Experimental and DFT Studies of Au Deposition Over WO_(3)/g-C_(3)N_(4) Z-Scheme Heterojunction

A typical Z-scheme system is composed of two photocatalysts which generate two sets of charge carriers and split water into H2 and O2 at different locations.Scientists are struggling to enhance the efficiencies of these systems by maximizing their light absorption,engineering more stable redox couples,and discovering new O2 and H2 evolutions co-catalysts.In this work,Au decorated WO3/g-C3N4 Z-scheme nanocomposites are fabricated via wet-chemical and photo-deposition methods.The nanocomposites are utilized in photocatalysis for H2 production and 2,4-dichlorophenol(2,4-DCP)degradation.It is investigated that the optimized 4Au/6%WO3/CN nanocomposite is highly efficient for production of 69.9 and 307.3μmol h−1 g−1 H2 gas,respectively,under visible-light(λ>420 nm)and UV–visible illumination.Further,the fabricated 4Au/6%WO3/CN nanocomposite is significant(i.e.,100%degradation in 2 h)for 2,4-DCP degradation under visible light and highly stable in photocatalysis.A significant 4.17%quantum efficiency is recorded for H2 production at wavelength 420 nm.This enhanced performance is attributed to the improved charge separation and the surface plasmon resonance effect of Au nanoparticles.Solid-state density functional theory simulations are performed to countercheck and validate our experimental data.Positive surface formation energy,high charge transfer,and strong non-bonding interaction via electrostatic forces confirm the stability of 4Au/6%WO3/CN interface.

Organic and Inorganic Mercury in Biological Samples of Flouresecent Lamp Industries Workers and Health Risks

Objective The present study aims to investigate the concentrations of Hg and its aspects methyl mercury(Me-Hg)and inorganic mercury(I-Hg)in the biological samples(BSs)of fluorescent lamp industries workers(FLIWs).Methodology Different BSs including red blood cells(RBCs),plasma,urine,hair and nails were collected from the workers exposed to Hg and unexposed persons were selected as control group to measure both the T-Hg concentration as well as its species in different biological samples through quantitative analysis.Health data was collected through questionnaire survey.Results The mean concentrations of T-Hg(31.9μg/L),Me-Hg(27.7μg/L),and I-Hg(5.36μg/L)in RBCs were found significantly(P<0.001)higher among the workers(n=40)as compared to the control group(n=40).Similarly the mean Hg concentrations in plasma,urine,hair and nails were also significantly higher among the workers than the control group.The statistical relation between Hg concentration and demographic characteristics observed that workers experience and fish consumption has increased the Hg concentration while age,weight and smoking found no significant effect on Hg concentration in the BSs.Conclusion The study observed that the workers were highly exposed to high concentration of Hg and they are at a high health risk.

Surface Tension, Density and Viscosity Studies on the Associative Behaviour of Oxyethylene-Oxybutylene Diblock Copolymers in Water at Different Temperatures

The associative properties of methoxy (CH3O-) ended E58B11 and hydroxyl (-OH) ended E56B19 oxyethylene-oxybuty- lene diblock copolymers in aqueous solution at different temperature are reported in this paper. For both copolymers, E represents an oxyethylene (-[CH2CH2O]-) unit and B an oxybutylene (-[CH(C2H5)CH2O]-) unit while the subscripts denote the number average block length. Surface tension measurements were used to find out surface excess concentrations (Γm), area per molecule (αs1 ) at air/water interface and Gibbs free energy for adsorption (△G0ads ) for the pre-micellar region at four temperatures. Likewise thermodynamic parameters of micellization such as, critical micelle concentrations (CMC), enthalpy of micellization (△H0mic ), standard free energy of micellization (△G0mic) and entropy of micellization (△S0mic ), were also obtained using surface tension measurements. Solution densities were used to deter-mine the partial specific volume of micelle ( Vmic) and micellar density (ρmic). Dilute solution viscosities have been used to estimate the intrinsic viscosities [η], solute-solvent interaction parameter (KH) and hydration value of micelle (Wh) at various temperatures. The effect of temperature on the micelle properties is also discussed.

Call Census,Habitat Suitability Modeling,and Local Communities’Perceptions for the Conservation of a Globally Threatened Avian Flagship Species

The Western tragopan(Tragopan melanocephalus)is recorded in the IUCN Red List of 2017 as a vulnerable bird species in Pakistan.This study provides valuable information for the conservation of Western tragopan,which is a globally threatened avian flagship species in Pakistan.This study was conducted to investigate and resolve the conservation challenges surrounding the species in two major habitat zones-Salkhala Game Reserve and Machiara National Park.The study was implemented in May-June 2020 for population density using call count data.Also,questionnaire was used for local residents’perceptions and habitat suitability modeling map was generated using the MaxEnt model based on previously recorded occurrence points as well as recorded in the survey.A total of 26 western Tragopans were identified by call count during the sampling period.Moreover,about 77.3%cited Western Tragopan they more likely to hunt while the remaining 22.6%locals recorded other pheasant.About 45.3%of this hunting for fun but only 22%for economic values and only 3%of people consider hunting as a part of their culture.Results of modeling habitat suitability of the Western tragopan showed that the species suitable habitats are small and patchy in Pakistan.We found that the Normalized Difference Vegetation Index(NDVI)with 40.6 percent contribution was the most important variable in shaping the species distribution.Our model identified some new suitable patches which can be the target of future field monitoring for finding new populations of the species and future conservation planning.

Designing single atom catalysts for exceptional electrochemical CO_(2) reduction

The release of anthropogenic CO_(2)emissions into the atmosphere has significantly accelerated global warming within the past few decades.According to the latest data,it is predicted that the concentration of CO_(2)will rise to 800 ppm over this century,and could reach 2000 ppm by 2300.Such high level of CO_(2)is expected to result in significant increase in global temperature as well as ocean acidification[1].

MICELLAR PARAMETERS OF DIBLOCK COPOLYMERS AND THEIR INTERACTIONS WITH IONIC SURFACTANTS

The interactions of non-ionic amphiphilic diblock copolymer poly（oxyethylene/oxybutylene） （E39B18） with anionic surfactant sodium dodecyl sulphate （SDS） and cationic surfactant hexadecyltrimethylammonium bromide （CTAB） were studied by using various techniques such as surface tension, conductivity, steady-state fluorescence and dynamic light scattering. Surface tension measurements were used to determine the critical micelle concentration （CMC） and thereby the free energy of micellization （AGmic）, free energy of adsorption （AG^ds）, surface excess concentration （F） and minimum area per molecule （A）. Conductivity measurements were used to determine the critical micelle concentration （CMC）, critical aggregation concentration （CAC）, polymer saturation point （PSP）, degree of ionization （tr） and counter ion binding （l]）. Dynamic light scattering experiments were performed to check the changes in physiochemical properties of the block copolymer micelles taken place due to the interactions of diblock copolymers with ionic surfactants. The ratio of the first and third vibronic peaks （11/Is） indicated the polarity of the pyrene micro environment and was used for the detection of micelle as well as polymer-surfactant interactions. Aggregation number （N）, number of binding sites （n） and free energy of binding （AGb） for pure surfactants as well as for polymer-surfactant mixed micellar systems were determined by the fluorescence quenching method.