Photocatalytic foams for water treatment: A systematic review and meta-analysis

Photocatalysis has proven to be highly effective for the removal of recalcitrant organic micropollutants at the lab scale. However, drawbacks such as the need for downstream removal of nanoparticle slurries and low surface areas of immobilised catalyst have, so far, hindered large-scale application. Photocatalytic foams have the potential to address these issues and advance the field towards large scale deployment. This review offers the first comprehensive overview of the state-of-the-art in this growing research field while simultaneously addressing two key issues which are slowing down further progress: The lack of classification nomenclature for foams, particularly regarding pore size and production method, and the use of kinetics as the defining feature of a photocatalyst, when alternate figures of merit, such electrical and quantum efficiencies, may be more appropriate. These were particular evident from a semi-quantitative comparison of the literature reported here, which highlighted the need for standardisation of experimental methods within the field. Finally future perspectives and best practices are discussed and recommended

Sintese e aplicação de filmes biocomponentes nanoestruturados de 'TI'/'TI''O IND.2'/'W''O IND.3' por template e 'SI'/'TI''O IND.2'/'PT' por heterojunção em conversão de energia solar e remediação ambiental

The present project meets the challenge of exploring the use of photoelectrochemical devices based on Ti/TiO2/WO3 bicomponent nanostructured semiconductors prepared by templates and Si/TiO2/Pt prepared by microgrid heterojunction. The synthesis was performed by anodization and electrochemical deposition and the presence of anatese TiO2 and monoclinic WO3 was confirmed by X ray and EDS analysis. Difuse reflectance spectroscopy (DRS) analysis indicated Ti/TiO2/WO3 extension of optical absorption spectrum into the visible light region (red shift). Electrochemical characterisation was performed by linear sweep voltammetry under UV and visible light irradiation by two different lamp sources: 125 W high pressure mercury lamp and 150 W xenon lamp coupled to filters which isolte UV and visible light contribuition. Enhanced photocurrent response was obtained under high pressure mercury lamp 11,0 mA cm-2 and under xenon lamp irradiation the observed values are close to 0,4 mA cm-2. The Ti/TiO2/WO3 were used as photoanodes on the Reactive Black 5 (RB5) photoelectrochemical oxidation and simultaneous hydrogen generation in a two compartment PEC reactor. The photoanode`s performance was compared to the pure Ti/TiO2 nanotubes and W/WO3 nanoporous electrodes. The best experimental conditions leaded to 100% dye discoloration in the presence of TiO2, WO3 e TiO2/WO3 under mercury lamp irradiation, 73, 80 and 85% mineralization and satisfactory hydrogen generation estimated efficiencies of 43, 34 and 46%, respectively. Hydrogen generation was confirmed by gas chromatography analysis (CG/TCD). Complete dye degradation was obtained under UV and visible light irradiation of Si/TiO2/Pt photanodes and 30% of estimated hydrogen generation efficiency and 0,5 mA cm-2 photocurrent response under mercury lamp irradiation under the best experimental conditions. Dye removal and by-products generation were confirmed by LC-MS/MS by the detection of m/z 137, 280, 210, 297...O presente trabalho tem por objetivo explorar o uso de sistemas fotoeletroquímicos baseados em semicondutores bicomponentes nanoestruturados de Ti/TiO2/WO3 preparados por moldes de poliestireno (templates) e Si/TiO2/Pt preparado por junção metalica. A sintese desses materiais foi realizada por anodização e deposição eletroquímica e a presença do TiO2 na fase anatasio e WO3 monoclínico foi confirmada por difração de raios–X e EDS. Analises de espectroscopia de reflectancia difusa (DRS) mostraram que o material bicomponente possui absorção na região do visível pela observação do red shift. A caracterização eletroquímica foi realizada por medidas de voltametria linear sob irradiação UV e visível por diferentes lâmpadas: de vapor de mercúrio de alta pressão de 125 W e xenônio de 150 W com filtros que isolam a contribuição UV e visível. Maior fotocorrente foi obtida pela irradiação com a lâmpada de Hg de 11,0 mA cm-2 enquanto que na presença da lâmpada de Xe os valores obtidos foram de cerca de 0,4 mA cm-2. Posteriormente, os eletrodos de TiO2/WO3 foram aplicados na oxidação fotoeletrocatalítica do corante têxtil preto reativo 5 (RB5) e concomitante geração de hidrogênio em um reator de dois compartimentos. Seu desempenho foi comparado ao dos eletrodos de Ti/TiO2 e W/WO3. As melhores condições experimentais levaram a 100% de descoloração do corante para os eletrodos de Ti/TiO2, W/WO3 e Ti/TiO2/WO3 sob iluminação pela lâmpada de vapor de Hg, mineralização de 73, 80 e 85% e a produção de hidrogênio também revelou rendimentos estimados satisfatórios de 43, 34 e 46%, respectivamente. A natureza do gás H2 foi confirmada por cromatografia gasosa (CG-TCD). Completa remoção do corante RB5 também foi obtida para o fotoanodo de Si/TiO2/Pt e eficiencia estimada da geração de H2 foi de 30% com valores de fotocorrente da ordem de 0,5 mA cm-2 sob irradiação pela lâmpada de vapor de Hg nas melhores..

