Removal Of Organic Pollutants Research Articles

Modulated Fe Central Spin State in FeCu4 Alloy Nanoparticles for Efficient and Selective Activation of H2O2

AbstractIn advanced oxidation processes, the efficient activation of H2O2 and the selective production of reactive oxygen species are the key steps to achieve the removal of organic pollutants in the water environment. Studies have shown that the precise regulation of catalyst metal active sites can break through the limitation of H2O2 activation and realize the efficient selective conversion of H2O2. Therefore, FeCu bimetallic active sites are developed by constructing FeCu4 alloy nanocluster metal catalyst (FeCu/NC). The introduction of Cu metal sites realized charge redistribution, promoted rapid electron transfer, reduced the spin state of Fe in the catalyst, diminished the interaction between Fe and O, weakened the strong and persistent adsorption between Fe center and *H2O2, lowered the energy barrier of intermediate products in hydroxyl radicals (·OH) generation process, achieved efficient activation of H2O2 and selective generation of ·OH. In addition, a complete electron circulation path is formed between FeCu active sites and the substrate, breaking the contradiction between single metal and H2O2 redox relationship, promoting efficient reduction of Fe3+ to Fe2+. The first‐order kinetic constant (kobs) of FeCu/NC is 0.081 min−1, which is 3.68 and 7.36 times higher than those of single Fe metal species (FeFe/NC) and single Cu metal species (CuCu/NC) catalysts, respectively, and has excellent catalytic performance).

Rapid laser printing of cost-effective, scalable and flexible carbon-based fabrics for solar water evaporation

Solar interfacial evaporation represents a sustainable, cost-effective and carbon-neutral approach for freshwater scarcity. Nevertheless, most of the solar water evaporator face challenges related to scalability, flexibility and theoretical evaporation limit. Moreover, the poor stability in harsh water environments and high-cost of evaporators significantly restrict their industrial potential. The simultaneous optimization of high evaporation rates, environmental resistance and economic viability in a single device remains a rare accomplishment. Herein, a large-area black toner-fiber (BTF) composite film was rapidly produced with laser printing technology. Benefiting from the high photoabsorption of carbon black particles and the abundance of hydrophilic sites within the fabric fibers, the solar-thermal conversion efficiency is increased from 12.0 % to 85.3 %, and the water evaporation enthalpy is reduced to 1849.8 J g−1. The BTF-based evaporator possesses an evaporation rate of high as 1.51 kg m−2 h−1 under one sun. Furthermore, the evaporator also exhibits excellent properties on desalination and removal of organic pollutants, with an ion removal rate of ≈100 %. This design strategy for carbon-based evaporator offers a cost-effective, scalable alternative for tackling drinkable-water scarcity.

Activation of Peroxymonosulfate by a Mn0.7Co0.5O2@C Catalyst for the Degradation of Tetracycline

AbstractPersulfate advanced oxidation technologyshows great potential in the removal of organic pollutants. Inthis study, a Mn0.7Co0.5O2@C catalyst wassynthesized from MnCO3‐ZIF‐67 precursor via calcination and employedto activate peroxymonosulfate (PMS) for the degradation of tetracycline (TC).The catalyst, characterized by a plethora of active sites and superior electrontransfer capabilities, mitigated the sluggish reaction kinetics associated withweak electron transfer. Degradation experiments demonstrated an 87.54% removalefficiency within 60 minutes using 10 mg of catalyst, outperforming PMS aloneby 2.3‐fold. The Mn0.7Co0.5O2@C/PMS system'ssynergistic effects and mechanisms were elucidated, with experiments confirmingthe generation of reactive species including singlet oxygen (1O2), sulfate radicals (SO4•−), and hydroxyl radicals (•OH).The catalyst's exceptional performance is attributed to the valence cycling ofMn and Co ions, facilitating PMS activation and the production of radicals. Additionally, the lattice oxygen within the catalyst is oxidized to form reactive oxygenspecies, which, in conjunction with oxygen vacancies, react with PMS to producenon‐radical species (1O2). The synergistic oxidationeffects of these free radicals and non‐radicals ultimately facilitate theremoval of TC, offering a novel approach for the treatment of organicwastewater with persulfate‐based advanced oxidation processes.

Microwave assisted treatment of carpentry waste wood flour with natural deep eutectic solvents for nanocellulose production and removal of organic pollutants.

