Environmental Research Center - 2015

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Title: Cadmium removal from aqueous solution by green synthesis iron oxide nanoparticles with tangerine peel extract

Author(s): Ehrampoush, MH; Miria, M; Salmani, MH; Mahvi, AH

Abstract: Background: The adsorption process by metal oxide nanoparticles has been investigated an effective agent for removing organic and inorganic contaminants from water and wastewater. In this study, iron oxide nanoparticles were synthesized in the presence of tangerine peel extract as adsorbent for cadmium ions removal from contaminated solution. Iron oxide nanoparticles prepared by co-precipitation method and tangerine peel extract was used to prevent accumulation and reduce the diameter of the particles. Effect of various parameters such as contact time, pH, metal concentration and adsorbent dosage was determined on the removal efficiency.
Results: The different concentrations of tangerine peel had an impact on the size of nanoparticles. As, increasing the concentration of tangerine peel extract from 2 to 6 % the average size of synthesized iron oxide nanoparticles decreased 200 nm to 50 nm. The maximum removal of cadmium ions (90 %) occurred at pH of 4 and adsorbent dose of 0.4 g/100 ml. Adsorption of cadmium ions by synthesized iron oxide nanoparticles followed Freundlich adsorption model and pseudo-second-order equation.
Conclusion: The cadmium ions are usually soluble in acidic pH and the maximum removal of cadmium by green synthesis iron oxide nanoparticles was obtained in the pH of 4, so these nanoparticles can be a good adsorbent for the removal of cadmium from wastewater.

Title: The Interaction between Heterotrophic Bacteria and Coliform, Fecal Coliform, Fecal Streptococci Bacteria in the Water Supply Networks

Author(s): Amanidaz, N; Zafarzadeh, A; Mahvi, AH

Abstract: Background: This study investigated the interaction between heterotrophic bacteria and coliform, fecal coliforms, fecal streptococci bacteria in water supply networks.
Methods: This study was conducted during 2013 on water supply distribution network in Aq Qala City, Golestan Province, Northern Iran and standard methods were applied for microbiological analysis. The surface method was applied to test the heterotrophic bacteria and MPN method was used for coliform, fecal coliform and fecal streptococci bacteria measurements.
Results: In 114 samples, heterotrophic bacteria count were over 500 CFU/ml, which the amount of fecal coliform, coliform, and fecal streptococci were 8, 32, and 20 CFU/100 ml, respectively. However, in the other 242 samples, with heterotrophic bacteria count being less than 500 CFU/ml, the amount of fecal coliform, coliform, and fecal streptococci was 7, 23, and 11 CFU/100ml, respectively. The relationship between heterotrophic bacteria, coliforms and fecal streptococci was highly significant (P<0.05). We observed the concentration of coliforms, fecal streptococci bacteria being high, whenever the concentration of heterotrophic bacteria in the water network systems was high.
Conclusion: Interaction between heterotrophic bacteria and coliform, fecal coliforms, fecal streptococci bacteria in the Aq Qala City water supply networks was not notable. It can be due to high concentrations of organic carbon, biofilms and nutrients, which are necessary for growth, and survival of all microorganisms.

Title: Characterization of saline dust emission resulted from Urmia Lake drying

Author(s): Gholampour, A; Nabizadeh, R; Hassanvand, MS; Taghipour, H; Nazmara, S; Mahvi, AH

Abstract: Compared with common dust storms, saline dust storms transport high concentrations of fine-grain saline and alkaline material. The saline dust storm differs from common dust storm, especially considering the sources of the suspended particulate matter (PM), chemical composition, grain size, and circulation processes. Atmospheric particulate matters (TSP, PM10, PM2.5, and PM1) and their water-soluble ions were concurrently measured at two sites located at north and southeast part of Urmia lake from January 2013 to September 2013. Particulate matters (PMs) were measured using high volume sampler and HAZ-DUST EPAM-5000 particulate air monitors. In both of the sampling sites, the highest concentration of PM was observed during the summer season (521.6, 329.1, 42.6, and 36.5 for TSP, PM10, PM2.5, and PM1, respectively). A total of 11 inorganic water-soluble ions in the TSP and PM10 were identified by ion chromatography (IC). No statistically significant difference was found between PMs ions concentrations of two sampling sites. The average of the total measured water-soluble ions in the sampling sites was 28.75 +/- 12.9 mu g/m(3) (11.9 +/- 4.8% of total TSP mass) for TSP and 14.65 +/- 7.1 mu g/m(3) (8.7 +/- 4.4 of total PM10 mass) for PM10. Among all detected ions, sulfate was the dominant constituent followed by nitrate and sodium. This study showed that the water soluble salts compose 3-20% of the total mass of TSP and PM10. The PCA analysis showed that saline particulates formed from Urmia lake bed were the dominant source (57.6 %) of TSP. In addition, saline particulates together with crustal materials resulted from resuspension were the main source (59.9%) of PM10.

Title: Optimization of sonochemical degradation of tetracycline in aqueous solution using sono-activated persulfate process

Author(s): Safari, GH; Nasseri, S; Mahvi, AH; Yaghmaeian, K; Nabizadeh, R; Alimohammadi, M

Abstract: Background: In this study, a central composite design (CCD) was used for modeling and optimizing the operation parameters such as pH, initial tetracycline and persulfate concentration and reaction time on the tetracycline degradation using sono-activated persulfate process. The effect of temperature, degradation kinetics and mineralization, were also investigated.
Results: The results from CCD indicated that a quadratic model was appropriate to fit the experimental data (p < 0.0001) and maximum degradation of 95.01 % was predicted at pH = 10, persulfate concentration = 4 mM, initial tetracycline concentration = 30.05 mg/L, and reaction time = 119.99 min. Analysis of response surface plots revealed a significant positive effect of pH, persulfate concentration and reaction time, a negative effect of tetracycline concentration. The degradation process followed the pseudo-first-order kinetic. The activation energy value of 32.01 kJ/mol was obtained for US/S2O82- process. Under the optimum condition, the removal efficiency of COD and TOC reached to 72.8 % and 59.7 %, respectively. The changes of UV-Vis spectra during the process was investigated. The possible degradation pathway of tetracycline based on loses of N-methyl, hydroxyl, and amino groups was proposed.
Conclusions: This study indicated that sono-activated persulfate process was found to be a promising method for the degradation of tetracycline.

