scholarly journals Fabrication of gelatin microspheres containing ammonium hydrogen carbonate for the tunable release of herbicide

Author(s):  
He Liu ◽  
Zheng Zhang ◽  
Jiaxin Li ◽  
Wanyu Zang ◽  
Qing Yang ◽  
...  
2021 ◽  
Author(s):  
He Liu ◽  
Zheng Zhang ◽  
jun yang ◽  
Wanyu Zang ◽  
Qing Yang

Abstract The major challenge in utilizing pesticides lies in identifying the precise application that would improve the efficiency of these pesticides and reduce their environmental and health hazards at the same time. Such application requires the development of specific formulations that enable controlled, stimuli-responsive release of the pesticides. Gelatin is a relatively cheap material characterized by temperature-sensitivity and abundant amino acid groups, which makes it suitable for the storage and controlled release of pesticides. In this study, gelatin microspheres were prepared by emulsion and cross-linking, then they were loaded with 2,4-dichlorophenoxyacetic acid sodium (2,4-D Na) as a model herbicide. To achieve temperature-tunable release of 2,4-D Na from the microspheres, NH4HCO3 was added to the formulations at different concentrations. The prepared formulations were characterized by SEM, FTIR, and size distribution analyses, and their drug loading capacities were determined. Based on bioassay experiments, the 2,4-D Na-NH4HCO3-loaded gelatin microspheres can effectively control the spread of dicotyledonous weeds. Therefore, the strategy proposed herein can be used to develop novel, effective herbicide formulations.


2000 ◽  
Vol 15 (9) ◽  
pp. 1864-1867 ◽  
Author(s):  
Ji Guang Li ◽  
Takayasu Ikegami ◽  
Jong-Heun Lee ◽  
Toshiyuki Mori ◽  
Yoshiyuki Yajima

Ammonium hydrogen carbonate was used as the precipitant to synthesize yttrium aluminate garnet (YAG) precursors from a mixed solution of aluminum and yttrium nitrates via coprecipitation. The carbonate precursor, with an approximate composition of NH4AlY0.6(CO3)1.9(OH)2 · 0.8H2O, transformed to pure YAG at 900 °C without the formation of intermediate phases. Reactive YAG powder was produced by calcining the precursor at 1100 °C. The YAG powder densified to 99.8% of the theoretical density by vacuum sintering at 1500 °C for 2 h, and the sintered body showed transparency. Less agglomeration of the precursor and good dispersity of the resultant YAG powder were responsible for the excellent sinterability.


2007 ◽  
Vol 7 (11) ◽  
pp. 3906-3909
Author(s):  
Sang Woo Kim ◽  
Young Mi Jung

We have suggested ultrafine particle coating processes for preparing nanocrystalline particle coated α-alumina powders by a carbonate precipitation and thermal-assisted combustion route, which is environmentally friendly. The nanometric ammonium aluminum carbonate hydroxide (AACH) as a precursor for coating of alumina was produced from precipitation reaction of ammonium aluminum sulfate and ammonium hydrogen carbonate. The synthetic crystalline size and morphology were greatly dependent on pH and temperature. By adding ammonium aluminum sulfate solution dispersed the α-alumina core particle in the ammonium hydrogen carbonate aqueous solution, nanometric AACHwith a size of 5 nm was tightly bonded and uniformly coated on the core powder due to formation of surface complexes by the adsorption of carbonates, hydroxyl and ammonia groups on the surface of aluminum oxide. The synthetic precursor rapidly converted to amorphous- and γ-alumina phase without significant change in the morphological features through decomposition of surface complexes and thermal-assisted phase transformation. As a result, the nanocrystalline polymorphic particle coated α-alumina core powders with highly uniform distribution were prepared from the route of carbonate precipitation and thermal-assisted combustion.


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