Concentrated aqueous suspension of microfibrillated cellulose comprising salts for plant nutrition

Abstract

A concentrated aqueous suspension of microfibrillated cellulose (MFC) comprising salts for plant nutrition, the concentrated aqueous suspension comprises microfibrillated linear polymers of D-glucose molecules homogenized through a fibrillation process (cellulose microfibers), calcium ions, sulfate ions and other substances for plant nutrition, being the concentration of calcium ions and sulfate ions in excess of the concentration corresponding to the solubility of calcium sulfate in water and being the proportion of microfibrillated cellulose (MFC) within a range of 1% and 99% w/w of the suspension.

Claims

1. A concentrated aqueous suspension for plant nutrition comprising (w/w): between 0.5% and 99% of water; between 1% and 40% of microfibrillated cellulose (MFC); between 0.1% and 55% of calcium nitrate; between 0.01% and 0.5% of magnesium EDTA; between 0.01% and 0.7% of manganese EDTA; between 0.01% and 0.7% of zinc EDTA; between 0.01% and 0.9% iron EDTA; between 0.01% and 0.1% of copper EDTA; between 0.001% and 0.01% sodium molybdate (Dihydrate); between 0.0001% and 0.001% of cobalt EDTA; between 0.01% and 0.4% of boric acid; between 1% and 12% of potassium nitrate; between 0.5% and 25% of monopotassium phosphate; between 0.5% and 42% of magnesium sulfate; and between 0.1% and 11% of potassium sulfate, wherein the calcium ions and sulfate ions have a concentration in excess of the concentration corresponding to the solubility of calcium sulfate in water, and wherein the percipitation of salts is prevented in a pH range of 1 to 13.

2. The concentrated aqueous suspension for plant nutrition according to claim 1, further comprises: 18.6 liters of water (68.2% w/w); 6,000 grams of microfibrillated cellulose (22.0% w/w); 1,000 grams of calcium nitrate (3.7% w/w); 12 grams of magnesium EDTA (0.0440% w/w); 20 grams of manganese EDTA (0.0733% w/w); 20 grams of zinc EDTA (0.0733% w/w); 25 grams of iron EDTA (0.0916% w/w); 3 grams of copper EDTA (0.0110% w/w); 0.3 grams of Sodium molybdate (Dihydrate) (0.0011% w/w); 0.03 grams of cobalt EDTA (0.0001% w/w); 10 grams of boric acid (0.0366% w/w); 300 grams of potassium nitrate (1.10% w/w); 400 grams of monopotassium phosphate (1.47% w/w); 750 grams of magnesium sulfate (2.75% w/w); 150 grams of potassium sulfate (0.55% w/w).

3. The concentrated aqueous suspension for plant nutrition according to claim 1, further comprising (w/w): between 1% and 5% of potassium nitrate, between 5% and 10% of monopotassium phosphate, between 8% and 15% of magnesium sulfate, and between 15% and 20% of calcium nitrate.

4. The concentrated aqueous suspension for plant nutrition according to claim 1, further comprising (w/w): between 5% and 10% of potassium nitrate, between 1% and 7% of monopotassium phosphate, between 5% and 10% of magnesium sulfate, between 5% and 15% of calcium nitrate, and between 0.1% and 3% of potassium sulfate.

5. The concentrated aqueous suspension for plant nutrition according to claim 1, furthr comprising (w/w): between 5% and 10% of potassium nitrate, p1 between 1% and 7% of monopotassium phosphate, between 5% and 15% of magnesium sulfate, and between 1% and 5% of calcium nitrate.

6. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 5% and 10% of monopotassium phosphate, p1 between 15% and 25% of magnesium sulfate, and between 5% and 15% of calcium nitrate.

7. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 10% and 12% of potassium nitrate, between 5% and 10% of monopotassium phosphate, p1 between 15% and 25% of magnesium sulfate, between 25% and 35% of calcium sulfate, and between 1% and 3% of potassium sulfate.

8. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 5% and 10% of potassium nitrate, between 5% and 10% of monopotassium phosphate, p1 between 5% and 15% of magnesium sulfate, and between 20% and 30% of calcium nitrate.

9. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 5% and 10% of potassium nitrate, between 1% and 7% of monopotassium phosphate, p1 between 5% and 15% of magnesium sulfate, and between 25% and 35% of calcium nitrate.

10. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 1% and 5% of potassium nitrate, between 1% and 7% of monopotassium phosphate, p1 between 1% and 7% of magnesium sulfate, and between 5% and 15% of calcium nitrate.

11. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 10% and 12% of potassium nitrate, between 1% and 7% of monopotassium phosphate, p1 between 1% and 7% of magnesium sulfate, and between 25% and 35% of calcium nitrate.

12. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 10% and 12% of potassium nitrate, between 1% and 7% of monopotassium phosphate, p1 between 1% and 7% of magnesium sulfate, and between 5% and 15% of calcium nitrate.

13. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 1% and 5% of potassium nitrate, between 1% and 7% of monopotassium phosphate, p1 between 5% and 15% of magnesium sulfate, and between 30% and 40% of calcium nitrate.

14. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 5% and 15% of calcium nitrate; between 35% and 42% of magnesium sulfate; p1 between 10% and 12% of potassium nitrate; and between 1% and 7% of monopotassium phosphate.

15. The concentrated aqueoous suspension for plant nutrition according to claim 1, further comprising (w/w): between 5% and 15% of magnesium sulfate; between 10% and 20% of monopotassium phosphate, p1 between 5% and 15% of calcium nitrate, and between 5% and 10% of potassium nitrate.

16. The concentrated aqueous suspension for plant nutrition according to claim 1, wherein the suspension comprises between 60% and 90% of water.

17. The concentrated aqueous suspension for plant nutrition according to claim 1, wherein the suspension comprises between 0.5% and 90% of water and between 1% and 22% of MFC.

Description

DESCRIPTION OF SPECIFIC EMBODIMENT OF THE INVENTION

(1) The formulations for fertilizers vary according to the specific requirements of each crop, its stage of development and the surrounding climatic conditions.

(2) The salts that are most commonly used for the formulation of stock A are as follows: Calcium nitrate Potassium nitrate (optional, since it is also present in stock B) Ammonium nitrate Iron ethylenediamine tetraacetic acid (Fe EDTA) Sodium molybdate (dihydrate) Ethylenediamine tetraacetic manganese (Mn EDTA) Ethylenediamine tetraacetic zinc (Zn EDTA) Ethylenediamine tetraacetic magnesium (Mg EDTA) Ethylenediamine tetraacetic copper (Cu EDTA) Ethylenediamine tetraacetic cobalt (Co EDTA) Boric acid

(3) The most common salts to formulate stock B are: Potassium sulfate Magnesium sulfate Monopotassium phosphate Potassium nitrate

(4) As described above, stock A usually includes the nitrates (calcium, potassium and ammonium) and the EDTA-chelated microelements. However, another possible common formulation is to incorporate only the nitrates (calcium, potassium and ammonium) and the iron EDTA in stock A; and to incorporate the microelements in the form of sulfates (magnesium, manganese, copper, zinc, etc.) in stock B, so that sulfates and calcium do not precipitate as calcium sulfate.

(5) Surprisingly, applicants of the present patent application found another alternative which involves the use of microfibrillated cellulose (MFC), obtained from a fibrillation process of cellulose in wet state.

(6) Microfibrillated cellulose (MFC) is a substance composed of cellulose and water, with a cellulose concentration of less than 15%. It is characterized by being able to store large quantities of water in relation to its mass, obtaining “creamy” or “gel-type” suspensions with very low proportions of microfibrillated cellulose (as low as 2%). Its pH varies in a range from 4 to 8 and its density between 1.2 and 1.6 kg/L.

(7) Cellulose microfibrils are very small cellulose fibers obtained from the mechanical disintegration of plant fibers and by a sequence of specific chemical and mechanical treatments (fibrillation process).

