Trivalent doped cerium oxide compositions for biological contaminant removal

A method for removing biological contaminants comprising:

• providing a particulate oxide composition comprising cerium oxide;
• trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof;
• and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof;
• wherein the cerium oxide is present in an amount greater than the trivalent dopant and wherein the average trivalent dopant to Ce ratio at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the trivalent dopant to Ce ratio at about 15 nm from the surface of the particulate composition;
• contacting the composition with a biological contaminant wherein the biological contaminant is selected from the group consisting of bacteria, viruses, protozoa, fungi, and mixtures thereof;
• and
• removing at least about 90% of the biological contaminant through contact with the composition.

A method for treating a fluid comprising:

• (i) providing a particulate oxide composition comprising cerium oxide;
• trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof;
• and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof;
• wherein the cerium oxide is present in an amount greater than the trivalent dopant and wherein the average trivalent dopant to Ce ratio at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the trivalent dopant to Ce ratio at about 15 nm from the surface of the particulate composition;
• (ii) contacting a gaseous or aqueous stream containing biological contaminant with the composition, wherein the biological contaminant is selected from the group consisting of bacteria, viruses, fungi, protozoa, and mixtures thereof;
• and
• (iii) removing biological contaminant from the gaseous or aqueous stream through contact with the composition.