zahra noori motlagh

The occurrence of COVID-19 as a public health emergency of international alarm was declared by the World Health Organization (WHO) on January 30, 2020. The identified transmission path is due to direct close contact or via respirational droplets. There is uncertainty about other ways, such as transmission of surfaces, air, and other sources. This study follows the preferred reporting items for systematic reviews and meta-analysis guidelines to investigate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in environmental surfaces, water, wastewater, and air.

In this study, we performed a systematic literature search in PubMed (MEDLINE), Scopus, and Web of Science (ISI) databases in August 2022. The investigation on electronic databases resulted in a total of 2049 articles. A total of 249 potentially relevant were identified for full-text evaluation. Meanwhile, 30 articles were included in the synthesis.

According to four included studies, negative detection of SARS-CoV-2 transmission in water is established. A laboratory study has shown that viable SARS-CoV-2 could be found in aerosols for about 3 h. Also, the virus can be found on dry surfaces, depending on the material of the surface, for 8 to 72 h. Our results showed it is possible to exciting SARS-CoVs in air, environmental surface, and wastewater. 

These results can help healthy policymakers make suitable assessments of main prevention measures.

The widespread presence of organic dyes in the various industries’ effluent such as paper, textile, and clothing has led to significant environmental pollution. Titanium oxide (TiO2) nanoparticles immobilized on zeolite (ZSM-5) were investigated under UV light for activation of peroxymonosulfate (PMS) for photocatalytic degradation of Orange II (OII) dye in aqueous solutions.

In this study, the photocatalyst used was prepared by immobilizing different amounts of TiO2 nanoparticles on ZSM-5. Characterization analyses including X-ray diffractometer (XRD), Fourier transform infrared (FTIR), BET, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) were performed on the synthesized samples. Then, the effect of various parameters, such as TiO2 nanoparticles loading onto the ZSM- 5, pH, contact time, dye concentration, and TiO2/ZSM-5 dosage, is investigated for the removal of OII as a model molecule under the UV irradiation with 15 W power.

The highest removal percentage of OII dye (97.44%) was obtained in the optimal operating conditions of pH = 3, the initial dye concentration = 5 ppm, amount of TiO2/ZSM-5 = 10 mg/L, amount of PMS = 50 mg/L, and reaction time = 120 minutes. The Langmuir–Hinshelwood kinetics model fitted with the experimental data.

The obtained results of this research showed that PMS can be used as a suitable oxidant activated with ZSM-5/TiO2 nanocomposite in OII degradation in different water environments, by optimizing the effective operating factors.

Nanocomposites have received remarkable attention as effective adsorbents for removal of coexisting pollutants over the last decades. The presence of heavy metals (HMs) in wastewater has caused a global health concern. Therefore, the aim of this study was to review the most relevant publications reporting the use of nanostructures to simultaneous adsorption of HMs in mixed aqueous systems.

In this systematic review, 9 studies were included through a systematic search in the three databases (ISI, Scopus, and PubMed) during 1990-2021. The optimal value of simultaneous adsorption parameters such as initial concentration, contact time, adsorbent dosage, and pH was discussed.

Findings indicate that the Langmuir and Freundlich models and the pseudo-second-order kinetic model have been widely used and the most popular models to describe the equilibrium of HMs by nanoadsorbents. This study confirmed that the simultaneous removal rate of HMs decreased with an increase in pH value. It was found that the major mechanisms of HMs adsorption onto nanostructures were electrostatic interactions and precipitation.

Nanocomposites have remarkable adsorption performance for HMs with the highest adsorption capacity (qe(mg/g)).

This study was conducted for the first time to produce activated carbon (AC) from Milkvetch wood by physical activation in order to achieve the maximum adsorbent capacity in adsorption of dye. The aim of this study was to remove acid orange 7 (AO7) dye using AC produced by physical activation with nitrogen gas.

AC activation was performed by physical method using nitrogen gas at 700°C. Scanning electron microscopy and isotherm technique were used to determine the structural characteristics of the adsorbent. The effect of operating parameters was investigated. The isotherms and kinetics of the dye adsorption were also studied.