Row carpentry waste wood flour, constituted of poplar (∼60%) and fir (∼30%) biomass, was subjected for the first time to microwave-assisted deep eutectic solvent (DES) treatment, with the purposes of solubilizing lignin and hemicellulose, leaving cellulose as solid residue, thus performing a biorefinery. Several acidic (choline chloride/oxalic acid; choline chloride/citric acid; betaine hydrochloride/oxalic acid) and alkaline (urea/choline chloride; glycerol/K2CO3) DESs were employed under the same reaction conditions. Since the highest extraction yield was obtained by using choline chloride/oxalic acid DES, the use of the latter was investigated by varying some parameters (temperature, manner of microwave irradiation, addition of water) aiming at increasing the solubilization yield, which in fact in some cases reached satisfying values (60%) under mild conditions. The solid residues (SRs) recovered after all treatments with all tested DESs were characterized by Thermogravimetric Analysis (TGA), Attenuated Total Reflectance-Fourier Tranform Infrared Spectroscopy, Solid-State NMR Spectroscopy, and titration of surface acid groups. All SRs were also ultrasonicated to produce cellulose nanoparticles which were in turn characterised by transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses. In addition, the solid residues recovered from acidic DESs were able to decontaminate water from organic pollutants, such as p-nitrophenol, by an adsorption process. Thus, the proposed DES treatment efficiently converted carpentry waste wood flour into a valuable biomaterial useful for environmental decontamination.

Uncovering the causal relationships in plant-microbe ecosystems: A time series analysis of the duckweed cultivation system for biomass production and wastewater treatment

The complex interplay among plants, microbes, and the environment strongly affects productivity of vegetation ecosystems; however, determining causal relationships among various factors in these systems remains challenging. To address this issue, this study aimed to evaluate the potential of a data analytical framework called empirical dynamic modeling, which identifies causal links and directions solely from time series data. By cultivating duckweed, a promising aquatic plant for biomass production and wastewater treatment, we obtained a 63-day time series data of plant productivity, microbial community structure, wastewater treatment performance, and environmental factors. We confirmed that empirical dynamic modeling can identify the correct causal directions among temperature, light intensity and plant growth, solely from time series data. Extending the analysis to microbial community data suggested that the bacterial family Comamonadaceae positively affects host duckweed growth and nitrogen removal. Additionally, the predicted abundance of bacterial genes relevant to xenobiotics biodegradation was shown to have a positive effect on organic pollutant removal, supporting the significant role of bacterial metabolism in phytoremediation performance. These results demonstrate the effectiveness of empirical dynamic modeling in uncovering causal relationships within vegetation ecosystems, which are difficult to examine comprehensively through conventional experiment-based approaches.

Nanofluid-peroxydisulfate integrated volumetric solar interfacial evaporation system for water evaporation and organic pollutant removal

Solar evaporation exhibits significant potential for the treatment of high-salt organic wastewater. However, it's also confronted with challenges due to the accumulation of organic pollutants and salts in the concentrated wastewater following evaporation, which compromises the long-term stability of evaporation unit and complicates subsequent treatment processes. To address these challenges, a volumetric solar interfacial evaporation (V-SIE) system by integrating Fe3O4-H2O nanofluids and peroxydisulfate (PDS) were proposed in this study. In V-SIE system, Fe3O4 magnetic nanoparticles (NPs) were prepared as solar receivers to form a volume-absorbing solar energy interface and enhance evaporation efficiency. The results show that the evaporation rate was 1.412 kg/(m2·h) and the solar efficiency reached 93.75% as the temperature rose to 57.2 ℃. Additionally, the high thermal conductivity of Fe3O4 facilitated the effective heat transfer to the fluid and provided sufficient thermal energy to activate PDS, thereby removing 99.3% of Rhodamine B (RhB). Fe3O4 NPs effectively promoted the generation of reactive species including SO4•−, •OH, O2•− and 1O2 from PDS and the four main stages including N-de-ethylation, chromophore cleavage, ring-opening, and mineralization were proposed as the possible degradation pathway of RhB. This study provides a reference for developing V-SIE system and highlights the positive effect of nanofluids in advanced oxidation processes.

