All-silica DD3R zeolite membrane with hydrophilic-functionalized surface for efficient and highly-stable pervaporation dehydration of acetic acid

A novel strategy of all-silica zeolite membrane with hydrophilic-functionalized surface was proposed for efficient and highly-stable pervaporation dehydration of acetic acid. 3-aminopropyltriethoxysilane (APTES) was used to graft onto the surface of hollow fiber supported DD3R membrane to enhance its surface hydrophilicity and therefore improve its water/AcOH separation factor. Both pristine DD3R and obtained APTES-DD3R membranes were characterized extensively in terms of water contact angle (WCA), SEM, XRD, FT-IR and XPS for comparison. When the DD3R membrane was grafted with APTES for 1 h, the membrane surface turned from hydrophobic to hydrophilic. Under the synergetic effect of enhanced water adsorption on membrane surface and intrinsic molecule-sieving property of DD3R zeolitic pores, the APTES-DD3R membrane showed an improved separation factor of 1700 rather than that (196) of pristine DD3R membrane in separation of 10 wt% water/AcOH mixture at 348 K. Moreover, the APTES-DD3R membrane exhibited excellent stability during the PV separation, even in the presence of strong inorganic acids (HCl and H₂SO₄).