TREATMENT ADDITIVES, METHODS FOR MAKING AND METHODS FOR
CLARIFYING AQUEOUS MEDIA
FIELD OF THE INVENTION
[0001] This invention relates to methods and treatment additives for treating aqueous
media and more particularly, to methods and treatment additives for clarifying aqueous
media.
BACKGROUND OF THE INVENTION
[0002] Wastewater, such as from food and beverage processing, transportation
processing or steel mill processing, often contains suspended matter, which must be
removed to provide suitable water for use in domestic and industrial applications. Raw
influent water, such as from lakes, streams and rivers can also contain suspended
material. The suspended matter may contain large solids that are easily removed by
settling, and other suspended materials that are not easily removed by settling, such as
dispersed colloids or colloidal oils. Suspended materials are typically removed by
clarification, which includes the steps of coagulation, flocculation and sedimentation.
[0003] Additives containing chitosan have been used to enhance clarification, but the
effectiveness was limited, as chitosan has low water solubility and low cationic charge.
Larger amounts of chitosan in the additive cause the additives to become insoluble in the
aqueous media.
[0004] It is desirable to improve clarification methods for removing suspended material
by providing improved and environmental!y-friendly additives and methods.
I
BRIEF DESCRIPTION OF THE INVENTION
[0005 ] In one embodiment, a coagulant includes poly-(METAS)-Chitosan polymer
having repeating units of:
wherein A has the formula of:
and n is an integer from 50 to 5000.
[0006] In another embodiment, a coagulant composition includes chitosan,
methacryloyloxyethyltrimethyl ammonium methyl sulfate and redox initiators.
[0007] In another embodiment, a method for making a coagulant includes polymerizing
2-methacryloyloxyethyltrimethyl ammonium methyl sulfate and chitosan in the presence
of redox initiators.
[0008] In another embodiment, a method for clarifying aqueous media includes adding a
coagulant to the aqueous media, wherein said coagulant includes poly(METAS)-
Chitosan.
[0009] The various embodiments provide a chloride-free and environmentally-friendly
coagulant and process for clarifying oily aqueous media and synthesis of a
poly(METAS)-chitosan coagulant.
BRIEF DESCRIPTION OF DRAWINGS
[0010] Figure 1 is an NMR for the poly(METAS)-Chitosan polymer prepared in
Example 1.
DETAILED DESCRIPTION OF THE INVENTION
[001 1] The singular forms "a," "an" and "the" include plural referents unless the context
clearly dictates otherwise. The endpoints of all ranges reciting the same characteristic are
independently combinable and inclusive of the recited endpoint. All references are
incorporated herein by reference.
[0012] The modifier "about" used in connection with a quantity is inclusive of the stated
value and has the meaning dictated by the context (e.g., includes the tolerance ranges
associated with measurement of the particular quantity).
[0013 ] "Optional" or "optionally" means that the subsequently described event or
circumstance may or may not occur, or that the subsequently identified material may or
may not be present, and that the description includes instances where the event or
circumstance occurs or where the material is present, and instances where the event or
circumstance does not occur or the material is not present.
[0014] In one embodiment, a coagulant includes a polymer, poly(METAS)-Chitosan. In
another embodiment, poly(METAS)-Chitosan has repeating units of:
wherein A has the formula of:
and wherein n is an integer from 50 to 5000. In another embodiment, n is an integer from
100 to 1000. In another embodiment, n is an integer from 100 to 500.
[0015] In one embodiment, poly(METAS)-Chitosan polymer has a viscosity measured at
25 C in the range of from about 500 cps to about 3000 cps. In another embodiment, the
poly(METAS)-Chitosan polymer has a viscosity in the range of from about 500 cps to
about 2000 cps. In another embodiment, the poly(METAS)-Chitosan polymer has a
viscosity in the range of from about 500 cps to about 1500 cps.
