hosien Shokripour; Mona Golabi; Hadi Moazed; Nematolah Jafarzade Haghighy Fard
Abstract
Introduction: In recent years, concern over the long-term effects of heavy metals has been increased as environmental pollutants. Environmental pollution of heavy metals is one of the major environmental issues. Unfortunately, due to the uncontrolled entry of various types of industrial waste, their ...
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Introduction: In recent years, concern over the long-term effects of heavy metals has been increased as environmental pollutants. Environmental pollution of heavy metals is one of the major environmental issues. Unfortunately, due to the uncontrolled entry of various types of industrial waste, their input is increasing into air, water and soil sharply. Heavy metals are irresolvable and tend to accumulate in the organs and tissues of living organisms that cause a variety of diseases and disorders for humans and other living organisms. Recently, biological methods and technologies such as biosorbent and bio-accumulation have been used to help researchers to confront the problem of removing heavy metals from sewage. In bio-accumulation technology is used living biota to remove metals. However, in the second method, or biological absorption is used of dead or inactive biologically is this purpose. The main objective of this research is to determine the capability of the storage of cadmium as heavy metal by modified Ceratophyllum demersum biomass. In addition, the effect of pH on adsorption rate, contact time on adsorption rate, adsorbent adsorption, initial concentration of adsorbant (cadmium) were evaluated on adsorption. Also, kinetic and isotherm models of absorption were determined.
Materials and Methods: In the present study, the effect of modification of Ceratophyllum demersum on the removal of Cadmium from aqueous solution was investigated. Ceratophyllum demersum or blue fork is a submerged plant that is commonly found in aqueous humorous streams containing moderate to high levels of nutrients. One of the suitable environments for growth of Ceratophyllum demersum is low depth and laminar flow of water channels. In this regard, a search was conducted on irrigation channels inside Shahid Chamran University of Ahvaz and large quantities of this plant were observed in many parts of these channels. The plant was collected from the entrance channel of the Karoon River to the university. After collecting the plant and washing it with urban water and distilled water and drying it in free air was dried at 70 ° C. After that the dry matter was milled and it passed through the standard No. 50 sieve. In this study, alkaline solutions (0.5M NaOH solution) were used to modify biomass. This method has been shown to be effective in similar studies, and has greatly increased the absorption capacity of adsorbents. Preparation of cadmium storage solution was performed based on the methods presented in the standard reference for water and wastewater testing.
Results and Discussion: The morphology characteristics of biosorbent surface by Scanning Electron Microscope (SEM) were studied and desirable effects of modification on characteristics of biosorbent surface were proved. The result of study showed that by increasing pH from 3 to 8, the removal efficiency increased from 93% to 97% at pH 7, and then decreased to 85% at pH 8. In addition, adsorption capacity, in similar way, increased from 7.04 to 7.35 and then decreased to 6.44 mg/g. Therefore, pH 7 was determined as optimum pH. Increasing contact time, from 5 to 240 minute, caused changes in removal efficiency from 67% to 98% after 180 minute, and then decreased slightly. Adsorption capacity, in similar way, increased from 6.25 to 9.13 mg/g and then decreased slightly and contact time of 60 minute was determined as equilibrium time. Increasing dose of biosorbent from 0.02 to 4 g/L, causing increase of removal efficiency from 37% to 99% and decrease of adsorption capacity from 169.5 to 2.35 mg/g and finally dose of 10 mg/L was determined as proper dose of biosobent. Increasing of initial concentration of Cadmium solution from 10 to 200 mg/L led to decrease in removal efficiency from 96% to 31%, and increase in adsorption capacity from 9.18 to 59.7 mg/g, and concentration of 10 mg/L was determined as optimum initial concentration of Cadmium. Finally, kinetic and isotherm adsorption models were studied. In kinetic models, pseudo-second order kinetic model, with correlation coefficient of 0.99 described biosorption better than pseudo-first order. In isotherm models, the Langmuir isotherm with correlation coefficient of 0.99 described biosorption process such better than other models. Based on results obtained in this study, the high capability of modified Ceratophyllum demersum, as a favorable biosorbent for cadmium removal from aqueous solution was proved.
