Solar Photocatalytic Processes Research Articles

Heterostructured g-C3N4-TiO2 nanocomposites applied to p-toluic acid degradation under solar light-induced photocatalytic process

In this work, heterostructured photocatalysts were prepared with TiO2-P25 nanocrystals dispersed on two-dimensional layers of g-C3N4. Different g-C3N4:TiO2 ratios (25 %, 50 % and 75 %) were prepared using a wet method under ultrasonic exfoliation and thermal treatment under an oxidizing atmosphere. The heterojunctions were confirmed by X-ray diffraction, and electron microscopy, showing TiO2 nanocrystals anchored onto the surface of the g-C3N4 structure. The obtained heterojunctions increased light absorption from the ultraviolet to the visible spectrum and reduced the recombination of photoinduced charge carriers confirmed by photoluminescence and band gap energy (Eg) measurements. The photocatalytic performance was evaluated in the degradation of p-toluic acid (p-TA) (20 mg L–1) under UVA LED at 365 nm, a polychromatic lamp (UVA-UVB-visible) and solar radiation. The g-C3N4:TiO2 ratio of 25 % showed the best performance, reaching 95 % degradation after 180 min under solar radiation. The reuse tests showed that the mineralization capacity determined by total organic carbon (TOC) remained stable for 6 cycles, achieving 80.8 % TOC degradation. The heterojunction induced a significant alteration in the rheological behavior of the suspension, which made the g-C3N4-TiO2 easily recoverable, unlike the pure TiO2. The radical scavengers study indicated that the superoxide anion radical (O2•–) is the main oxidative species in p-TA photodegradation on g-C3N4-TiO2 photocatalyst. The greatest advantage of the g-C3N4 in the composite was the absorption of light in the visible range and facile catalyst recovery for reuse while presenting photocatalytic activity similar to TiO2.

Solar photocatalytic process using biomass-derived boron carbon nitride (BM-BCN) for the treatment of synthetic textile effluent

This research elucidates the process of synthesizing, characterizing, and evaluating the removal efficiency of a pioneering biomass-derived non-metal photocatalyst BM-BCN. Within this framework, an efficient one-step synthesis method is presented for generating BM-BCN. This material is produced by subjecting a blend of boric acid, citron peel powder, and melamine to pyrolysis. The BM-BCN material exhibited an optical band gap of 2.5 eV, closely resembling the property of a visible light-responsive photocatalyst. It is characterized by intricate porous structure, remarkably expansive surface area, and distinct chemical bonds, porous BM-BCN sheets present considerable benefits in terms of their photocatalytic behavior. The synthesized material showed its maximum photocatalytic performance of 98.32% when degrading indigo carmine (IC) dye under acidic pH conditions, employing 300 ppm of catalyst dosage for 10 ppm of dye concentration over a 180-minute exposure to direct sunlight, confirming the pseudo-first-order kinetics model. Additionally, this scientific study details the mechanism of IC photocatalytic decolorization. The porous BM-BCN sheets showed exceptional stability over extended cycling of 92% or higher throughout five successive iterations.

Treatment of Textile Industry Wastewater by Using Solar Photocatalytic Process: Experimental Studies & Statistical Optimization

Treatment of Textile Industry Wastewater by Using Solar Photocatalytic Process: Experimental Studies & Statistical Optimization

Analyzing pH-dependent structural characteristics and optical transmittance of titanium dioxide

AbstractThe use of titanium dioxide (also known as titania) in solar cells, biomaterials, and photocatalytic processes has generated an ever-increasing amount of interest. Titania is widely used in a variety of applications because it is nanocrystalline, chemically stable, has a high refractive index, is mechanically hard, and transmits visible light well. In this work, titania nanoparticles were formed via sol–gel synthesis, wherein the effect of varying pH values such as 3, 5, 7, 9, and 11 has been investigated on the synthesized nanoparticles by studying their structural characteristics and analyzing their optical transmittance. Structural analysis of the synthesized TiO2shows formation of the brookite phase at all pH values under as-synthesized conditions. Moreover, structural parameters including crystallite size, dislocation density, and unit cell volume were also calculated. Cell volume was calculated at various pH levels and measured between 255.7 and 257.2 Å3. Optical analysis shows a transmission increase with a pH increase, and maximum transmission has been observed above 80% for a pH value of 11.

