Journal of Environmental Protection, 2010, 1, 179-182
doi:10.4236/jep.2010.12022 Published Online June 2010 (http://www.SciRP.org/journal/jep)
1
Preparation of High Effective Flocculant for High Density
Waste Drilling Mud
Fanghui Wang, Jing Zou, Hong Zhu*, Kefei Han, Jiantao Fan
School of Science, Beijing University of Chemical and Technology, Beijing, China.
Received February 2nd, 2010; revised May 4th, 2010; accepted May 5th, 2010.
ABSTRACT
To satisfy the requirement on the separation of solid and liquid in waste drilling mud, prepare a high effective floccu-
lant for high density waste drilling mud used starch, 2-Trimethylammonium ethyl methacrylate chloride (DMC) and
acrylamide (AM). The result showed that when the ratio of starch, DMC and AM was 2:1:3, the weight of initiator (po-
tassium persulfate) was 0.2% of the AM, reaction temperature was 65℃ and reaction time was 5h, the performance of
product was the best. The water content in filter cake was 27.6% after the waste drilling mud disposed by the optimiza-
tion flocculant. The flocculent effect of optimization flocculant was superior to that of other flocculant in market.
Keywords: High Density, Waste Drilling Mud, Dispose, Cation
1. Introduction
The waste drilling mud and drilling wastewater were the
inevitable industrial waste while Oil and Gas Exploration
Drilling. They has become one of the most severe pollu-
tion sources, whose effect on environment has been
concerned gradually [1-3].There were many methods
[4-7] to dispose the waste drilling mud and drilling
wastewater, such as, Gravity Separation, Impact, Baffle,
or Spray Separation, Parallel-Plate and Thin-Film Sepa-
ration and Vacuum Separation. The Solid-Liquid Separa-
tion has such advantages as large capacity, simple opera-
tion and using a few equipments [8], it was the most im-
portant and Widely Application method. At deep well
drilling, the component of waste drilling mud was more
and more complexity, the density of waste drilling mud
was higher, and the waste drilling mud treatment was
more harder [9]. The flocculant in market has not deal
with the high density waste drilling mud. So a new
starch-based cation copolymer flocculant for high density
waste drilling mud was prepared.
2. Methods
2.1 Agent
Edible corn starch, 2-Trimethylammonium ethyl metha-
crylate chloride (CP), acrylamide (A.R), potassium per-
sulfate (A.R), sodium hydroxide (A.R).
High density waste drilling mud, the density was 1.639
g/mL and the Solid content was 56.72%.
2.2 Synthesis of Starch-Based Cation Coploymer
Flocculant
Add some deionized water, corn starch and sodium hy-
droxide into a three-neck flask with stirrer. Heat the sys-
tem to 70˚C and stir until starch dissolved completely
(about 30 min), then cool the system to room temperature
and removal of oxygen dissolved in the solution by
blowing continuously nitrogen. After add some AM and
DMC into above system, add the potassium persulfate
solution drop by drop. Keep the system react for a certain
time at a given temperature to gain product.
2.3 Flocculent Treatment
Add some gel breaker to some waste drilling mud, then
add some flocculant to above system and stir, centrifugal
separation (3500 r/min) for 10min. Weight the quality of
filter cake (m1) and soild phase (m2) after baking, gain
the water content in filter cake by the formula as follows:
the water content in filter cake = (m1-m2)/m1.
3. Result and Discussion
3.1 Preparing Conditions of Starch-Based Cation
Copolymer Flocculant
3.1.1 Appropriate Weight Ratio of AM and Starch
The amount of starch was 3 g, DMC dosage was 1 mL,
pH = 7, the reaction temperature was 70˚C, reaction time
was 3 h, the amount of acrylamide was respectively 3 g,
6 g, 9 g, 12 g, the amount of potassium persulfate was

Preparation of High Effective Flocculant for High Density Waste Drilling Mud 180
0.2% of the quality of acrylamide. The flocculent effect
is shown in Figure 1.
Figure 1 showed when m(AM)/m(starch) = 3, the wa-
ter content in filter cake was the minimum (32.3%).
When the m(AM)/m(starch) above 3, the lesser quality of
starch made the active sites for graft reaction decrease, so
the molecular weight of copolymer diminished. The Low
Molecular Weight copolymer could not link tightly with
solid matter in waste drilling mud, so the flocculation
effect was not good.
3.1.2 Appropriate Dosage of DMC
The starch quality was 3 g, the quality of acrylamide was
9 g, pH = 7, the reaction temperature was 70˚C, reaction
time was 3 h, the amount of potassium persulfate was 0.2%
of the quality of acrylamide, DMC dosage respectively
was 1 mL, 2 mL, 3 mL, 4 mL. Study the effect of DMC
dosage on the water content in filter cake (Figure 2).
Figure 2 showed when the DMC dosage was 2 ml, the
water content in filter cake was the lowest. Increasing the
dosage of DMC make the cationic degree of copolymer
increase. The clay in waste drilling mud charged negative,
so the higher of the cationic degree of copolymer was,
1.0 1.5 2.0 2.5 3.0 3.5 4.0
31
32
33
34
35
36
37
38
39
40
water content/%
m(AM)/m(starch)
Figure 1. The effect of m(AM)/m(starch) on water content
in filter cake
1.0 1.5 2.0 2.5 3.0 3.5 4.0
30
32
34
36
38
40
42
44
46
48
water content/%
DMC dosage/mL
Figure 2. The effect of DMC dosage on water content in
filter cake
the more the negative charge neutralized, so the solid
matter in waste drilling mud was more easier to separate
from waste drilling mud. But when the DMC dosage was
greater than 2 mL, the water content in filter cake in-
creased. The reason maybe as follows:
1) Impact of Cl-: The initiator was K2S2O8, Cl- can re-
act with S2O8
2- to form Cl2, Cl atom can act as a chain
termination agent, so that the molecular weight of co-
polymer decreased.
2) Steric Hindrance Effect: DMC with Steric Hin-
drance reduce the probability of collision between DMC
monomer and chain free radical.
Above two factor increase the difficult of Polymeriza-
tion between DMC and starch and AM, so the floccula-
tion effect was not good.
3.1.3 Appropriate Dosage of Initiator
The amount of starch was 3 g, DMC amount was 2mL,
the amount of acrylamide was 9 g, pH = 7, the reaction
temperature was 70˚C, reaction time was 3 h. The amount
of potassium persulfate was respectively 0.1%, 0.2%,
0.3%, 0.4%, 0.5% of the quality of acrylamide. The floc-
culent effect is shown in Figure 3.
From Figure 3 we can see that when the potassium
persulfate dosage was 0.3%, the water content in filter
cake was the lowest. Because when the amount of potas-
sium persulfate increased, the concentration of free radi-
cals increase, grafting reaction rate accelerated, graft
product molecular weight was larger. But when the qual-
ity of potassium persulfate was more than 0.3% that of
acrylamide monomer, the water content of filter cake
actually increased. The increasing concentration of po-
tassium persulfate caused homopolymerization reaction
probability of monomer increase and the termination of
free radicals also increase, so the copolymer molecular
weight was not big enough and the water content in filter
also increased.
3.1.4 Reaction Time
The amount of starch was 3 g, DMC amount was 2 mL,
0.1 0.2 0.3 0.4 0.5
30
32
34
36
38
40
42
water content/%
The amount of potassium persulfate/%
Figure 3. The effect of potassium persulfate dosage on wa-
ter content in filter cake

