Showing 4 results for Hamidpour
M. Hamidpour, A. Jalalian, M. Afyuni, B. Ghorbani,
Volume 16, Issue 62 (Winte - 2013 2013)
Abstract
Models are helpful tools to predict runoff, sediment and soil erosion in watershed conservation practices. The objectives of this research were to investigate sensitivity analysis, calibration and validation of EUROSEM model in estimation of runoff in Tangh-e-Ravagh sub-basin of Karoun watershed. The model was tested in a one hectare experimental test site. The area was divided into nine elements according to EUROSEM user's manual. A triangular weir was installed at the outlet of the area to collect runoff in specified time periods for six rainfall events. Sensitivity analysis of the model was performed by a ±10% change in the dynamic parameters of the model and examining the outputs for a rainstorm. Sensitivity analysis showed that total runoff was sensitive to saturated hydraulic conductivity and insensitive to soil cohesion. Sensitivity analysis indicated that the model sensitivity depends on evaluation conditions and it is site-specific in nature. Calibration and validation of the model was performed on input parameters. Calibration of hydrographs was performed by decreasing saturated hydraulic conductivity and capillary drive and increasing initial soil moisture. Validation results showed that EUROSEM model simulated well the total runoff and peak of runoff discharge, but it could not simulate well the time of runoff, time to peak discharge
S. Farahi, M. Hamidpour, H. Shirani, H. Dashti, M. Heshmati,
Volume 17, Issue 66 (winter 2014)
Abstract
This research was conducted to study the effect of natural and polyacrylamide-modified montmorillonite on the sorption of Cd from aqueous solutions. The sorption of Cd on the sorbents was studied as a function of pH (Cd concentration: 10 mg L-1) in the range of 4-8.5, and as a function of metal concentration (Cd concentration in the range of 1-10 mgL-1) using a 24h batch equilibration. Experimental and modeling data from equilibrium investigations revealed that the Koble–Corrigan sorption model describes the interaction between Cd and the two sorbents better than the Freundlich and Langmuir models. The values of KF constant of Freundlich and KL constant of Langmuir models were higher for sorption of Cd onto the modified montmorillonite than for those of natural montmorillonite. Maximum sorption capacity calculated from the Langmuir model was 0.6 and 0.7 mg g-1 for natural and modified montmorillonite, respectively. These values are indications of high sorption affinity of Cd to montmorillonite in the presence of polyacrylamide. The amount of Cd sorbed by modified montmorillonite decreased by increasing solution pH while Cd sorption by natural montmorillonite increased by increasing the solution pH.
S. Molaei, H. Shirani, M. Hamidpour, H. Shekofteh , A. A. Besalatpour,
Volume 19, Issue 74 (Winter 2016)
Abstract
This experiment was conducted to evaluate the effect of vermicompost, pistachio kernel and shrimp shell on the immobilization and availability of Cd, Pb and Zn in corn in polluted soils. Treatments consisted of two levels of pistachio kernel, shrimp shell and vermicompost (5 and 10 % w/w). In control treatment, no amendment was added to the soil. The experiment was carried out as a completely randomized design with 3 replications. Plants grew for two months in the greenhouse. Then, all the plants were harvested and their shoots and roots were separated, washed with distilled water and oven dried at 65 °C to a constant mass. The measured characteristics were dry weight of shoots and roots, leaf area, greenness index, chlorophyll fluorescence, maximal quantum yield of PS photochemistry (Fv/Fm), performance index (PI), and total concentrations of Cd , Pb and Zn in shoots and roots. Results showed that plant growth parameters (dry weight of shoots and roots, leaf area) and photosynthetic characteristics (chlorophyll fluorescence, Fv/Fm, and PI) were higher in plants grown in vermicompost and pistachio kernel treatments as compared to those grown in control. Plants died in shrimp shell treatment after two weeks. The concentration of Cd, Zn and Pb in shoots and roots of plants grown in vermicompost and pistachio kernel treatments were lower than those grown in control.
M. Karamooz, M. Hamidpour,
Volume 22, Issue 1 (Spring 2018)
Abstract
Siderophores are low molecular weight iron-binding ligands produced by aerobic soil microorganisms and some plants roots. They may also develop complexes with other metals such as Cd, thereby influencing the bio-availability, toxicity and mobility of Cd in the soils and aqueous environments. The main objective of this study was to investigate the effects of desferal siderophore (DFOB) on the adsorption of Cd on muscovite. The adsorption of Cd on muscovite was studied as a function of pH (Cd concentration: 5.0 mg L-1) in the range of 3.0-8.0, as a function of metal concentration (Cd concentration in the range of 1.5-10.0 mg L-1); this was done in the absence and presence of siderophore (DFOB concentration 250 μM) using a 24h batch equilibration experiment. The results of pH dependent experiments showed that the siderophore deceased the adsorption of Cd onto muscovite at pH ≥5. The results of the isotherms experiments also showed that the removal of Cd from solution was affected by siderophore in all equilibrium concentrations of Cd at both pHs. Siderophore decreased the adsorption of Cd by the mineral. The Freundlich and Langmuir isotherms described the equilibrium data satisfactorily. The values of Freundlich (KF) and Langmuir (KL) bonding constants were greater in the suspensions without siderophore, as compared to those containing siderophore, thereby indicating the low adsorption affinity of Cd on muscovite in the presence of the siderophore.
