Synthesis of Prussian blue-embedded magnetic micro hydrogel for scavenging of cesium from aqueous solutions; Batch and dynamic investigations

Efficient selective removal of cesium using recyclable Prussian blue/luffa fiber: performance and phytotoxicity assessment insights

The treatment of radioactive wastewater has attracted extensive attention. Here, an adsorbent was designed to achieve efficient, stable, and recyclable removal of cesium ion contamination, and its adsorption properties were studied in detail. Prussian blue, a promising adsorbent for radioactive wastewater purification, has been often hindered in application due to its small size and easy agglomeration. To address this issue, the luffa fiber with a large specific surface area was employed to form networks loading Prussian blue particles and enhance adsorption capacity. In this paper, the recyclable Prussian blue/luffa was prepared by an in situ synthesis approach. Means such as XRD, SEM, EDS, FTIR, and XPS were applied to characterize its morphology and physicochemical properties. It exhibited outstanding selective removal efficiency for Cs+ ions and the ability to be rapidly separated from wastewater. The equilibrium and adsorption kinetics followed the Langmuir isotherm and pseudo-second-order model with a maximum adsorption capacity of 102.01 mg/g. Both pH and temperature had effects on the adsorption performance. The removal efficiency of Cs+ by Prussian blue/luffa still retained 71.2% after the 3-cycle test, and the possible mechanism was ion caging and ion exchange. In addition, the presence of co-existing ions only reduced the removal rate by less than 10.0%. Importantly, phytotoxicity assessment is urgently needed to address the adverse effects of applied nanoparticle composites on environmental and human safety. The phytotoxicity assessment was investigated, and the results indicated that the composite had no obvious biotoxicity. It is expected to be a highly potential material for disposing of radioactive wastewater. Future applications may extend to the treatment of various types of radioactive waste, providing a sustainable and effective solution to the field of nuclear waste management.

Solar driven enhanced adsorption of radioactive Cs+ and Sr2+ from nuclear wastewater by chitosan-based aerogel embedded with prussian blue analog

The rational use of solar energy to achieve photothermal conversion is an attractive strategy to promote the efficient removal of radioactive Cs+ and Sr2+ from nuclear wastewater. Herein, a photothermal adsorbent of composite aerogel with three-dimensional porous structure is fabricated by integrating prussian blue analogues (PBAs) and straw biochar into the chitosan (CS) and waste leather scrap hydrolysate (WLSH) aerogel matrix (CS/WLSH/C/PBAs). The local heating effect generated by CS/WLSH/C/PBAs aerogel induce to generate steam, accelerating the enrichment of Cs+ and Sr2+ in the solution, which increase their interaction with the CS/WLSH/C/PBAs and improves their adsorption rates and capacities. Under simulated sunlight, the adsorption equilibrium times for Cs+ and Sr2+ by CS/WLSH/C/PBAs are shortened from 5 h in the dark condition to 2 h, with maximum adsorption capacities of 156.0 and 95.1 mg/g for Cs+ and Sr2+, respectively. Meanwhile, the CS/WLSH/C/PBAs aerogel also exhibits excellent reusability. Notably, the Cs+ and Sr2+ still can be efficiently removed in simulated seawater. Encouragingly, the CS/WLSH/C/PBAs aerogel also exhibits excellent adsorption properties for dyes and oils. This work provides insights for the design of multifunctional and efficient composite adsorbents, and paving a promising way for enhancing the adsorption of Cs+ and Sr2+ through solar energy.

