Central composite design optimized adsorptive removal of cis,cis-muconic acid by weak basic anion exchangers and activated Carbon

cis,cis-Muconic acid is a high value-added fermentation product, which is used as a precursor for the synthesis of commercially important bulk chemicals. Therefore, its recovery from the fermentation broth is essential. In this study, the adsorptive removal of cis,cis-muconic acid has been examined for the first time. cis,cis-Muconic acid has been removed from its aqueous solution by Amberlite IRA-67, Amberlite XAD-4, Amberlite A-21, and activated carbon. The adsorption kinetic behavior of cis,cis-Muconic acid has been examined by kinetic models and best described by pseudo-second-order model. The distribution of the acid onto the adsorbents has been investigated by several two-parameter isotherm models. All the adsorbents were found to be quite successful at removing the acid because adsorption capacities reached up to 99 mg g(-1) in a short time interval. After the kinetic study, it is revealed that 20 min of shaking was appropriate to remove the acid. The Biot numbers less than 100 indicated that external diffusion occurred predominantly on the adsorbent surface instead of internal diffusion. Central composite design of response surface methodology was used to optimize the important adsorption parameters, namely, acid concentration, adsorbent quantity, and temperature. The model predicted best results at 994.70 mg L-1 acid concentration, 0.08 g adsorbent quantity, and 300.2 K temperature for IRA-67; 994.70 mg L-1 acid concentration, 0.05 g adsorbent quantity, and 301.2 K temperature for XAD-4; 994.70 mg L-1 acid concentration, 0.08 g adsorbent quantity, and 300.2 K temperature for A-21; and 994.70 mg L-1 acid concentration, 0.08 g adsorbent quantity, and 299.2 K temperature for activated carbon.