Organic Contaminants In Wastewater Research Articles

Construction of mesoporous PdO/YVO4 p-n heterojunction wrinkled-nanosheets fostering electron transfer for boosted photocatalytic atrazine degradation under visible light

Heterogeneous photocatalysis is an environmentally friendly and sustainable process for water purification. Unluckily, the significant propensity for photo-induced charge carriers to recombine rapidly, as well as poor responsiveness to visible light, are substantial shortcomings in conventional semiconductor photocatalysis. In this study, a facile surfactant-mediated solvothermal process, along with an impregnation approach was applied to fabricate a series of PdO/YVO4 p-n heterostructures with diverse PdO contents for atrazine (AT) oxidation under visible light. Diverse characterization tools confirmed the homogeneous dispersion of PdO nanoparticles (NPs) on mesoporous YVO4 nanosheets, thereby forming p-n junctions and facilitating charge carriers' separation. Moreover, the fabricated p-n heterojunction materials exhibited enhanced photoabsorbance abilities. It was demonstrated that the inclusion of PdO NPs considerably enhanced the photocatalytic capability and performance of the YVO4 candidate under visible light. The complete atrazine decomposition was accomplished on 2.0 g/L of 0.6 wt% PdO/YVO4 with a remarkable rate constant of 52.51 × 10−3 min−1 which was ca. 25.6-folds more than that achieved on bare YVO4 (2.05 × 10−3 min−1), while maintaining a 98.0 % recycling rate. The p-n heterojunction photocatalyst constructed between PdO and YVO4 exhibited a key role in improving the photoharvesting capability and accelerating the separation of photo-produced carriers, generating highly reactive oxygen species to degrade AT effectively. All in all, this achievement proposes a new YVO4-based heterostructures that can effectively eliminate organic contaminants in wastewater and also presents novel ideas for designing other heterojunctions.

Engineered design of MnFe2O4/CoNiFe-LTH/g-C3N4 heterocatalyst for doxycycline degradation via Fenton oxidation process: Optimization and mechanism

The removal of organic contaminants from waterways is vital to the ecosystem. A novel MnFe2O4/CoNiFe-LTH/g-C3N4 catalyst was synthesized via self-assembly preparation and linked with H2O2 for the Fenton degradation of doxycycline (DXY). The MnFe2O4/CoNiFe-LTH/g-C3N4 was characterized using FTIR, XRD, XPS, VSM, SEM, GC-MS, and ICP-OES. Interestingly, the magnetically separable and high-stability catalyst achieved 89.11% DXY degradation, and 69.30% TOC removal efficiency within 60 and 120 min, respectively (at pH = 7.5, catalyst dosage= 0.01g, H2O2 = 400 ppm, T= 20 °C, and DXY concentration= 100 ppm). In addition, the synergistic effect of metal cations (Co, Ni, Fe, and Mn) triggered Fenton degradation through a continuous closed cycle of electrons. A pseudo-first-order kinetic model also fitted DXY degradation with MnFe2O4/CoNiFe-LTH/g-C3N4. Furthermore, the radical pathway mechanism was confirmed with XPS before and after degradation and with radical scavenging tests. The DXY degradation pathway was speculated by GC-MS analysis. Quantitative structure-activity relationship (QSAR) was applied to assess intermediates for developmental toxicity. The MnFe2O4/CoNiFe-LTH/g-C3N4 catalytic activity on H2O2 decomposition was determined via titrimetric analysis. Recycling tests and ICP-OES measurements were further used to investigate the catalyst's resilience and reusability. Besides, MnFe2O4/CoNiFe-LTH/g-C3N4 demonstrated a performance of 70% over eight catalytic degradation runs with minimal metal leaching. Eventually, MnFe2O4/CoNiFe-LTH/g-C3N4 is a viable catalyst for breaking down organic contaminants in wastewater.

