This paper presents the preparation of carbon conditioned with iron nanoparticles (CI) using a pineapple peel treated with iron salts, carboxymethylcellulose sodium and hexamine. First, the pineapple peel was analyzed...This paper presents the preparation of carbon conditioned with iron nanoparticles (CI) using a pineapple peel treated with iron salts, carboxymethylcellulose sodium and hexamine. First, the pineapple peel was analyzed by thermo gravimetric analysis (TGA) to determine the optimal temperature for pyrolysis. The formation of carbon conditioned by iron nanoparticles was studied as a function of time at 30 min, 60 min, 90 min, 120 min, 150 min and 180 min. Scanning electron microscopy (SEM) was used to identify changes in the morphology of the materials. The specific area of each material was obtained by the BET method. The elemental composition of pineapple-peel (PP), washed pineapple-peel (WPP) and carbon iron (CI), was determined by neutron activation analysis (NAA). The results show that the optimal time for obtaining spherical iron nanoparticles with a diameter between 10 nm and 30 nm is 180 min on the carbonaceous material with a specific surface area of 167 m2/g.展开更多
The objective of this work is to study a comprehensive performance of three types of structured parking in CO2 absorption application. One of them was developed in Mexican National Institute of Nuclear Research （ININ...The objective of this work is to study a comprehensive performance of three types of structured parking in CO2 absorption application. One of them was developed in Mexican National Institute of Nuclear Research （ININ abbreviation in Spanish of Instituto Nacional de lnvestigaciones Nucleates）, and the other two, Sulzer BX and Mellapak 250Y, by Sulzer Brothers Ltd. Aqueous solution of 30 weight % Monoethanolamine was employed as absorption solvent. The performance of the structured packing was evaluated in terms of the pressure drop, holds up, volumetric overall mass transfer coefficient and height of a global transfer unit of gas and liquid side as a function of the process operating parameters including gas and liquid load, by using hydrodynamic and mass transfer models. The pressure drop of ININ packing was higher than Sulzer BX and Mellapak 250Y, and volumetric overall mass transfer coefficient values are similar of Sulzer BX values and higher than Mellapak 250Y, although Sulzer BX and ININI 8 packing had less height of a global transfer unit of gas side values than Mellapak 250Y packing. The above-mentioned are consequences of the geometric characteristics and operational behavior for each packing.展开更多
Households are the sources contributing the most to the production of urban solid wastes in developing countries. The present study analyses the generation of domestic solid wastes in a settlement in Mexico in two dif...Households are the sources contributing the most to the production of urban solid wastes in developing countries. The present study analyses the generation of domestic solid wastes in a settlement in Mexico in two different years. The goals were to compare composition and rates of generation into the periods to assess changes and the influence of socioeconomic variables. In 1998 and 2004, wastes from households were sampled of three socioeconomic levels randomly selected, and a survey was applied. Data obtained were analyzed with descriptive and multivariate analysis. Results of generation rate and composition of domestic solid wastes showed a negative correlation between generation and income in the first one, but positive in the second one;in both, composition did not show correlation. Rates of per capita generation, per household, population and density of inhabitants per dwelling increased, and the generation of wastes were more with respect to population growth, which emphasizes the influence of economic and demographic variables. This study corroborates that households are the principal sources of urban solid wastes and it is emphasized that management strategies must preponderate households to be successful. In addition, this information is important to establish strategies for an integral management of urban solid wastes in developing countries.展开更多
In the present investigation, two zeolite-rich tuffs from Guaymas and El Cajon（State of Sonora）, which were conditioned with a sodium chloride solution and subsequently modified with a thiourea solution, were chosen...In the present investigation, two zeolite-rich tuffs from Guaymas and El Cajon（State of Sonora）, which were conditioned with a sodium chloride solution and subsequently modified with a thiourea solution, were chosen to evaluate the removal of Cd from aqueous systems. The zeolitic materials were characterized by scanning electron microscopy and X-ray diffraction. The surface area was also determined. The experiments were performed in a batch system, and the influences of p H, contact time between phases, and the concentration of Cd in the solution on the adsorption by sodium or thiourea-modified zeolite-rich tuff were investigated. It was found that the efficiency of Cd ion removal from aqueous solutions is influenced by the p H of the aqueous systems. The Cd adsorption kinetic data were well fitted to a pseudo-second-order model in all cases. The Langmuir and Langmuir–Freundlich isotherms adequately described the Cd sorption behavior by the zeolite from El Cajon pretreated with Na Cl and the zeolite from Guaymas modified with thiourea, respectively.展开更多
文摘This paper presents the preparation of carbon conditioned with iron nanoparticles (CI) using a pineapple peel treated with iron salts, carboxymethylcellulose sodium and hexamine. First, the pineapple peel was analyzed by thermo gravimetric analysis (TGA) to determine the optimal temperature for pyrolysis. The formation of carbon conditioned by iron nanoparticles was studied as a function of time at 30 min, 60 min, 90 min, 120 min, 150 min and 180 min. Scanning electron microscopy (SEM) was used to identify changes in the morphology of the materials. The specific area of each material was obtained by the BET method. The elemental composition of pineapple-peel (PP), washed pineapple-peel (WPP) and carbon iron (CI), was determined by neutron activation analysis (NAA). The results show that the optimal time for obtaining spherical iron nanoparticles with a diameter between 10 nm and 30 nm is 180 min on the carbonaceous material with a specific surface area of 167 m2/g.
