Plant nutrient coated nanoparticles and methods for their preparation and use

1. A nanofertilizer comprising a metal nanoparticle coated with boric acid, wherein the metal nanoparticle is selected from the group consisting of gold, copper, aluminum, nickel, chromium, iron, cobalt, tin, titanium, zinc, lead, platinum, palladium, rhodium, tantalum, ruthenium, tungsten, an alloy thereof, and a combination thereof, wherein the boric acid is present in an amount of about 0.001 ppm to about 2.0 ppm of the nanofertilizer, and is sufficient to increase boron content in a plant.

2. The nanofertilizer of claim 1 , wherein ratio of boric acid to metal is from about 1:2 to about 2:1 w/w.

3. The nanofertilizer of claim 1 , wherein size of the metal nanoparticle is in a range of 10-1000 nanometers.

4. The nanofertilizer of claim 1 , wherein the nanofertilizer is in an aqueous solution.

5. A nanofertilizer comprising at least one plant nutrient coated on a metal nanoparticle, wherein the at least one plant nutrient is selected from the group consisting of potassium nitrate, calcium nitrate, magnesium nitrate, ammonium phosphate, magnesium sulfate, potassium phosphate, calcium carbonate, ammonium nitrate sulfate, ammonium thiosulfate, aqua ammonia, urea, sodium nitrate, potassium carbonate, potassium chloride, potassium magnesium sulfate, potassium metaphosphate, zinc phosphate, zinc ammonium phosphate, zinc sulfate, manganese sulfate, manganese ammonium phosphate, ferrous ammonium sulfate, ferrous ammonium phosphate, cupric ammonium phosphate, copper sulfate, ammonium molybdate, sodium molybdate, molybdenum sulfide, and a combination thereof, wherein the at least one plant nutrient is present in an amount of about 0.001 ppm to about 2.0 ppm of the of nanofertilizer, and is sufficient to increase content of the at least one plant nutrient in a plant.

6. The nanofertilizer of claim 5 , wherein the metal nanoparticle is selected from the group consisting of gold, silver, copper, aluminum, nickel, chromium, iron, cobalt, tin, titanium, zinc, lead, platinum, palladium, rhodium, tantalum, ruthenium, tungsten, an alloy thereof, and a combination thereof.

7. The nanofertilizer of claim 5 , wherein size of the metal nanoparticle is in a range of 10-1000 nanometers.

8. The nanofertilizer of claim 5 , wherein the nanofertilizer is in an aqueous solution.

9. A method of making a nanofertilizer comprising a metal nanoparticle coated with a plant nutrient, the method comprising: providing a metal nanoparticle; and coating the metal nanoparticle with at least one plant nutrient or precursor thereof, wherein the at least one plant nutrient is present on the metal nanoparticle in an amount of about 0.001 ppm to about 2.0 ppm of nanofertilizer and is sufficient to increase content of the at least one plant nutrient in a plant, and wherein the at least one plant nutrient is selected from the group consisting of boric acid, potassium nitrate, calcium nitrate, magnesium nitrate, ammonium phosphate, magnesium sulfate, potassium phosphate, calcium carbonate, ammonium nitrate sulfate, ammonium thiosulfate, a qua ammonia, urea, sodium nitrate, potassium carbonate, potassium chloride, potassium magnesium sulfate, potassium metaphosphate, zinc phosphate, zinc ammonium phosphate, zinc sulfate, manganese sulfate, manganese ammonium phosphate, ferrous ammonium sulfate, ferrous ammonium phosphate, cupric ammonium phosphate, copper sulfate, ammonium molybdate, sodium molybdate, molybdenum sulfide, and a combination thereof.

10. The method of claim 9 , wherein providing the metal nanoparticle comprises providing the metal nanoparticle selected from the group consisting of gold, silver, copper, aluminum, nickel, chromium, iron, cobalt, tin, titanium, silicon, zinc, lead, platinum, palladium, rhodium, tantalum, ruthenium, tungsten, an alloy thereof, or a combination thereof.

11. The method of claim 9 , wherein providing the metal nanoparticle comprises forming the metal nanoparticle through salt reduction synthesis, reverse micelles process, microwave dielectric heating reduction, ultrasonic irradiation, radiolysis, solvothermal synthesis, bioreduction, heat evaporation, photochemical reduction, electrochemical synthesis, or a combination thereof.

12. The method of claim 9 , wherein coating the metal nanoparticle with the at least one plant nutrient or precursor thereof comprises: mixing the metal nanoparticle and the at least one plant nutrient in an aqueous medium to form a solution; and adding a reducing agent to the solution to form the coated metal nanoparticle.

13. The method of claim 12 , wherein mixing the metal nanoparticle and the plant nutrient in the aqueous medium to form the solution comprises heating the solution at a temperature of a bout 70° C. to a bout 110° C.

14. The method of claim 12 , wherein adding the reducing agent to the solution comprises adding the reducing agent selected from the group consisting of sodium citrate, sodium borohydride, hydroquinone, glycol ethylene, formaldehyde, ethanol, hydroxyl radicals, sugar pyrolysis radicals, hydrazine hydrate, saccharide, N,N-dimethylformamide, and a combination thereof, to the solution.

15. The method of claim 12 , wherein adding the reducing agent to the solution comprises heating the solution at a temperature of about 70° C. to about 110° C.

16. The method of claim 12 , further comprising adding a stabilizer to the solution after adding the reducing agent.

17. The method of claim 16 , wherein adding the stabilizer comprises adding the stabilizer selected from the group consisting of polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose, poly(vinylpyrrolidone), sodium dodecyl sulphate, long-chain thiol, long-chain amines, carboxylic compounds, bovine serum albumin, cellulose, and a combination thereof, to the solution.

18. The method of claim 16 , further comprising mixing the solution to allow the temperature of the solution to decrease to room temperature.