Hydroxyapatite and ionic liquid coupled with hybrid membranes for toxic pollutant removal and remediation.

Access to clean water is the mandatory requirement for every living being to sustain life. So, membrane-based integrated approach of adsorption and separation technology has recently been preferred by scientists over other conventional techniques, for wastewater treatment. Current research focused on the synthesis of novel imidazolium (A1) based IL, which was further functionalized with hydroxyapatite (HAp; extracted from Labeo rohita scales), to create possible solutions towards environmental remediation. Cellulose acetate (CA) was used for the fabrication of three different ionic liquid membranes. All the synthesized products were characterized by FTIR, XRD and TGA. Two dyes of different nature, i.e., congo red (anionic) and crystal violet (cationic) were selected because of their highly toxic and carcinogenic effects, for batch adsorption experiments. Antibacterial activity of the synthesized membranes was also evaluated against S. aureus. Results of the study revealed that CA-HA1 1:2 acted as the best adsorbent towards the removal of crystal violet, exhibiting removal efficiency of 98% with the contact time of 24 h while in case of congo red adsorption, CA-HA1 (1:2) proved as prime adsorbent with the removal efficiency of 96% for the same preceding contact time. Considering the antibacterial character of the synthesized membranes, CA-A1 (1:1) emerged as very efficient antibacterial agent with the inhibition zone of 50 mm after 48 h. The overall behavior of monolayer and multilayer adsorption was witnessed for both dyes while kinetic studies favored the pseudo-second order reaction for all adsorbents.

Investigation of structural, electronic and optical properties of two-dimensional MoS2-doped-V2O5 composites for photocatalytic application: a density functional theory study.

In the present research, the structural, electronic and optical properties of transition metal dichalcogenide-doped transition metal oxides MoS2-doped-V2O5 with various doping concentrations (x = 1-3%) of MoS2 atoms are studied by using first principles calculation. The generalized gradient approximation Perdew-Burke-Ernzerhof simulation approach is used to investigate the energy bandgap (Eg) of orthorhombic structures. We examined the energy bandgap (Eg) decrement from 2.76 to 1.30 eV with various doping (x = 1-3%) of molybdenum disulfide (MoS2) atoms. The bandgap nature shows that the material is a well-known direct bandgap semiconductor. MoS2 doping (x = 1-3%) atoms in pentoxide (V2O5) creates the extra gamma active states which contribute to the formation of conduction and valance bands. MoS2-doped-V2O5 composite is a proficient photocatalyst, has a large surface area for absorption of light, decreases the electron-hole pairs recombination rate and increases the charge transport. A comprehensive study of optical conductivity reveals that strong peaks of MoS2-doped-V2O5 increase in ultraviolet spectrum region with small shifts at larger energy bands through increment doping x = 1-3% atoms of MoS2. A significant decrement was found in the reflectivity due to the decrement in the bandgap with doping. The optical properties significantly increased by the decrement of bandgap (Eg). Two-dimensional MoS2-doped-V2O5 composite has high energy absorption, optical conductivity and refractive index, and is an appropriate material for photocatalytic applications.

Correction: Al-Qhtani et al. Half Metallic Ferromagnetism and Transport Properties of Zinc Chalcogenides ZnX2Se4 (X = Ti, V, Cr) for Spintronic Applications. Materials 2022, 15, 55.

In the original publication [...].

Combustion Synthesis of High Density ZrN/ZrSi2 Composite: Influence of ZrO2 Addition on the Microstructure and Mechanical Properties.

In this study, a high-density ZrN/ZrSi2 composite reinforced with ZrO2 as an inert phase was synthesized under vacuum starting with a Zr-Si4N3-ZrO2 blend using combustion-synthesis methodology accompanied by compaction. The effects of ZrO2 additions (10-30 wt%) and compression loads (117-327 MPa) on the microstructure, porosity and hardness of the samples were studied. The process was monitored using XRD, SEM, EDS, porosity, density and hardness measurements. Thermodynamic calculations of the effect of ZrO2 addition on the combustion reaction were performed including the calculation of the adiabatic temperatures and the estimation of the fractions of the liquid phase. The addition of up to 20 wt% ZrO2 improved the hardness and reduced the porosity of the samples. Using 20 wt% ZrO2, the sample porosity was reduced to 1.66 vol%, and the sample hardness was improved to 1165 ± 40.5 HV at 234 MPa.