A flexible Ag2S QD sensitized TiO2 Janus photocatalytic nanofiber membrane for visible light organic pollutant degradation and COD removal

A flexible Ag2S QD sensitized TiO2 Janus photocatalytic nanofiber membrane for visible light organic pollutant degradation and COD removal

Efficient generation of Fe(IV) = O for water purification in periodate activation process: Reducing Fe orbital occupation and expanding electron transfer channel

The rapid generation of high-valent iron species (Fe(IV) = O) in AOPs has become a challenge for the removal of organic pollutants due to the high electron occupancy in the Fe 3d orbitals and low electron transfer efficiency. Herein, BN modified CuFe2O4 catalysts were constructed by in situ growth of CuFe2O4 nanoparticles on ultrathin BN nanosheets for periodate (PI) catalysis. Especially, the formed Fe-N interface sites not only reduce the electron occupation in the Fe 3d orbitals, but also expand the electronic transfer pathway, thus transforming the oxidation mechanism from one electron process to two electron process for facilitating the Fe(IV) = O and 1O2 generation in the CuFe2O4/BN/PI system. The bimetallic redox cycle between Fe and Cu realizes the accelerated conversion of Fe(III) to Fe(II), promoting the continuous and fast conversion of Fe(II) to Fe(IV) = O via two electron process. As a result, the developed CuFe2O4/BN/PI system exhibits excellent degradation efficiency for oxytetracycline (OTC), achieving 91.02 % OTC removal within 60 min, and maintains relatively high remove efficiency even under different water quality conditions. This research provides a new insight into the evolution of Fe(IV) = O and the deep mechanism of PI activation.

Preparation and photocatalytic performance of Cr/Sn BiOCl nanocomposites

Photocatalytic technology represents a promising approach for the removal of organic pollutants like drugs and antibiotics from water. However, the widespread implementation hinges on the development of efficient catalysts. In this study, a series of BiOCl nanoflower-shaped catalysts doped with varying concentrations of Cr and Sn metal ions were successfully synthesized using a solvothermal method. The photocatalytic efficacy of these materials was evaluated using the antibiotic ciprofloxacin (CIP) as a model pollutant. Among the synthesized catalysts, BCS-5 demonstrated the exceptional photocatalytic performance under visible light irradiation, degrading 90.88% of the CIP solution within 180 minutes, and a 1.9-times enhancement compared to that of pure BiOCl. Photoelectrochemical analyses revealed that doping with Cr and Sn altered the band structure of BiOCl, formed new energy levels that facilitated the separation of photogenerated charge carriers, thereby improved the photocatalytic efficiency of BCS-5 nanomaterials. Moreover, BCS-5 exhibited excellent cyclic stability, highlighting its promising potential for practical applications.

Enhanced degradation and mineralization of OFX in water: Triggering the shift of dominant role from •OH to O2•- in dielectric barrier discharge plasma system

Faced with the threat to water environment posed by non-standard antibiotic usage, enhanced removal and mineralization of ofloxacin (OFX) were achieved concurrently by adding MnFe2O4/MXene to trigger the dominant role of O2•- based on dielectric barrier discharge plasma (DBDP). The electron (e-)-hole (h+) pairs formed by the action of high-energy electrons or photons in DBDP on MnFe2O4/MXene created the majority of the O2•- through catalyzing H2O2 and O2. Besides, multiple advanced oxidation processes (AOPs), Fenton-like reaction and O3 catalysis for example, were also involved in the MnFe2O4/MXene-DBDP system. MXene effectively inhibited the recombination of e--h+ pairs, while also facilitating the charge transfer from Mn/Fe sites to the antibonding orbits of the adsorbed H2O2, O2 and O3. Notably, the predicted serial toxicities of potential intermediates confirmed the necessity of focusing on mineralization efficacy. This study provided a promising alternative for refractory organic pollutant removal and enriched the catalytic mechanism at the micro level.

Membrane fouling behaviors in membrane Fenton process without acid-base agents controlled by current density for nanofiltration concentrate treatment

Effective generation of H+ and OH− in the Fenton by electrodes is crucial for addressing the impact of acidity and alkalinity on the environment. In this study, electrolysis was coupled with membrane Fenton for nanofiltration concentrate treatment and membrane fouling behaviors were investigated. The effects of current density and dosage (H2O2 and Fe2+ ) were studied. According to the Box-Behnken design results, both current density and the dosages of H2O2 and Fe2+ positively influenced the removal of organic pollutants, with the former showing the most significant effect. Hydroxyl radical (•OH) oxidized the organic pollutants into intermediates, realizing a removal efficiency of 74.50 %. The anode oxidation and Fenton process effectively degraded fluorescent components, particularly humic acid-like substances. Ammonia nitrogen was degraded by active chlorine produced at the anode, with an average removal rate of 51.36 %. Additionally, an increase in current density enhanced ion exchange membrane fouling. Chemical composition analysis suggested that the membrane was primarily covered with hydroxide crystal substances. The ultrafiltration (UF) membrane analysis indicated that cake layer formation was responsible for the trans-membrane pressure (TMP) increase, and cake-complete was the primary mechanism contributing to UF membrane fouling. The membrane Fenton process without acid-base agents exhibits significant potential for contaminants removal from nanofiltration concentrate and is advantageous for cleaning membrane fouling.

