Avicenna Journal of Environmental Health Engineering
Volume:7 Issue: 2, Dec 2020

Today, due to the industrialization of societies, the existence of heavy metals has created many problems for humans, other organisms, and the environment. Lead (Pb) is highly toxic and the second most commonly used metal. The aim of this study was to evaluate the efficiency of melaminemodified nanographene oxide in the removal of Pb from aqueous media. To increase the efficiency of graphene oxide, it was mechanically converted to nano graphene oxide and melamine (4, 2 and 6-triazine, 3, 1 and 5 triamine). Experiments were performed at pH value of 3-8, temperature of 15-50°C, Pb concentration of 5-200 mg/g, adsorbent dose of 0.01-0.06 g, and contact time of 15- 150 minutes. The mechanism of the adsorption process was investigated using two Langmuir and Freundlich isotherm models, pseudo-first order and pseudo-second order kinetic equations, and thermodynamic equations. The results showed that the adsorption rate corresponds to the Freundlich isotherm model and pseudo-second order kinetic equation. Thermodynamic studies also showed that the adsorption process is associated with increasing irregularities and it is endothermic. In constant conditions (pH of 6, contact time of 60 minutes, ambient temperature of 22°C, Pb concentration of 20 mg/L, and adsorbent dose of 0.01 g), the adsorption capacity was 191.65 mg/g. The highest adsorption occurs at the concentration of 5 mg/L and the highest adsorption capacity and removal percentage was observed at a concentration of 200 mg/L, which were 1896.3 mg/g and 98.8%, respectively. Due to the high adsorption capacity, the adsorbent was able to remove lead from the contaminated environment.

Methylene blue (MB) dye is an environmental contaminant that has been mostly used in textile industry. Taguchi orthogonal array design was employed as an optimization method to reduce the number of experiments. In this research, bone char ash modified by MgO-Fe catalyst was applied for degradation of MB in catalytic ozonation process (COP) system and operational parameters including initial MB dosages, initial pH, catalyst dose, and contact time were optimized with Taguchi method. Accordingly, the best condition for the removal of MB obtained at initial MB concentration of 20 mg/L, reaction time of 15 minutes, initial pH value of 10, and catalyst concentration of 0.1 g/L. Additionally, optimization of experimental set-up showed that the MB concentration had a notable effect on MB degradation in COP process (55.6%), and reaction time had a negligible effect (1.98%). At this condition, total organic carbon (TOC) removal was determined to be 31% but in longer time, its removal increased to 65%.

Dyes are used extensively in textile industries. The wastewater of these industries contains high amounts of pollutants which can be toxic, carcinogenic, and mutagenic and needs to be treated before being discharged into the environment. The aim of this study was to evaluate the application of eggshell as a sorbent for the removal of Acid Orange 3 from synthetic wastewater. This study is applied experimental research which was performed on a laboratory scale. Eggshell as a sorbent was prepared at laboratory temperature and pulverized by standard ASTM sieves in two sizes (50 and 140). The concentration of dye in the synthetic wastewater was 25 mg/L. In this study, increasing adsorbent dose from 2 to 5 g/100 mL led to an increase in the adsorption efficiency from 36.6% to 55.36% and by decreasing the size of eggshell particles from 50 to 140 mesh, the adsorption efficiency increased. The maximum adsorption took place in the first 90 minutes of the reaction. By increasing pH from 5 to 9, the process efficiency increased from 78 to 82%; however, at pH higher than 9, the adsorption efficiency decreased. Additionally, the adsorption characteristics of this pollutant on eggshell fitted Freundlich isotherm (R2 >0.989). Due to the characteristics of textile wastewater such as alkaline pH, eggshells can be used as a natural adsorbent in textile wastewater treatment.

The trace elements (TEs) in aquatic environments due to anthropogenic activities are readily available to aquatic organisms. There are 153 fish species inhabiting the Caspian Sea. However, little is known about TE (TE) concentrations in these species. In this study, we investigated the effects of TEs levels in the brain of some bony fish species inhabiting the Caspian basin. Totally, 405 fish from nine species with different feeding behaviors including Leuciscus aspius (n = 20) and Perca fluviatilis (n = 37) as piscivores, Rutilus kutum (n = 27) and Rutilus caspius (n = 71) as carnivores, Vimba persa (n = 56), Ponticola caspia (n = 25) and Tinca tinca (n = 31) as mollusivores, and Alburnus chalcoides (n = 77) and Alosa braschnikowi (n = 61) as zooplanktivores were collected from the southwest of the Caspian Sea basin from September 2017 to June 2018. The ICP-OES was used to measure TEs in the brain tissue of fish. The variability of TEs concentrations in the brain tissues of these fishes by principal component analysis (PCA) was decreased to 63.59% and 17.68% for PC1 and PC2, respectively, exhibiting that 81.27% of the total variability is associated with K, Mg, P, S, Zn, and Al. The two-dimensional diagrams showed the weight of each component in PCA. The PC1 was mostly influenced by P, Mg, K, and Zn, while the greatest value in PC2 belonged to Al. Furthermore, the entire number of elements determined in this study was found to be a suitable indicator for the distinction between fish species based on their feeding items