Photocatalytic Degradation of Inherent Pharmaceutical Concentration Levels in Real Hospital WWTP Effluents Using g-C3N4 Catalyst on CPC Pilot Scale Reactor.

The objective of this work was to evaluate the efficiency of a solar photocatalytic process using g-C3N4 as photocatalyst on the degradation of pharmaceutical compounds detected in hospital wastewater treatment plant secondary effluents. A compound parabolic collector pilot plant, established in the secondary effluent stream of the Ioannina city hospital wastewater treatment plant, was used for the photocatalytic experiments. The analysis of the samples before and after the photocatalytic treatment was accomplished using solid phase extraction (SPE), followed by UHPLC-LTQ/Orbitrap HRMS. Initial effluent characterization revealed the presence of ten pharmaceutical compounds. Among these, amisulpride, O-desmethyl venlafaxine, venlafaxine and carbamazepine were detected in all experiments. Initial concentrations ranged from 73 ng L-1 for citalopram to 2924.53 ng L-1 for O-desmethyl venlafaxine. The evolution of BOD5 and COD values were determined before and after the photocatalytic treatment. All detected pharmaceuticals were removed in percentages higher than 54% at an optimum catalyst loading ranging between 200 and 300 mg L-1. The potential of the catalyst to be reused without any treatment for two consecutive cycles was studied, showing a significant efficiency decrease.

Semiconductor Synthesis and Application for the Treatment of Ciprofloxacin Antibiotic by Solar Heterogeneous Phocatalysis

The objective of this study is to examine the relevance of treatment with the antibiotic ciprofloxacin by heterogeneous solar photocatalysis. The efficiency of the catalyst (ZnO) synthesized by the precipitation method is also determined. The solid- visible UV analysis showed that the spectrum reveals an absorption peak at 364 nm, which can be attributed to the band gap with of ZnO, in the case of the electron transition from the band of valence towards the conduction band (2p 3d) [3] and [4]. Under optimal conditions, initial ciprofloxacin concentration 10 ppm, ZnO dose 0.1 g/L and free pH (6) ; treatment by solar photocatalysis in the presence of ZnO showed a ciprofloxacin elimination yield of 87% is obtained after 240 min of treatment. The total degradation of ciprofloxacin is observed, by the disappearance of the ciprofloxacin absorption peak during the treatment time. Analysis by infrared spectroscopy showed that only two groups are obtained O-H and C=O at 3500 cm-1 and 1600 cm-1, respectively after 240 min of oxidation. The BOD5/COD ratio increased from 0.005 initially to 2.13 after 240 min of ciprofloxacin treatment by solar photocatalysis. The relevance of the solar photocatalytic process is shown. At the end of these results, the relevance of the treatment of ciprofloxacin antibiotic by solar photocatalysis in the presence of the semiconductor ZnO is shown.

Fe3O4-TiO2 Thin Films in Solar Photocatalytic Processes.

