Papers by Yalda Hashempour
DOAJ (DOAJ: Directory of Open Access Journals), Jul 1, 2015
The presence of humic acid (HA) in water treatment processes is very harmful and the cause of und... more The presence of humic acid (HA) in water treatment processes is very harmful and the cause of undesirable color, taste, and smell. Drinking water containing high concentrations of humic substances can be the cause of many health problems. Therefore, the removal of these compounds from water resources is a very important topic. In this research, response surface methodology (RSM) has been used to optimize the effect of main operational variables responsible for higher HA removal by activated carbon (AC). A three-level Box-Behnken factorial design (BBD) was used to optimize initial concentration of HA, time, pH, and AC dose for humic substances removal. The characterization of AC was carried out using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) analysis. A coefficient of determination (R 2) value of 0.98, model Fvalue of 82.32 and its low P (F < 0.0001), and low value of coefficient of variation (9.94%) indicated the fitness of the response surface quadratic model during the present study. At initial optimum concentration (5.25 mg HA/l), pH (5.85), contact time (36.01 minutes), and dose (1.38 g AC/L), the model predicted 1.90 mg HA/l. Equilibrium adsorption of HA onto AC had best fitness with the Freundlich isotherm and pseudo-second-order kinetic model.
Introduction: considering the increase in the use of Chlorine-based disinfectants and the questio... more Introduction: considering the increase in the use of Chlorine-based disinfectants and the questions about the shelf-life of chlorine in solutions, its persistence on the surface, etc., the present study investigated the effect of environmental factors on the stability of commercial solutions stored in different conditions.Materials and methods Three brands of commercial Chlorine-based sanitizers (Golrang, Active, and Tage) were tested. Stability of 0.05, 0.5, and 1% solutions with the pH of 5, 7.5, and 10 stored at 4°C, 25°C, and 45°C were assessed using iodometric titration in 0, 15, 30, and 60 days after preparation. 87 solutions were prepared based on Experimental Design and Response Surface Modeling (RSM) the utilization of Box-Behnken factorial design (BBD).Results Based on RSM and BBD, the effects of linear coefficients of all factors were significant (p < 0.05) and there were no statistically significant differences among the three brands (p = 0.307). There was a negative ...
Journal of Mazandaran University of Medical Sciences, Dec 10, 2020
Journal of Health Research, Jan 10, 2021
Journal of Water Chemistry and Technology, 2013
This study describes the acute toxicity of sodium cyanide on the crustacean Daphnia magna (Cladoc... more This study describes the acute toxicity of sodium cyanide on the crustacean Daphnia magna (Cladocera). A new flow-through system was innovated in which the microorganism continuously exposure to the toxicity of sodium cyanide during the test. We used twelve different concentration of sodium cyanide from low values (0 mg CN/L) to high values (1 mg CN/L) on bioassay test. D. magna were exposed to the concentrations for 24, 48, 72 and 96 h at 20–25°C. We controlled the three important parameters such as temperature, pH and DO to meet the standard requirements. The LC50 values for 24, 48, 72 and 96 h (95% confidence limits in parentheses) were estimated statistically by the probit methods and were 0.171 (0.163–0.179), 0.12 (0.112–0.128), 0.07 (0.062–0.078) and 0.019 (0.011–0.027) mg/L respectively. Finally, we proposed two new values for SAR (safe application rate) and SAFE Coefficients.
Journal of Mazandaran University of Medical Sciences, 2021
Background and purpose: The world has made unprecedented efforts to control the Coronavirus disea... more Background and purpose: The world has made unprecedented efforts to control the Coronavirus disease 2019 (COVID-19), however, the number of positive cases are increasingly being seen every day Therefore, there is an urgent need for more effective preventive measures to limit the spread of the infection which require more precise understanding of the routes of transmission and its stability in different environments Materials and methods: In this review, all articles published up to September, 2020 on the stability of coronaviruses, including SARS-CoV-2 were studied PubMed, Scopus, Web of Science, Sciencedirect and Google Scholar were thoroughly searched Keywords used in the search were Coronavirus, SARS-CoV-2, COVID-19, and Stability The World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) updates were also used for the latest information on the disease Results: Transmission of SARS-CoV-2 was observed to be through aerosols SARS-CoV-2 and other hu...
Journal of Mazandaran University of Medical Sciences, 2021
Civil Engineering Journal, 2018
Carbon aerogel its fabrication and characterization and its uses in this process were studied for... more Carbon aerogel its fabrication and characterization and its uses in this process were studied for desalinating of saline and brackish water. The carbon aerogel manufacturing process involves the polymerization and pyrolysis of the mixture of resorcinol and formaldehyde. Carbon aerogels were analyzed using BET, BJH, and T-plot after construction. The effect of various parameters (including the influent salt concentration, the intensity of electric current flow, the distance between the electrodes and pH) on salt adsorption were studied. Analysis of BET/BJH shown that the surface of aerogel was 677.8 m2/g. much of porosity in the samples of carbon aerogel were between 1-2 nm, namely micro-pour and a similar level 0f 456 m2/gr is dedicated to micro-pour, with a correlation coefficient (r) equal to 94.5. According to the results, it seems that carbon aerogel electrodes have a good structure in desalination of brackish and saline water.
