Recovery Of Lead Ions Research Articles

Sorption properties of an amorphous hydroxo titanate towards Pb2+, Ni2+, and Cu2+ ions in aqueous solution

ABSTRACTTitanates may be selectively used as inorganic adsorbents for heavy metal ions owing to their stability and fast adsorption kinetics. Nevertheless, the synthesis of such materials usually requires extreme reaction conditions. In this work, a new titanium-based material was rapidly synthesized under mild laboratory conditions. The obtained amorphous hydroxo titanate was tested for heavy metal sorption through kinetic and equilibrium batch tests, which indicated that the new material had high adsorption rates and adsorption capacities towards Cu2+, Ni2+ and Pb2 ions. Adsorption kinetics were pseudo-second order, and equilibrium data fitted the Langmuir isotherm model. The calculated maximum adsorption capacities of Cu2+, Ni2+ and Pb2+ in deionized water were around 1 mmol g−1, and they decreased for Cu2+ and Ni2+ in the presence of Na+, Ca2+ and Mg2+ ions, whereas the alkali metal ions did not influence Pb2+ uptake. The efficiency of adsorption and recovery of lead ions were evaluated through column dynamic tests, by feeding the column with groundwater and tap water spiked with Pb2+. The high performance of the hydroxo titanate over several cycles of retention and elution suggested that the product is potentially useful for the solid phase extraction of lead at trace levels in natural water samples, with potential use in metal pre-concentration for analytical applications.

Functionalized silica nanoparticles for trapping Pb2+ ions via diazo‐azomethine scaffolds

Diazo‐azomethine coated silica sorbent for the adsorption of Pb2+ ions has been fabricated. The sorbent was obtained by one‐pot synthesis of silica nanoparticles in the presence of diazo‐azomethine molecules possessing silatranyl side chains for grafting via covalent bond formation. The functionalized silica nanoparticles exhibited characteristic physicochemical properties of diazo‐azomethine scaffolds as determined using Fourier transform infrared spectroscopy, scanning and transmission electron microscopies and thermogravimetric analysis. Various adsorption parameters such as pH, weight of adsorbent, time taken for equilibration and recovery of lead ions were optimized using a batch method. The sorbent showed high adsorption capacity for lead ions of 460.4 mg g−1 at pH = 4. The effect of various competing ions on the adsorption of lead ions was studied and interference was removed by using a masking agent. The sorbent can be regenerated and reused, and is compatible for the adsorption of Pb2+ ions from green leafy vegetables. Copyright © 2016 John Wiley & Sons, Ltd.

Graft copolymerization of cellulose acetate for removal and recovery of lead ions from wastewater

In this study, cellulose acetate (CA) was modified by grafting with an equimolar binary mixture of acrylic acid (AA) and acrylamide (AAm) via radical polymerization technique using benzoyl peroxide as an initiator. Comparative studies between CA powder and modified CA [CA-g-(AA-co-AAm)] were investigated for Pb(II) ions removal and recovery from wastewater. The main operating conditions such as pH, concentration of Pb(II) ions and sorbent dose were also studied. Kinetic modeling has been studied and lead uptake capacity was calculated using the Langmuir, Freundlich and Dubinin–Kaganer–Radushkevich (DKR) models. The maximum sorption capacity (qemax) for Pb ions was only 9.4mg/g for unmodified CA, while, it was reached to 66.67mg/g by using modified CA. Spectroscopic analysis (FTIR), SEM, EDX and XRD analysis were investigated for CA and modified CA before and after recovery of lead ions from wastewater.

Utilization of facile synthesized Fe3O4 nanoparticles as a selective support for preconcentration of lead ions from food and environmental samples

In this research, magnetic Fe3O4 nanoparticles were synthesized by a simple reaction system that takes 5 min at room temperature utilizing FeSO4 as the only iron source. Then their surface was modified with (3-aminopropyl)triethoxysilane and 4-bromo-3-(thiazol-2-ylimino)methylphenol using the Mannich reaction. Modified sorbent showed high selectivity for lead ions in the pH range of 6.5–8.0 as the relative selectivity factor (αr) of lead with respect to other cations was in the range of 150–1500. Fourier transform infrared, scanning electron microscopy, X-ray powder diffraction, vibrating sample magnetometry and elemental analysis techniques have been used for characterization of the prepared sorbent. The reusability of the sorbent was also investigated, and it was found that this sorbent is stable for up to eight adsorption–elution cycles without any noticeable drop-off in the recovery of lead ions.

Uptake and Recovery of Lead by Agarose Gel Polymers

Problem statement: The uptake and recovery of lead ions were investigated by using agarose gel polymers. Approach: The experimental results showed that the agarose gel were effective in removing Pb (II) from solution. Biosorption equilibrium was approached within 4 h. Pseudo second-order was applicable to all the sorption data over the entire time range. Results: The sorption data conformed well to both the Langmuir and the Freundlich isotherm model. The maximum adsorption capacity (qmax) onto agarose gel was 115 mg g-1 for Pb (II). The maximum uptake of metal ions was obtained at pH 2.0. At temperature 35°C, the biosorption of metal ions was found to be highest, with increase or decrease in temperature resulted in a decrease in the metal ions uptake capacity. Conclusion: Elution experiments were carried out to remove Pb (II) ions from loaded agarose gel and the bound metal ions could be eluted successfully using 0.1 M EDTA solution. The results suggest that agarose gel can be used as a biosorbent for an efficient removal of Pb(II) ions from aqueous solution.

Chromatographic separations and recovery of lead ions from a synthetic binary mixtures of some heavy metal using cation exchange resin

A simple solid phase extraction procedure on cation exchange resin Purolite C100 is presented. The procedure based on a column technique for separation and recovery of lead ions from synthetic binary mixtures. Equilibrium distribution coefficient, k d for the different metal ions such as Al(III), Fe(III), Ba(II) and Pb(II) in the presence of nitric acid and ammonium acetate solutions of variable concentrations was determined at 25 °C. The values of separation factor, α were evaluated. Quantitative separation of lead ions from a synthetic binary mixtures are based on the fact that ammonium acetate is a good elute for lead ions but fails to elute the other cations.