Separation and purification of dodecanedioic acid (DDDA) from its homologous compounds were studied experimentally by falling film crystallization (FFC). The influences of various operation parameters, including cryst...Separation and purification of dodecanedioic acid (DDDA) from its homologous compounds were studied experimentally by falling film crystallization (FFC). The influences of various operation parameters, including crystallizing time, flow rate of melt and temperature of glycerine bath, on purity of DDDA and crystallizing rate were investigated. Over 99% (by mole) DDDA was obtained for a feed composition of 96% (by mole). The main factors affecting the separation efficiency are flow rate of melt and temperature of glycerine bath. The crystallizing layer of DDDA was further purified by sweating and blasting. A set of optimized operation data are provided for better understanding the mechanism of heat and mass transfer in FFC, and for further industrial application of DDDA purification process.展开更多
Water extracts prepared from seven varieties of olive leaves native to the Mediterranean area but planted in Sichuan province, P.R. China, namely Frantoiao, Leccio, Ezhi, Picholine, Pendollino, Chenggu and Huaou 9#, w...Water extracts prepared from seven varieties of olive leaves native to the Mediterranean area but planted in Sichuan province, P.R. China, namely Frantoiao, Leccio, Ezhi, Picholine, Pendollino, Chenggu and Huaou 9#, were examined for their total phenonic and flavonoid contents, antioxidant capacity. Total phenolic and flavonoid content were measured by Folin-Ciocalteu method and a colorimetric method, respectively. ABTS＋ method and FRAP were used for examining antioxidant activity. Response surface methodology （RSM） was used for optimizing the extract condition. Under the optimum condition, the total phenolic and flavonoid content of aqueous extracts of the dry olive leaves （DOL） ranged from 40.27 to 56.58 mg gallic acid （GAE）/g DOL and 21.59 to 33.72 mg catechin （CE）/g DOL in June, 34.31 to 52.81 mg GAE/g DOL and 17.11 to 23.53 mg CE/g DOL in November. The ABTS＋ method and FRAP ranged from 0.23 to 0.35 mmol trolox （TE）/g DOL and 313.01 to 409.69 μmol Fe2＋/g DOL in June, 0.19 to 0.30 mmol TE/g DOL and 254.69 to 418.10 pmol Fe2＋/g DOL in November. Our results revealed that the total phenolic and flavonoid, or antioxidant capacity of the water extract were higher in June than November. Moreover, it was noticed that the antioxidant activity depends on the flavonoid and phenolic.展开更多
According to the chemical and mineral composition characteristics of the fly ash,alumina can be extracted from fly ash through the calcining method by using sodium carbonate and calcium carbonate additives.The effects...According to the chemical and mineral composition characteristics of the fly ash,alumina can be extracted from fly ash through the calcining method by using sodium carbonate and calcium carbonate additives.The effects on leaching rate of alumina have been investigated. The results showed that the fly ash can be activated effectively and the leaching rate of alumina can be improved to more than 92% through this method. The best process parameters were the ratio of raw materials,i. e. the material weight ratio of fly ash,calcium carbonate and sodium carbonate was 1. 0∶1. 2∶0. 9. The activating temperature was 850℃-900℃,activating time was 3 h. This process has a potential application prospect and improves the value of comprehensive utilization of fly ash.展开更多
文摘Separation and purification of dodecanedioic acid (DDDA) from its homologous compounds were studied experimentally by falling film crystallization (FFC). The influences of various operation parameters, including crystallizing time, flow rate of melt and temperature of glycerine bath, on purity of DDDA and crystallizing rate were investigated. Over 99% (by mole) DDDA was obtained for a feed composition of 96% (by mole). The main factors affecting the separation efficiency are flow rate of melt and temperature of glycerine bath. The crystallizing layer of DDDA was further purified by sweating and blasting. A set of optimized operation data are provided for better understanding the mechanism of heat and mass transfer in FFC, and for further industrial application of DDDA purification process.
文摘Water extracts prepared from seven varieties of olive leaves native to the Mediterranean area but planted in Sichuan province, P.R. China, namely Frantoiao, Leccio, Ezhi, Picholine, Pendollino, Chenggu and Huaou 9#, were examined for their total phenonic and flavonoid contents, antioxidant capacity. Total phenolic and flavonoid content were measured by Folin-Ciocalteu method and a colorimetric method, respectively. ABTS＋ method and FRAP were used for examining antioxidant activity. Response surface methodology （RSM） was used for optimizing the extract condition. Under the optimum condition, the total phenolic and flavonoid content of aqueous extracts of the dry olive leaves （DOL） ranged from 40.27 to 56.58 mg gallic acid （GAE）/g DOL and 21.59 to 33.72 mg catechin （CE）/g DOL in June, 34.31 to 52.81 mg GAE/g DOL and 17.11 to 23.53 mg CE/g DOL in November. The ABTS＋ method and FRAP ranged from 0.23 to 0.35 mmol trolox （TE）/g DOL and 313.01 to 409.69 μmol Fe2＋/g DOL in June, 0.19 to 0.30 mmol TE/g DOL and 254.69 to 418.10 pmol Fe2＋/g DOL in November. Our results revealed that the total phenolic and flavonoid, or antioxidant capacity of the water extract were higher in June than November. Moreover, it was noticed that the antioxidant activity depends on the flavonoid and phenolic.
文摘According to the chemical and mineral composition characteristics of the fly ash,alumina can be extracted from fly ash through the calcining method by using sodium carbonate and calcium carbonate additives.The effects on leaching rate of alumina have been investigated. The results showed that the fly ash can be activated effectively and the leaching rate of alumina can be improved to more than 92% through this method. The best process parameters were the ratio of raw materials,i. e. the material weight ratio of fly ash,calcium carbonate and sodium carbonate was 1. 0∶1. 2∶0. 9. The activating temperature was 850℃-900℃,activating time was 3 h. This process has a potential application prospect and improves the value of comprehensive utilization of fly ash.
