FEG-SEM Analysis Research Articles

Cationic Imidazolium-Urethane-Based Poly(Ionic Liquids) Membranes for Enhanced CO2/CH4 Separation: Synthesis, Characterization, and Performance Evaluation.

The escalating emissions of CO2 into the atmosphere require the urgent development of technologies aimed at mitigating environmental impacts. Among these, aqueous amine solutions and polymeric membranes, such as cellulose acetate and polyimide are commercial technologies requiring improvement or substitution to enhance the economic and energetic efficiency of CO2 separation processes. Ionic liquids and poly(ionic liquids) (PILs) are candidates to replace conventional CO2 separation technologies. PILs are a class of materials capable of combining the favorable gas affinity exhibited by ionic liquids (ILs) with the processability inherent in polymeric materials. In this context, the synthesis of the IL GLYMIM[Cl] was performed, followed by ion exchange processes to achieve GLYMIM variants with diverse counter anions (NTf2-, PF6-, and BF4). Subsequently, PIL membranes were fabricated from these tailored ILs and subjected to characterization, employing techniques such as SEC, FTIR, DSC, TGA, DMA, FEG-SEM, and CO2 sorption analysis using the pressure decay method. Furthermore, permeability and ideal selectivity assessments of CO2/CH4 mixture were performed to derive the diffusion and solubility coefficients for both CO2 and CH4. PIL membranes exhibited adequate thermal and mechanical properties. The PIL-BF4 demonstrated CO2 sorption capacities of 33.5 mg CO2/g at 1 bar and 104.8 mg CO2/g at 10 bar. Furthermore, the PIL-BF4 membrane exhibited permeability and ideal (CO2/CH4) selectivity values of 41 barrer and 44, respectively, surpassing those of a commercial cellulose acetate membrane as reported in the existing literature. This study underscores the potential of PIL-based membranes as promising candidates for enhanced CO2 capture technologies.

The effect of ceramic YSZ powder morphology on coating performance for industrial TBCs

The increasing turbine inlet temperatures in modern gas turbines have raised concerns about the corrosion of ceramic thermal barrier coatings (TBCs) caused by molten silicate deposits, commonly referred to as “CMAS” due to their main constituents (CaO-MgO-Al2O3-SiO2). The objective of this study was to investigate the combined influence of powder morphology and chemical composition on the CMAS resistance and thermal cycling resistance of ceramic monolayer and bi-layer coatings created through Atmospheric Plasma Spraying (APS). Three powder morphologies were examined: porous Agglomerated and Sintered (A&S) granules, Hollow Spherical (HOSP) powders, and dense, irregular Fused and Crushed (F&C) particles. Monolayer 7-8YSZ coatings with both porous and dense vertically cracked (DVC) microstructures, and bi-layer coatings consisting of a bottom layer of porous standard 7-8YSZ and a top layer composed of a porous high‑yttrium ZrO2–55 wt% Y2O3 were obtained using all three powder types (A&S, HOSP, or F&C). Furthermore, the bi-layer systems were deposited with different ratios between the individual layer thicknesses and/or different total thickness. FEG-SEM, EDX, and micro-Raman analyses, were conducted to assess the coatings' performance. Nanoindentation high-speed mapping and pillar splitting test were performed to evaluate the mechanical behaviour. The study on 8YSZ monolayers shows that coatings from a F&C feedstock exhibit higher density, reducing the CMAS penetration. However, these coatings demonstrate poorer thermal cycling performance due to increased stiffness and thermal stresses. Coatings from HOSP and A&S powders allow CMAS penetration but offer stress relief pathways, enhancing the coating's ability to withstand thermal stresses. Bi-layer coatings with a 55YSZ top coat show superior CMAS resistance compared to 7-8YSZ monolayer coatings, with limited penetration causing top coat peeling. The thickness ratio between the layers also affects thermal cycling resistance, where a thinner 55YSZ layer extends the TBC lifetime.

