Reduction Of Degradation Research Articles

Novel S-scheme Bi24O31Cl10/Bi7Fe2Ti2O17Cl heterojunction for efficient and stable photocatalytic activities

The strategy to boost photocatalytic activities toward CO2 reduction and organic pollutants degradation is still a key challenge for novel Sillén–Aurivillius oxyhalides. In this work, an S-scheme heterojunction of Bi24O31Cl10 and Bi7Fe2Ti2O17Cl is designed for CO2 reduction and organic pollutants degradation. The as-synthesized 5 % Bi24O31Cl10/Bi7Fe2Ti2O17Cl (BOC/BFTOC-5) composites depict an appealing CO2 reduction and removal rate for RhB organic pollutants in comparison with pristine Bi24O31Cl10 and Bi7Fe2Ti2O17Cl oxyhalides. This fascinating photocatalytic performance could be ascribed to the synergic effect of the enhanced visible light adsorption and photo-generated carriers separation derived from the Bi24O31Cl10/Bi7Fe2Ti2O17Cl heterojunction. Simultaneously, the trapping experiments confirm that the main active species during the catalytic process are the photo-generated hole (h+) and the hydroxy free radical (·OH). This work aims at providing an S-scheme heterojunction via Bi-based oxyhalides for efficient photocatalytic activity.

Changes in soil properties of xerophytic forests in Southern Russia after anthropogenic impact

Anthropogenic influences negatively affect the soil properties and woody vegetation in the xerophytic forests and the rare forests of the northern coastal area of the Black Sea. The study was carried out at the properties of soils in the Utrish State Nature Reserve (Russia), which was previously under the influence of anthropogenic impact. Fires, deforestation, and recreational load were selected as the prioritised types of anthropogenic impact in long-term studies with soil (Cambisols) in the Utrish State Nature Reserve, which rapidly lead to the degradation of ecosystems and biodiversity reduction. Soil samples were taken from the 0–10-cm layer in triplicate from each study site. The study site after recreational load has been investigated in 2013, 2015, 2018, 2019, and 2020. The parameters pH, organic carbon content, enzyme activity were studied. Biological properties of soils were found to be more sensitive to changes in characteristics than other soil parameters. For all the studied parameters, there was a decrease in the organic carbon content from 18% to 59% relative to the control. The highest decrease in the indicator was noted for soils after deforestation. Enzymes from the oxidase class recover faster than the hydrolases. Catalase activity for all disturbed soils decreased on average by 13%. Non-significant differences from the control were observed for soils after deforestation and fires. Inhibition of invertase activity was established in soils by an average of 52% after fires and recreational exposure, with an increase in enzyme activity of 77% observed after deforestation. The results can be used to assess effects of the anthropogenic impacts on forests. Biological indicators are good markers of the condition of disturbed soils that could be implicated to determine the prioritised anthropogenic load in the soils of xerophytic forests.

High-entropy-based nano-materials for sustainable environmental applications.

High entropy materials (HEMs), epitomized by high entropy alloys (HEAs), have sparked immense interest for a range of clean energy and environmental applications due to their remarkable structural versatility and adjustable characteristics. In the face of environmental challenges, HEMs have emerged as valuable tools for addressing issues ranging from wastewater remediation to energy conversion and storage. This review provides a comprehensive exploration of HEMs, spotlighting their catalytic capabilities in diverse redox reactions, such as carbon dioxide reduction to value-added products, degradation of organic pollutants, oxygen reduction, hydrogen evolution, and ammonia decomposition using electrocatalytic and photocatalytic pathways. Additionally, the review highlights HEMs as novel electrode nanomaterials, with the potential to enhance the performance of batteries and supercapacitors. Their unique features, including high capacitance, electrical conductivity, and thermal stability, make them valuable components for meeting crucial energy demands. Furthermore, the review examines challenges and opportunities in advancing HEMs, emphasizing the importance of understanding the underlying mechanisms governing their catalytic and electrochemical behaviors. Essential considerations for optimizing the HEM performance in catalysis and energy storage are outlined to guide future research. Moreover, to provide a comprehensive understanding of the current research landscape, a meticulous bibliometric analysis is presented, offering insights into the trends, focal points, and emerging directions within the realm of HEMs, particularly in addressing environmental concerns.