The synthesized AC-700°C sample had a specific surface area and a total pore volume of 774 m2/g and 181.49 m3/g, respectively. The maximum adsorption of dye was 57.125 mg/g (removal efficiency 91.4%) that occurred at pH= 3, 0.04 g absorbent in 50 ml of solution, and 50 mg/l of dye in 75 min. The adsorption data followed the Langmuir adsorption isotherm model and the pseudo-second order model kinetics. Also, the ability to reuse the adsorbent using the heating method showed that the synthesized adsorbent can be used for three consecutive times with good performance. Correlation coefficients (R2) for genetic program and neural network were 0.98 and 0.99, respectively, indicating the agreement of laboratory data with the models.

The as-prepared AC by physical activation has a high potential for adsorption of AO7 dye from aqueous solutions.

The dyestuff manufacturing and textile industries consume a high volume of water and produce a great amount of wastewater containing various toxic substances. This study was conducted to evaluate the possibility of using activated carbon prepared from milk vetch wood for removing methylene blue dye from synthetic wastewater.
This research was carried out in laboratory scale with using of 100 ml volume of batch photoreactor and in chemistry laboratory of Ilam university of medical sciences (summer 2013). Activated carbon was prepared using chemical-thermal method. The effect of pH, contact time, dye concentration and adsorbent dosage on the adsorption of methylene blue dye as model organic dye was studied and kinetic and isotherm of the adsorption process was investigated. The dye concentrations were measured via spectrophotometer (665 nm wavelength).
Findings: The results showed that activated carbon prepared from milk vetch has high potential to remove dye molecules. The MB absorption capacity rates were 38.66, 40 and 48.5 mg/g respectively at pH of 3, 7 and 11 for the initial dye concentration of 50 mg/L and 0.1 g/0.1L absorbent mass at 30 minute. Also dye absorption rates were 40, 69.66, and 78.04 mg/g on absorbent respectively for 50, 100, and 150 mg/l dye concentration, at pH of 7, 1 g/0.1L absorbent mass, and 30 minutes time. Adsorption data followed Langmuir isotherm model (R2=0.99).
Discussion & Based on the obtained results, activated carbon prepared from milk vetch can be considered as an efficient adsorbent for removing dye from aqueous phase.

Cr (VI) as an extremely soluble and highly toxic ion is present in effluents of industries and imposes severe health-related problems. The current study aimed to provide information on Cr (VI) adsorption potential of fire clay as an abundant, cost-effective and untried material. Batch adsorption trials of Cr (VI) were performed to investigate the effects of pH, contact time, initial metal ion concentration and the adsorbent dosage. Langmuir, Freundlich and Dubinin–Radushkevich isotherm models were used to evaluate the equilibrium data at 20°C and regression coefficients were derived. Moreover, adsorption kinetics was analyzed using the pseudo-first-order and the pseudo-second-order kinetic models. Maximum chromium removal was found at pH 2.0. A kinetic study yielded an optimum equilibrium time of 90 minutes with an adsorbent dose of 2.5 g/50 mL. Results suggested that the equilibrium adsorption described by the Freundlich model. The kinetic data of the sorption showed that the pseudo second-order equation was the more appropriate. The results of the study indicated that fire clay was not a suitable adsorbent for Cr (IV). Apart from relatively long equilibrium time, the efficiency was not satisfactory. Therefore, searching for better alternative and/or modify such adsorbent is necessary in this area.

Actually, food sanitation is a guarantee of proper food quality and it is an essential pillar in health promoting of community. The aim of this study was to study of knowledge and attitude among Ilam University of medical sciences students regarding to food sanitation and safety on 2013. 430 Ilam University of medical sciences students was determined in present cross-sectional study by stratified random sampling. Data collected through a questionnaire consisting of three parts including personal information, knowledge and attitudes towards food sanitation and safety. The data were used by SPSS16 software and analyzed by Mann- Whitney and kruskal-wallis tests. overall, results showed that 3.5% of students had good attitude, 77.6% moderate attitude and 18.5% poor attitude. In the field of knowledge 18.5 % had adequate knowledge, 16.2% moderate knowledge and 2.4% poor knowledge about food sanitation. Results showed that there is a significant relation between student's attitudes regarding food sanitation and safety and their sex (p =. 036), and also there isaa significant relation between knowledge (p =. 000) and attitude (p =. 048) of students and passing the food sanitation course. Discussion& It is proposed that according to relation between knowledge, food sanitation and safety, educational programs to be held in the form of workshops or incorporate food sanitation courses for fields of medical science that does not pass this course.

