Guanidine-functionalized metal silicate particles and methods of making and using such particles

1. A plurality of guanidine-functionalized metal silicate particles, comprising:

a metal silicate particle that are modified with at least one silane having the formula

X 3-n R a n Si—Y-G,

wherein:

n is 0, 1, or 2;

each R a , if present, is independently an alkyl, aralkyl, or aryl;

Y is a divalent group comprising an alkylene having 2 to 20 carbons;

G is a guanidine group of the formula —NH—C(═NH)—NH 2 ; and

each X is independently alkoxy or acyloxy, wherein the at least one silane is covalently bonded to each metal silicate particle through at least one oxygen atom,

wherein the plurality of guanidine-functionalized metal silicate particles is in a particulate form,

wherein the guanidine-functionalized metal silicate particles are made by:

a) reacting an O-methylisourea salt with a linker comprising the formula

X 3-n R a n Si—Y—NH 2 ,

wherein:

n, R a , Y, and X are each as defined above;

to form a guanidine-functionalized linker; and

b) forming a mixture of the guanidine-functionalized linker and metal silicate particles, such that the guanidine-functionalized linker reacts with hydroxyl groups of the metal silicate particles to form covalent bonds between the guanidine-functionalized linker and the metal silicate particles, thereby forming the guanidine-functionalized metal silicate particles.

2. The particles of claim 1 , wherein the divalent group further comprises an arylene, oxy, —NH—, or a combination thereof.

3. The particles of claim 1 , wherein the divalent group is alkylene having 3 to 6 carbons.

4. The particles of claim 1 , wherein the metal silicate particles are magnesium silicate particles.

5. The particles of claim 1 , wherein the metal silicate particles are aluminum silicate particles.

6. The particles of claim 1 , wherein the guanidine-functionalized metal silicate particles have a surface nitrogen content in a range from 1 to 20 atomic percent as measured by X-ray photoelectron spectroscopy (XPS).

7. The particles of claim 1 , wherein n is 0 or 1, and wherein a silane forms a covalent bond with a second silane having the formula X 3-n R a n Si—Y-G, wherein: n, R a , Y, and X are each as defined in claim 1 .

8. The particles of claim 1 , wherein the particulate form of the plurality of guanidine-functionalized metal silicate particles is a powder.

9. The particles of claim 1 , wherein step (b) further comprises adding water to the mixture in an amount ranging from 0.1 to 5 equivalents relative to the amount of the guanidine-functionalized linker.

10. A method of making the guanidine-functionalized metal silicate particles of claim 1 , the method comprising:

a) reacting an O-methylisourea salt with a linker comprising the formula

X 3-n R a n Si—Y—NH 2 ,

wherein:

n is 0, 1, or 2;

each R a , if present, is independently an alkyl, aralkyl, or aryl;

Y is a divalent group comprising an alkylene having 2 to 20 carbons; and

each X is independently alkoxy or acyloxy;

to form a guanidine-functionalized linker; and

b) forming a mixture of the guanidine-functionalized linker and metal silicate particles, such that the guanidine-functionalized linker reacts with hydroxyl groups of the metal silicate particles to form covalent bonds between the guanidine-functionalized linker and the metal silicate particles, thereby forming the guanidine-functionalized metal silicate particles.

11. The method of claim 10 , wherein step (b) further comprises adding water to the mixture in an amount ranging from 0.1 to 5 equivalents relative to the amount of the guanidine-functionalized linker.

12. The method of claim 10 , wherein the linker is 3-aminopropyltrimethoxy silane.

13. The method of claim 10 , wherein the metal silicate particles are magnesium silicate particles or aluminum silicate particles.

14. The method of claim 10 , wherein the guanidine-functionalized metal silicate particles have a surface nitrogen content in a range from 1 to 20 atomic percent as measured by XPS.

15. The method of claim 10 , wherein n is 0 or 1, and wherein the guanidine-functionalized linker forms a covalent bond with a second guanidine-functionalized linker according to step (a) of claim 10 .

16. A nonwoven article comprising:

a) a porous fibrous nonwoven matrix; and

b) a plurality of guanidine-functionalized metal silicate particles according to claim 1 enmeshed within the porous fibrous nonwoven matrix.

17. The article of claim 16 , wherein the metal silicate particles are magnesium silicate particles or aluminum silicate particles.

18. A method of removing microorganisms from an aqueous sample, the method comprising:

a) providing a nonwoven article according to claim 16 ;

b) providing a fluid sample containing at least one microorganism strain; and

c) contacting the fluid sample with the nonwoven article such that at least a portion of the at least one microorganism strain is removed from the fluid sample.

19. The method of claim 18 , further comprising detecting the presence of at least one bound microorganism strain.

20. The method of claim 18 , wherein the contacting comprises passing the fluid sample at least once through the nonwoven article.

21. A method of making a nonwoven article according to claim 16 , the method comprising:

a) providing a plurality of fibers;

b) providing a plurality of guanidine-functionalized metal silicate particles according to claim 1 ;

c) mixing the plurality of guanidine-functionalized metal silicate particles and the plurality of fibers together to form a porous fibrous nonwoven matrix having the guanidine-functionalized metal silicate particles enmeshed within the porous fibrous nonwoven matrix; and

d) mixing at least one polymeric binder together with the plurality of guanidine-functionalized metal silicate particles and the plurality of fibers.

22. A filtration device comprising:

a) a container having inlet and outlet ports for liquid passage; and

b) a nonwoven article according to claim 16 contained within the container.