Biomineralization-inspired porous calcium carbonate microspheres as a controlled release system of herbicides/pesticides

Abstract

Low bioavailability and environmental pollution are the key problems that restrict the sustainable development of traditional herbicides and pesticides. In this study, inspired by biomineralization, we prepared porous calcium carbonate microspheres (PCMs) using polyvinylpyrrolidone (PVP) and carboxymethyl chitosan (CMCs) as particle size and morphology modifiers. PCMs have large specific surface area (87.6 m2/g) and mesoporous structure, which allows them to efficiently load herbicides (497±24 mg/g) and pesticides (318±17 mg/g). Additionally, the PCMs exhibit pH-responsive decomposition, enabling responsive release of glyphosate/chlorpyrifos in weak acid environments. In the simulation experiments, we found that the PCMs improved the adhesion ability of glyphosate/chlorpyrifos on the leaf surface and reduced the glyphosate/chlorpyrifos loss rate (1.69-fold reduction for glyphosate; 1.68-fold reduction for chlorpyrifos). Furthermore, glyphosate/chlorpyrifos loaded PCMs (GLY@PCMs/CPF@PCMS) exhibited herbicidal/insecticidal performance with the same efficacy as glyphosate/chlorpyrifos. Therefore, the PCMs provide an effective method for controlling herbicides/pesticides loss, controlled release of herbicides/pesticides, and improving herbicides/pesticides utilization efficiency. As a result, PCMs have the potential to be used as a pesticide/herbicide controlled release system, providing new ideas and theoretical support for the design of multifunctional nanoherbicides/nanopesticides in the future.