4 research outputs found
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Removal of sulfur dioxide by carbon impregnated with triethylenediamine, using indigenously developed pilot scale setup
In order to provide protection against extremely toxic gases, activated carbon (AC) adsorption has long been regarded to be a useful technology in terms of gas removal. AC without chemical impregnation has been considerably less effective than impregnated ACs. AC in present use was modified with an organic amine, i.e., triethylenediamine (TEDA) to enhance the physical and chemical properties of AC in order to remove specific poisonous gases. With the rising concern on environmental pollution, there has been an increased curiosity in ACs as the means for eliminating pollutants from environment. Purpose of this study was to assess the TEDA impregnated AC in terms of adsorption capability for simulant gas like SO
. Analysis was done in a properly designed setup. By using the scheme reported here, significant adsorption of toxic gas was obtained. Maximum removal capability observed by AC-4 for SO
gas was 374 mg/g-C and its breakthrough time was 264 min. Breakthrough time and adsorption capacity of AC-4 was found to be 25 times and 10 times greater as compared to raw AC. Different characterization techniques were also used to study impregnated AC. It was found that chemical adsorption was the crucial means by which TEDA-impregnated AC removed the simulant gas. Langmuir model was best to represent equilibrium, and adsorption kinetics follow second-order model. The process was endothermic, favorable, and spontaneous
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Impregnation on activated carbon for removal of chemical warfare agents (CWAs) and radioactive content
Nuclear, biological, and chemical warfare (NBC) agents cause an inevitable threat to defense forces and civilians. Exposure to these toxic agents causes a lot of damage to lives. One can avoid the damage of these toxic agents by taking appropriate preventive measures. Respiratory protection is obviously necessary when military personnel or civilians get bounded by such type of noxious situation as contaminant-free air is then required for breathing and it can only be provided by means of a proper gas mask and relevant canister. In purification of contaminated atmospheres, activated carbon has so far met with outstanding success. It removes toxic chemicals either by chemical or physical adsorption from the contaminated air. When any toxic chemicals get adsorbed on the modified impregnated carbon's surface, they usually adsorb there by means of chemical reactions. Destruction of adsorbed toxic substances is expected by such a reactive carbon. In this perspective, an attempt has been made to review the literature from past decades on the removal of toxic chemical warfare agents (CWAs) and radioactive content from air stream in case of any nuclear, biological, and chemical attack by selectively modifying or impregnating the activated carbon surface. This review also covers some important adsorption properties of materials being used in gas mask filters for effective removal of chemicals from airstream. The probable removal mechanisms of various chemical warfare agents and radioactive content have also been reviewed
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Synthesis and adsorption behavior of activated carbon impregnated with ASZM-TEDA for purification of contaminated air
In current study, ASZM-TEDA carbon (Carbon impregnated with Copper, Silver, Zinc, Molybdenum and Triethylenediamine) was successfully prepared with non-ammonium water soluble salts using incipient wetness method and TEDA was impregnated on raw activated carbon (RAC) by sublimation process. Aim of this study was to access the adsorption capability of RAC and ASZM-TEDA carbon for SO2 and NO2 gases. For characterization of material, XRD, SEM, EDX spectroscopy, EDX mapping, TGA, BET surface area analyzer and Boehm titrations were used. Results indicate that ASZM-TEDA carbon, prepared with non-ammonium salts, provided satisfactory protection against challenge gases. Using the FTIR based gas analyzer, a significant increase in breakthrough time of ASZM-TEDA carbon was observed i.e. 29.0% for SO2 and 18.7% for NO2 gases as compared to RAC and breakthrough time was 210 and 197 min, respectively. Adsorption capability of ASZM-TEDA carbon was found to be 390 mg NO2/g-C and 448 mg SO2/g-C. In comparison with RAC, ASZM-TEDA carbon showed enhanced adsorption capability up to 31.5% for NO2 and 55.9% for SO2.
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•Non-ammonia water soluble salts were used for impregnation.•Metal oxides were impregnated on activated carbon by imbibing limit method.•Triethylenediamine was impregnated on metal impregnated activated carbon surface by sublimation process.•Prepared IACs were found promising and efficient for removal of SO2 and NO2 gases from air.•ASZM-TEDA carbon showed significant decontamination capability for SO2 and NO2 gases
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Investigation of Cu/Zn/Ag/Mo-based impregnated activated carbon for the removal of toxic gases, synthesized in aqueous media
Impregnated activated carbons (IACs) have been prepared successfully from aqueous solution of copper, zinc, silver and molybdenum for the removal of toxic gases from air. First, the activated carbon was impregnated by imbibing limit method with single metal, then a combination of 2 to 4 metals was used. The aim of this study was to access the adsorption capability of raw activated carbons (RAC) and IACs for SO2 and NO2 gases. Different techniques such as XRD, TEM, SEM, EDX mapping, AAS and BET surface area analyzer were used for characterization of materials. Results indicate that IACs provided satisfactory protection against challenge gases. Using the FTIR based gas analyzer, a significant increase in breakthrough time of all IACs was observed as compared to RAC. The maximum breakthrough time was achieved with four metals (Cu, Zn, Ag and Mo) impregnated on activated carbon i.e. 120.5 min for SO2 and 139.0 min for NO2, which were 13 and 25 times high respectively, in comparison with RAC. Adsorption capacity was found to be 320 mg SO2/g-C and 380 mg NO2/g-C. In comparison with RAC, ASZM2 carbon showed enhanced adsorption capability up to 30 times for SO2 and 40 times for NO2.
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•Water soluble salts were used for impregnation.•Metal oxides were impregnated on activated carbon by imbibing limit method.•Prepared IACs were found promising and efficient for removal of SO2 and NO2 gases from air.•ASZM2 carbon showed significant decontamination capability for SO2 and NO2 gases