Enhanced Pollutant Adsorption and Regeneration of Layered Double Hydroxide-Based Photoregenerable Adsorbent

Abstract

Efforts to combine photocatalysts with organic and inorganic adsorbents in engineered composite materials have been pursued extensively to harness sunlight for a green, sustainable regeneration of exhausted adsorbent. Recent advances combining benchmark photocatalyst, titanium dioxide (TiO 2 ), with an inorganic adsorbent, layered double hydroxides (LDHs), have shown potential for an inorganic adsorbent−photocatalyst system but faced critical limitations in realizing practical applications: low adsorption capacity and slow, inefficient photocatalytic regeneration. This study presents an enhanced TiO 2 /LDH based material that demonstrates a dramatically increased efficiency for both decontamination through adsorption and subsequent solar, photocatalytic regeneration. The combination of delamination and high temperature treatment of LDH is utilized to drastically enhance the adsorption capacity toward model contaminant Methyl Orange to 1450−1459 mg/g, which is even higher than most commercial and lab-synthesized carbon-based adsorbents. Light-active plasmonic nanoparticles are employed to increase the photocatalytic regeneration performance, and experimental results show that the synthesized composite material regains above 97% of its adsorption capacity for 5 cycles of regeneration and readsorption. Overall, the results of this study demonstrate potential for the development of inorganic multifunctional adsorbents that can harness a variety of chemical reactions without the loss of adsorptivity over long-term use.

Insights into the Crucial Role of Electron and Spin Structures in Heteroatom-Doped Covalent Triazine Frameworks for Removing Organic Micropollutants

“…In recent years, extensive use of PPCPs in human activities has brought a water shortage crisis characterized by organic micropollutants (OMPs). , The processing method combining adsorption with photocatalysis is considered a promising solution. It is low-cost, nontoxic, and environmentally friendly in treating processes , and avoids mass transfer resistance due to low concentrations by preconcentration of adsorption. , However, currently developed photocatalysts lack strong adsorption properties, making it challenging to achieve high pollutant removal efficiency at low concentrations. , In addition, composites coupling adsorbents and photocatalysts would cause site competition between adsorbed and catalytic components, hindering the adsorption or photocatalysis reaction process. − Therefore, developing efficient and stable materials with adsorption/photocatalytic dual functions to achieve a sunlight-driven self-cleaning solution for OMP removal is a worthy frontier.…”

“…5,6 However, currently developed photocatalysts lack strong adsorption properties, making it challenging to achieve high pollutant removal efficiency at low concentrations. 7,8 In addition, composites coupling adsorbents and photocatalysts would cause site competition between adsorbed and catalytic components, hindering the adsorption or photocatalysis reaction process. 9−11 Therefore, developing efficient and stable materials with adsorption/photocatalytic dual functions to achieve a sunlight-driven self-cleaning solution for OMP removal is a worthy frontier.…”

Recent Advances on Porous Materials for Synergetic Adsorption and Photocatalysis

“…The regeneration of porous photocatalysts can be realized by the continuous photocatalytic degradation of the adsorbed pollutants, instead of resorting to any post-treatments, such as washing or applying heat and/or vacuum, necessary in the operation of conventional adsorption-based pollution abatement. [9][10][11] Photocatalysis is on the other hand a promising approach for generating energy via H 2 production (water splitting) and CO 2 reduction by using the photogenerated electrons in the conduction band of photocatalysts. [12][13][14][15] For both photocatalytic environmental and energy applications, porous photocatalysts generally outperform the non-porous counterparts.…”

Interfacial solar evaporation driven lead removal from a contaminated soil

“…Such a green and highly efficient water evaporation technology has been intensively applied in many fields including seawater desalination, wastewater purification, electricity generation and sterilization. [21][22][23][24][25][26][27][28][29][30][31][32][33] During interfacial solar evaporation-based seawater desalination, salt ions are transferred to the evaporation surfaces potentially causing salt crystallization and accumulation on the evaporation surface. [34][35][36] While this issue is detrimental for seawater desalination, it can be useful in other applications, especially when these specific ions are required to be removed, [37][38][39][40] This is reminiscent of traditional soil remediation technologies which require hazardous heavy metal ions to be extracted and removed from soil.…”