One of the important aspects of drinking water pollution is the presence of heavy metals that can create hazards for consumer’s health. This study was performed to find the concentration of heavy metals (arsenic, lead, iron, and zinc) in drinking water sources of Divandarreh in Kurdistan province and prepare its zoning map. A total of 99 wells, springs, and reservoirs were selected for sampling in 78 rural areas of Divandarreh County. Samples were collected from each source using grab sampling methods in two phases (rainy and dry seasons). To find the concentration of lead, the atomic absorption device (VARIAN 240 AA) was used, and Inductively Coupled Plasma (ICP: VARIAN 710) was used for determining the concentration of arsenic, iron, and zinc. Analysis of data was done using SPSS version 22.0 and the analysis of spatial variability and estimation of the concentration of heavy metals (preparation of zoning map) in the study area were carried out by ArcGIS software. The average concentrations of arsenic, lead, iron, and zinc in dry and rainy seasons were 1, 0.6, 62.9, 31.4, and 0.13, 2.16, 11.5, 19.8, respectively. Zinc, iron, and lead concentrations in sample No. 36 were higher than the standard level; therefore, it can be inferred that these three elements can create health problems in the future.

The use of mobile phones by healthcare personnel, doctors, patients, and patients’ companions are unavoidable in health centers, especially in hospitals. Besides being rarely clean, the mobile phone is a potential reservoir of disease and pathogens and hospital infections on bedside of hospitalized patients. In this study, the microbial contamination of mobile phones and potential of transmitting infections and their antibiotic resistance pattern were investigated. In this descriptive cross-sectional study, a questionnaire was prepared to assess the importance of maternity, neonatal, and intensive care unit (ICU) staff attention to how to use and clean the cell phones in terms of valid sources. Samples were taken from 116 cell phones using a sterile swab. The standard plate count was used to detect the existing bacteria, and the antimicrobial resistance patterns of isolated bacteria were determined by standard methods. The microbial culture experiments indicated that 107 cell phones had microbial contamination, accounting for 92.24% of mobile phones. From 132 isolated strains, 115 strains (87.12%) were gram-positive while 17 were Gram-negative (12.88%). Furthermore, 67 (57.76%), 9 (7.7%), 4 (3.45%), 10 (8.62%), 12 (10.35%), 22 (19%), and 8 (6.9%) strains were coagulase-negative staphylococci, Pseudomonas aeruginosa, Staphylococcus aureus, Corynebacterium, Bacillus, Streptococcus, and Escherichia coli, respectively. The results of this study indicated that cell phones were contaminated with different types of bacteria, and that all species isolated partially played an important role in the development of hospital-acquired and opportunistic infections. Therefore, continuous disinfection of mobile phones and non-use or limited use of them in the hospitals are recommended.

In this study, the magnetic 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) – poly (4-vinylpyridine) (P4VP) was synthesized and characterized. Removal of Molybdenum (Mo) from aqueous solutions using prepared material as nanosorbent was investigated. The magnetic P4VP was prepared by copolymerization of P4VP with TMSPMA. The prepared adsorbent was characterized by various techniques including the X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The batch adsorption technique was applied and the effect of several important parameters such as pH of the aqueous solution, adsorbent dose, initial Mo(VI) concentration, contact time, and temperature was evaluated. Desorption behavior of Mo(VI) and the effect of foreign ions (Cd2+, Ca2+, Co2+, Fe3+, Ba2+ and Pt4+) in real samples were also investigated. Co (II) and Pt (IV) had a greater impact on the adsorption process than other foreign ions. The maximum capacity for Mo(VI) adsorption on the prepared adsorbent was 4.87 mg/g, which was obtained at a temperature of 40°C with an initial concentration of 10 mg/L of Mo(VI). The adsorption isotherms were best fitted with the Weber Van Vliet isotherm model. The kinetic data were fitted well with the pseudo-second-order equation with a high correlation coefficient (R2 > 0.99). Based on the negative standard Gibbs free energy change (ΔG° < 0) and the positive standard enthalpy change (ΔH° > 0), it was found that the adsorption was an endothermic and a spontaneous process in nature

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this systematic review, five databases were searched (Scopus, PubMed-/Medline, Cochrane library, Embase, and Web of Science) for publications between 2019 to 12 February 2021. From 575 articles identified, seven papers were selected for inclusion. In the present paper, corona transmission routes from three environments of water, wastewater and air were considered. The most important transmission route of COVID-19 is through the air, which takes place from the following two routes: respiration and contact. Respiratory drops are caused by coughing and sneezing. Anyone who comes in close contact with someone having COVID-19 symptoms (sneezing, coughing, etc.) is potentially at risk for droplets. In this paper, corona transmission pathways from water, wastewater, and air in three environments were investigated. The results showed that the virus is transmitted through the air and its transmission through water and wastewater has not been proven. While the virus may survive in drinking water, there is no evidence that human coronavirus is present in surface and groundwater sources, or transmitted through contaminated drinking water. There is also no evidence of SARS-CoV-2 transmission through the sewage system, with or without wastewater treatment. Detection of this virus is very effective in determining the necessary and timely strategies to prevent further transmission of virus, and help to break the chain of COVID-19 transmission through water and wastewater.