文摘The objective of this work is to study a comprehensive performance of three types of structured parking in CO2 absorption application. One of them was developed in Mexican National Institute of Nuclear Research （ININ abbreviation in Spanish of Instituto Nacional de lnvestigaciones Nucleates）, and the other two, Sulzer BX and Mellapak 250Y, by Sulzer Brothers Ltd. Aqueous solution of 30 weight % Monoethanolamine was employed as absorption solvent. The performance of the structured packing was evaluated in terms of the pressure drop, holds up, volumetric overall mass transfer coefficient and height of a global transfer unit of gas and liquid side as a function of the process operating parameters including gas and liquid load, by using hydrodynamic and mass transfer models. The pressure drop of ININ packing was higher than Sulzer BX and Mellapak 250Y, and volumetric overall mass transfer coefficient values are similar of Sulzer BX values and higher than Mellapak 250Y, although Sulzer BX and ININI 8 packing had less height of a global transfer unit of gas side values than Mellapak 250Y packing. The above-mentioned are consequences of the geometric characteristics and operational behavior for each packing.
基金funded by The Coordination of Scientific Research of the Universidad Michoacana de San Nicolas de Hidalgo through project number 5.9.
文摘Households are the sources contributing the most to the production of urban solid wastes in developing countries. The present study analyses the generation of domestic solid wastes in a settlement in Mexico in two different years. The goals were to compare composition and rates of generation into the periods to assess changes and the influence of socioeconomic variables. In 1998 and 2004, wastes from households were sampled of three socioeconomic levels randomly selected, and a survey was applied. Data obtained were analyzed with descriptive and multivariate analysis. Results of generation rate and composition of domestic solid wastes showed a negative correlation between generation and income in the first one, but positive in the second one;in both, composition did not show correlation. Rates of per capita generation, per household, population and density of inhabitants per dwelling increased, and the generation of wastes were more with respect to population growth, which emphasizes the influence of economic and demographic variables. This study corroborates that households are the principal sources of urban solid wastes and it is emphasized that management strategies must preponderate households to be successful. In addition, this information is important to establish strategies for an integral management of urban solid wastes in developing countries.
基金supported by the National Institute of Nuclear Researches(project CB-505)CONACyT(project 254665)SEP-TecNM(project 2340.09-P)
文摘In the present investigation, two zeolite-rich tuffs from Guaymas and El Cajon（State of Sonora）, which were conditioned with a sodium chloride solution and subsequently modified with a thiourea solution, were chosen to evaluate the removal of Cd from aqueous systems. The zeolitic materials were characterized by scanning electron microscopy and X-ray diffraction. The surface area was also determined. The experiments were performed in a batch system, and the influences of p H, contact time between phases, and the concentration of Cd in the solution on the adsorption by sodium or thiourea-modified zeolite-rich tuff were investigated. It was found that the efficiency of Cd ion removal from aqueous solutions is influenced by the p H of the aqueous systems. The Cd adsorption kinetic data were well fitted to a pseudo-second-order model in all cases. The Langmuir and Langmuir–Freundlich isotherms adequately described the Cd sorption behavior by the zeolite from El Cajon pretreated with Na Cl and the zeolite from Guaymas modified with thiourea, respectively.