[0016] In one embodiment, the poly(METAS)-Chitosan polymer includes 2-
methacryloyloxyethyltrimethyl ammonium methyl sulfate groups grafted onto a chitosan
backbone. The grafted groups improve the performance of the chitosan polymer by
increasing the percent actives of the product while maintaining the solubility of the
product in water at high mole ratios of chitosan.
[0017] The coagulant aids in clarifying aqueous media. In one embodiment, the aqueous
media may be any type of oily aqueous media or aqueous media containing colloidal or
suspended materials. In one embodiment, the aqueous media may be raw water, storm
water or wastewater. In one embodiment, the wastewater may be from food and
beverage processing, transportation processing or steel mill processing.
[0018] In another embodiment, a coagulant composition includes chitosan,
methacryloyloxyethyltrimethyl ammonium methyl sulfate and redox initiators.
[0019] Chitosan is a linear polysaccharide containing deacetylated units and acetylated
units. In one embodiment, the deacetylated unit may be p-(l-4)-linked D-glucosamine.
In another embodiment, the acetylated unit may be N-acetyl-D-glucosamine units.
Chitosan may be prepared by deacylating chitin with a strong alkali and is available
commercially from India Sea Foods. Chitosan may be present from about 5 percent by
weight to about 30 percent by weight, based on the weight of the composition. In another
embodiment, chitosan may be present from about 10 percent by weight to about 30
percent by weight, based on the weight of the composition. In another embodiment,
chitosan may be present from about 20 percent by weight to about 30 percent by weight,
based on the weight of the composition.
[0020] 2-Methacryloyloxyethyltrimethyl ammonium methyl sulfate is available
commercially, such as from Ciba. 2-Methacryloyloxyethyltrimethyl ammonium methyl
sulfate may be present from about 25 percent by weight to about 75 percent by weight,
based on the weight of the composition. In another embodiment, 2-
Methacryloyloxyethyltrimethyl ammonium methyl sulfate may be present from about 30
percent by weight to about 70 percent by weight, based on the weight of the composition.
In another embodiment, 2-Methacryloyloxyethyltrimethyl ammonium methyl sulfate may
be present from about 35 percent by weight to about 65 percent by weight, based on the
weight of the composition.
[0021] The redox initiators provide the oxidizing and reducing agents that are needed to
form radicals to polymerize the chitosan-based polymer. In one embodiment, the redox
initiator includes an oxidizing agent and a reductant. In another embodiment, the
oxidizing agent may be t-butyl hydroperoxide or potassium persulfate. In another
embodiment, the reductant may be sodium metabisulfite, sodium hydrosulfate or sodium
thiosulfate. The redox initiators may be present from about percent by weight to about
0 percent by weight, based on the weight of the composition. In another embodiment,
the redox initiators may be present from about 3 percent by weight to about 7 percent by
weight, based on the weight of the composition. In one embodiment, the oxidizing agent
may be present from about 0.5 percent by weight to about 5 percent by weight, based on
the weight of the composition. In another embodiment, the oxidizing agent may be
present from about 1 percent by weight to about 5 percent by weight, based on the weight
of the composition. In one embodiment, the reductant may be present from about 0.5
percent by weight to about 5 percent by weight, based on the weight of the composition.
In another embodiment, the reductant may be present from about 1 percent by weight to
about 5 percent by weight, based on the weight of the composition.
[0022] In one embodiment, the composition includes from about 5 percent by weight to
about 30 percent by weight chitosan, from about 25 percent by weight to about 75 percent
by weight of 2-methacryloyloxyethyltrimethyl ammonium methyl sulfate and from about
1 percent by weight to about 10 percent by weight of redox initiators, wherein the
weights are based on the total weight of the composition.