Conclusions: The images from the SEM device showed that adsorption modification increased the absorption capacity to absorb cadmium ions. The highest efficiency was achieved in pH equal to seven. According to the economic considerations and optimum consumption of the energy 60 minutes was determined as the time of equilibrium. Kinetic modeling shows that Pseudo second order has the best matching with experimental data.
R. Lalehzari; Saeid Boroomand Nasab; Hadi Moazed; A. Haghighi
Abstract
Introduction: Groundwater is the largest resource of water supplement and shortages of surface water supplies in drought conditions that requires an increase in groundwater discharge. Groundwater flow dependson the subsurface properties such as hydraulic gradient (water table gradient or head loss in ...
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Introduction: Groundwater is the largest resource of water supplement and shortages of surface water supplies in drought conditions that requires an increase in groundwater discharge. Groundwater flow dependson the subsurface properties such as hydraulic gradient (water table gradient or head loss in artesian condition) and hydrodynamic coefficients. The flow treatment is analyzed with an accurate estimation of effective parameters in groundwater equation. This function is obtained using the continuous equation. Inlet and outlet flows of a cell are equal to storage amounts in the continuous equation. Analytical solution of this equation is complex, so numerical methods are developed including finite element and finite difference methods. For example, Feflow is a groundwater modeling tool that makesuse of finite element method (Reynolds and Marimuthu, 2007). Modflow as a finite difference three-dimensional model simulated underground flow under steady and unsteady conditions in anisotropic and non-homogeneous porous media. Modflow is designed to simulate aquifer systems in which saturated-flow conditions exist, Darcy’s Law applies, the density of groundwater is constant, and the principal directions of horizontal hydraulic conductivity or transmissivity do not vary within the system. In Modflow, an aquifer system is replaced by a discretized domain consisting of an array of nodes and the associated finite difference blocks. Groundwater modeling and water table prediction by this model have the acceptable results, because many different informations of water resource system are applied. Many people and organizations have contributed to the development of an effective groundwater monitoring system, as well as experimental and modeling studies (Lalehzari et al., 2013). The objective of this paper is investigation of hydraulic and physical conditions. So, a numerical model has to be developed by PMWIN software for Bagh-i Malek aquifer to calculate hydrodynamic coefficients and predict water table in the future.
Materials and Methods: Bagh-i Malek aquifer located in Khuzestan province is mainly recharged by inflow at the boundaries, precipitation, local rivers and return flows from domestic, industrial and agricultural sectors. The discharge from the aquifer is through water extraction from wells, springs, and qanats as well as groundwater outflow and evapotranspiration. In this study, conceptual model of Bagh-i Malek aquifer on the framework of finite difference numerical approach has been used in simulating groundwater flow treatment. Water table data of 8 piezometers was collected for the 10 year duration from 2002 to 2012. The study years are divided into 40 seasonal stress periods with daily time step. Hydraulic conductivity, specific yield and recharge were calibrated in these periods. Verification was made between the simulated and measured hydraulic heads in the next calibration year. To simulate the groundwater table elevation in this study area, the PMWIN model is used. Bagh-i Malek aquifer is considered as a single layered aquifer, and therefore only the horizontal hydraulic conductivity is estimated. Modflow was used to simulate both steady state and transient flow systems. In steady conditions it is assumed that the total of time simulation is a time period and it does not change inlet data in the modeling duration. In unsteady conditions,the duration of study is divided into some stress periods that data is changed in every period.
