Yuguang Mao,Xiang Hu,Sarra Drissi,Wei Chen,Caijun Shi
To address the challenge posed by the carbonation product layer formed on recycled cement paste powder (RCPP) on the efficiency and degree of carbonation, CO 2 -loaded monoethanolamine (MEA) “microcapsules” were used. The CO 2 within MEA was released by heating after the formation of the dense carbonation products layer on RCPP to provide an additional internal CO 2 source to penetrate into the uncarbonated layer. Results showed that using CO 2 dissolved in 15 %, 30 %, and 45 % MEA aqueous solution increased the carbonation degree of RCPP by 10.8 %, 11.2 %, and 13.8 %, respectively, compared to RCPP wet carbonated in water. In addition to calcite, vaterite and aragonite were observed in the CO 2 -loaded MEA carbonated RCPP. The long-term compressive strength of cement pastes with 30 % CO 2 -loaded MEA carbonated RCPP increased, and the porosity decreased compared to cement paste with RCPP wet carbonated in water. However, MEA negatively affected the early compressive strength of the cement paste.
Hydrothermal carbonization of lignocellulosic biomass results in hydrochar with abundant surface functionality and low degree of carbonization. In this work, Cola Shell was subjected to a pretreatment with the Deep Eutectic Solvent (DES) prior to hydrothermal carbonization under different conditions (210 ºC and 260 ºC). The aim was to ascertain the impact of pretreatment with DES on the properties of hydrochars. The results show that pretreatment with DES at 110 ºC favors the disintegration of hemicellulose while promoting the cellulose hydrolysis and dehydration. The lignin removal formed a snow cloud of particles on hydrochar surface, which further undergoes polymerization at a high HTC temperature to form a cluster of fibrous carbonaceous material, contributing to increase the degree of carbonization and thermal stability of hydrochar. DES pretreatment also reduced structural defects while increasing the cellulose crystallinity. In addition, DES pretreatment increased the nitrogen content and energy yield without affecting the calorific value of hydrochar-derived Cola Nut Shell.
危险品化学品经营许可证（带存储）