Publications by authors named "Amir Hossein Mahvi"

164 Publications

Process modeling, characterization, optimization, and mechanisms of fluoride adsorption using magnetic agro-based adsorbent.

J Environ Manage 2021 Feb 19;286:112173. Epub 2021 Feb 19.

Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

In this study, fluoride removal from polluted potable water using magnetic carbon-based adsorbents derived from agricultural biomass was thoroughly investigated. An experimental matrix is designed considering the interactive effects of independent process variables (pH, adsorbent dose, contact time, and initial fluoride concentration) on the removal efficiency. Isotherms and kinetics studies, as well as anions interactions, were also investigated to understand the adsorption mechanisms further. The model parameters of isotherms and kinetics are estimated using nonlinear differential evolution optimization (DEO). Approaches like adaptive neuro-fuzzy inference system (ANFIS) and response surface methodology (RSM) are implemented to predict the fluoride removal and identify the optimal process values. The optimum removal efficiency of GAC-FeO (89.34%) was found to be higher than that of PAC-FeO (85.14%). Kinetics experiments indicated that they follow the intraparticle diffusion model, and adsorption isotherms indicated that they follow Langmuir and Freundlich models. Both PAC-FeO and GAC-FeO adsorbents have shown an adsorption capacity of 1.20 and 2.74 mg/g, respectively. The model predictions from ANFIS have a strong correlation with experimental results and superior to RSM predictions. The shape of the contours depicts the nonlinearity of the interactive effects and the mechanisms in the adsorption process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jenvman.2021.112173DOI Listing
February 2021

Municipal solid waste recycling: Impacts on energy savings and air pollution.

J Air Waste Manag Assoc 2021 Mar 2:1-17. Epub 2021 Mar 2.

University of Mazandaran, Babolsar, Iran.

In recent years, recycling of municipal solid waste (MSW) has been recognized as one of the most efficient methods of waste management in terms of environmental benefits. This study investigates the energy savings and other environmental benefits of recycling of dry MSW collected in Shiraz, Iran (2018). The impact of different recycling rates (current = 15%, desirable = 50%, ideal = 80%) on environmental benefits and energy savings were assessed. The annual quantity of recycled components were defined as glass (735 tons), plastic carrier bags (555 tons), cardboard (3,874 tons), paper (3,806 tons), disposable plastic containers (287 tons), other types of metals (785 tons), disposable metallic containers (aluminum) (171 tons), other types of plastics (812 tons) and polyethylene terephthalate (PET) (887 tons). The results confirmed that recycling of paper and glass in three different scenarios resulted in a reduction of 1.01, 2.14, and 3.43 million tons of air pollutant emissions, respectively. By improving the recycling rates from 15 to 80%, overall energy savings can improve by between a factor of 3.5 to 5.5. Also, a reduction of approximately 2-3.5% in air pollutant emissions can be achieved by upgrading the current recycling program (15% recycling rate) to favorable and ideal conditions.: In recent years, recycling of municipal solid waste (MSW) has been recognized as one of the most efficient methods of waste management in terms of environmental benefits. This study investigates the energy savings and other environmental benefits of recycling of dry MSW collected in Shiraz, Iran (2018). According to available data, there has been little effort for recycling in developing countries, and waste landfilling is recognized as the most favorable option in MSW management. The aim of this study was to characterize MSW components in Shiraz, Iran, and to quantify the environmental benefits and energy savings as result of paper, glass, and aluminum recycling. This work is novel in that there are no reports to our knowledge of the environmental benefits and energy savings resulting from different recycling scenarios including current (15%), desirable (50%), and ideal (80%) recycling for aluminum, paper, and glass. The results of this work have broad implications both for other regions owing to the pervasiveness of recycling facilities and also for developing countries that can strive towards the infrastructure needed to reach improved recycling scenarios.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/10962247.2021.1883770DOI Listing
March 2021

A comprehensive systematic review of photocatalytic degradation of pesticides using nano TiO.

Environ Sci Pollut Res Int 2021 Jan 23. Epub 2021 Jan 23.

Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

This study has systematically reviewed all of the research articles about the photocatalytic degradation of pesticides using titanium dioxide (TiO) nanoparticles (NPs) and ultraviolet (UV) irradiation. Online databases were searched for peer-reviewed research articles and conference proceedings published during 2009-2019, and ultimately 112 eligible articles were included in the review. Fifty-three active ingredients of pesticides and one mixture had been investigated, most of them were organophosphorus (22%), followed by triazine derivatives (11%), chloropyridines (9%), and organochlorines (9%). Sixteen types of TiO with an average photodegradation efficiency of 71% were determined. Based on the type of pesticide and experimental conditions such as irradiation time, the complete photodegradation had been observed. The removal of each group of pesticides has been sufficiently discussed in the article. Effect of experimental conditions on photocatalytic activity has been investigated using linear and polynomial regressions. The strategies to reduce the required energy for this process, doping TiO with metal and non-metal agents, innovative reactor designs, etc., were also discussed. In conclusion, TiO NPs have been successful for degradation of pesticides. Future direction for research incorporates developing and application of heterogeneous doped and immobilized titania having optimized characteristics such as surface area, reactive centers, recombination rate, and phase, and capable to photo-degrade low levels of pesticides residues under solar light in an efficient full-scale size.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-021-12576-8DOI Listing
January 2021

Monitoring of caffeine concentration in infused tea, human urine, domestic wastewater and different water resources in southeast of Iran- caffeine an alternative indicator for contamination of human origin.

J Environ Manage 2021 Apr 19;283:111971. Epub 2021 Jan 19.

Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran; Center for Solid Waste Research (CSWR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

The present study was developed to evaluate the caffeine concentration in commercially high-consumed brands of dry black tea, urine of tea consumers, raw and treated wastewater, as well as water resources (WRs) in Zabol city, Iran. Furthermore, a complementary analysis was performed to evaluate the relationship between caffeine content and total coliform (TCF) and Escherichia coli (E. coli) in water sources. In this end, tea (90 samples), urine (90 samples), raw sewage (72 samples), treated sewage (72 samples), and septic tank sewage (36samples) were taken from Zabol city and analyzed in terms of caffeine content. To evaluate the correlation between caffeine and TCF and E. coli, 102 water samples were taken from WRs in Zabol city. Caffeine was measured by high-performance liquid chromatography (HPLC). Furthermore, TFC and E. coli were measured based on the procedure outlined by standard methods for water and wastewater examination and the most probable number (MPN) method. The results indicated that the caffeine concentration in different tea brands consumed by Zabol people were in the range of 12.35-18.75 mg/L. The mean caffeine level in the male group' urine (7.08 ± 1.00 μg/mL) was significantly higher than the female group (4.83 ± 1.94 μg/mL). The results showed that the total average amount of caffeine in raw and treated wastewater in Zabol city was 21.04 ± 2.22 and 19.86 ± 2.08 μg/L, respectively. Besides, the caffeine removal efficiency by the Zabol wastewater treatment plant (ZWTP) was found to be between 4.79 and 51.39%. According to the results, the environmental risk associated with caffeine through the discharge of raw and treated wastewater from ZWTP into receiving WRs was estimated to be less than the allowable limit (RQ = 1). The results showed that caffeine could be an indicator for fecal contamination with human origin.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jenvman.2021.111971DOI Listing
April 2021

Determination of bacterial and fungal bioaerosols in municipal solid-waste processing facilities of Tehran.

J Environ Health Sci Eng 2020 Dec 6;18(2):865-872. Epub 2020 Jul 6.

School of Public Health, Shiraz University of Medical Sciences, Shiraz, Iran.

Purpose: The concentration and distribution characteristics of airborne bacteria and fungi were assessed at municipal solid-waste processing and disposal facilities (SWPDFs) of Tehran (Arad Kouh Site).

Methods: Air samples were obtained from the indoor air of a laboratory and refectory as well as from the air surrounding a conveyor belt, rotary screen, and bailer. Sampling was conducted according to the standard procedure to determine two bacterial species ( and ), total bacteria and fungi, and .

Results: The maximum concentration of was in the air surrounding the conveyer belt with the average of 993.2 CFU/m. The highest concentrations of total fungi (4958.8 CFU/m) and (2114 CFU/m) were measured in the air surrounding the rotary screen. The mean concentrations of bacterial bioaerosols in a more contaminated sampling location in summer and winter were 1687.6 and 1479.4 CFU/m, respectively.

Conclusions: There were significant differences between the concentration of bioaerosols in cold and warm seasons. The concentrations of bioaerosols in the air surrounding the rotary screen and conveyer belt were significantly more than those in other sampling locations, but were within the recommended maximum of 10 and 10 CFU/m.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40201-020-00510-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7721842PMC
December 2020

Dielectric barrier discharge plasma with photocatalysts as a hybrid emerging technology for degradation of synthetic organic compounds in aqueous environments: A critical review.

Chemosphere 2021 Jan 23;263:128065. Epub 2020 Aug 23.

Research Center of Prevention and Epidemiology of Non-Communicable Disease, Department of Biostatistics and Epidemiology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.

Dielectric barrier discharge (DBD) plasma has been recently used for removal of synthetic organic compounds (SOCs) from aqueous environments. The removal of SOCs by alone DBD is significantly limited by its high electricity needs and inefficient mineralization, which affects the further application of DBD for SOCs. The combined application of DBD with other technologies and the addition of a supplementary substance for energy-saving were proposed to resolve these problems. The addition of catalysts is considered to be a promising and innovative approach to increase the energy yield of DBD, improve the environment friendly of DBD, develop the variety of goal SOCs, and improve the removal efficiency of DBD system. Despite the increasing use of the coupling form of DBD and catalysts, as catalytic dielectric barrier discharge (CDBD), but it still requires a comprehensive review to summarize the last studies and highlight the future perspectives in this area. Therefore, this work is the first literature review aimed to critically assess the latest developments of catalysts coupling with DBD employed in aqueous environments. Moreover, performance evaluation, energy yield, toxicity, eco-friendly, and future perspectives of the CDBD systems for SOCs removal were discussed and overviewed. The results showed that the coupling of catalysts with DBD presents synergistic effects and had excellent removal performance for aqueous SOCs. Overall, it can be concluded that the essential principles of environmental and economic sustainability have been addressed for the removal of persistent pollutants from aqueous environments in the CDBD systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2020.128065DOI Listing
January 2021

Gamma radiation in the mineral hot springs of Ardabil, Iran: Assessment of Environmental Dose Rate and health risk for swimmers.

Environ Monit Assess 2020 Jun 15;192(7):431. Epub 2020 Jun 15.

Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

The main aim of this study was to evaluate gamma radiation level in the mineral hot springs of Ardabil province in Iran. In addition, the cancer risk of gamma radiation was assessed for swimmers. Natural gamma radiation was measured using Ion Chamber Survey Meter 451B in 22 springs throughout the province. Gamma was measured at 20 cm and 100 cm above the ground level in 15 locations of each spring. Excess lifetime cancer risk was calculated to investigate the risk of exposure to gamma radiation. The highest and lowest annual absorbed dose rate of gamma were found to be 1.17(10) and 1.99(10) Sv/y at the height of 20 cm above the ground level and 5.26(10) and 1.52(10) Sv/y at the height of 100 cm above the ground level, respectively. Excess lifetime cancer risk ranged from 4.57(10) to 7.76(10) at the height of 20 cm and from 2.06(10) to 5.94(10) at the height of 100 cm which are lower than global average of 1.45(10) declared by the United Nations. Although the risk level in this study is lower than the global average, protective and preventive measures should be considered by individuals and authorities in these areas to reduce the effects of gamma radiation on the health of the swimmers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10661-020-08402-2DOI Listing
June 2020

Comprehensive Risk Assessment of Health-Related Hazardous Events in the Drinking Water Supply System from Source to Tap in Gaza Strip, Palestine.

