Para-xylene was chosen as the probe molecule to study adsorption thermodynamics and diffusion kinetics on NaY zeolite and composite structured NaY zeolite synthesized by in-situ crystallization from kaolin microsphere...Para-xylene was chosen as the probe molecule to study adsorption thermodynamics and diffusion kinetics on NaY zeolite and composite structured NaY zeolite synthesized by in-situ crystallization from kaolin microsphere(designated as Na Y/kaolin composites) separately, using a high precision intelligent gravimetric analyzer(IGA). The adsorption isotherms showed normal Langmuir type-Ⅰ behaviors. The increased adsorption heat with an increasing p-xylene coverage supported a mechanism of phase transition, diffusion and re-arrangement of p-xylene molecules during the adsorption process. The rearrangement seemed to be most pronounced at an adsorption loading of 2.13 and 2.29 mmol/g for Na Y zeolite and Na Y/kaolin composites respectively. Compared with Na Y zeolite, a 2—3 times higher in the diffusion coefficient of p-xylene was observed on Na Y/kaolin composites when the pressure was more than 50 Pa. Temperature-programmed desorption(TPD) of p-xylene on two samples from room temperature to 450 ℃ at a special loading has also been investigated by IGA. Results showed only single desorption peak appeared for Na Y zeolite, indicating that adsorption can only occur in the super-cage structure. Comparably, there were two different peaks for in-situ synthesized Na Y zeolite, corresponding to the two thermo desorption processes in both super-cage structure and the channels provided by kaolin, respectively.Key words:展开更多
Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the ...Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.展开更多
The metal-organic framework HKUST-1 was prepared by different solvents. Several analytical tools such as scanning electron microscope (SEM), X-ray diffraction (XRD), N2 adsorption-desorption have been used to characte...The metal-organic framework HKUST-1 was prepared by different solvents. Several analytical tools such as scanning electron microscope (SEM), X-ray diffraction (XRD), N2 adsorption-desorption have been used to characterize the as-synthesized samples. Meanwhile, the solubility of organic ligands in solvents and the CH4 adsorption capacity of samples were also detected. The results showed that HKUST-1 prepared with N,N-dimethylformamide (DMF) used as solvent exhibited excellent CH4 adsorption performance. Further studies have shown that the improved CH4 adsorption properties could be attributed to higher solubility of the ligand 1,3,5-benzenetricarboxylic acid in DMF and larger specific surface areas. This work can provide a novel sight for preparing highly efficient CH4 adsorbent materials by improving the solubility of ligand.展开更多
To prepare potassium titanate catalyst, a novel citrate acid complex-combustion method using CH3COOK and Ti（OC4H9）4 as raw materials was developed. The crystalline phase and surface morphology of K2Ti205 were invest...To prepare potassium titanate catalyst, a novel citrate acid complex-combustion method using CH3COOK and Ti（OC4H9）4 as raw materials was developed. The crystalline phase and surface morphology of K2Ti205 were investigated by X-ray diffraction （XRD）, field emission scanning electron microscope （FE-SEM） and transmission electron microscope （TEM）. The impact of some factors, such as the type of contact between K2Ti205 and soot, the content of water vapor and SO2 in exhaust, and the repeated use on catalytic activity of K2Ti205 were studied by temperature programmed reaction （TPR）. A comparison between the new method and the reported ones on catalytic activity of potassium titanate was investigated. The results showed that K2Ti205 had high catalytic activity and good stability.展开更多
