Chloramine and chlorine removal material and methods for making the same
AssigneeCalgon Carbon Corporation
InventorsJason Mazzoccoli, Walter G. Tramposch, Ryan Walker, Robert H. Vaughn
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Abstract
Sorbent materials are described that have enhanced performance in removing chlorine and chloramine, among other toxic compounds. The sorbent materials are formed by a process which includes steps of oxidation, adding a nitrogen-containing compound, and calcining the sorbent. The processes of forming the sorbent materials are also disclosed. The sorbent materials have excellent performance as measured by a chloramine and/or chlorine destruction number, and the sorbents retain a high nitrogen edge concentration. The sorbent materials may also be incorporated into devices such as filter assemblies.
Claims32
A method for making a sorbent, comprising:
- providing a first sorbent feedstock which has not been exposed to a nitrogen containing precursor and selected from the group consisting of activated carbon, reactivated carbon, and a combination thereof,
- oxidizing the first sorbent feedstock at a temperature of about 400° C. to about 900° C. to form an oxidized sorbent feedstock,
- adding a nitrogen containing precursor to the oxidized sorbent feedstock in an amount of about 1 mole of nitrogen per 10 moles of carbon, wherein the nitrogen containing precursor is a reduced nitrogen compound, and
- heating the oxidized sorbent feedstock to a temperature of at least about 400° C. under an inert atmosphere to form a calcined sorbent feedstock,
- wherein the first sorbent feedstock, oxidized sorbent feedstock, and calcined sorbent feedstock are not subsequently activated with one or more of H2O, CO2, or O2,
- wherein the sorbent has a chloramine destruction number (CDN) of at least about 4.0,
- wherein the CDN is the absolute value of the first order linear kinetic fit, multiplied by 1000, that is applied to natural log of a concentration of chloramine in water versus time, and
- wherein the initial concentration of chloramine is decreased over a period of 150 minutes.
A sorbent formed by a method comprising the steps of:
- providing a first sorbent feedstock which has not been exposed to a nitrogen containing precursor and selected from the group consisting of activated carbon, reactivated carbon, and a combination thereof,
- oxidizing the first sorbent feedstock at a temperature of about 400° C. to about 900° C. to form an oxidized sorbent feedstock,
- adding a nitrogen containing precursor to the oxidized sorbent feedstock in an amount of about 1 mole of nitrogen per 10 moles of carbon, wherein the nitrogen containing precursor is a reduced nitrogen compound, and
- heating the sorbent feedstock to a temperature of at least about 400° C. under an inert atmosphere to form a calcined sorbent feedstock,
- wherein the first sorbent feedstock, oxidized sorbent feedstock, and calcined sorbent feedstock are not subsequently activated with one or more of H2O, CO2, or O2,
- wherein the sorbent has a chloramine destruction number (CDN) of at least about 4.0,
- wherein the CDN is the absolute value of the first order linear kinetic fit, multiplied by 1000, that is applied to natural log of a concentration of chloramine in water versus time, and
- wherein the initial concentration of chloramine is decreased over a period of 150 minutes.
Dependencies are inferred from the claim text.