Epigallocatechin gallate boosted Fe(II) activated peracetic acid process for coumarin degradation: Performance and mechanisms investigation

The Fe(II)/peracetic acid (PAA) process shows significant potential for the removal of organic pollutants due to the rapid reaction between Fe(II) and PAA. However, the slow reduction from Fe(III) to Fe(II) leads to the continuous or excess dosing of Fe(II) during practical application. In this study, epigallocatechin gallate (EGCG), a typical reagent extracted from green tea, was used to enhance the degradation of coumarin (COU) by Fe(II)/PAA for the first time. A complete elimination of COU (25 μM) was achieved in the presence of 50 μM Fe(II), 300 μM PAA, and 25 μM EGCG, exhibiting a kobs value of 0.108 min−1, which was 27 times higher than that observed with Fe(II)/PAA (0.004 min−1). Further, Fe(II)/EGCG/PAA demonstrated remarkable pH tolerance, with a COU removal efficiency exceeding 80 % across a pH range of 3–9. Mechanisms investigations revealed that •OH played a dominant role in COU degradation by Fe(II)/EGCG/PAA (accounting for 98.2 %). The increase in EGCG concentration from 10 to 100 μM resulted in a decreased formation of •OH yield and an enhanced generation of RO•. These findings highlight the capability of EGCG to improve the oxidation capacity of Fe(II)/PAA and modulate reactive species formation. The outstanding oxidation capacity and environmental friendliness of Fe(II)/EGCG/PAA process render it a potential strategy to eliminate organic pollutants in actual water treatment.

Progress in the Synthesis and Applications of C3N5-Based Catalysts in the Piezoelectric Catalytic Degradation of Organics

Piezoelectric catalysis has shown great potential for application in green chemistry due to its “clean” properties. By applying external mechanical force, this method can induce rapid charge transfer, providing an important reaction pathway for carbon neutrality and carbon peaking. Carbon nitride (C3N5)-based catalysts, as a novel material, have received widespread attention for their synthesis and application in the piezoelectric catalytic degradation of organic compounds. This review summarizes the latest research progress of C3N5-based catalysts, covering their applications in environmental governance and resource utilization, including the removal of organic pollutants in water. We focused on the synthesis strategy, characterization methods, and application progress of C3N5-based catalysts in the degradation of organic pollutants. The quantitative results show that some C3N5-based catalysts had removal efficiencies of over 85% in the treatment of specific pollutants. In addition, this article also discusses the piezoelectric effect and its degradation mechanism, providing direction for future research. Finally, the application prospects and potential development directions of C3N5-based catalysts in environmental governance are discussed.

Experimental and computational study of Bi2O3/WO3 heterostructures as efficient solar driven photocatalyst

Industrial wastewater is always a matter of challenge, polluting the environment and ultimately causing a hazardous effect on human beings and various other species. For the elimination of these pollutants, in this study, we synthesized Bi2O3 nanoparticles and Bi2O3/WO3 heterostructures by chemical co-precipitation method and investigated their photocatalytic activity for the degradation of methylene blue (MB) under solar light irradiation. The synthesized nanoparticles were characterized by various analytical techniques, including X-ray diffraction (XRD), Scanning-electron-microscopy (SEM), Fourier-Transform-Infrared Spectroscopy (FTIR), and UV–Vis. absorption Spectroscopy. Results of this study revealed that the pure Bi2O3 sample has a band gap of 3.5 eV, however, Bi2O3/WO3 heterostructure exhibited a reduction in band gap to 3.1 eV. The decrease in band gap significantly enhanced absorption of solar light, which correlated with an increase in photocatalytic activity as Bi2O3/WO3 nanocomposite degraded 81.5 % of MB in 240 min, while pristine Bi2O3 only degraded 58.7 % of the MB in the same period. The enhanced photocatalytic performance of the nanocomposite can be attributed to the synergistic action between Bi2O3 and WO3, which enhances the production of reactive oxygen species (ROSs) and the efficiency of charge separation, thus promoting the degradation of MB. A type-II heterostructure has been proposed to enhance the separation of charge carriers. Moreover, our computational study supported these findings, indicating a decrease in trends of the band gap of heterostructure as compared to pristine Bi2O3. The results of this study highlight the potential of Bi2O3/WO3 nanocomposites as promising materials for environmental remediation applications, particularly for the efficient removal of organic pollutants from wastewater under solar irradiation.

