Title of Invention

"A PROCESS FOR PREPARING AN ADSORBENT FOR WATER ARSENIC TREATMENT"

Abstract A process for preparing an adsorbent for water arsenic treatment comprising the steps of mixing 1 to 2 parts by weight of calcium chloride with 100 parts by weight of cement and adding 20 to 30 parts by weight of water, based on the weight of cement thereto to make a paste, pouring said paste Mo a mould and allowing the same to set lo obtain a set paste, curing said paste to obtain a cured paste, subjecting the cured paste to granulation to obtain the granules, treating the same with a copper sulphate solution followed by washing and drying to obtain the adsorbent.
Full Text 1A -
[FIELD OF THE INVENTION
This invention relates to an absorbent for water arsenic treatment and a method for the preparation thereof.
BACKGROUND OF THE INVENTION
Presence of inorganic arsenic in ground water is a matter of major concern in many countries, and with the consequence that such arsenic contaminated water is consumed as potable water, due to consuming arsenic contaminated water, people are suffering from arsenicosis diseases, such as melanosis, leucomelanosis, keratosis on palm and sole, gangrene, lung, ladder and skin cancer.
Most of the literature available in the art describes laboratory scale or pilot plant procedures. Only one full scale treatment plant with a capacity of 34000 gallons per day was built in taiwan to remove about 1 mg/1 of naturally occurring arsenic from well water to render it potable. In the Taiwan plant, ferric oxide hydrate precipitation was preceded by chlorination, indicating either- that the arsenic was in an arsenite form or that arsenic substance required oxidation.
A plant known in India comprises a mechanically operated arsenic removal plant attached to a pipe network scheme. Ferric salt is used as coagulant. Another plant employs alum precipitation preceded by chlorination followed by sand filtraton. Waste sludges are simply stored in a lined pond.
OBJECTS OF THE INVENTION
It is therefore an object of this invention to propose a new
adsorbent for removal of arsenic from ground water.
It is a further object of this invention to propose an absorbent which will maintain water quality at a level of less than 0.01 to 0.05 mg/1 arsenic content.
It is a still further object of this invention to propose an

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absorbent for water arsenic treatment which is cost-effective by being operationally simple, and requiring no addition of chemical, pH adjustment and external power.
Yet another object of this invention is to propose an absorbent for water arsenic treatment which can be regenerated and reused.
Yet a further object of this invention is to porpose an absorbent for water arsenic treatment which gives out no toxic chemicals.
Further objects and advantages of the invention will be more apparent from the ensuing description.
DESCRIPTION OF THE INVENTION
According to this invention is provided an adsorbent for water arsenic treatment comprising silicates of calcium.
According to this invention there is further provided a process for preparing an adsorbent for water arsenic treatment comprising the steps of mixing calcium chloride with cement and adding water thereto to make a paste, pouring said paste into a mould and allowing the same to set to obtain a set paste, curing said set paste to obtain a cured paste, subjecting the cured paste to granulation to obtain the granules, treating the same with a copper sulphate solution followed by washing and drying to obtain the adsorbent
In accordance with this invention calcium chloride (used in solution form) is mixed with silicates of calcium (XcaO. SiO2) to make a paste by mixing 20-30% tap water. The paste is poured into a mould and is kept for 24-48 hours for setting. Thereafter, the sample is separated from the mound and is cured with water for 1-7 days or by steam for one hour. The cured material is granulated and sieved with the help of sieves with sieve numbers of 75,150, 210 and 300 urn, to qbtain sizes of 0.107, 0.177 and 0.251 mm. This is followed

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by washing with distilled water and drying. Finally, the material is treated with 0.5 to 1 N Copper Sulphate solution under stirring for 0.5 to 4 hours, preferably about 2 hours, washed with distilled water and dried.
The silicates of calcium used for preparing the adsorbent are dicalcium silicate and tricalcium silicate which are obtained from the cement
Topically, 1 to 2 parts by weight of calcium chloride is mixed with 100 parts by weight of cement, preferably white cement Water is used in a proportion of 20-30 parts by weight, based on the white cement
In ground water, arsenate As(V) species are predominantly occur mainly as HAsO-24 species. This species has two donor electron. When arsenic contaminated ground water passes through the adsorbent material, it is attached on the surface of the adsorbent The mechanism of adsorption is specific adsorption, whereby arsenic is independently adsorbed on the impregnated copper surface as there is a specific affinity, of arsenic towards copper oxide, which is perhaps me functional group responsible for me adsorption.
The invention will now be explained in greater detail with the help of the following example.
EXAMPLE:
Materials used:
(i) J.K. Bond White Cement 1 kg
(ii) Calcium Chloride 10 grams dissolved in 250 ml of tap water (iii) Capper Sulphate 62.5 grams dissolved in 1000 ml of distilled water. Procedure:
(i) Paste is made by mixing Calcium chloride solution to white cement (ii) The prepared paste is poured in a mould and is kept for 24 hours, (iii) The sample is separated from the mould and is cured with steam for 1 hour and is fuially left 3-4 hours for cooling to room temperature.