Title: Removal of noxious Cr (VI) ions using single-walled carbon nanotubes and multi-walled carbon nanotubes

Author(s): Dehghani, MH; Taher, MM; Bajpai, AK; Heibati, B; Tyagi, I; Asif, M; Agarwal, S; Gupta, VK

Abstract: The adsorption capacity of two efficient adsorbents namely MWCNTs and SWCNTs for the rapid removal of noxious Cr (VI) ion from the polluted aqueous source was well studied and investigated. The impact of several influential parameters such as contact time, initial pH, initial Cr (VI) ion concentrations and the adsorption capacity of the adsorbent in the presence of competing anion was well elucidated and optimized. It was observed that the removal of efficiency of Cr (VI) ion depends on the pH of solution and the maximum efficiency was noticed at pH 2.5. Furthermore, the uptake of Cr (VI) ion was hindered in the presence of the competing anion, SO42-. Experimental equilibrium data were fitted to four different isotherm models by linear regression method, however, the adsorption equilibrium data were well interpreted by the Langmuir model. The maximum adsorption capacity of Cr (VI) ion by MWCNTs and SWCNTs was 1.26 and 2.35 mg/g respectively, which is calculated by the Langmuir isotherm model. Kinetic studies are well suited and found in good agreement with pseudo-second order. The results evidently indicated that MWCNTs and SWCNTs would be suitable adsorbents for Cr (VI) ion in wastewater under specific conditions.

Title: Heavy metals removal from aqueous environments by electrocoagulation process- a systematic review

Author(s): Bazrafshan, E; Mohammadi, L ; Ansari-Moghaddam, A; Mahvi, AH

Abstract: Heavy metals pollution has become a more serious environmental problem in the last several decades as a result releasing toxic materials into the environment. Various techniques such as physical, chemical, biological, advanced oxidation and electrochemical processes were used for the treatment of domestic, industrial and agricultural effluents. The commonly used conventional biological treatments processes are not only time consuming but also need large operational area. Accordingly, it seems that these methods are not cost-effective for effluent containing toxic elements. Advanced oxidation techniques result in high treatment cost and are generally used to obtain high purity grade water. The chemical coagulation technique is slow and generates large amount of sludge. Electrocoagulation is an electrochemical technique with many applications. This process has recently attracted attention as a potential technique for treating industrial wastewater due to its versatility and environmental compatibility. This process has been applied for the treatment of many kinds of wastewater such as landfill leachate, restaurant, carwash, slaughterhouse, textile, laundry, tannery, petroleum refinery wastewater and for removal of bacteria, arsenic, fluoride, pesticides and heavy metals from aqueous environments. The objective of the present manuscript is to review the potential of electrocoagulation process for the treatment of domestic, industrial and agricultural effluents, especially removal of heavy metals from aqueous environments. About 100 published studies (1977-2016) are reviewed in this paper. It is evident from the literature survey articles that electrocoagulation are the most frequently studied for the treatment of heavy metal wastewater.

Title: Turbidity removal from aqueous environments by Pistacia atlantica (Baneh) seed extract as a natural organic coagulant aid

Author(s): Bazrafshan, E; Mostafapour, FK; Ahmadabadi, M; Mahvi, AH

Abstract: Coagulation/flocculation, as an important step in water treatment processes, is applied for turbidity removal of raw water coming from suspended particles and colloidal material. In this study, the ability of Pistacia atlantica seed extract, as a natural organic coagulant aid along with ferric chloride for turbidity removal from synthetic solutions, was investigated. Coagulation ability of this coagulant was assessed by the use of standard jar test measurement. The influence of several operating parameters such as, pH (2-12), coagulant dose (2-35mg/L), natural coagulant aid dose (0.1-5.0ml/L), and initial turbidity (20-200 NTU), were investigated. The optimum pH for removal of turbidity by coagulation process using P. atlantica seed extract was found 9-10 with coagulant dose 1ml/L (in combination with FeCl3 at dose 2mg/L). The results obtained with synthetic solutions revealed that the most effective removal efficiency of turbidity (97.43%) was achieved with natural coagulant dose 0.4ml/L and FeCl3 10mg/L at pH 9. In addition, the highest removal efficiency was obtained at higher initial turbidities. According to the results of this study and with respect to the abundance of this tree in various regions of Iran, especially in mountain areas, its use as a natural coagulant for turbidity removal from aqueous environments is possible and viable specifically for rural areas and small communities.