Influence of ZnO nanoparticles on the properties of biodegradable PBAT matrix for food packaging application

Currently, the use of biodegradable polymers for packaging application has been an imperative topic due to the environmental damage caused by non-biodegradable materials. In the present study, PBAT/ZnO biodegradable nanocomposites were prepared by melt processing and characterized by FEG-SEM, DSC, XRD, TDNMR and water activity analysis. The main results showed an increase in the Tc values for all produced formulations, indicating a change in the crystalline profile of the PBAT, which was corroborated by XRD results. FEG-SEM showed that the systems containing up to 1 wt.% of ZnO showed better nanoparticles dispersion, while formulations containing 3 and 5 wt.% of ZnO presented large aggregates. TDNMR provided a more detailed assessment, showing that PBAT/ZnO systems containing 0.5 and 5 wt.% of ZnO presented a higher heterogeneity at molecular level. Finally, water activity analysis showed that ZnO addition promoted an increment in the biosafety levels compared to neat PBAT, making the PBAT/ZnO nanocomposites more promising for food packaging application.

Atmospheric Pressure Plasma Deposition of Hybrid Nanocomposite Coatings Containing TiO2 and Carbon-Based Nanomaterials

Among the different applications of TiO2, its use for the photocatalytic abatement of organic pollutants has been demonstrated particularly relevant. However, the wide band gap (3.2 eV), which requires UV irradiation for activation, and the fast electron-hole recombination rate of this n-type semiconductor limit its photocatalytic performance. A strategy to overcome these limitations relies on the realization of a nanocomposite that combines TiO2 nanoparticles with carbon-based nanomaterials, such as rGO (reduced graphene oxide) and fullerene (C60). On the other hand, the design and realization of coatings formed of such TiO2-based nanocomposite coatings are essential to make them suitable for their technological applications, including those in the environmental field. In this work, aerosol-assisted atmospheric pressure plasma deposition of nanocomposite coatings containing both TiO2 nanoparticles and carbon-based nanomaterials, as rGO or C60, in a siloxane matrix is reported. The chemical composition and morphology of the deposited films were investigated for the different types of prepared nanocomposites by means of FT-IR, FEG-SEM, and TEM analyses. The photocatalytic activity of the nanocomposite coatings was evaluated through monitoring the photodegradation of methylene blue (MB) as a model organic pollutant. Results demonstrate that the nanocomposite coatings embedding rGO or C60 show enhanced photocatalytic performance with respect to the TiO2 counterpart. In particular, TiO2/C60 nanocomposites allow to achieve 85% MB degradation upon 180 min of UV irradiation.

The effect of depositions parameters on the nanostructural and optical properties of CuPc organic thin films growth by oblique angle deposition CSP technique

Organic semiconductor CuPc thin films were deposited on different substrates with OAD CSP technique. The effects of substrate type, glancing angle and deposition temperature on surface and structural properties of CuPc thin films was reported in this study. The structural and morphological properties of CuPc thin films were investigated by XRD, RAMAN and FEG-SEM analysis. Dendritic nanostructures and nanoporous-straticulate sponge like structures were determined at surface area of CuPc thin films. XRD patterns showed that these CuPc thin films have orthorhombic α-phase structure with 2θ peak at 6.89˚, which is %100. The optical properties of all CuPc films which were determined from transmittance and reflectance measurements. The increasing of spray glancing angle and substrate temperature were decreased the UV-VIS absorption intensities at S-band and Q-band. However at 200 °C and 250 °C deposition temperatures at 45° spray glancing angle affected the Q-band absorption acerbically and red shift observed in here.

Enhanced exopolysaccharide production by multi metal tolerant Klebsiella variicolaSMHMZ46 isolated from mines area and application in metal bioremediation.