[0023] In another embodiment, an acid may be added. The acid helps to increase
grafting by dissolving the chitosan to prepare a homogenous solution. In one
embodiment, the acid may include citric acid, acetic acid, methanesulfonic acid or
sulfamic acid. In one embodiment, the acid is present from about 10 percent by weight to
about 50 percent by weight, based on the weight of the composition. In another
embodiment, the acid may be present from about 10 percent by weight to about 30
percent by weight, based on the weight of the composition. In another embodiment, the
acid may be present from about 10 percent by weight to about 20 percent by weight,
based on the weight of the composition.
[0024] In another embodiment, a method for making a coagulant includes polymerizing
2-methacryloyloxyethyltrimethyl ammonium methyl sulfate and chitosan in the presence
of redox initiators.
[0025] Chitosan is described above. In one embodiment, chitosan may be present from
about 5 percent by weight to about 30 percent by weight, based on the weight of the
reactants. In another embodiment, chitosan may be present from about 10 percent by
weight to about 30 percent by weight, based on the weight of the reactants. In another
embodiment, chitosan may be present from about 20 percent by weight to about 30
percent by weight, based on the weight of the reactants.
[0026] In one embodiment, chitosan is polymerized with 2-
methacryloyloxyethyltrimethyl ammonium methyl sulfate. The chitosan forms a
backbone to which the 2-methacryloyloxyethyltrimethyl ammonium methyl sulfate is
grafted. In one embodiment, 2-methacryloyloxyethyltrimethyl ammonium methyl sulfate
may be present from about 25 percent by weight to about 75 percent by weight, based on
the weight of the reactants. In another embodiment, 2-methacryloyloxyethyltrimethyl
ammonium methyl sulfate may be present from about 30 percent by weight to about 70
percent by weight, based on the weight of the reactants. In another embodiment, 2-
methacryloyloxyethyltrimethyl ammonium methyl sulfate may be present from about 35
percent by weight to about 65 percent by weight, based on the weight of the reactants.
[0027] In one embodiment, the chitosan and 2-methacryloyloxyethyltrimethyl
ammonium methyl sulfate are polymerized in the presence of redox initiators, which are
described above. The redox initiators may be present from about 1 percent by weight to
about 10 percent by weight, based on the weight of the reactants. In one embodiment, the
redox initiators may be present from about 3 percent by weight to about 7 percent by
weight, based on the weight of the reactants. In one embodiment, the redox initiators
includes an oxidizing agent and a reductant, which are described above. In one
embodiment, the oxidizing agent may be present from about 0.5 percent by weight to
about 5 percent by weight, based on the weight of the reactants. In another embodiment,
the oxidizing agent may be present from about 1 percent by weight to about 5 percent by
weight, based on the weight of the reactants. In another embodiment, the reductant may
be present from about 0.5 percent by weight to about 5 percent by weight, based on the
weight of the reactants. In another embodiment, the reductant may be present from about
1 percent by weight to about 5 percent by weight, based on the weight of the reactants.
[0028] The chitosan and 2-methacryloyloxyethyltrimethyl ammonium methyl sulfate
may be polymerized in any suitable manner. In one embodiment, the polymerization
may be at an elevated temperature. In another embodiment, the polymerization may
occur at a temperature from about 40°C to about 90°C. In another embodiment, the
temperature of the polymerization may be from about 40°C to about 85°C. In another
embodiment, the temperature may be from about 50°C to about 80°C.
[0029] In one embodiment, the coagulant polymer may be prepared in a single reactor.
In one embodiment, the reaction may occur in an aqueous solution. In another
embodiment, the aqueous solution may be water.
[0030] In one embodiment, the resulting polymer is poly(METAS)-Chitosan. In another
embodiment, the polymer has repeating units of:
wherein A has the formula of:
and wherein n is an integer from 50 to 5000. In another embodiment, n is an integer from
100 to 1000. In another embodiment, n is an integer from 100 to 500.
