The Role of Cellulose Charge and Matrix Composition on KNO3‑Nutrient Release Kinetics and Mechanisms

TL;DR

This study explores how the structure and charge of a cellulose-based matrix affect the release of potassium and nitrate nutrients from fertilizers, aiming to improve fertilizer efficiency and sustainability.

Contribution

The study identifies how matrix composition and cellulose charge influence nutrient release mechanisms, offering insights for optimizing enhanced efficiency fertilizers.

Findings

The Korsmeyer-Peppas and Peppas-Sahlin models best describe the anomalous release behavior of nutrients.

Positively charged CNF promotes K+ release via diffusion and NO3– via matrix relaxation.

Negatively charged CNF results in K+ release via matrix relaxation and NO3– via diffusion.

Abstract

The global demand
for food is driving research into regenerative
agriculture, particularly the development of enhanced efficiency fertilizers
(EEFs) that aim to improve nutrient use efficiency and reduce environmental
impact. Understanding the release mechanisms of EEFs is essential
for designing more effective formulations. This study examines the
nutrient release kinetics of EEFs, focusing on potassium nitrate (KNO3) embedded in a cellulose-based matrix produced via spray-drying
and melt-processing. Several mathematical models – Zero-order,
First-order, Higuchi, Korsmeyer-Peppas, Peppas-Sahlin, Hixson-Crowell,
and Hopfenberg – were used to analyze nutrient release dynamics
in water. The results showed that the matrix structure, particle formation
method, and CNF charge influence the release mechanism. The Korsmeyer-Peppas
and Peppas-Sahlin models best described the anomalous release behavior.
K+ release is primarily driven by diffusion, and NO3
– release is governed by matrix relaxation
when combined with positively charged CNF (CNF+). In contrast,
K+ is released via matrix relaxation and NO3
– via diffusion when combined with negatively charged
CNF (CNF–). Adjusting CNF charge or matrix composition
can optimize nutrient release, improve fertilizer management, and
enhance sustainability in agricultural practices.

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