The current study aimed to enhance exopolysaccharide production by Klebsiella variicolaSMHMZ46 isolated from the Zawar mines area in Udaipur, Rajasthan, India, by optimizing the medium with OFAT and a central composite design. The trial including sucrose (9.5%), casein hydrolysate (3%), and NaCl (0.5%) yielded the maximum EPS production as indicated by applying the CCD-RSM biostatistical program. The composition of exopolysaccharides produced by Klebsiella variicolaSMHMZ46 culture was characterized. Growth under Pb(II), Cd(II), and Ni(II) metal amended conditions induced EPS production relative to control. TLC was used for identifying the sugar residues of EPS, in addition to determination of both total carbohydrate and protein contents. According to FT-IR analysis, EPS can interact with metal ions via their functional chemical groups, thereby supporting their bioremediation potential. The metal removal efficiency of bacteria and their produced EPS in broth individually spiked with Pb(II), Ni(II), and Cd(II) was 99.18%, 97.60%, and 98.20%, respectively, and powdered EPS from contaminated water was 85.76%, 72.40%, and 71.53%, respectively. According to FEG-SEM observations, the surface morphology of EPS becomes rough, demonstrating sharp bumps after metal binding. A FEG-SEM analysis of the structure of EPS was performed; the surface structure of EPS (with metal) was more rigid than that of control EPS (without metal). The interaction between the EPS system and Pb(II) ions was investigated using FEG-SEM coupled with energy dispersive X-ray spectra, and a strong peak of C, O, and Pb elements was observed, indicating successful Pb adsorption. These findings suggest that EPS from Klebsiella variicolaSMHMZ46 has a good metal adsorbing nature and could be a promising biosorbent for metal bioremediation of contaminated water.

Gum Arabic capped Cu/Zn bimetallic nanoparticles for the germination and growth of chickpea

Taking a note on the use of Cu and Zn in plant growth, in the present study, Gum Arabic (GA) capped Cu/Zn bimetallic nanoparticles (Cu/Zn@GA) Nps have been crafted by chemical reduction method. The Cu/Zn@GA Nps were extensively characterized by Uv–vis, FT-IR, FEG-SEM, EDX and HR-TEM analyses. The formation of Cu/Zn@GA Nps was evidenced by observation of SPR peak at 579 nm. The HR-TEM study revealed that Cu/Zn@GA Nps have an average particle size of ∼ 6 nm. The germination and growth of chickpea plant was studied under the influence of Cu/Zn@GA Nps where it behaved as an efficient plant-growth regulator. The effect of Cu/Zn@GA Nps on the germination percentage (100%), mean germination time, germination rate index, shoot length, count of number of leaves and branches, plant biomass and chlorophyll content of chickpea plants were studied. In different sets of experiments, concentration of Cu/Zn@GA Nps was varied (0.5%, 1%, 2% and 5% v/v) and the growth trend of chickpea plants was monitored for 20 days. The plant showed best germination and growth under the influence of 1% (v/v) concentration of Cu/Zn@GA Nps.

Production of Nano Hydroxyapatite and Mg-Whitlockite from Biowaste-Derived products via Continuous Flow Hydrothermal Synthesis: A Step towards Circular Economy.

Biowastes from agriculture, sewage, household wastes, and industries comprise promising resources to produce biomaterials while reducing adverse environmental effects. This study focused on utilising waste-derived materials (i.e., eggshells as a calcium source, struvite as a phosphate source, and CH3COOH as dissolution media) to produce value-added products (i.e., calcium phosphates (CaPs) derived from biomaterials) using a continuous flow hydrothermal synthesis route. The prepared materials were characterised via XRD, FEG-SEM, EDX, FTIR, and TEM analysis. Magnesium whitlockite (Mg-WH) and hydroxyapatite (HA) were produced by single-phase or biphasic CaPs by reacting struvite with either calcium nitrate tetrahydrate or an eggshell solution at 200 °C and 350 °C. Rhombohedral-shaped Mg-WH (23-720 nm) along with tube (50-290 nm diameter, 20-71 nm thickness) and/or ellipsoidal morphologies of HA (273-522 nm width) were observed at 350 °C using HNO3 or CH3COOH to prepare the eggshell and struvite solutions, and NH4OH was used as the pH buffer. The Ca/P (atomic%) ratios obtained ranged between 1.3 and 1.7, indicating the formation of Mg-WH and HA. This study showed that eggshells and struvite usage, along with CH3COOH, are promising resources as potential sustainable precursors and dissolution media, respectively, to produce CaPs with varying morphologies.

