فهرست مطالب بهناز دهر آزما

The discharge of dye-containing wastes by the dye-consuming industry causes irreparable damage to the environment and humans. Nowadays, the use of membrane separation technology is a new and applicable technology in dyes separation. However, membranes used in water and wastewater treatment suffer from problems such as permeability-selectivity trade-off as well as short life due to fouling. Therefore, in this study, we tried to improve the hydrophilicity and antifouling properties of polyvinylidene fluoride (PVDF) membranes by adding NiFe2O4-SiO2 nanocomposite and improve its performance in reactive dye separation from aqueous solution. For this purpose, first NiFe2O4-SiO2 nanoparticles were prepared by sol-gel method and then pure and NiFe2O4-SiO2/PVDF nanocomposite membranes were fabricated by wet phase inversion method and their performance was evaluated. The synthesized nanoparticles were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) methods. Membranes morphology, surface roughness, hydrophilicity of the membrane surface, separation performance, pure water flux, porosity and pore radius were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle tests (CA), pure water flux test (PWF) and gravimetric methods, respectively. Aqueous solution containing 10-30 ppm reactive red 120 was used as test wastewater. The results of the contact angle analysis showed that by addition of 0.3 wt.% NiFe2O4-SiO2 nanoparticles to the polymer matrix, the membrane contact angle decreased from from 77.5° in the pure membrane to 51.7° in the nanocomposite membrane. It showed an increase in membrane hydrophilicity. AFM results showed that the surface roughness decreased as NiFe2O4-SiO2 content increased in PVDF matrix. It was also found that nanocomposite membrane containing 0.3 wt.% NiFe2O4-SiO2 nanoparticles has the best separation performance among the other fabricated membranes and this membrane can reject reactive red 120 dye from aqueous solution completely (99.5%).

One of the main challenges of arid and desert regions is to control wind erosion that can cause significant economic and environmental damage. The present study aimed to stabilize erosion-prone soil using a vegetable mulch prepared from Eremurus spectabilis root powder. The effects of concentration and amount of mulch spraying on the soil erosion was investigated and the penetration and reduction of the thickness of the fixed layer against wind speeds of 6, 9, 12 and 15 m/s for 5 minutes was studied in the wind tunnel. Finally, EC, pH, salinity and other soil elements were tested to evaluate the environmental impact of mulching. The results showed that increasing the amount of mulch spraying results in more mulch penetration in the soil and increasing the mulch concentration, despite reducing the depth of its penetration into the soil due to increasing the amount of adhesion between the soil particles, its greater resistance to wind erosion. In addition, based on the results, mulches with concentrations of 0.2, 0.6 and 0.7% can stabilize the soil against the wind stream, up to maximum of 9, 12 and 15 m/s, respectively. Generally, the mulch is environmentally friendly and is an appropriate option for controlling the erosion of wind erosion-prone soil.

Contamination of water resources with petroleum products is an environmental problem in the recent decades. There are many different methods for remediation of aquatic environments. Adsorption is considered one of the most effective water remediation techniques. The availability and cost of absorbent is very important factor in the absorption process. In recent years, a wide range of materials were used as adsorbent for remediation of contaminated water. This study was performed to investigate the use of raw red mud as an adsorbent to remove COD from the soluble fraction of gasoline in aqueous solutions. The effects of different parameters including pH, contact time, adsorbent dose and initial concentration of gasoline on the removal process were investigated. It should be noted that all tests were repeated three times. The results showed that increasing pH, from 3 up to 11, increases the efficiency of COD reduction by the sorbent. According to the results, pH of 7 was selected as the optimal pH. The efficiency of COD reduction in contact times of 2.5, 5, 10, 15, 20, 25, 30, 60 and 120 minutes were studied. The COD reduction by raw red mud occurred quickly at the first step, then proceeds at a slower rate until equilibrium achieved within 15 minutes. Therefore, 15 minutes was considered as the optimum contact time. The effect of adsorbent dosage on the removal of COD of the solution for the values of 1, 2, 5, 10, 15, 20, 50 and 100 g/L was studied. The results showed that with the increasing of adsorbent dosage, the removal rate was increased. Based on the results, the optimal dosage of 10 g/L of raw red mud adsorbent was selected. The COD removal experiments were performed for the initial concentrations of 1%, 2%, 5%, 10% and 20% of gasoline. Removal of COD at low concentrations (1%) was close to 100%. Increasing the initial concentration of pollutant in the aqueous solution decreased the removal rate. Maximum removal of COD (%100) was occurred at the optimum conditions of pH = 7, contact time = 15 min, adsorbent dose = 10 g/L, and initial concentration of pollutant = %1. In order to determine the mechanism of adsorption of pollutants to the surface of raw red mud adsorbent, Langmuir, Freundlich and D-R isotherm models were evaluated. Results of the isotherm studies showed a high consistency (R2 = 0.98) with Langmuir isotherm model. It means that adsorption of gasoline on the surface of raw red mud is occurred as single layer, on the homogeneous surface of adsorbent and limited number of adsorbent active sites. Zero order, Pseudo first order and Pseudo second order kinetic models were investigated to determine the rate of the gasoline adsorption on the adsorbent surface. The kinetics of adsorption process was followed a pseudo-second-order model with a correlation coefficient of 0.99. Parameters such as short contact time, appropriate range for pH, acceptable absorption capacity, low cost and easy accessibility of the absorbent were the advantages of using red mud as an adsorbent to remove COD from soluble fraction of gasoline.