The optical properties of 5wt% Fe3O4-TiO2 thin films were evaluated in detail with the aim of proposing a mechanism for solar photocatalytic processes and highlighting the advantages over the use of bare TiO2. The results showed that the incorporation of 5wt% Fe3O4 enhanced the optical properties by a redshift to a wavelength in the visible range, reducing the anatase/rutile band gap energy from 3.2 eV to 2.8 eV. Photoluminescence studies reveal a superior separation efficiency of photoexcited electron-hole pairs when Fe3O4 nanoparticles (NPs) are present in the photocatalyst. X-ray photoelectron spectroscopy spectra confirm the presence of Fe3O4 and existence of a chemical bonding between TiO2 and Fe3O4 NPs. Moreover, in this study, a mechanism of solar photocatalytic processes involving Fe3O4-TiO2 thin films is proposed and it is supported by experimental results. Finally, solar photocatalytic experiments were carried out, indicating that the effectiveness for the removal of the selected pharmaceutical is considerably improved when the composite material is used as catalyst. Furthermore, it was demonstrated that the photocatalytic activity of the prepared Fe3O4-TiO2 thin films depends on their thickness, achieving the highest pharmaceutical removal yields using the 2 µm thick sample. The stability and reusability of the catalyst was confirmed studying the photocatalytic activity over three cycles.

Solar photocatalytic degradation of total organic halogen in water using TiO2 catalyst

Disinfection byproducts (DBPs) in treated wastewater effluents pose environmental and health risks during water reuse. Solar-TiO2 photocatalysis is a promising technology for degrading organic pollutants in treated effluents. In this study, total organic halogen (TOX) was used as an analytical tool to determine the efficiency of solar-TiO2 photocatalytic process for the dehalogenation of DBPs in water. Natural solar photocatalytic experiments using TiO2 particles were conducted to evaluate dehalogenation kinetics of different TOX groups formed by fulvic acid including total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI). The results showed that the mixed phase TiO2 (Aeroxide P25) was much more effective at TOX removal than the anatase (Hombikat UV-100) and rutile (TiOxide) TiO2 particles. The TOX photocatalytic degradation rates of different halogen substituents ranked as TOI > TOCl (NH2Cl) > TOBr > TOCl (Cl2). The TOX removal followed first-order kinetics with half-lives of 42.8, 11.0, 5.0 and 2.7 min for TOCl (Cl2), TOBr, TOCl (NH2Cl), and TOI, respectively, at the 100 mg L−1 TiO2 dose. The TOX dehalogenation was enhanced at pH 9 compared to pH 5, and the addition of hydrogen peroxide had limited improvement in the TOX removal. Hydrophobic and molecular weight (MW) > 1 kDa fractions of TOCl (Cl2) were more susceptible to the solar photocatalytic process than the hydrophilic and MW < 1 kDa fractions. The solar-TiO2 photocatalytic process also effectively removed TOX in chlorinated and chloraminated wastewater samples. The results of this study suggest that the solar-TiO2 photocatalysis is an effective treatment technology for TOX removal in water reuse.

Heterogeneous alternative catalysts: A bibliometric and systematic evaluation of their application in solar photocatalytic processes

AbstractThe present study sought to objectively demonstrate how a researcher can, in a structured way, select relevant articles about alternative heterogeneous catalysts in photocatalytic processes. Therefore, the ProKnow‐C (Knowledge Development Process – Constructivist) method was used to systematize the results found, with the application bibliometric and systematic analysis techniques for the evaluation of the results. The search string adopted as criteria was: solar photocatalysis AND heterogeneous catalysts OR alternative catalysts AND effluents. The databases were Web of Science, Science Direct and Scopus. The final bibliographic portfolio obtained for the research theme was made up of 19 articles. It was possible to verify advances in the number of publications on the theme over the evaluated period, with the Journal of Photochemistry and Photobiology A: Chemistry standing out in the final portfolio. Evaluating each article in the portfolio individually, it was possible to verify that most studies use combinations of catalysts already reported to create an alternative material to those already investigated in the literature. Those that use waste as catalysts chose to source this material from treatment plants and the steel industry. Around 58% of the papers used hydrogen peroxide in their processes, while 42% chose not to use it. Finally, approximately 63% of the papers in the portfolio used synthetic effluent in their processes, while the rest (37% of the research) chose to use real effluent. The results obtained in this research by applying the method can contribute to studies related to heterogeneous photocatalysis by alternative means over the years.

