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Simultaneous removal of radiocobalt and manganese by adsorption onto polyacrylonitrile/hexadecyltrimethylammonium bromide/potassium copper hexacyanoferrate (PAN/HDTMA/KCuHCF) composite was studied. The synthesized composite was characterized by Fourier-transformed infrared (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The influence of the solution pH was studied in the range 1.5–7.8 and the results showed the effectiveness of the synthesized composite for simultaneous adsorption of radiocobalt and manganese in the pH range 2.5–6 at an adsorbent mass of 4 g/L. Adsorption kinetic data of manganese at the studied concentrations were best fitted by pseudo-second-order kinetic model and the diffusion study showed that the adsorption process was controlled by film diffusion. Thermodynamic parameters (ΔGo, ΔHo and ΔSo) were estimated and the results indicated that adsorption processes of the concerned (radio)toxicants were spontaneous and endothermic in nature. Of the studied isotherm models, Freundlich and Langmuir were the best ones for describing the adsorption isotherm data of radiocobalt and manganese, respectively. The adsorption capacity of PAN/HDTMA/KCuHCF was found to be 23.629 (for radiocobalt) and 62.854 (for manganese). Desorption of Radiocobalt and manganese loaded onto PAN/HDTMA/KCuHCF composite was studied using various desorbing agents at different concentrations.

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A mesoporous silicate material (MS) was effectively synthesized and applied as a solid sorbent for removal of radioactive Sr(II) ions from aqueous solution. MS was characterized using different tools including N2 adsorption-desorption analysis, FT-IR, XRD and SEM. The synthesized material has crystalline, porous nature and exhibited a large surface area of about 905.18 m2 g−1. The uptake of Sr(II) ions onto MS was investigated under different batch experimental conditions involving pH, equilibrium time, sample weight and initial concentration of Sr(II) ions. About 98 % of Sr(II) radionuclides were uptaken at pH 12 in the first minute. Different isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich and Temkin) were applied to analyze the obtained experimental sorption equilibrium data. The Langmuir isotherm model was aligned well with the sorption data. The maximum sorption capacity (Q max) of MS towards strontium ions attained the value 0.991 mmol/g. The parameters (ΔG°, ΔH° and ΔS°) were calculated from thermodynamic study and their values showed that sorption process of Sr(II) ions on MS is strong, take place spontaneously, and considered as endothermic process. The synthesized MS had the ability to efficiently remove Sr(II) radionuclides even in the presence of Na+ and Ca2+ as competing cations in aqueous solution. Among the studied desorbing agents, CaCl2 was the best one for desorbing Sr(II) radionuclides loaded onto MS. The synthesized MS was reused for sorption of strontium up to four cycles with acceptable efficiency.

Natural zeolite is organically modified with the surfactant cetyltrimethylammonium bromide (CTAB) and employed as a dual-function material for simultaneous adsorption of Cs+ cations and HCrO4− anions from aqueous solutions. Unmodified and modified zeolites are characterized by Fourier transform infrared (FTIR), dynamic light scattering (DLS), nitrogen adsorption–desorption isotherms, and X-ray diffraction (XRD). The results showed that CTAB-zeolite had the efficiency to simultaneously adsorb the concerned species in the pH range 2.5–4.2. The kinetic data showed that 90 and 300 min for Cs(I) and Cr(VI), respectively, were sufficient to attain equilibrium and the data are well-fitted by the double-exponential kinetic model. Of the studied adsorption isotherm models, Redlich-Peterson was the best one for describing the equilibrium adsorption isotherms. Values of ∆H°, ∆S°, and ∆G° for the present adsorption processes are estimated. CTAB-zeolite exhibited adsorption capacities of 0.713 and 1.216 mmol/g for Cs(I) and Cr(VI), respectively, which are comparable with the data reported in the literature. The adsorption mechanism of the concerned (radio)toxicants is proposed.