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A novel and green CO2 adsorbent developed with high adsorption properties in a coal mine refuge chamber

Du, Yan, Gai, Wen-mei, Jin, Long-zhe
Journal of cleaner production 2018 v.176 pp. 216-229
adsorbents, adsorption, carbon dioxide, coal, dust, engineering, humidity, kinetics, models, pollution, porosity, sodium hydroxide, sorption isotherms, surface area, temperature
A novel and modified soda lime with higher adsorption rate and capacity was developed. According to the multi-index orthogonal experiments, the best combinations of soda lime with different mass fractions is CMSS 8.5%, H2O 10.5% and NaOH 8.5% and the order of influence on CO2 adsorption rate of different compositions (mass fraction) is NaOH > H2O > CMSS. The modified soda lime was characterized by using various techniques for their pore structure and surface area. The porosity of optimal soda lime is 27.13%, total pore volume 0.19 mL/g and total surface area 6.10 m²/g. The Langmuir isotherm model fitted best among the three isotherm models, indicating the maximum adsorption takes up at 25 °C. The CO2 adsorption kinetic study was performed by using two kinetic models, and the second order was found fitted best with the experimental data with maximum error% of 2.28%. The adsorption rate still remains at a high level in an environment with high temperature and high humidity (humidity 70% and temperature 30 °C). Moreover, technical parameters appropriate for engineering applications were analyzed and calculated. It can be concluded that the novel adsorbent has several advantages, such as its being lower in cost, higher in efficiency, more stable in nature, higher in strength, few in secondary pollution and lower in dust outflow. It was demonstrated that the adsorption capacity increased by 36.2% and the adsorption rate increased by 39.5%.