Performance evaluation of a wet air oxidation reactor with external circulation for high-chemical oxygen demand wastewater treatment

The presence of high-concentration organic contaminants in wastewater poses considerable risks to the health of both humans and ecosystems. Wet air oxidation (WAO) is an attractive treatment option, but current dilution and retreatment processes do not align with economic and environmental principles. Here we report an external circulation wet oxidation treatment process that utilizes oxidizing liquids to reduce feed concentration. By coupling energy consumption model with computational fluid dynamics model, we explore the optimal parameters for an industrial external circulation reactor. A 90 kt/a external circulation wastewater treatment system has been established, achieving a 21.6% increase in chemical oxygen demand (COD) removal efficiency and a 34.8% reduction in energy consumption. These findings provide a promising pathway for the efficient, low-energy treatment of high-concentration organic wastewater while minimizing freshwater resource consumption.

Potential of hospital wastewater treatment using locally isolated Chlorella sp. LH2 from cocoon wastewater

Chlorella sp. is able to grow and transform inorganic and organic contaminants in wastewater to create biomass. In the present study, Chlorella sp. LH2 isolated from cocoon wastewater was able to thrive in hospital wastewater, then remove nutrients and eliminate E. coli ATCC 8739. The results indicated that optimal cultivation conditions of Chlorella sp. LH2 in hospital wastewater were pH of 8, light:dark cycle of 16:8 at 30oC. The inhibitory effect of chlorination on algae growth was accompanied with the chlorine concentration. BOD5:COD ratio of 0.77 indicated biodegradability of hospital wastewater. The untreated and treated wastewatee samples were collected to investigated the nutrient removal efficiency after 10 days. Untreated and treated results were192 ± 8.62 mg/l 23.91 ± 2.19 mg/l for BOD5; 245 ± 9.15 mg/l and 47.31 ± 5.71 mg/l for COD. The treated value met the required standards for hospital wastewater treatment. The removal efficiency total nitrogen and total phosphorus were 68.64% and 64.44% after 10 days, respectively. Elimination of E. coli ATCC 8739 after 7 days by Chlorella sp. LH2 was 88.92%. The results of this study suggest the nutrients and pathogens removal potential of Chlorella sp. LH2 in hospital wastewater for further practical applications.

Visible-light photocatalytic O2-to-H2O2 via nitrogen-graphene quantum dots-modified Bi2Fe4O9 for synchronizing the reduction of Cr(VI) and oxidation of organic contaminants: Kinetics, mechanism, and performance

Synergistic coexistence of toxic chromium and organic contaminants in wastewater has made treatments highly complicated. As solar-driven wastewater treatments become increasingly environmentally and economically attractive, a photocatalyst (denoted as N-GQDs/Bi2Fe4O9) is developed for photocatalytic reduction of Cr(VI) and simultaneous oxidation of organic contaminants in wastewater. Incorporating N-GQDs (as electron reservoir) into Bi2Fe4O9 modulates the band structure (from 2.40 to 2.24 eV), facilitating charge transfer and electron accumulation at N-GQDs. Due to the photo-Fenton synergistic reaction between N-GQDs/Bi2Fe4O9 photocatalysis process, N-GQDs/ Bi2Fe4O9 demonstrates excellent H2O2 generation (1.64 μM min−1) and H2O2 activation (0.0063 min−1) performance, leading to generation of more highly reactive species (i.e., OH radicals), achieving BPA removal of 99.9 % under visible-light irradiation for 100 min. Interestingly, the photo-Fenton synergistic reaction enhances the reduction of Cr(VI) (99.8 %), while the Fe(II) active sites on the N-GQDs/Bi2Fe4O9 can also promote the synchronized Cr(VI) reduction. Also, the accumulated electron around N-GQDs enhances redox cycles of Fe(II)/Fe(III) reactions to realize the sustainable photo-Fenton catalytic reaction. This new N-GQDs/Bi2Fe4O9 photocatalyst demonstrates the feasibility of concurrent reduction of toxic Cr(VI)-to-Cr(III) and oxidation of organic contaminants in wastewater with a simple process via nearly unlimited solar energy.

