Showing 3 results for M. Chorom
M. Chorom, C. Jafari,
Volume 7, Issue 2 (summer 2003)
Abstract
Environmental pollution is one of the major problems for humans and animals. Radioactive wastes and heavy metals are important sources of pollution. Recent studies suggest that soil and geomedia have a high potential for the disposal of radioactive wastes and heavy metals. The clay minerals in geomedia can act as a barrier against radioactive wastes and heavy metals. However, enough information and experimental evidence about the mechanisms involved in the fixation of metals by clays are not available. This study aimed to show the effect of clay type on the fixation of cobalt and cadmium as affected by thermal energy. Increasing the temperature from 25 to 400°C decreased the CEC of clays in Ahwaz and Darab soils saturated with cobalt from 35.6 and 50.1 cmolc+/kg to 28.8 and 4.5, respectively. In cadmium clays, however, reductions in CEC were minimal (from 34.3 and 51.2 at 25°C to 32.5 and 47.7 cmolc+/kg at 400°C, respectively) compared to cobalt saturated clays. Consequently, the bonding characteristics change according to the size of the cations upon thermal treatment. The small cation, cobalt with an ionic radius of 0.68 Å, apparently migrates to the octahedral vacant sites and forms covalent bonds after heating at 400°C to become non-exchangable (fixed). The larger cation, Cd with an ionic radius of 0.97Å, apparently does not migrate into lattice sites on thermal treatment and remains exchangeable.
V. Sarvi Moghanloo , M. Chorom, H. Motamedi , B. Alizadeh, Sh. Ostan,
Volume 15, Issue 56 (sumer 2011)
Abstract
Soil enzymes are the catalysts for important metabolic process functions including the decomposition of organic inputs and the detoxification of xenobiotics. The aim of this research was to determine the pattern of variation in the activities of dehydrogenase, urease, lipase and phosphatase enzymes, determining the number of hetrotrophic and degrading bacteria and measuring the soil respiration and yield plants during the bioremediation of oil contaminated soils. To this aim, the soil deliberately contaminated with crude oil at a 1 and 2 wt% rate and in four treatments including: plant multiflorum (T1), plant multiflorum with mycorrhiza inoculation (T2), plant multiflorum with oil degrading bacteria inoculation (T3), plant multiflorum with mycorrhiza and oil degrading bacteria inoculation (T4) was employed for bioremediation of oil contaminated soil. The above parameters were determined in five stages during bioremediation and ultimately for the yield of plants at the end of this period .The results showed that the activity of urease and hydrogenase anzymes were increased or decreased parallel to contaminant increase and decrease. In contrast, the activity of lipase anzyme was decreased with contaminant increase and increased with contaminant decrease. Therfore, it can be a good choice for monitoring of bioremediation of contaminated soils. The results showed that the number of degrading and hetrotrophic microorganisms were increased by increasing the amount of contamination and the number of degrading and heterotrophic bacteria were decreased parallel to contaminant decreasing especially in those samples treated with mycorrhiza inoculation. The plant yield and amount of degradation of oil compounds were highest in mycorrhiza plus degrading bacteria treatment.
A. Mohammadi, M. Chorom, N.hosseini Zare, H. Amerikhah, A. Ramazan Poor,
Volume 17, Issue 65 (fall 2013)
Abstract
The purpose of this study was to investigate cadmium adsorption through Freundlich and Langmuir equations in sediments of Karun River in three hydrometric stations (5th Ahvaz Bridge, Darkhovin and Khorramshahr) in the low-water and high-water seasons. Fitting of data from experiments on cadmium absorption to Freundlich and Langmuir equation showed they are compatible. According to the conducted experiments, there was a significant difference at 0.01 levels between b coefficient of Langmuir equation with the organic matter percentage and the clay content in both Low and high water seasons, while there was no significant difference between k coefficient of Langmuir equation with the organic matter percentage and the clay content for the two seasons. The results also suggested that there is a significant relationship between Kf of Freundlich equation with the organic matter percentage and clay content, at significant levels of 0.05 and 0.01 for the organic matter percentage and the clay content, respectively. Comparison of the means of low and high water seasons revealed that there is no significant relationship between Langmuir coefficients, whereas in Freundlich equation, a significant difference at 0.01 level was observed between kf coefficients. Generally, the obtained results indicated that cadmium adsorption by sediments in low-water season is higher than high-water season. Also, cadmium adsorption by the 5th Ahvaz Bridge sediments due to the sandy texture was less than those adsorbed by both Darkhovin and Khorramshahr sediments.
