MFI-Type Zeolite Membranes for Pervaporation Separation of Dichlorobenzene Isomers

Abstract

MFI-type zeolitic membranes were prepared on the porous α-A 2 O 3 support to investigate the separation properties of dichlorobenzene isomers. The pervaporation tests were performed with unary and binary isomer mixtures at 333 K. The results indicate that the silicalite membranes, irrespective of being synthesized by the templated or template-free method, are permeable for all dichlorobenzene isomers. The pervaporation fluxes of the pure dichlorobenzene isomers decrease in the order p-DCB > o-DCB > m-DCB. For the binary pervaporation system, the dichlorobenzene fluxes are all less than those with a single component due to the binary interactions between DCB isomers and between the DCB isomer and the zeolite membrane. Comparatively, the template-free MFI-type zeolite exhibits higher selectivity for dichlorobenzene isomers due to less inter-crystalline gaps. The separation factors for p-/o-DCB and p-/m-DCB can reach 16.7 and 22.0, respectively.

Preparation of modified MFI-type/PDMS composite membranes for the separation of dichlorobenzene isomers via pervaporation

“…This phenomenon can be explicated by two reasons. 15 One is the distortion of neighbouring chloro-groups in the o -DCB isomers. The other one is the distorted expansion of the silicalite-1 zeolites when contacting aromatic molecules.…”

“…The molecular sizes of the DCB isomers (kinetic diameter: p -DCB, 0.58 nm; o -DCB and m -DCB, 0.68 nm) are similar to the pore size of MFI-type zeolites. 15 Each DCB isomer has different chemical affinities and adsorption properties with the MFI-type zeolite pores, which was proved by Guo and Long. 16 However, the disadvantages of the high thermal effect, difficult zeolite regeneration, huge zeolite dosage and complex solid waste treatment limit the development of zeolite adsorption methods in DCB isomer separation (also granular silicalite-1 zeolite adsorbents).…”

“…The results demonstrate that silicalite-1/Al 2 O 3 membranes exhibit good separation properties. 15 Unfortunately, the large-scale preparation of silicalite-1/Al 2 O 3 membranes in the industry is still a great technical challenge, which hinders its future industrial applications. Hence, finding new materials for the separation of DCB isomers is extremely urgent.…”

A Facile Method to Synthesize b-Oriented Silicalite-1 Thin Film

“…The zeolite thin film/membranes are among inorganic membranes which consist of hydrated crystalline aluminosilicates with open three-dimensional framework structures, made up of SiO 4 and AlO 4 tetrahedrons linked by sharing their oxygen atom to form regular intracrystalline cavities and channels of atomic dimensions. The research of zeolite thin film/membrane is an attractive topic of inorganic membrane technology due to their various applications, such as gas or liquid separation [ 1 , 2 , 3 , 4 , 5 ], chemical sensors [ 6 , 7 , 8 ], catalytic membrane [ 9 , 10 ], dielectric thin films [ 11 , 12 ], corrosion-resistant coatings [ 12 , 13 ] and biological application [ 14 ].…”

Solvent Regeneration by Thermopervaporation in Subsea Natural Gas Dehydration: An Experimental and Simulation Study

“…Pervaporation has been widely applied to liquid−liquid/ vapor−liquid separation with an emphasis on alcohol/water systems, 11−21 bio-oil dehydration, 22 hazardous substances and organic solvent removal from water, 23,24 solvent regeneration from complex mixtures, 25 isomer separation, 26 and glycol dehydration. 27−32 The pervaporation process benefits from the membrane selectivity in addition to the vapor−liquid equilibrium selectivity.…”