Nitrogen-vacancy-rich molybdenum nitride nanosheets as highly efficient electrocatalysts for nitrogen reduction reaction.

The development of low-cost earth-abundant electrocatalysts to produce ammonia (NH3) with high efficiency for the nitrogen (N2) reduction reaction (NRR) remains challenging. Herein, we propose the development of highly efficient ultrathin nitrogen-vacancy-rich molybdenum nitride nanosheets (MoN-NV) for NRR using basic electrolytes under ambient conditions. In 0.1 M KOH, this catalyst attained a high faradaic efficiency (FE) of ∼14% with an NH3 yield of 22.5 µg h-1 mg-1cat at -0.3 V vs. a reversible hydrogen electrode under ambient conditions. The characterization results and electrochemical studies disclosed that nitrogen vacancies in the MoN-NV nanosheets played a critical role in the enhanced electrocatalytic activity for NRR. Furthermore, the recycling tests confirmed the stability of the catalyst during NRR electrolysis.

Fabrication of biogenic silver nanoparticles from Ficus religiosa bark extract and their application for chromium removal.

Ficus religiosa bark extract was chosen as a reducing agent to fabricate biogenic silver nanoparticles (AgNPs), which were used to treat chromium in synthetic wastewater. The AgNPs formed were characterized using ultraviolet-visible absorption spectroscopy (UV-vis), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results of AgNPs characterization showed that the UV-vis spectrophotometer gave an absorbance peak for AgNPs synthesized from bark extract at 448 nm. The peaks in the XRD pattern of AgNPs synthesized from the bark extract of Ficus religiosa are associated with that of the face-centered-cubic form of metallic silver. The SEM analysis showed clear spherical morphology of AgNPs. These synthesized AgNPs were applied for the removal of chromium from synthetic wastewater. It was seen from the treatment results that above 74.8% removal efficiency was achieved. HIGHLIGHTS: Green synthesis of nanoparticles using plant extracts and their successful application in various fields has been previously studied by various researchers. Ficus religiosa bark extract was used for the synthesis of silver nanoparticles, which after characterization using ultraviolet-visible absorption spectroscopy, scanning electron microscopy, and X-ray diffraction were used to treat chromium in synthetic wastewater prepared in lab. The use of silver nanoparticles for the treatment of heavy metals in wastewater can be considered a good replacement option for the conventional treatment techniques.

Biologically Synthesized Copper Nanoparticles Show Considerable Degradation of Reactive Red 81 Dye: An Eco-Friendly Sustainable Approach.

Diospyros kaki leaf extract was used in this study as a favorable basis for the synthesis of copper nanoparticles (Cu NPs). X-ray diffraction (XRD) and UV-visible spectroscopy approaches were used to characterize the biologically synthesized copper nanoparticles. The XRD analysis showed that copper nanoparticles were face-centered cubic structure. Various experimental levels like conc. of dye, concentration of Cu NPs, pH, reaction time, and temperature were optimized to decolorize reactive red 81 dye using the synthesized Cu NPs. Reactive red 81 dye was decolorized maximum using Cu NPs of 0.005 mg/L. Additionally, reactive red 81 dye was decolorized at its maximum at pH = 6, temperature = 50°C. Our study reported that chemical oxidation demand (COD) and total organic carbon (TOC) deduction efficacies were 74.56% and 73.24%. Further degradation study of reactive red 81 dye was also carried out. Cu NPs have the ability and promising potential to decolorize and degrade reactive red 81 dye found in wastewater.

Synthesis of nickel nanoparticles using Citrullus colocynthis stem extract for remediation of Reactive Yellow 160 dye.

