Adsorption properties of BEA zeolites and their aluminum phosphate extrudates for purification of isomaltose

Abstract

The disaccharide isomaltose is produced via an enzymatic reaction and is adsorbed to BEA zeolite. This reaction integrated adsorption can be achieved as fluidized bed as well as fixed bed. We investigated isotherms, adsorption enthalpies and sorption kinetics of BEA zeolite and extrudates with a novel aluminum phosphate sintermatrix. These extrudates contain 50% (w/w) of BEA 150 zeolites (Si/Al = 75) as primary crystals. BET-surface for extrudates is 245 m 2 ·g −1 and 487 m 2 ·g −1 for zeolite. Extrudates show a monomodal macropore structure with a maximum at 90 nm. All isotherms show a type I shape. For lower equilibrium concentrations, which occur during the enzymatic reaction, Henry's law is applied and compared to a Langmuir model. Adsorption equilibrium constant K i,L calculated from Langmuir for extrudates at 4°C is 64.7 mL·g −1 and more than twice as high as obtained from Henry's law with K i is 26.8 mL·g −1 . Adsorption on extrudates at 4°C is much stronger than on zeolite crystals where the Henry coefficient K i is 17.1 mL·g −1 . Adsorption enthalpy h Ad calculated from van't Hoff plot with the Henry equation is −44.3 kJ·mol −1 for extrudates and −29.6 kJ·mol −1 for zeolite crystals. Finally, the kinetics for ad-and desorption were calculated from the initial slope. The diffusion rate for adand desorption on extrudates were in the same range while adsorption on zeolites is three orders of magnitudes faster than desorption.

Mass transfer limitations in binderless ZSM‐5 zeolite granules during adsorption of flavour compounds from aqueous streams

“…Previous work has mainly focused on studying the mass transfer in single component systems, e.g. sugar molecules in aqueous solutions, [20][21][22][23][24][25][26] simple alcohols, ketones, and aromatics 27,28 or amino acids. 29 Relevant data is summarized in Table 1.…”

Continuous enzymatic production and adsorption of laminaribiose in packed bed reactors

“…Besides the use of zeolites in chromatographic columns for sugar separation [11], type BEA zeolites have shown a high selectivity between different carbohydrates [12] and have already been used to capture the disaccharide isomaltose in enzymatic reactions [13][14][15][16]. Besides the use of zeolites in chromatographic columns for sugar separation [11], type BEA zeolites have shown a high selectivity between different carbohydrates [12] and have already been used to capture the disaccharide isomaltose in enzymatic reactions [13][14][15][16].…”

“…Besides the use of zeolites in chromatographic columns for sugar separation [11], type BEA zeolites have shown a high selectivity between different carbohydrates [12] and have already been used to capture the disaccharide isomaltose in enzymatic reactions [13][14][15][16]. Successful combination of enzymatic production and adsorption with subsequent downstream processing has only been shown for a monoenzymatic production system where enzymatic catalysis and adsorption were integrated in a set-up comprising of fluidized bed of biocatalysts and a slurry of zeolite particles [16,20]. Successful combination of enzymatic production and adsorption with subsequent downstream processing has only been shown for a monoenzymatic production system where enzymatic catalysis and adsorption were integrated in a set-up comprising of fluidized bed of biocatalysts and a slurry of zeolite particles [16,20].…”

“…Adsorption is a well-suited unit operation for this first product removal or capture step here due to high selectivity especially in multi-component mixtures and the low operational temperature, thus avoiding hydrolysis of laminaribiose. Besides the use of zeolites in chromatographic columns for sugar separation [11], type BEA zeolites have shown a high selectivity between different carbohydrates [12] and have already been used to capture the disaccharide isomaltose in enzymatic reactions [13][14][15][16]. Moreover, commercially available BEA 150 zeolite extrudates have shown advantageous adsorption isotherms for the separation of laminaribiose against fructose and glucose as needed here [17,18] whereas sucrose adsorbs even weaker than the solvent water [19].…”

“…Moreover, commercially available BEA 150 zeolite extrudates have shown advantageous adsorption isotherms for the separation of laminaribiose against fructose and glucose as needed here [17,18] whereas sucrose adsorbs even weaker than the solvent water [19]. Successful combination of enzymatic production and adsorption with subsequent downstream processing has only been shown for a monoenzymatic production system where enzymatic catalysis and adsorption were integrated in a set-up comprising of fluidized bed of biocatalysts and a slurry of zeolite particles [16,20]. In here, a bienzymatic production of laminaribiose is combined with adsorption in a system comprising of two solid phases (biocatalyst pearls and zeolite particles) and one fluid phase of reaction solution implemented in two consecutive fixed beds.…”