J Environ Public Health 2020 29;2020:7194780. Epub 2020 Jan 29.

Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.

Background: The traditional approach in the management of the quality drinking water, and relying on end-product testing, has proven ineffective in protecting public health. Therefore, the transition to a systematic approach in drinking water supply systems management from the source to the consumer tap was taken as a water safety plan (WSP).

Objective: The study aims to investigate the health-related hazardous events in order to decide on the best risk-reduction strategies in the supply of drinking water in the Gaza strip.

Methods: A semiquantitative matrix method for risk assessment was applied. Also, chlorine residual, electrical conductivity, and nitrate concentration further tested in 109 water wells, 109 small-scale water desalination plants, 197 tanker trucks, and 384 households distributed over five governorates of the Gaza strip.

Results: The mean of the measured chlorine residual values was less than the recommended national and international limits (0.2-1 mg/liter). The mean of electrical conductivity at catchment points and household municipal water taps was 2165.1 S·cm and 2000 S·cm, respectively. Furthermore, zero percent of water samples met the recommended criteria, indicating that the groundwater in the Gaza strip is nonpotable. Only 12.8% and 8.8% of water samples met the permissible levels at catchment areas and municipal water at household, respectively, indicating sever health impacts on the public. Moreover, the most hazardous events were related to high levels of groundwater salinity, the low level of disinfection, the effect of electricity outages on the efficiency of the desalination process, and leakage of water from the tanker truck tank reservoirs. Therefore, urgent interventions are required to improve the quality of water and to mitigate the possible health effects.

Conclusion: The prioritization of hazardous events that are proportional to the degree of their attributed risk could help guide in making the right risk-reduction decisions. Urgent interventions are required to improve the quality of water and to mitigate the possible health effects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/7194780DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204139PMC
September 2020

Bio-efficacy of ultrasound exposure against immature stages of common house mosquitoes under laboratory conditions.

Int J Radiat Biol 2020 07 10;96(7):937-942. Epub 2020 Apr 10.

Center for Communicable Diseases Control, Ministry of Health and Medical Education, Malaria Control Unit, Tehran, Iran.

In southern Iran with a tropical climate, the above and underground cisterns of drinking water are the main habitats for immature stages of mosquitoes. The local people do not agree with using calcium hypochlorite granules in the water cisterns due to the change of water taste. Following the increased worldwide interest in using ultrasound technology for water disinfection, this study was conducted to assess the possible dual effects of ultrasound waves against immature mosquitoes. Combinations of four power levels, two frequencies, three temperatures, and eight exposure times were applied to immature . The exposure chamber of immature mosquitoes was the disposable cups placed inside a sonication bath containing tap water. The mortality rate of immature mosquitos was 85-91% at 10-25 W, 30 °C and 130 kHz. The most effective ultrasound regimen for causing immature mortality included a fixed frequency of 130 kHz, a temperature of 30 °C, and a power level of 20-25 W. The lowest efficacy was observed in the egg stage. The median lethal time (LT) and ninety percent lethal time (LT) of sonication was 5.9 ± 0.6 min and 1.6 ± 0.1 min at 30 °C and a fixed frequency of 130 kHz. Evidence indicated effective ultrasound irradiation against immature mosquitoes in the water. This study provides a clear scientific basis for larvicidal properties induced by ultrasound emissions at laboratory conditions. The findings could be used for setting the ultrasound devices in the field investigations for achieving desired effectiveness.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/09553002.2020.1748909DOI Listing
July 2020

Comprehensive systematic review and meta-analysis of dyes adsorption by carbon-based adsorbent materials: Classification and analysis of last decade studies.

Chemosphere 2020 Jul 17;250:126238. Epub 2020 Feb 17.

Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Carbon-based materials and their modifications have received significant attention over the last decades given the outstanding adsorption behavior toward various dyes from aqueous solutions. In this systematic review and meta-analysis, the adsorption capability of dyes on carbon-based adsorbent materials (CBAMs) has been compiled. Further, the effects of process variables i.e., pH, adsorbent dosage, contact time, and initial concentration), adsorption kinetics, and isotherms were investigated while considering the classification of different groups of dyes and adsorbents. The Metafor package provides functions for conducting meta-analyses in R software. Electronic databases, including PubMed, Web of Science, and Scopus were systematically searched based on Medical Subject Headings (MeSH) from January 1, 2009 to May 1, 2018. The following parameters were evaluated according to predetermined inclusion and exclusion criteria. After detailed screening and analysis, 835 articles were eligible for the review section. Among them, 87 studies met all quantitative criteria for the meta-analysis. The meta-analysis was performed using a random-effects model with a high heterogeneity (I = 99.99%). According to the evidence, basic dyes with n = 661 (∼50%) and powder activated carbon (PAC) sorbent with n = 752 (∼57%) have received the most attention among researchers. The results revealed that the mean of removal efficiency-based dyes classification was between 79.9 and 93.7% and the adsorption capacity was lied within the range of 76.8-303.6 mg/g. Meanwhile, the maximum adsorption capacity belongs to graphene families with Qm > 320 mg/g, while the minimum Qm was related to G and GAC with capacities of 108.5 and 110.7 mg/g, respectively. Pseudo-second-order kinetic model with 88.7% and Langmuir isotherm with 74% had the best fitting with the data studied. Baujat plot revealed that two studies (ID: 75 and 12) had the minimum influence on adsorption capacity with the highest dffits and cook's distance. According to the pooled data, the mean adsorption capacity varied between 140.90 and 208.25, with a mean of 174.57 mg/g across all studies. The results of Egger's test (t = 0.1332, p = 0.0844) and Begg's test (z = 0.8458, p = 0.3977) were not statistically significant, suggesting that no potential publication bias existed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2020.126238DOI Listing
July 2020

Comprehensive systematic review and meta-analysis of dyes adsorption by carbon-based adsorbent materials: Classification and analysis of last decade studies.