K2Ti2O5 and LixK2-xTi2O5 samples with varying K contents （x=0.125, 0.15, 0.3）, targeted on removal of two main environmental pollutants： PM and NOx, were synthesized by the solid state method using TiO2, KNO3 and L...K2Ti2O5 and LixK2-xTi2O5 samples with varying K contents （x=0.125, 0.15, 0.3）, targeted on removal of two main environmental pollutants： PM and NOx, were synthesized by the solid state method using TiO2, KNO3 and LiOH-H2O as starting materials and were characterized by X-ray diffractometry, scanning electron microscopy, and BET. The catalytic activity of titanate catalysts on PM oxidation was evaluated using the temperature programmed oxidation （TPO） method. The test results showed that the perovskite structure of K2Ti205 was still retained after doping a small amount of Li, and the catalytic performance of LixK2-xTi2O5 had been improved significantly compared with that of K2Ti2O5. Li0.15K1.85Ti205 catalyst had the highest catalytic activity with an ignition temperature of 210℃ and a peak temperature of 290℃. The catalytic activity of both K2Ti2O5 and LixK2-xTi2O5 under intimate contact was higher than that under loose contact. When the exhaust gas flow rate was around 100 mL/min, the catalyst samples showed a highest activity. The Li doped K2Ti2O5 could be an excellent candidate for PM oxidation due to its high oxidation activity, water stability, resistance to sulfur poisoning and economical advantages.展开更多
An approach for dominating the channel form of the flexible MIL-53(Fe)was developed by using a surfactant-assisted modified method.The surfactant tetraethylammonium hydroxide(TEAOH)can control the channel form of MIL-...An approach for dominating the channel form of the flexible MIL-53(Fe)was developed by using a surfactant-assisted modified method.The surfactant tetraethylammonium hydroxide(TEAOH)can control the channel form of MIL-53(Fe)to be a“closed-pore”form,whereas the surfactant polyoxyethylene polyoxypropylene polyoxyethylene(P123)or polyvinyl alcohol(PVA)can dominate the channel form of MIL-53(Fe)for a“large-pore”form.The photocatalytic performance of MIL-53(Fe)with different channel forms was investigated through the degradation of rhodamine B(Rh B)in water under violet light irradiation.The results showed that MIL-53(Fe)with a“large-pore”form exhibited higher photocatalytic activity than that of MIL-53(Fe)with a“closed-pore”form.MIL-53(Fe)modified with PVA exhibit the best photocatalytic activity for degrading almost 100%Rh B in 90 minutes.展开更多
基金financial support from the National Natural Science Foundation of China(20976077,21076100)the National 973 Foundation of China(2007CB216403)
文摘Para-xylene was chosen as the probe molecule to study adsorption thermodynamics and diffusion kinetics on NaY zeolite and composite structured NaY zeolite synthesized by in-situ crystallization from kaolin microsphere(designated as Na Y/kaolin composites) separately, using a high precision intelligent gravimetric analyzer(IGA). The adsorption isotherms showed normal Langmuir type-Ⅰ behaviors. The increased adsorption heat with an increasing p-xylene coverage supported a mechanism of phase transition, diffusion and re-arrangement of p-xylene molecules during the adsorption process. The rearrangement seemed to be most pronounced at an adsorption loading of 2.13 and 2.29 mmol/g for Na Y zeolite and Na Y/kaolin composites respectively. Compared with Na Y zeolite, a 2—3 times higher in the diffusion coefficient of p-xylene was observed on Na Y/kaolin composites when the pressure was more than 50 Pa. Temperature-programmed desorption(TPD) of p-xylene on two samples from room temperature to 450 ℃ at a special loading has also been investigated by IGA. Results showed only single desorption peak appeared for Na Y zeolite, indicating that adsorption can only occur in the super-cage structure. Comparably, there were two different peaks for in-situ synthesized Na Y zeolite, corresponding to the two thermo desorption processes in both super-cage structure and the channels provided by kaolin, respectively.Key words:
基金the financial support by the Natural Science Foundation of Liaoning Province of China (Grant No. 2013020122)the National Natural Science Foundationof China (Grant No. 21076100 and 51308045)the financial support by the PetroChina Company Limited (Grant No. 10-01A-01-01-01)
文摘Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.