Cobalt single-atom catalyst tailored ceramic membrane for selective removal of emerging organic contaminants

Water reuse is an effective way to solve the issues of current wastewater increments and water resource scarcity. Ultrafiltration, a promising method for water reuse, has the characteristics of low energy consumption, easy operation, and high adaptability to coupling with other water treatment processes. However, emerging organic contaminants (EOCs) in municipal wastewater cannot be effectively intercepted by ultrafiltration, which poses significant challenges to the effluent quality and sustainability of ultrafiltration process. Here, we develop a cobalt single-atom catalyst-tailored ceramic membrane (Co1-NCNT-CM) in conjunction with an activated peroxymonosulfate (PMS) system, achieving excellent EOCs degradation and anti-fouling performance. An interfacial reaction mechanism effectively mitigates membrane fouling through a repulsive interaction with natural organic matter. The generation of singlet oxygen at the Co-N3-C active sites through a catalytic pathway (PMS→PMS∗→OH∗→O∗→OO∗→1O2) exhibits selective oxidation of phenols and sulfonamides, achieving >90% removal rates. Our findings elucidate a multi-layered functional architecture within the Co1-NCNT-CM/PMS system, responsible for its superior performance in organic decontamination and membrane maintenance during secondary effluent treatment. It highlights the power of integrating Co1-NCNT-CM/PMS systems in advanced wastewater treatment frameworks, specifically for targeted EOCs removal, heralding a new direction for sustainable water management.

Al/Ca-doped CuFe2O4 prepared from waste printed circuit boards as a magnetic peroxymonosulfate activator for the degradation of organic pollutants

Cu-containing heterogeneous catalysts are being increasingly used to activate peroxymonosulfate (PMS) and remove organic pollutants from wastewater. However, expensive raw materials and limited metal resources restrict the practical applications of these catalysts. In this study, waste printed circuit boards (PCBs), a typical Cu-rich electronic waste, were used to prepare Al/Ca-doped CuFe2O4 (PCBs-CuFe2O4) with the assistance of Fe3+. The obtained PCBs-CuFe2O4, doped with the catalytically inert metals Al and Ca, possessed abundant porous structures, high specific surface areas, rich surface oxygen vacancies, and excellent magnetic properties. Despite its relatively poor purity and crystallinity compared to those of CuFe2O4 prepared using commercial chemicals, PCBs-CuFe2O4 exhibited superior performance in reactive blue 19 (RB19) degradation by activating PMS. Additionally, the PCBs-CuFe2O4/PMS system exhibited strong resistance to pH and water matrices, confirming the practical application of PCBs-CuFe2O4 for the elimination of organic pollutants in wastewater. Furthermore, the results of electrochemical measurements, quenching experiments, and electron paramagnetic resonance analysis revealed that 1O2 plays an important role in the degradation of RB19. The Cu(I)/Cu(II), Fe(II)/Fe(III), and OV of PCBs-CuFe2O4 dominate the activation of PMS. Thus, this study presents a novel strategy for reutilizing waste PCBs and eliminating organic contaminants in wastewater.

Interface engineering of 1D/2D FeVO4/MoS2 hetero-structured nanocomposite with effective interfacial charge transfer: Facile synthesis and antibiotic drug degradation

The rapid accumulation of organic contaminants in wastewater is a considerable environmental concern. We are investigating nanoscale FeVO4 and MoS2 structures for enhanced removal of organic pollutants to overcome this challenge. The FeVO4/MoS2 nanocomposite was synthesized via a hydrothermal technique. This study looks at how the FeVO4/MoS2 nanocomposite could be explored as a good catalyst for the degradation of ciprofloxacin drug through Photo-Fenton process. The synergy between FeVO4 and MoS2 and hydroxyl radicals leads to accelerated degradation. Our findings imply that FeVO4/MoS2 nanocomposites could remove pharmaceutical pollutants from wastewater sources, contributing to water treatment technology.

Adsorption Capacity of Carbon-Silica Composites Towards Diclofenac in Poly(acrylic acid) Containing Systems: A Crucial Study on Common Wastewater Contaminants.

Diclofenac is one of the most popular over-the-counter non-steroidal anti-inflammatory drug and poly(acrylic acid) is a frequently used as thickener, filler or stabilizer. For these reasons, they are common organic contaminants in raw wastewater. The purpose of the presented studies was to compare the adsorption capacity of three carbon-silica composites - metal-free C/SiO2 , iron-enriched C/Fe/SiO2 and manganese-enriched C/Mn/SiO2 towards diclofenac. The studies were carried out in single, and mixed systems in the presence of poly(acrylic acid) polymer. Adsorption, desorption and kinetics of the adsorption process were investigated. The concentration of diclofenac in the supernatants was determined using high-performance liquid chromatography. The solids were also characterized with an ASAP apparatus using low-temperature nitrogen desorption adsorption isotherms at liquid nitrogen temperature. In addition, potentiometric titrations and electrophoretic mobility measurements, as well as stability tests of the studied suspensions were carried out. The most efficient composite among investigated ones proved to be C/Fe/SiO2 removing diclofenac at the level of 46.68 mg/g for its initial concentration of 90 ppm. The results obtained clearly demonstrated that the carbon-silica composites are effective in separation of drugs from aqueous solutions and can be successfully used in the future for the removal of organic pollutants from water environment.