Remediation of contaminated soil by heavy metals is an important environmental issue which attracted many attentions and was evaluated by several methods. It is highly desirable to apply suitable remedial methods to reduce the risk of heavy metal contamination in soils. Development of new low-cost, efficient and environmental friendly remediation technologies is the main goal of the recent research activities in environmental science and technology. Using nanotechnology in removal of environmental pollutions is of modern and applicable methods. One of the early generations of nanoscale technologies in the field of environment is the use of iron nanoparticles as a ground for sorption of pollutants. These nanoparticles are nontoxic, inexpensive, and very strong absorbents.The aim of this study was to assess the effects of cadmium removal by soil washing with iron (III) oxide nano particles (Fe3O4), stabilized with Polyacrylic Acid (PAA) as nanofluid, on physicochemical characteristics of nanofluid and soil in two defined systems including batch and continuous flow configurations. For this purpose, after complete removal of Cd from the soil in both systems under the optimized conditions, the effects of removal on the physicochemical characteristics of soil and nanofluid including pH, electrical conductivity, and total dissolved solid were assessed. The results of XRD and SEM of soil samples and also zeta potential and size distribution of nanofluid, before and after the removal were investigated. To ensure the absence of other pollutants and elimination of any interaction between soil pollutants, the soil was prepared with clean standard materials and afterwards it was contaminated with cadmium solution prepared by cadmium nitrate. The optimum conditions for cadmium removal in the batch system was as follows: nanofluid concentration=500 ppm, pH=6.5, contact time=24 hr and the ratio of contaminated soil mass (gr) to nanofluid volume (mL) =1:150 . completely Cd removal in continouse flow configuration obtained in the following conditions: nanofluid concentration=500 ppm, pH=6.5, contact time=24 hr, and the flow rate =0.5 mL/min. Cadmium content in the nanofluid after remediation was determined with UV spectrophotometer by using APDC complexes in Tween 80 media. As per the results of this study, pH of the soil samples in the both batch and continuous flow configuration increased from 7.8 to 8.55 and 8.35 respectively. pH of nanofluid increased from 6.5 to 6.8 in the continuous flow configuration and 7.59 in the batch system. EC and TDS of the nanofluid decreased from 1.66 mS/cm and 1110 mg/L to 1.049 mS/cm and 699 mg/L in the continuous flow configuration and these parameters also reached respectively to 0.952 mS/cm and 635 mg/L in the batch system. Soil washing using Fe3O4 nanoparticle did not changed remarkably EC and TDS of the contaminated soil. Nanoparticles size with highest frequency in nanofluid before removal was 205 nmand after Cd removal reached to 23 nm and 29 nm in the continuous flow configuration and batch system respectively, which was an indication of the sorption of nanoparticles with grater size to the soil during the soil washing process. Zeta potential values of influent and effluent of nanofluid from continuous flow configuration and batch system were -61.5, -51.3, and -37.4 mV respectively. The structural changes of soil samples after removal in the both systems were assessed by XRD and SEM tests which confiremed the sorption of nanoparticles through the soil washing.

The aim of this research was the geochemical assessment of the groundwater quality and the evaluation of the distribution pattern of fluoride concentration in water resources of the region and their connection with the prevalence of dental fluorosis occurrence in the study area. To achieve to this goal six sediment and 22 water samples were taken and analyzed. Fluoride and phosphorous concentration were remarkably high (1400 ppm and 6231 ppm respectively) in basaltic-andesite unit. Water resources located in the southern part of old lake had the highest TDS (>6300mg/L) compared with the others. Fluoride content differ from 0.64-1.71mg/L and in 27% water samples were higher than allowable amount expressed by WHO (1.5mg/L). The health effects of fluoride were investigated on 210 students at the age of 7-16 years old. The results indicated that the fluoride concentration increased in the vicinity of the igneous rocks in water resources and also increased with the time residence. The concentration of fluoride in groundwater indicated the prevalence of dental fluorosis occurrence in the study area. The intensity of the disease revealed a meaningful correlation with the age and the male gender.