Civil Engineering Journal, 2017
Multi-pollutant air pollution dramatically occurs in wide range of regions across Tehran. Air qua... more Multi-pollutant air pollution dramatically occurs in wide range of regions across Tehran. Air quality index (AQI) is applied worldwide to inform the public about levels of air pollution and related to health risks. Assessing air pollution, and transferring information about its possible adverse health effects, may encourage population and policy makers to reduce activities that increase pollution levels. In this study the Air quality index (AQI), Aggregate Air quality index (AAQI), and a relative index of variability (VR) were obtained for the data in order to better investigate air pollution conditions for the whole areas of a city of Tehran, aim at warning the people of short-term health impact. The proposed index of variability does add precious information to the aggregate AQI, as it can demonstrate whether the value assumed by the AQI is influenced by one or more pollutants. The two indices are together used on simulated data and consider different possible scenarios. In addition, Applications to real air pollution data are reported. Before applying the two indices, the effects of different standardizations on data are evaluated from a theoretical point of view.
Environmental Engineering and Management Journal, 2016
High contents of colloidal and organic materials in municipal wastewater sludge cause problems in... more High contents of colloidal and organic materials in municipal wastewater sludge cause problems in the process of dewatering. The filtering efficiency can be improved by chemical conditioning, but the effectiveness of mechanical dewatering is limited because flocculated sludge is highly compressible. Physical conditioners such as bagasse can be used to facilitate mechanical dewatering. This paper describes the use of bagasse pith (cane sugar waste fiber) to improve the dewatering process of municipal wastewater sludge. The effectiveness of the process was examined using a lab scale filter press. Experiments to evaluate the influence of pith showed that conditioning of sludge with pith entailed better dewatering than that of flocculated sludge alone. Conditioning with pith yields a more porous, rigid and permeable structure that allows the water to pass through it more easily. In addition, bagasse pith has a relatively high cellulose content that effects the C:N ratio; changing it to an average of 35 when dewatered sludge is composted.
Waste Management & Research, 2009
Direct application of aerobic biodegradation for leachate treatment is not feasible due to high c... more Direct application of aerobic biodegradation for leachate treatment is not feasible due to high concentrations of nitrogen and chemical oxygen demand. Several potential leachate treatment schemes incorporating struvite precipitation as pretreatment and two types of activated sludge processes (conventional activated sludge and batch decant reactor (intermittent cycle extended aeration system [ICEAS process]) with and without addition of powdered activated carbon (PAC) were evaluated in this study. The hydraulic retention times (HRT) of 6 h and 12 h were applied in the biological stages of each process. Treatment schemes incorporating PAC addition showed acceptable results. In the conventional activated sludge process, total chemical oxygen demand (TCOD), soluble chemical oxygen demand (SCOD), NH3, and P removal rates were 87, 84, 98.3, and 94%, respectively, with HRT of 6 h and 95.8, 95.1, 99.1, and 98.7% with HRT of 12 h. For the ICEAS process, removal rates were 89.3, 87.9, 98.2, a...
Science of The Total Environment
Environmental Health Engineering and Management
Background: Malachite green (MG) is widely used as a fungicide, Bactericide parasiticide in the a... more Background: Malachite green (MG) is widely used as a fungicide, Bactericide parasiticide in the aquaculture industry, as a food additive, medical disinfectant, and also, as a dye for materials such as silk, leather, paper, etc. In this study, the photocatalytic removal of MG from aqueous solutions using TiO2-containing nanocomposites was reviewed. Methods: In this study, four databases (PubMed, Web of Science, ScienceDirect, and Scopus) were systematically searched to collect studies on the decomposition of MG using nanocomposites containing TiO2 under UV light radiation. Results: In total, 10 related and eligible studies were selected. Based on the results, TiO2 was doped with iron, Sn, Ag, Si, and Ni. The highest percentage of photocatalytic decomposition for MG was observed in Sn > Ni > Ag > Fe > Si. The removal efficiency of MG in the studied papers was between 75%-100%. Conclusion: Recombinant nanocomposites had a higher dye removal percentage than uncombined ones b...
Journal of Advances in Environmental Health Research, 2015
The presence of humic acid (HA) in water treatment processes is very harmful and the cause of und... more The presence of humic acid (HA) in water treatment processes is very harmful and the cause of undesirable color, taste, and smell. Drinking water containing high concentrations of humic substances can be the cause of many health problems. Therefore, the removal of these compounds from water resources is a very important topic. In this research, response surface methodology (RSM) has been used to optimize the effect of main operational variables responsible for higher HA removal by activated carbon (AC). A three-level Box–Behnken factorial design (BBD) was used to optimize initial concentration of HA, time, pH, and AC dose for humic substances removal. The characterization of AC was carried out using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) analysis. A coefficient of determination (R 2 ) value of 0.98, model F-value of 82.32 and its low P-value (F < 0.0001), and low value of coefficient of variation (9.94%) indicat...
