Experimental and DFT insights into nitrogen and sulfur co-doped carbon nanotubes for effective desulfurization of liquid phases: Equilibrium & kinetic study

• Synthesis of NS-CNTS is used in a high desulfurization performance. • Synthesizing NS-CNT is considered as a novel adsorbent from low-cost precursors. • A high sulfur removal capacity for NS-CNT is attained compared with recent works. Herein, nitrogen and sulfur co-doped carbon nanotubes (NS-CNT) adsorbents were synthesized via the chemical vapor deposition technique at 1000°C by employing the camphor, urea and sulfur trioxide pyridine. In this study, desulfurization of two types of mercaptans (dibenzothiophene (DBT) and tertiary butyl mercaptan (TBM) as nonlinear and linear forms of mercaptan) was studied. In this regard, a maximum capacity of NS-CNT was obtained as 106.9 and 79.4 mg/g and also the removal efficiencies of 98.6% and 88.3% were achieved after 4 h at 298K and 0.9 g of NS-CNT for DBT and TBM, respectively. Characterization of the NS-CNTs was carried out through exploiting scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and elemental analysis (CHN). The isotherm equilibrium data could be ascribed to the Freundlich nonlinear regression form and the kinetic data was fitted by nonlinear form of the pseudo second order model. The negative values of ΔS⁰, ΔH⁰ and ΔG⁰ specify that the adsorption of both types of mercaptans was a natural exothermic process with a reduced entropy. Maintenance of more than 96% of the adsorption capacity even after nine cycles suggest the NS-CNT as a superior adsorbent for mercaptans removal in the industry. Density functional theory (DFT) calculations were also performed to peruse the effects of S/N co-doping and carbon monovacancy defects in CNTs toward the adsorption of DBT and TBM.     

Hesperidin protects against aluminum-induced renal injury in rats via modulating MMP-9 and apoptosis: biochemical,histological, and ultrastructural study

Environmental Science and Pollution Research - Aluminum, one of the most abundant metallic elements, is known to be toxic to multiple organs including the kidneys. This study aimed to investigate...     

Hazardous healthcare waste management in the Kingdom of Bahrain

Hazardous healthcare waste has become an environmental concern for many developing countries including the Kingdom of Bahrain. There have been several significant obstacles facing the Kingdom in dealing with this issue including; limited documentation regarding generation, handling, management, and disposal of waste. This in turn hinders efforts to plan better healthcare waste management. In this paper, hazardous waste management status in the Kingdom has been investigated through an extensive survey carried out on selected public and private healthcare premises. Hazardous waste management practices including: waste generation, segregation, storage, collection, transportation, treatment, and disposal were determined. The results of this study along with key findings are discussed and summarized. In addition; several effective recommendations and improvements of hazardous waste management are suggested.     

Upper trapezius fatigue in carpet weaving: the impact of a repetitive task cycle

Introduction. Shoulder disorders are one of the most prevalent musculoskeletal disorders among carpet weavers. The most important cause of these disorders is muscle fatigue. The aim of the present study is to investigate the effect of carpet weaving characteristics on upper trapezius (UTr) muscle fatigue during a task cycle. Method. In this cross-sectional study, 9 women and 3 men participated. During an 80-min cycle of carpet weaving, a times-series model was applied to assess electromyography amplitude and frequency changes. Result. According to the joint analysis of electromyogram spectrum and amplitude method, the participants experienced 0% force decrease, 0.9% recovery, 18% force increase and 72% fatigue in the left UTr. Furthermore, the rates of force decrease, recovery, force increase and fatigue in the right UTr were 18%, 18%, 18% and 45%, respectively. Fatigue in the right and the left UTr was reported to be the dominant state during one carpet weaving task cycle. Conclusion. Task cycle appears to have a significant impact on UTr fatigue in participants, and UTr fatigue can be considered a serious risk factor in shoulder musculoskeletal disorders. Hence, further studies should focus on better workstations and work–rest periods during various subtasks.     