Dataset for "Photocatalytic ZnO foams for micropollutant degradation"

Photocatalytic foams can concomitantly overcome the disadvantages of slurries and immobilised photocatalysts for water treatment. So far, foam synthesis has been restricted to nanoparticles grafting onto foam substrates. This approach can still release nanoparticles into the environment. The paper associated with this dataset, "Photocatalytic ZnO foams for micropollutant degradation" describes for the first time the synthesis of self-supporting, highly porous photocatalytic zinc oxide (ZnO) foams produced using a combination of liquid templating and sintering. Systematic changes in sintering times and temperature affected the foams’ morphology and structure, in turn controlling their photocatalytic activity (PCA) and stability. This dataset contains the photocatalytic degradation and Carbamazepine calibration data underpinning these results, alongside measurements of Zn concentration in the solution after photocatalysis (ICP/MS), X-ray diffraction data, and Transmission and Scanning Electron Microscopy (TEM/SEM) images.All experimental details including sampling, procedures and methodologies are fully described in the associated manuscript.All technical details are fully described in the associated manuscript. Origin Software (version 2017 Academic 64 bit) was used to create the Figures presented in the manuscript.The spreadsheet contains the following tabs: • Data for photocatalytic degradation using ZnO foams in Figures 4, 5, 6 and 7 in the paper, respectively; • SEM and FE-SEM original micrographs in the manuscript (Figures 2 and 7) and ESI (Figure S.1 and Figure S.2); • X-ray diffraction data for Figure S.3 in the ESI; • BET data for Figure S.4 in the ESI; • HPLC calibration data for Carbamazepine; • Zn concentration calculations (ICP/MS); • Quantum efficiency

Dataset for "Highly efficient ZnO photocatalytic foam reactors for micropollutant degradation"

Photocatalytic foams combine the advantages of slurries and immobilised photocatalysts for water treatment. The paper associated with this dataset, "Highly efficient ZnO photocatalytic foam reactors for micropollutant degradation" describes the performance of ZnO photocatalytic foams in recirculation and single-pass configuration reactors. The photocatalytic activity was systematically studied for flow rate, catalyst length and stability parameters using Carbamazepine (CBZ) as a model pollutant. This dataset contains Carbamazepine photocatalytic degradation data underpinning these results. Materials characterisation data comprises Zn concentration in the solution after photocatalysis (ICP/MS), X-ray diffraction data and Scanning Electron Microscopy (TEM/SEM) images. Simulation results are provided from the code developed in Matlab and compared to experimental data.All experimental details including sampling, procedures and methodologies are fully described in the associated paper.All technical details are fully described in the associated paper. Origin Software (version 2017 Academic 64 bit) was used to create the Figures presented in the manuscript and Blender for the graphical abstract. Simulation data was perfomed using Matlab 2021 software.The spreadsheet contains the following tabs: • Data for photocatalytic degradation using ZnO foams in Figures 3, 4, 5, and S2 in the manuscript, respectively; • SEM and FE-SEM original micrographs in the manuscript (Figures 2) and ESI (Figure S4); • X-ray diffraction data for Figure S.1 in the ESI; • HPLC calibration data for Carbamazepine; • Zn concentration; • Quantum efficiency and EEO (Tables 1 and 3); • UV dose data Figures 3 and 5 in the manuscript, Figure S2 ESI and Tables S4 and S5 ESI; • Hydrodynamics parameters Tables S6 and S7 ESI • Simulation: Figure 7 in the manuscript, Figures S5 to S8 ESI and Tables S10 and S11

Dataset for Synthesis of Photocatalytic Pore Size-Tuned ZnO Molecular Foams

Raw data files for XRD, HPLC, UV dosage, ICPMS, Eeo, MicroCT and hydrodynamic calculations associated with manuscript titled "Synthesis of Photocatalytic Pore Size-Tuned ZnO Molecular Foams" XRD contains raw data of XRD spectra used to analyse crystallinity and crystal phase of ZnO samples. HPLC contains the raw data used to produce degradation profiles of carbamazepine when exposed to the photocatalyst. UV dosage contains the raw data used to plot degradation against UV irradiation supplied to allow for greater analysis between flow rates of reactor. ICPMS contains the raw data collected to analyse the concentration of metal in the pollutant stream, allowing for analysis of material stability. Eeo contains the calculations used to work out the electrical energy efficiency of the system, allowing for analysis of efficiency when operating the reactor under different conditions. MicroCT is the raw data collected from analysis of the 3D reconstruction of the samples, used to analyse the pore structure (size, sphericity, ect) Hydrodynamic calculations contains the calculations conducted to understand the reactor system and to calculate key parameters allowing for the discussion of the reactor.XRD - sampling between 2 Theta of 20 - 90 with Cu K alpha xrays. HPLC - degradation experiments used 1 mL samples taken every 15 or 30 minutes. Analysis was performed on a Thermo Scientific Ultimate 3000 liquid chromatograph with a UV detector. CBZ analysis used a Thermo Scientific Acclaim 120 C18 column (3.0 X 75.0 mm, particle size 3.0 µm) and a Thermo Scientific Acclaim 120 C18 guard column (R) 120 C18 (3.0 X 10.0 mm, particle size 5.0 µm) The mobile phase was made up using 5.0 mM phosphoric acid and acetonitrile 70:30 (v:v) with a flow rate of 0.8 mL min-1, injection volume of 20 µL and detection wavelength of 285 nm. ICPMS - All samples, standards and blanks, were spiked with internal standard elements Be, In, and Re. The Zn concentration was calibrated using six synthetic standards prepared from a 1000 ppm Inorganic Ventures (VA, USA) standard. MicroCT - Data collected using a Nikon XT H 225 ST using a 178 kV x-ray source and 0.708 second exposure time, 3141 projections and 4 frames per projection and analysed using Thermo Scientific Avizo Software 9 3D data visualisation software