Title: FLUORIDE REMOVAL FROM AQUEOUS ENVIRONMENTS BY ZnCl2-TREATED EUCALYPTUS LEAVES AS A NATURAL ADSORBENT

Author(s): Bazrafshan, E; Khoshnamvand, N; Mahvi, AH

Abstract: In the present study, the ability of ZnCl2-treated Eucalyptus leaves (70% dry leaves and 30% ZnCl2) to act as a natural adsorbent for fluoride (F) removal from synthetic solutions was investigated by the use of standard jar test measurements of the effects of the operating parameters of pH, adsorbent dose, contact time, temperature, and initial F concentration. The F adsorption capacity and its removal efficiency increased as the pH of the solution increased up to pH 6 when the maximum adsorption was observed (84.1 mg F/g of adsorpent with an adsorpent dosage of 0.5 g/L and an initial F concentrations of 50 mg/L). The F removal efficiency increased with increasing adsorbent dose, contact time, and F concentration. It was found that the data fitted to Langmuir model (R-2=0.8469) better than the Freundlich model (R-2=0.5995). The Standard Defluoridation Capacity for ZnCl2-treated Eucalyptus leaves (70% dry leaves and 30% ZnCl2) was estimated to be 3.5 mg F/g of ZnCl2-treated Eucalyptus leaves.

Title: THE EFFECT OF TEMPERATURE, WATER HARDNESS, AND EXPOSURE TIME ON FLUORIDE TOXICITY IN THE AQUATIC ENVIRONMENT

Author(s): Shamsollahi, HR; Zolghadr, Z; Mahvi, AH; Hosseini, SS; Mossavi, SN

Abstract: Many studies have measured fluoride toxicity for aquatic organisms with various levels of water quality including the examination of spot samples and the presence of interfering factors. In the present study, the actual fluoride toxicity, the fluoride LC50, was determined without interfering factors present and then after modelling the effects of changes in temperature, water hardness, and exposure time. Fluoride toxicity decreased with increased water hardness and increased with increased temperature and exposure time. This information may help with industrial effluent discharge planning in recipient waters that have a high fluoride content so that fluoride toxicity can be avoided.

Title: REACTIVE DYES (R. BLUE 19 AND R. RED 120) REMOVAL BY A NATURAL COAGULANT: MORINGA OLEIFERA

Author(s): Jafari, A; Mahvi, AH

Abstract: In this study, Moringa oleifera seed extract was applied as coagulant under different pH values (2.5 - 9.5), coagulant dosages (200-600 mg/L), initial dye concentrations (50-300 mg/L) and different settling times (0-60 minutes) for R. Blue 19 and R. Red 120 dyes removal. Results revealed that with increase in pH (from 2.5 to 9.5), removal efficiency decreased from 95% to 87.3% for R. Blue 19 and from 97.2% to 62% for R. Red 120. By increasing coagulant dosage to 400 mg/L, removal efficiencies increased up to 93% for both dyes. Higher dosages (more than 400 mg/L) could not achieve more than 93% removal of the dyes. No suspension of formed flocs nor desorption of the dyes was observed after long settling times up to 24 hours. Moringa oleifera did not change the pH of solution through experiments. This natural coagulant revealed a high capacity in reactive dyes removal.

Title: DETERMINATION OF COPPER, NICKEL AND CHROMIUM CONTENTS IN CULTIVATED TEA IN NORTH OF IRAN

Author(s): Mohagheghian, A; Mahvi, AH; Shekoohiyan, S; Koolivand, A; Nazmara, S; Aslani, H; Brahmand, MB; Dobaradaran, S

Abstract: The aim of this study is to investigate the copper (Cu), nickel (Ni) and chromium (Cr) levels in cultivated black tea in north of Iran. The infusions of Cu, Cr and Ni in tea after 5, 15 and 60 min brewing time were measured. Results showed that the highest (2.32 +/- 2.63 mg/kg) and the lowest (2.16 +/- 1.84 mg/kg) mean levels of Cu were observed after 15 and 60 min, respectively. The mean levels of Ni and Cr at 60 min were the highest (13.72 +/- 8.09 mg/kg and 1.30 +/- 1.03 mg/kg, respectively) and at 5 min were the lowest (6.80 +/- 4.95 mg/kg and 0.88 +/- 0.79 mg/kg, respectively).

Title: Assessment of bioaerosol contamination (bacteria and fungi) in the largest urban wastewater treatment plant in the Middle East

Author(s): Niazi, S; Hassanvand, MS; Mahvi, AH; Nabizadeh, R; Alimohammadi, M; Nabavi, S ; Faridi, S; Dehghani, A; Hoseini, M; Moradi-Joo, M; Mokamel, A; Kashani, H; Yarali, N ; Yunesian, M

Abstract: Bioaerosol concentration was measured in wastewater treatment units in south of Tehran, the largest wastewater treatment plant in the Middle East. Active sampling was carried out around four operational units and a point as background. The results showed that the aeration tank with an average of 1016 CFU/m(3) in winter and 1973 CFU/m(3) in summer had the greatest effect on emission of bacterial bioaerosols. In addition, primary treatment had the highest impact on fungal emission. Among the bacteria, Micrococcus spp. showed the widest emission in the winter, and Bacillus spp. was dominant in summer. Furthermore, fungi such as Penicillium spp. and Cladosporium spp. were the dominant types in the seasons. Overall, significant relationship was observed between meteorological parameters and the concentration of bacterial and fungal aerosols.