Tunning MIL-101(Cr) MOF polymorphism towards efficient adsorption and localized Fenton-like degradation of para-nitroaniline by Fe incorporation

The employment of metal–organic frameworks (MOFs) in the context of eliminating organic contaminants from water has garnered significant interest in contemporary research. This study investigated the impact of varying quantities of iron on the MIL-101(Cr) adsorbent. For the first time, a polymorphic Cr/Fe-MOF was utilized for the adsorption and localized Fenton-like degradation of p-nitroaniline (PNA). Importantly, the Fe centers exhibited a ternary role of (i) transforming MIL-101 into MIL-53lt morphology, (ii) boosting PNA adsorption on the MIL(Cr) material, and (iii) enabling the Fenton-like decomposition of the adsorbed PNA in reduced solution volume. Cr:Fe(50:50) exhibited the highest adsorption capacity of 378.9 mg/g, notwithstanding its smaller surface area (SBET = 8.9 m2/g). Overall, adsorption kinetics and isotherms correlated better with pseudo-second-order and Langmuir models, respectively. The adsorption mechanism was attributed to breathing effect, H-bonding and π-π interaction. Besides, PNA degradation kinetics stood at 0.21 min−1, and the reactive oxygen species were identified as •OH, •O2– and 1O2. During continuous removal of PNA, the Cr:Fe(50:50) MOF immobilized onto cotton met the environmental discharge standard (1 mg/L) up to 52 bed volumes (initial P = 10.0 mg/L at 1 mL/min). This study not only presents a superior polymorphic MOF adsorbent but also promotes the fabrication of localized Fenton-like catalysts for the removal of organic contaminants in wastewater.

Progress in the Elimination of Organic Contaminants in Wastewater by Activation Persulfate over Iron-Based Metal-Organic Frameworks.

The release of organic contaminants has grown to be a major environmental concern and a threat to the ecology of water bodies. Persulfate-based Advanced Oxidation Technology (PAOT) is effective at eliminating hazardous pollutants and has an extensive spectrum of applications. Iron-based metal-organic frameworks (Fe-MOFs) and their derivatives have exhibited great advantages in activating persulfate for wastewater treatment. In this article, we provide a comprehensive review of recent research progress on the significant potential of Fe-MOFs for removing antibiotics, organic dyes, phenols, and other contaminants from aqueous environments. Firstly, multiple approaches for preparing Fe-MOFs, including the MIL and ZIF series were introduced. Subsequently, removal performance of pollutants such as antibiotics of sulfonamides and tetracyclines (TC), organic dyes of rhodamine B (RhB) and acid orange 7 (AO7), phenols of phenol and bisphenol A (BPA) by various Fe-MOFs was compared. Finally, different degradation mechanisms, encompassing free radical degradation pathways and non-free radical degradation pathways were elucidated. This review explores the synthesis methods of Fe-MOFs and their application in removing organic pollutants from water bodies, providing insights for further refining the preparation of Fe-MOFs.

High Tribocatalytic Performance of FeOOH Nanorods for Degrading Organic Dyes and Antibiotics.

