Construction of Ag/CdZnS QDs nanocomposite for enhanced visible light photoinactivation of Staphylococcus aureus.

With increasing use of antibiotics, the development of antibiotic-resistant pathogens poses a serious threat to human health and the environment. Photocatalytic inactivation of these harmful pathogens is one of the novel and non-antibiotic treatments. The study fabricated Ag NPs decorated CdZnS QDs via a facile and biological co-precipitation method using L. camara plant extract as a green alternative to treat the toxic chemicals. The fabricated Ag/CdZnS QDs (NCs) were prepared for the efficient treatment of antibiotic-resistant pathogens as they raise a major global concern. The fabricated NCs were characterized with various characterization techniques to verify its physicochemical properties. The fabricated NCs have shown excellent photo-sterilization performance of 97 % against S. aureus. The excellent activity was attributed to the decoration of Ag NPs on CdZnS QDs as it helped in shortening band gap, improved visible light absorption ability, increased active sites, and boosted photogenerated electron/hole pairs stability. Radical trapping experiment and ESR analysis indicated the involvement of •OH and h+ in the photoinactivation of bacteria. The photo sterilization reaction of NCs was carried out under different environmental conditions, including light and dark conditions and different pH conditions. The experiment was carried out in sewage-treated water in order to test the real-time application, and the fabricated NCs achieved excellent 95.9 % photo-inactivation of S. aureus cells in sewage treated water and the Chemical Oxygen Demand (COD) of the system was increased after photo inactivation treatment. The fabricated NCs have also shown excellent reusable efficiency of 95% after six runs and the photostability and anti-corrosive nature of NCs were confirmed. The study provides an insight for the employment of photocatalysis for the sterilization of pathogens in real time aquatic environment across the globe.

Interstitial decoration of Ag linking 3D Cu2O octahedron and 2D CaWO4 for augmented visible light active photocatalytic degradation of rifampicin and genotoxicity studies.

A morphological oriented highly active Cu2O-Ag-CaWO4 (CAC) nano-heterojunction was fabricated for the visible light driven degradation of rifampicin (RFP). Octahedron shaped Cu2O being a base material, where the Tagetes shaped CaWO4 and Ag were embedded on it. The shape-controlled morphology of Cu2O and CaWO4 as well as Ag decoration influence high degree of adsorption of RFP and interfacial charge transfer between the nano-heterojunction. Further, the larger specific surface area (129.531 m2/g) and narrow band gap energy (2.57 eV) of CAC nano-heterojunction than the controls support the statement. Positively, CAC nano-heterojunction following Z-scheme-type charge transport mechanism attained 96% of RFP degradation within 100 min. O2•- and •OH are the primarily involved reactive oxidation species (ROS) during the photocatalytic reactions, determined by scavenger study and ESR analysis. The stability and reusability of the CAC nano-heterojunction was assessed through performing cyclic experiment of RFP degradation and it holds 96.8% of degradation even after 6th cycle. The stability of CAC nano-heterojunction after photodegradation was further confirmed based on crystalline pattern (XRD analysis) and compositional states (XPS analysis). Intermediates formed during RFP degradation and its toxicity was discovered by using GC-MS/MS and ECOSAR analysis respectively. The end-product toxicity against bacterial system and genotoxicity of CAC nano-heterojunction against Allium cepa were evaluated and the results were seemed to have no negative causes for the aquatic lives.

Construction of p-n-p nano heterojunction through coupling La2O3, (BiO)2CO3 and Ag3PO4 for effective photocatalytic degradation of doxycycline: Insights into mechanism, pathway and intermediate toxicity evaluation.

The present work is centred around the development of La2O3/(BiO)2CO3/Ag3PO4 (LBA), a p-n-p nano-heterojunction to photodegrade doxycycline under visible light irradiation. Here, ultrasonication assisted co-precipitation method was employed to synthesize the photocatalyst. The photocatalyst was characterized using different analysis such as SEM, TEM, elemental mapping, XRD, XPS, FTIR, Raman, BET, DRS, PL and EIS which confirmed the successful fabrication of LBA and their excellent ability to refrain the e-/h+ recombination owing to the construction of the heterojunction. LBA was found to degrade DOX by 91.75 % with the high mineralization of 87.23%. The impact of the reaction parameters influencing the photodegradation process including the concentration of the NCs and DOX, pH and the influence of the commonly present anions were studied. The stability and reusability of the LBA was assessed through subjecting it to four cycles of photodegradation of DOX. In addition, the recovered LBA was characterized through XPS and XRD analysis to confirm the particles stability and reusability. The active participation of the photogenerated charges and the reactive oxygen species were identified through the scavenging assay and ESR analysis. Further, GC-MS/MS analysis was performed to put forward a plausible photodegradation pathway. The toxicity of the end products as well as the intermediates was predicted through ECOSAR software.

