جستجوی مقالات مرتبط با کلیدواژه "آب آلوده" در نشریات گروه "پزشکی"

Acute viral hepatitis is one of the world's health problems today.  An outbreak of hepatitis A virus occurred in a rural area in ​​Mazandaran province, north of Iran, 2019. This research aimed at examining this outbreak in detail in order to study the epidemiological and economic burden, and the possible source of pollution.

This descriptive case report study presents the cases of seven members of a family of nine with acute symptoms of hepatitis.

In this family, seven members were found with clinical and laboratory symptoms of acute hepatitis, all of whom were positive for HAV Igm serology tests. According to the short incubation period and contamination of common origin, the most probable route of transmission, considering the health condition and residence of the people studied, was contaminated water.

According to the investigation on water plumbing system and location of the residential building (at the end of the village), contamination entered the water plumbing system through sewage and drinking water is regarded as the main cause of the disease.

With industrial development and population growth, the emerging contaminants enter into the natural water resources. Therefore, in this study Adsorption potential of NH4Cl-induced activated carbon (NAC) was investigated to remove antibiotic sulfanilamide from contaminated water.

Materials & Methods:

The effect of operational conditions including solution pH, NAC concentration, sulfanilamide initial concentration and contact time were studied.

NAC and SAC had specific surface area of 1029, 1024 and mean pore volume of 2.64, 2.23nm, respectively. With increasing the NAC concentration to 1 g/L, sulfanilamide adsorption efficiency increased to 84.4% within 40 min. Then the adsorption slightly increased with the increase in the contact time to 120 min and reached to its maximum adsorption of 99.2%. The maximum adsorption percentage of sulfanilamide onto SAC under similar conditions reached to 49.2%. The kinetics analysis showed that experimental adsorption data for both NAC and SAC were best fitted to the pseudo-second-order model. The maximum adsorption capacity of sulfanilamide onto NAC and SAC, calculated by the Langmuir model, was 238.1 and 87/7 mg/g, respectively.

Generally, these results showed that NAC was an efficient adsorbent with high removal efficiency for eliminating the antibiotics from the contaminated water streams

Anthracene is one of the chemical and persistent pollutants released into the environment and the food chain causing irreparable damage to the immune system. This study aimed at removing anthracene from aqueous solutions using modified magnetic nanoparticles.

Initially, Fe3O4 nanoparticles were synthesized with silicon dioxide shell and then modified with organic dendrimers. The adsorbent product characterized by Fourier-transform infrared, X-ray diffraction, and scanning electron microscopy. Following that, the effects of different operational parameters in the adsorption process were investigated in this study, and the UV-Vis spectrophotometer was used to measure the anthracene content in the solutions. The adsorbent resuscitation was also assessed in this study.

The highest level of removal efficiency was obtained at the reaction time of 10 min, the adsorbent dosage of 0.7 g/L, and anthracene concentration of 20 mg L−1 at pH=7. The results showed that the adsorption process followed the Langmuir isotherm and pseudo-second-order kinetics. Furthermore, the adsorbent product was capable of resuscitation up to 5 cycles.

According to the results, the synthesized magnetic dendrimer was able to remove anthracene from aqueous solutions of contaminated water with high efficiency.

Herbicides, including atrazine, are among the most important newly discovered contaminants found in water bodies and are hazardous to human health and the environment. adsorption is one of the best techniques used to remove these contaminants from  contaminated water.

In this study, two carbon from waste Pomegranate and  calligonum Comosum were used to remove atrazine herbicide. After chemical activation these carbons with NH4Cl, and then 800 ° C for 2 hours, parametric tests were performed and the effect of pH, adsorbent concentration, atrazine concentration and contact time were investigated; then absorption equilibrium tests; absorption capacity and its isotherms  investigated for the removal of atrazine by two carbons were calculated.

The results showed that the carbon produced from the calligonum Comosum wood in optimal conditions at pH =7; carbon concentration 0.2 g/L, and the mixing time of 50 minutes could remove 100% atrazine at 25 mg/L . The carbon produced from pomegranate in optimal conditions pH =6; carbon concentration of 0.2 g/L and mixing time of 50 minutes could remove 91.5% atrazine to 25 mg/ L. Absorption equilibrium tests showed that the absorption capacity of carbon Calligonum Comosum and  pomegranate were 672 and 645mg/g respectively. Discussion The results of this study showed that both carbons have high absorption capacity in the removal of atrazine herbicide and can be an effective and economical absorbent for the removal of this contaminant from natural waters.