Title: Characterization of PAHs and metals in indoor/outdoor PM10/PM2.5/PM1 in a retirement home and a school dormitory

Author(s): Hassanvand, MS; Naddafi, K; Faridi, S; Nabizadeh, R; Sowlat, MH; Momeniha, F; Gholampour, A; Arhami, M; Kashani, H; Zare, A; Niazi, S; Rastkari, N ; Nazmara, S ; Ghani, M ; Yunesian, M

Abstract: In the present work, we investigated the characteristics of polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s in indoor/outdoor PM10, PM2.5, and PM1 in a retirement home and a school dormitory in Tehran from May 2012 to May 2013. The results indicated that the annual levels of indoor and outdoor PM10 and PM2.5 were much higher than the guidelines issued by the World Health Organization (WHO). The most abundant detected metal(loid) s in PM were Si, Fe, Zn, Al, and Pb. We found higher percentages of metal(loid) s in smaller size fractions of PM. Additionally, the results showed that the total PAHs (PAHs) bound to PM were predominantly (83-88%) found in PM2.5, which can penetrate deep into the alveolar regions of the lungs. In general, carcinogenic PAHs accounted for 40-47% of the total PAHs concentrations; furthermore, the smaller the particle size, the higher the percentage of carcinogenic PAHs. The percentages of trace metal(loid) s and carcinogenic PAHs in PM2.5 mass were almost twice as high as those in PM10. This can most likely be responsible for the fact that PM2.5 can cause more adverse health effects than PM10 can. The average BaP-equivalent carcinogenic (BaP-TEQ) levels both indoors and outdoors considerably exceeded the maximum permissible risk level of 1 ng/m(3) of BaP. The enrichment factors and diagnostic ratios indicated that combustion-related anthropogenic sources, such as gasoline-and diesel-fueled vehicles as well as natural gas combustion, were the major sources of PAHs and trace metal(loid) s bound to PM.

Title: Fabrication and characterization of a polysulfone-graphene oxide nanocomposite membrane for arsenate rejection from water

Author(s): Rezaee, R; Nasseri, S; Mahvi, AH; Nabizadeh, R; Mousavi, SA; Rashidi, A; Jafari, A; Nazmara, S

Abstract: Background: Nowadays, study and application of modified membranes for water treatment have been considered significantly. The aim of this study was to prepare and characterize a polysulfone (PSF)/graphene oxide (GO) nanocomposite membrane and to evaluate for arsenate rejection from water.
Materials and methods: The nanocomposite PSF/GO membrane was fabricated using wet phase inversion method. The effect of GO on the synthesized membrane morphology and hydrophilicity was studied by using FE-SEM, AFM, contact angle, zeta potential, porosity and pore size tests. The membrane performance was also evaluated in terms of pure water flux and arsenate rejection.
Results: ATR-FTIR confirmed the presence of hydrophilic functional groups on the surface of the prepared GO. FE-SEM micrographs showed that with increasing GO content in the casting solution, the sub-layer structure was enhanced and the drop like voids in the pure PSF membrane changed to macrovoids in PSF/GO membrane along with increase in porosity. AFM images indicated lower roughness of modified membrane compared to pure PSF membrane. Furthermore, contact angle measurement and permeation experiment showed that by increasing GO up to 1 wt%, membrane hydrophilicity and pure water flux were increased. For PSF/GO-1, pure water flux was calculated about 50 L/m(2)h at 4 bar. The maximum rejection was obtained by PSF/GO-2 about 83.65 % at 4 bar. Moreover, it was revealed that arsenate rejection depended on solution pH values. It was showed that with increasing pH, the rejection increased.

Title: CFD modeling of incinerator to increase PCBs removal from outlet gas

Author(s): Yaghmaeian, K; Jaafarzadeh, N; Nabizadeh, R; Dastforoushan, G; Jaafari, J

Abstract: Incineration of persistent organic pollutants (POPs) is an important alternative way for disposal of this type of hazardous waste. PCBs are very stable compounds and do not decompose readily. Individuals can be exposed to PCBs through several ways and damaged by their effects. A well design of a waste incinerator will convert these components to unharmfull materials. In this paper we have studied the design parameters of an incinerator with numerical approaches. The CFD software Fluent 6.3 is used for modelling of an incinerator. The effects of several baffles inside the incinerator on flow distribution and heat is investigated. The results show that baffles can reduce eddy flows, increase retaining times, and efficiencies. The baffles reduced cool areas and increased efficiencies of heat as maximum temperature in two and three baffle embedded incinerator were 100 and 200 degrees C higher than the non-baffle case, respectively. Also the gas emission leaves the incinerator with a lower speed across a longer path and the turbulent flow in the incinerator is stronger.

Title: Hierarchical distance-based fuzzy approach to evaluate urban water supply systems in a semi-arid region

Author(s): Yekta, TS; Khazaei, M; Nabizadeh, R; Mahvi, AH; Nasseri, S; Yari, AR

Abstract: Hierarchical distance-based fuzzy multi-criteria group decision making was served as a tool to evaluate the drinking water supply systems of Qom, a semi-arid city located in central part of Iran. A list of aspects consisting of 6 criteria and 35 sub-criteria were evaluated based on a linguistic term set by five decision-makers. Four water supply alternatives including "Public desalinated distribution system", "PET Bottled Drinking Water", "Private desalinated water suppliers" and "Household desalinated water units" were assessed based on criteria and sub-criteria.
Data were aggregated and normalized to apply Performance Ratings of Alternatives. Also, the Performance Ratings of Alternatives were aggregated again to achieve the Aggregate Performance Ratings. The weighted distances from ideal solution and anti-ideal solution were calculated after secondary normalization. The proximity of each alternative to the ideal solution was determined as the final step. The alternatives were ranked based on the magnitude of ideal solutions.
Results showed that "Public desalinated distribution system" was the most appropriate alternative to supply the drinking needs of Qom population. Also, "PET Bottled Drinking Water" was the second acceptable option. A novel classification of alternatives to satisfy the drinking water requirements was proposed which is applicable for the other cities located in semi-arid regions of Iran.
The health issues were considered as independent criterion, distinct from the environmental issues. The constraints of high-tech alternatives were also considered regarding to the level of dependency on overseas.

