Selective adsorption and special recognition of roxarsone (ROX) from water by utilizing novel core-shell magnetic molecularly imprinted polymers

Abstract

To eliminate environmental risk that induced from organoarsenic feed additive ROX, and enhance special selectivity and recognizability of this micro-polluted aromatic organoarsenicals compound in complex aqueous as well. Novel core-shell magnetic molecularly imprinted polymers (MMIPs) were successfully synthesized through the surface imprinting technology, which circumvented the drawbacks of traditional method such as the deep embedding of the imprinting sites and incomplete elution of the target molecule. Owing to its imprinting effect, the obtained MMIPs displayed excellent behavior and performance for ROX removal compared with magnetic non-imprinted polymers (MNIPs), the binding isotherms of ROX for both MMIPs and MNIPs were better fitted by Langmuir model, and two types of binding sites (specific and non-specific adsorption sites) existed on the surface of MMIPs. The removal efficiency of ROX by MMIPs remained unchanged along with a broad pH range (3.0–10.0), whereas pH seriously affected the ROX removal efficiency of MNIPs. The better uptake of ROX by MMIPs co-existed with competitive substances and two other organic/inorganic arsenic compounds (p-ASA/As(V)) confirmed the high binding selectivity and special recognizability for its target pollutant. Finally, the application in different spiked real water samples and continuous flow tests further demonstrated MMIPs were the promising candidates and of the potential application future to selectively remove this trace pollutant in different water bodies.