Arsenite to Arsenate Oxidation and Water Disinfection via Solar Heterogeneous Photocatalysis: A Kinetic and Statistical Approach

Arsenic (As) poses a threat to human health. In 2014, more than 200 million people faced arsenic exposure through drinking water, as estimated by the World Health Organization. Additionally, it is estimated that drinking water with proper microbiological quality is unavailable for more than 1 billion people. The present work analyzed a solar heterogeneous photocatalytic (HP) process for arsenite (AsIII) oxidation and coliform disinfection from a real groundwater matrix employing two reactors, a flat plate reactor (FPR) and a compound parabolic collector (CPC), with and without added hydrogen peroxide (H2O2). The pseudo first-order reaction model fitted well to the As oxidation data. The treatments FPR–HP + H2O2 and CPC–HP + H2O2 yielded the best oxidation rates, which were over 90%. These treatments also exhibited the highest reaction rate constants, 6.7 × 10−3 min−1 and 6.8 × 10−3 min−1, respectively. The arsenic removal rates via chemical precipitation reached 98.6% and 98.7% for these treatments. Additionally, no coliforms were detected at the end of the process. The collector area per order (ACO) for HP treatments was on average 75% more efficient than photooxidation (PO) treatments. The effects of the process independent variables, H2O2 addition, and light irradiation were statistically significant for the AsIII oxidation reaction rate (p &lt; 0.05).

Remarkable Recycling Process of ZnO Quantum Dots for Photodegradation of Reactive Yellow Dye and Solar Photocatalytic Treatment Process of Industrial Wastewater.

The mineralization of five industrial sunlight-exposed wastewater samples was investigated, and the recycling process of ZnO quantum dots (ZQDs) for five reusable times was estimated under the approved Egyptian Environmental Law COD (Chemical Oxygen Demand), which has to be less than 1000 ppm. An improved sol-gel process at a low calcination temperature that ranged between 350 and 450 °C was employed to synthesize ZnO quantum dots (ZQDs). The purity, high crystallinity, and structure of the prepared catalysts were determined by TEM and XRD analysis. The energy bandgap, the crystal size values, and the surface area for Z1 and Z2 were determined based on the TEMs, DRSs, and EBTs, which were equal to 6.9 nm, 3.49 eV, and 160.95 m2/g for Z1 and 8.3 nm, 3.44 eV, and 122.15 m2/g for Z2. The investigation of the prepared samples was carried out by studying the photocatalytic activity and photoluminescence, and it was found that the degradation rate of reactive yellow dye as an industrial pollutant of the Z1 sample was significantly higher than other samples, by 20%. The data collection has shown that photocatalytic efficiency decreases with an increase in the crystallite size of ZQDs.

Optimization and kinetic evaluation of reactive yellow dye degradation by solar photocatalytic process

Optimization and kinetic evaluation of reactive yellow dye degradation by solar photocatalytic process

Degradation of local Brilliant Blue R dye in presence of polyvinylidene fluoride/MWCNTs/TiO2 as photocatalysts and plasma discharge

The need of clean water and the water-poor are increasing daily in the world. In addition, we are facing a dramatic increase in the industrial pollutions of rivers and groundwater, which led us to find a new way to treat industrial pollutants. The plasma discharge technique is one of the important, safe, and applicable for industrial wastewater decontamination. Decolorization of Brilliant Blue R (BBR) dye as a hazard material was noticed when the contaminated solution was exposed to the plasma discharge technique. The combination between the nonthermal plasma and catalysts was evaluated in this work to optimize the degradation efficiency. The PVDF/(MWCNTs/TiO2) as three system composites was employed to enhance the nonthermal plasma performance. The surface area, phase purity, shape, and photonic efficiency were characterized employing XRD, FTIR, SEM, DSC, and UV–Vis. techniques. The obtained results of degradation using NTP technique in presence of the PVDF/MWCNTs catalyst have been enhanced the BBR dye degradation by 19% than only plasma treatment for 20 min. The durability processes of prepared PVDF/(MWCNTs/TiO2) was investigated and evaluated until 8 solar photocatalytic process repeating times.