Tribocatalysis is vitally important for electrochemistry, energy conservation, and water treatment. Exploring eco-friendly and low-cost tribocatalysts with high performance is crucial for practical applications. Here, the highly efficient tribocatalytic performance of FeOOH nanorods is reported. The factors related to the tribocatalytic activity such as nanorod diameter, surface area, and surface roughness are investigated, and the diameter of the FeOOH nanorods is found to have a significant effect on their tribocatalytic performance. As a result, under ultrasonic excitation, the optimized FeOOH nanorods exhibit superior tribocatalytic degradation toward rhodamine B (RhB), acid orange 7, methylene blue, methyl orange dyes, and their mixture. The RhB and mixed dyes are effectively degraded within 20min (k = 0.179 min-1 ) and 35min (k = 0.089 min-1 ), respectively, with the FeOOH nanorods showing excellent reusability. Moreover, antibiotics, such as tetracycline hydrochloride, phenol, and bisphenol A are efficiently degraded. Investigation of the catalytic mechanism reveals that the friction-generated h+ as well as these yielded •OH and •O2 - active radicals participate in the catalytic reaction. This work not only shed light on the design of high-performance tribocatalyst but also demonstrates that by harvesting mechanical energy, the FeOOH nanorods are promising materials for removing organic contaminants in wastewater.

Flow cytometric assessments of metabolic activity in bacterial assemblages provide insight into ecosystem condition along the Buffalo National River, Arkansas

The Buffalo National River (BNR), on karst terrain in Arkansas, is considered an extraordinary water resource. Water collected in Spring 2017 along BNR was metagenomically analyzed using 16S rDNA, and for 17 months (5/2017–11/2018), bacterial responses were measured in relation to nutrients sampled along a stretch of BNR near a concentrated animal feed operation (CAFO) on Big Creek. Because cell count and esterase activity can increase proportionally with organic enrichment, they were hypothesized to be elevated near the CAFO. Counts (colony forming units; CFUs) were different among sites for 73 % of the months; Big Creek generated highest CFUs 27 % of the time, with the closest downstream site at 13.3 %. Esterase activity was different among sites 94 % of the time, with Big Creek exhibiting lowest activity 71 % of the time. Over the months, activity was similar across sites at ~70 % active, except at Big Creek (56 %). The α-diversity of BNR microbial consortia near a wastewater treatment plant (WWTP) and the CAFO was related to distance from the WWTP and CAFO. The inverse relationship between high CFUs and low esterase activity at Big Creek (r = −0.71) actuated in vitro exposures of bacteria to organic wastewater contaminants (OWC) previously identified in the watershed. Exponential-phase Escherichia coli (stock strain), Streptococcus suis (avirulent, from swine), and S. dysgalactiae (virulent, from silver carp, Hypophthalmichthys molitrix) were incubated with atrazine, pharmaceuticals (17 α-ethynylestradiol and trenbolone), and antimicrobials (tylosin and butylparaben). Bacteria were differentially responsive. Activity varied with exposure time and OWC type, but not concentration; atrazine decreased it most. Taken together - the metagenomic taxonomic similarities along BNR, slightly higher bacterial growth and lower bacterial esterase at the CAFO, and the lab exposures of bacterial strains showing that OWC altered metabolism - the results indicated that bioactive OWC entering the watershed can strongly influence microbial processes in the aquatic ecosystem.

Integrated Ozonation Ni-NiO/Carbon/g-C3N4 Nanocomposite-Mediated Catalytic Decomposition of Organic Contaminants in Wastewater under Visible Light.

Developing a hybrid process for wastewater purification is of utmost importance to make conventional methods more efficient and faster. Herein, an effective visible light-active nickel-nickel oxide/carbon/graphitic carbon nitride (Ni-NiO/C/g-C3N4)-based nanocatalyst was developed. A hybrid process based on ozonation and Ni-NiO/C/g-C3N4 visible light photocatalysis was applied to decolourize the Congo red (CR), Alizarin Red S (ARS), and real dairy industry wastewater. The synthesized catalyst was characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Χ-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectrophotometry (UV-Vis DRS). The factors affecting the catalytic process were evaluated, including contact time, solution pH, initial dye concentration, etc. The degradation rate of CR and ARS was compared between the photocatalysis, ozonation, and integrated photocatalytic ozonation (PC/O3) methods. The results showed 100% degradation of CR and ARS within 5 min and 40 min, respectively, by integrated PC/O3. The reusability of the modified catalyst was evaluated, and four successive regenerations were achieved. The modified Ni-NiO/C/g-C3N4 composite could be considered an effective, fast, and reusable catalyst in an integrated PC/O3 process for the complete decolourization of wastewater.

