Fabrication of phytic acid-modified wheat straw platform and its pH-responsive release performance for the pesticide imidacloprid

Abstract

For the effective utilization of pesticides and the treatment of abundant waste wheat straw (WS) resources, an eco-friendly composite PA-WS platform was prepared by modification of WS with phytic acid (PA). The structure and morphology of the synthesized products were characterized via SEM, FTIR, and zeta surface potential analyses. Elemental analysis and X-ray photoelectron spectroscopy (XPS) were used to determine the degree of substitution (DS) and degree of surface substitution (DSS). The evaluation of the release properties of PA-WS@IM showed that the release of imidacloprid (IM) molecules could be controlled via a pH-sensitive dynamic chemical bond. The release efficiency of IM was enhanced with a decrease in pH and the release efficiency achieved a maximum (85.29%) at pH 2. The release efficiency of IM in a solution of Ca²⁺ ions was higher than in the solution of Na⁺ ions, while Fe³⁺ ions aqueous solutions had no significant influence. Due to its controllable release, cost-effectiveness, reusability of a resource and eco-friendly preparation, it is believed that PA-WS@IM may have potential application in agriculture fields to enhance the utilization efficiency of pesticides and improve the comprehensive utilization of agriculture resources.