# Intercalation of Glyphosate in Mg–Al Layered Double Hydroxides and Its Controlled Release

## TL;DR

This paper explores how glyphosate can be intercalated into Mg–Al layered double hydroxides and how its release can be controlled under different conditions.

## Contribution

The study introduces a method for creating Mg–Al LDH hybrids with glyphosate and demonstrates controlled release mechanisms influenced by pH and anions.

## Key findings

- Mg2Al–glyphosate hybrid materials were successfully synthesized with better crystallinity via coprecipitation.
- Glyphosate release was highest at pH 10, reaching about 70%, and followed first-order kinetics.
- Carbonate anions significantly enhanced glyphosate release, with higher concentrations leading to greater release.

## Abstract

The LDHs in the Mg–Al systems containing glyphosate
were
synthesized by the reconstruction and coprecipitation methods at a
constant pH. The XRD data show that the Mg2Al–glyphosate
hybrid material was formed in both cases, even though a better crystallinity
was achieved from the synthesis conducted by the coprecipitation method.
Moreover, vertical glyphosate intercalation can be inferred, given
the observed 7.9 Å interlamellar spacing. Solid-state NMR and
FT-IR-ATR data corroborate the formation of the material, with significant
changes in the spectra of both when comparing the hybrid materials
and free glyphosate. Studies involving pH variation showed the greatest
glyphosate release at pH 10, reaching approximately 70% and governed
by first-order kinetics, confirmed by the simulation model. Experiments
involving carbonate, nitrate, and chloride anions suggest that the
presence of carbonate has a greater influence on glyphosate release
and that an increase in the concentration of this anion also corroborates
to an increase in glyphosate release, both of which are also governed
by a first-order mechanism.