Surface-Encapsulated Bismuth Molybdate-Layered Silicate Hybrids as Sorbents for Photocatalytic Filtration Membranes

Abstract

Groundwater is being depleted globally at an average rate of more than one meter per year, during a period when more than a quarter of the human population has no access to potable water. Aside from overexploitation, freshwater security is also threatened by climate change and chemical pollution. The contamination of surface and groundwater by industrial substances is also undermining the vitality of ecosystems. It was previously shown that {100}-faceted Bi 2 MoO 6 − Laponite hybrids effectively bind and photodegrade molecular species, aiding in the decontamination of water. In this study, the encapsulation of Bi 2 MoO 6 −Laponite particles with the polymers butyl acrylate and styrene further enhanced adsorption of methylene blue by 31.4%, with a specific adsorption capacity of 192 μmol/g. The polymer−particle composites were deposited to form membranes and their efficacies in water filtration and photodegradation were examined. Among the different surface modifications examined, the highest dye sorption was obtained by butyl acrylate and styrene (3:2) with a 5 mol % cross-linker. This study provides a method for enhancing the molecular adsorption of composite particles used in membranes capable of multiple cycles of adsorption and photodegradation, advancing the application of such systems to water filtration.

Layered Double Hydroxide–Bismuth Molybdate Hybrids toward Water Remediation via Selective Adsorption of Anionic Species

“…Moreover, the photogenerated current in CAB-0.2x indicates that these particles can potentially be reused by photocatalytically degrading the adsorbed dye. Previous work has also established that the sorption performance can be further enhanced by encapsulation with a thin polymer shell . The choice of LDH, apart from improving the adsorption performance, can also influence the optical properties of the composite and heterojunction formation, which could further enhance photocatalytic performance.…”

“…Previous work has also established that the sorption performance can be further enhanced by encapsulation with a thin polymer shell. 56 The choice of LDH, apart from improving the adsorption performance, can also influence the optical properties of the composite and heterojunction formation, which could further enhance photocatalytic performance. Furthermore, ion leaching from the LDH may be responsible for defect formation in BMO, particularly O vacancies, as such leaching-induced defect formation has been previously observed in the growth of ZnIn 2 S 4 in Laponite.…”

Investigating Solvent-Induced Aggregation in Edge-Functionalized Layered Silicates via All-Atom Molecular Dynamics Simulations

“…These minerals are composed of a ∼1-nm thick tetrahedral–octahedral–tetrahedral-layered structure in which the basal surface obtains an anionic charge to balance the substitution of atoms in the octahedral layer (e.g., Mg for Al in the case of montmorillonite), whereas the Si-OH edge sites can be partially or fully protonated depending on the pH. − When exfoliated fully, the principal particle is highly anisotropic in both shape and surface charge, with significant cation exchange capacity at the basal surface which is normally balanced by Na + ions. Layered silicate clays have found numerous applications due to their unique properties, including biomedical applications in drug delivery and tissue engineering, − adsorption toward water remediation, − films with improved gas barrier properties and mechanical stability, − synthesis of semiconductor photocatalysts, − and other functional nanocomposites. − …”

Thin silica shell on Ag3PO4 nanoparticles augments stability and photocatalytic reusability

“…Semiconductor photocatalysts have the ability to degrade organic contaminants present in water using solar energy. [5][6][7][8][9][10][11][12] Semiconductors with a wide band gap, such as TiO 2 and ZnO, are widely utilised for the photodegradation of organic contaminants. However, their application is limited by their UV wavelength absorption.…”