Chemosphere 2020 Jul 17;250:126238. Epub 2020 Feb 17.

Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Carbon-based materials and their modifications have received significant attention over the last decades given the outstanding adsorption behavior toward various dyes from aqueous solutions. In this systematic review and meta-analysis, the adsorption capability of dyes on carbon-based adsorbent materials (CBAMs) has been compiled. Further, the effects of process variables i.e., pH, adsorbent dosage, contact time, and initial concentration), adsorption kinetics, and isotherms were investigated while considering the classification of different groups of dyes and adsorbents. The Metafor package provides functions for conducting meta-analyses in R software. Electronic databases, including PubMed, Web of Science, and Scopus were systematically searched based on Medical Subject Headings (MeSH) from January 1, 2009 to May 1, 2018. The following parameters were evaluated according to predetermined inclusion and exclusion criteria. After detailed screening and analysis, 835 articles were eligible for the review section. Among them, 87 studies met all quantitative criteria for the meta-analysis. The meta-analysis was performed using a random-effects model with a high heterogeneity (I = 99.99%). According to the evidence, basic dyes with n = 661 (∼50%) and powder activated carbon (PAC) sorbent with n = 752 (∼57%) have received the most attention among researchers. The results revealed that the mean of removal efficiency-based dyes classification was between 79.9 and 93.7% and the adsorption capacity was lied within the range of 76.8-303.6 mg/g. Meanwhile, the maximum adsorption capacity belongs to graphene families with Qm > 320 mg/g, while the minimum Qm was related to G and GAC with capacities of 108.5 and 110.7 mg/g, respectively. Pseudo-second-order kinetic model with 88.7% and Langmuir isotherm with 74% had the best fitting with the data studied. Baujat plot revealed that two studies (ID: 75 and 12) had the minimum influence on adsorption capacity with the highest dffits and cook's distance. According to the pooled data, the mean adsorption capacity varied between 140.90 and 208.25, with a mean of 174.57 mg/g across all studies. The results of Egger's test (t = 0.1332, p = 0.0844) and Begg's test (z = 0.8458, p = 0.3977) were not statistically significant, suggesting that no potential publication bias existed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2020.126238DOI Listing
July 2020

Human health risk assessment of trace elements in drinking tap water in Zahedan city, Iran.

J Environ Health Sci Eng 2019 Dec 20;17(2):1163-1169. Epub 2019 Dec 20.

1Health Promotion Research Center, Zahedan University of Medical Sciences, Zahedan, Iran.

Daily intake of elements through the consumption of drinking water, due to its detrimental effects, is accounted for an important concern. Although the health risk assessment of heavy metals in different water sources has extensively carried out in various studies, the effect of age and the concentration of all trace elements in drinking tap water have neglected. Therefore, this study was conducted to evaluate the concentrations of heavy metals, e.g., As, Cd, Cr, Ni, Pb, B, Al, Hg, Mn, Zn, Cu, Fe, Se and Ba in the drinking tap water of Zahedan city and to estimate their non-carcinogenic and carcinogenic effects. Moreover, this is the first research in Iran that has also been dedicated to complete investigation on daily intakes of trace elements in tap water. A total of 155 samples of drinking water were randomly taken from the tap water and were analyzed using ICP-OES device. The estimation of the carcinogenic and non-carcinogenic risks of analyzed elements was carried out based on the guidelines of the U.S EPA. The hazard index (HI) values for children and adult age groups were 9.84E-01 and 4.22E-01, respectively. The cumulative Excess Lifetime Cancer Risk (ELCR) for carcinogenic trace elements was in range of tolerable carcinogenic risk 10 to10 and for all carcinogenic elements were in the order of Pb > Cd > Cr. It also detected that the total carcinogenic risks of the Cd, As and Cr in water samples through the ingestion route are at the levels of "low risk" and "low-medium risk".
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40201-019-00430-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985301PMC
December 2019

Households' behavior and social-environmental aspects of using bag dustbin for waste recovery in Tehran.

J Environ Health Sci Eng 2019 Dec 18;17(2):1067-1076. Epub 2019 Dec 18.

Department of Environmental Engineering, School of Water Science Engineering, Ahvaz Chamran University, Ahvaz, Iran.

The suitable dustbin can cause a significant increase in household participation in separated dry waste at production source and recycling rate. This study was conducted on 100 households in Tehran for two weeks for households' wastes without any intervention. After two weeks, the tough-flexible bag dustbins were delivered to the families. At the next stage, by analysing the separated dry wastes by households, comparing the cost of new bag dustbin with plastic garbage bags, and completing some questionnaires, it was concluded that about 92% of households believed that waste bag dustbin was much more accessible and hygienic. The use of plastic garbage bags was decreased an average by 2, after using new bag dustbins. Moreover, the use of bag dustbins has more cost-effectiveness rather than plastic bags (about 54%). Before and after the intervention, the source separation and recovery rate was 0.19 and 0.18, respectively. The amount of wet waste in the waste bag dustbin was decreased to 62.26% after the intervention. The decrease of wet waste in the separated dry waste enhanced the quality of recycled materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40201-019-00421-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985419PMC
December 2019

Fixed bed adsorption column studies and models for removal of ibuprofen from aqueous solution by strong adsorbent Nano-clay composite.

J Environ Health Sci Eng 2019 Dec 19;17(2):753-765. Epub 2019 Jul 19.

3Center for Solid Waste Research (CSWR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.