Deep cryogenic treatment of AA7050: tensile response and corrosion susceptibility

Cryogenic treatments represent an innovative technology developed with the aim of improving the performance of metallic alloys. The beneficial effects on steels are well documented in the literature, whereas their influence on other materials, such as aluminum alloys, is still not completely clarified. Even if the scientific literature reports conflicting data and conclusions, the industrial applications of such treatments are constantly growing. In the present experimental work, the mechanical and corrosion properties of a high-performance 7050 aluminum alloy plate were studied after cryogenic treatment at − 196 °C in liquid nitrogen. Tensile tests were performed on heat-treated samples, and intergranular corrosion tests were carried out on prismatic samples, according to ASTM G110-92 standard. The specimens were exposed to the corrosive environment and the effect of intergranular corrosion was measured by quantitative analysis using light-optical microscopy (LOM). Whereas trifling variation was observed in the mechanical resistance and plastic behavior, the corrosion tests showed a benefic effect of the cryogenic treatment. The microstructure was investigated by FEG-SEM analysis, revealing a different distribution of precipitates near the grain boundaries, which was able to reduce the electrochemical potential difference among these regions and the center-grain.

Effect of non-thermal atmospheric pressure plasma and ErCr:YSGG LASER activation of three fluoride varnishes on surface re-mineralization of enamel: A SEM-EDX analysis.

Dental remineralization is the process of transporting minerals from the surrounding environment (i.e., saliva and biofilm) into partially demineralized tooth structures. Remineralization can be induced by professional therapies such as fluoride-based treatments that have the highest level of supporting evidence. High-intensity LASER and nonthermal atmospheric pressure plasma therapy have been known to increase the resistance of enamel to demineralization by surface modification. The aim of the study was to evaluate and compare the surface remineralization of enamel using ErCr:YSGG LASER and nonthermal atmospheric pressure plasma (NTP) activation with three different fluoride varnishes. Sixty-eight extracted premolars were used which were sectioned mesiodistally to obtain 135 specimens and artificial caries were induced on the experimental surface. They were then randomly divided into three groups (n = 45): MI Varnish (GC Japan), Vanish Varnish (3M ESPE), and Embrace Varnish (Pulpdent). After varnish application, these groups were further divided into three subgroups based on the activation therapy used. Fifteen samples from each group were treated with ErCr:YSGG LASER, 15 samples with NTP, and 15 samples were the control that did not undergo activation. After 9 days of pH cycling, the mean ion concentration of the surface calcium and phosphate ions was recorded using FEG-SEM and EDX analysis. The data were statistically analyzed. One-way ANOVA and post hoc Tukey test accepting P < 0.05 were performed for comparisons between all analyses groups. Vanish Varnish showed a higher Ca/P ratio in LASER, NTP, and control subgroups, followed by MI Varnish and Embrace Varnish. ErCr:YSGG LASER therapy showed an improved Ca/P ratio in all varnishes than NTP therapy and control. ErCr:YSGG LASER therapy showed positive effects toward improving the Ca/P, followed by NTP therapy as compared to control in all three varnishes indicating their role in enhancing the effects of remineralization. Vanish Varnish showed a higher Ca/P ratio indicating better remineralization post activation.

Comparative evaluation of bioactivity, fluoride release, shear bond strength, and compressive strength of conventional glass ionomer cement incorporated with three inorganic bioactive nanoparticles: An experimental analysis.

Over the course of four decades, the bioactive materials have changed. They have become more specialized, more manageable, possessing superior qualities. Thus, it should be encouraged to conduct ongoing research to improve these materials even further in order to meet the growing clinical and restorative needs. To evaluate and compare bioactivity, fluoride release, shear bond strength and compressive strength of conventional GIC incorporated with three inorganic bioactive nanoparticles. For the study, total of 160 samples were included. The samples were divided in four groups (40 samples per group) i.e. 3 wt% of forsterite (Mg2SiO4) (Group 2), wollastonite (CaSiO3) (Group 3) and niobium pentoxide (Nb2O5) (Group 4) nanoparticles incorporated into GIC (Group 1). The bioactivity (FEG-SEM and EDX analysis), fluoride release (ion-selective electrode), shear bond strength testing (UTM followed by evaluation under stereomicroscope) and the compressive strength (UTM) was checked for each group. Wollastonite nanoparticles (3wt %) incorporated to GIC showed maximum increase in the apatite crystal formation,Ca and P content and highest fluoride release. Mean shear bond strength was highest in niobium pentoxide nanoparticles (3wt %) incorporated to GIC while mean compressive strength was highest in forsterite nanoparticles (3wt %) added to GIC. Positive results were observed which showed increase in the bioactivity alongwith enhancement of the fluoride release, shear bond strength and compressive strength but further research on these materials is warranted before its use in clinical practice.