Unravelling the enhanced rifampicin photocatalytic degradation over green-synthesized SrO2@SnIn4S8 p-n heterojunction: Pathway, toxicity evaluation and mechanistic insights.

In recent years, the discharge of pharmaceutical drugs into aquatic ecosystems has become a growing concern, posing a significant threat to aquatic life. In response to this environmental challenge, advanced oxidation processes have gained prominence in wastewater treatment due to their efficacy in eliminating pharmaceutical pollutants and their potential for reusability. In this study, we have fabricated SnIn4S8 coupled SrO2 nano-heterojunction (NH) using a greener co-precipitation approach using leaf extract derived from Acaphyla wilkesiana. The resulting NH exhibited exceptional photocatalytic activity against rifampicin (RIF), achieving a remarkable 97.4% degradation under visible light, surpassing the performance of its individual components. The morphological characteristics of the NH were thoroughly analyzed through SEM, TEM, XRD, and XPS techniques, while EIS, DRS, and BET techniques provided valuable insights into its photocatalytic and optical properties. Furthermore, radical scavenging assays and ESR analysis identified hydroxyl radicals (•OH) and superoxide radicals (O2•-) were the species contributing to the visible light-driven photocatalytic degradation. The study also elucidated the potential degradation pathways and intermediates of RIF through GC-MS analysis. Additionally, the toxicity of the produced intermediates was assessed using the ECOSAR model. The findings have significant implications for the treatment of pharmaceutical pollutants and underscore the importance of eco-friendly synthesis methods in addressing environmental challenges.

Self-propelled nanojets an interfacial Schottky junctions modulated oxygen vacancies enriched for enhanced photo-Fenton degradation of organic contaminant: Improving H2O2 generation, Fe3+/Fe2+ cycle and enhancing plant metabolism.

The study reports an innovative approach on sunlit driven heterostructure photocatalytic generation of H2O2 and removal of cefixime. In the present work, we have fabricated Mn/Mg doped CoFe2O4 modified CaCr2O4 decorated by Ag3PO4 quantum dots (Ag3PO4 QDs), a p-n-p nano heterojunction. The study promotes the photocatalytic production of H2O2 and self-Fenton photocatalytic degradation of cefixime. Egg white-assisted synthesis of Mn-doped CoFe2O4 causes the lattice oxygen defect, which enhances the photocatalytic activity. Lattice oxygen defect enable the adsorption of O2, which enable the conversion of •O2 in the valence band of CoFe2O4 for the endogenous production of H2O2. The higher in the surface area enhance the photocatalytic activity under visible light irradiation. Mn-CoFe2O4-CaCr2O4-Ag3PO4 QDs enables the complete photocatalytic degradation of cefixime (99.9%) and the complete removal was determined by total organic carbon (TOC) removal and it was around 99.4%. Meanwhile the photocatalytic degradation pathway of cefixime was determined by LC-MS/MS. Reusability of the nano heterojunction was determined by six cycle test, and the reusability of the nano heterojunction was 99.8%. Further, the toxicity of the nanomaterial was studied in maize plant and the results shows that the nanoheterojunction enhances the maize growth. The study systematically reveals the robust activity of nano heterojunction for sustainable water treatment.

Sunlight promoted self-fenton photodegradation and pathway of doxycycline: Interactive effects of nanomaterial on bean plant and its genotoxicity against Allium cepa.