Exploring the Remarkably High Photocatalytic Efficiency of Ultra-Thin Porous Graphitic Carbon Nitride Nanosheets.

Graphitic carbon nitride (g-C3N4) is a metal-free photocatalyst used for visible-driven hydrogen production, CO2 reduction, and organic pollutant degradation. In addition to the most attractive feature of visible photoactivity, its other benefits include thermal and photochemical stability, cost-effectiveness, and simple and easy-scale-up synthesis. However, its performance is still limited due to its low absorption at longer wavelengths in the visible range, and high charge recombination. In addition, the exfoliated nanosheets easily aggregate, causing the reduction in specific surface area, and thus its photoactivity. Herein, we propose the use of ultra-thin porous g-C3N4 nanosheets to overcome these limitations and improve its photocatalytic performance. Through the optimization of a novel multi-step synthetic protocol, based on an initial thermal treatment, the use of nitric acid (HNO3), and an ultrasonication step, we were able to obtain very thin and well-tuned material that yielded exceptional photodegradation performance of methyl orange (MO) under visible light irradiation, without the need for any co-catalyst. About 96% of MO was degraded in as short as 30 min, achieving a normalized apparent reaction rate constant (k) of 1.1 × 10-2 min-1mg-1. This represents the highest k value ever reported using C3N4-based photocatalysts for MO degradation, based on our thorough literature search. Ultrasonication in acid not only prevents agglomeration of g-C3N4 nanosheets but also tunes pore size distribution and plays a key role in this achievement. We also studied their performance in a photocatalytic hydrogen evolution reaction (HER), achieving a production of 1842 µmol h-1 g-1. Through a profound analysis of all the samples' structure, morphology, and optical properties, we provide physical insight into the improved performance of our optimized porous g-C3N4 sample for both photocatalytic reactions. This research may serve as a guide for improving the photocatalytic activity of porous two-dimensional (2D) semiconductors under visible light irradiation.

Fabrication of site activated and synergistic double vacancy ZnIn2S4 for highly efficient bifunctional photocatalysis: nitrogen reduction and oxidative degradation

A novel methodology harnessing the synergistic influence of bimetallic and non-metallic dual vacancies within a unified catalyst for enabling highly efficient bifunctional photocatalysis encompassing oxidation and reduction processes is presented.

Pure and Cobalt-Modified ZnO Nanostructures Prepared by a New Synthesis Route Applied to Environmental Remediation

Pure and cobalt-doped 3D ZnO were produced using the microwave (MW)- ultraviolet (UV)-visible (Vis) radiation-assisted hydrothermal method (MW-UV-Vis HM). Using experimental design, the effects of cobalt and UV-Vis radiation during the synthesis stage on the physicochemical properties of the materials were evaluated with different characterization techniques such as X-ray diffraction, scanning and transmission electron microscopy, diffuse reflectance, and electrochemistry. The presence of cobalt had a great influence on the reduction of charge donors in the ZnO matrix and had their photocatalytic properties improved when produced under the effect of UV-Vis radiation. The catalytic activity of the materials has been verified in important environmental remediation reactions, such as the electrochemical reduction of CO2 and the photocatalytic degradation of emerging pollutants. The results achieved in this study show competitive efficiency values for CO2 reduction (97%) and photocatalytic degradation (91%) of emerging pollutants in natural waters, illustrating the great versatility of the produced material in distinct applications.

Construction and mechanism insights of a novel all-solid-state Z-scheme Mo2C/C/BiOI heterojunction for boosted photocatalytic degradation and reduction efficiency

Interfacial configuration of heterostructured photocatalysts to boost photocarrier separation and transfer is immensely beneficial to acquire great photocatalytic efficiency. Herein, a well-structured Mo2C/C/BiOI heterostructure containing different weight ratios Mo2C instead of noble metal was successfully prepared, where the inter-modified carbon nanosheets subserve as a connective to generate a perfect interface contact between Mo2C and BiOI. The photocatalytic performances of the photocatalysts were appraised by the degradation of indigo carmine and reduction of 4-nitroaniline under visible-light elucidation. The nanocomposite containing 7 % by weight of Mo2C/C showed the highest photocatalytic efficiency by eliminating 99.4 % of indigo carmine and 99.8 % of 4-nitroaniline within 75 min and 13 min, respectively. The boosted photocatalytic activity is attributed to the synergistic interaction between Mo2C/C and BiOI and the all-solid-state Z mechanism, where conductive carbon nanoparticles as an efficient electron mediator enable rapid photocarrier transfer and separation between Mo2C and BiOI. This study accentuates that Mo2C/C-based all-solid-state Z-scheme heterojunction nanocomposites are hopeful candidate photocatalysts for environmental applications.

