Adsorptive recovery of geniposidic acid from gardenia yellow pigment extraction wastewater by anion exchange: equilibrium, thermodynamics and mechanism modeling and simulation

For many years, the traditional process of gardenia yellow pigment extraction has produced wastewater containing significant quantities of Geniposidic acid (GSA), a substance that could be put to pharmacological uses if it could be effectively recovered. This study aimed to provide an efficient adsorption material, D08, for recycling GSA. Batch experiments showed that adsorption capacity depends on initial concentration and temperature. The maximal adsorption capacity of GSA onto an anionic exchanger reached 310 mg/g. The p K a value of GSA was determined to be 4.21. Pore diffusion coefficients ( D p ) of GSA for 283, 298 and 313 K were 3.274 × 10 −10 , 5.069 × 10 −10 and 7.356 × 10 −10 m 2 /s, respectively. Recovery efficiency of GSA was achieved to 99.81 %. In comparison with pseudo first-order and pseudo second-order equations, the PDM model demonstrated the best fit to the kinetics data of GSA adsorption. Adsorption/desorption experiments proved that D08 offers great adsorption capacity, high adsorption rate and good repeatability. In order to help us to accurately comprehend the mass transfer process, numerical simulation and post-processing to variables c ( r , t ) and q ( r , t ) were performed to clarify the adsorption process.