Effluents containing synthetic dyes are hazardous to ecological systems and public health. Adsorption process is one of the treatment methods that has been attracted much attention in recent years. Therefore, the purpose of this study was to survey the feasibility of using zinc oxide (ZnO) nanoparticles stabilized on activated carbon to the methylene blue dye adsorption from synthetic wastewater. The study was conducted in the batch system. The stabilization of the nano particles on the adsorbent, in order to increase the sorption properties, was carried out by thermal procedure. The effect of various parameters including the nano particles loading, pH, contact time, dye concentration and adsorbent dose was studied on the adsorption. The reaction kinetics and adsorption isotherm was also studied. The sorption capacity of the dye by the modified activated carbon (with dye concentration= 50 mg/l, adsorbent content=0.3 g/l and contact time= 120 min) at the various loadings of nano particles (0.01, 0.1 and 0.5 g per gram of the adsorbent) was 16.6, 16.45 and 14.52 mg/g, respectively. The sorption capacity of the modified activated carbon (16.6 mg/g) was higher that of the raw sorbent (6.47 mg/g). The study showed that activated carbon modified with ZnO nanoparticles can be used as an effective method to remove Methylene blue dye in the aqueous solutions.

One of the major disadvantages of zinc oxide in aqueous solution is the light unstability of this catalyst due to the light corrosion which causes substantial reduction of photocatalytic activity of zinc oxide and application of it for environment purification. In this study, the performance of photocatalytic of UV/Silica-ZnO was compared in dye and COD removal by UV/ZnO. This study was conducted in the lab scale. The various percentages of silica nanoparticles in the combination of zinc oxides nanoparticles were fixed onto the glass by UV/Silica-ZnO process and were examined at optimum condition in the UV/ZnO process. XRD patterns of zinc oxide nanoparticles alone and accomplished by silica were conducted. X-ray diffraction, confirm that there is no impurity in nanoparticles. The different percentages of silica (5, 10 and 15%) were tested in combination with zinc oxide nanoparticles. The findings showed that the value of dye and COD removal with contact time of 90 min and 10% silica loading in UV/Silica-ZnO process were 100 % and 81%, respectively and UV/ZnO process were 66% and 44% respectively. According to the obtained results, 10% of silica, in combination with zinc oxide nanoparticles, was the best percentage. Thus, UV/Silica-ZnO process can be used as an effective method for removing dye from textile waste waters.

Effluents containing synthetic dyes are hazardous to ecological systems and public health. Methylene blue is an important chemical aromatic dye which commonly used in textile industries. Due to being aromatic، it is often toxic، carcinogenic and mutagenic. The goal of this study was to investigate the efficiency of ZnO nano particles photocatalytic process for decolorization of methylene blue by UV irradiation from synthetic textile wastewater.

In this study methylene blue photocatalytic decomposition using Ultraviolet (UV) irradiation and zinc oxide nano particles having less than 50 nm in diameter was surveyed. A batch-through Plexiglass reactor having two compartment used to conduct the experiments. Wastewater was flowed to the compartment which contains of nano ZnO stabilized glasses. UV lamps were installed at another compartment. The variables of the study included: exposure time، color concentration، light intensity، and lamp distance to the catalyst surface.

ZnO nano particles characteristics were determined by Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) analysis. Images showed that stabilizes nano particles on glass، their porosity remains in the optimal level. Optimium values for exposure time 120 minutes، color concentration 25 mg/l، light intensity 3950 μW/cm2، and distance to the catalyst surface 1 cm were achieved. At the optimal condition، methylene blue decolorization and COD removal was achieved 92. 2% and 75% respectively

Regarding the conducted experiments، the results of this studyshowed that ZnO/UV photocatalytic process has a significant efficiency in dye decolorization and COD removal. This method could be applied in the full scales.

Wastewater production is increasing every year. The variety of contaminants necessitates the application of effective and advanced treatment methods. Among the materials that are predominantly used for wastewater treatment are carbon nanotubes. Exposure to the residuals of carbon nanotubes after wastewater treatment through drinking, inhalation, and dermal contact during regular indoor activities such as bathing and cooking may pose many destructive effects on human health. Despite the potential impacts of carbon nanotubes on human health and the environment and their increased implication in recent years, the information on their toxicity in drinking water is very limited. The aim of this study was to evaluate the impacts of carbon nanotubes residuals in water on human health.