Study on the adsorption behavior of chlorogenic acid from Eucommia ulmoides Oliver leaf extract by a self-synthesized resin

Chlorogenic acid (CGA) has various biological activities and is widely existed in plants. In this work, the GMA-10 resin modified by glycidyl methacrylate was prepared to investigate the adsorption behaviors toward CGA. N2 adsorption-desorption isotherms, SEM, FT-IR spectroscopy were used to characterize structural changes of GMA-10 before and after adsorption. The adsorption performance of GMA-10 and other resins (Amberlite 732, ST-DVB, AB-8, and X-5) were compared under different initial pH value, adsorbent dosage, chlorogenic acid concentration, and desorbent concentration by static adsorption experiments. Dynamic adsorption and desorption experiments showed a 5.12-folds increase in chlorogenic acid content from 7.37% to 37.78% with a recovery of 84.91% after treatment with GMA-10 resin. Reusability experiments showed the decrease of adsorption capacity was under 1.78% in 5 cycles. In addition, adsorption isotherms revealed that the adsorption conformed to Langmuir model. Adsorption kinetics studies showed that the pseudo-second-order model accurately described the adsorption process, and both intra-particle diffusion and liquid film diffusion together limited the mass transfer rate. In summary, these results show the potential of GMA-10 to separate and purify CGA from Eucommia ulmoides Oliver leaf.