In this study, ibuprofen was removed using a strong nano-clay-composite based on cloisite 15A, PVP and β-cyclodextrin (CD@clay-PVP) adsorbent through a fixed-bed column system. Chemically modified nano-clay was characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and XRD. Different input situations were evaluated and included adsorbent bed height, initial concentrations, and the impact of the flow rate on the adsorbent. The various mathematical models employed to predict the breakthrough curve and model parameters include Thomas, bed-depth service time (BDST), Yoon-Nelson, and Clark. The characteristics of parameters related to the models were obtained by linear and nonlinear regression to design the process for the columns. Based on error analysis and adsorption conditions, all of the models are identical in describing the adsorption fixed-bed columns.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40201-019-00392-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985314PMC
December 2019

Trihalomethanes in urban drinking water: measuring exposures and assessing carcinogenic risk.

J Environ Health Sci Eng 2019 Dec 12;17(2):619-632. Epub 2019 Jun 12.

1Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Trihalomethanes (THMs) have been proven to be potentially genotoxic and mutagenic for human. The aim of this study was to characterize the THMs spatiotemporal distribution and its carcinogenic risk potential in Ardabil water distribution system. Water samples were collected over consecutive months from twenty-six points in the city of Ardabil from April 2016 to March 2017. The potential carcinogenic risk assessment of THMs was evaluated quantitatively with uncertainty assessment based on Monte-Carlo simulation technique. The results showed that the mean concentrations of bromodichloromethane, Chloroform, dibromochloromethane and Bromoform in water consumed by residents were 101.97 ± 58.51, 85.18 ± 47.79, 51.67 ± 29.57 and 11.89 ± 6.64 μg/L, respectively, during the sampling period. According to the result of this study, the concentrations of THMs were higher in summer in comparison with other seasons. The mean values of lifetime cancer risks for residents through ingestion, inhalation and dermal contact are 2.85×10-4, 6.46×10-7, and 1.26×10-7, respectively. The lifetime cancer risks for residents through ingestion was found to be 285 times more than the minimum or negligible level set by US.EPA (1.0×10-6) and for dermal contact and inhalation lower than the minimum or negligible level set by US.EPA. The results of the present research may contribute to inform the decision makers of drinking water supply system about the role of water quality in the health of consumers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40201-019-00374-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985399PMC
December 2019

Enhanced fluoride removal over MgFeO-chitosan-CaAl nanohybrid: Response surface optimization, kinetic and isotherm study.

Int J Biol Macromol 2020 Apr 16;148:574-590. Epub 2020 Jan 16.

Department of Environmental Engineering, Bushehr Branch, Islamic Azad University, Bushehr, Iran. Electronic address:

In this work an effective adsorption route was developed for fluoride removal from aqueous solution. For this purpose MgFeO, MgFeO-chitosan and a three component nanocomposite of were synthesized and used. Characterization of the sorbents was performed with FESEM, TEM, FTIR, BET, VSM, SEM mapping and XRD techniques. Effective parameters on the adsorption process such as pH, contact time, adsorbent dosage and fluoride concentration was optimized by response surface methodology (RSM) using Box-Behnken design (BBD). Results showed that solution pH is a significant factor in fluoride adsorption with all adsorbents. However, adsorbent dosage was a significant factor when MgFeO-chitosan and three component adsorbents are employed. Kinetic study was performed based on pseudo-first order, pseudo-second order, intraparticle diffusion and Elovich model and results confirmed fluoride adsorption followed the pseudo-second order model. Isotherm study was studied at two concentration ranges of 0.5-10 mg/L and 10-100 mg/L of fluoride ions. Results showed that adsorption process followed Langmuir model with capacity of 263.15 mg/g. Regeneration was performed with NaOH solution (0.1 mol/L). It was found that removal percentage is in the range of 91-73% in five cycles of adsorption and regeneration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijbiomac.2020.01.143DOI Listing
April 2020

Health Risk Assessment of Dermal Exposure to Heavy Metals Content of Chemical Hair Dyes.

Iran J Public Health 2019 May;48(5):902-911

Department of Environmental Health Engineering, Iranshahr University of Medical Sciences, Iranshahr, Iran.

Background: Contamination of hair dyes to heavy metals can threaten consumer's health. We investigated the concentrations of some important heavy metals in hair dyes and evaluates their non-carcinogenic effects.

Methods: The most commonly used hair dyes were determined through questioners and 32 samples were collected from the market of Tehran in 2014. The concentration of 10 heavy metals (Fe, Ag, Co, Cr, Mn, Ba, Cd, Cu, Pb, and Al) was determined using ICP-MS. Based on the obtained data from distributed questionnaires and Monte Carlo simulation, the exposure to the evaluated heavy metals was estimated. Besides, using hazard quotient (HQ) and chronic hazard (HI), the risk of non-carcinogenic effects of investigated hair dyes consumption was specified.

Results: Results indicated the average concentrations of Al, Ba, and Fe as 0.54, 0.86, and 1.19 mg kg and those of Cd, Cu, and Pb as 0.45, 61.32, and 185.34 μg kg, respectively. Pb with HQ of 7.46e-4 had the highest risk and Fe with HQ of 3.4e-6 had the lowest level of risk. Among the investigated dyes, the ones made by Iran (HI=2.8e-4) and the dark brown color (HI=1.93e-4) had the highest level of risk among all the studied samples.

Conclusion: Two indices of HI and HQ showed that heavy metal contents in the investigated samples had not probable non-carcinogenic risks for the consumers of these products.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6717416PMC
May 2019

Developing environmental health indicators [EHIs] for Iran based on the causal effect model.

J Environ Health Sci Eng 2019 Jun 27;17(1):273-279. Epub 2019 May 27.

Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Background: Environmental health monitoring and its effects on health are very important in health systems. Relationship between environment and health can be done by simplifying data in understandable indicators for people and policy-makers. The present study presents the general framework for formulating environmental health quality index for Iran.

Methods: This study was implemented through expert panel at two levels: indicator domain determination and domain specific variables selection. Domain specific variables were selected based on the Driving force-Pressure-State-Exposure-Effect-Action (DPSEEA) framework from the list of national and international variables.

Results: Seven environmental health issues [air quality, drinking water, sewage disposal, food, radiation management and housing and human settlements] were determined, and three variables were selected for air quality, 8 variables for water quality, 5 variables for sanitation, 1 variable for food quality, 3 variables for housing and human settlements, 4 variables for solid waste management and 3 variables for radiation management.

