Application of Fe3O4/graphene oxide composite for the separation of Cs(I) and Sr(II) from aqueous solution

Decontamination of 137Cs,95Zr, 154Eu and 144Ce from aqueous solutions using polyacrylamide titanium tungstosilicate

Polyacrylamide titanium tungstosilicate (PAM/TiWSi) composite was synthesised using a sol–gel process and characterized via FT-IR, SEM, XRD, and TGA methods. The effects of several factors on the adsorption of Cs+, Eu3+, Ce3+and Zr4+ have been studied, including contact duration, pH, temperature, and starting concentration. PAM/TiWSi sorption of Cs+, Eu3+, Ce3+and Zr4+ was studied in terms of isotherms and kinetics. The Freundlich model was better linked with isotherm data than the Langmuir model. Cs+, Eu3+, Ce3+and Zr4+ have maximum sorption capacities (Qmax) of 30.7, 26.6, 25,3 and 29.7 mg.g−1, respectively. Furthermore, the sorption process was found based on pseudo-second-order.

Electro-assisted adsorption of Cs(I) and Co(II) from aqueous solution by capacitive deionization with activated carbon cloth/graphene oxide composite electrode

In this study, a new composite of activated carbon cloth/graphene oxide (ACC/GO) was prepared, characterized and used as electrode material for the electro-assisted adsorptive removal of Co²⁺ and Cs⁺ from aqueous solution. The ACC/GO composite was synthesized by a vacuum filtration method, and characterized by cyclic voltammetry and various surface characterization methods. Effect of applied voltage and initial concentration of Co²⁺ and Cs⁺ on their removal efficiency was examined. The kinetics and isotherms of Co²⁺ and Cs⁺ adsorption were investigated to explain the adsorption mechanism. At 0 V, the removal efficiency of Co²⁺ and Cs⁺ was 10.1% and 21.4%; at 1.2 V, electro-assistance increased the removal efficiency of Co²⁺ and Cs⁺ to 40.8% and 39.7%, respectively. Moreover, ACC/GO composite electrode had higher adsorption capacity compared to the pristine ACC electrode, due to its higher specific surface area and more oxygen-containing functional groups. The maximum adsorption capacity of Co²⁺ and Cs⁺ was 16.7 mg g^-1 and 22.9 mg g^-1, respectively at 1.2 V and 20 mg L^-1 by ACC/GO composite electrode. The modeling and experimental results demonstrated that the removal mechanism involved in physical adsorption, chemical adsorption, and electro-adsorption. Overall, the prepared ACC/GO composite electrode had high capacitive deionization performance in removing heavy metal ions from wastewater.

The adsorption of Cs+ from wastewater using lithium-modified montmorillonite caged in calcium alginate beads

The increasing nuclear energy consumption has posed serious environmental concerns (e.g. nuclear leakage), and the removal of radionuclides such as cesium becomes an urgent issue to be solved currently. In this research, a novel non-toxic adsorbent lithium-modified montmorillonite clay encapsulated in calcium alginate microbeads (MCA/Li) was fabricated by using ion-exchange method and then used successfully in the remediation of cesium-contaminated wastewater. Analyses of scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the physicochemical properties of adsorbent MCA/Li, such as internal crystal structure, constituent elements, and functional groups. The effects of concentration ratios (sodium alginate/montmorillonite), solution pH, contacting time and initial Cs⁺ concentration on the adsorption behavior were carefully investigated via batch adsorption experiments. The adsorbent MCA/Li exhibited higher selectivity and removal efficiency towards Cs⁺ with the maximum adsorption capacity of 100.25 mg/g. In the kinetics study, the pseudo-first-order fitted the cesium adsorption data of MCA/Li better than the pseudo-second-order. The adsorption mechanism studies revealed the process followed the Langmuir isotherm model, which suggested that Cs⁺ adsorption onto MCA/Li is a monolayer homogeneous adsorption process. The research findings indicated this novel adsorbent MCA/Li demonstrated great potential in radioactive wastewater treatment due to its convenience in synthesis, high adsorption capacity, and low cost.

Magnetite-based adsorbents for sequestration of radionuclides: a review

As a result of extensive research efforts by several research groups, magnetite-based materials have gained enormous attention in diverse fields including biomedicine, catalysis, energy and data storage devices, magnetic resonance imaging, and environmental remediation. Owing to their low production cost, ease of modification, biocompatibility, and superparamagnetism, the use of these materials for the abatement of environmental toxicants has been increasing continuously. Here we focus on the recent advances in the use of magnetite-based adsorbents for removal of radionuclides (such as 137Cs(i), 155Eu(iii), 90Sr(ii), 238U(vi), etc.) from diverse aqueous phases. This review summarizes the preparation and surface modification of magnetite-based adsorbents, their physicochemical properties, adsorption behavior and mechanism, and diverse conventional and recent environmental technological options for the treatment of water contaminated with radionuclides. In addition, case studies for the removal of radionuclides from actual contaminated sites are discussed, and finally the optimization of magnetite-based remedial solutions is presented for practical application.

Remediation of radiocesium-contaminated liquid waste, soil, and ash: a mini review since the Fukushima Daiichi Nuclear Power Plant accident

The radiation contamination after the Fukushima Daiichi Nuclear Power Plant accident attracts considerable concern all over the world. Many countries, areas, and oceans are greatly affected by the emergency situation other than Japan. An effective remediation strategy is in a highly urgent demand. Though plenty of works have been carried out, progressive achievements have not yet been well summarized. Here, we review the recent advances on the remediation of radiocesium-contaminated liquid waste, soil, and ash. The overview of the radiation contamination is firstly given. Afterwards, the current remediation strategies are critically reviewed in terms of the environmental medium. Special attentions are paid on the adsorption/ion exchange and electrically switched ion exchange methods. Finally, the present review outlines the possible works to do for the large-scale application of the novel remediation strategies.