In this study, we used density functional theory (DFT) and natural bond orbital (NBO) analysis to determine the structural, electronic, reactivity, and conformational features of 2,5,5-trimethyl-1,3,2-di-heteroatom (X) phosphinane-2-sulfide derivatives (X = O (compound 1), S (compound 2), and Se (compound 3)). We discovered that the features improve dramatically at 6-31G** and B3LYP/6-311+G** levels. The level of theory for the molecular structure was optimized first, followed by the frontier molecular orbital theory development to assess molecular stability and reactivity. Molecular orbital calculations, such as the HOMO–LUMO energy gap and the mapping of molecular electrostatic potential surfaces (MEP), were performed similarly to DFT calculations. In addition, the electrostatic potential of the molecule was used to map the electron density on a surface. In addition to revealing molecules’ size and shape distribution, this study also shows the sites on the surface where molecules are most chemically reactive.

This study reports experimental analyses of adsorption thermodynamics using the polymeric adsorbent surface, polyethersulfone (PES), with different molar ratios of ZnO nanoparticles. Fourier transform infrared (FTIR), X‐ray diffraction (XRD), and field emission scanning electron microscopy (FESEM) were performed to study the adsorbent structure and morphology. FTIR results showed that both PES and ZnO nanoparticles were successfully incorporated into the nanocomposite, while the XRD analysis showed that the crystal adsorbent characteristics did not change. FESEM of the ZnO exhibits the formation of aggregates in the form of small spherical grains, and the sizes were in the range of 45–65 nm. The effects of different parameters (contact time, pH, temperature, adsorbent dosage, and diazinon concentrations) were investigated to find the optimal conditions of the prepared adsorbents. The equilibrium data for diazinon adsorption onto PES and ZnO/PES were analyzed using the Langmuir, Freundlich, Temkin, Dubinin‐Radushkevich, Jovanovic, and Flory‐Huggins models. Based on the values of the correlation coefficient, Langmuir and pseudo‐second‐order were found to be the best‐fitting model. In addition, adsorption at different temperatures (288.15–303.15 K) was used to determine thermodynamic parameters such as free energy, enthalpy, and entropy changes. Finally, these results allow designing different processing units for pollution removal.

In this research, Aloe Vera leaf powder (OAMP) was modified with carboxylated carbon nanotubes (CNTs-COOH) and the prepared nanocomposite was used as a novel low cost adsorbent for the removal of cadmium ions from aqueous solutions. The prepared OAMP/CNTs-COOH nanocomposite was characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Energy-dispersive x-ray spectroscopy (EDS) and Brunauer–Emmett–Teller (BET) analysis. The influence of operation parameters such as initial concentration of adsorbate, adsorbent dosage, contact time and pH of the cadmium solution on the cadmium adsorption process was studied by response surface methodology (RSM) optimization. The solid phase extraction (SPE) using OAMP/CNTs-COOH based-adsorbent was performed for the pre-concentration and matrix separation and inductively coupled plasma–mass spectrometry (ICP-MS) detector was used for measurement of cadmium ions concentration. The empirical adsorption data were fitted by Langmuir isotherm model. The value of maximum adsorption capacity was 46.95 mg g⁻¹, indicating high efficiency of OAMP/CNTs-COOH nanocomposite in the adsorption process of Cd(II). The kinetic of the Cd(II) adsorption process was followed by Elovich kinetic model. The reported thermodynamic parameters designated that the adsorption of Cd(II) on the OAMP/CNTs-COOH was an endothermic and spontaneous process. The results revealed that OAMP/CNTs-COOH demonstrate enhanced adsorption performance in comparison with non-treated Aloe Vera.

Food hygiene must be observed in production, storage, supply, and sales to obtain healthy foods with desirable quality. The purpose of present study was to evaluate the awareness, attitudes, and practices of Tabriz University of Medical Sciences food services staff toward food hygiene. A questionnaire consisting of 46 questions was completed by 40 food services staff from February to March 2019. Based on the results, respondents had an acceptable awareness (92.5% to 100% general sanitary awareness and 37.5% to 95% awareness about microbial food hazards), excellent attitudes (97.5% to 100%), and moderate practices regarding food hygiene (17.5% to 97.5%). Although all participants had a relatively high level of awareness and attitude and participated in food safety education courses, their practices were somewhat poor.