Conclusions: Environmental health indicators determination based on the causal effect model leads to a better understanding of the relationship between the environment and health by simplifying data in an understandable format for public and improves prioritization of policy-making in the environmental health. In this study, environmental health indicators for Iran were proposed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40201-019-00346-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6582035PMC
June 2019

Arsenate removal from aqueous solutions using micellar-enhanced ultrafiltration.

J Environ Health Sci Eng 2019 Jun 19;17(1):115-127. Epub 2019 Feb 19.

4Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Education City, Qatar Foundation, Doha, Qatar.

In this study, arsenate (As-V) removal using micellar enhanced ultrafiltration (MEUF) modified by cationic surfactants was studied by a dead-end polyacrylonitrile (PAN) membrane apparatus. The UF membrane has been produced by a phase inversion process. The prepared membrane was characterized and analyzed for morphology and membrane properties. The influence of operating parameters such as initial concentrations of As-V, surfactants, pH, membrane thickness, and co-existing anions on the removal of As-V, surfactant rejection, and permeate flux have been studied. The experimental results show that from the two different cationic surfactants used the CPC (cetyl-pyridinium chloride) efficiency (91.7%) was higher than that of HTAB (hexadecyltrimethyl-ammonium bromide) (83.7%). The highest As-V removal was 100%, and was achieved using initial feed concentrations of 100-1000 μg/L at pH 7 with a membrane thickness of 150 μm in a dead-end filtration system. This efficiency for As-V removal was similar to that obtained using a cross-flow system. Nevertheless, this flux reduction was less than the reduction achieved in the dead-end filtration process. The PAN fabricated membrane in comparison to the RO and NF processes selectively removed the arsenic and the anions, in the water taken from the well, and had no substantial effect on the cations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40201-018-00332-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6582139PMC
June 2019

Landfill site selection using a hybrid system of AHP-Fuzzy in GIS environment: A case study in Shiraz city, Iran.

MethodsX 2019 14;6:1454-1466. Epub 2019 Jun 14.

Department of Natural Resources, School of Environmental Sciences, Tehran University, Tehran, Islamic Republic of Iran.

Landfilling with simplicity and economic advantages is the most common element for waste management in both developed and developing countries. Landfill site selection in a proper way is an important municipal planning process which prevent environmental issues including water pollution imposed for insanitary landfills. The present research was developed to exhibit a simplified method of multi criteria decision making (MCDM) and Fuzzy memberships in GIS environment to ascertain best landfill sites for Shiraz county, located south of Iran. 15 most common sub-criteria, documented in literature and implicated by Iranian environmental protection organization (IEPO) including surface water, ground water, land use, distance to well, soil type, slope, protected area, fault in environmental group, residential area, road, airport, village, infrastructure, historical area, wind direction in socio-economical group were selected and the weight of each criterion was determined based on expert's knowledge with use of analytical hierarchy process (AHP). The results of the present research are as follows: •Distance to residential area and groundwaters with weight of 0.36 and 0.28 were recognized as the most important criteria for landfill site selection.•The six suitable areas for landfill in Shiraz county is 1.003% of total area equal to 8710 ha.•AHP and Fuzzy memberships has a great potential and ability for landfill site selection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mex.2019.06.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6593174PMC
June 2019

Bioaccessibility analysis of toxic metals in consumed rice through an in vitro human digestion model - Comparison of calculated human health risk from raw, cooked and digested rice.

Food Chem 2019 Nov 3;299:125126. Epub 2019 Jul 3.

Department of Environmental Health, School of Public Health, Tehran University of Medical Science, Tehran, Iran; Center for Research Methodology and Data Analysis (CRMDA), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

The health risk assessment of exposure to toxic metals through the consumption food crops is very important. The present study was aimed to investigate the bioaccessibility of toxic metals (including arsenic, lead and cadmium) in rice through an in vitro gastrointestinal digestion model, and assess health risks associated with these metals in raw, cooked and digested rice. Total and bioaccessible concentration of metals were measured by introducing the prepared samples into the inductively coupled plasma-optical emission spectroscopy. Based on the results, the bioaccessible toxic metals in gastric phase were significantly higher than that in both oral and small intestinal phases. The estimated concentrations of these metals in the raw and cooked rice are very far from the actual exposure state. Therefore, to assess the extent of health risks associated with the subjected toxic metals through the rice consumption, the actual exposure value of the metals (bioaccessible value) should be considered.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.foodchem.2019.125126DOI Listing
November 2019

An innovative swimming pool water quality index (SPWQI) to monitor and evaluate the pools: design and compilation of computational model.

Environ Monit Assess 2019 Jun 19;191(7):448. Epub 2019 Jun 19.

Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

This research aimed to develop an index known as swimming pool water quality index (SPWQI) for quantifying the water pollution potential. The index is a quantitative tool to show the data on the water quality of swimming pools consistently. It makes summarizing the complex data on water quality possible and paves the way for its communication to the general public and decision makers. In this study, the SPWQI has been formulated according to the literature review and Delphi method. According to literature review and the total judgment of the panelist (23 experts specialized in environmental health engineering), 13 physicochemical and biological parameters along with their weights were selected for inclusion in the SPWQI. The results indicated the possibility of calculating a single numerical value (i.e., SPWQI), which indicates the combined effect of significant selected parameters on water quality. In addition, biological composition (47%) had a strong preference weighting than physical and chemical parameters in evaluating the index. Next, it was attempted to implement a novel and user-friendly mathematical model for evaluating the SPWQI. Then, the model accuracy and performance was confirmed by a case study. Overall, it could be said that the assessment of SPWQI sheds light on the concurrent power of several pollutants and can help the authorities to decide upon water quality management and treatment approaches.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10661-019-7577-yDOI Listing
June 2019

The Relation of Cancer Risk with Nitrate Exposure in Drinking Water in Iran.