Preparation of High Effective Flocculant for High Density Waste Drilling Mud181
the amount of acrylamide was 9 g, pH = 7, the amount of
potassium persulfate was 0.3% of the quality of acryla-
mide, reaction temperature was 70˚C, the reaction time
was respectively 3 h, 4 h, 5 h, 6 h, 7 h. The flocculent
effect is shown in Figure 4.
As can be seen from Figure 4, the best reaction time
was 4 h, this was because early in the reaction system,
the active center of grafting reaction was more, the reac-
tion rate was quick. But when the reaction time was more
than 4 h, the number of grafting points decreased, which
made grafting reaction rate slow down, so the grafting
yield had fallen and the water content in filter cake cor-
respondingly increased.
3.1.5 Reaction Temperature
The amount of starch was 3 g, DMC amount was 2 mL,
the amount of acrylamide was 9 g, pH = 7, the amount of
potassium persulfate was 0.3% of the quality of acryla-
mide, reaction time was 4 h, the reaction temperature was
respectively 50˚C, 55˚C, 60˚C, 65˚C, 70˚C, 75˚C. The
flocculent effect is shown in Figure 5.
The reaction temperature at 65˚C, the water content in
filter cake was the lowest. Because temperature rising
within a certain range can increases the degree of starch
34567
30
32
34
36
38
40
42
44
46
water content/%
reaction time/h
Figure 4. The effect of reaction time on water content in
filter cake
50 55 60 65 70 75
28
32
36
40
44
48
52
water content/%
reaction temperature/℃
Figure 5. The effect of reaction temperature on water con-
tent in filter cake
swelling in water, thus ensure the reaction in the homo-
geneous and be propitious to disperse initiator and mono-
mer. When the temperature rose exceeds 65˚C, the chain
termination reaction rate increased, which lead to lower
grafting yield, so the water content in filter cake was
higher.
3.2 Analysis of FTIR
Figure 6 and Figure 7 are respectively FTIR spectra of
starch and copolymer flocculant. As can be seen from the
Figure 6, the peak of IR spectra of -OH symmetric
stretching vibration in starch glucose unit appeared at
3440 cm-1 and 3442 cm-1. From Figure 7, we can know
the peak of IR spectra of C=O stretching vibration and
-NH2, -CH2 stretching vibration in copolymer flocculant
appeared respectively at 1670 cm-1, 3198 cm-1, 1027 cm-1.
There be should have two absorption peak at 3198 cm-1,
but it overlapped with the strong broad hydroxyl peak of
starch, so there was only a single peak. The absorption
peak appeared at 1618 cm-1 was the -NH2 bending vibra-
tion characteristic peaks. So, there must have some struc-
tural units of AM and DMC in the starch- based cation
copolymer flocculant.
3.3 Flocculent Effect
From Figure 8 we can see that adding the same amount
of flocculant, the flocculent effect of organic flocculants
was better than that of inorganic coagulant, but the re-
sults are not satisfactory, the water content in filter cake
4000 3000 2000 1000
v/cm-1
2928
1651
1021
3442
Figure 6. FTIR spectra of corn starch
4000 3000 2000 1000
v/cm-1
1670
1618
3198
1027
2928
3410
Figure 7. FTIR spectra of starch-based cation copolymer
flocculant

Preparation of High Effective Flocculant for High Density Waste Drilling Mud 182
123456
0
10
20
30
40
50
60
water content/%
flocculant
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Figure 8. Floccuent effect of some flocculant
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4. Conclusions
Starch, 2-Trimethylammonium ethyl methacrylate chlo-
ride (DMC) and acrylamide (AM) used as raw material
and potassium persulfate as initiator to prepare a
starch-based cation copolymer flocculant. For high-
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starch-based cation copolymer flocculant flocculation
was significantly better than that of the other coagulant in
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5. Acknowledgements
This paper is supported by National Hi-Tech Research
and Development Program of China (863 Program)
(2008BAC43B02).