[0031] In one embodiment, poly (METAS)-Chitosan polymer has a viscosity measured at
25°C in the range of from about 500 cps to about 3000 cps. In another embodiment, the
poly(METAS)-Chitosan polymer has a viscosity in the range of from about 500 cps to
about 2000 cps. In another embodiment, the poly (METAS)-Chitosan polymer has a
viscosity in the range of from about 500 cps to about 1500 cps.
[0032] In another embodiment, chitosan and 2-methacryloyloxyethyltrimethyl
ammonium methyl sulfate may be polymerized in the presence of an acid. The acid helps
to increase grafting by dissolving the chitosan to prepare a homogenous solution. In one
embodiment, the acid may include citric acid, acetic acid, methanesulfonic acid or
sulfamic acid. In another embodiment, the acid is present from about 10 percent by
weight to about 50 percent by weight, based on the weight of the reactants. In another
embodiment, the acid is present from about 10 percent by weight to about 30 percent by
weight, based on the weight of the reactants. In another embodiment, the acid is present
from about 10 percent by weight to about 20 percent by weight, based on the weight of
the reactants.
[0033] In another embodiment, a method for clarifying aqueous media includes adding a
coagulant to the aqueous media, wherein said coagulant includes poly(METAS)-
Chitosan.
[0034] In one embodiment, the aqueous media may be any type of oily aqueous media or
aqueous media containing colloidal or suspended materials. In one embodiment, the
aqueous media may be raw water, storm water or wastewater. In one embodiment, the
wastewater may be from food and beverage processing, transportation processing or steel
mill processing. In one embodiment, the wastewater may contain dispersed colloids or
colloidal oils. The wastewater may contain any amount of colloidal material or oily
material and any amount of colloidal material or oily material may be removed by the
coagulant. In one embodiment, the wastewater may contain from about 0.01 percent by
weight to about 4 percent by weight of colloidal material or oily material, based on the
weight of the water.
[0035] The coagulant and poly(METAS)-Chitosan are described above. The coagulant
may be added in any suitable manner. In one embodiment, the coagulant is injected into
the aqueous media. In another embodiment, the coagulant is added via dilution with a
chemical feed pump, such as an LMI pulse pump. In one embodiment, the coagulant is
added in a continuous manner.
[0036] In one embodiment, the coagulant is added to the aqueous media in any amount
suitable for clarifying the aqueous media. In one embodiment, the coagulant may be
added in an mount of from about 0.5 ppm by volume to about 1000 ppm by volume,
based on the volume of the aqueous media. In another embodiment, the coagulant may
be added in an amount of from about 1 ppm by volume to about 1000 ppm by volume,
based on the volume of the aqueous media. In another embodiment, the coagulant may
be added in an amount of from about 100 ppm by volume to about 1000 ppm by volume,
based on the volume of the aqueous media. In another embodiment, the coagulant may
be added in an amount of from about 200 ppm by volume to about 950 ppm by volume,
based on the volume of the aqueous media.
[0037] In order that those skilled in the art will be better able to practice the present
disclosure, the following examples are given by way of illustration and not by way of
limitation.
EXAMPLES
EXAMPLE 1
[0038] A 4-necked flask was equipped with a mechanical stirrer, reflux condenser,
thermometer socket and nitrogen inlet. 250.00 g of deionized water was charged to the
reactor flask. The flask was stirred at 300-350 rpm and a nitrogen blanket was applied.
The reaction mass was heated to 25-30°C. 2 1 g of Chitosan was added to the flask. The
flask was heated to 72-75°C. 12 g of glacial acetic acid was added to the Chitosan. The
mixture was stirred for 60 minutes and then cooled to 35-40°C. 50 g of 2-
Methacryloyloxyethyltrimethylammonium methyl sulfate solution was added to the flask
and nitrogen sparged for 20 minutes. The flask was heated to 73-75°C and a sodium
metabisulfite solution (2.05 g in 8.72 g of water) and t-butyl hydroperoxide (t-BHP) (2.68
g in 8.32 g of water) were charged to the flask solution simultaneously over a period of 1
hour via syringe pump. The temperature was maintained at 73-75°C and held at that
temperature for 1 hour. The mixture was cooled to room temperature. The resulting
polymer yielded a homogeneous viscous light- yellowish solution of poly(METAS)-
Chitosan having 12% wt. solids.
