The efficiency of 133Ba and 137Cs removal from aqueous solution is vital to mitigate ecological concerns over spreading these radionuclides in the environment. The present work focused on the use of ...Turkish perlite for the sorptive removal of 133Ba and 137Cs from aqueous solution by the radioindicator method. Perlite was characterized by XRF, XRD, FTIR, SEM–EDX, and BET analyses. The maximum percentage removals of 88.2% and 78.7% were obtained for 133Ba and 137Cs at pH 6 and pH 9, respectively. For both ions, the sorption equilibrium was attained relatively rapidly. Experimental kinetic data were well described with pseudo-second-order and intraparticle diffusion models. The uptake of both ions increased with the increase in metal concentration (1 × 10−5 to 5 × 10−2 mol/L) in solution. The maximum uptake capacities of 133Ba and 137Cs were found to be 1.96 and 2.11 mmol/g, respectively. The effect of competing ions decreased in the order of Ca2+>K+>Ni2+>Na+ for 133Ba sorption, whereas for 137Cs sorption, the order was determined as Ca2+>Ni2+>K+>Na+. Selectivity studies pointed out that sorption of 133Ba onto perlite is preferable to 137Cs. Therefore, Turkish perlite is a promising, cost-effective, and efficient natural material for the removal of 133Ba and 137Cs from relatively diluted aqueous solution.
Growing concern over the hazardous effect of radionuclides on the environment is driving research on mitigation and deposition strategies for radioactive waste management. Currently, there are many ...techniques used for radionuclides separation from the environment such as ion exchange, solvent extraction, chemical precipitation and adsorption. Adsorbents are the leading area of research and many useful materials are being discovered in this category of radionuclide ion separation. The adsorption technologies lack the ability of selective removal of metal ions from solution. This drawback is eliminated by the use of ion-imprinted polymers, these materials having targeted binding sites for specific ions in the media. In this review article, we present recently published literature about the use of ion-imprinted polymers for the adsorption of 10 important hazardous radionuclides-U, Th, Cs, Sr, Ce, Tc, La, Cr, Ni, Co-found in the nuclear fuel cycle.
The study summarizes the results of monitoring the properties of two types of sorbents, BC1 (biochar sample 1) and BC2a (biochar sample 2), prepared by pyrolysis of bamboo biomass (BC1) and as its ...composite with montmorillonite K10 (BC2a). The main goal was to study their applicability to the Tc (VII) separation from liquid wastes, using NH4ReO4 as a carrier. The research was focused on determining the sorbents surface properties (by XRF (X-ray fluorescence) method and potentiometric titration in order to determine the properties of surface groups—Chemical Equilibrium Model (CEM) and Ion Exchange Model (IExM) models were applied here). As well as monitoring Tc (VII) (+Re(VII)) sorption, especially to determine equilibrium isotherm, the influence of pH and kinetics. The subject of research was also the dynamics of sorption, including its mathematical–physical modeling. Both sorbents have good properties against Tc (VII), however BC2a, due to the presence of montmorillonite, is more advantageous in this respect. It has a higher sorption capacity and faster kinetic investigation. An important finding is that the optimal pH is 2–3, which is related not only to the protonation of surface groups (they have a positive charge), but also to the negative form of the existence of Tc (VII) and Re (VII): TcO4− and ReO4−.
The aim of the presented study was to determine the influence of non-linear character of Cs sorption isotherm and dominant interlayer cation on the sorption and diffusion properties of the Czech ...compacted bentonite. Planar source and through diffusion experiments with Cs on the compacted bentonite were performed and evaluated by suitable methods accounting for the transient state of diffusion and the presence of separating filters. It was shown that the observed Cs concentration profiles can be appropriately simulated with the use of Langmuir isotherm. The fitted values of sorption parameters obtained from the evaluation of through diffusion experiments generally agreed with the values expected from the batch sorption experiments. The most important factor for the Cs diffusion was its total concentration in the experiment with Da values ranging from about 1⨯10−13 m2·s−1 at the Cs concentration 10−7 M to about 4⨯10−12 m2·s−1 at the Cs concentration 10−3 M. The observed discrepancies between the experimental data and the standard model based on Fickian diffusion were explained by the application of dual transport model using so-called surface diffusion theory. The importance of surface diffusion in through diffusion experiments increased with increasing Cs total concentration, which indicates that this effect is probably connected to the ion exchange mechanism on layer sites of bentonite.
•Diffusion experiments with Cs on Czech compacted bentonite were evaluated at transient state.•Langmuir isotherm was used upon the evaluation of diffusion experiments at lower Cs concentrations.•Linear isotherm and dual transport model were used at higher Cs concentrations.•Evaluation method of diffusion experiments with non-standard description was proposed.
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•Bamboo based biochar/montmorillonite composite preparation.•Porous biochar acted as support to host particles of montmorillonite.•The composite exhibited much better compared to raw ...biochar via nitrates removal.