Hydrogen Generation over RuO2 Nanoparticle-Decorated LaNaTaO3 Perovskite Photocatalysts under UV Exposure.

The efficacy of LaNaTaO3 perovskites decoration RuO2 at diverse contents for the photocatalytic H2 generation has been explored in this study. The photocatalytic performance of RuO2 co-catalyst onto mesoporous LaNaTaO3 was evaluated for H2 under UV illumination. 3%RuO2/LaNaTaO3 perovskite photocatalyst revealed the highest photocatalytic H2 generation performance, indicating that RuO2 nanoparticles could promote the photocatalytic efficiency of LaNaTaO3 perovskite significantly. The H2 evolution rate of 3%RuO2/LaNaTaO3 perovskite is 11.6 and 1.3 times greater than that of bare LaNaTaO3 perovskite employing either 10% CH3OH or pure H2O, respectively. Interestingly, the photonic efficiency of 3%RuO2/LaNaTaO3 perovskite was enhanced 10 times than LaNaTaO3 perovskite in the presence of aqueous CH3OH solutions as a hole sacrificial agent. The high separation of charge carriers is interpreted by the efficient hole capture using CH3OH, hence leading to greater H2 generation over RuO2/LaNaTaO3 perovskites. This is attributed to an adjustment position between recombination electron-hole pairs and also the reduction of potential conduction alignment as a result of RuO2 incorporation. The suggested mechanisms of RuO2/LaNaTaO3 perovskites for H2 generation employing either CH3OH or pure H2O were discussed. The photocatalytic performances of the perovskite photocatalyst were elucidated according to the PL intensity and the photocurrent response investigations.

Half Metallic Ferromagnetism and Transport Properties of Zinc Chalcogenides ZnX2Se4 (X = Ti, V, Cr) for Spintronic Applications.

In ferromagnetic semiconductors, the coupling of magnetic ordering with semiconductor character accelerates the quantum computing. The structural stability, Curie temperature (Tc), spin polarization, half magnetic ferromagnetism and transport properties of ZnX2Se4 (X = Ti, V, Cr) chalcogenides for spintronic and thermoelectric applications are studied here by density functional theory (DFT). The highest value of Tc is perceived for ZnCr2Se4. The band structures in both spin channels confirmed half metallic ferromagnetic behavior, which is approved by integer magnetic moments (2, 3, 4) µB of Ti, V and Cr based spinels. The HM behavior is further measured by computing crystal field energy ΔEcrystal, exchange energies Δx(d), Δx (pd) and exchange constants (Noα and Noß). The thermoelectric properties are addressed in terms of electrical conductivity, thermal conductivity, Seebeck coefficient and power factor in within a temperature range 0-400 K. The positive Seebeck coefficient shows p-type character and the PF is highest for ZnTi2Se4 (1.2 × 1011 W/mK2) among studied compounds.

Synthesis of Vanadium Carbide by Mechanical Activation Assisted Carbothermic Reduction.

Vanadium carbide is known, for its hardness and other unique properties, as a refractory material. The synthesis of vanadium carbide is always associated with the utilization of expensive active metals, such as aluminum, calcium and magnesium, as a reducing agent to extract the vanadium metal from its corresponding oxide, followed by carbidization. The carbidization of reduced vanadium requires a complicated process and elevated temperature. Mechanical activation to synthesize vanadium carbide from its corresponding oxide and carbon source represents a promising, straightforward and less energy-intensive route. In the present study, vanadium carbide is synthesized by the carbothermic reduction of a mechanically activated mixture of V2O5 and carbon black as reducing agents without any additives. The reduction process is monitored by means of thermogravimetric analysis. The reduction products are characterized by X-ray diffraction and field emission scanning electron microscope. It is found that V8C7 with an average crystallite size of 88 nm can be synthesized from a V2O5-C mixture after milling for 15 h and further heating at 1050 °C for 1 h in an inert atmosphere.