Polymeric foams
Hossein Hazrati; Nader Jahanbakhshi; Mohammad Rostamizadeh
Abstract
In this study, the response surface methodology (RSM) based on the central composite design (CCD) was used to optimize the preparation condition of polypropylene-grafted maleic anhydride (PP-g-MA) microporous membrane by thermally-induced phase separation (TIPS) method. A mixture of dibutyl phthalate ...
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In this study, the response surface methodology (RSM) based on the central composite design (CCD) was used to optimize the preparation condition of polypropylene-grafted maleic anhydride (PP-g-MA) microporous membrane by thermally-induced phase separation (TIPS) method. A mixture of dibutyl phthalate (DBP) and dioctyl phthalate (DOP) was used as diluent. The effect of polymer composition and quenching bath temperature on the morphology and performance of the fabricated microporous membranes was investigated by using RSM. Analysis of variance (ANOVA) was used to determine which variables and interactions between variables had a significant effect on our responses. The ANOVA revealed that the bath temperature was the most significant variable associated with porosity and pure water flux responses and the polymer concentration was the most significant variable associated with tensile response. The obtained results also showed that with increasing the polymer concentration and decreasing the quenching bath temperature, the membrane porosity and pure water flux decreased, whereas the membrane tensile increased. The regression equations were reasonably validated and used to predict and optimize the performance of PP-g-MA membranes within the limits of the variables. Finally, the maximum responses (flux of 115.6 L/m2h, porosity of 62% and tensile of 1.6 MPa) were obtained under the following conditions: polymer concentration of 28.5 wt% and temperature of 329 K. Further, comparison of laboratory-made and commercial membranes in a membrane bioreactor (MBR) system showed that the rate of membrane fouling was decreased by 4.2 times.
Olefin oligomerization
Mohammad Rostamizadeh; Fereydoon Yaripour; Hossein Hazrati
Abstract
Highly siliceous ZSM-5 nanocatalysts can dehydrate methanol to a wide range of hydrocarbons. In this study, the development of hierarchical H-ZSM-5 nanocatalysts (Si/Al=200) were reported for the methanol-toolefins (MTO) reaction. The nanocatalysts were prepared through a hydrothermal technique and treated ...
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Highly siliceous ZSM-5 nanocatalysts can dehydrate methanol to a wide range of hydrocarbons. In this study, the development of hierarchical H-ZSM-5 nanocatalysts (Si/Al=200) were reported for the methanol-toolefins (MTO) reaction. The nanocatalysts were prepared through a hydrothermal technique and treated by NaOH desilication. The parent and desilicated nanocatalysts were characterized using FE-SEM, XRD, FTIR, NH3-TPD and N2 adsorption-desorption techniques. The mesoporosity increased five times without significant collapse of the crystalline framework as a result of the appropriate desilication of H-ZSM-5 nanocatalyst. For the nanocatalyst, a high surface area of 189.5 m2 g-1, mesopore volume of 0.35 cm3 g-1 and well-adjusted strong acidity of 0.16 mmol NH3 g-1 resulted in a high methanol conversion of 100%, high propylene selectivity of 43% and low light paraffins selectivity of <8% in the MTO reaction. A broad mesopore size of 2-10 nm suppressed coke deposition and provided a long catalytic life time of 75 h. The developed high silica nanocatalyst showed a high potential for industrial applications due to its stable performance.