-4-(iy) The prepared material is granulated and is then sieved with help of a set of Indian
Standard Sieves with sieve numbers of 75,150, 230 and 300 um to obtain sizes of
0.107.0,177 and 0.251 mm. (v) Each fraction of sieved material is washed separately with distilled water to
remove any fine material and allowed to dry in the sun. (vi) Each sun-dried fraction is taken a 1000 ml beaker and Copper sulphate solution
(prepared as mentioned above) is poured till all the material is completely
immersed. The contents of the beaker are stirred in a mechanical stirrer for 2
hours, (vii) The material is now removed from the beaker and ia washed four times with
distilled water, (viii) Finally the material is sun dried and is stored in a bottle.
This adsorbent material is ready for use. This material was then tested for its effectiveness in the removal of Arsenic from water and the results of a mini-column study are provided herein below;


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WE CLAIM:
1. A process for preparing an adsorbent for water arsenic treatment
comprising the steps of mixing 1 to 2 parts by weight of calcium chloride
with 100 parts by weight of cement and adding 20 to 30 parts by weight of
water, based on the weight of cement thereto to make a paste, pouring
said paste into a mould and allowing the same to set to obtain a set paste,
curing said paste to obtain a cured paste, subjecting the cured paste to
granulation to obtain the granules, treating the same with a copper
sulphate solution followed by washing and drying to obtain the adsorbent.
2. The process as claimed in claim 1, wherein said cement used is white
cement.
3. The process as claimed in claim 1, said cement used is white cement.
4. The process as claimed In claim 1, wherein said paste Is alowed to set for
24 to 48 hours.
5. The process as claimed In claim 1, wherein said sample of set paste is
separated from the mould before being subjected to the step of curing with
water or steam.
6. The process as claimed In claim 5, wherein the sample is cured with water
for 1 to 7 days or with steam for ore.
1. The process as claimed In claim 2, wherein said cured sample Is
granulated and separated through sieves into different sizes for eg. 0.107, 0.177 and 0.261 mm.

8. The process act claimed in claim 2, wherein the granulated simple Is
treated with a 0.9 to 1 N Copper Sulphate solution.
9. The process as claimed in claim 8, wherein the granulated sample is
treated with the copper sulphate solution for a period of 0.6 to 4 hours.
10. An adsorbent for water arsenic removal comprising silicates of calcium.
11. An adsorbent for water arsenic removal substantial as herein described.
12. A process for water arsenic removal substantially as herein described.
A process for preparing an adsorbent for water arsenic treatment comprising the steps of mixing 1 to 2 parts by weight of calcium chloride with 100 parts by weight of cement and adding 20 to 30 parts by weight of water, based on the weight of cement thereto to make a paste, pouring said paste Mo a mould and allowing the same to set lo obtain a set paste, curing said paste to obtain a cured paste, subjecting the cured paste to granulation to obtain the granules, treating the same with a copper sulphate solution followed by washing and drying to obtain the adsorbent.


Documents:

01151-cal-1998-abstract.pdf

01151-cal-1998-claims.pdf

01151-cal-1998-correspondence.pdf

01151-cal-1998-description(complete).pdf

01151-cal-1998-description(provisonal).pdf

01151-cal-1998-form-1.pdf

01151-cal-1998-form-2.pdf

01151-cal-1998-form-5.pdf

01151-cal-1998-letters patent.pdf

01151-cal-1998-p.a.pdf


Patent Number 206831
Indian Patent Application Number 1151/CAL/1998
PG Journal Number 20/2007
Publication Date 18-May-2007
Grant Date 15-May-2007
Date of Filing 30-Jun-1998
Name of Patentee JAGADISH CHANDRA SAHA(RESEARCH SCHOLAR)
Applicant Address INDIAN INSTITUTE OF TECHNOLOGY, KHARAGPUR 721302,
Inventors:
# Inventor's Name Inventor's Address
1 JAGADISH CHANDRA SAHA RESEARCH SCHOLAR OF INDIAN INSTITUTE OF TECHNOLOGY,KHARAGPUR 721 302, INDIA
PCT International Classification Number B01D 11/04
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA