Amount Of ZnS Research Articles

Application of ZnS:Ni Loaded on Sponge‐Activated Carbon as an Efficient Adsorbent for Dye Removal

AbstractIn the present work, a ZnS:Ni loaded on sponge‐activated carbon (SAC) was synthesized and applied as an effective adsorbent to remove bromophenol blue (BPB) dye from aqueous solutions. Various techniques such as Fourier‐transform infrared, X‐ray diffraction, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and Brunauer‐Emmett‐Teller (BET) were used to characterize ZnS:Ni–SAC. The effective parameters such as BPB concentration, amount of ZnS:Ni–SAC, ultrasonic time, and pH of the aqueous solution were investigated and optimized by response surface methodology. To investigate the accuracy and reliability of the proposed method, the analysis of variance was used based on p‐values and F‐test. The optimal values of the parameters were obtained using the desirability function, and they were as follows: 15 mg L−1 BPB concentration, 20 min sonication time, 18 mg of ZnS:Ni–SAC, and pH = 7. To evaluate the adsorption mechanism and calculation of maximum adsorption capacity, different adsorption isotherms were studied, and according to the obtained results, the Langmuir isotherm model showed the highest compatibility due to its higher R2 (0.997). Also, the proposed adsorbent represented good adsorption capacity (125 mg g−1). Moreover, kinetic studies proved the applicability of the pseudo‐second‐order model (R2 = 0.986) compared to other models. The achieved results confirmed the applicability of ZnS:Ni–SAC as a versatile adsorbent for the removal of BPB.

Improving the short wavelength response of the multi-crystalline silicon solar cell by using 10% Erbium doped ZnS nanoparticle-based downshifting layer

This study describes how a polymer/ZnS composite layer with antireflection, scattering, and downshifting properties improved the short wavelength response of multi-crystalline silicon (mc-Si) solar cells. The downshifting layer is made up of 10% erbium-doped ZnS nanoparticles that are dispersed in a PMMA matrix at concentrations ranging from 1 mg/ml to 10 mg/ml and applied by spin coating to the front surface of an mc-Si solar cell. The chemical route method is used to create the 10% erbium-doped ZnS NP. XRD, SEM, UV–Vis, and PL techniques are used to identify the synthesized NP. EQE, IQE, reflectance, and J-V measurement serve as distinguishing characteristics for mc-Si solar cells with and without a downshifting layer. The cubic structure of the nanoparticle has been confirmed by the XRD pattern of 10% erbium-doped ZnS NP. The spherical shape of the nanoparticle was visible in the SEM image. The nanoparticle's ability to absorb high-energy photons and release low-energy photons that met the downshifting requirement was confirmed by the UV–Vis and PL spectra. Solar cells with a downshifting layer expose their EQE spectra to enhance their UV response at short wavelengths. Both EQE and J-V measurements are used to calculate the short circuit current density. In the EQE and J-V measurements, it differs from the bare one by 4.76% and 3.57%, respectively. The short circuit current density has confirmed that the 3 mg/ml amount of ZnS:10 %Er NP/PMMA used as a downshifting layer in this study is the right concentration to improve the short wavelength response when applied to the top surface of the mc-Si solar cell.

ZnS/Cd1-xZnxS composite photocatalyst synthesized with excessive strong alkali solution as a hydrothermal solvent: The chemical equilibrium theory of the synthesis process and its influence on photocatalytic performance

The ZnS/Cd1-xZnxS composite photocatalyst was successfully synthesized using a hydrothermal solvent by adding excess hydroxide ions. The ZnS/Cd1-xZnxS composite photocatalyst showed excellent photocatalytic activity for hydrogen production with a hydrogen evolution rate of 21.8 mmol/g−1 h−1, which is the highest photocatalytic activity reported to date among visible-light-driven photocatalysts without loading cocatalysts. According to the theoretical calculation and analysis of the chemical equilibrium in the synthesis process, the synthesized Cd1-xZnxS solid solution contained a certain amount of ZnS. A certain amount of ZnS was also contained in the synthesized Cd1-xZnxS solid solution based on experimental results, thus demonstrating the validity of the theoretical calculation. Experimental results showed that the key factor affecting the photocatalytic activity of hydrogen production for the ZnS/Cd1-xZnxS composite photocatalyst was not the heterojunction formed between ZnS and Cd1-xZnxS but rather the stacking fault structures in the Cd1-xZnxS solid solution. However, more stacking fault structures could be formed in the Cd1-xZnxS solid solution due to the presence of ZnS.

ZnO-ZnS Heterojunctions: A Potential Candidate for Optoelectronics Applications and Mineralization of Endocrine Disruptors in Direct Sunlight.

Simple solution combustion synthesis was adopted to synthesize ZnO–ZnS (ZSx) nanocomposites using zinc nitrate as an oxidant and a mixture of urea and thiourea as a fuel. A large thiourea/urea ratio leads to more ZnS in ZSx with heterojunctions between ZnS and ZnO and throughout the bulk; tunable ZnS crystallite size and textural properties are an added advantage. The amount of ZnS in ZSx can be varied by simply changing the thiourea content. Although ZnO and ZnS are wide band gap semiconductors, ZSx exhibits visible light absorption, at least up to 525 nm. This demonstrates an effective reduction of the optical band gap and substantial changes in its electronic structure. Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and secondary-ion mass spectrometry results show features due to ZnO and ZnS and confirm the composite nature with heterojunctions. The above mentioned observations demonstrate the multifunctional nature of ZSx. Bare ZSx exhibits a promising sunlight-driven photocatalytic activity for complete mineralization of endocrine disruptors such as 2,4-dichlorophenol and endosulphan. ZSx also exhibits photocurrent generation at no applied bias. Dye-sensitized solar cell performance evaluation with ZSx shows up to 4% efficiency and 48% incident photon conversion efficiency. Heterojunctions observed between ZnO and ZnS nanocrystallites in high-resolution transmission electron microscopy suggest the reason for effective separation of electron–hole pairs and their utilization.

General strategy for embedding high quality Fe3O4 quantum dots and ZnS:Mn2+ quantum dots in a silica matrix

In this paper, ZnS:Mn2+ quantum dots (QDs) Fe3O4 quantum dots (QDs)/SiO2 nanocomposites were successfully synthesized by reverse microemulsion method. The average diameter of ZnS:Mn2+ QDs, Fe3O4 QDs and ZnS:Mn2+ QDs Fe3O4 QDs/SiO2 nanocomposites was about 5.8, 9 and 29 nm, respectively. As the mass ratio of ZnS:Mn2+ to Fe3O4 QDs increased from 2.5:4 to 7.5:4, the intensity of the yellow–orange emission coming from Mn2+ ions was increased. The superparamagnetic property of ZnS:Mn2+ QDs Fe3O4 QDs/SiO2 nanocomposites was observed at room temperature, and the saturation magnetization was decreased as the amount of ZnS:Mn2+ QDs increased.

The effect of ZnS segregation on Zn-rich CZTS thin film solar cells

Analysis of ZnS segregation behaviour and its influence on the device performance has been made on the Zn-rich Cu2ZnSnS4 thin film solar cells. Cross-sectional transmission electron microscopy images reveal that ZnS is the main secondary phase in the Cu2ZnSnS4 layer obtained from a sulphurised Zn/CuSn metallic stack. The excess Zn diffuses from back contact region to top surface of Cu2ZnSnS4 layer accumulating in the form of ZnS. The solar cell with a higher Zn concentration shows a large quantity of isolated ZnS grains at Cu2ZnSnS4 top surface which is close to CdS/Cu2ZnSnS4 heterojunction interface. Soft X-ray absorption spectroscopy indicates a large spike-like conduction band offset between Cu2ZnSnS4 and ZnS. Consequently, such much ZnS precipitates would increase series resistance and generate lower short-circuit current and external quantum efficiency. However, appropriate amount of ZnS at the space charge region of the solar cell has beneficial effects by reducing the heterojunction interface recombination. Therefore, an improved open-circuit voltage and a higher shunt resistance are achieved. This paper provides a possible method to intentionally segregate ZnS at the space charge region by depositing the Zn layer at the bottom of co-sputtered CuSn layer. Although it is difficult to synthesis a pure phase Cu2ZnSnS4 absorber, we can utilise the ZnS secondary phase to improve the Cu2ZnSnS4 solar performance by controlling the Zn-excess amount.

The Tribological Chemistry of the Oil Blends of Zinc Dialkyldithiophosphate with 2-Mercaptobenzothiazole Derivatives

X-ray absorption near-edge spectroscopy at the phosphorous and sulfur edges was used to identify the chemical species in thermal films and antiwear films on the macroscale. For the thermal films, it was found that the introduction of the additive MBTT/MBTA to the base oil, zinc dialkyldithiophosphate (ZDDP), tended to retard the formation of the polyphosphate, and has no effect on the thickness of the films. The topmost surface thermal films may be mainly comprised of some new compounds generated from the interaction of ZDDP with the antiwear additives MBTT/MBTA, along with a small amount of unchanged ZDDP, the sub-surface, and the bulk were mainly comprised of Zn phosphate, along with an amount of ZnS. For the antiwear films, the introduction of the additive MBTT/MBTA to the base oil, ZDDP, reduces the chain length of polyphosphate, which the N-containing decomposed products of 2-mercaptobenzothiazole derivatives are responsible for. It is very clear that MBTT or MBTA has indeed interacted with ZDDP to form new phosphate in the overall antiwear films. The topmost surface antiwear films were mainly comprised of short-chain polyphosphate, the sub-surface and the bulk may be mainly comprised of Zn phosphate and ZnS.

Relaxor Ferroelectric Polymers–Fundamentals and Applications

We present recent studies in the fundamentals and applications of the relaxor ferroelectric polymers, i.e., Poly(vinylidene fluoride-trifluroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE) terpolymers and high energy electron irradiated P(VDF-TrFE) copolymers. We show that the dynamic processes in these relaxor ferroelectric polymers are very similar to these observed in various polar-glasses. We further show that the large and reversible polarization change in these polymers leads to giant electrostriction and large electro-optic effect. By employing active electric boundary conditions, we demonstrate that the large electromechanical responses in these electroactive polymers can be made use of effectively for energy harvesting with high harvested electric energy density and efficiency. Terpolymer composites with ZnS nanoparticles provide an advanced E-O polymer which refractive index can be varied widely by small amount of ZnS in the composites while maintaining the large E-O effect of the matrix.

Synthesis and Characterization of Nanosized ZnS Confined in Ordered Mesoporous Silica

Nanosized ZnS has been prepared inside MCM-41 hosts by two related schemes, both of which are derived from surface modification methods. The ZnS-containing MCM-41 samples with and without the functional groups (ethylenediamine groups in this case) were designated as ZnS−ED−MCM-41 and ZnS−MCM-41(cal), respectively. The ZnS−MCM-41 composites were characterized by powder X-ray diffraction patterns, transmission electron microscopy, energy disperse spectra, N2 adsorption−desorption isotherms, UV−vis diffuse reflectance spectra, and photoluminescence (PL) spectra. The ZnS was mainly formed and retained in the channels of the MCM-41 host, and its growth was controlled by the channels. In contrast, the amount of ZnS on the external surface is much smaller. The existence of ZnS inside the MCM-41 hosts resulted in a considerable decrease in surface area, pore diameter, and pore volume, and a massive blue shift in the UV−vis spectra was observed. In comparison with the ZnS−MCM-41(cal) sample, a dramatic increase in...

