Adsorption of C8 Aromatics Isomers in Porous Clay Heterostructures Using the Headspace Technique

The separation of C₈ aromatics isomers is an important issue in the petrochemical industry. The C₈ aromatics fraction consists of four isomers: o-xylene (OX), m-xylene (MX), p-xylene (PX) and ethylbenzene (EB). They are the raw material for plastics, dyes, synthetic fibers and other products. The faujasite structure, especially Y zeolite, has been intensively studied and used for the separation of xylenes, mainly for p-xylene separation. However, a group of porous materials that appear as promising in the liquid phase separation is the porous clay heterostructures (PCH). In this study, the selective separation of xylene isomers in different PCHs samples was investigated. Porous clay heterostructures with Zr, Ti and Si (PCH-Zr, PCH-Ti and PCH-Si) were evaluated. A headspace technique was applied to acquire equilibrium data for adsorption of xylenes using small samples. Meta-xylene selectivity in relation to all the other C₈ aromatics was observed for the PCH samples. For PCH-Si, meta-xylene/ethylbenzene selectivity of 4.3 was obtained.