Study on the synthesis and mechanism of FAU zeolite membrane by alkali modification in situ aging microwave method
This study proposed a novel method for synthesizing dense and pure phase FAU zeolite membranes using in situ aging microwave method by alkali modification.The role of sodium hydroxide on carrier and the growth mechanism of FAU zeolite membranes were investigated through XRD,SEM,ATR-FTIR,and pervaporation testing.By comparing the unmodified carriers,it was found that with the modification of sodium hydroxide,the nucleation and growth of FAU crystals were significantly promoted on the carrier surface.The growth process of FAU zeolite membrane was characterized,it was found that during the aging process,the bulk gel first formed FAU secondary structural units under the promotion of alkali on the carrier surface,followed by the formation of flaky FAU crystals.With the prolongation of aging time,it gradually became block like crystals and crosslinked.Finally,under the action of microwave,fine defects were eliminated to obtain a dense pure phase FAU membrane.At the same time,the effect of alkali concentration on the carrier was investigated.Through optimization,it was found that the carrier modified in a Na2O concentration of 2.95％solution can obtain the FAU membrane with the best pervaporation performance.In a mixed ethanol/water(90/10)solution at 60 ℃,the average permeation flux of the FAU membrane is 2.19 kg/(m2·h),and the water content on the permeation side is 100％.This indicates that it has high flux and selectivity,demonstrating good industrial application prospects.
NETL
NSTL
万方数据