[0039] The viscosity of the resulting polymer was measured using a standard Brookfield
viscometer, DVII, Spindle 6 1 at 25°C and 30 rpm. The resulting polymer had a viscosity
of 700 cps. The presence of an ester group in infrared spectroscopy after purification
confirms the grafting process and an NMR confirms the polymer structure as shown in
Figure .
EXAMPLE 2
[0040] A synthetic oily wastewater was prepared. An oily mixture was prepared by
blending mineral oil, oleic acid and Triton-CFIO, which is a linear alcohol ethoxylate and
commercially available from The Dow Chemical Company. The mixture contained 43%
mineral oil, 37% oleic acid and 20% triton-CFlO. The mixture was stirred on a hot plate
for 15 minutes followed by blending the mixture in a blender for 10 minutes. 15g of the
oily mixture was added to a blender with 385g of distilled water and blended for seven
minutes. The resulting emulsion was diluted to 1:9 by volume using tap water. The pH
of the wastewater was 7.0.
[004 1] An ASTM D2035-80 testing procedure was used to determine the efficacy of the
treatment. Wastewater samples were added to six 300-ml jars and placed in a six-paddle
stirrer. The treatment coagulant as prepared in Example 1 was added to the jars in the
dosages shown in Table 2. The samples were stirred at a speed of 100 rpm for two
minutes and at a speed of 35 rpm for 10 minutes. Then the speed was reduced to 0 rpm
and a testing sample was taken from the bottom of the jar after 30 minutes. The testing
sample was measured using a turbidity meter. The turbidity of the testing sample was
noted and compared to the turbidity of a blank sample with no coagulant treatment,
which had a turbidity of 4186. Data is shown in Table 2.
Table 2
Sample Treatment Turbidity
[0042] The turbidity significantly decreases with the addition of the treatment coagulant.
EXAMPLE 3
[0043] Wastewater from the Effluent Treatment Plant of a Refinery was tested in
accordance with Example 2. The wastewater had a pH of 10.9, a conductivity of 1365, a
Total Dissolved Solids (TDS) of 946.4 and a turbidity of 200. Data is shown in Table 3.
Table 3
[0044] The treatment significantly reduced the turbidity.
EXAMPLE 4
[0045] Wastewater from a storm water collection pond was tested in accordance with
Example 2. The wastewater had a pH of 8 and a turbidity of 93 NTU. The wastewater
was treated with the coagulant prepared in Example 1 and chitosan. Data is shown in
Table 4.
Table 4
[0046] The treatment for samples 1-6 shows decreased turbidity of the wastewater at
lower doses than the chitosan treatment.
[0047] While typical embodiments have been set forth for the purpose of illustration, the
foregoing descriptions should not be deemed to be a limitation on the scope herein.
Accordingly, various modifications, adaptations and alternatives may occur to one skilled
in the art without departing from the spirit and scope herein.

WHAT IS CLAIMED IS:
1. A coagulant comprising poly-METAS-Chitosan polymer having repeating units
wherein A has the formula of:
and wherein n is an integer from 50 to 5000.
2. The coagulant of claim 1, wherein the poly(METAS)-Chitosan polymer has a
viscosity in the range of from about 500 cps to about 3000 cps.
3. A coagulant composition comprising chitosan, methacryloyloxyethyltrimethyl
ammonium methyl sulfate and redox initiators.
4. The coagulant composition according to claim 3 wherein chitosan is present from
about 5 percent by weight to about 30 percent by weight, based on the weight of the
composition.
5. The coagulant composition according to claim 3 wherein 2-
Methacryloyloxyethyltrimethyl ammonium methyl sulfate is present from about 25
percent by weight to about 75 percent by weight, based on the weight of the composition.