Evaluation of anion exchange resin for sorption of selenium (IV) from aqueous solutions

In this work, selenium (IV) ions were adsorbed from aqueous solutions by the strongly basic anion exchange resin Amberlite IRA-400. The morphology of the resin before and after Se(IV) sorption was investigated using different techniques such as energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). To determine the ideal sorption conditions, a batch approach was used to examine the variables affecting Se(IV) sorption performance, including pH, shaking time, adsorbent dosage, initial metal ion concentration, and temperature. The results showed the optimal parameters for the highest percentage of selenium (80.25%) at an initial concentration of 100.0 mg L-1, pH 3.0, the adsorbent dosage of 10.0 mg, and the shaking time of 60.0 min. According to the experimental findings, the sorption process was satisfactorily explained by the pseudo-second-order kinetic model. The maximum adsorption capacity at pH 3.0 was 18.52 mg g-1, and the adsorption rather well followed the Langmuir adsorption isotherm. Moreover, exothermic and spontaneous sorption reaction was the result of thermodynamic properties (negativity of both ΔG° and ΔH°). The adsorption phase's random distribution of the resin-solution interface is indicated by the positive value of ΔSo. Finally, the desorption study was performed using different concentrations of desorbing agents; HNO3, HCl, and sodium acetate. The results illustrated that the effective desorbing agent was 1.0 mol L-1 HNO3, with desorption efficiency reaching about 96.4%. Finally, the Amberlite IRA-400 demonstrated excellent adsorption-desorption behavior over five times, suggesting that the Amberlite IRA-400 could be an effective candidate for the sorption of Se(IV) from several metal ions that occur in fission products.

Cesium adsorption from an aqueous medium for environmental remediation: A comprehensive analysis of adsorbents, sources, factors, models, challenges, and opportunities

Considering the widespread and indispensable nature of nuclear energy for future power generation, there is a concurrent increase in the discharge of radioactive Cs into water streams. Recent studies have demonstrated that adsorption is crucial in removing Cs from wastewater for environmental remediation. However, the existing literature lacks comprehensive studies on various adsorption methods, the capacities or efficiencies of adsorbents, influencing factors, isotherm and kinetic models of the Cs adsorption process. A bibliometric and comprehensive analysis was conducted using 1179 publications from the Web of Science Core Collection spanning from 2014 to 2023. It reviews and summarizes current publication trends, active countries, adsorption methods, adsorption capacities or efficiencies of adsorbents, tested water sources, influencing factors, isotherm, and kinetic models of Cs adsorption. The selection of suitable adsorbents and operating parameters is identified as a crucial factor. Over the past decade, due to their notable capacity for Cs adsorption, considerable research has focused on novel adsorbents, such as Prussian blue, graphene oxide, hydrogel, and nanoadsorbents (NA). However, there remains a need for further development of application-oriented laboratory-scale experiments. Future research directions should encompass exploring adsorption mechanisms, developing new adsorbents or their combinations, practical applications of lab-scale studies, and recycling radioactive Cs from wastewater. Drawing upon this literature review, we present the most recent research patterns concerning adsorbents to remove Cs, outline potential avenues for future research, and delineate the obstacles hindering effective adsorption. This comprehensive bibliometric review provides valuable insights into prevalent research focal points and emerging trends, serving as a helpful resource for researchers and policymakers seeking to understand the dynamics of adsorbents for Cs removal from water.

Adsorption behavior of Mo(VI) from aqueous solutions using tungstate-modified magnetic nanoparticle

A new magnetic nanoparticle modified with sodium tungstate (Mnp-Si-W) was synthesized and employed for the sorption of molybdenum from aqueous solutions. The prepared nanoparticles (Mnp-Si-W) were characterized by different advanced techniques. Different parameters that influenced the adsorption percent of Mo(VI) were investigated using a batch process. Based on a systematic investigation of the adsorption isotherms and kinetics models, Mo(VI) adsorption follows the Langmuir model and pseudo-second-order kinetics. According to the Langmuir isotherm model, the Mnp-Si-W nanoparticles exhibited a maximum adsorption capacity of 182.03 mg g-1 for Mo(VI) at pH 2.0. The effect of competing ions showed that the prepared nanoparticles have a high selectivity for the sorption of molybdenum. Moreover, the effect of some interfering anions on Mo(VI) ion sorption is found in the following order: phosphate < sulfate < chromate. Finally, the nanoparticle (Mnp-Si-W) can be successfully reused five times.