Investigation of slow release of urea from biodegradable single- and double-layered hollow nanofibre yarns

Leila Javazmi,Anthony Young,Tobias Low,Gavin Ash

doi:10.1038/s41598-020-76395-6

Leila Javazmi, Anthony Young + Show 2 more

Open Access

https://doi.org/10.1038/s41598-020-76395-6

Copy DOI

Abstract

Urea is the most common form of nitrogenous fertiliser. Recently, research has focused on the development of delivery systems to prolong fertiliser release and prevent fertiliser loss through leaching and volatilization. This study investigates and compares single- and double-layered hollow nanofibrous yarns as novel delivery systems to encapsulate and release urea. Single-layered hollow poly l-lactic acid (PLLA) nanofibre yarns loaded with urea fertiliser were fabricated using a customized electrospinning. Double-layered hollow nanofibre yarns were produced by electrospinning polyhydroxybutyrate (PHB) nanofibres as an outer layer, with urea-impregnated PLLA nanofibres as the inner layer. Scanning electron microscopy (SEM) with an energy-dispersive spectroscopy (EDS) was used to characterize the morphology of hollow electrospun nanofibre yarns. A total nitrogen instrument (TNM-1) was used to study the urea release from single- and double-layered hollow nanofibres yarn in water. A Carbon:Nitrogen (CN) elemental analyser determined encapsulated nitrogen in PLLA nanofibres samples. Results indicated that urea-impregnated double-layered hollow nanofibre yarns significantly started nitrogen releasing at much lower amount during first 12 h compared to single-layered hollow nanofibre yarns (P value = 0.000). In conclusion, double-layered hollow nanofibre yarn has potential as an effective alternative to current methods for the slow release of fertilisers and other plant-required chemicals.

Highlights

Urea is the most common form of nitrogenous fertiliser
The decrease in the diameter of the core space is due to placement of coresheath nanofibre yarn in boiling water for one minute to dissolve the polyvinyl alcohol (PVA) nanofibres that led to lateral shrinkage of the hollow nanofibre yarn
The energy-dispersive spectroscopy (EDS) shows the amount of nitrogen element in spectrum 11 based on (w/w) % to poly l-lactic acid (PLLA) mass amount

Summary

Introduction

Urea is the most common form of nitrogenous fertiliser. Recently, research has focused on the development of delivery systems to prolong fertiliser release and prevent fertiliser loss through leaching and volatilization. This study investigates and compares single- and double-layered hollow nanofibrous yarns as novel delivery systems to encapsulate and release urea. Double-layered hollow nanofibre yarn has potential as an effective alternative to current methods for the slow release of fertilisers and other plant-required chemicals. As a neutral organic molecule, urea is not readily absorbed by charged soil particles and can volatilize before hydrolysis is achieved[2] This results in only a fraction of applied urea nitrogen being absorbed by plants, which may result in large quantities of urea being lost in agricultural runoff, contributing to groundwater p ollution[3]. The advent of composite hollow nanostructures adds a new dimension to nanofibre applications These have extended the impact of particles by coupling their functionality with the feasible processability of synthetic polymers[9]. The use of nanofibres to encapsulate agrichemicals may allow different chemical additives to be used together through separate nanofibres, and can prolong agricultural additive release by several months[4,5,11,12,13]

Objectives

Methods

Results

Conclusion