Rhodamine-B degradation, chromium removal and bactericidal potential of Cu–ZnO@ZrO2 nanoneedles fabricated via green route

Nanoparticles are being used for diverse environmental as well as biomedical applications due to their versatile features. In current work, a facile green synthesis route was employed for the fabrication of Cu–ZnO@ZrO2 nano-needles (NNs) using Momordica charantia (MC) stem extract and ZrO2 was used as a precursor along with CuCl2 and ZnCl2. UV–Vis and FTIR analysis confirmed the formation of Cu–ZnO@ZrO2 NNs. XRD studies confirmed orthorhombic geometry and FE-SEM images confirmed needle like structure of the prepared Cu–ZnO@ZrO2. Catalytic potential of the synthesized NNs was evaluated in terms of its efficiency towards degradation of rhodamine-B (Rh–B) dye. Degradation was achieved up to 98 % in 14 min in the presence of NNs. Conditions were optimized for the maximum removal of the dye using ascorbic acid (AA) as a reducing agent. Synthesized NNs sample was tested against another toxic pollutant i.e. Cr (VI) that was removed up to 65 % from aqueous medium. Promising antibacterial activity of the NNs was recorded against gram-positive and gram-negative bacterial strains. The results of the current study revealed promising features of NNs suggesting its use for the removal of microorganisms, organic and metallic pollutants. Authors would strongly suggest the fabrication of nanocomposites of same composition for the treatment of toxic pollutants in aqueous medium.

Synergistic Effects in MoS2/Co3O4/Cu2O Nanocomposites for Superior Solar Cell and Photodegradation Efficiency

Herein, we synthesized a Cu2O and Co3O4 incorporation with MoS2 to produce MoS2/Co3O4/Cu2O nanocomposites by facile sonication assisted hydrothermal methods. The phase structure and elemental composition of MoS2/Co3O4/Cu2O nanocomposites were investigated using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) morphology studies confirm that MoS2/Co3O4 nanostructure self-assembles in a mixed nanosheet configuration after the introduction of Cu2O. The synthesized samples were used as new types of Pt-free counter electrodes (CE) for DSSCs. Among all, the DSSCs based on the MoS2/Co3O4/Cu2O CE yields a maximum power conversion efficiency of 3.68% (Jsc = 8.2mAcm-2, Voc = 0.71mV and FF = 0.629%) under the standard AM 1.5G illumination, which is 2.5 times higher than that of pure MoS2. To assess the photocatalytic activity, prepared samples were used to suppress methylene blue (MB) and rhodamine B (RhB) dye under UV-visible light irradiation. The MoS2/Co3O4/Cu2O nanocomposites had the highest photocatalytic degradation efficiency of all the samples. It increased degradation efficiency from 43% to 91% for MB dye after 100minutes, and from 47% to 92% for RhB dye after 90minutes. Scavengers test analysis proved that the superoxide radical (•O2-) play a major role in the MoS2/Co3O4/Cu2O photocatalytic system. After four consecutive photocatalytic cycles, the crystal structure and surface morphology of the MoS2/Co3O4/Cu2O nanocomposites used in the 4th cycle were more stable, and this was confirmed by SEM, EDAX and XRD studies. The broader significance of these findings provides a straightforward approach for synthesizing a low-cost and high-efficiency MoS2/Co3O4/Cu2O nanocomposite for CE in DSSC photovoltaic cells and facilitates organic pollutant removal through photocatalytic applications.

MOFs-based 0D-2D-3D nanoarchitectonics as catalytic converters for peroxymonosulfate activation

Peroxymonosulfate-based advanced oxidation processes (PMS-AOPs) are promising trend for degrading of toxic organic pollutants. In this work, the novel 0D-2D-3D nanoarchitectonics (sandwich structure) are fabricated as advanced catalysts for PMS-AOPs. The distinctive sandwich structure of ZIF-67-AG-CA allows for the complete exposure of the active sites of ZIF-67, which can effectively activate PMS to generate both radical and non-radical species for the degradation of organic pollutants. Furthermore, the nano-reactive sites are distributed uniformly in layers, which provides additional PMS adsorption sites and enhances the efficiency of the catalytic reaction. Consequently, ZIF-67-AG-CA was observed to exhibit an excellent performance in the removal of organic pollutants by activating PMS, achieving a 99% degradation of 4-NP in 60 min and demonstrating good cycling stability through cycling experiments. Furthermore, quenching experiments and EPR demonstrated that SO42− and O2− radicals were involved in a synergistic manner in the catalytic reaction process with 1O2 non-radicals during the catalytic process.

