Issue 32, 2018, Issue in Progress

Modified iron phosphate/polyvinyl alcohol composite film for controlled-release fertilisers

Abstract

Traditional soluble phosphorous (P) fertilisers can be easily leached to pollute water systems, resulting in water eutrophication, a major environmental problem from the oversupply of unused nutrients. One innovative solution is to control the release of P upon demands of the plants. This study established a new concept of controlled-release P fertiliser via incorporation of ferric phosphate (FePO4) as a P source in polyvinyl alcohol (PVA) films, which can immobilise the FePO4 particles and stimuli-responsively accelerate their release rate in the presence of citric acid. More importantly, FePO4 used in this work originated from steelmaking slag as a potential waste reuse. Due to the low solubility of FePO4, diethylamine was introduced to modify FePO4 particles to facilitate the release of P before incorporating with PVA. The effects of diethylamine modification and the properties of FePO4/PVA films were systematically investigated through microscopic and spectroscopic methods. The release of P from particles and films was examined in both deionised water and citric acid solution for 30 days. The results showed a tenfold increase of the release rate of modified FePO4/PVA in citric acid solution compared with that in deionised water, and also a doubled release rate of the modified FePO4/PVA compared to that of FePO4/PVA in citric acid. The improved performance suggests that PVA can maintain the phosphorous content with exposure to water and expedite release in citric acid upon the demand of plants. This composite film offers a new opportunity for the application of insoluble phosphate as a phosphorous fertiliser.

Graphical abstract: Modified iron phosphate/polyvinyl alcohol composite film for controlled-release fertilisers

Supplementary files

Article information

Article type
Paper
Submitted
02 Mar 2018
Accepted
07 May 2018
First published
17 May 2018
This article is Open Access
Creative Commons BY license

RSC Adv., 2018,8, 18146-18152

Modified iron phosphate/polyvinyl alcohol composite film for controlled-release fertilisers

Y. Zhang, Z. Yi, L. Wei, L. Kong and L. Wang, RSC Adv., 2018, 8, 18146 DOI: 10.1039/C8RA01843J

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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