Photocatalytic induction of electron/hole recombination, surface property and light response ability effectively enhance the photocatalytic activity of nanomaterial. In this work, the effective charge carrier separating Sn/Mn-ZnFe2O4-CdFe2O4-Ag3PO4 Quantum dots (M/SZFO-CFO-AP QDs) was fabricated for photocatalytic degradation of doxycycline (doxy) antibiotic. The result showed enhanced photocatalytic activity of doxy and the degradation efficiency of doxy was about 98.8% in short span of time. The calculated WH plot and urbach energy of prepared photocatalyst exhibited evidence for the prevalence of point defects and its contribution to efficient charge separation and transferability. The total organic carbon (TOC) removal was found to be 98.9%, which depicts the complete mineralization of doxy. The synergetic charge transfer of n-p-n heterojunction enables the effective removal of doxy under visible light irradiation. Further, the genotoxicity study was determined by interacting the SZFO-CFO-AP QDs with Allium Cepa. The results depict that SZFO-CFO-AP QDs show lower toxicity level and there were no trace of defective mitotic phases and micro nuclei. Further, the progression and development of bean plant was determined after treating with prepared nanomaterials and the result showed the enhanced growth in SZFO-CFO-AP QDs treated bean plant compared to the counterparts. Therefore, the prepared SZFO-CFO-AP QDs was can be used as an environmental friendly photocatalyst for effective treatment of antibiotic present in the water bodies.

Novel insight on chemo-specific detection of toxic environmental chromium residues existing as recalcitrant Cr(III)-carboxyl complexes using plasmonic silver nanoplatform bi-functionalized with citrate and PVP.

Chromium (Cr) is a toxic environmental pollutant that majorly exists in trivalent and hexavalent forms. Though Cr(VI) is more dangerous than Cr(III), the trivalent Cr forms complexes with environmentally-available organic molecules. This makes them potentially harmful and difficult to detect. In this study, we have designed an ultrasensitive plasmonic nanosensor using citrate and PVP functionalized Ag nanoparticles (Ag-citrate-PVPNPs) for the detection of trivalent chromium organic complexes such as Cr(III)-EDTA (Cr-E), Cr(III)-acetate (Cr-A), Cr(III)-citrate (Cr-C) and Cr(III)-tartrate (Cr-T). The nanoparticles (NPs) were structurally characterized by XRD, SEM, HRTEM, SAED, EDX and elemental mapping. The citrate and PVP molecules played a vital role in the detection mechanism and stability of the sensor. Upon detection, the yellow-colored Ag-citrate-PVP NPs turned into different shades of brown depending on the type of the Cr complex and concentration. It was accompanied by diminishing and/or shifting UV-Visible absorbance peaks due to the aggregation of Ag-citrate-PVP NPs. Further, a linear relationship was observed between absorbance reduction and analyte concentration. The selectivity tests showed that the sensor was non-functional to other metal ions and inorganic anions. The sensor was optimized using pH and temperature studies. The mechanism of detection was elucidated with the help of characterization techniques such as Raman spectroscopy, FTIR, XPS and UV-visible spectrophotometer. The limit of detection (LOD) was found to be 3.29, 4.87, 1.76 and 1.79 nM for Cr-E, Cr-A, Cr-C and Cr-T complexes respectively. This study provides a rapid and sensitive approach for the detection of multiple Cr(III)-organic complexes present in an aqueous solution.

Zn alleviated salt toxicity in Solanum lycopersicum L. seedlings by reducing Na+ transfer, improving gas exchange, defense system and Zn contents.

Soil secondary salinization is a serious menace that has significant influence on the sustainability of agriculture and threatens food security around the world. Zinc (Zn) as an essential plant nutrient associated with many physio-biochemical processes in plants and improve resistance against various abiotic stresses. The role of Zn in acclimation of Solanum lycopersicum L. challenged with salt stress is miserly understood. A hydroponic study was performed with two tomato varieties (Riogrande and Sungold) exposed to the salinity stress (0 mM and 160 mM NaCl) under two Zn concentrations (15 µM and 30 µM ZnSO4). The results revealed that salt stress exerted strongly negative impacts on root and shoot length, fresh and dry biomass, plant water relations, membrane stability, chlorophyll contents, Na+/K+ ratio along with inferior gas exchange attributes and activities of antioxidant enzymes. Moreover, Riogrande was found to be more resistant to salinity stress than Sungold. However, Zn supply significantly alleviated the hazardous effects of salinity by altering compatible solutes accumulation, photosynthetic activity, water relation, soluble sugar contents and providing antioxidant defense against salt stress. The salinity + Zn2 treatment more obviously enhanced RWC (19.0%), MSI (30.8%), SPAD value (17.8%), and activities of SOD (31.7%), POD (28.5%), APX (64.5%) and CAT (23.3%) in Riogrande than Sungold, compared with the corresponding salinity treatment alone. In addition, salinity + Zn2 treatment significantly (P > 0.05) ameliorated salinity stress due to the depreciation in Na+/K+ ratio by 63.3% and 40.8%, Na+ ion relocation from root to shoot by 10.4% and 6.4%, and thereby significantly reduced Na+ ion accumulation by 47.4% and 16.3% in the leaves of Riogrande and Sungold respectively, compared to the salinity treatment alone. Therefore, it was obvious that 30 µM Zn concentration was more effective to induce resistance against salinity stress than 15 µM Zn concentration. Conclusively, it can be reported that exogenous Zn application helps tomato plant to combat adverse saline conditions by modulating photosynthetic and antioxidant capacity along with reduced Na+ uptake at the root surface of tomato plant.