High-efficient charge separation in novel Zn0.5Cd0.5S/Bi4V2O11 heterostructure for boosting photocatalytic Cr (VI) reduction and degradation of tetracycline hydrochloride

Photocatalysis is a green and sustainable technology for the efficient removal of harmful pollutants in water, however, due to the coexistence of multiple pollutants in water system, it is a great challenge to develop multi-functional and efficient photocatalytic systems. Herein, a novel bifunctional Zn0.5Cd0.5S/Bi4V2O11 (ZCS/BVO) heterostructrue photocatalyst was designed and prepared by growing Zn0.5Cd0.5S nanospheres on the surfaces of Bi4V2O11 disc-like nanoflowers through a facial in-situ hydrothermal method. The as-prepared ZCS/BVO heterostructure showed much more enhanced bifunctional visible-light catalytic activity for Cr (VI) reduction and TCH degradation compared with pure Zn0.5Cd0.5S and Bi4V2O11. Among ZCS/BVO samples, ZCS/BVO-10 possessed the best Cr (VI) reduction performance of 86.7 % in 60 min, which was 1.38 and 9.96 times of Zn0.5Cd0.5S and Bi4V2O11. Moreover, ZCS/BVO-10 heterostructure also showed excellent TCH degradation ability of 80.3 % in 48 min, about 2.38 and 3.20 times as high as those of Zn0.5Cd0.5S and Bi4V2O11. The synergistic effect between Zn0.5Cd0.5S and Bi4V2O11 and the close contacted ZCS/BVO heterostructure greatly favored TCH degradation and Cr (VI) reduction reactions due to the increased surface area, enhanced light absorption and boosted charge separation. From the cyclic experiment, ZCS/BVO exhibited high stability and reusability. This work undoubtedly provided a multi-functional and effective photocatalyst for treating various pollutants in water bodies.

Rapid and effective removal of copper, nitrate and trichloromethane from aqueous media by aluminium alloys

Zero-valent iron (ZVI) has been extensively studied for its efficacy in removing heavy metals, nitrate, and chlorinated organic compounds from contaminated water. However, its limited effectiveness due to rapid passivation and poor selectivity is prompting for alternative solutions, such as the use of aluminium alloys. In this study, the efficacy of five distinct aluminium alloys, namely Al–Mg, Al–Fe, Al–Cu, and Al–Ni, each comprising 50 % Al by mass at a concentration of 10 g/L, was assessed using copper, nitrate and trichloromethane (TCM) as model contaminants. Results show that chemical pollutants reacted immediately with Al–Mg. On the contrary, the remaining three alloys exhibited a delay of 24 h before demonstrating significant reactivity. Remarkably, Al–Mg alloy reduced nitrate exclusively to ammonium, indicating minimal preference for nitrate reduction to N2. In contrast, the Al–Cu, Al–Ni, and Al–Fe alloys exhibited N2 selectivity of 3 %, 5 %, and 19 %, respectively. The removal efficiency of copper, nitrate and TCM reached 99 % within 24 h, 95 % within 48h and 48 % within 48h, respectively. Noteworthy findings included the correlation between Fe concentration within the Al–Fe alloy and an increased N2 selectivity from 9.3 % to 24.1 %. This resulted in an increase of Fe concentration from 10 % to 58 % albeit with a concurrent reduction in reactivity. Cu2+ removal by Al–Fe alloy occurred via direct electron transfer, while the removal of nitrate and TCM was facilitated by atomic hydrogen generated by the alloy's hydrolysis. Intriguingly, nitrate and TCM suppressed Cu2+ reduction, whereas Cu2+ improved nitrate reduction and TCM degradation. These findings demonstrate the great potential of Al–Mg and Al–Fe alloys as highly efficient agents for water remediation.