Title: HYPERTENSION AND FLUORIDE IN DRINKING WATER: CASE STUDY FROM WEST AZERBAIJAN, IRAN

Author(s): Aghaei, M; Karimzade, S; Yaseri, M; Khorsandi, H; Zolfi, E; Mahvi, AH

Abstract: Hypertension is a major public health challenge in Iran and its detection and control are vitally important to reduce the risk of myocardial infarction and cerebrovascular accident. Fluoride can be a risk factor for hypertension and, in this cross-sectional study, the effects on the prevalence of hypertension of high (3.94 mg F/L) and low (0.25 mg F/L) fluoride exposure via drinking water were investigated in two areas in West Azerbaijan province, Iran. The number of persons studied, aged 20-65 yr, was 897 (male: 453; female: 444) in the high fluoride area and 1981 (male: 945; female: 1036) in the low fluoride area. Cases were excluded who had aetiological factors known to contribute to hypertension, such as smoking, age >65 yr, a family history of hypertension, lack of mobility, cardiovascular disease, and obesity. In the high fluoride area, compared to the low fluoride area, hypertension, without known aetiological factors, was increased (p<0.05) in females aged 50-59 yr and decreased (p<0.05) in the combined group of males and females aged 40-49 yr. Because of the varying results of the studies in this topic, further research is recommended.

Title: Removal of acid 4092 dye from aqueous solution by zinc oxide nanoparticles and ultraviolet irradiation

Author(s): Dehghani, MH; Mahdavi, P

Abstract: One of the most important environmental concerns is that of water contamination from industrial effluent and dyes used in the textile industry are a primary cause of such contamination. Most conventional methods of wastewater treatment are insufficient to remove these pollutants, so tests were done on a method of removing acid red 4092 dye from wastewater. Tests investigated advanced oxidation processes, based on hydroxyl radical production, were used as an effective method to remove this type of pollutant. The purpose of this study was to investigate the removal of acid red 4092 dye by zinc oxide nanoparticles and ultraviolet radiation (UV-150 W). Dye concentration was measured before and after treatment using a spectrophotometer (Perkin-Elmer Lambada 25-UV/vis). Experiments were performed in a batch photo-reactor on synthetic wastewater with concentrations of 0.5, 1.0, 1.5, and 2 mg/L. The study investigated the effects of factors such as initial dye concentration, irradiation time, dose of catalyst, and pH on the removal efficiency of acid red 4092 dye by the photocatalytic process in the presence of zinc oxide nanoparticles. The dye samples were irradiated by ultraviolet radiation for 2-12 min. Experiments showed that the best result was obtained in the treatment with concentration of dye = 0.5 mg/L, radiation time = 12 min, pH 5, and dosage of catalyst = 0.2 g/L. Results of the study showed that with increasing concentration of acid red 4092 dye (2 mg/L), removal percentage was decreased and with increasing radiation time (12-14 min), removal percentage was increased (100%). This research determined that the photocatalytic process of zinc oxide nanoparticles in the UV reactor effectively removed the acid red 4092 dye from an aqueous solution.

Title: Ultrafiltration of natural organic matter from water by vertically aligned carbon nanotube membrane

Author(s): Jafari, A; Mahvi, AH; Nasseri, S; Rashidi, A; Nabizadeh, R; Rezaee, R

Abstract: In this study vertically aligned carbon nanotubes (VA-CNT) was grown on anodized aluminum oxide (AAO) substrate. The synthesized AAO-CNT membrane was characterized using Raman spectroscopy, field emission scanning electron microscopy (FESEM), contact angle and BET. The pure water flux, humic acid (HA) (as representative of natural organic matters) rejection and fouling mechanism were also evaluated. The fabricated membrane has pore density of 1.3 x 10(10) pores per cm(2), average pore size of 20 +/- 3 nm and contact angle of 85 +/- 8(o). A significant pure water flux of 3600 +/- 100 L/m(2).h was obtained at 1 bar of pressure by this membrane due to the frictionless structure of CNTs. High contact angle exhibited the hydrophobic property of the membrane. It was revealed that HA is primarily rejected by adsorption in the membrane pores due to hydrophobic interactions with HA. Flux decline occurred rapidly through both cross flow and dead end filtration of the HA. Based on the blocking laws, internal pore constriction is dominant fouling mechanism in which HA adsorbs in membrane pores results in pores blockage and flux decline.

Title: Determination of aluminum and zinc in infusion tea cultivated in north of Iran

Author(s): Ghoochani, M; Shekoohiyan, S; Yunesian, M; Nazmara, S; Mahvi, AH

Abstract: To determine aluminum and zinc levels in black tea cultivated in north of Iran, 105 black tea samples were collected from the tea growing regions of Guilan and Mazandaran provinces and were analyzed for Al and Zn concentration of tea infusion. Contents of all elements were analyzed three times separately by using an Inductively Coupled Plasma Atomic Emission Spectrometry (ICP - AES). The solubility of Al and Zn in infusions at 5, 15 and 60 min with boiling water showed that the mean level of Al in the third infusion was the highest (262.09 mg/kg) and in the first infusion was the lowest (169.40 mg/kg). The mean level of Zn in the third infusion was the highest (51.40 mg/kg) and in the second infusion was the lowest (48.33 mg/kg). The analysis of results also showed that the location factor influences the contents of these metals at different infusions.

