A Pitaya-Inspired Modular Cylindrical MOF-Based Capsule Design for Pesticide Signal Probes

Excessive
use of pesticides has brought about serious
environmental
risks worldwide that pose significant harm for human health. Herein,
a series of metal–organic framework (MOF)-based gel capsules
with a pitaya-like core–shell structure are constructed through
a green polymerization strategy for pesticide detection and removal,
namely ZIF-8/M-dbia/SA (M = Zn, Cd). Significantly, the ZIF-8/Zn-dbia/SA capsule exhibits sensitive detection of alachlor,
a representative pre-emergence acetanilide pesticide, with a satisfactory
detection limit of 0.23 μM. In addition, the MOF-based gel capsules
can be extended to a universal visual platform for the noninvasive
detection of pesticide residues with various MOFs, such as Eu-MOF,
Tb-MOF, and Cu-MOF, and participating dye. Similar to pitaya, the
ordered porous structure of MOF in ZIF-8/Zn-dbia/SA capsules
offers cavity and open sites for removing pesticide from water with
the maximum adsorption amount qmax of
61.1 mg·g–1 toward alachlor in a Langmuir model.
Thereby, this work presents the universality of gel capsule self-assembly
technologies, including the well-preserved visible fluorescence area
and porosity of the different structurally diverse MOFs, offering
an ideal strategy for water decontamination and food safety control
fields.