Fe-doped g-C3N4 with duel active sites for ultrafast degradation of organic pollutants via visible-light-driven photo-Fenton reaction: Insight into the performance, kinetics, and mechanism

The photo-Fenton process provides a sustainable and cost-effective strategy for removing refractory organic contaminants in wastewater. Herein, a high-efficient Fe-doped g-C3N4 photocatalyst (Fe@CN10) with a unique 3D porous mesh structure was prepared by one-pot thermal polymerization for ultrafast degradation of azo dyes, antibiotics, and phenolic acids in heterogeneous photo-Fenton systems under visible light irradiation. Fe@CN10 exhibited a synergy between adsorption-degradation processes due to the co-existence of Fe3C and Fe3N active sites. Specifically, Fe3C acted as an adsorption site for pollutant and H2O2 molecules, while Fe3N acted as a photocatalytic active site for the high-efficient degradation of MO. Resultingly, Fe@CN10 showed a photocatalytic degradation rate of MO up to 140.32 mg/L min−1. The dominant ROS contributed to the removal of MO in the photo-Fenton pathway was hydroxyl radical (•OH). Surprisingly, as the key reactive species, singlet oxygen (1O2) generated from superoxide radical (•O2−) also efficiently attacked MO in a photo-self-Fenton pathway. Additionally, sponge/Fe@CN10 was prepared and filled in the continuous flow reactors for nearly 100% degradation of MO over 150 h when treating artificial organic wastewater. This work provided a facile route to prepare highly-active Fe-doped photocatalysts and develop a green photocatalytic system for wastewater treatment in the future.

Re-utilization of drinking water treatment residuals (DWTR): a review focused on the adsorption of inorganic and organic contaminants in wastewater and soil

Drinking water treatment residuals (DWTRs) show versatile adsorption properties for the removal of contaminants from wastewater and soil. Most adsorption studies are based on synthetic well-controlled solutions instead of real wastewater samples.

Linker regulation of CoO@Cu/C derived from self-assembly of MOF to enhance catalytic activity of organic contaminants

The reduction of hazardous organic contaminants in agricultural wastewater to their corresponding amines is a key procedure in the fine chemical industry for pharmaceuticals, polymers, agrochemicals, and dyes. However, their effective and selective reduction reactions require compressed hydrogen at high temperatures, which are expensive and limited in supply. In this study, we present a novel approach using a layer-by-layer (LBL) assembly of copper metal–organic frameworks (MOFs) to prepare an earth-abundant, highly stable plasmonic nano-photocatalyst (i.e., Cu nanoparticles (NPs)) over Co3O4 nanocubes (indicated as CoO@Cu/C). The catalyst was produced by thermally treating the prepared core–shell material. Herein, highly monodispersed Cu NPs with an average size of 5 nm were embedded in the carbon shell on the surface of CoO. This unique composition resulted in a significant enhancement in the catalytic performance, yielding a remarkable efficiency (≈100 % after 60 s) and exceptional selectivity (≈98 %). Consequently, the reusable and sustainable CoO@Cu/C catalyst exhibited brings unattainable a remarkable catalytic performance and consistent activity even after six cycles in water owing to this unique composition of the homogeneously dispersed Cu-NPs inside the carbon shell. This, in turn, resulted in highly effective adsorption characteristics of the carbon matrix and high catalytic performance of ultra-small Cu-NPs on the CoO surface. Moreover, the activity of this catalyst is highly effective. This study presents an effective strategy for obtaining remarkable catalytic performance and selectivity via the coordination activation of Cu-NPs on the CoO surface.

Solid state conversion of novel coordinated precursors to visible light active photocatalysts with enhanced photocatalytic activity