Title: Fenton regeneration of humic acid-spent carbon nanotubes

Author(s): Naghizadeh, A; Nasseri, S; Mahvi, AH; Rashidi, A; Nabizadeh, R; Kalantary, RR

Abstract: Carbon nanotubes (CNTs) are known as efficient sorbents for removal of organic compounds from aquatic solutions. In the present study, the efficiency of Fenton solution for regeneration of CNTs exhausted with humic acid was studied. CNTs were produced using chemical vapor deposition method. The molar ratios of Fe2+ to H2O2 as 0.5:10, 1:10, and 2:10 were used. The saturation cycles were continued up to five stages. Results of Fenton regeneration showed higher regeneration efficiency (65.4%) for 2:10 M ratio comparing to other molar ratios after five cycles of regeneration. Slight decrease in adsorption capacity after each regeneration cycle was observed which may be due to the deposition of decomposed residues in CNT pores, which blocked the carbon porosity and decreased the specific surface area. In conclusion, the Fenton regeneration especially at higher Fe2+:H2O2 molar ratios showed a possibility as an alternative to chemical and thermal regenerations of CNTs.

Title: Equilibrium and thermodynamics studies for decolorization of Reactive Black 5 (RB5) by adsorption onto MWCNTs

Author(s): Bazrafshan, E; Mostafapour, FK; Rahdar, S; Mahvi, AH

Abstract: At present study, multi-walled carbon nanotubes were used as an adsorbent for Reactive Black 5 (RB5) removal from aqueous solutions. The influence of important parameters including initial pH, concentration of dye, contact time, adsorbent dosage, and temperature has been investigated in order to find the optimum adsorption conditions. The results show that all the parameters have a strong effect on the adsorption of RB5 onto adsorbent. Adsorption kinetics was best described by the pseudo-second-order model. In addition, equilibrium data were better represented by Freundlich isotherm among Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich equilibrium isotherm models. The negative values of free-energy change confirmed the feasibility of the process and the spontaneous nature of adsorption. Furthermore, from the magnitude of H, the process was found to be endothermic physisorption.

Title: Heavy metals determination in honey samples using inductively coupled plasma-optical emission spectrometry

Author(s): Aghamirlou, HM; Khadem, M; Rahmani, A; Sadeghian, M; Mahvi, AH; Akbarzadeh, A; Nazmara, S

Abstract: Background: Honey contains a complex mixture of carbohydrates and other minor substances. Elements are minor constituents of honey that may threaten the human health in excess concentrations. So, determining the metals in honey helps its quality control as a food product. The aim of this study was to determine the concentrations of some metals in Iranian honey.
Methods: This study was performed in four regions of Ardabil, a province of Iran. Honey samples (n = 25) were digested in microwave oven by nitric acid and hydrogen peroxide, then analyzed using inductively coupled plasma-optic emission spectrophotometry (ICP-OES).
Results: No significant differences were observed in cadmium, zinc, nickel, and chromium levels between regions (P > 0.05). Zinc was the most abundant metal in honey samples (1481.64 mu g/kg). Some metals had higher concentrations in the East region because of existence more industries there. The highest mean of lead level was 935.48 mu g/kg in the East and the lowest was 205.4 mu g/kg in the South region. The concentrations of metals were compared with recommended limits for foods. Some of them were higher than standard levels (lead) and some were lower than those (cadmium).
Conclusions: Metals are released into the environment through their use in industrial processes and enter the food chain from uptake by plants from contaminated soil or water. Metals concentration in various places depends on many variables, leading to their different concentrations in honey. Some control measures like the quality control of food products, monitoring the soil in agricultural regions and limiting the use of fertilizers are recommended.

Title: Adsorption of bisphenol A (BPA) from aqueous solutions by carbon nanotubes: kinetic and equilibrium studies

Author(s): Dehghani, MH; Mahvi, AH; Rastkari, N; Saeedi, R; Nazmara, S; Iravani, E

Abstract: Contamination of water resources by bisphenol A (BPA) is considered as a critical environmental problem. In this study, the feasibility of BPA adsorption from aqueous solutions by single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) was investigated in a batch system. In order to define the kinetic and isotherm of the reaction, specific experiments were performed at BPA concentrations of 5-50 and 2-50 mg/L, respectively. The BPA uptake by both adsorbents was found to be rapid; also, uptake reached to equilibrium in 60 min for all of the cases. The kinetic data of both adsorbents were also described by the saturation model (R-2 > 0.99) as well as the pseudo-second-order rate equation (R-2 > 0.99). Based on the saturation rate model, the maximum reaction rates (k(m)) of BPA adsorption by the SWCNTs and MWCNTs were in the ranges of 0.023-0.089 mg/L min and 0.013-0.060 mg/L min, respectively. In the pH range of 3-11, the optimized condition of pH for BPA adsorption by both the adsorbents was 9.0. The isotherm data of the SWCNTs and MWCNTs were found to be in the best fitness with the Freundlich-Langmuir and Langmuir isotherm models (R-2 > 0.99), respectively. According to the Langmuir model, the maximum adsorption capacities of BPA by the SWCNTs and MWCNTs were, respectively, 71 and 111 mg/g. Therefore, it can be concluded that the MWCNTs were more efficient adsorbent for BPA than the SWCNTs.

Title: EFFECT OF FLUORIDE IN DRINKING WATER ON BIRTH HEIGHT AND WEIGHT: AN ECOLOGICAL STUDY IN KERMAN PROVINCE, ZARAND COUNTY, IRAN

Author(s): Aghaei, M; Derakhshani, R; Raoof, M; Dehghani, M ; Mahvi, AH

Abstract: The present study evaluated the association between maternal exposures to drinking water fluoride and birth height and weight in 35 villages and towns in Zarand county, in Iran. Birth height and weight data on 492 infants born during 2013 were obtained from Zarand Central Hospital records. Results from the Pearsons correlation test showed that there is a nearly strong positive correlation between the babies height and the drinking water fluoride (R-2=0.479, r=0.69, p<0.001) and a mild positive correlation between the birth weight and the drinking water fluoride (R-2=0.196, r=0.44, p<0.001). We found that exposure to fluoride at concentrations higher than the WHO drinking water guideline of a "desirable" upper limit of 1.5 mg/L was not associated with lower birth height and weight and that lower birth height and weight were observed with lower drinking water fluoride concentrations. Because of the importance of this issue, it is reasonable to conduct more studies.

