Amir Hossein Baghaie; Raheleh Mirzaee
Abstract
Remediation of soils polluted with heavy metals or petroleum hydrocarbons is one of the environmental problems. This research aimed to evaluate the effect of carbon nanotubes, zeolite and AMF on triticale Ni concentration in a soil co-contaminated with diesel fuel and Ni. Treatments consisted of applying ...
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Remediation of soils polluted with heavy metals or petroleum hydrocarbons is one of the environmental problems. This research aimed to evaluate the effect of carbon nanotubes, zeolite and AMF on triticale Ni concentration in a soil co-contaminated with diesel fuel and Ni. Treatments consisted of applying multi walled carbon nanotubes (MWCNs) and zeolite at the rates of 0 , 1 and 2 % (W/W) in a Ni-polluted soil (0, 75 and 150 mg Ni/kg soil) which was naturally polluted with diesel fuel under cultivation of triticale plant inoculated with AMF. After 70 days, plants were harvested and soil and plant Ni concentration was measured using atomic absorption spectroscopy (AAS). Soil microbial respiration and degradation of diesel fuel were also measured. Applying 2 % (W/W) zeolite and MWCNs significantly increased the diesel fuel degradation in soil by 12.3% and 14.5 %, respectively, while the plant Ni concentration was decreased by 8.9 % and 13.1%, respectively. Increasing soil pollution with Ni from 0 to 75 mg/kg soil significantly decreased the degradation of diesel fuel in the soil under cultivation of plant inoculated with AMF by 14.4%. In addition, the soil microbial respiration was also decreased by 11.8%. The results of this study showed that application of zeolite and MWCNs had significant effect on increasing diesel fuel degradation in heavy metal polluted soil that is a positive point in environmental studies.
Ali Akbar Safari Sinegani; Omid Noroozi
Abstract
Survival of enteropathogenic bacteria in soil is a key factor to control waterborne diseases. The significance of zeolite nanoparticles in comparison with natural size particles on the survival of Escherichia coli in soil was studied in sterile and unsterile conditions. The experimental mixtures prepared ...
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Survival of enteropathogenic bacteria in soil is a key factor to control waterborne diseases. The significance of zeolite nanoparticles in comparison with natural size particles on the survival of Escherichia coli in soil was studied in sterile and unsterile conditions. The experimental mixtures prepared by adding zeolite and nanozeolite at levels of 0, 5, 15% w/w to a loam textural soil to obtain 100 gr mixtures. Mixtures inoculated by a nalidixic acid resistance Escherichia coli (E.coli NAR) at a rate of 106 cells gr-1 soil. Results showed that in the unsterile soils, adding 5% zeolite had no significant effect on the survival of bacteria in soil and 15% nanozeolite reduced bacteria survival in soil especially at initial days of inoculation (about 3 log-unit). While adding 15% zeolite and 5% nanozeolite had a significantly positive effect on bacteria's time need to reach the detection limit (td). Sterilization of soil mixtures significantly enhanced bacteria survival in all treatments. The highest value of td obtained in sterile soil amended with 15% zeolite (46 days). In sterile mixtures adding nanozeolite caused an increasing in bacteria population at initial days after inoculation (about 1-1.5 log-units). Decreasing in the size of natural zeolite particles to nanoscale had a negative effect on survival of the studied bacterium in unsterile mixtures and E.coli NAR survived more in zeolite amended mixtures. While this negative effect was not observed in sterile soil. These results clearly showed that competition is the main factor that controls enteropathogenic bacteria's survival in soil.
Taher Yousefi; Mohammad Abas Mohsen; Hamid Reza Mahmudian; Meisam Torab-Mostaeidi; Mohammad Ali Moosavian; Hassan Aghayan
Abstract
In the current work, the natural zeolite was modified with cobalt hexacyanoferrate and employed for adsorbent of Pb(II) ions from aqueous solution. The modification was approved by XRD and FTIR techniques. The Pb(II) adsorption capacity enhanced by 1.8 times from 60 mg/g (natural zeolite) to 100 mg/g ...
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In the current work, the natural zeolite was modified with cobalt hexacyanoferrate and employed for adsorbent of Pb(II) ions from aqueous solution. The modification was approved by XRD and FTIR techniques. The Pb(II) adsorption capacity enhanced by 1.8 times from 60 mg/g (natural zeolite) to 100 mg/g (modified zeolite) at optimal conditions. Factors such as time, pH, temperature, adsorbent dosage and initial concentration were investigated to optimize the adsorption condition. A fast sorption was observed in the initial contact time and equilibrium was achieved in less than 120 min. The optimum pH for lead removal was between 3 and 6. The adsorption capacity was increased and reached the maximum of 90 % at 2 g/L adsorbent dosage. Also, the adsorption increased as the concentration increased up to 500 mg/L and the sorption became constant at higher concentration. It was found that the double-exponential model describes the lead sorption kinetics and the Langmuir–model describe the isotherms.
Taher Yousefi; Hamid Raza Moazami; Hamid Reza Mahmudian; Meisam Torab-Mostaedi; Mohammad Ali Moosavian
Abstract
In the current research work the Iranian natural zeolite (clinoptililite) was modified with Cobalt Hexacyanoferrate nanopatricles. The natural and Cobalt Hexacyanoferrat modifed zeolites were characterized by FTIR and SEM techniques and were empolyed as an adsorbent for removal Cd(II) ions from ...
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In the current research work the Iranian natural zeolite (clinoptililite) was modified with Cobalt Hexacyanoferrate nanopatricles. The natural and Cobalt Hexacyanoferrat modifed zeolites were characterized by FTIR and SEM techniques and were empolyed as an adsorbent for removal Cd(II) ions from aqueous sloution. The adsorption expriments were performed in bach mode. The Cd(II) sorption capacity of Cobalt Hexacyanoferrat modified zeolite was 51 mg g-1. The effect of influceing factors such as time, temperature and initial concentration were investigated. A fast sorption was observed in the initial contact time and equilibrium was achieved in less than 100 min. The equilibrium adsorption data for Cd (II) were better fitted to the Longmuir adsorption isotherm model. The increase in temperature has a slight positive effect on the uptake of Cd(II) ions. The results indicated that the Cobalt Hexacyanoferrate nanopatricles modified natural zeolite has effective potential for the adsorption of Cd(II) from the wastewater.
Mansoor Kazemimoghadam
Abstract
Zeolite membranes have uniform and nano-sized pores, and they separate molecules based on differences in the molecules size and diffusion properties. Different routes used to prepare zeolite composite membranes include growing zeolite layers from gels on porous supports. Our approach to membrane synthesis ...
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Zeolite membranes have uniform and nano-sized pores, and they separate molecules based on differences in the molecules size and diffusion properties. Different routes used to prepare zeolite composite membranes include growing zeolite layers from gels on porous supports. Our approach to membrane synthesis was based on hydrothermally converting films of layered aluminosilicates into zeolite films. In this research, synthesis of nano NaA zeolite membrane from kaolin was investigated. In the first step, kaolin has been calcined at 700 °C to the metakaolinite phase. As a second step, the zeolitisation experiments have been carried out under hydrothermal conditions. The metakaolinite obtained has been reacted with NaOH solutions in autoclaves at 100°C. X-ray diffraction (XRD) patterns of the membranes exhibited peaks corresponding to the support and the zeolite. The morphology of the support and membrane subjected to crystallization was characterized by Scanning electron microscopy (SEM). Separation performance of the NaA membranes was evaluated using pervaporation of water–Ethanol mixtures. The membranes showed high water selectivity in the water–Ethanol mixtures.