基金financially supported by the National Natural Science Foundation of China (21476101)the Liaoning Provincial Education Department Foundation (L2015304)the funds of Liaoning Shihua University (2019XJJ-005)
文摘The metal-organic framework HKUST-1 was prepared by different solvents. Several analytical tools such as scanning electron microscope (SEM), X-ray diffraction (XRD), N2 adsorption-desorption have been used to characterize the as-synthesized samples. Meanwhile, the solubility of organic ligands in solvents and the CH4 adsorption capacity of samples were also detected. The results showed that HKUST-1 prepared with N,N-dimethylformamide (DMF) used as solvent exhibited excellent CH4 adsorption performance. Further studies have shown that the improved CH4 adsorption properties could be attributed to higher solubility of the ligand 1,3,5-benzenetricarboxylic acid in DMF and larger specific surface areas. This work can provide a novel sight for preparing highly efficient CH4 adsorbent materials by improving the solubility of ligand.
基金the financial supports provided for this research by the Education Department of Liaoning Province of China(No.2009T061)the Ministry of Education of China(No.[2010]1561)
文摘To prepare potassium titanate catalyst, a novel citrate acid complex-combustion method using CH3COOK and Ti（OC4H9）4 as raw materials was developed. The crystalline phase and surface morphology of K2Ti205 were investigated by X-ray diffraction （XRD）, field emission scanning electron microscope （FE-SEM） and transmission electron microscope （TEM）. The impact of some factors, such as the type of contact between K2Ti205 and soot, the content of water vapor and SO2 in exhaust, and the repeated use on catalytic activity of K2Ti205 were studied by temperature programmed reaction （TPR）. A comparison between the new method and the reported ones on catalytic activity of potassium titanate was investigated. The results showed that K2Ti205 had high catalytic activity and good stability.
基金supports provided for this research by the Education Department of Liaoning Province of China (No. 2009T061)Ministry of Education of China (No. [2010] 1561)
文摘K2Ti2O5 and LixK2-xTi2O5 samples with varying K contents （x=0.125, 0.15, 0.3）, targeted on removal of two main environmental pollutants： PM and NOx, were synthesized by the solid state method using TiO2, KNO3 and LiOH-H2O as starting materials and were characterized by X-ray diffractometry, scanning electron microscopy, and BET. The catalytic activity of titanate catalysts on PM oxidation was evaluated using the temperature programmed oxidation （TPO） method. The test results showed that the perovskite structure of K2Ti205 was still retained after doping a small amount of Li, and the catalytic performance of LixK2-xTi2O5 had been improved significantly compared with that of K2Ti2O5. Li0.15K1.85Ti205 catalyst had the highest catalytic activity with an ignition temperature of 210℃ and a peak temperature of 290℃. The catalytic activity of both K2Ti2O5 and LixK2-xTi2O5 under intimate contact was higher than that under loose contact. When the exhaust gas flow rate was around 100 mL/min, the catalyst samples showed a highest activity. The Li doped K2Ti2O5 could be an excellent candidate for PM oxidation due to its high oxidation activity, water stability, resistance to sulfur poisoning and economical advantages.
基金This research was supported by the Natural Science Foundation of Guangdong Province(No.2018A030307058)the Projects of Talents Recruitment of GDUPT(72100003177).
文摘An approach for dominating the channel form of the flexible MIL-53(Fe)was developed by using a surfactant-assisted modified method.The surfactant tetraethylammonium hydroxide(TEAOH)can control the channel form of MIL-53(Fe)to be a“closed-pore”form,whereas the surfactant polyoxyethylene polyoxypropylene polyoxyethylene(P123)or polyvinyl alcohol(PVA)can dominate the channel form of MIL-53(Fe)for a“large-pore”form.The photocatalytic performance of MIL-53(Fe)with different channel forms was investigated through the degradation of rhodamine B(Rh B)in water under violet light irradiation.The results showed that MIL-53(Fe)with a“large-pore”form exhibited higher photocatalytic activity than that of MIL-53(Fe)with a“closed-pore”form.MIL-53(Fe)modified with PVA exhibit the best photocatalytic activity for degrading almost 100%Rh B in 90 minutes.