Title: The estimation of per capita loadings of domestic wastewater in Tehran

Author(s): Mesdaghinia, A; Nasseri, S ; Mahvi, AH; Tashauoei, HR; Hadi, M

Abstract: The amount of wastewater characteristics loading is one of the main parameters in the design of wastewater collection and treatment systems. The generation per capita per day (GPCD) of wastewater characteristics was estimated by analyzing the monthly data of nine wastewater treatment plants in Tehran, capital city of Iran. GPCD values were calculated from measured collected wastewater flow, the population and concentration data. The results indicated the values of 32.96 +/- 1.91, 49.25 +/- 2.49, 37.31 +/- 2.44, 6.77 +/- 0.53, 1.96 +/- 0.11, 92.23 +/- 5.68, 2.07 +/- 0.39 and 128.96 +/- 6.69 g/d. cap of GPCD for BOD5, COD, TSS, TKN, P, TDS, ON and TS, respectively, for Tehrans wastewater. The per capita estimated for the wastewater production and treatment were determined to be 186.06 +/- 7.85 and 136.72 +/- 5.43 L/d. cap, respectively. It is estimated that about 504 m(3)/d and 346 m(3)/d of sludge, will be produced and waste as excrement raw sludge, respectively, in Tehran. Simple regression models were presented the relationships such as the change of collected and treated wastewater with population and changes of GPCD parameters with each other. It was revealed that the Tehrans wastewater may be classified as highly degradable, but during recent decades its Biodegradability Index (BI) has been reduced up to 15%. The new suggested revised per capita parameters can be used for design purposes in Tehran, and possibly, in areas with similar characteristics, substituting the classical values obtained from foreign textbooks. These values could help in designing more accurate treatment systems and may lower the required capacity for the treatment of wastewater up to 40% in Tehran.

Title: Trace analysis of some organophosphorus pesticides in rice samples using ultrasound-assisted dispersive liquid-liquid microextraction and high-performance liquid chromatography

Author(s): Sharafi, K; Fattahi, N; Mahvi, AH; Pirsaheb, M; Azizzadeh, N; Noori, M

Abstract: An ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of a floating organic drop method followed by high-performance liquid chromatography was developed for the extraction, preconcentration, and determination of trace amounts of organophosphorus pesticides in rice samples. Variables affecting the performance of both steps were thoroughly investigated. Some effective parameters on extraction were studied and optimized. Under the optimum conditions, recoveries for rice sample are in the range of 58.0-66.0%. The calibration graphs are linear in the range of 4-800 mu g/kg and, limits of detection and limits of quantification are in the range of 1.5-3 and 4.2-8.5 mu g/kg, respectively. The relative standard deviation for 50.0 mu g/kg of organophosphorus pesticides in rice sample are in the range of 4.4-5.1% (n = 5). The obtained results show that proposed method is a fast and simple method for the determination of pesticides in cereals.

Title: Heavy Metal Contamination in Street Dusts with Various Land Uses in Zahedan, Iran

Author(s): Kamani, H; Ashrafi, SD; Isazadeh, S; Jaafari, J; Hoseini, M; Mostafapour, FK; Bazrafshan, E; Nazmara, S; Mahvi, AH

Abstract: A total of 78 street dust samples (75 within city and 3 from suburban) were collected from different areas with various land use within the city of Zahedan in November 2013 at the end of a long dry period. After digestion, the concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were measured by using ICP-OES. The degree of pollution by heavy metals was assessed with respect to the background concentration by calculation and comparison of the pollution index, integrated pollution index (IPI) and enrichment factor (EF). The mean IPI values (aggregate of six heavy metals) in commercial, high traffic, industrial, urban park, and residential were 3.65, 2.76, 1.68, 1.53 and 1.25, respectively. The results of EF analysis showed almost all sampled urban land use types to be enriched in heavy metals compared with sampled background levels, suggesting heavy metals contamination of street dust in the urban center is from anthropogenic sources.

Title: Quantitative and qualitative characteristics of condensate water of home air-conditioning system in Iran

Author(s): Alipour, V; Mahvi, AH; Rezaei, L

Abstract: The global atmosphere is a huge and renewable water resource which contains about 14,000km(3) of water vapor. The aim of this study was to investigate the water produced by the air conditioners installed Bandar-e-Abbas (BA) and its chemical and microbiological quality of this water. Moreover, it was also important to specify the best use of the water. In a nine-month period, 66 samples were taken in four clusters of BA, based on distance to shore and population and vehicle traffic. Quantity was measured by volumetric method; turbidity, alkalinity (ALK), total hardness, dissolved solids (TDS), and electrical conductivity (EC) were tested in laboratory; and counting of bacteria and fungi was done. SPSS 19.0 for Windows was used for data analysis. Mean of produced water was 21.3-47.6L/d;, and mean for pH, turbidity, EC, TDS, ALK, and total hardness was 6.75-6.89, 2.33-2.55NTU, 37.8-45.6 mu S/cm, 28.8-33.3mg/L, 34.3-38.2mg/L as CaCO3, and 18.2-21.6mg/L as CaCO3, respectively. Legionella pneumophila is present in 22% of samples and Staphylococcus aureus, Micrococcus sp., Corynebacterium diphtheria Bacillus sp., and Pseudomonas were 21, 13, 18, 13, and 13%, respectively. Observed fungi in the tested samples were 23, 18, 16, 15, 14, and 14% for Penicillium, Aspergillus, Cladosporium, Alternaria, Mucor, and Trichoderma, respectively.. The water quality is suitable to many municipal uses and due to the significant volume, the planning of utilizing this significant amount of free water would be economically justified.