Blue-red emitting materials based on a pyrido[2,3-b]pyrazine backbone: design and tuning of the photophysical, aggregation-induced emission, electrochemical and theoretical properties.

Pyrido[2,3-b]pyrazine-based donor–acceptor–donor (D–A–D) molecules were designed by altering donor amines and synthesized using the Buchwald–Hartwig C–N coupling reaction. Further, the tunable opto-electrochemical properties of the dyes were studied in detail. The dye possesses intramolecular charge transfer (ICT) transition (412–485 nm), which marked the D–A architecture and induces a broad range of emissions from blue to red (486–624 nm) in the solution and solid state. Some of the dyes show aggregation-induced emission (AIE) features and formation of nanoparticles in the THF/H2O mixture, as confirmed by DLS and FEG-SEM (of 7) analysis. The AIE characteristics indicate its solid/aggregate-state application in organic electronics. The molecules exhibit high thermal stability, low band gap (1.67–2.36 eV) and comparable HOMO (−5.34 to −5.97 eV) and LUMO (−3.61 to −3.70 eV) energy levels with those of reported ambipolar materials. The relationship between the geometrical structure and optoelectronic properties of the dyes, as well as their twisted molecular conformation and small singlet and triplet excitation energy difference (ΔEST = 0.01–0.23 eV) were analyzed using the DFT/TDDFT method. Thus, potential applications of the dyes are proposed for optoelectronic devices.

Ultrasound-assisted synthesis of NiO nanoparticles and their catalytic application for the synthesis of trisubstituted imidazoles under solvent free conditions

The present protocol reports the ultrasound assisted synthesis of NiO nanoparticles(NPs) using benzylamine as a base and different types of cyclodextrins (CDs) as capping agents. The use of α-CD, β-CD or γ-CD leads to different morphologies of NiO NPs. In particular, NiO nanosheets obtained using β-CD as the capping agent. The synthesized NPs were characterized by FEG-SEM, TEM, XRD and EDS analysis. They showed high catalytic activity towards synthesis of different trisubstituted imidazoles under solvent free conditions. In addition, NiO NPs could be recycled and reused consecutively up to four recycle runs without much loss of their catalytic activity.

Evaluation of the root filling quality with experimental carrier-based obturators: a CLSM and FEG-SEM analysis.

This study evaluated tubule penetration of GuttaFlow Bioseal with cold single cone or carrier-based technique, under confocal laser scanning microscopy (CLSM). Twenty straight single-rooted teeth were instrumented with Hyflex CM and divided in two groups (n = 10) according to the obturation method: single cold gutta-percha cones; experimental carrier-based obturators. GuttaFlow Bioseal, labelled with Rhodamine B dye, was used as sealer in both groups. Teeth transversally sectioned were observed under CLSM. Percentage of sealer penetration and integrity of sealer layer perimeter were measured. Surface and microstructural characteristics of obturators and gutta-percha cones were compared by FEG-SEM and EDX analysis. No significant differences were found between groups for each examined parameter. Significant differences (P < 0.05) were reported mainly within groups. Integrity was similar among and within groups. FEG-SEM/EDX analysis of obturators revealed the presence of Ba and Zn. Carrier-based obturation technique associated with GuttaFlow Bioseal does not seem to affect sealer penetration into dentinal tubules.

