US2009251128A1PendingUtilityA1
Method and System for Measuring the Zeta Potential Of the Cylinder's Outer Surface and the Inside Surface of the Tube
Est. expirySep 12, 2026(~0.1 yrs left)· nominal 20-yr term from priority
G01N 27/42
55
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Claims
Abstract
The present invention discloses methods and systems for measuring the zeta potential of the cylinder's outer surface and the inside surface of the tube. In the measuring cell for measuring the zeta potential of the cylinder's outer surface, the cylinder is placed coaxially inside the reference tube, and the channel existing between the cylinder and the reference tube forms a annular flow channel. Additionally, in the measuring cell for measuring the inside surface of the tube, a reference cylinder is held coaxially inside the tube and a given solution is forced to flow through the annular space between the tube and the reference cylinder.
Claims
exact text as granted — not AI-modified1 . A method for measuring the zeta potential at inside surface of the tube, comprising:
providing a tube having a first radius and a reference cylinder having a second radius, wherein the first radius is greater than the second radius, and the reference cylinder is held coaxially inside the tube, and the channel existing between the tube and the reference cylinder forms an annular flow channel; introducing a solution to the annular flow channel, and the solution is forced by a pressure difference ΔP to flow through the annular flow channel, wherein the flow direction of the solution is parallel to the axial direction of the reference cylinder; performing a measuring process to measure the streaming potential difference Ē between the two ends of the annular flow channel by electrodes, wherein the measuring process comprises calculating the zeta potential ξ m at inside surface of the tube from the following equation:
E
_
Δ
P
==
-
D
μ
k
m
(
ζ
m
+
ζ
ref
2
)
F
where D is the permittivity, ζ ref is the zeta potential of the reference cylinder, μ is the viscosity of the solution, k is the electric conductivity of the solution, and F is a correction factor for the electrokinetic model.
2 . The method according to claim 1 , wherein the radius of the tube is at greater than millimeter scale.
3 . The method according to claim 1 , wherein the surface of the reference cylinder is substantially smooth.
4 . The method according to claim 1 , wherein the measuring process further comprises measuring the electric conductivity k of the solution.
5 . The method according to claim 1 , wherein the measuring process further comprises measuring the pH value of the solution.
6 . The method according to claim 1 , wherein the correction factor F has a general expression as the following:
F
=
2
(
ζ
ref
ζ
m
)
+
1
+
1
-
ζ
m
ζ
ref
1
+
ζ
m
ζ
ref
×
b
2
-
1
-
2
b
2
·
ln
b
ln
b
·
(
1
-
b
2
)
-
4
·
[
I
1
(
λ
)
-
b
·
I
1
(
λ
b
)
]
λ
·
(
1
-
b
2
)
·
(
1
+
ζ
m
ζ
ref
)
×
[
K
0
(
λ
)
-
ζ
m
ζ
ref
·
K
0
(
λ
b
)
I
0
(
λ
b
)
·
K
0
(
λ
)
-
K
0
(
λ
b
)
·
I
0
(
λ
)
]
-
4
·
[
b
·
K
1
(
λ
b
)
-
K
1
(
λ
)
]
λ
·
(
1
-
b
2
)
·
(
1
+
ζ
m
ζ
ref
)
×
[
ζ
m
ζ
ref
·
I
0
(
λ
b
)
-
I
0
(
λ
)
I
0
(
λ
b
)
·
K
0
(
λ
)
-
K
0
(
λ
b
)
·
I
0
(
λ
)
]
Where
b
=
R
1
/
R
2
,
λ
=
R
2
/
1
κ
,
κ (reciprocal Debye length) can be treated as the reciprocal of the thickness of the electric double layer, I 0 and I 1 are the zero-order and first order modified Bessel functions of first kind, respectively, and, K 0 and K 1 are the zero-order and first order modified Bessel functions of second kind, respectively.
7 . A system for measuring the zeta potential at inside surface of the tube, comprising:
a feeding module; a measurement module comprising a reference cylinder and a tube, wherein the reference cylinder is held coaxially inside the tube, and the radius of the tube is greater than the radius of reference cylinder, and the zeta potential of reference cylinder is known or measured in advance, wherein the measurement module receives a solution from the feeding module, the solution is forced to flow through an annular flow channel between the reference cylinder and the tube, and then the solution is discharged to a discharging module so as to form a measuring course, and thus the measurement module generates a potential difference signal via the measuring course; at least one pressure detector for measuring the pressure difference for solution flow from the inlet to the outlet of the annular flow channel to generate a pressure difference signal; and a calculation module, comprising calculating the zeta potential ξ m at inside surface of the tube:
E
_
Δ
P
==
-
D
μ
k
(
ζ
m
+
ζ
ref
2
)
F
where D is the permittivity, ζ ref is the zeta potential of the reference cylinder, μ is the viscosity of the solution, k is the electric conductivity of the solution, and F is a correction factor for the electrokinetic model, the calculation module receives the potential difference signal and the pressure difference signal accompanying with the zeta potential ξ ref of the reference cylinder which is known or measured in advance to calculate the zeta potential ξ m at inside surface of the tube.
8 . The method according to claim 7 , wherein the radius of the tube is at greater than millimeter scale.
9 . The system according to claim 7 , wherein the surface of the reference cylinder is substantially smooth.
10 . The system according to claim 7 , wherein the reference cylinder is a solid object or the two ends of the reference cylinders are sealed, so as to prevent the solution from flowing through the reference cylinder to affect the measurement result.
11 . The system according to claim 7 , wherein the measurement module further comprises a first detector for measuring the streaming potential at the inlet of the flow channel, and a second detector for measuring the streaming potential at the outlet of the flow channel, so as to generate the potential difference signal.
12 . The system according to claim 7 , wherein the correction factor F has a general equation as the following:
F
=
2
(
ζ
ref
ζ
m
)
+
1
+
1
-
ζ
m
ζ
ref
1
+
ζ
m
ζ
ref
×
b
2
-
1
-
2
b
2
·
ln
b
ln
b
·
(
1
-
b
2
)
-
4
·
[
I
1
(
λ
)
-
b
·
I
1
(
λ
b
)
]
λ
·
(
1
-
b
2
)
·
(
1
+
ζ
m
ζ
ref
)
×
[
K
0
(
λ
)
-
ζ
m
ζ
ref
·
K
0
(
λ
b
)
I
0
(
λ
b
)
·
K
0
(
λ
)
-
K
0
(
λ
b
)
·
I
0
(
λ
)
]
-
4
·
[
b
·
K
1
(
λ
b
)
-
K
1
(
λ
)
]
λ
·
(
1
-
b
2
)
·
(
1
+
ζ
m
ζ
ref
)
×
[
ζ
m
ζ
ref
·
I
0
(
λ
b
)
-
I
0
(
λ
)
I
0
(
λ
b
)
·
K
0
(
λ
)
-
K
0
(
λ
b
)
·
I
0
(
λ
)
]
Where
b
=
R
1
/
R
2
,
λ
=
R
2
/
1
κ
,
κ (reciprocal Debye length) can be treated as the reciprocal of the thickness of the electric double layer, I 0 and I 1 are the zero-order and first order modified Bessel functions of first kind, respectively, and, K 0 and K 1 are the zero-order and first order modified Bessel functions of second kind, respectively.Join the waitlist — get patent alerts
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