In current years, pollution caused by synthetic dyes has become one of the most serious environmental issues. By rapidly developing industrial units, effluents having synthetic dyes are directly or indirectly being discharged into the environment. Bio-sorption is cost-effective way for the eradication of toxic dyes present in textile effluent. The present study involves the synthesis of nickel nanoparticles using Citrullus colocynthis stem extract. The characterization of synthesized nickel nanoparticles (Ni-NPs) was done by SEM. The synthesized Ni-NPs were used to degrade the Reactive Yellow 160 dye following the optimization of different experimental parameters. The maximum decolorization (91.4%) was obtained at 0.02% dye conc., 9 mg/L conc. of Ni-NPs, pH 7 at 40 °C. TOC and COD were used to assess the efficiency of this experiment. Percent reduction in COD and TOC was found to be 84.35% and 83.24% respectively. The degradation pathway of dye under study confirmed the formation of non-toxic end-products.

Bioremediation of Synthetic and Industrial Effluents by Aspergillus niger Isolated from Contaminated Soil Following a Sequential Strategy.

The present study aimed to assess and compare the ability to remediate synthetic textile and industrial wastewaters by Fenton treatment, a biological system and sequential treatments using Aspergillus niger (A. niger). All studied treatments were found to be effective in decolorization of the effluents under study. Fenton treatment followed by A. niger showed excellent potential for the maximum decolorization of the synthetic and industrial effluents under study. The effectiveness of sequential treatment was evaluated by water quality parameters such as total organic carbon (TOC), Biological Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) before and after each treatment. The results indicated that A. niger is an effective candidate for detoxification of textile wastewaters.

Gemmomodification: an emerging source of natural antioxidants from Silybum marianum.

Gemmomodification is a form of herbal medicine in which young freshly growing buds of plants are used. At germinating stage, plants metabolic activities are maximum and various nutrients, hormones enzymes and bioactive phytoconstituents are released and available at this stage. Plants may be promising source of natural antioxidants at growing stage. Oxidative stress leads to many chronic and degenerative diseases. Antioxidants are very essential for human body; they can protect the body from damage caused by free radical induced oxidative stress. This research project had been designed to investigate the antioxidant potential of gemmo modified and native (dry leaves) extract of Silybum marianum. Total phenolic contents was calculated by using Folin-Ciocalteu reagent and antioxidant potential was evaluated by using four radical assays (DPPH, ABTS, Super oxide and nitric oxide), reducing power assay and lipid peroxidation assay spectrophotometrically. Gemmo modified extract showed significantly higher (p<0.050) TPC (830 mg GAE/g of plant extract) as compared to native extract (800 mg GAE/g.) Results of this study revealed that gemmo modified extract demonstrated better antioxidant potential than natively used parts of Silybum marianum.

Short communication: synthesis and applications of Coumarin.

In this work, coumarin was synthesized by Perkin reaction using salicylaldehyde, acetic acid and sodium acetate. Due to the misuse of acetic anhydride in narcotics synthesis, acetic acid was substituted for acetic anhydride in Perkin reaction. On the basis of this substitution a hypothesis was proposed that "acetic acid could be substituted as an acetylating agent in place of acetic anhydride in coumarin synthesis via Perkin reaction". In the present research project, salicylaldehyde was prepared from phenol, sodium hydroxide and chloroform for further procedure. Then four different coumarin samples were synthesized by changing the parameter of reactants proportions. From this parameter, we designed a trend of high product yield. Yields of Coumarin samples will lead towards either acceptance or rejection of the above proposed hypothesis. In the next step, these Coumarin samples were characterized by age yield (%), solubility and melting points. At last Antibacterial activities of all the four coumarin samples were evaluated against two bacterial strains; E.coli and S.aureus. As a consequence of all above, it was inferred that the yields of all coumarin samples obtained were low as compared to the yield obtained by the use of acetic anhydride in previous reports. This led to the rejection of proposed hypothesis. Among four Coumarin samples, sample-4 obtained by taking equal amounts of all the reactants had shown maximum yield, best characterization and excellent antibacterial activity. In spite of low yields obtained, the remarkable antibacterial activities of Coumarin samples have enabled us to suggest coumarin as a strong antibacterial agent and it must be employed for further applications.