Microbial activity and studies on excavated megalithic micaceous potsherds from Peninsular India

The abundantly available mica flakes were added in raw materials to manufacture pottery in Central Peninsular India during the early Iron Age (700-300 BCE) for storage and glittering. The micaceous potsherds from the excavated megalithic site of Nagpur were studied for their composition, manufacturing techniques, microstructural features, microbial colonization, and estimation of firing temperature. The analytical techniques used were micro-XRF, FTIR, XRD, FEG-SEM, mercury porosimetry (MIP), and thermal analysis. The XRF and SEM-EDX data revealed that the potteries were coated with aqueous iron oxide on either surface for red hue and subsequently fired at an estimated temperature of 700-750 °C in a reducing atmosphere as determined by vibrational and mineralogical analysis. The X-ray microscopy and FEG-SEM images showed a grey color sandwich layer representing the original clay composition between iron oxide-coated red surface layers. MIP showed that the fine ware had a high porosity of 21-26% with a void ratio (e) of 0.28-0.36. The loosely adhered mica flakes influenced the strength and stability of the pottery. The 16S rRNA gene sequencing identified the presence of Bacillus velezensis within the round and elongated pits within the potsherds drawing nutrients from minerals.

Enhanced adsorptive removal of toxic anionic dye by novel magnetic polymeric nanocomposite: optimization of process parameters

The novel magnetic manganese ferrite/polyaniline nanocomposite (MnFe2O4-PANI-NC) was prepared for eradication of toxic anionic methyl orange (MO) dye from wastewater at almost neutral pH condition by impregnating polyaniline onto manganese ferrite. The characterization properties of MnFe2O4-PANI-NC was found by XRD, FEGSEM, TEM, FTIR, VSM, and BET analysis to analyze the adsorption process. The MO dye removal efficiency by sono-assisted adsorption was found to be 90.03% at solution pH 6.0 and sonication time 15 min, whereas the batch stirring and shaking gives the MO dye removal of ∼65% to ∼74% at same experimental condition. The adsorption kinetics followed pseudo-second order kinetics model with additional effect of intra-particle diffusion. The linear fitting of isotherm model followed Langmuir isotherm with equilibrium adsorption capacity of 175.44 mg/g at room temperature. The MO dye adsorption mechanism onto MnFe2O4-PANI-NC can be described by the synergistic effect of electrostatic interaction and π–π dispersive bonding between anionic MO dye molecules and positively charged MnFe2O4-PANI-NC surface. The central composite design (CCD) predicts the maximum MO dye removal of 99.01% at optimum condition of sonication time 14 min, MnFe2O4-PANI-NC dose 0.5 g/L and initial methyl orange (MO) dye concentration 10.0 mg/L. The MnFe2O4-PANI-NC is found to be stable even after 5th consecutive cycle of adsorption-desorption without compromising its adsorptive potential. Thus the fabricated MnFe2O4-PANI-NC can be a potential adsorbent material for sono-assisted removal of MO dye for large scale application due to less dependency on solution pH, facile fabrication technique, and rapid as well as decent dye uptake capacity.

Nanocomposite powders of hydroxyapatite-graphene oxide for biological applications

The repair of bone fractures is a clinical challenge for patients with impaired healing, such as osteoporosis. Currently, different strategies have been developed to design new biomaterials, enhancing their interactions with biological systems and conducting the cellular behavior in the desired direction to help fracture healing. In the present work, hydroxyapatite-graphene oxide (HA-GO) nanocomposites were produced and the morphological and physicochemical influences of the addition of 0.5 wt%, 1.0 wt% and 1.5 wt% of GO to HA were observed. FEG-SEM and TEM analyses of HA-GO nanocomposites showed HA nanoparticles adhered to the surface of the GO sheets, suggesting an effective method to form nanostructured graphene-based biomaterials. As confirmation, physicochemical analyses by Raman, FTIR and TGA demonstrated a strong affinity between HA and GO, according to the increase of concentration from 0.5 wt% to 1.5 wt% GO in the HA-GO nanocomposites. Also, in order to evaluate the HA-GO nanocomposites behavior under biological microenvironment, in vitro bioactivity and indirect cytotoxicity tests were performed. FEG-SEM analyses confirmed the positive results for the bioactivity properties of HA-GO nanocomposite and indirect cytotoxicity demonstrated that even with a decrease in the hDPSCs viability and proliferation, when increasing to 1.5 wt% of GO concentration, high level of cell viability was exhibited by HA-GO nanocomposites. These biological results suggested the 0.5 wt% HA-GO nanocomposite as a potential bioactive bone graft and a promising biomaterial for bone tissue regeneration, when compared to the pure HA.