Fluorine-doped cobalt ferrite integrated into 2D MXene with extended solar spectrum response and boosted charge separation for the removal of recalcitrant organic pollutants

In investigating sustainable methodologies for removing recalcitrant organic pollutants from wastewater, visible-light-responsive photocatalysis has drawn considerable interest. Therefore, intentionally engineered photocatalysts with enhanced solar-light-absorption capacity and boosted charge carrier’s separation are highly demanded. In the present attempt, pure cobalt ferrite (CoFe2O4) and its fluorine-doped counterpart (F-CoFe2O4) were fabricated via co-precipitation. The fluorine-doped material was integrated into the 2D MXene to design the composite (F-CoFe2O4@MXene) by the ultrasonication method. The structure, surface morphology, chemical composition, and optical properties of the as-prepared catalysts were characterized by various techniques, including powder XRD, FTIR, SEM, EDS, UV–vis absorption, and photoluminescence spectroscopy. The photocatalytic potential was estimated by degrading crystal violet (CV) dye and benzoic acid (BA), which were selected as model pollutants. The composite material showcases significantly enhanced catalytic efficiency relative to the pure and doped materials. Under solar light exposure for 140 min, 91 % (0.0138 min−1) and 87 % (0.0133 min−1) of CV and BA degradation were achieved, respectively. The remarkable catalytic potential of the composite material corresponds to the fluorine doping and integration to the 2D MXene, which has enhanced its visible-light absorption and lowered the rapid recombination rate of the separated charges (e-/h+). Systematic studies, including reaction kinetics, dominating catalytic species in photodegradation, and stability of the catalyst, were followed through to disclose the photocatalytic potential of the designed F-CoFe2O4@MXene. Furthermore, the real-time applicability of the catalyst has been explored.

Mg/Si- and Ag-Doped Carbon-Based Media Rainwater Filtration System for Multiple Pollutants Removal.

In this study, the removal performances of a multi-pollutant elimination cartridge system (MPECS) composed of palm shell waste-based activated carbon (PSAC), magnesium (Mg)/silicon (Si)-doped PSAC (Mg/Si-PSAC), and silver (Ag)-doped PSAC (Ag-PSAC) for heavy metals, organic pollutants, and Escherichia coli were investigated. Mg/Si impregnation significantly improved heavy metal removal using PSAC by increasing the surface area and adding more sorption sites to the magnesium silicate nanolayer. Fixed-bed column experiments showed that the MPECS column outperformed PSAC and commercial activated carbon (DJAC), with a 1.5 to 2.0 times higher E. coli removal and a higher removal of organic pollutants and heavy metals. The MPECS column, with its disinfection ability and adsorption of heavy metals and organic matter, is a promising system for removing multiple pollutants from rainwater.

S-scheme QDs-sized photocatalyst fabricated through combination of TiO2-x with gray BiOCl for efficient removal of organic pollutants upon visible light

As a safe and environmentally friendly technology, photocatalysis has a promising application in removing various pollutants from water systems. Herein, novel S-scheme QDs-sized TiO2-x/gray BiOCl (TiO2-x/G-BiOCl) heterojunction photocatalysts were successfully fabricated via a simple strategy. Among the photocatalysts, TiO2-x/G-BiOCl (20 %) nanocomposite exhibited superior activity in the photocatalytic degradation of tetracycline) TC(, azithromycin (Azi), fuchsine (FS), and malachite green)MG) upon visible light, which was about 14.1, 24.8, 11.4, and 4.61 folds higher than TiO2-x, and 18.5, 14.1, 28.4, and 11.4 times greater than G-BiOCl, respectively. The excellent photocatalytic activity of TiO2-x/G-BiOCl (20 %) nanocomposite was attributed to the significant light-harvesting ability, diminished electron/hole pair recombination, and superior textural properties. Furthermore, the biocompatibility of the resulting solution following TC removal over the TiO2-x/G-BiOCl (20 %) sample was investigated by the growth of wheat seeds. More importantly, this study provided new insights for designing high-efficiency visible-light-triggered photocatalysts employing defect-rich materials.