Advances in S-scheme heterojunction semiconductor photocatalysts for CO2 reduction, nitrogen fixation and NOx degradation

Advances in S-scheme heterojunction semiconductor photocatalysts for CO2 reduction, nitrogen fixation and NOx degradation

CO2 Photoreduction Activity Enhancement and Unexpected Observation of Carbon Monoxide Adsorbates on the Surface of TiO2 Nanotube Arrays Synthesized in Formamide Electrolytes.

TiO2 nanotube arrays grown through electrochemical anodization in a formamide-based electrolyte (TNTA-FA) exhibited a whole host of unusual properties compared to nanotubes grown in the conventional ethylene glycol-based electrolyte (TNTA-EG). TNTA-FA exhibited shorter phonon lifetimes, lower lattice strain, more visible light absorption, lower work function, and a highly unusual adsorbate structure consisting of physisorbed and chemisorbed CO along with linearly adsorbed CO2 and various monodentate and bidentate carbonate species. The observation of adsorbed CO in the dark is highly unusual and indicates spontaneous deoxygenation of CO2 on the surface of TNTA-FA. The significance of this finding is that the formation of CO2•- is no longer the rate-limiting bottleneck for the reduction of CO2 on TNTA-FA surfaces as it is for all TiO2 surfaces. TNTA-FA samples are strongly colored (inclusive of a fluorescent green color) and consist of rounded, vertically oriented hollow cylinders as opposed to the honeycomb-like morphology of TNTA-EG arranged in an approximate triangular lattice. The photocatalytic activity was tested through the CO2 photoreduction and dye degradation tests. Formamide-based nanotubes outperformed the EG-based nanotubes by almost 1.7 and 2 times, respectively, in CO2 reduction and dye degradation tests done on methylene blue, brilliant green, and rhodamine B dyes. These results are attributed to stronger surface band bending in TNTA-FA which facilitates more efficient separation of photogenerated electron-hole pairs.

REM-422, a Potent, Selective, Oral Small Molecule mRNA Degrader of the MYB Oncogene, Demonstrates Anti-Tumor Activity in Mouse Xenograft Models of AML

The c-MYB (MYB) oncogenic transcription factor is a key regulator of hematopoietic cell differentiation and proliferation. Recurrent genetic lesions or dysregulation of MYB have been identified in a variety of cancers, including adenoid cystic carcinoma (ACC), acute myeloid leukemia (AML), T-cell acute lymphoblastic leukemia (T-ALL), blastic plasmacytoid dendritic cell neoplasm (BPDCN), pediatric low-grade glioma (pLGG), and others. AML is characterized by multiple oncogenic abnormalities and high MYB mRNA expression. Evidence from in vitro and in vivo animal studies suggests that MYB may be a key downstream effector of these oncogenic abnormalities through the direct regulation of genes such as BCL2, MYC and FLT3. Functional genomics studies reveal MYB dependencies in human leukemia cell lines and mouse models of leukemia. Together, these data suggest that MYB is an attractive therapeutic target for AML and other hematological malignancies. Therapeutic agents that directly target MYB have yet to be developed, presumably due to the challenges of targeting this intrinsically disordered transcription factor, which lacks tractable ligand binding pockets. Here, we describe the mechanism of action and biological activity of REM-422, a potent, selective, oral small molecule messenger RNA (mRNA) degrader of MYB. REM-422 was identified through screening and medicinal chemistry efforts directed towards identifying small molecules that induce the inclusion of a normally unused ‘poison exon’ (PE), which contains a premature termination codon, into the MYB pre-mRNA transcript. Poison exon inclusion activates the nonsense-mediated decay pathway and promotes the degradation of MYB mRNA. We demonstrate in a cell-free assay that REM-422 acts by selectively facilitating the binding of the U1 snRNP spliceosome complex, which governs exon usage by recognizing 5‘ splice sites, to oligonucleotides containing the MYB PE 5‘ splice site sequence. REM-422 treatment of human leukemia cell lines promotes poison exon inclusion, leading to degradation of MYB mRNA and subsequent reduction in MYB protein levels (Figure 1A). In a panel of AML cell lines, REM-422 demonstrated preferential anti-proliferative activity in cell lines with high MYB expression, and in those shown to be MYB-dependent through functional genomics studies. To understand the pharmacokinetic (PK) and pharmacodynamic (PD) effects of MYB in vivo, Kasumi-1 AML cells were implanted subcutaneously in CB17 scid immunocompromised mice and REM-422 was dosed by oral gavage after the formation of established tumors. QD PO administration of REM-422 demonstrated dose-dependent effects in tumors on MYB mRNA levels, with induction of the MYB poison exon leading to reductions of MYB functional mRNA. In a 21-day study, REM-422 demonstrated significant anti-tumor activity, including tumor regressions at well tolerated dose levels (Figure 1 left). To further investigate the activity of REM-422, AML patient cells were injected into NOG immunocompromised mice and allowed to engraft. After successful engraftment, mice were dosed by oral gavage once daily with REM-422 at 10 mg/kg or vehicle for 24 days. Flow cytometry analysis of bone marrow and peripheral blood samples demonstrated that REM-422 led to the eradication of human leukemia cells from both compartments (Figure 1 right). Together, these data demonstrate that REM-422 treatment leads to degradation of MYB mRNA in preclinical models of AML and supports the therapeutic potential for REM-422 in AML patients.

