Flow Synthesis of Phosphorus Nanocomposites for Controlled Fertilizer Release and Wheat Growth
Volker Hessel,
Professor,
The University of Adelaide
Flow chemistry has shown distinct advantages in the synthesis of
nanomaterials. Here, we investigate flow chemistry for the synthesis of
nanofertilizers which has been so far less reported in literature. New
generations of P fertilizer have been developed in batch synthesis. In
2020, Hessel et al. proposed a process for leaching phosphorus from
mimicked moon crust using a re-entrance flow microfluidic device and
using this to fertilize lettuce in “space greenhouses”, and recycling
phosphate from lettuce root via burning in a furnace.
In this
research, a coiled inverted flow system, was used to prepare a slow
released P-containing fertilizer and this system also allowed the direct
adsorption of low molecular weight organic acid anions (LMWOAs).
Citrate ions, as the chosen LMWOAs, were incorporated with the above
prepared phosphorus fertiliser to form a compound fertilizer capable of
releasing nutrients in a slow manner and reducing the P binding sites in
P deficient soil. The nutrient performance was investigated in a model
soil mixture. The system allowed the one-stage production of LMWOAs
adsorbed apatite with the maximum adsorption capacity of 0.19
gcitrate.gaptite-1 in a continuous manner. The presence of citrate ions
in the prepared material increased the P availability in the model soil
mixture by 2.6 times compared to commercial apatite. After 14 days of
application, about 57% of P in the prepared fertilizer was released into
the soil solution.
We will also report about an extension of
the approach here towards nanoencapsulation by chitosan and using more
innovative continuous-flow reactor equipment, including the Corning and
StoliFlow reactors. We will compare the wheat growth efficiency of the
flow-made phosphorus nanofertilizers with plasma-made nitrogen (carbon
dot and solution-based) fertilizers, which we also prepare.
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