Adsorption and Desorption Behavior of Ectoine Using Dowex(R) HCR-S Ion-Exchange Resin

Dowex(R) HCR-S ion-exchange resin was used to adsorb ectoine in a batch system under varying operation conditions in terms of contact time, temperature, pH value, initial concentration of ectoine, and type of salt. Six adsorption isotherm models (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Sips, and Redlich-Peterson) and three kinetic models (pseudo-first-order, pseudo-second-order, and intraparticle diffusion) were used to investigate the ectoine adsorption mechanism of ion-exchange resin. According to the experimental results, the mechanism of ectoine adsorption using an ion exchanger includes the ion-exchange reaction and physisorption. Both the Langmuir and Freundlich models were found to have a high fitting. For the kinetic analysis, the pseudo-second-order and intraparticle diffusion models were suitable to describe the ectoine adsorption. Dowex(R) HCR-S resin has an average saturated adsorption capacity of 0.57 g/g and 93.6% of ectoine adsorption at 25 similar to 65 & DEG;C, with an initial concentration of 125 g/L. By changing the pH of the environment using NaOH solution, the adsorbed ectoine on the ion-exchange resin can be desorbed to 87.7%.

Automated summary

The study investigated the mechanism of ectoine adsorption using Dowex(R) HCR-S ion-exchange resin, finding that it involves ion-exchange reaction and physisorption. Experimental results showed that the Langmuir and Freundlich models fit the adsorption process well, while the pseudo-second-order and intraparticle diffusion models are suitable for describing the adsorption kinetics.