Iran J Public Health 2019 Feb;48(2):362-364

Department of Environmental Health Engineering, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6556186PMC
February 2019

Designing and modeling of a novel electrolysis reactor using porous cathode to produce HO as an oxidant.

MethodsX 2019 1;6:1305-1312. Epub 2019 Jun 1.

Department of Pharmaceutics, Faculty of Pharmacy, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.

The entry of toxic organic pollutants and resistant to biodegradation has increased the concern about human health. The use of advanced oxidation (AO) processes to degrade these pollutants has been developing. One of the AO processes is based on the use of hydrogen peroxide in removing resistant organic pollutants. This study aimed to develop a new reactor capable of producing HO in the solution. Therefore, a porous electrode made of stainless steel with the capability of air injection in the electrode center was used. The 30 cm rod graphite electrodes were also used as an anode electrode in a 4000 ml reactor. The effects of variables, including current density (30-40 mA/cm), time (10-30 min), and electrolyte concentration (12-17 mM/L) on the amount of HO production were evaluated by design under response surface methodology using software. The results of this study showed that HO can be produced at the electrode surface of porous cathode under optimal conditions of 36 mA/cm current density, 16 mM/l electrolyte concentration, in 23 min, and in the amount of 34 ppm. Using a porous cathode electrode causes the maximum contact among the solution, water, and air, and increases the production of HO. The release of resistant organic compounds to the waste water is a serious problem to the environment. By the application of the (EO)reactor with the ability to produce HO, this issue is resolved. Furthermore, this technique is applied for non-selective degradation of the toxic organic compounds. •The electro-oxidation process is a useful method for destruction of persistent organic matter from wastewater.•Due to use of porous cathode in this method, contact between the electrode and the sewage is at its maximum level which increases the efficiency and speed of sewage treatment.•This method can produce HO as a high potential oxidant that can reduce persistent organic properties of sewage and make the wastewater suitable for biological treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mex.2019.05.036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558086PMC
June 2019

Prevalence of diarrheal illness and healthcare-seeking behavior by age-group and sex among the population of Gaza strip: a community-based cross-sectional study.

BMC Public Health 2019 Jun 7;19(1):704. Epub 2019 Jun 7.

Department of Research, Directorate General of Human Resources Development, Ministry of Health, Gaza Strip, Palestine.

Background: In the Gaza strip, diarrhea is one of main reasons for children visiting primary healthcare centers. Hence, we investigate predictors of the diarrheal illness and health care-seeking behavior among different age groups.

Methods: This community-based cross-sectional survey was conducted from August 2017 to June 2018 among 1857 households. A pretested structured questionnaire included information about socio-demographic, sanitation, hygiene, source of water, diarrheal illness, and seeking healthcare in households was administered to head of household. To achieve representativeness for the five Gaza's governorates, a cluster random sampling was applied.

Results: Of the 1857 household's heads, 421 (22.7%) reported an episode of diarrhea during the 48 h preceding the interview resulting an overall prevalence rate of 3.8 per 100 individuals. The prevalence of diarrhea was statistical significant greater in males (5.4/100) compared to females (1.3/100) in all age groups (p <  0.05). Socio-demographic, economic, water, sanitation, and hygiene factors were predictors of the diarrheal illness and seeking of non-professional healthcare for diarrhea illness treatment among. A transition behavior from professional to non-professional and vice versa in seeking healthcare in each diarrheal episode was found.

Conclusions: We recommend improving the status of water, sanitation, and hygiene in the Gaza strip's households to reduce diarrhea among the population of Gaza strip. Community sensitization about the importance of seeking care at primary health centers because treatment of children is available for free or in low costs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12889-019-7070-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6555956PMC
June 2019

A systematic literature review for some toxic metals in widely consumed rice types (domestic and imported) in Iran: Human health risk assessment, uncertainty and sensitivity analysis.

Ecotoxicol Environ Saf 2019 Jul 25;176:64-75. Epub 2019 Mar 25.

Research Center for Environmental Determinants of Health (RCEDH), Kermanshah University of Medical Sciences, Kermanshah, Iran.

In present study we aimed to investigate the literature in the form of systematic review to determinate the concentrations of some toxic metals (arsenic, lead, and cadmium) in widely consumed rice brands in Iran and their related health risks. International and Iranian national databases were searched carefully with appropriate keywords for papers on toxic metal contamination of rice from Agust-2000 to Agust-2018. Initially, 560 articles were found, of which only the 50 papers fit the inclusion criteria and were selected for further analysis. The Monte Carlo Simulation was applied to generate missing data (mean, standard deviation, data distribution and sample size) of toxic metal concentration in some papers. Then, statistical analysis, health risk assessment, and uncertainty and sensitivity analysis were performed. The results indicated that approximately 88% of rice consumed in Iran (including Iranian, Pakistani and Indian rice) do not meet the national standard and WHO/FAO guideline requirements and their related health risks are unacceptable. The risks of arsenic and lead in Indian rice and cadmium in Iranian rice were considerably higher than others. In conclusion, according to our findings, In conclusion, it is necessary to prevent toxic metals contamination of rice by modifying cultivation patterns and, also, prevent low-quality rice brands to be imported.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ecoenv.2019.03.072DOI Listing
July 2019

Advantages and disadvantages of different pre-cooking and cooking methods in removal of essential and toxic metals from various rice types- human health risk assessment in Tehran households, Iran.

Ecotoxicol Environ Saf 2019 Jul 18;175:128-137. Epub 2019 Mar 18.