Sandwich colloids of zinc oxide and zinc sulfide in aqueous solutions

Colloid particles, composed of ZnO and ZnS particles in contact or ZnO colloid particles coated with ZnS, have been investigated. The effect of various amounts of ZnS on the ZnO visible emission was studied. The results show that ZnS quenches the ZnO visible emission by hole transfer; however, fast recombination between the electron and hole takes place at the ZnO-ZnS interface. This is reflected by a decrease in the yield of reduction of methyl viologen upon addition of ZnS to the ZnO-methyl viologen system.

Sintering behaviour and electrical properties of Cd1?xZnxS films containing CdCl2

Polycrystalline Cd1−x Zn x S films were prepared by coating a slurry which consisted of CdS, CdCl2,, various amounts of ZnS and propylene glycol on to glass substrates and by sintering in a nitrogen atmosphere, and their sintering behaviours and electrical properties were investigated. As the amount of ZnS increases, the enhancing effects of CdCl22 on sintering and doping decrease, due primarily to the formation of ZnCl2 which evaporates rapidly during sintering, resulting in poor microstructure and a sharp increase in electrical resistivity. The sharp increase in the electrical resistivity is related to a sharp decrease in electron concentration which is caused by poor doping efficiency, and by an increase in the donor ionization energy of chlorine as the zinc content increases. The trap density of grain boundaries, on the other hand, decreases with increasing zinc content in sintered Cd1−x Zn x S films.[/p]

Photogeneration of hydrogen from water over an alumina-supported ZnS–CdS catalyst

The rate of hydrogen generation from water with an alumina-supported mixed semiconductor catalyst (ZnS–CdS/Al2O3) has been found to be much higher than those from water with singly supported catalysts (ZnS/Al2O3 and CdS/Al2O3) under irradiation by both u.v. and visible light. The activity is not improved by the physical mixture of these singly supported catalysts even when the amounts of ZnS and CdS are the same as those present in the ZnS–CdS/Al2O3. The significant improvement in the rate of hydrogen production over ZnS–CdS/Al2O3 catalyst is attributed to the intimate contact between ZnS and CdS particles that results from the deposition of fine ZnS particles over the CdS surface. Sites for hydrogen production seem to be newly generated on these contacting regions.

PHOTOGENERATION OF HYDROGEN FROM WATER WITH MIXED SEMICONDUCTOR CATALYST

Abstract Alumina-supported mixed semiconductor catalyst, ZnS·CdS/Al2O3, showed a significant rate of hydrogen generation from water under UV irradiation without an assistance of any noble metals. Singly supported catalyst, ZnS/Al2O3 or CdS/Al2O3, showed, however, less activity for photogeneration of hydrogen. The activity was not improved by physical mixture of ZnS/Al2O3 and CdS/Al2O3 although the amount of ZnS and CdS were the same as those in the ZnS·CdS/Al2O3 catalyst. This indicates that the intimate contacts between ZnS and CdS particles are necessary to photogeneration of hydrogen.

ChemInform Abstract: PHOTOCHEMICAL PRODUCTION OF HYDROGEN WITH ZINC SULFIDE SUSPENSIONS

AbstractBestrahlt man Suspensionen von ZnS‐Pulvern geeigneter Qualität in verschiedenen Elektrolytlösungen (S2′, S05" , S2′ + 80%′ , S2" + HzPOf ), wird H2 in Quantenausb.

Photochemical production of hydrogen with zinc sulfide suspensions

Hydrogen has been produced efficiently by the irradiation of suspensions of metalized ZnS powders in the presence of hole scavengers such as S/sup 2 -/ and SO/sub 3//sup 2 -/ions, mixtures of these two, or S/sup 2 -/ and hypophosphite ions. Results of investigation of the properties of active ZnS photocatalysts, the reaction parameters, and the formation of the reaction products are reported. The rate of the reaction was found to be strongly dependent on the amount of ZnS, and ZnS produced 5 times as much hydrogen as CdS.