Improved Interfacial Charge Transfer on Noble Metal‐Free Biomimetic CdS‐Based Tertiary Heterostructure @ 2D MoS2‐CdS‐Cu2O with Enhanced Photocatalytic Water Splitting

AbstractHigh charge separation efficiency with a wide optical absorption window is the prime requirement for the scale up of a stable solar photocatalytic hydrogen generation process. A new noble metal‐free heterostructure of 2D MoS2‐CdS‐Cu2O is designed by depositing cauliflower‐shaped CdS and nanosized Cu2O on exfoliated 2D MoS2. Characterization by XPS, high‐resolution transmission electron microscopy (HRTEM), and UV‐visible spectra confirms the formation of nanosized Cu2O with desired interface formation with MoS2 sheet and CdS thus extending the optical absorption range up to 900 nm. Water splitting activity in the presence of lactic acid is found to be 7.89 and 11.53 mmol g−1 h−1 on MoS2‐CdS and MoS2‐CdS‐Cu2O, respectively, with good repeatability under visible light. Efficient interfacial charge separation is manifested from demised photoluminescence (PL) intensity which supports the suppression of hole‐electron recombination in the tertiary heterostructure. In addition, the formation of dual p‐n junction as indicated from Mott–Schottky analysis further strengthen the faster electron and holes separation objective. Compared to the pure CdS, hydrogen efficiency is 20.96 times higher on a noble metal‐free tertiary catalyst with an apparent quantum efficiency of 8.75%. Hopefully, the 2D material‐based architecture of dual p‐n junction with desired interface engineering will facilitate the catalyst design with increased water splitting activity under solar/visible light.

Zinc oxide quantum dots: Confinement size, photophysical and tunning optical properties effect on photodecontamination of industrial organic pollutants

Confinement size effect and tunning optical properties of Zinc oxide quantum dots (ZDs) observed via modified wet chemical preparation method. The purity, high crystallinity, and elongated structure of ZDs investigated by XRD and TEM tests. The crystallized size values, the bandgap energy, and the active surface area for ZD1 and ZD2 determined based on the TEMs, DRSs, and EBTs are 2.9 and 3.6 nm, 3.57 eV and 3.54 eV, and 312.10 m2/g and 278.05 m2/g, respectively. Absorption and fluorescence spectra shifted for ZDs from 340 to 315 nm and from 530 to 500 nm, respectively, due to its confinement effect of their small sizes. The prepared samples revealed that the photocatalytic activity of ZD1 is higher than ZD2 by 20%. Photocatalytic activity of ZDs by the photodegradation process of Coomassie Brilliant Blue R dye as an industrial organic pollutant evaluated (used in textile and dyeing manufactories) by xenon photoreactor and solar photocatalytic processes. The observed results have shown that photocatalytic efficiency increases with crystallite size decreasing. And, the variation between the photocatalytic activity of ZDs prepared samples by the solar photocatalytic process is higher than that observed by the Xenon photoreactor. And their photodegradation rates values are lower than that obtained by the Xenon photoreactor. A similar finding for the recycling process after nine reptation times of using ZDs during all photodegradation processes signified obtained.

