URBANREC

An alternative clean regeneration method to calcination on special grade resins, i.e. Nafion, is introduced. The reactivation strategy makes use of advanced oxidation processes (Fenton and non-Fenton) to remove the organic deposits generated from sequential catalytic cycles. Hot water treatment was considered as a control case to evaluate the extraction capacity of water itself at the oxidative conditions. Advanced oxidation processes were effective in reactivating the Nafion SAC-13 resin, which also rendered a cleaner and more sustainable reactivation process. Beta zeolite was studied as model fouled system prior to the Nafion SAC-13. Even though zeolites are considered to be thermally stable, this approach can be used when a full preservation of the acid sites is required. As far as resin Nafion SAC-13 is concerned, organic species deposition was found to be responsible of a selective poisoning of the sulfonic groups in Nafion, with a consequent drop in catalytic activity on the octanoic acid esterification with methanol. The Nafion resin was reactivated either with H2O2 or with Fenton chemistry; the resin remained stable under these oxidative conditions, which is the benefit of the presented non­thermal methodologies as compared to calcination. The optimal method showed full recovery of the initial activity and 90% of the final conversion. This methodology seems attractive for a whole-range of organic catalytic reactions, including those related with biomass valorization, that require the use of highly acidic catalysts, such as acidic resins, in liquid phase reactions.

» Author: Ekaterina Ponomareva, Marco-Antonio López-Martínez, Daan Wigger, Maria V. Morales, Ignacio Melián-Cabrera

» Reference: 10.1016/j.apcata.2018.10.035

» Publication Date: 30/10/2018

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