Co-crystalline zeolite FAU/LTA-0 was synthesized by hydrothermal method from lithium slag. To make the most of excess silicon and alkali sources in mother liquid derived from FAU/LTA-0, zeolite FAU/LTA-I b was synthes...Co-crystalline zeolite FAU/LTA-0 was synthesized by hydrothermal method from lithium slag. To make the most of excess silicon and alkali sources in mother liquid derived from FAU/LTA-0, zeolite FAU/LTA-I b was synthesized in the same method with the use of mother liquid by adding a certain amount of aluminum source. Influences of different adding ways of aluminum source and recycling dosages of mother liquid on synthesis of zeolites FALl/ LTA with mother liquid were investigated. The phase, microstructure and thermostability of FAU/LTA-0 and FAU/LTA-lb were characterized by XRD, SEM and TG-DTA. The calcium and magnesium cation exchange capacities （CECs） of the zeolites were determined. The results have shown that co-crystalline zeolite can be synthesized with the use of mother liquid by adding aluminum source after 2 h of reaction. Compared with FAU/LTA-0, the crystal twinning structure of FAU/LTA-lb became weaker, the grain size was smaller, and the thermostability was better. With a lower dosage of mother liquid, the content of P-type impurity in product decreased significantly, and the content of LTA phase increased. The reuse rate of mother liquid can reach 48%. The CECs of FAU/LTA-I b-150 can reach 343 mg CaCO3. g-1 and 180 mg MgC03. g-1, showing more excellent adsorption capacities than FAU/LTA-0 and commercial zeolite 4A. The full recycling use of mother liquid to synthesize zeolite FAU/LTA which can be applied for detergent not only improves resource utilization but also reduces oroduction cost.展开更多
LTA (Linde Type A) molecular sieve has widely used in adsorption and separation due to its regular pore structure, high thermal stability and chemical stability. Copper-exchanged LTA (Cu-LTA) zeolite membranes with en...LTA (Linde Type A) molecular sieve has widely used in adsorption and separation due to its regular pore structure, high thermal stability and chemical stability. Copper-exchanged LTA (Cu-LTA) zeolite membranes with enhanced water flux of ethanol dehydration were developed through copper ion exchange of Na-LTA zeolite membrane. In the first step, a thin and well intergrown Na-LTA zeolite membrane was prepared on macroporousα-Al2O3 tube which was modified by 3-aminopropyltriethox-ysilane (APTES). Afterwards, copper exchange of the as-synthesized Na-LTA zeolite membranes was done to prepare Cu-LTA zeolite membrane. According to characterizations of XRD, FESEM, and XPS, both the morphology and structure of the Cu-LTA zeolite membranes are identical to those of the Na-LTA zeolite membranes, and there are no cracks and pinholes are found in the membrane layer. Attributing to a wider pore diameter because two sodium ions of Na-LTA framework are replaced by one copper ion, the Cu-LTA zeolite membrane displays a higher water flux in the separation of ethanol/water mixture than Na-LTA membranes. At 75 °C, the water flux of the Cu-LTA zeolite membrane is 3.52 kg m^-2 h^-1 with water/ethanol separation factor of 3591, while the water flux of the Na-LTA zeolite membrane is only 1.65 kg m^-2 h^-1 with water/ethanol separation factor of 4082.展开更多
基金Supported by the National Natural Science Foundation of China(51476074)
文摘Co-crystalline zeolite FAU/LTA-0 was synthesized by hydrothermal method from lithium slag. To make the most of excess silicon and alkali sources in mother liquid derived from FAU/LTA-0, zeolite FAU/LTA-I b was synthesized in the same method with the use of mother liquid by adding a certain amount of aluminum source. Influences of different adding ways of aluminum source and recycling dosages of mother liquid on synthesis of zeolites FALl/ LTA with mother liquid were investigated. The phase, microstructure and thermostability of FAU/LTA-0 and FAU/LTA-lb were characterized by XRD, SEM and TG-DTA. The calcium and magnesium cation exchange capacities （CECs） of the zeolites were determined. The results have shown that co-crystalline zeolite can be synthesized with the use of mother liquid by adding aluminum source after 2 h of reaction. Compared with FAU/LTA-0, the crystal twinning structure of FAU/LTA-lb became weaker, the grain size was smaller, and the thermostability was better. With a lower dosage of mother liquid, the content of P-type impurity in product decreased significantly, and the content of LTA phase increased. The reuse rate of mother liquid can reach 48%. The CECs of FAU/LTA-I b-150 can reach 343 mg CaCO3. g-1 and 180 mg MgC03. g-1, showing more excellent adsorption capacities than FAU/LTA-0 and commercial zeolite 4A. The full recycling use of mother liquid to synthesize zeolite FAU/LTA which can be applied for detergent not only improves resource utilization but also reduces oroduction cost.
基金financially supported by the National Natural Science Foundation of China (Nos. 21761132003, 21606246)Ningbo Science and Technology Innovation Team (No. 2014B81004)
文摘LTA (Linde Type A) molecular sieve has widely used in adsorption and separation due to its regular pore structure, high thermal stability and chemical stability. Copper-exchanged LTA (Cu-LTA) zeolite membranes with enhanced water flux of ethanol dehydration were developed through copper ion exchange of Na-LTA zeolite membrane. In the first step, a thin and well intergrown Na-LTA zeolite membrane was prepared on macroporousα-Al2O3 tube which was modified by 3-aminopropyltriethox-ysilane (APTES). Afterwards, copper exchange of the as-synthesized Na-LTA zeolite membranes was done to prepare Cu-LTA zeolite membrane. According to characterizations of XRD, FESEM, and XPS, both the morphology and structure of the Cu-LTA zeolite membranes are identical to those of the Na-LTA zeolite membranes, and there are no cracks and pinholes are found in the membrane layer. Attributing to a wider pore diameter because two sodium ions of Na-LTA framework are replaced by one copper ion, the Cu-LTA zeolite membrane displays a higher water flux in the separation of ethanol/water mixture than Na-LTA membranes. At 75 °C, the water flux of the Cu-LTA zeolite membrane is 3.52 kg m^-2 h^-1 with water/ethanol separation factor of 3591, while the water flux of the Na-LTA zeolite membrane is only 1.65 kg m^-2 h^-1 with water/ethanol separation factor of 4082.