Well dispersed CeO2@HNTs nanofiller in the poly (vinyl chloride) membrane matrix and enhanced its antifouling properties and rejection performance

Cerium oxide (CeO2) is an effective agent against a variety of bacterial strains and helps in preventing bacterial attachment on the surface of the membrane. CeO2 loaded halloysite (HNTs) nanofiller were synthesized using the co-precipitation method. After that CeO2@HNTs nanofiller embedded Poly(vinyl chloride) (PVC) ultrafiltration membranes were also prepared and investigated by XRD, FEG-SEM, EDX, TEM, HRTEM and SPM analysis. The result shows that hydrophilicity of the membrane was enhanced from 91.3° to 74.1° and M0 (no nanofiller) average pure water flux was around 127.33 L m−2 h−1. After addition of 2 wt.% nanofiller (M2) pure water flux increases up to 206.42 L m−2 h−1 which was around 79 % increment. Flux recovery ratio also enhanced from 68.9 % to 94.2 %. Furthermore, EDX mapping, results confirm that CeO2@HNTs was homogeneously well distributed in the membrane matrix. Humic acid (HA) rejection of the prepared membrane also improved up to 97.9 % by 2 wt% CeO2@HNTs addition. The concentration of nanofiller added plays a crucial role in membrane properties and hence an optimum concentration selected for fabrication of efficient antifouling membrane.

Temperature-Time profile effects on evolution of physical and electronic properties in visible light Cu2CoSnS4 photodetectors

Earth-abundant quaternary chalcogenide Cu2CoSnS4 (CCTS) films on soda-lime glass (SLG) substrates are prepared via non-vacuum, cost-effective direct solution spin coating technique. The phase formation mechanism of CCTS films is investigated via TGA, FTIR, XRD, and RAMAN characterization. Annealing temperature effects on the crystalline phase, chemical composition, and grain growth, strongly linked with electrical and photodetection parameters of CCTS films, are systematically investigated through XRD, Raman, FEG-SEM, and EDS analysis. Through the transfer length measurement (TLM) method, the electrical properties of CCTS films annealed at 575 °C exhibit noticeable 92% reduction of both contact resistance (Rc) and resistivity (ρ), compared to those of the film processed at 300 °C. The highest photoresponsivity (7.50 A/W) and specific detectivity (4.70 × 1010 Jones) of CCTS devices have been demonstrated with annealing conditions at 575 °C and a bias voltage of 10 V as well. The present study reveals the impact of both annealing temperature and bias voltage on photodetector performance.

Cu dispersed TiO2 catalyst for direct hydrogenation of carbon dioxide into formic acid

The exponential increase in CO2 emission enforced the discovery of alternative methods to curb excessive atmospheric CO2. In the present manuscript, nano-crystalline copper disperced TiO2 (CuOx-TiO2) catalyst has been explored for the direct hydrogenation of CO2 into formic acid (FA) under hydrothermal condition. Series of Cu based catalysts were synthesized via a simple co-precipitation method and tested for CO2 hydrogenation. Of the tested catalyst, CuOx-TiO2 showed the highest TON (turnover number) 6.62 for FA under non-stringent reaction conditions (40 bar, 200 °C). The addition of base (both organic/ inorganic) showed significant improvement in CO2 reduction. Inorganic bases showed a profound effect to obtain a higher yield of FA as compared to organic bases. The process intensification study was conducted for the influence of temperature, base, concentration of base, pressure, catalyst loading, and reaction time on FA production. The physicochemical properties of the synthesized catalyst were studied by using XRD, ATR-FTIR, BET, FEG-SEM, EDX, and ICP-OES analysis. Catalyst recyclability study showed the gradual drop in TON and TOF for five cycles but the easy regeneration process reboots the catalytic activity. The plausible reaction mechanism for direct hydrogenation of CO2 to FA has also been proposed.