Removal Kinetics of Four Leacher Herbicides Through Solar Heterogeneous Photocatalysis as Influenced by Water Matrix Components

This work focuses on the effect of dissolved substances on the photocatalytic degradation of four herbicides, metribuzin and terbuthylazine (triazine) and chlorotoluron and isoproturon (phenylurea) in three different water matrix (deionized, mineral and leaching water). To study the effect of heterogeneous photocatalysis on their degradation, TiO2 and ZnO were used as photocatalysts in tandem with an oxidant (Na2S2O8). Results show that the addition of both semiconductor materials significantly enhances degradation of the herbicides although in different proportions. Similar effectivity of both photocatalyst, assessed as a function of the mean half-lives calculated, was observed (85 and 87min for TiO2 and Zn, respectively), while the mean half-life in the photolytic experiment was markedly higher (265min). The degradation rate was in the order: metribuzin > chlorotoluron ≈ isoproturon > terbuthylazine. A faster degradation was observed in all cases in deionized water as compared to mineral and leaching water indicating that the presence of dissolved salts and organic matter considerably slows down the effectiveness of the treatment. Although after 180min of treatment, total mineralization was not achieved in mineral and leaching water, this technology considerably reduces the pollutant load in complex water matrices. Therefore, solar heterogeneous photocatalytic processes, especially those involving ZnO and TiO2 as photocatalysts, offers a valuable tool for surface and groundwater remediation, especially in those areas receiving a large number of hours of sunshine per year.

Insights into the Stability and Activity of MIL-53(Fe) in Solar Photocatalytic Oxidation Processes in Water

MIL-53(Fe) is a metal organic framework that has been recently considered a heterogeneous photocatalyst candidate for the degradation of water pollutants under visible or solar radiation, though stability studies are rather scarce in the literature. In this work, MIL-53(Fe) was successfully synthesized by a solvothermal method and fully characterized by X-ray diffraction (XRD), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), N2 adsorption–desorption isotherm, Thermogravimetric analysis coupled with mass spectrometry (TGA-MS), UV-visible diffuse reflectance spectroscopy (DRS), elemental analysis and wavelength dispersive X-ray fluorescence (WDXRF). The effects of pH, temperature, solar radiation and the presence of oxidants (i.e., electron acceptors) such as ozone, persulfate and hydrogen peroxide on the stability of MIL-53(Fe) in water were investigated. The as-synthetized MIL-53(Fe) exhibited relatively good stability in water at pH 4 but suffered fast hydrolysis at alkaline conditions. At pH 4–5, temperature, radiation (solar and visible radiation) and oxidants exerted negative effect on the stability of the metal–organic framework (MOF) in water, resulting in non-negligible amounts of metal (iron) and linker (terephthalic acid, H2BDC) leached out from MIL-53(Fe). The photocatalytic activity of MIL-53(Fe) under simulated solar radiation was studied using phenol and metoprolol as target pollutants. MIL-53(Fe) on its own removed less than 10% of the pollutants after 3 h of irradiation, while in the presence of ozone, persulfate or hydrogen peroxide, complete elimination of pollutants was achieved within 2 h of exposure to radiation. However, the presence of oxidants and the formation of some reaction intermediates (e.g., short-chain carboxylic acids) accelerated MIL-53(Fe) decarboxylation. The findings of this work suggest that MIL-53(Fe) should not be recommended as a heterogeneous photocatalyst for water treatment before carrying out a careful evaluation of its stability under actual reaction conditions.

Recycling of supported nanocomposites for hazardous industrial wastewater treatment via Solar photocatalytic process

Study of the photocatalytic activity of the synthesized polyvinylidene fluoride/multi-walled carbon nanotubes/titanium dioxide (PVDF/x%(MWCNTs/8%TiO2) nanocomposites using a simple modified solvent casting technique in decontamination of hazardous industrial wastewater and Reactive Yellow 145 dye as an industrial organic pollutant (local textile dye) were evaluated. Also, different MWCNTs/8%TiO2 weight percentages in PVDF/x%(MWCNTs/8%TiO2) nanocomposites were prepared and evaluated. The surface morphology and the structures of the synthesized samples were characterized using SEM, ATR-FTIR, DRS, XRD, and BET. The evaluated bandgap values for MWCNTs/xTiO2 nanocomposites are from 2.38 to 2.69 based on the weight ratios (2%, 5%, and 8%). The results of the surface area of samples and the best optical behavior obtained at MWCNTs/8%TiO2 are reported and its photodegradation rate raised to 10.22x10−3S−1. The photodegradation process of Reactive Yellow 145 dye by PVDF/x%(MWCNTs/8%TiO2) nanocomposites was monitoring using chemical oxygen demand (COD). Also, the observed PL intensity for PVDF/MWCNTs/8%TiO2 has high photonic efficiency and photocatalytic activity. The solar photocatalytic process efficiency for an Egyptian dying factory by repeating it 10 times using PVDF/10%(MWCNTs/8%TiO2) nanocomposites as a supported photocatalyst for the industrial wastewater treatment was evaluated by the COD method and still under Egyptian environmental law allowed COD limit (1000 ppm).