6. The coagulant composition according to claim 3 wherein the redox initiator is
present from about 1 percent by weight to about 10 percent by weight, based on the
weight of the composition.
7. The coagulant composition according to claim 3 wherein the redox initiator
comprises an oxidizing agent and a reductant.
8. The coagulant composition according to claim 7 wherein the oxidizing agent is tbutyl
hydroperoxide or potassium persulfate.
9. The coagulant composition according to claim 7 wherein the oxidizing agent is
present from about 0.5 percent by weight to about 5 percent by weight, based on the
weight of the composition and the reductant is present from about 0.5 percent by weight
to about 5 percent by weight, based on the weight of the composition.
10. The coagulant composition according to claim 7 wherein the reductant is selected
from the group consisting of sodium metabisulfite, sodium hydrosulfate and sodium
thiosulfate.
11. The coagulant composition of claim 3 wherein the composition comprises from
about 5 percent by weight to about 30 percent by weight chitosan, from about 25 percent
by weight to about 75 percent by weight of 2-Methacryloyloxyethyltrimethyl ammonium
methyl sulfate and from about 1 percent by weight to about 10 percent by weight of redox
initiators, wherein the weights are based on the total weight of the composition.
12. The coagulant composition of claim 3 further comprising an acid.
13. The coagulant composition of claim 12, wherein the acid is selected from the
group consisting of citric acid, acetic acid, methanesulfonic acid and sulfamic acid.
14. The coagulant composition of claim 12, wherein the acid is present from about 10
percent by weight to about 50 percent by weight based on the weight of the composition.
15. A method for making a coagulant comprising polymerizing 2-
methacryloyloxyethyltrimethyl ammonium methyl sulfate and chitosan in the presence of
redox initiators.
16. The method according to claim 15 wherein chitosan is present from about 5
percent by weight to about 30 percent by weight, based on the weight of the reactants.
17. The method according to claim 15 wherein 2-Methacryloyloxyethyltrimethyl
ammonium methyl sulfate is present from about 25 percent by weight to about 75 percent
by weight, based on the weight of the reactants.
18. The method according to claim 5 wherein the redox initiator is present from
about 1 percent by weight to about 10 percent by weight, based on the weight of the
reactants.
19. The method according to claim 15 wherein the redox initiator comprises an
oxidizing agent and a reductant.
20. The method according to claim 19 wherein the oxidizing agent is t-butyl
hydroperoxide or potassium persulfate.
21. The method according to claim 20 wherein the oxidizing agent is present from
about 0.5 percent by weight to about 5 percent by weight, based on the weight of the
reactants and the reductant is present from about 0.5 percent by weight to about 5 percent
by weight, based on the weight of the reactants.
22. The method according to claim 1 wherein the reductant is selected from the
group consisting of sodium metabisulfite, sodium hydrosulfate and sodium thiosulfate.
23. The method of claim 15, wherein polymerization is in the presence of an acid.
24. The method of claim 23, wherein the acid is selected from the group consisting of
citric acid, acetic acid, methanesulfonic acid and sulfamic acid.
25. The method of claim 23, wherein the acid is present from about 10 percent by
weight to about 50 percent by weight based on the weight of the composition.
26. The method of claim 15, wherein the polymerization is at an elevated
temperature.
27. The method of claim 26, wherein the polymerization is at a temperature from
about 40°C to about 90°C.
28. A method for clarifying aqueous media comprising adding a coagulant to the
aqueous media, wherein said coagulant comprises poly(METAS)-Chitosan.
29. The method of claim 28 wherein the aqueous media is selected from the group
consisting of raw water, storm water and wastewater.
30. The method of claim 28, wherein the coagulant is added to the aqueous media
an mount of from about 0.5 ppm by volume to about 1000 ppm by volume, based on
volume of the aqueous media.