Vanadium in strongly correlated electron system Ni1-xVxWO4: Paradoxically boosted deNOx reaction under SOx environment via modulating electron correlation

The persistent challenge of NOx selective catalytic reduction degradation in the presence of SOx has remained unresolved for decades. In this study, we report a paradoxical boosted denitration performance more than 20% under the SOx environment through controlling the charge state of V utilizing strongly correlated electron systems (SCES) in Ni1−xVxWO4. Substitutional doped V at the Ni site, and the computed charge gap from DFT confirms the SCES. Through the manipulation of the strong correlation between V and Ni, V preserves the between + 2–3 charge state in the presence of SOx. Furthermore, we achieved a stable oxidation/reduction cycle and higher denitration efficiency by altering the oxidation point of (NH4)HSO4-contaminated Ni1−xVxWO4. This results from deliberate decrease in Coulombic repulsion between Ni and V, improving electron transfer for catalytic performance. This revelation offers a resolution of exceptional denitration performance within SOx in industrial exhaust systems, exploiting the foundational principles of SCES.

Polyol synthesis of one-dimensional Ag nanowires for the photocatalytic degradation of textile dye and effective removal of microbes.

Due to the excess release of hazardous pollutants to the environment, the quest for the synthesis of effective nanomaterials for wastewater treatment is never-ending. Present study reports the polyol synthesis of Ag NWs of ~ 85nm diameter and average length of 4.08µm using PVP and ethylene glycol. The experimental data on the methylene blue dye degradation substantiated the photocatalytic efficiency of Ag NWs (88% degradation in 120min). Furthermore, the Ag NWs exhibited microbial load reducing property in air conditioner condensate water (ACW) within a time period of 60min. Also, the anti-bacterial effect of Ag NWs was estimated using two human pathogenic bacterial strains, namely Staphylococcus aureus and Bacillus cereus. The antibacterial potential of Ag NWs against Staphylococcus aureus and Bacillus cereus was revealed significant with an inhibition zone size of 14 ± 0.1mm and 9 ± 0.1mm, respectively. Hence, the present work validates the potential efficiency of Ag NWs in the degradation of textile dyes and reduction of microbial population.

Z-scheme heterojunction Bi2WO6/NH2-MIL-53(Fe) photocatalyst: Simultaneous efficient photo-Fenton degradation of SMX and photocatalytic reduction of Cr(VI)

The aim of this study was to develop a Z-scheme heterojunction Bi2WO6/NH2-MIL-53(Fe) photo-Fenton catalyst with enhanced electron-hole separation using an in situ growth method. Bi2WO6/NH2-MIL-53(Fe) promotes Fe(II)/Fe(III) cycling under visible light and trace H2O2 (5 μL) conditions, photo-Fenton degraded 82% of SMX within 60 min, 6.3 times that of pure Bi2WO6. It was also able to reduce Cr(VI) (20 mg/L) up to 97% efficiency under strong acidic conditions, which was 2.4 times that of Bi2WO6. In addition, Bi2WO6/NH2-MIL-53(Fe) has good stability and reusability, capable of degrading 75% of SMX and reducing 87% of Cr(VI) even after four cycles of testing. The mechanism of action of this catalyst was investigated by free radical trapping experiments, and the formation of Z-scheme heterojunction was demonstrated. In conclusion, Bi2WO6/NH2-MIL-53(Fe) is a promising photo-Fenton catalyst, which not only efficiently degrades antibiotics, but also exhibits excellent photocatalytic performance against Cr(VI) under strong acid conditions, providing a new idea for the treatment of complex pollutants.

