A hybrid zeolitic imidazolate framework Co-IM-mIM membrane for gas separation

A zeolitic imidazolate hybrid membrane(Co-IM-mIM) containing two imidazolate ligands deposited on a macroporous α-alumina support was prepared by pre-depositing and secondary growth technique. XRD, TGA and SEM characterizations demonstrate that a stable and thin, but dense and pure-phase Co-IM-mIM membrane can be obtained on the macroporous-alumina discs in Teflon-lined autoclave at 120 °C after pre-depositing by dip-coating at room temperature. No visible cracks, pinholes or other defects were observed on the membrane layer. The gas separation studies of Co-IM-mIM membrane were carried out at 25 °C and 1×10~5 Pa, showing ideal selectivity of 6.95, 5.25, 3.40 for H_2/CO_2, H_2/N_2 and H_2/CH_4, respectively, and a permeance of 17.37× 10^(-6) mol/(m^2·s·Pa) for H_2. The influence of temperature and trans-membrane pressure on hydrogen separation and permeation was also carried out. The gas permeation and selectivity demonstrate that this membrane may have potential applications for efficient H_2 separation.

Synthesis and Separation Performance of Y-type Zeolite Membranes by Pre-Seeding Using Electrophoresis Deposition Method

Y-type zeolite membranes were synthesized by a two-step approach in which a particle seed layer was prepared by electrophoresis deposition(EPD) at first, followed by densification through secondary growth. The pre-seeding adopted the directing agent for Y-type zeolite synthesis serving as seeds. The effects of aging time of the directing agent, electrophoresis voltage and electrophoresis deposition time on seed layers quality as well as the quality of zeolite membranes were investigated. The results indicated that the zeolite seeds derived from the directing agent could be evenly deposited on substrate under certain EPD conditions. The XRD patterns of the seeded substrates after the secondary growth showed that the pure as-synthesized Y-type zeolite membranes had successfully grown on the substrates. The SEM images indicated that the substrate was covered by the highly intergrown zeolite crystals when the seeding solution employed the directing agent with an aging time of 2 days. The separation performance of zeolite membrane was evaluated using a CO_2/N2 mixture(with a mole ratio of 1:1) at different temperatures. Furthermore, the pervaporation measurements were carried out for the dehydration of isopropanol aqueous solutions with different mass fractions. The as-synthesized Y-type zeolite membranes exhibited a relatively high selectivity of water from isopropanol and sustainable permeation flux.

Effects of Honghua preserved amniotic membrane on scar healing in experimental glaucoma surgery

AIM:To investigate the efficacy and safety of Honghua preserved amniotic membrane(AM)for preventing scar formation of the filtering bleb in a rabbit model of glaucoma trabeculectomy surgery.METHODS:Totally 36 rabbits(36 eyes)were randomly divided into 3 groups:the experimental group(ocular trabeculectomy in combination with Honghua preserved AM transplantation),the control group(ocular trabeculectomy surgery in combination with AM implantation),and the blank group(single trabeculectomy).Clinical observations[including intraocular pressure(IOP),filtering blebs and complications],MassonTrichrome staining,real-time quantitative reverse transcription-polymerase chain reaction(real-time PCR),Western blot were performed on different time points(D1,D7,D14,D21 and D56)after the surgery.RESULTS:After operated for 14d,there were statistically significant differences in the filtering blebs compared to the situation before operation(P【0.05),whereas no statistically difference on that among three groups(P】0.05).After 21d,the IOP of experimental group was lowest(P【0.05).There was significant difference between control group and blank group(P【0.05).On postoperative D14,the mean number of fibroblasts in the experimental group was significantlylower(40.6±10.2)compared to those in the control group(54.4±10.8)and blank group(68.2±11.6)(P【0.05,respectively).The mean numbers of the macrophage in the experimental and control groups were respcitively significantly lower versus the blank group(P【0.05,P【0.05,respectively).Compared to that in blank group,the level of transforming growth factor-β(TGF-β1)expression in sclera and conjunctival areas was reduced in the experimental and control groups on protein and mRNA level(P【0.05),but not significant difference between these two groups(P】0.05).CONCLUSION:The trabeculectory surgery with Honghua preserved AM can control IOP,sustain the functional filtration bleb,inhibit the proliferation of fibroblasts and open the filtrating pathway on the rabbit glaucoma models.