Green synthesis of two-electron centre based ZnO/NiCo2S4 QDs-OVs using Punica granatum fruit peel extract for an exceptional visible light photocatalytic degradation of doxycycline and ciprofloxacin.

Biosynthesis of nanomaterials using plant extract makes them attractive in the field of photocatalysis as they are environmental friendly. The current study focused on the biosynthesis of ZnO/NiCo2S4 QDs (NCs) using Punica granatum fruit peel extract as the reducing agent. The nanomaterials were characterized with XRD, FTIR, Raman, SEM, TEM, UV-vis DRS, BET, PL, EIS, and ESR analysis and were used for photocatalytic degradation of doxycycline (DOX) and ciprofloxacin (CIP). The bandgap of ZnO is 3.2 eV, and the decoration of NiCo2S4 QDs aids in narrowing the bandgap (2.8 eV), making the NCs visible light active. The fabricated NCs achieved 99 and 89% degradation of DOX and CIP respectively. The photocatalytic efficiency of ZnO/NiCo2S4 QDs was much higher compared to individual ZnO and NiCo2S4 QDs. The half-life period of DOX and CIP were evaluated to be 58 and 152 min respectively. The percentage of TOC removal in the photodegraded product of DOX and CIP was estimated to be 99 and 89% respectively, indicating the mineralization of the compounds. The enhanced photocatalytic efficiency of the NCs was attributed to the narrowed visible light active bandgap, synergistic charge transfer across the interface, and lower charge recombination. The intermediates formed during the photocatalytic degradation of DOX and CIP were analyzed using GC-MS/MS analysis, and the photodegradation pathway was elucidated. Also, the toxicity of the intermediates was computationally analyzed using ECOSAR software. The fabricated ZnO/NiCo2S4 QDs have excellent stability and reusability, confirmed by XRD and XPS analysis. The reusable efficiency of the NCs for the photocatalytic degradation of DOX and CIP were 98.93, and 99.4% respectively. Thus, the biologically fabricated NCs are shown to be an excellent photocatalyst and have wide applications in environmental remediation.

Designing novel MgFe2O4 coupled V2O5 nanorod for synergetic photodegradation of tetracycline with enhanced visible-light energy harvesting: Photoluminescence, kinetics, intrinsic mechanism and bactericidal effect.

The present study focused on the enhancement of degradation of an important pharmaceutical pollutant, tetracycline with the help of nano photocatalyst under visible light irradiation. The study found that the synergetic effect of novel MgFe2O4-V2O5 enhanced the photocatalytic degradation of tetracycline. Here, the photocatalyst was synthesized by sonochemical technique. Scanning electron microscopy image indicates the coupling of MgFe2O4 nanocapsules on the surface of the V2O5 nanorod. The bandgap of MgFe2O4 (1.8 eV) and V2O5 (2.5 eV) was shifted to 2.32 eV in MgFe2O4-V2O5 to promote visible-light harvesting and it was depicted by the UV-visible DRS. XPS was used to identify the presence of chemical states with the existence of Mg 1s, Fe 2p, V 2p, and O 1s. The electrochemical impedance spectroscopy and photoluminescence spectra indicate the better separation of charge carriers owing to the formation of type II heterojunction formation. The tetracycline (25 mg/L) was degraded with MgFe2O4-V2O5 (150 mg/L) that exhibited 3.3 and 5 folds enhanced rates than its counterparts (MgFe2O4 and V2O5) owing to synergism. The possible intermediate formation and degradation pathway was determined based on GC/MS analysis. TOC analysis of end products indicated maximum mineralization of tetracycline. The MgFe2O4-V2O5 showed excellent recycling ability and reusability. The key photo-degradation of tetracycline was occurred by the generation of hydroxyl radicals. The MgFe2O4-V2O5 exhibited high antibacterial activity that ensures the dual functionality of the prepared nanocomposites (NCs). Therefore, the present study displays MgFe2O4 decorated V2O5 nanorod as an ideal candidate for environmental remediation.