A fuzzy multi-attribute approach to select the welding process at high pressure vessel manufacturing

Metal welding process selection calls for extensive know-how which deals with a huge amount of knowledge. Hence, the automation of knowledge through a knowledge-based system will greatly enhance the decision-making process. Fuzzy analytical hierarchy process (AHP)-TOPSIS investigates the relative welding process selection factors and it can compare and evaluate different welding processes between 0 and 1.This paper describes a knowledge-base system developed for identifying the most appropriate welding processes to suit specific circumstances. In the present study, nine important welding processes were used in the system. Ten parameters namely alloy class, material thickness, deposition rate, design application, joint configuration, operator factor, capital cost, equipment portability, filler metal utilization and welding position, are used to determine the best selection among competitive welding processes for high pressure vessel production. Also the sensitivity analysis was carried out for five cases.     

Effects of microbial inoculations and surfactant levels on biologically- and chemically-assisted phytoremediation of lead-contaminated soil by maize (Zea Mays L.)

Assisted phytoremediation has been widely used for decontamination of potentially toxic elements contaminated soils. A greenhouse experiment was conducted to evaluate the effectiveness of different microbial inoculations and surfactant levels on the phytoremediation of a Pb-polluted calcareous soil by maize. The results showed that application of surfactant increased both root and shoot dry matter yields. Microbial inoculations, however, had no significant effect on the root or shoot dry matter yield. Mean Pb uptake in maize root or shoot increased only following the application of some surfactant levels. Inoculation with microorganisms significantly increased both mean Pb concentration and uptake in maize root but not in maize shoot. Application of 4?mmol surfactant kg?1 along with inoculation with Priformospora indica was effective in increasing Pb phytostabilisation potential. While the application of 2?mmol surfactant kg^?1 along with inoculation with Pseudomonas fluorescens was effective in increasing Pb phytoextraction potential. The fact that the values of translocation efficiencies were low in all treatments, demonstrated the low capability of maize for translocation of Pb from root to shoot. Inoculation with P. fluorescens was the most effective treatment in increasing metal micronutrient uptake. Microbial inoculation and surfactant levels enhanced Pb phytoremediation mostly through phytostabilisation of this metal by maize.     

Density assessment and mapping of microorganisms around a biocomposting plant in Sanandaj,Iran

Exposure to microorganisms can cause various diseases or exacerbate the excitatory responses, inflammation, dry cough and shortness of breath, reduced lung function, chronic obstructive pulmonary disease, and allergic response or allergic immune. The aim of the present study was to investigate the density of microorganisms around the air of processing facilities of a biocomposting plant. Each experiment was carried out according to ASTM E884-82 (2001) method. The samples were collected from inhaled air in four locations of the plant, which had a high traffic of workers and employees, including screen, conveyor belt, aerated compost pile, and static compost pile. The sampling was repeated five times for each location selected. The wind speed and its direction were measured using an anemometer. Temperature and humidity were also recorded at the time of sampling. The multistage impactor used for sampling was equipped with a solidified medium (agar) and a pump (with a flow rate of 28.3 l/m) for passing air through the media. It was found that the mean density of total bacteria was >1.7 × 10³ cfu/m³ in the study area. Moreover, the mean densities of fungi, intestinal bacteria (Klebsiella), and Staphylococcus aureus were 5.9 × 10³, 3.3 × 10³, and 4.1 × 10³ cfu/m³, respectively. In conclusion, according to the findings, the density of bacteria and fungi per cubic meter of air in the samples collected around the processing facilities of the biocomposting plant in Sanandaj City was higher than the microbial standard for inhaled air.     

Phytoremediation of a petroleum-polluted soil by native plant species in Lorestan Province,Iran

Petroleum hydrocarbons are potentially toxic for organisms due to the inherent properties, such as solubility, volatility, and biodegradability. The petroleum materials released from corroded old pipelines would pollute soils, shallow groundwater and air as a consequence, and threat the health of human and environment. Therefore, the removal of these compounds from environment is vital. The stability of these pollutants at the soil and their gradual accumulation over time would disrupt the normal function of the soil, such as reduced agricultural capability. In this research, the influence of two plant species (Bromus tectorum L. and Festuca arundinacea) with different amendments including arbuscular mycorrhizal fungi, alfalfa residues, and nutrient solution on the degradation rate of petroleum hydrocarbons in soil was studied. The results showed that the most effective treatment for petroleum remediation was related to B. tectorum L. plant when treated with mycorrhizal fungi and nutrient solution. The degradation rate during 40 days was about 83.27% when compared to the control. Arbuscular mycorrhizal associations are important in the restoration of degraded ecosystems because of the benefits to their symbiotic partners. This fungal phytotechnological mechanism is still in its infancy and there has been little research on aged-contaminated soils.