(8) When the cellulose goes through a fibrillation process, the surface area becomes much larger in comparison with the original raw material, thus generating a significant increase in the quantity of hydroxyl groups (OH) available on the surface of the microfibrils. As this hydroxyl groups have a natural negative charge, they will be able to capture ions with positive charge, such as calcium ions. In this way, the calcium ions are prevented from bonding with the sulfates, avoiding altogether its precipitation as calcium sulfate.

(9) A preferred aqueous suspension of the present invention involves:

(10) All percentages in the following description and in the examples correspond to % w/w

(11) Between 60% and 90% of water

(12) Between 1% and 40% of microfibrillated cellulose (MFC)

(13) Between 1% and 55% of calcium nitrate

(14) Between 0.01% and 0.5% of magnesium EDTA

(15) Between 0.01% and 0.7% of manganese EDTA

(16) Between 0.01% and 0.7% of zinc EDTA

(17) Between 0.01% and 0.9% iron EDTA

(18) Between 0.01% and 0.1% of copper EDTA

(19) Between 0.001% and 0.01% sodium molybdate (Dihydrate)

(20) Between 0.0001% and 0.001% of cobalt EDTA

(21) Between 0.01% and 0.4% of boric acid

(22) Between 1% and 12% of potassium nitrate

(23) Between 0.5% and 25% of monopotassium phosphate

(24) Between 0.5% and 42% of magnesium sulfate

(25) Between 0.1% and 11% of potassium sulfate

(26) A most preferred aqueous suspension of the present invention involves:

(27) 18.6 liters of water (68.2%)

(28) 6,000 grams of microfibrillated cellulose (22.0%)

(29) 1,000 grams of calcium nitrate (3.7%)

(30) 12 grams of magnesium EDTA (0.0440%)

(31) 20 grams of manganese EDTA (0.0733%)

(32) 20 grams of zinc EDTA (0.0733%)

(33) 25 grams of iron EDTA (0.0916%)

(34) 3 grams of copper EDTA (0.0110%)

(35) 0.3 grams of Sodium molybdate (Dihydrate) (0.0011%)

(36) 0.03 grams of cobalt EDTA (0.0001%)

(37) 10 grams of boric acid (0.0366%)

(38) 300 grams of potassium nitrate (1.10%)

(39) 400 grams of monopotassium phosphate (1.47%)

(40) 750 grams of magnesium sulfate (2.75%)

(41) 150 grams of potassium sulfate (0.55%)

(42) The following examples show the preparation of concentrated solutions that may contain the necessary components for a plant. The formulations are not intended to specify the required quantities or to restrict the ingredients used. Their main intention is to show the preparation of a concentrated aqueous suspension of this invention.

EXAMPLES

Example 1

(43) Preparation of Concentrated Aqueous Suspension

Example to Prepare 10 Liters of Stock A

(44) The following elements were mixed into 9.3 liters of water at 77° F. and neutral pH (the reason that 9.3 liters of water are added is to get 10 liters of stock A, as salts provide approximately 700 cc of the volume):

(45) 1,000 grams of calcium nitrate

(46) 12 grams of magnesium EDTA

(47) 20 grams of manganese EDTA

(48) 20 grams of zinc EDTA

(49) 25 grams of iron EDTA

(50) 3 grams of copper EDTA

(51) 0.3 grams of sodium molybdate (Dihydrate)

(52) 0.03 grams of cobalt EDTA

(53) 10 grams of boric acid

(54) The weight of the resulting 10 liters of stock A is 10,390 grams.

Example to Prepare 10 Liters of Stock B

(55) The following elements were mixed into 9.3 liters of water at 77° F. and neutral pH (the reason that 9.3 liters of water are added is to get 10 liters of stock B since salts provide approximately 700 cc of the volume):

(56) 300 grams of potassium nitrate

(57) 400 grams of monopotassium phosphate

(58) 750 grams of magnesium sulfate

(59) 150 grams of potassium sulfate

(60) The weight of the resulting 10 liters of stock B is 10,900 grams.

