A. Mahvi | Tehran University of Medical Sciences (original) (raw)
Papers by A. Mahvi
Surfactant-modified clinoptilolite-rich tuff was used for the removal of methyl tert-butyl ether ... more Surfactant-modified clinoptilolite-rich tuff was used for the removal of methyl tert-butyl ether (MTBE) from aqueous solutions. Clinoptilolite zeolite from Miyaneh region of Iran was treated with sodium chloride and then modified with hexadecyltrimethylammonium chloride (HDTMA-Cl) and n-Cetylpyridinium bromide (CPB) to be used in different experimental conditions. The ability of raw or Non-Modified Zeolite (NMZ) and Surfactant-Modified Zeolites (SMZ) to remove MTBE from aqueous solutions was investigated as a function of contact time, pH and concentrations of adsorbent and adsorbate, by using a batch technique in aqueous system. The removal of MTBE from aqueous solutions by modified zeolites seemed to be more effective than non-modified samples. Also, HDTMA-modified zeolite had more effective performance than CPB-modified zeolite. The adsorption efficiency of MTBE onto SMZ S was found to increase by contact time and adsorbent concentrations, and by decreasing of pH and adsorbate concentrations. Empirical adsorption models of Langmuir and Freundlich were applied for the experimental data. Results showed that Langmuir isotherm was more suitable for this process. The experimental data fitted very well with the pseudo-second-order kinetic model. It was overally found that Surfactant-Modified Zeolites is an effective adsorbent for removal of methyl tert-butyl ether from contaminated solutions.
ABSTRACT Adsorption of methyl tert-butyl ether (MTBE) from aqueous solutions by granulated modifi... more ABSTRACT Adsorption of methyl tert-butyl ether (MTBE) from aqueous solutions by granulated modified nanozeolites Y was investigated. Nanozeolite Y powders were converted into granulated zeolites and subsequently modified with two cationic surfactants (20 mmol/dm(3)), to be used as adsorbent. Granulated nanozeolites were characterized by BET surface area analysis, elemental analysis and X-ray diffractometer. Hexadecyltrimethylammonium (HDTMA-Cl) modified granulated zeolite had more effective performance than N-cetylpyridinium bromide (CPB) modified granulated zeolite. The most conventional adsorption isotherms and kinetic models were applied to describe MTBE adsorption and reaction dynamic, respectively. The equilibrium sorption data fitted the Langmuir 2 isotherm model and the kinetic study was followed the pseudo-second-order model. The maximum adsorption capacities for HDTMA-Cl modified zeolite and CPB modified granulated zeolite were 333.33 and 142.8 mg/g, respectively as calculated by the Langmuir model. This study demonstrated that the removal of mtbe by granulated modified nanozeolites Y is a promising technique.
International Journal of Environmental Science & Technology, 2006
Jar-test experiments were conducted to study enhanced coagulation effectiveness in removal of dis... more Jar-test experiments were conducted to study enhanced coagulation effectiveness in removal of disinfection by products (DBPs) from Zayandehrud River at Isfahan Province-the center part of Iran-in 2004. In this study, the removal of suspended and colloidal particles and natural organic matter (NOM) at various coagulant doses and coagulation pHs was assessed through raw and treated water measurements of turbidity, UV 254 absorbance, TOC, and dissolved organic carbon (DOC). The trihalomethane formation potential (THMFP) was also determined by a mathematical relationship with TOC. Results indicated that NOM removal was a function of coagulant type, coagulant dose, and pH of coagulation. In general, TOC, DOC, and UV 254 absorbance removal enhanced with increasing coagulant dose. However, further increases in coagulant dosage had little effect on disinfection by-products precursors removal. Ferric chloride was consistently more effective than alum in removing NOM. Coagulation pH was appeared to be a determining factor for maximum NOM removal and the removal of DBPs precursors by enhanced coagulation was significantly enhanced at pH 5.5 in comparison with initial pH of water. Furthermore, it is specified that preadjustment of pH with sulfuric acid reduced the coagulant dosage and thus, production of sludge. The reduction in THMFP was consistent with the trends observed for DBPs precursors removal data (i.e. UV 254 and TOC data).
Iranian Journal of …, 2004
... 4, pp.41-50 43 Study of Cadmium Removal from Environmental Water by Biofilm Covered Granular ... more ... 4, pp.41-50 43 Study of Cadmium Removal from Environmental Water by Biofilm Covered Granular Activated Carbon *RA Dianati-Tilaki 1, AH Mahvi 2, M Shariat2, S Nasseri 2 1 Dept. ... Wat Res, 21(9): 1031-44. 16. Budinova TK, Petrov NV, Minkova VN, Gergova KM (1994). ...
Iranian Journal of Environmental Health Science & Engineering, 2008
The membrane bioreactor technology has been proven to be a single step process in efficient treat... more The membrane bioreactor technology has been proven to be a single step process in efficient treatment ofwastewater, either directly or after pretreatment by reverse osmosis. In this study, a pilot scale experimentwas studied to treat a synthetic municipal wastewater sample. The aerobic reactor with a submergedmembrane used in this work was continuously aerated for organic matter oxidation, nitrification andphosphorous uptake as well as for fouling control. The mixed liquor was recycled from the aerated zoneto the ...
Surfactant-modified clinoptilolite-rich tuff was used for the removal of methyl tert-butyl ether ... more Surfactant-modified clinoptilolite-rich tuff was used for the removal of methyl tert-butyl ether (MTBE) from aqueous solutions. Clinoptilolite zeolite from Miyaneh region of Iran was treated with sodium chloride and then modified with hexadecyltrimethylammonium chloride (HDTMA-Cl) and n-Cetylpyridinium bromide (CPB) to be used in different experimental conditions. The ability of raw or Non-Modified Zeolite (NMZ) and Surfactant-Modified Zeolites (SMZ) to remove MTBE from aqueous solutions was investigated as a function of contact time, pH and concentrations of adsorbent and adsorbate, by using a batch technique in aqueous system. The removal of MTBE from aqueous solutions by modified zeolites seemed to be more effective than non-modified samples. Also, HDTMA-modified zeolite had more effective performance than CPB-modified zeolite. The adsorption efficiency of MTBE onto SMZ S was found to increase by contact time and adsorbent concentrations, and by decreasing of pH and adsorbate concentrations. Empirical adsorption models of Langmuir and Freundlich were applied for the experimental data. Results showed that Langmuir isotherm was more suitable for this process. The experimental data fitted very well with the pseudo-second-order kinetic model. It was overally found that Surfactant-Modified Zeolites is an effective adsorbent for removal of methyl tert-butyl ether from contaminated solutions.
ABSTRACT Adsorption of methyl tert-butyl ether (MTBE) from aqueous solutions by granulated modifi... more ABSTRACT Adsorption of methyl tert-butyl ether (MTBE) from aqueous solutions by granulated modified nanozeolites Y was investigated. Nanozeolite Y powders were converted into granulated zeolites and subsequently modified with two cationic surfactants (20 mmol/dm(3)), to be used as adsorbent. Granulated nanozeolites were characterized by BET surface area analysis, elemental analysis and X-ray diffractometer. Hexadecyltrimethylammonium (HDTMA-Cl) modified granulated zeolite had more effective performance than N-cetylpyridinium bromide (CPB) modified granulated zeolite. The most conventional adsorption isotherms and kinetic models were applied to describe MTBE adsorption and reaction dynamic, respectively. The equilibrium sorption data fitted the Langmuir 2 isotherm model and the kinetic study was followed the pseudo-second-order model. The maximum adsorption capacities for HDTMA-Cl modified zeolite and CPB modified granulated zeolite were 333.33 and 142.8 mg/g, respectively as calculated by the Langmuir model. This study demonstrated that the removal of mtbe by granulated modified nanozeolites Y is a promising technique.
International Journal of Environmental Science & Technology, 2006
Jar-test experiments were conducted to study enhanced coagulation effectiveness in removal of dis... more Jar-test experiments were conducted to study enhanced coagulation effectiveness in removal of disinfection by products (DBPs) from Zayandehrud River at Isfahan Province-the center part of Iran-in 2004. In this study, the removal of suspended and colloidal particles and natural organic matter (NOM) at various coagulant doses and coagulation pHs was assessed through raw and treated water measurements of turbidity, UV 254 absorbance, TOC, and dissolved organic carbon (DOC). The trihalomethane formation potential (THMFP) was also determined by a mathematical relationship with TOC. Results indicated that NOM removal was a function of coagulant type, coagulant dose, and pH of coagulation. In general, TOC, DOC, and UV 254 absorbance removal enhanced with increasing coagulant dose. However, further increases in coagulant dosage had little effect on disinfection by-products precursors removal. Ferric chloride was consistently more effective than alum in removing NOM. Coagulation pH was appeared to be a determining factor for maximum NOM removal and the removal of DBPs precursors by enhanced coagulation was significantly enhanced at pH 5.5 in comparison with initial pH of water. Furthermore, it is specified that preadjustment of pH with sulfuric acid reduced the coagulant dosage and thus, production of sludge. The reduction in THMFP was consistent with the trends observed for DBPs precursors removal data (i.e. UV 254 and TOC data).
Iranian Journal of …, 2004
... 4, pp.41-50 43 Study of Cadmium Removal from Environmental Water by Biofilm Covered Granular ... more ... 4, pp.41-50 43 Study of Cadmium Removal from Environmental Water by Biofilm Covered Granular Activated Carbon *RA Dianati-Tilaki 1, AH Mahvi 2, M Shariat2, S Nasseri 2 1 Dept. ... Wat Res, 21(9): 1031-44. 16. Budinova TK, Petrov NV, Minkova VN, Gergova KM (1994). ...
Iranian Journal of Environmental Health Science & Engineering, 2008
The membrane bioreactor technology has been proven to be a single step process in efficient treat... more The membrane bioreactor technology has been proven to be a single step process in efficient treatment ofwastewater, either directly or after pretreatment by reverse osmosis. In this study, a pilot scale experimentwas studied to treat a synthetic municipal wastewater sample. The aerobic reactor with a submergedmembrane used in this work was continuously aerated for organic matter oxidation, nitrification andphosphorous uptake as well as for fouling control. The mixed liquor was recycled from the aerated zoneto the ...