Bimetallic sulfides embedded into porous carbon composites with tunable magneto-dielectric properties for lightweight biomass- reinforced microwave absorber

Currently, biomass-derived porous carbon materials have great potential for the development of advanced microwave absorbing materials (MAMs) with lightweight, high performance, wide effective bandwidth (EAB), and thin matching thickness. Herein, we reported low-cost, high-performance MAMs for the successful anchoring of Cu-based bimetallic sulfides CuCo₂S₄@CoS₂ on biomass porous carbon (BPC) derived from pistachio shells using a simple carbonization, hydrothermal, and electrostatic self-assembly method. The results demonstrate that the prepared BPC@CuCo₂S₄@CoS₂ composite exhibits excellent microwave absorption due to its balanced impedance matching and the combined effect of conductive loss, dipole polarization, interfacial polarization, dielectric loss, and magnetic loss. To be precise, the minimum reflection loss (RL_min) of BPC@CuCo₂S₄@CoS₂ reaches −64.2 dB at a packing load of 20 wt%, with an EAB of 6.6 GHz and a thickness of 2.3 mm. This work provides new insights into the study of copper-based bimetallic sulfide and BPC composites in MAMs.     

Synthesis and structural,microstructural and humidity sensing behavior of (x)rGo+(1-x)CoCr2O4 composite for humidity sensor applications

Immediate research is needed to determine why monolayer carbon atom (rGO) composites function so poorly as humidity sensors. Here, an attempt is made on (x)rGo+(1-x)CoCr₂O₄(x = 0,0.1,0.2 and 0.3) composite for humidity sensor. The method is straightforward, cheap, and basic, making it ideal for mass-producing (x)rGo+(1-x)CoCr₂O₄ composite. In this research, we investigate whether or not the (x)rGo+(1-x)CoCr₂O₄ composite can be used to improve the responsiveness of humidity sensors at ambient temperature. The use of X-ray diffraction allows for the investigation of crystallinity, phase, and structure (XRD). Crystallite size were estimated and found 9–11 nm. Morphology of the samples were seen ultrathin, wrinkled, paper-like, spherical type image. Samples were subjected to study the humidity sensing behavior. Within the range of 11%–97% RH, CCR-most rGO's impressive sensing response was 92%. The compound's stability was evaluated over the course of three months, and its response time was found to be between 32 and 36 s. To illustrate the mechanism of humidity sensing, we will use the stages of an adsorption process. For x = 0.3 concentration we observed high sensing response.     

Microwave drying method investigation for the process and kinetics of drying characteristics of high-grade rutile TiO2

Titanium dioxide has been extensively applied in aviation, cosmetics, the chemical industry, and coatings. Currently, the primary way to prepare high-grade rutile TiO₂ is the chlorination method, which mainly uses ilmenite or titanium slag as raw material through the chlorination process and then reacts it in an oxidation furnace to prepare titanium powders. However, the TiO₂ material produced by the liquid-phase method contains a large amount of water, which makes the equipment vulnerable to corrosion in the subsequent process. Meanwhile, the sharp temperature change will lead to the accumulation of water vapor, which may lead to explosion and severe agglomeration, resulting in high research costs and reduced product performance. Therefore, drying equipment with high drying efficiency, high product quality, and low carbon is urgently needed. This paper used microwave drying equipment to assist in drying rutile TiO₂ powders. Results indicated that the microwave power, moisture content, and initial mass positively related to the drying rate. The drying process was simulated and analyzed using four common thin-layer kinetic models. A good agreement was that the Modified Page model was in good agreement with the actual drying process of TiO₂. The effective diffusion coefficient was calculated. After calculation, the activation energy of microwave-drying TiO₂ was 8.22 g/W. This article offers a kinetic theoretical basis and abundant data guidelines for actual products to reinforce the drying of high-grade TiO₂ powders.     

Preparation and in vitro assessment of economic bio-scaffolds modified with wollastonite (CaSiO3)

Porous bioceramic scaffolds are the preferred option for substituting spongy bone. Therefore, this study evaluates the use of carbonate associated with apatite rocks at Hamadat mines (referred to as calcite) as a source of low-cost bioactive material useful for biomedical applications. In this study, the depositional environment and mineralogical, and petrographic behavior of such depositions were studied. Furthermore, the possibility of producing highly porous, low-cost bioceramic scaffolds using the freeze-drying technique was demonstrated. The bioactivity of the produced scaffolds was enhanced by adding different ratios of wollastonite (25, 50 and 75 wt %) to the scaffold’s batches. However, the scaffolds were coated with ZnCl₂ to enhance their antimicrobial susceptibility. The physical and mechanical properties as well as the phase composition and microstructure of the prepared scaffolds were investigated. The X-ray diffraction results revealed the formation of pure phase of α-wollastonite after 3 h of sintering at 1200 °C. To estimate the scaffolds’ biodegradability, the pH and the weight change were measured. The results were confirmed using the inductively coupled plasma measurements for the scaffolds deposited in a simulated body fluid (SBF) solution for 28 days. Results showed that the scaffolds had excellent bioactivity, which was demonstrated by the appearance of apatite particles on their surface after being immersed in the SBF. The antimicrobial activity test revealed that Zn²⁺, NPs and CaSiO₃ had positive effects due to their oxidative stress process. Zn²⁺, Ca²⁺, and Si⁴⁺ cations can be adsorbed on bacterial surface membranes, interacting with the respiratory microbial enzymes, inhibiting their actions, and damaging the cell, thereby causing the bacterial cell decomposition.     

Catalytic oxidation of nitric oxide over modified carbide slag: Experimental and theoretical studies

In this work, experimental and theoretical methods were used to investigate the catalytic effect of K₂O on NO oxidation. Experimental results indicated that K₂O was the main active component. It enhanced the removal of NO and decreased the reaction temperature. Theoretical results indicated that the K₂O (001)-O surface was more suitable for the adsorption of NO and O₂. Also, NO and O₂ on the Ca(OH)₂ surface may migrate to the K₂O surface for reaction. NO₂ was formed via the interaction of (NO)₂ and O atoms. The formation of ON NO was the key step for NO oxidation, which was more conducive to the subsequent oxidation of NO.