Investigate the effect of ZnO/Bi2O3 nanocomposite: A synergistic versatile approach for biomedical and environmental applications

The escalating increase in the presence of organic and pharmaceuticals residues in the water bodies poses a serious environmental challenge, demanding the efficient photocatalyst for the remediation of microbial and hazardous contaminates. In this context the study addresses the synthesis of ZnO/Bi2O3 composites as an efficient degradation and microbial agents. The hydrothermal prepared nano-structures with (1 %, 3 %, 5 %, 7 %) Bismuth oxide (Bi2O3) concentration delves into an array of characterizations. The X-ray Diffraction (XRD) and Scanning Electron Microscopes (SEM) demonstrate structural and morphological analysis of nano composites. Brunauer Emmett Teller analysis (BET) showcased the surface area while Zeta potential analyzes the electrical conductivity of sample. Additionally, Ultraviolet Visible Spectroscopy (UV) and Photoluminescence Spectroscopy (PL) describe the optical properties of fabricated composites. The results reveal the synergistic effect that leads the effective dual applications of ZnO/Bi2O3 against the environmental concern. Our study finds out the efficient degradation of organic substances (MB dye and pharmaceutical Tetracycline) and strong reduction of pathogenic bacteria under exposes of 5 % ZnO/Bi2O3 composites (optimal sample).

An engineered Escherichia coli Nissle strain prevents lethal liver injury in a mouse model of tyrosinemia type 1

Hereditary tyrosinemia type 1 (HT1) results from the loss of fumarylacetoacetate hydrolase (FAH) activity and can lead to lethal liver injury. Therapeutic options for HT1 remain limited. In this study, we aimed to construct an engineered bacterium capable of reprogramming host metabolism and thereby provide a potential alternative approach for the treatment of HT1. Escherichia coli Nissle 1917 (EcN) was engineered to express genes involved in tyrosine metabolism in the anoxic conditions that are characteristic of the intestine (EcN-HT). Bodyweight, survival rate, plasma (tyrosine/liver function), H&E staining and RNA sequencing were used to assess its ability to degrade tyrosine and protect against lethal liver injury in Fah-knockout (KO) mice, a well-accepted model of HT1. EcN-HT consumed tyrosine and produced L-DOPA (levodopa) in an invitro system. Importantly, in Fah-KO mice, the oral administration of EcN-HT enhanced tyrosine degradation, reduced the accumulation of toxic metabolites, and protected against lethal liver injury. RNA sequencing analysis revealed that EcN-HT rescued the global gene expression pattern in the livers of Fah-KO mice, particularly of genes involved in metabolic signaling and liver homeostasis. Moreover, EcN-HT treatment was found to be safe and well-tolerated in the mouse intestine. This is the first report of an engineered live bacterium that can degrade tyrosine and alleviate lethal liver injury in mice with HT1. EcN-HT represents a novel engineered probiotic with the potential to treat this condition. Patients with hereditary tyrosinemia type 1 (HT1) are characterized by an inability to metabolize tyrosine normally and suffer from liver failure, renal dysfunction, neurological impairments, and cancer. Given the overlap and complementarity between the host and microbial metabolic pathways, the gut microbiome provides a potential chance to regulate host metabolism through degradation of tyrosine and reduction of byproducts that might be toxic. Herein, we demonstrated that an engineered live bacterium, EcN-HT, could enhance tyrosine breakdown, reduce the accumulation of toxic tyrosine byproducts, and protect against lethal liver injury in Fah-knockout mice. These findings suggested that engineered live biotherapeutics that can degrade tyrosine in the gut may represent a viable and safe strategy for the prevention of lethal liver injury in HT1 as well as the mitigation of its associated pathologies.

