Urea-Hydroxyapatite Nanohybrids for Slow Release of Nitrogen

Abstract

While slow release of chemicals has been widely applied for drug delivery, little work has been done on using this general nanotechnology-based principle for delivering nutrients to crops. In developing countries, the cost of fertilizers can be significant and is often the limiting factor for food supply. Thus, it is important to develop technologies that minimize the cost of fertilizers through efficient and targeted delivery. Urea is a rich source of nitrogen and therefore a commonly used fertilizer. We focus our work on the synthesis of environmentally benign nanoparticles carrying urea as the crop nutrient that can be released in a programmed manner for use as a nanofertilizer. In this study, the high solubility of urea molecules has been reduced by incorporating it into a matrix of hydroxyapatite nanoparticles. Hydroxyapatite nanoparticles have been selected due to their excellent biocompatibility while acting as a rich phosphorus source. In addition, the high surface area offered by nanoparticles allows binding of a large amount of urea molecules. The method reported here is simple and scalable, allowing the synthesis of a urea-modified hydroxyapatite nanohybrid as fertilizer having a ratio of urea to hydroxyapatite of 6:1 by weight. Specifically, a nanohybrid suspension was synthesized by in situ coating of hydroxyapatite with urea at the nanoscale. In addition to the stabilization imparted due to the high surface area to volume ratio of the nanoparticles, supplementary stabilization leading to high loading of urea was provided by flash drying the suspension to obtain a solid nanohybrid. This nanohybrid with a nitrogen weight of 40% provides a platform for its slow release. Its potential application in agriculture to maintain yield and reduce the amount of urea used is demonstrated.

Synthesis and properties of Biostim protein filler based acrylic composites

“…Именно поэтому для фермеров и крупных компаний АПК одним из требований к используемым азотным удобрениям является пролонгированное действие веществ, сохранение влаги, регулируемая иммобилизация и доступность азота. Одним из путей решения поставленных задач является создание почвенного кондиционера, содержащего азотсодержащее органическое удобрение [4].…”

Slow Release Nanofertilizers for Bumper Crops

“…2,3 However, compared to controlled drug release for pharmaceutics, there has been a paucity of research on the agriculture applications of nanotechnology to improve release behavior of fertilizer formulations. Previous work has reported that carbon nanotubes can enter tomato seeds, and zinc oxide nanoparticles pass into rye grass root tissues.…”

“…9 Their method significantly reduces the amount of urea required for fertilization since it can be applied locally. Perhaps more impressively, the authors demonstrate that, with their approach, the rice crop yields are significantly enhanced even when 50% less urea is used.…”

“…Part of the figure is reproduced with permission from ref (9). Copyright 2017 American Chemical Society.…”

Breaking trade-off in nitrogen management and sustainability

“…Indeed, more stringent regulations for reactive nitrogen emissions and discharges in developed countries have been enforced to deter air and water pollutions, which reduce the amount of reactive nitrogen to the atmosphere and water bodies. From engineering standpoint, the application of nanotechnology to agricultural plants, named phytonanotechnology (Rajan et al 2015), would be promising to reduce the amount of fertilizes applied to a cropland (Kottegoda et al 2017). Developing a wastewater treatment system to mitigate N 2 O emission and to enhance nitrogen removal by harnessing novel microorganisms could be feasible.…”