Household water filter element for removing radioactive substances

Patent metadata

Field	Value
Publication number	US-9731227-B2
Application number	US-201414501058-A
Country	US
Kind code	B2
Filing date	Sep 30, 2014
Priority date	Oct 10, 2013
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

The present invention relates to a filter element for disinfecting, cleaning and purifying household water, by removing pollutants such as heavy metals, bacteria, VOCs, and even radioactive substance. The present filter element comprises activated carbon, ion exchange resins (cationic and anionic), biopolymer and transitional metal oxide. Said biopolymer and transitional metal oxide are both in particle form and said transitional metal oxide particle can be either incorporated into the biopolymer particle or directly incorporated into the present filter element as individual particle. Maximum capacity of the present filter element can reach up to 150 L of household water. Some of the pollutants can be removed by up to 99% by the present filter element. A method of preparing the present filter element is also disclosed herein.

First claim

What is claimed is:

1. A filter element for disinfecting, cleaning and purifying household water comprising activated carbon, ion exchange resins, biopolymer, and metal oxide; said ion exchange resins including cationic and anionic ion exchange resins; said biopolymer being in particle form ranging from 1 μm to 100 μm; said metal oxide also being in particle form ranging from 10nm to 10 μm and incorporated into said biopolymer particle through in-situ process to form a biopolymer-metal oxide particle; said activated carbon, cationic ion exchange resins, anionic ion exchange resins, and the biopolymer-metal oxide particle having a weight ratio of 25:41:17:17 in said filter element and at said weight ratio the filter element having a maximum capacity of about 150 L household water to be filtered,
wherein said metal oxide is hydroxy iron oxide (α-FeOOH) and said biopolymer-metal oxide particle is chitosan/hydroxy iron oxides/alginate (CHA) particle.

2. The filter element of claim 1 , wherein pollutants to be removed from the water by said filter element comprise heavy metals, volatile organic compounds (VOCs), halogen, bacteria and radioactive substances.

3. The filter element of claim 2 , wherein said heavy metals comprise cadmium, lead, silver, zinc, and copper.

4. The filter element of claim 2 , wherein said VOCs comprise benzene, toluene, and ethylbenzene.

5. The filter element of claim 2 , wherein said halogen comprises chlorine.

6. The filter element of claim 2 , wherein said bacteria comprises E. coli.

7. The filter element of claim 2 , wherein said radioactive substances comprise radioactive barium, strontium, and iodine.

8. A household water filtering system comprising the filter element of claim 1 .

9. A method of preparing the filter element of claim 1 , said method comprising:
(a) preparing hydroxy iron oxide (α-FeOOH) nanoparticles;
(b) incorporating said α-FeOOH nanoparticles obtained from (a) into a first mixture of chitosan and alginate and then stirring thereof until a plurality of chitosan/hydroxy iron oxide/alginate (CHA) particles is formed;
(c) mixing said CHA particles obtained from (b) with activated carbon, ion exchange resins to form a second mixture;
(d) adding said second mixture obtained from (c) into a filter housing to form the filter element;
(e) washing said filter element with deionized water until filtrate becomes clear.

10. The method of claim 9 , wherein said preparing in (a) comprises dissolving iron (II) sulphate (FeSO 4 .H 2 O) into a mixture of H 2 O and glycerol in a volume ratio of 7:1 and stirring the mixture for at least 10 minutes, followed by transferring the mixture into an autoclave to heat up at about 120° C. for 24 hours, collecting precipitate formed after heating overnight, washing said precipitate with another mixture of H 2 O and glycerol, and drying the washed precipitate at 60° C. for about an hour; hydroxy iron oxide nanoparticles are formed after said drying.

11. The method of claim 9 , wherein said incorporating in (b) comprises mixing said hydroxy iron oxide nanopartieles in the first mixture of chitosan at 2 wt. % and sodium alginate at 0.5 wt. %, followed by adding said mixture drop by drop into 0.5 wt. % of calcium chloride under stirring until the CHA particles are formed.

Assignees

• Nano & Advanced Materials Inst Ltd

Inventors

• Li Jifan
• Ho Yee Man
• Lee Ka Chun
• Chan Wai Yan

Classifications

• C02F2101/322

  Volatile compounds, e.g. benzene · CPC title

• C02F1/286

  using natural organic sorbents or derivatives thereof · CPC title

• C02F2001/425

  using cation exchangers · CPC title

• B01D24/001 Primary

  Making filter elements not provided for elsewhere · CPC title

• C02F2001/427

  using mixed beds · CPC title