parameters such as the initial Ni(II) concentration, the solution pH value, the adsorption temperature and time. The results indicated that the maximum adsorption capacity of Ni(II) reached 94.86 mg/g at an initial Ni(II) concentration of 0.0032 mol/L, a solution pH of 6.8, an adsorption temperature of 70°C, and adsorption time of 40 min. The represented adsorption kinetics model exhibited good agreement between the experimental data and the pseudo-second-order kinetic model. The Langmuir isotherm equation best fit the experimental data. The structure of the LNC/MMT nanocomposite was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), whereas the adsorption mechanism was discussed in combination with the results obtained from scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy analyses (FTIR). The desorption capacity of the LNC/MMT nanocomposite depended on parameters such as HNO₃ concentration, desorption temperature, and desorption time. The satisfactory desorption capacity of 81.34 mg/g was obtained at a HNO₃ concentration, desorption temperature, and desorption time of 0.2 mol/L, 60 ºC, and 30 min, respectively. The regeneration studies showed that the adsorption capacity of the LNC/MMT nanocomposite was consistent for five cycles without any appreciable loss in the batch process and confirmed that the LNC/MMT nanocomposite was reusable. The overall study revealed that the LNC/MMT nanocomposite functioned as an effective adsorbent in the detoxification of Ni(II)-contaminated wastewater.

Selective removal of transition metal ions from aqueous solution by metal–organic frameworks

Carboxyl groups in adjacent ligands in UiO-66(Zr)–2COOH exhibit specific capture performance for Cu²⁺, resulting in high separation selectivity for Cu²⁺/Ni²⁺.