Biochar is a promising immobilization tool for various contaminants in liquid wastes, aqueous solutions and soils. To further improve the sorption characteristics, a biochar/montmorillonite composite was produced and synthesized in an experimental pyrolysis reactor, using bamboo as biomass feedstock. The composite was characterized by physico-chemical and structural methods (FTIR, SEM, SEM/EDX, SSA, Low temperature nitrogen adsorption method). Based on these methods, the successful preparation of a bamboo based biochar/montmorillonite composite preparation has been demonstrated. The particles of montmorillonite were distributed across the biochar surface. The adsorption studies for removal nitrates from aqueous solutions were investigated by a batch method at laboratory temperatures. The experimental data were fitted by three adsorption models (Langmuir, Freundlich and DR; R2 > 0.93). The maximum adsorption capacity achieved by biochar at pH 4, was about 5 mg g−1 and by biochar/montmorillonite composite 9 mg g−1. The results suggest that the bamboo-based biochar/montmorillonite composite can be used effectively in the treatment of industrial effluents or waste water containing anionic pollutants such as nitrates.
In this work, highly crystalline CdS nanorods (NRs) were successfully synthesized by a facile, one-step solvothermal method. The as-prepared CdS NRs powder was characterized by XRD, FESEM, Raman, PL, ...XPS, BET, and UV-visible techniques to evaluate the structural, morphological, and optical properties. The photocatalytic performance of the as-synthesized CdS NRs was investigated for the photodegradation of RhB dye under visible light irradiations. It has been found that CdS NRs show maximum RhB degradation efficiency of 88.4% in 120 min. The excellent photodegradation ability of the CdS NRs can be attributed to their rod-like structure together with their large surface area and surface state. The kinetic study indicated that the photodegradation process was best described by the pseudo-first-order kinetic model. The possible mechanism for the photodegradation of RhB dye over CdS NRs was proposed in this paper.
The study investigated the adsorption behaviour of different activated carbon samples for pertechnetate under diverse conditions. Characterizations of A-CF-F and A-CF-Z samples were done using BET, ...FTIR, XRD, XRF and SEM–EDX methods. In batch experiments, maximum adsorption occured at pH 2, with a swift process and an optimal phase mixing time determined as 1 h for all of the samples. Analyzing experimental data using Langmuir and Freundlich adsorption models revealed coefficients of determination R
2
exceeding 90%. The Freundlich isotherm was found to be more suitable for describing the adsorption process.
This study focuses on the usage of chitosan/hydroxyapatite composites for pertechnetate removal from aqueous solutions. Pertechnetate, a prominent radionuclide in nuclear waste, presents ...environmental hazards due to its long half-life and mobility. The composites, formed by intergrating hydroxyapatite into chitosan matrices, demonstrate in situ nanohydroxyapatite generation. Investigation of the adsorption process involves assessing parameters like pH, contact time, and the influence of competetive ions. This research provides valuable insights for using composites to mitigate pertechnetate contamination.
133
Ba is a hazardous radionuclide generated during the operation of nuclear power plants.
133
Ba needs to be removed from waste solutions because its half-life (10.55 years) and gamma energy pose a ...significant threat to human health. Cigarette butt (CB) is a waste that causes serious environmental problems. Various types of adsorbent materials are prepared based on the cellulose in its structure. The focus of the present study is to synthesize a novel composite material derived from CBs and to investigate its
133
Ba removal capability. Microfibrillated cellulose (MFC) obtained from CBs was modified with hydroxyapatite (HAp) via the co‐precipitation method and converted into a composite adsorbent for the removal of
133
Ba ions. Response surface methodology (RSM) based on Box‐Behnken Design (BBD) was employed for the examination of process variables such as initial pH, metal concentration, and adsorbent amount on
133
Ba sorption. XRD and FTIR data confirmed the successful isolation of cellulose and the modification of the cellulose surface with HAp. The model F-value (100.04) and R
2
(0.99) suggested that the proposed model was significant. Optimum conditions were determined as initial pH of 8, contact time of 134 min, and concentration of 0.01 mol/L, and the barium sorption capacity of MFC‐HAp was found to be 0.75 mmol/g under these conditions. The maximum monolayer barium sorption capacity was determined to be 2.92 mmol/g. Combining cellulose and HAp to be a novel composite adsorbent is useful for reusing CB waste and promising for removing
133
Ba ions from aqueous solutions.
The work deals with the evaluation of biochar samples prepared from Phyllostachys Viridiglaucescens bamboo. This evaluation consists of the characterization of prepared materials' structural ...properties, batch and dynamic sorption experiments, and potentiometric titrations. The batch technique was focused on obtaining basic sorption data of ⁸⁸ᵐTcO₄⁻ on biochar samples including influence of pH, contact time, and Freundlich isotherm. ReO
, which has very similar chemical properties to ⁸⁸ᵐTcO₄⁻, was used as a carrier in the experiments. Theoretical modeling of titration curves of biochar samples was based on the application of surface complexation models, namely, so called Chemical Equilibrium Model (CEM) and Ion Exchange Model (IExM). In this case it is assumed that there are two types of surface groups, namely, the so-called layer and edge sites. The dynamic experimental data of sorption curves were fitted by a model based on complementary error function erfc(x).
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