REMOVAL OF BIOLOGICAL CONTAMINANTS FROM AQUEOUS STREAMS WITH CERIUM (IV) OXIDE COMPOSITIONS

1 . A method for removing biological contaminants from an aqueous stream, comprising:

contacting a cerium (IV) oxide composition with a biological contaminant-containing aqueous stream, wherein the biological contaminant is selected from the group consisting of a bacterium, a yeast, an algae, and a virus, wherein the following are true:

(i) the cerium (IV) oxide composition has a zeta potential at about pH 7 of no more than about 16 mV and of more than about 1 mV;

(ii) the cerium (IV) oxide composition has a crystallite size of more than about 1 nm and no more than about 19 nm;

(iii) the cerium (IV) oxide composition has an acidic site concentration of more than about 0.0001 acidic sites/kg and no more than about 0.020 acidic sites/kg; and

(iv) the cerium (IV) oxide composition has an isoelectric point of more than about pH 8.8,

wherein the contacting of the cerium (IV) oxide composition with the biological contaminant-containing aqueous stream removes at least about 5 million PFU of a bacterium per gram CeO 2 per hour, or at least about 0.3 million PFU of a yeast per gram CeO 2 per hour, or at least about 0.1 million PFU of an algae per gram CeO 2 per hour, or at least about 2 million PFU of a virus per gram CeO 2 per hour.

2 . (canceled)

3 . The method of claim 1 , wherein the biological contaminant is one selected from the group of Klebsiella ocytoca, Saccharomyces cerevisiae, Selenastum capriocornutum , and bacteriophage MS2.

4 . The method of claim 1 , wherein one or more of the following are true:

(v) the cerium (IV) oxide composition has a particle size D 10 of more than about 0.5 μm and no more about 4 μm;

(vi) the cerium (IV) oxide composition has a particle size D 50 of more than about 2 μm and no more about 20 μm; and

(vii) the cerium (IV) oxide composition has a particle size D 90 of more than about 12 μm and no more about 50 μm.

5 - 10 . (canceled)

11 . The method of claim 1 , wherein

zeta potential at about pH 7 is from about 7.5 to about 12.5 mV.

12 - 20 . (canceled)

21 . A method for removing biological contaminants from an aqueous stream, comprising:

contacting a cerium (IV) oxide composition with a biological contaminant-containing aqueous stream, wherein the biological contaminant is selected from the group consisting of a bacterium, a yeast, an algae, and a virus, wherein the cerium (IV) oxide composition has:

(a) a zeta potential at about pH 7 of less than about 16 mV and of more than about 1 mV;

(b) an acidic site concentration of more than about 0.0001 acidic sites/kg and less than about 0.020 acidic sites/kg;

(c) an isoelectric point of more than about pH 8.8; and

(d) at least one of:

(i) a particle size D 10 of more than about 0.5 nm and no more than about 4 μm;

(ii) a particle size D 50 of more than about 2 μm and no more than about 20 μm; and

(iii) a particle size D 90 of more than about 12 μm and no more than about 50 μm;

wherein the contacting of the cerium (IV) oxide composition with the biological contaminant-containing aqueous stream removes at least about 5 million PFU of a bacterium per gram CeO 2 per hour, or at least about 0.3 million PFU of a yeast per gram CeO 2 per hour, or at least about 0.1 million PFU of an algae per gram CeO 2 per hour, or at least about 2 million PFU of a virus per gram CeO 2 per hour.

22 . The method of claim 21 , wherein the cerium (IV) oxide composition has a crystallite size of more than about 1 nm and no more than about 19 nm.

23 . The method of claim 21 , wherein the zeta potential at about pH 7 is from about 7.5 to about 12.5 mV.

24 . The method of claim 21 , wherein the biological contaminant is one selected from the group of Klebsiella oxytoca, Saccharomyces cerevisiae, Selenastum capriocornutum , and bacteriophage MS2.