Adsorption-photocatalytic processes for removal of pentachlorophenol contaminant using FeNi3/SiO2/ZnO magnetic nanocomposite under simulated solar light irradiation.

The adsorption followed by photocatalytic degradation process was examined for the pentachlorophenol (PCP) removal from aqueous solution. These processes were accomplished by using FeNi3/SiO2/ZnO magnetic nanocomposite as an adsorbent-photocatalytic agent and under the irradiation of solar light. The magnetic nanocomposite used was first synthesized and then was characterized using transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), vibrating-sample magnetometer (VSM), and X-ray diffraction (XRD) spectroscopy. The PCP removal efficiency was tested for various factors, including pH, PCP concentration, and nanocomposite dose at different contact times. The characterization results of TEM, FE-SEM, and VSM analysis showed that the synthesized nanoparticles are amorphous and tend to agglomerate due to their high super-paramagnetic property. In addition, the EDX technique showed that the Zn and O elements had the highest weight percent in the synthesized nanocomposite, respectively. On the other hand, XRD analysis revealed that the crystalline size of the nanoparticles was about 42 nm. The kinetic of PCP degradation followed the pseudo-first-order model with R2 = 0.978. According to the results of the isotherm study, the adsorption of PCP onto the nanoparticles followed the Freundlich model. The results of adsorption-photocatalytic degradation experiments showed that 100% removal of PCP was obtained at optimum conditions of pH = 3, nanocomposite dose = 0.5 g/L, contact time = 180 min, and initial PCP concentration of 10 mg/L. Through the results obtained from this study, the adsorption process followed by solar light photocatalytic degradation process using FeNi3/SiO2/ZnO magnetic nanocomposite is found to be an efficacious treatment method for the removal of PCP contaminant from water and wastewater.

Efficient hydrogen production through the chemical looping redox cycle of YSZ supported iron oxides

The chemical looping process, where an oxygen carrier is reduced and oxidized in a cyclic manner, offers a promising option for hydrogen production through splitting water because of the much higher water splitting efficiency than solar electrocatalytic and photocatalytic process. A typical oxygen carrier has to comprise a significant amount of inert support, to maintain stability in multiple redox cycles, thereby resulting in a trade-off between the reaction reactivity and stability. Herein, we proposed the use of ion-conductive yttria-stabilized zirconia (YSZ) support Fe2O3 to prepare oxygen carriers materials. The obtained Fe2O3/YSZ composites showed high reactivity and stability. Particularly, Fe2O3/YSZ-20 (oxygen storage capacity, 24.13%) exhibited high hydrogen yield of ∼10.30 mmol g−1 and hydrogen production rate of ∼0.66 mmol g−1 min−1 which was twice as high as that of Fe2O3/Al2O3. Further, the transient pulse test indicated that active oxygen diffusion was the rate-limiting step during the redox process. The electrochemical impedance spectroscopy (EIS) measurement revealed that the YSZ support addition facilitated oxygen diffusion of materials, which contributed to the improved hydrogen production performance. The support effect obtained in this work provides a potentially efficient route for the modification of oxygen carrier materials.