The new polydentate N'1,N'3‐bis((E)‐3‐oxopentan‐2‐ylidene)malonohidrazide chelating agent (H2L) and its coordinated complexes of Co2+, Cu2+, and Ni2+ were prepared and characterized by elemental analysis, molar conductance, and spectra (Fourier transform infrared [FT‐IR], ultraviolet–visible spectroscopy [UV–vis], and Fast‐Atom Bombardment Mass Spectrometry (FAB‐MS). Also, thermal and magnetic investigations were conducted. X‐ray single crystal of the H2L ligand revealed a triclinic structure with space group P‐1. In this study, we provide a one‐pot preparation approach for transition metal oxide nanoparticles (NPs) such as CuO, Co3O4, and NiO NPs. The methodology entails the thermal decomposition of coordinated metal precursors in a solid‐state environment, obviating the necessity for agitation and rinsing. The remarkable significance of this method lies in its ability to produce highly pure NPs without the requirement of washing, and it allows for systematic and efficient production. Herein, we propose a large‐scale, environmentally benign and renewable, transition metals oxide NPs such as CuO, Co3O4, and NiO using solid‐state thermal degradation of their coordinated precursors. The NPs are subjected to analysis employing a range of techniques, such as X‐ray powder diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), N2 sorpometry (BET), and UV–vis). The photocatalytic activities of the synthesized NPs were assessed using photodegradation of organic contaminants in wastewater.

Mxene-based ceramic nanofiltration membranes for selective separation of primary contaminants in semiconductor wastewater

Ceramic membranes, known for their exceptional chemical stability, have found practical applications in the treatment of semiconductor wastewater. In this study, we have developed an innovative ceramic nanofiltration membrane featuring a nanochannel network created by two-dimensional (2D) nanomaterials, enabling high-performance separation and permeation. This accomplishment is realized through precise control of the size and thickness of MXene nanomaterials, which can be tailored using various coating conditions. The repeated stacking of MXene nanosheets onto the ceramic membrane substrate resulted in the formation of additional nanochannels and surface chemistry modifications, leading to significant enhancements in pollutant removal. These MXene-coated ceramic nanofiltration (NF) membranes significantly improved the removal efficiency of representative organic contaminants in semiconductor wastewater when compared to the pristine ceramic membrane. It enhanced the removal efficiencies by 4.2 times for dissolved silica, 3.7 times for dimethyl sulfoxide (DMSO), and 2.5 times for isopropyl alcohol (IPA). Furthermore, the MXene ceramic NF membrane exhibited exceptional fluoride removal capability, achieving approximately 99.1% removal, in addition to organic solvents. These findings not only help meet regulatory standards for wastewater discharge but also provide valuable insights into the transport behaviors of contaminants and their separation mechanisms. This innovative approach brings us one step closer to efficient and sustainable solutions for semiconductor wastewater treatment.

Interfacial modulation of α-Ag1.82Cu0.09WO4 with high active BiOClxI1−x for boosting photocatalytic activity and degradation of emerging contaminants under direct sunlight

Removal of organic contaminants in wastewater using sunlight-driven photocatalysts has received significant attention in recent years. However, the rational design of photocatalysts to attain high light absorption, lower charge carrier recombination with efficient photocatalytic activity and good recycling capability is crucial for the practical photocatalysis process. Herein, solid-state Z-scheme BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 heterojunction is synthesized by assembling hierarchical 3D-BiOCl0.6I0.4 nanoflowers on cube-like 3D-α-Ag1.82Cu0.09WO4 surface through a hydrothermal method. A wide range of characterization techniques confirms the successful synthesis of BiOClxI1−x (0 ≤ x ≤ 1.0), α-Ag1.82Cu0.09WO4 and BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 binary composites. The TC antibiotic removal efficiency of 30 wt% BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 binary composite reaches 95.91% within 120 min under natural sunlight irradiation and the rate constant is 1.81 and 3.33 times higher than the pristine BiOCl0.6I0.4 and α-Ag1.82Cu0.09WO4, respectively. The optimized binary heterojunction exhibits excellent photocatalytic performance for toxic pollutants like MB (η = 97.27%) and RhB (η = 95.75%) under direct sunlight irradiation. The favorable photocatalytic activity of binary heterojunction is ascribed to enhancing the sunlight absorption range, the tight contact interface and the effective separation of electron/hole pairs. Notably, 30 wt% BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 binary composite exhibits attractive recycling ability and good photostability for prolonged sunlight irradiation. Furthermore, the total organic carbon results also confirm that the 30 wt% BiOCl0.6I0.4/α-Ag1.82Cu0.09WO4 efficiently mineralized the model pollutants (TC antibiotic, MB and RhB) into other unharmful compounds under sunlight irradiation. In summary, this work offers an effective strategy to prepare solid-state Z-scheme heterojunction with favorable photocatalytic activity, which can increase wastewater purification efficiency.