Title: Photocatalytic degradation of tetracycline using nanosized titanium dioxide in aqueous solution

Author(s): Safari, GH; Hoseini, M; Seyedsalehi, M; Kamani, H; Jaafari, J; Mahvi, AH

Abstract: The aim of the study was to investigate the degradation kinetics of tetracycline antibiotic by nanosized titanium dioxide under ultraviolet irradiation. Enhancement of photocatalysis by addition of Hydrogen peroxide was also evaluated. Various experimental parameters such as initial tetracycline concentrations, initial titanium dioxide concentration, initial pH, reaction times, initial Hydrogen peroxide concentrations, as well as water matrix using ultrapure water, drinking water and secondary effluent were investigated. The initial rate of photocatalytic degradation of tetracycline well fitted the Langmuir-Hinshelwood kinetic model (R-2 = 0.9926) with a reaction rate constant of 1.4 mg/L min. The degradation rate depended on initial tetracycline concentration and initial pH. The degradation rate also increased with higher titanium dioxide density and reached a plateau at titanium dioxide concentration of 1.0 g/L. The tetracycline degradation rate was higher in drinking water compared to ultrapure water. The addition of Hydrogen peroxide to titanium dioxide suspension significantly enhanced the tetracycline degradation rate and substantially reduced the time required to degrade 100 % of tetracycline. Changes of chemical oxygen demand values during photolysis indicated that tetracycline transformed into intermediate products without complete mineralization. The ultraviolet visible spectra obtained before and after ultraviolet irradiation in the presence of titanium dioxide can indicate the formation of 4a, 12a-anhydro-4-oxo-4-dimethylaminotetracycline.

Title: Simultaneous nitrification and denitrification using a polypyrrole/microbial cellulose electrode in a membraneless bio-electrochemical system

Author(s): Hossini, H; Rezaee, A; Ayati, B; Mahvi, AH

Abstract: In this study, the feasibility of ammonium and total nitrogen (TN) removal from aqueous solution using a simultaneous nitrification and denitrification process was studied in a membraneless (single chamber) bio-electrochemical system with a novel electrode. The main objectives were to synthesize a polypyrrole/microbial cellulose (PPy/MC) composite and utilize it as a novel electrode material. To determine the mechanical properties of PPy/MC, the tensile strength and Youngs modulus were investigated. A biofilm was prepared using the fabricated electrode during the first few weeks. Effective parameters such as initial ammonium concentrations (NH4+ similar to 15-150 mg N L-1), HRT (6-72 h), carbon/ nitrogen ratio (C/N ratio similar to 0-4), current intensity (2-10 mA), and pH (6.5-8.5) were evaluated. The following optimum values were obtained: HRT, 24 h; C/N ratio, 2; electric current, 6 mA; and pH, 7-7.5 at a constant ammonium concentration of 77.77 mg N L-1. It can be concluded from the experimental data that under optimal conditions about 97.42 and 62.47% of ammonium and TN were removed successfully, respectively.

Title: INFLUENCE OF SELECTED ANIONS ON FLUORIDE REMOVAL IN ELECTROCOAGULATION/ELECTROFLOTATION

Author(s): Maleki, A; Mahvi, AH; Daraei, H; Rezaei, R; Meihami, N; Mohamnnadi, K; Zandi, S

Abstract: Fluoride removal by electrocoagulation/electrofloatation was investigated as an alternative defluoridation method. Batch experiments with aluminum electrodes were used to investigate, with response surface methodolgy (RSM), genetic algorithm (GA), and the artificial neural network approach (ANN), the effects on defluoridation by electrocoagulation/electrofloatation of the concentration of usual five co-existing anions (Br-, CI-, NO3-, SO42-, and PO42-), and the operational parameters of initial pH, applied electrical current intensity, initial fluoride concentration, and process time. The results demonstrated that the type and concentration of co-existing anions, as well as various operational parameters, had a significant effect on the efficiency of defluoridation by electrocoagulation/electrofloatation.

Title: Elimination and detoxification of sulfathiazole and sulfamethoxazole assisted by laccase immobilized on porous silica beads

Author(s): Rahmani, K; Faramarzi, MA; Mahvi, AH; Gholami, M; Esrafili, A; Forootanfar, H; Farzadkia, M

Abstract: This study assessed the immobilization of laccase on CPC silica beads and removal of two sulfonamides, sulfathiazole (STZ) and sulfamethoxazole (SMZ), using free and immobilized laccase. The results showed that free laccase (1 U ml(-1)) removed 66% and 77% of SMZ and STZ, respectively, in the presence of 1-hydroxybenzotriazole (1 mM) as a laccase mediator after incubation at 40 degrees C for 1 h. Maximum enzymatic removal of both applied sulfonamides was achieved at a temperature of 50 degrees C and a pH of 5. At the elevated temperature of 70 degrees C, immobilized laccase removed 71.7% of KZ and 53% of SMZ. After ten cycles of removal experiments, 63.3% and 82.6% of the initial activity of the immobilized laccase toward SMZ and grz remained, respectively. A lower K-m value for STZ (0.056 mM) compared to that of SMZ (0.096 mM) confirmed a higher affinity of immobilized laccase toward STZ. A microtoxicity study of the inhibition of bacterial growth showed a decrease in toxicity of the laccase-treated sulfonamide solution.