Eco-friendly one-pot synthesis of Prussian blue-embedded magnetic hydrogel beads for the removal of cesium from water

Abstract

A simple one-step approach to fabricating Prussian blue-embedded magnetic hydrogel beads (PB-MHBs) was fabricated for the effective magnetic removal of radioactive cesium (137Cs) from water. Through the simple dropwise addition of a mixed aqueous solution of iron salts, commercial PB and polyvinyl alcohol (PVA) to an ammonium hydroxide (NH4OH) solution, the formation of hydrogel beads and the encapsulation of PB in beads were achieved in one pot through the gelation of PVA with in situ-formed iron oxide nanoparticles as the cross-linker. The obtained PB-MHBs, with 43.77 weight % of PB, were stable without releasing PB for up to 2 weeks and could be effectively separated from aqueous solutions by an external magnetic field, which is convenient for the large-scale treatment of Cs-contaminated water. Detailed Cs adsorption studies revealed that the adsorption isotherms and kinetics could be effectively described by the Langmuir isotherm model and the pseudo-second-order model, respectively. Most importantly, the PB-MHBs exhibited excellent selectivity for 137Cs in 137Cs-contaminated simulated groundwater (55 Bq/g) with a high removal efficiency (>99.5%), and the effective removal of 137Cs from real seawater by these PB-MHBs demonstrated the excellent potential of this material for practical application in the decontamination of 137Cs-contaminated seawater.

The Era of Nanomaterials: A Safe Solution or a Risk for Marine Environmental Pollution?

“…The latest progress in the treatment of Cs-contaminated seawater underline the role of the Prussian blue-embedded magnetic hydrogel beads (PBMHBs) as recoverable adsorbent [23]. PB presents a high selectivity for radioactive Cs, which confers to these beads a high efficiency in removing it from seawater.…”

“…To date, experimental studies established that ENMs can be employed to efficiently restore different marine environmental matrices [21][22][23], reducing the impact of toxic chemicals, thus, preserving marine biodiversity, ecosystem functioning and services. However, as such, they are applied as primary ENMs to the environment and the balance between benefits and risks associated with their use is still under debate [24,25].…”

Towards the Extraction of Radioactive Cesium-137 from Water via Graphene/CNT and Nanostructured Prussian Blue Hybrid Nanocomposites: A Review

“…However, graphene and CNT based PB nanocomposites can be regarded as monolayer adsorption considering that the active sites lie on the surface of CNT and graphene, implying that all three models, Langmuir, Freundlich and Tempkin are appropriate. These equilibrium models are seconded by kinetic models such as, the pseudo first order (PFO) and second order kinetic models (PSO), which define the adsorption rate limiting factors [70,78,81,82]. The Elovich kinetic model has also been applied to chitosan-CNT-PB composites in consideration of their elemental heterogeneity, as the solid surfaces under study are energetically heterogeneous also [74].…”

“…Even in the highest ionic strength seawater, the amount of Fe leaching ranged from 0.95% to 0.61% while in natural water, Fe leaching as low as 0.0026% was observed. In another study with PB embedded magnetic hydrogels, leaching of Fe was studied over a period of two weeks and only a 0.3% increase in Fe was observed in the solution [81]. Graphene is also considered a chemically stable material.…”

Foto-sorção de metais alcalinos utilizando a heterojunção de SiO>sub<2>/sub<//TiO>sub<2>/sub<//PB

“…Neste contexto, muitas são as tecnologias empregadas para o desenvolvimento de suportes adequados. Dentre elas, o uso de materiais nanoestruturados com alta área superficial, ou com propriedades magnéticas, como zeólitas, grafeno e magnetita têm sido aplicados na imobilização do PB para separação pós-adsorção e reciclagem[170][171][172][173][174]. Entretanto, a aplicação de materiais nanoestruturados baseados na heterojunção de TiO2/PB suportados em sílica para adsorção e foto-sorção de metais alcalinos não é muito difundida na literatura.Fotocatalisadores nanoestruturados baseados em TiO2 destacam-se como uma das tecnologias promissoras para remediação ambiental tanto de contaminação por compostos orgânicos quanto inorgânicos[175,176].…”