With industrial development and population growth, the emerging contaminants enter into the natural water resources. Therefore, adsorption potential of Ammonium Chloride-induced activated carbon (NAC) to remove metolachlor pesticide from contaminated water was investigated in this study.
The effects of operational conditions including solution pH, NAC concentration, metolachlor initial concentration and contact time on the removal of metolachlor by Ammonium Chloride-induced activated carbon (NAC) and standard activated carbon (SAC) were studied.
Over 92.4% of 50 mg/L metolachlor was adsorbed using 0.3 g NAC/L within 5 min, and by increasing the reaction time to 60 min the removal efficiency reached to 100%. Under similar experimental conditions, standard activated carbon (SAC) could only adsorb 20% of metolachlor within 5 min and increase of contact time to 40 min caused the improvement of metolachlor adsorption onto SAC to 48%. The adsorption onto SAC was not influenced by the contact time over 40 min. Kinetic analysis showed that experimental adsorption data for both NAC and SAC were best fitted to the pseudo-second-order model. The maximum adsorption capacities of metolachlor onto NAC and SAC calculated by the Langmuir model were 344.8 and 238.1 mg/g, respectively.
Generally, these results showed that developed NAC was an efficient adsorbent with high removal efficiency for eliminating the halogenated pesticides from the contaminated water streams.

Presence of various microorganism, particularly human pathogens, in drinking water causes many health problems. Therefore, the water disinfection has been one of the main drinking water treatment processes. E. coli bacteria is known as an appropriate microbial water quality indicator. Electrochemical processes are very powerful for the removal of pollutants, particularly microbial contaminants, due to low environmental effects, ease of use and relative costs down for it. The aim of this study was to investigate the performance of electrochemical process in E. coli bacteria removal from water as well as the effect of various parameters on the performance of it. The electrochemical reactor was constructed and E. coli bacteria removal performance of under the influence of current density, initial bacteria population and supporting electrolyte type and concentration have evaluated. The best performance of the electrochemical system was obtained in the current density of 6 mA/cm2, concentrations of 0.25 g/l for each NaCl and Na2SO4 as supporting electrolyte and CFU/100 ml initial bacterial population. With the increasing current density up to 6 mA/cm2, efficiency of bacteria removal was significantly increased. In investigation on effect of supporting electrolyte type and concentration were shown that by increasing the concentration of NaCl, the performance showed a significant increase E. coli removal. This performance has not been obtained in the case of Na2SO4 as supporting electrolyte. With increasing of the initial bacteria number, higher time were needs to the complete elimination E.coli, when the initial bacterial number were increased.

Lack of hygiene and general health was deteriorating during Qajar era and as general hygiene was unorganized. Failure to follow personal hygiene beside lack of public education on basic health principles, caused diseases spread that some of them was due to use the polluted water. In this era use the polluted water caused many diseases such as cholera, digestive diseases, guinea worm, and skin diseases. In this study we have tried to show the impact of polluted waters on diseases spread in Naseri age from foreign tourist’s point of view. The findings show that from foreign travel writers’ point of view, lack and inadequate distribution of waters, ignorance public toward sanitation and neglect of central state to water hygiene caused water pollution in Naseri age and consequently diseases spread. The method in this cross-sectional study was conducted using information and library documents.

Common sources of chromium in wastewater are electroplating and leather industries. Thus، the present study aimed at investigating and comparing between chemical (H2O2) method and nano-photocatalytical (UV/ZnO) method in removing of Cr (VI) from polluted water. In this experimental-analytical study، effective factors on reduction process such as ZnO (0. 05–0. 15 g/L)، H2O2 (0. 5-1. 5 mol/L) for UV/H2O2 process and pH (5-9) were investigated. The initial concentration of the substrate was taken 0. 1-15mg/L. Stock chromate (V: 6) solution was prepared through dissolving Potassium dichromate (K2Cr2O7) in originally distilled water. Residual concentrations of Cr (VI) were measured spectrophotometrically at 540nm. The results indicated that with increasing reduction agent concentration and decreasing pH، the removing efficiency increased. For low initial concentrations of Cr (VI) photocatalytic process was more effective than the chemical one، but for high initial concentration the result was the opposite. In the present study، using of these procedures was applied to natural water samples. The results of this study indicated that H2O2 as a cheap and available agent and also UV/ZnO، as a friendly and without residual environmental treatment process، can be used for effective reduction of Cr (VI) to yield Cr (III).

The conventional chemical and physicalmethods for water disinfection include the application of ultraviolet (UV), chlorination, and ozonation. Water disinfection by electrochemical methods has been increasingly carried out recently. The goal of this applied. analytical research is to investigate the removal of E. coli bacteria, as the index of water microbial contamination, from drinking water by electrochemistry method. In this study, the contaminated water sample was prepared through adding 102 and 103 E. coli bacteria per ml of drinking water. The contaminated water entered into the electrochemical reactor and different conditions were studied, included pH (6, 7, and 8), number of bacterium (102 and 103 per milliliter), time (5, 10, 20, and 40 min), distance between electrodes (2,2.5, 3, and 3.5 cm), and voltage (10, 20, 30, and 40 volts). The findings indicated the indirect correlation between bacteria removal efficiency and the variable distances between two electrode. The results indicated the direct correlation between bacteria removal efficiency and the variables voltage and electrolysis times. The results showed that the best conditions for removal of 102 and 103 bacteria per milliliter obtained at pH 7, electrolysis time of 10 min, distance between electrodes 2 cm, in the voltage 20 and 30 volts, respectively. The results of this study indicate that voltage and electrolysis time have the most significant effect on electrolysis efficiency. Research findings showed that electrolysis is a promising method for removal of E. coli bacterium from drinking water.