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In this study, a metal-phosphate layered/activated carbon (KMSP@AC) composed of potassium (K), manganese (Mn), tin (Sn) and phosphorous (P) was prepared by the solvothermal method. The proposed nanocomposite was used as an effective adsorbent to remove Cd(II), Co(II), Ni(II), Pb(II) and V(III) from water samples in oil-rich areas prior to ICP-OES analysis. The KMSP@AC was fully characterized using FTIR, SEM and EDX. Factors influencing the removal process (pH, adsorbent dosage, initial concentration and contact time) were studied and optimized. The experimental process was evaluated with kinetic and isotherm models. The adsorption isotherm investigation showed that the adsorption followed the monolayer Langmuir isotherm model with the maximum adsorption capacities of 25 mg/g (Cd 2+), 31 mg/g (Co 2+), 49 mg/g (Ni 3+), 91 mg/g (Pb 2+) and 141 mg/g (V 3+). The kinetic studies indicated that the pseudo-second-order model is well-fitted to the process with an appropriate correlation coefficient (R 2 > 0.99) at an equilibrium time of 120 min. The adsorption of metal ions on the surface of the adsorbent was mainly a physisorption process through electrostatic interactions.

In the present study, a new nanocomposite of iron/cobalt oxides and magnetic nanoparticle doped with polyaniline (PANI-Co3O4@MNPs) was synthesized and subsequently, evaluated for its potential in decontaminating nitrate ions from underground water. Various parameters such as pH, mass dosage, adsorption time, initial concentration and temperature important in obtaining optimum conditions required to attain maximum performance for the reported nanocomposite in nitrate removal were experimentally investigated. The important surface and chemical properties of PANI-Co3O4@MNPs including surface morphology and roughness, composition and chemical structure were evaluated using various spectroscopic techniques such as Field Emission Scanning Electron Microscope (FE-SEM), Energy-Dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared (FTIR). Finally, the removal of nitrate was assessed using kinetic, adsorption isotherm and thermodynamic studies to investigate the underlying mechanism of the removal process into PANI-Co3O4@MNPs sorbent. The kinetic studies and the adsorption isotherms have been well explained using pseudo first and the Freundlich models respectively whereas the thermodynamic parameters have been described in terms of enthalpy, entropy and Gibbs free energy which showed a negative value signifying that the adsorption process was exothermic and spontaneous in nature.

In this study, a novel nanocomposite adsorbent based on magnetic polyaniline and strontium-titanium (MP-SrTiO) nanoparticles was synthesized via a simple and low-cost polymerization method for efficiently removing of arsenic(III) ions from aqueous samples. The chemical structure, surface properties, and morphology of the prepared adsorbent were studied using Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). The main effective parameters on the removal efficiency, such as pH, adsorbent dosage, salt, and contact time, were studied and optimized. The validity of the proposed method was checked by adsorption isotherm and kinetics models. Consequently, the adsorption kinetics corresponded to the first order (R > 0.99), and the experimental equilibrium fitted the Langmuir model with a maximum monolayer adsorption capacity of 67.11 mg/g (R > 0.99) for arsenic(III) ions. Corresponding to thermodynamic Vant's Hof model (ΔG° (kJ/mol), ΔH° (kJ/mol), and ΔS° (kJ/mol K) - 8.19, - 60.61, and - 0.17, respectively), the mechanism and adsorption nature were investigated with that suggested exothermic and physisorption mechanism.

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