Example to Obtain 27.3 Kilos of Concentrated Aqueous Suspension of Stock A and B in Microfibrillated Cellulose

(61) The reason that 27.3 kilos are prepared is because the proportions, in this formulation, are 6 parts of microfibrillated cellulose (MFC) for every 10 parts of Stock A (10,390 grams) and 10 parts of Stock B (10,900 grams), which results in the aforementioned quantity.

(62) Six kilos of microfibrillated cellulose (MFC) were mixed into 10 liters of stock A and stirred manually for 5 minutes. Then, 10 liters of stock B were added to the resulting solution and stirred manually for 5 minutes. The resulting solution has the initial composition of stock A and stock B as well as the microfibrillated cellulose (MFC), with a pH of 3.4. This means:

(63) 18.6 liters of water (68.2%)

(64) 6,000 grams of microfibrillated cellulose (22.0%)

(65) 1,000 grams of calcium nitrate (3.7%)

(66) 12 grams of magnesium EDTA (0.0440%)

(67) 20 grams of manganese EDTA (0.0733%)

(68) 20 grams of zinc EDTA (0.0733%)

(69) 25 grams of iron EDTA (0.0916%)

(70) 3 grams of copper EDTA (0.0110%)

(71) 0.3 grams of Sodium molybdate (Dihydrate) (0.0011%)

(72) 0.03 grams of cobalt EDTA (0.0001%)

(73) 10 grams of boric acid (0.0366%)

(74) 300 grams of potassium nitrate (1.10%)

(75) 400 grams of monopotassium phosphate (1.47%)

(76) 750 grams of magnesium sulfate (2.75%)

(77) 150 grams of potassium sulfate (0.55%)

(78) The weight of the suspension is 27,290 grams.

Examples of Mixes with and without Precipitates

Example 2

(79) Stock A and Stock B were Mixed

(80) One hundred (100) cc of the obtained stock A and 100 cc of the obtained stock B were mixed at 77° F.; the mixture was stirred and after 3 minutes the emergence of a precipitate was observed.

(81) Thirty minutes later the mixture was stirred again and 2 minutes after that the precipitate was still present, thus confirming that the precipitate does not re-dissolve.

Example 3

(82) Stock A and MFC were Mixed, then Stock B was Added

(83) One hundred (100) cc of the obtained stock A were mixed into 60 grams of microfibrillated cellulose (MFC); the mixture was stirred manually, and then 100 cc of the obtained stock B were immediately added. After 3 minutes, no precipitate emergence was observed. The sample was monitored 24 hours later, 48 hours later and even 90 days later but no modifications were found in its appearance.

Example 4

(84) Stock B and MFC were Mixed, and then Stock A was Added.

(85) In this example, the order of the stocks in the preparation of the aqueous suspension was exchanged. One hundred (100) cc of the obtained stock B were mixed into 60 grams of microfibrillated cellulose (MFC); the mixture was manually stirred and then 100 cc of the obtained stock A were added. After 3 minutes no precipitate was seen emerging. The sample was monitored 24 hours later, 48 hours later and even 90 days later but no modifications were found in its appearance.

Example 5

(86) This example aims to demonstrate that there is no evidence of toxicity in the use of microfibrillated cellulose (MFC) when it is used in a nutrient solution. We prepared 3 identical small hydroponic floating systems where 2 lettuce specimens were grown.

(87) The hydroponic floating system consisted of 20-liter trays where 2 seedlings of lettuce were laid in each one. The trays had a flat bar of polystyrene to support the seedlings and each of them had two holes that enabled the roots to reach the water contained in the trays.

(88) Hydroponic system number 1 was fed with stock A and stock B nutrient solutions, and no microfibrillated cellulose (MFC) was added. Hydroponic system number 2 was fed with a concentrated aqueous suspension of stock A and B in microfibrillated cellulose (MFC) having a microfibrillated cellulose (MFC) concentration of 23%. Hydroponic system number 3 was fed with a concentrated aqueous suspension of stock A and B in microfibrillated cellulose (MFC), having a microfibrillated cellulose (MFC) concentration of 80%.

