Experimental exploration and DFT analysis of the kinetics and mechanism of malachite green photodegradation catalyzed by polyaniline-copper oxide nanocomposite.

CONTEXT AND RESULTS: A nanocomposite photocatalyst consisting of polyaniline (PANI) and copper oxide (CuO) was successfully synthesized through an in-situ polymerization approach using aniline as the precursor. The synthesized nanocomposite was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV-Vis), determination of the point of zero charge (pHPZC), and scanning electron microscopy (SEM). The photocatalytic efficiency of the PANI-CuO nanocomposite was evaluated in the context of photodegrading Malachite Green (MG) dye under visible light. Malachite Green, a synthetic dye commonly used in the textile and aquaculture industries, is a significant contaminant due to its toxic, mutagenic, and carcinogenic properties, making its removal from water resources crucial for environmental and human health. Distilled water artificially contaminated with MG dye was used as the medium for testing. The parameters influencing the photodegradation efficiency were comprehensively investigated. These parameters included catalyst dosage, reaction time, initial dye concentration, and pH. The results of this study indicate that the degradation efficiency of MG dye displayed an upward trend with time, catalyst dosage, and pH while exhibiting a converse relationship with the initial dye concentration. A degradation rate of 97% was achieved with an initial concentration of 20 mg L-1, employing a catalyst dose of 1.6 g L-1 at pH 6 for a reaction time of 180 min. Furthermore, the reusability of the catalyst was assessed, revealing consistent performance over five consecutive cycles. COMPUTATIONAL AND THEORETICAL TECHNIQUES: Density functional theory (DFT) was employed to optimize the structures of PANI, PANI-CuO, and their respective complexes formed through dye interaction, employing Gaussian software. These calculations employed the B3LYP/6-311G + + (d,p) basis set in an aqueous environment with water serving as the solvent. The kinetics of Malachite Green degradation were analyzed using both first and second-order kinetic models.

Pressure effect on the physical, mechanical, and thermal properties of ternary halide perovskite AgCaCl3: a first-principles study.

CONTEXT AND RESULTS: As an inorganic halide perovskite material, AgCaCl3, characterized by its high stability and environmental friendliness, is considered a potential candidate for major applications in optoelectronics and lens manufacturing. This work aimed to determine the electronic properties such as density of state (DOS) and band structure (BS) of AgCaCl3. The results showed that the material has an indirect band gap almost invariably at 1.5 eV in the pressure range studied. The dielectric function [Formula: see text], absorption coefficient [Formula: see text], optical conductivity [Formula: see text], reflectivity [Formula: see text], and the refractive index [Formula: see text] showed clearly that the perovskite AgCaCl3 preserved its optical characteristics within the chosen pressure range investigated. The calculated elastic constants C11, C12, and C14 as dynamic stability criteria for the elastic moduli such as bulk modulus (B), shear modulus (G), Young's modulus (Y), Poisson's ratio ([Formula: see text]), and anisotropy factor (A) showed that the material is a ductile plastic. Debye temperature ([Formula: see text]), isobaric and isochoric heat capacities (CP, CV), coefficient of the thermal expansion (α), Gibbs free energy (G), and entropy (S) were also studied. The results obtained provide a theoretical basis for experimental work and offer the possibility of future industrial applications of AgCaCl3. COMPUTATIONAL AND THEORETICAL TECHNIQUES: Density functional theory (DFT) calculations as implemented in the Wien2K code were used to study the mechanical and thermal properties of AgCaCl3 perovskite over a pressure range. Lattice parameters, electronic, and optical properties are optimized with the approximation of the generalized gradient of the Perdew-Burke-Ernzerhof function (PBE-GGA) function. The mechanical and thermodynamic properties were calculated using ElaStic and Gibbs2 codes, and the properties of AgCaCl3 over the pressure range investigated were predicted.

Development of a Hydrophobic Carbon Sponge Nanocomposite for Oil Spill Cleanup.

Oil leaks (or spills) into the aquatic environment are considered a natural disaster and a severe environmental problem for the entire planet. Samples of polyurethane (PU) composites were prepared with high specific surface area carbon nanotubes (CNT) to investigate crude oil sorption. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), density measurements, and mechanical compression tests were used to characterize the polyurethane-carbon PU-CNT prepared samples. The spongy composites exhibited good mechanical behavior and a contact angle of up to 119°. The oleophilic character resulted in increased hydrophobicity, a homogeneous oil distribution inside the sponge, and a sorption capacity in a water/oil mixture of 41.82 g/g. Stress-strain curves of the prepared samples showed the good mechanical properties of the sponge, which maintained its stability after more than six sorption desorption cycles. The CNT-PU composites may prove very effective in solving oil pollution problems.