FeOOH imprinted nanorods based on boronate affinity surface imprinting for the separation of shikimic acid

Abstract

Up to now, extraction of shikimic acid (SA), precursor of antiviral drugs, from the surrounding plants is the most effective and sustainable method. However, it’s still a tough challenge to obtain high purity SA due to the complex components in the plant issue. In this study, based on the specific identification of boronate affinity, iron hydroxide oxide FeOOH with abundant functional groups was used as the substrate to prepare molecular imprinted polymers (FeOOH@MIPs) for selective recognition and adsorption of SA. Using 4-vinylphenylboronic acid (VPBA) as functional monomer, the imprinted polymers were prepared by the controllable directional surface imprinting method. FT-IR analysis and XPS study confirmed the characteristic structure and component of the products. From the results from the batch mode experiments, the maximum adsorption capacity of shikimic acid by FeOOH@MIPs can reach 42.919 mg g−1, which was enhanced compared with nonimprinted products. In addition, the adsorption process was well fitted with Langmuir isotherm model and pseudo-second-order model, implying the chemisorption of SA onto FeOOH@MIPs through the monolayer. The investigation on pH factor showed that the adsorption amount towards SA increased and then declined with the increase of pH value in the surrounding solution, attributing to the feature of boronate affinity effect. More importantly, it was found that the adsorbent exhibited competitive reusability performance. FeOOH@MIPs maintained 86.45% of the first cycle adsorption capacity towards SA after 5 cycles, giving a reasonable proof for the feasible application of the products in the separation of substances containing the special structure of cis-diol.