Soil, as one of the important elements of lithosphere and a part of ecosystem plays a crucial role in the life cycle. The goal of the presentresearch was to assess the influence of mineralization and abandoned Ay-ghalasi lead-zinc mine on the distribution of heavy metals andpollution in soil throughout the region. In this regard, 4 soil samples from tailing aroundthe mine and 23 residual soil samples from whole basin, 5 to 20 cm depth, considering the stratigraphy of the region and the distance to the mine were taken. The ICP-OES techniques were employed to determine the concentration of heavy metals (Pb, Zn, As, Cd, Cu, and Ag) in tailing and residual soil samples. The results show that the mean concentration of the heavy metals namely Pb, Zn, As, Cd, Cu, and Ag are 9187.2, 9392.3, 630.8, 0.2, 1005.9 and 61.1 respectively (all in mg/kg), which all are higher than the mean of world soil (MWs) except for the Cd, and also higher than the Dutch standard except for the Ag. In the vicinity of the mine, the concentrations of the metals are high, decreasing with the distance from the mine and the mineral vein. The concentration of Pb, Zn, As, and Ag in the control samples were higher than the MWs and the Dutch standard that is an indication of high background concentration of these elements in the region. In terms of Geo-accumulation Index, Enrichment Factor, Contamination Factor, Contamination Degree, and Pollution Load Index, the soil of the mine area shows high to infinite level of contamination. The elements Pb, Zn, Cu, and Ag have a high Pearson correlation factor.

Gotvand-Olya Dam is located near Gotvand City, 25 km north of Shooshtar city in Khozestan province. The present research aimed at investigation on the influence of outcrop formations in the reservoir on the water quality (concentration of anions and cations, TDS, EC, and concentration of heavy metal strontium) at three levels of 150, 200, and 250 m. The results showed that Gachsaran and Mishan formations release the highest concentrations of anions and cations to the water in all three levels respectively. Concentration of strontium was especially high in the Gachsaran formation which is justified by the significant correlation between strontium and basic and sulfate environments. According to the effect of solubility rate of the Gachsaran formation in the levels of 150 and 200 m on the water quality after filling the dam, EC of water was estimated to be 36632 and 28872 S/cm respectively which is classified as very high saline water. The results have also shown that the salinity drops significantly at the level of 250 m and the water at this level is classified as high saline water. In the case of the effect of the Mishan formation, the classification of water in the three levels are the same as Gachsaran formation, only EC at the level of 200 m is more than the two other levels.

Groundwater is of important drinking water resources. The quality of those water resources which are not affected by human activities, is characterized by local geological conditions. The present research was conducted in order to investigate the quality of water resources located in the south of Birjand plain, South Khorasan Province, using mass balance techniques. This research dealt with the quality assessment and the distribution pattern of physico-chemical parameters (anions and cations, pH, EC, TSS, TDS, and TH) in the groundwater resources in the region resulting in indentifying the contamination resources. Also, the origins of anions and cations in the groundwater resources as well as their connection with the geological characteristics of the region were evaluated by employing the mass balance techniques. The water sampling was performed systematically based on the distribution wells over the plain, with regard to the distances, and perpendicular to the topographical lines from the heights toward the lower plains down to the main river, 3 kilometers apart across the plain. In average, one third of whole wells in the study area were selected for sampling. The samples were taken during the end of dry season (October 2010) from 27 wells, 2 Qanats, and 1 spring. The cations (Na +, Ca+2, Mg+2, and K+), anions (HCO- 3, SO 4 2-, CO 3 2-, and Cl-), TSS, TDS, pH, and the total hardness of the water samples were measured in the Water, Soil, and Plant Laboratory, Kavosh Ab Shargh Khorasan Jonobi Engineering Services Co. To assess the quality of the water resources in the region, in this research the physicchemical properties of water samples were compared with ISIRI 1053 to identify the contaminated wells. The hardness of the samples was measured and the water resources types were identified using Piper Diagram. Also, through calculating the correlation factors and mass balance, hydrogeochemistry of water resources and probable origin of cations and anions were assessed. The results showed that 50%, 30%, and 10% of the groundwater resources are contaminated with magnesium, sodium, and chloride respectively. The petrological studies verified the presence of ophiolite sequence. A set of ultramafic rocks and basic magma (spilites) with wide developments in southern heights of Birjand plain which had the most effects on the water quality of the region. The water resources contaminations in the region may be due to the presence of listonites from the alteration of ultramafic rocks existed in highlands, upstream of the groundwater resources. 96% of groundwater resources are classified as very hard water. The types of groundwater vary from carbonated calcic in highlands to chloride sodic in downstream and east of the region due to high solubility of Na + and Cl- existing in the soil. %36.6 of water resources were chloric-sodic and the rest were classified as chloric-magnesic, bicarbonatesodic, and bicarbonate-magnesic. The correlation analysis of the parameters indicated that sodium has a very high correlation with chloride, potassium, and sulfate. The positive correlation of Mg 2+ with Ca2+ (+0.614) is an indication of the same origin for both ions. Also, EC with TH (+0.710) and Ca 2+ (+0.710) and TH with TSS (+0.641) show positive correlation. In general, these positive correlations indicate the common geogenic origin of cations and anions in water resources of the region. WATEVAL software was employed for calculating the mass balance using the concentration of anions and cations to find the effective parameters and origin of ions in the water resources. These calculations verify and emphasize on the influence of geological conditions of the region on hydrogeochemical properties of water resources of the plain. Mass balance analysis denotes that the origin of sodium and potassium could be the ion exchange process originated from weathering of mafic rocks (spilites) while the calcium may be released due to weathering of plagioclases of sub-volcanic mass, ferromagnesian minerals, carbonated listonite, and dissolution of limestone in the region.

