Kinetic studies of Ni(II) ions adsorption from aqueous solutions using the blast furnace slag (BF slag)

In this work, we used the blast furnace slag for the nickel adsorption in aqueous solution. The physico-chemical characterization showed that the BF slag consists mainly of the silica, lime, and alumina. The specific surface area of the BF slag grains is of the order of 275.8 m2/g. The optimum elimination parameters are the agitation speed 200 rpm, pH 4.5, the adsorption temperature 20 °C, and particle size between 200 and 500 μm. The adsorption capacity and the efficiency of nickel removal by the BF slag after 90 min of agitation are respectively 53.58 mg/g and 92.7%.The experimental adsorption data showed that the pseudo-second-order model was the most appropriate in nickel adsorption kinetics; the adsorption isotherm could be described well by the Langmuir model indicating that the process was monolayer, and intra-particle diffusion is not the sole mechanism involved in this process. Thermodynamic study showed that the Ni(II) elimination by BF slag process is spontaneous, exothermic, and less entropic.

Surface Functionalized Halloysite with N-[3-(Trimethoxysilyl)Propyl] Ethylenediamine for Chromium and Nickel Adsorption from Aqueous Solution

In this study, -[3-(trimethoxysilyl)propyl] ethylenediamine - modified Indonesian natural halloysite was applied for Cr(III) and Ni(II) adsorption from aqueous solution. The studies include the physicochemical characterization of the synthesized material by using XRD, SEM, gas sorption analyzer, and FTIR analyses. Furthermore, the adsorption experiments were performed at a batch system for investigating the adsorption kinetics and thermodynamic. The results showed no significant changes in either the material crystallinity or specific surface area, but the changes of surface functional groups identified the anchored ammine modifier. Kinetic modeling showed pseudo-second-order model best fitted the experimental data for both adsorbents. Moreover, the thermodynamic studies represented the chemisorption interaction of modified halloysite with the adsorbate since the average adsorption enthalpy values are at 44.3 kJ/mol and 41.70 kJ/mol for Cr(III) and Ni(II), respectively.

Correlations between physico-chemical properties and nickel adsorption parameters in soils used in sanitary landfill liners

The adsorption of heavy metals by sanitary landfill liners represents a measure of protection of surface and groundwaters against contamination by metals, mitigating risks to public health. Hence, this research aimed to identify, from correlations, the influence of physico-chemical properties of soils applied in landfill liners using nickel adsorption parameters. Batch equilibrium tests with initial nickel concentrations of 45 to 1440 mg.L-1 were performed in clayey sand and bentonite clay soil, as well as in mixtures. Nickel adsorption parameters from Freundlich and Langmuir isotherm models were obtained, exhibiting a better adjustment in the Freundlich model based on R² and RMSE criteria. Thus, the addition of bentonite clay improved the adsorption to nickel, and the cationic exchange capacity (CEC) was the property that considerably influenced the metal retention in the studied soils.

Nickel ion removal from aqueous solutions through the adsorption process: a review

Recently, removal of nickel ions has been gaining a lot of attention because of the negative impact of nickel ions on the environment. The aim of this review paper is to organize the scattered available information on removal of nickel ions from aqueous solutions through the adsorption process. Survey on investigated materials suggests that composite- and polymer-based adsorbents have the most effective capability for nickel adsorption. The composite material class, i.e. CaCO3-maltose, followed by biopolymer-based material showed the highest Ni(II) adsorption capacity of 769.23 and 500 mg/g, respectively. The importance of treatment parameters (i.e. pH, temperature, contact time, and metal ion concentration) is discussed, together with their effect on the underlying physicochemical phenomena, giving particular attention to the adsorption/desorption mechanism. It was ascertained that adsorption of nickel ions is pH dependent and the optimal pH range for adsorption of Ni(II) ions was in range of 6–8. In general, nickel adsorption is an endothermic and spontaneous process that mainly occurs by forming a monolayer on the adsorbent (experimental data are often fitted by Langmuir isotherms and pseudo-second-order kinetics). Regeneration (i.e. desorption) is also reviewed, suggesting that acidic eluents (e.g. HCl and HNO3) allow, in most of the cases, an efficacious spent adsorbent recovery. The percentage use of desorption agents followed the order of acids (77%) > chelators (8.5%) > alkalis (8%) > salts (4.5%) > water (2%). Helpful information about adsorption and desorption of nickel ions from aqueous solutions is provided.