Department of Environmental Health, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

The aim of present study was to evaluate the effects of different pre-cooking and cooking methods on the concentration of toxic (As, Cd and Pb) and essential (Fe, Cu, Co and Zn) metals in widely consumed rice types by Tehran households, Iran. In this regard, a total of 90 samples were obtained from Iranian, Pakistani and Indian rice brands (30 samples from each brand), and were examined in order to determine the concentration of toxic metals including As, Cd, Pb, Fe, Zn, Co and Cu using ICP-OES. Among these rice brands, the most contaminated one was selected in order to evaluate the effects of washing and soaking processes in different time points (1, 5 and 12 h), as well as different cooking methods (Rinsing and Kateh) in reducing the concentration of subjected metals. Nine samples were analyzed for each process, which were 54 samples in total. Our results show that the preparation and cooking methods applied for all rice brands (except for Indian rice) could effectively reduce the non-carcinogenic risk associated with these metals to the acceptable level; however, this is not true about the carcinogenic risk associated with arsenic. Finally, according to our findings it can be concluded that all cooking methods can lead to considerable removal of rice toxic metals (this is partially true about all available rice brands in Iran), however, a large amount of essential metals were also eliminated by these methods. Moreover, after cooking of different rice types in Iran, this food has still carcinogenic risk associated with arsenic.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ecoenv.2019.03.056DOI Listing
July 2019

Comparative investigation of argon and argon/oxygen plasma performance for Perchloroethylene (PCE) removal from aqueous solution: optimization and kinetic study.

J Environ Health Sci Eng 2018 Dec 2;16(2):277-287. Epub 2018 Oct 2.

1Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Purpose: The aim of this study is evaluation of the perchloroethylene degradation from aqueous solutions by non-thermal plasma produced in dielectric barrier discharge reactor in two different scenarios: first plasma generated with 225 cc/min mixture of oxygen and argon flow (12% gas ratio of O/Ar), and in the second scenario plasma generated with 225 cc/min of pure argon gas.

Methods: Design studies were performed using response surface methodology and central composite design. All experiments with the selected levels of independent parameters including the initial concentration of perchloroethylene (5-100 mg/L), voltage (20-5 kv) and contact time (15-180 s) was implemented, and 29 tests were proposed by using response surface methodology and central composite design was performed in two experimental scenarios.

Results: Results showed that the Pseudo first-order kinetics coefficient of perchloroethylene degradation in the mixture of oxygen and argon and pure argon scenario under the optimum conditions were 0.024 and 0.016 S respectively. Results conveyed that in order to achieve the highest removal efficiency (100%), the values of contact time, perchloroethylene concentration and voltage variables were predicted 169.55 s, 74.3 mg/l, 18.86 kv respectively in mixture of oxygen and argon scenario and also were predicted 203 s, 85.22 mg/l, 20.39 kv respectively in pure argon scenario.

Conclusions: In the recent study dielectric barrier discharge was an efficient method for perchloroethylene removal with both oxygen an argon mixture and pure argon as input gas. Both input voltage and reaction time has positive effect on perchloroethylene removal; but initial perchloroethylene concentration has negative effect on perchloroethylene removal. Comparison of two plasma scenarios with different input gas shown that plasma generated by mixture of oxygen and argon gas was more powerful and had higher removal efficiency and degradation kinetics than the plasma generated by pure argon gas.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s40201-018-0316-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6277337PMC
December 2018

Endotoxin removal from aqueous solutions with dimethylamine-functionalized graphene oxide: Modeling study and optimization of adsorption parameters.

J Hazard Mater 2019 04 12;368:163-177. Epub 2019 Jan 12.

Biomaterials Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran 1417614411, Iran; Department of Pharmaceutical Biomaterials and Medicinal Biomaterials Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

Novel graphene oxide (GO)-based adsorbent embedded with epichlorohydrin (ECH) as a coupling agent and dimethylamine (DMA) as a ligand (GO-ECH-DMA) were prepared and employed for endotoxin removal from aqueous solutions. The physicochemical properties of nanocomposite were fully characterized. The model attributed to batch adsorption process was optimized employing response surface methodology (RSM) via various parameters such as pH, GO-ECH-DMA dosage, and contact time and endotoxin concentration. The p-value with low probability (<0.00001), determination coefficient (R=0.99) and the non-significant lack of fit (p > 0.05) showed a quadratic model with a good fit with experimental terms. The synergistic effects of the linear term of contact time and GO-ECH-DMA dosage on endotoxin removal were significant. The optimum condition for endotoxin removal was obtained at pH of 5.52, GO-ECH-DMA dosage of 21 mgL, contact time of 56 min and endotoxin concentration of 51.3 endotoxin units per milliliter (EUmL). The equilibrium was the better explained by Langmuir isotherm with the maximum monolayer adsorption capacity of 121.47 EUmg-1, while the kinetics of the endotoxin adsorption process was followed by the pseudo-second-order model. The adsorbent could be recycled with NaOH. The possible mechanisms of endotoxin adsorption were proposed by hydrogen-bonding, π-π stacking, and electrostatic interaction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2019.01.028DOI Listing
April 2019

The reduction of toxic metals of various rice types by different preparation and cooking processes - Human health risk assessment in Tehran households, Iran.

Food Chem 2019 May 19;280:294-302. Epub 2018 Dec 19.

Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

In this study, the effect of washing, soaking (1, 5 and 12 h), and cooking rice methods including Rinsed (boiling in excess water) and Kateh (conventional) cooking on the reduction of the arsenic (As), lead (Pb), and cadmium (Cd) were evaluated. The results showed that the rinsed cooking has higher efficiency for removal of toxic metals (As = 42.3%, Pb = 42.9% and = 27.6%) than Kateh method (As = 26.9%, Pb = 26.9% and = 20.9%). Additionally, by increasing of rice soaking time from 1 to 12 h, the toxic metals removal was increased up to 37.1%, 42.6% and 16.6% for As, Pb and Cd, respectively. Although the toxic metals reduction was such that the non-carcinogenic risk was regarded as acceptable level after all processes, for arsenic, these reductions did not lower the carcinogenic risk to an acceptable level. Finally, it is suggested that Tehran households, after washing and soaking to 5 h, then cook it by rinse method.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.foodchem.2018.12.060DOI Listing
May 2019