This paper presents the criteria and applied methods in the screening of potential sites for the wastewater treatment plant of the Falavarjan district, northwest of Esfahan province. For this the nine parameters that were selected as main criteria, 7 parameters were considered to define the buffer zones in the natural and artificial terrains. At the first stage of the study, unsuitable zones were excluded and the weights of the main and subclasses were calculated using AHP method. Then, each parameter was mapped into a GIS system as an individual data layer. The final susceptibility map, which had been produced by overlapping all data layers, was divided into 4 categories. Then, the three top ranked areas were selected from the very suitable class. In order to locate the site with the minimum effect on the environment, the Leopold Matrix was used. Finally, area 1 was selected, by both TOPSIS and EIA, as the most preferable option for the construction of the wastewater treatment plant.

Coal mining changes the original geochemical equilibrium of rock bodies and by changing the oxidantion condition of the area; it may cause the release of elements from the coal and ambient rocks into the environment. In the present study, the effects of mining activities in Tazareh Mine Complex, located on 70km North West of Shahrood, were investigated. Concentrations of As, S, Cu, Fe, Hg, Sb, Pb, Zn, Sr and Se in the water resources, tailings and the coals excavated from the main tunnel of the mine were determined to find out the distribution of these elements in the groundwater. The coal in this region shows a high value of enrichment factor for Cu, Pb, As, Hg and Se (22.55, 77.01, 17.86, 44.64, 61.95, and 486.40, respectively). The tailing and face have much less enrichment factor for the above mentioned elements compared and the coal in the region. In terms of correlation among the elements, high correlations between Fe and Pb (0.929) and also Zn and Hg (0.980) were detected. Heavy elements in very low concentrations (3.1 and 2501 ppb for Cu and Sr, respectively and less than the detection limit for Pb, Zn, Fe, As, Sb, Hg and Se) were detected in the mine drainage due to Natural Alkaline Mine Drainage (NAMD) with pH=7.6. Mining, however, caused an elevation in the concentration of S, Sr, Cu, As and Se (430000, 8505, 3.7, 1.5 and 3 ppb, respectively) in the groundwater. S, with a rise of 9.4 times in the downstream groundwater comparing to the upstream groundwater, showed the highest increase.

Entrainment of heavy metals into food chain is of main environmental problems. A big part of crude oil is exported to Western Europe and Japan through Strait of Hurmoz, thus this strait plays a strategic role in the world economy. This research dealt with some sedimentological characteristics and pollution degree of superficial sediment by As and Hg in Sirik and Jask ports, east of Strait of Hurmoz. Sediment samples were taken from 16 stations in Sirik and Jask harbors from depths of 5 and 10 m in January 2009. Sedimentological studies showed that the sediments in terms of size are very fine and close to clay particles. Average content of organic matter and calcium carbonate were 8.25 and 13.17 percent respectively. The pH varied from 8.6 to 9.2. The ICP-MS analysis showed that the average concentrations of As and Hg in Sirik were 5.28 and 0.027 ppm and were 4.52 and 0.038 in Jask respectively. Average values of enrichment factor for As and Hg were calculated as 16.77 and 1.93 in Sirik and, 11.36 and 2.14 in Jask respectively. These values indicate high and low enrichment for the measured elements as well as their non-crustal sources (agricultural and industrial wastewater and oil pollutions) in the sediments of the region. Neighboring agricultural land around Sirik and the oil spill event on 23 May, 2006 in Jask Harbor area justify the higher average pollution factor of As in Sirik (0.4) than in Jask (0.34). Comparison of Hg pollution degrees in Sirik and Jask stations (0.46 and 0.43 respectively) shows more contamination of sediments by As and Hg in Sirik stations.