Effect of Elevated CO2 on Biomolecules' Accumulation in Caraway (Carum carvi L.) Plants at Different Developmental Stages.

Caraway plants have been known as a rich source of phytochemicals, such as flavonoids, monoterpenoid glucosides and alkaloids. In this regard, the application of elevated CO2 (eCO2) as a bio-enhancer for increasing plant growth and phytochemical content has been the focus of many studies; however, the interaction between eCO2 and plants at different developmental stages has not been extensively explored. Thus, the present study aimed at investigating the changes in growth, photosynthesis and phytochemicals of caraway plants at two developmental stages (sprouts and mature tissues) under control and increased CO2 conditions (ambient CO2 (a CO2, 400 ± 27 µmol CO2 mol-1 air) and eCO2, 620 ± 42 µmol CO2 mol-1 air ppm). Moreover, we evaluated the impact of eCO2-induced changes in plant metabolites on the antioxidant and antibacterial activities of caraway sprouts and mature plants. CO2 enrichment increased photosynthesis and biomass accumulation of both caraway stages. Regarding their phytochemical contents, caraway plants interacted differently with eCO2, depending on their developmental stages. High levels of CO2 enhanced the production of total nutrients, i.e., carbohydrates, proteins, fats and crude fibers, as well as organic and amino acids, in an equal pattern in both caraway sprouts and mature plants. Interestingly, the eCO2-induced effect on minerals, vitamins and phenolics was more pronounced in caraway sprouts than the mature tissues. Furthermore, the antioxidant and antibacterial activities of caraway plants were enhanced under eCO2 treatment, particularly at the mature stage. Overall, eCO2 provoked changes in the phytochemical contents of caraway plants, particularly at the sprouting stage and, hence, improved their nutritive and health-promoting properties.

Antibacterial and Antifungal Activity of the Extracts of Different Parts of Avicennia marina (Forssk.) Vierh.

Increased problems associated with side effects and bacterial resistance of chemical drugs has prompted the research focus on herbal medicines in the past few decades. In the present investigation, the antimicrobial activity of the various parts of Avicennia marina (AM), a mangrove plant, has been evaluated. The plants were collected from the Jazan area of the Kingdom of Saudi Arabia. Primary extracts of roots, stem, leaves, fruits, and seeds were made in ethanol and fractioned in ethanol, ethyl acetate, petroleum ether, chloroform, and water. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the extracts were determined against Bacillussubtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. It has been observed that the chloroform extract of roots of the AM exhibited inhibitory effects against both S. aureus (MIC = 1.5 ± 0.03 mg/mL) and E. coli (MIC = 1.7 ± 0.01 mg/mL). The ethanolic extract of the AM roots has shown antibacterial activity against Pseudomonas aeruginosa (MIC = 10.8 ± 0.78 mg/mL), Bacillussubtilis (MIC = 6.1 ± 0.27 mg/mL), Staphylococcus aureus (MIC = 2.3 ± 0.08 mg/mL), and Escherichia coli (MIC = 6.3 ± 0.28 mg/mL). The leaf extract of the AM in ethyl acetate showed antibacterial activity against S. aureus and E. coli. Antifungal activity of these extracts was also investigated against Aspergillus fumigatus and Candida albicans. Ethanolic extract of roots and seeds of the AM has shown antifungal activity against Aspergillus fumigatus when applied individually. Ethanolic extract of the AM fruits has shown an inhibitory effect on the growth of Aspergillus fumigatus and Candida albicans. It is suggested that the plant extracts of AM have tremendous antimicrobial activity against a group of microbes, and this effect depends on both the plant part and the solvent used for extraction. Therefore, this plant can be considered to treat various diseases caused by antibiotic-resistant bacteria.