Results and Discussion: Estimation of hydraulic conductivity is the first step of calibration process at steady state conditions. The correct assignment of hydraulic conductivity has a main effect on other parameters accuracy. Hydraulic conductivity mapping indicated that the maximum values are in the Eastern North (6-7 m/day) of the aquifer. The twice calibrated parameter is specific yield in unsteady conditions. Specific yield mapping indicated that the values vary from 0.03 to 0.08 and are maximum in the Southern regions of the plain similar to hydraulic conductivity. The results confirm that the flow model has the tolerable simulation accuracy by variances of 3.1 and 3.84 in calibration and verification processes, respectively. The sensitivity of the flow model to decreasing the hydraulic conductivity is more than increasing it. 50 percentage declined into the hydraulic conductivity causes the increase of the variance from 3.1 of initial value to 44.
Conclusions: Mapping of calibrated hydraulic conductivity showed that the Eastern North of aquifer has the higher transmissivity and discharge capability in comparison to Southern parts. At last, the result show that the Bagh-i Malek aquifer model is sensitive to recharge, hydraulic conductivity and specific yield, respectively.
A. Sadeghilari; Hadi Moazed; AbdAli Naseri; A. Mahjobi; A.M. Liaghat
Abstract
In arid and semiarid regions, controlled drainage is the next logical step towards improving water management in irrigated agriculture and reducing the environmental impacts of subsurface drainage flow. Controlled drainage has been practiced in humid areas for a long time. In this research a controlled ...
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In arid and semiarid regions, controlled drainage is the next logical step towards improving water management in irrigated agriculture and reducing the environmental impacts of subsurface drainage flow. Controlled drainage has been practiced in humid areas for a long time. In this research a controlled drainage system in Khuzestan Province, Southwest Iran was tested as a strategy for continuous water table management with the benefits of optimizing water use and reducing unnecessary drainage and nitrogen losses from agricultural fields. To study the feasibility and performance of water table management, Field experiments were carried out on a 63.41 ha with 3 treatments on the farms under subsurface drainage of Imam Khomeini's sugarcane agro-industry. 3 treatments compared consisted of a free drainage treatment (FD) and tow controlled drainage treatment with water table controls set at 90 centimeter (CD90) and 70 centimeter (CD70) below the soil surface. Collected data during a sugarcane growing season included water table depth, drained volume, nitrate-nitrogen and ammonium-nitrogen concentration in the drainage water and groundwater. Controlled drainage had a significant hydrological and environmental effect during studding period. Compared with CD, the total drain outflow from CD70 and CD90 area were 62.48 and 48.98% less, respectively. Compared with CD, the total amounts of nitrate-nitrogen and ammonium-nitrogen in drain outflow were about 45 to 60 % and 50 to 65 % less, respectively. Nitrate-nitrogen and ammonium-nitrogen concentration in the both of drainage water and groundwater did not differ significantly in all of the treatment. These data suggest that controlled drainage can be applied at big scale in the Khuzestan Province with the most installed subsurface drainage in Iran, with advantages for water conservation and environment.
I. Nikravesh; Hadi Moazed; S. Broomandnasab; AbdAli Naseri
Abstract
Many of irrigated agriculture problems are resulting from chemical and physical composition of irrigation water. The irrigation water quality is effective on soil moisture characteristic curve by effect on soil structure, pore size distribution and continuity of them. The aim of this study was to evaluate ...
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Many of irrigated agriculture problems are resulting from chemical and physical composition of irrigation water. The irrigation water quality is effective on soil moisture characteristic curve by effect on soil structure, pore size distribution and continuity of them. The aim of this study was to evaluate the effect of different water salinity in the presence of constant turbidity on the soil moisture curve. The salinity treatments at five levels (1, 2, 4, 6 and 8 dS/m) with constant turbidity (200 NTU) were applied. These treatments were investigated at three depths of soil (0 to 15, 15 to 30 and 30 to 45 cm) with a silt-loam texture with three replications in a randomized complete block design. Soil water retention curve was determined by using pressure plate method. The results were statistically analyzed with MSTATC software. The results showed that the water percent of the soil of S2, S3, S4, S5 treatments of irrigation water quality increased to values 13.65, 20.20, 23 and 30 percent compared to S1 treatment. Comparison of water percent of soil at various depths showed that the depth of the second and third compared to the first decreased to 1.40 and 2 percent.