Comparative catalytic reduction and degradation with biodegradable sodium alginate based nanocomposite: Zinc oxide/N-doped carbon nitride/sodium alginate

Sodium alginate (SA) is a biodegradable macromolecule which is used to synthesize nanocomposites and their further use as catalysis. Zinc oxide (ZnO) and nitrogen doped carbon nitride (ND-C3N4) nanoparticles are prepared using solvothermal and hydrothermal methods, respectively. ZnO/ND-C3N4/SA nanocomposites are successfully synthesized by employing in-situ polymerization. The presence of essential functional groups is confirmed by Fourier transform infrared (FTIR) spectroscopic analysis. Controlled spherical morphology for ZnO nanoparticles, with an average diameter of ∼52 nm, is shown by Scanning electron microscopic (SEM) analysis, while rice-like grain structure with an average grain size ∼62 nm is exhibited by ND-C3N4 nanoparticles. The presence of required elements is confirmed by Energy dispersive X-ray spectroscopic (EDX) analysis. The crystalline nature of nanocomposites is verified by X-ray diffraction spectroscopic (XRD) analysis. The investigation of the catalytic efficiency for degradation and reduction of various organic dyes is carried out on nanoparticles and nanocomposites. Thorough examination and comparison of parameters, such as apparent rate constant (kapp), reduction time, percentage reduction, reduced concentration and half-life, are conducted for all substrates. The nanocomposites show greater efficiency than nanoparticles in both reactions: catalytic reduction and catalytic degradation.

Solution combustion synthesis of metal tungstates for chromium reduction and dye degradation for environmental remediation

Metal tungstates CuWO4 and ZnWO4 nanoparticles were synthesized by simple, efficient, low temperature solution combustion synthesis using metal nitrate and ammonium tungstate. The prepared samples were characterized by different physicochemical characterization techniques i. e.XRD, FTIR, SEM, EDAX, UV–vis DRS, PL and XPS techniques. The petal and flower like morphology of these samples were obtained by using SEM analysis. Based on this novelty, we have studied the photodegradation of methylene blue and rhodamine B dyes in visible light. Results of photocatalytic dye degradation reaction reveal that both the tungstate’s can be employed as photocatalyst under visible light irradiation. ZnWO4 nanoparticles show comparatively higher activity than that of CuWO4, it may due to structural property as well as completely filled d10 orbital of Zn. Both CuWO4 as well as ZnWO4 were also applied to reduce toxic Cr(VI) into harmless Cr(III). This work implemented for the betterment of environmental remediation to the society.

Simultaneous removal of Cr(Ⅵ) and tetracycline from wastewater by dielectric barrier discharge plasma coupled with TiO2/rGO/Cu2O composites: Performance and mechanism

In this study, dielectric barrier discharge (DBD) plasma combined with titanium dioxide/reduced graphene oxide/copper oxide (TiO2/rGO/Cu2O) composites for simultaneous removal of hexavalent chromium (Cr(Ⅵ)) and tetracycline (TC) from wastewater were explored systematically. The TiO2/rGO/Cu2O composites were successfully prepared to improve the specific surface area and charge carrier separation rate. When Cr(Ⅵ) and TC coexist, the two pollutants have better removal efficiency without changing the initial pH. Moreover, the removal efficiency of Cr(Ⅵ) and TC could be further improved in the DBD-TiO2/rGO/Cu2O system, indicating that the TiO2/rGO/Cu2O composites also exhibited good synergistic effects with the DBD plasma. The mechanism exploration showed that the TiO2/rGO/Cu2O composite catalyst could be activated in DBD system to produce various active species by photocatalytic reaction, among which photo-generated electrons and •O2− could significantly enhance Cr(Ⅵ) reduction, while photo-generated holes and •OH could improve TC degradation. More importantly, the intermediate products obtained from TC degradation can be oxidized to •CO2− by photo-generated holes, which can also facilitate the reduction of Cr(Ⅵ). This study shows that DBD combined with TiO2/rGO/Cu2O composites are capable of simultaneous Cr(Ⅵ) reduction and TC degradation, which would provide novel ideas for practical wastewater remediation.