Introduction: Formaldehyde is used in many industrial applications as raw material and therefore ... more Introduction: Formaldehyde is used in many industrial applications as raw material and therefore high concentrations are found in their effluents. Activated sludge processes based on biofilm growth are increasingly used because of appreciate abilities in controlling of high organic load industrial effluents. The main objective of this study was to determine the effect of biofilm in improvement of activated sludge efficiency for treatment of industrial effluents containing formaldehyde. Materials and Methods: Two lab scale activated sludge reactors (with and without fixed bed for biofilm growth) were investigated in organic loading rate of 0.7-10.5 kgCOD/m3.d, aerobic condition and the room temperature. In this study, the effects of organic and hydraulic loads were investigated for the mentioned two processes. Results: The most COD removal efficiency for biofilm activated sludge was 98.86. The reactor containing biofilm had removal efficiency of more than 64 up to the organic loading...
International Journal of Environmental Analytical Chemistry
As a result of urbanisation and increased anthropogenic activity, heavy metal pollution in soil, ... more As a result of urbanisation and increased anthropogenic activity, heavy metal pollution in soil, water, and the mesosphere indicates the growth of environmental problems affecting food quality and human health in cities. The present study aimed to systematically review Cadmium (Cd) and Lead (Pb) concentrations in polluted soil that used phytoremediation for cleaning. International databases were searched from January 2005 to February 2020. Data obtained from 11 articles showed that minimum and maximum concentrations of Cd (0.032 ± 0.027 and 22.84 ± 2.59 mg/kg respectively) and Pb (0.05 ± 0.15 and 15.40 ± 10.05 mg/kg), respectively. The concentration of heavy metals was more in Guangzhou, China. The minimum and maximum concentrations of heavy metals were for Cd in Bingham, England, and Guangzhou, China respectively. Soil pH affects the ability to extract cadmium in the soil and by increasing soil pH, increases the uptake of cadmium or decreases the dissolution of cadmium-containing minerals. The use of residues including a variety of biochar to help contaminated soils can be an effective and sustainable way to purify lead-contaminated soils and increase food safety and health.
Environmental Science and Pollution Research
Cosmetics can contain harmful compounds such as heavy metals. Several metals have a cumulative ef... more Cosmetics can contain harmful compounds such as heavy metals. Several metals have a cumulative effect on the body, especially fatty tissues, and may have different health effects on the human body over the long term. Therefore, the main objective of this study was to assess the health risks of heavy metals in cosmetics in Iran. Also, in this study, Monte Carlo simulation was used to investigate uncertainties. In this study, heavy metals data of cosmetics were extracted from studies carried out at intervals 2010–2018. International and Iranian databases such as Google Scholar, Web of Science, Springer, Science Direct, PubMed, Scopus, Irandoc, Magiran, Scientific Information Database (SID), and Information Institute for Scientific (ISC) were searched for this purpose. In this study, the index of the Margin of Safety was calculated to determine the risk of human contact with metallic impurities in cosmetic products used by humans. In the selected period, 11 studies were conducted on the measurement of heavy metals in cosmetics in Iran. In these studies, cosmetics such as eye shadow, eye pencil, powder, cream, and lipstick were studied. The Margin of Safety (MoS) values calculated for different metals were higher than the established safe standard by WHO. The highest and lowest amount of systemic exposure dosage in all types of cosmetic investigated (lipstick, cream, eye pencil, face powder, and eye shadow) was related to Fe and Hg. The mean hazardous quotient (HQ) for Cd, Cr, Ni, Cu, Mn, Zn, Pb, and Hg was 1.05E-03, 1.03E-01, 7.95E-03, 2.59E-03, 1.05E-03, 4.98E-03, 7.22E-04, 1.85E-01, and 1.35E-05, respectively. The highest HQ (6.10E-01) was found for Pb, which was observed in the cream.
Sustainable Cities and Society
Abstract Evaluation of the impact of climate change on water sectors is one of the most important... more Abstract Evaluation of the impact of climate change on water sectors is one of the most important challenges of water resources management in the current century. In this paper, assessment of vulnerability to climate change on total organic carbon (TOC) concentration in the Jajrood catchment in Tehran has been done. The hydroclimatologic parts of the assessment have been done by implementing HYMOD and downscaling of precipitation, temperature and evaporation using statistical downscaling model (SDSM). Three climate change scenarios (RCP 2.6, RCP 4.5 and RCP 8.5) from the Canadian Earth System Model have been used to project climate change (2006 to 2050). Moreover, different linear models were used to model water quality in Latyan Dam and Tehranpars Water Treatment Plant (TWTP). Based on the results, the average annual simulated rainfall under RCP 2.6, RCP 4.5, and RCP 8.5 are 670.2, 658.06 and 650.93 mm, respectively. The projected streamflow under the scenarios were 97%, 90%, and 92%, respectively, more than observation period. The average simulated TOC concentration in influent water was 52.43 (mg/L), which was about seven times more than the averaged observed value (8.78 mg/L). The most important byproduct of the current impact assessment is to define an adaptation action plan, because the TWTP will not be able to provide drinking water standards in this area.
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Papers by Yalda Hashempour