(89) The amount of solution and/or aqueous suspension added in the three systems had the same electrical conductivity in each case, ensuring the same provision of salts in each of them (electrical conductivity is a measure of the amount of dissolved solids per unit of volume)

(90) The targeted electrical conductivity varied from week to week, depending on the requirements of the lettuce plants in their lifecycle, having 350 ppm in week 1, 700 ppm in week 2, 1,050 ppm in week 3 and 1,400 ppm in week 4.

(91) After week 4 all the lettuce plants had showed equal growth and reached a weight ranging between 270 and 280 grams each.

(92) Thus, we can conclude that microfibrillated cellulose (MFC) allows for the availability of salts for plants as well as the right absorption of nutrients since the growth of specimens studied did not reveal significant variations.

Example 6

(93) Next example shows how microfibrillated cellulose (MFC) prevents calcium sulfate from precipitating even when solutions of calcium nitrate and sulfates in their highest possible concentration at 77° F. and neutral pH are mixed.

(94) Two samples were tested:

(95) A control sample where 3 salt dilutions at its highest possible concentration at 77° F. and neutral pH were mixed, in this order: 180 cc of water *, 100 cc of calcium nitrate solution (1,200 grams in 1 liter of water), 100 cc of potassium sulfate solution (120 grams in 1 liter of water) and 100 cc of manganese sulfate solution (710 grams in 1 liter of water). *One hundred and eighty (180) cc of water was added so as to equate the volumes in the samples (water in the first one and microfibrillated cellulose in the second one).

(96) After mixing them mechanically, we observed a precipitate of 192 grams of calcium sulfate.

(97) In the other sample, 3 salt dilutions at its highest possible concentration at 77° F. and neutral pH, were mixed in microfibrillated cellulose (MFC), following this order: 100 cc of calcium nitrate solution (1,200 grams in 1 liter of water) in 60 grams of MFC, 100 cc of potassium sulfate solution (120 grams in 1 liter) in 60 grams of MFC, and finally 100 cc of manganese sulfate solution (710 grams in a liter) in 60 grams of MFC. The 3 suspensions were mixed altogether.

(98) There were no signs of a precipitate after 48 hours.

Example 7

(99) This example shows that MFC makes it possible to elaborate suspensions of homogeneously distributed salts that contain solids in a much higher proportion than the quantity of salts that could be contained in a water solution of the same volume.

(100) We ran two sample tests.

(101) A control sample where potassium sulfate was added in an amount that exceeded twice its solubility in water at 77° F. and neutral pH (111 g/L). More specifically, we mixed 28.8 grams of potassium sulfate in 130 cc of water at 77° F. It was stirred manually and immediately after that a precipitate of potassium sulfate was noted.

(102) Sample number 2 consisted of the same amount of potassium sulfate contained in the control sample (that is, 28.8 grams) that was added into a suspension of the same volume (130 cc) with microfibrillated cellulose (MFC) at 23% (30 grams of microfibrillated cellulose in 100 cc of water). It was stirred manually and after 5 minutes no decantation of potassium sulfate was observed. The sample was monitored 24 hours later, 48 hours later and even 90 days after without having observable modifications in its appearance.

(103) The suspension object of the present invention has the following advantages over the prior art:

(104) Aqueous suspension permits to have in only one solution the combination of salts whose concentration would naturally lead to precipitate.

(105) It permits to elaborate complete formulations that are totally balanced for each type of crop in only one suspension.

(106) Simplification over the use of fertilizers, since there is no longer need to handle several solutions such as stock A and stock B.

(107) Lower transportation costs and carbon footprint reduction due to the possibility to transport a greater amount of salts in the same volume.

(108) Reduction in packaging as a result of the fewer wrappings needed to deliver the complete formulations.

(109) Product shelf-life: the product shelf-life increases due to the stability of the suspension

(110) Lower storage costs and convenient stock management.