SYSTEM AND PROCESS FOR DETERMINING AND ANALYSING SURFACE PROPERTY PARAMETERS OF SUBSTANCE BASED ON KINETIC METHOD

• US 20150076006A1
• Filed: 01/20/2012
• Published: 03/19/2015
• Est. Priority Date: 11/24/2011
• Status: Active Grant

• Current Assignee: Southwest University
• Original Assignee: Southwest University
• Inventors: Li, Rui, Li, Hang, Liu, Xinmin, Li, Zhenlun, Hou, Jie, Zhu, Hualing, Wu, Laosheng
• Granted Patent: US 9,719,953 B2
• Time in Patent Office: Days
• US Class Current: 205/789
• CPC Class Codes: G01N 27/26 by investigating electrochemical variables; by using electrolysis or electrophoresis
• CPC Class Codes: G01R 29/24 Arrangements for measuring quantities of charge

Abstract

A system and process for determining and analyzing surface property parameters of a substance based on kinetic method is provided. The system comprises a sample processing system and a detection system. The sample processing system includes a reactor (3), a collector for liquid to be tested (5), and a container for liquid to be tested (6). The detection system includes a detecting electrode (13), a concentration and activity operator, a kinetic data processor, a surface property operation module, and a result output module. The process comprises: having the substance to be tested to be treated with an electrolyte solution, measuring activity of liquid to be tested upon reaction at a pre-set time interval, and processing with the kinetic data processor and the surface property operation module, so as to obtain surface property parameters of the substance to be tested. The present invention adopts kinetic method of ion exchange to overcome the issues associated with long reaction equilibrium time, not easy to determine equilibrium and not easy to accurately determine the value of m. Five parameters of the substance surface property can be calculated with only intercept and gradient of the linear regression equation obtained from the kinetic data, and the total amount of surface charge can also be directly determined.

Claims

1. A system for determining and analyzing surface property parameters of a substance based on kinetic method, comprising a sample processing system and a detection system;

the sample processing system including a reactor, a collector for liquid to be tested and a container for liquid to be tested;

the reactor is used for containing the substance to be tested and reaction liquid;

the reactor is connected with the collector for liquid to be tested via a conduit;

the collector for liquid to be tested is connected with the container for liquid to be tested via a conduit;

the reaction liquid in the reactor flows into the collector for liquid to be tested;

the liquid in the collector for liquid to be tested flows into the container for liquid to be tested;

the detection system including a detecting electrode, a concentration and activity operator, a kinetic data processor, a surface property operation module, and a result output module;

the detecting electrode is used for detecting an ion activity of solution in a sample container;

the concentration and activity operator is used for calculating concentration of the solution based on the ion activity obtained from the detecting electrode;

the kinetic data processor is used for processing and storing data obtained from detecting and establishes a linear regression equation to obtain intercept and gradient of a line;

the surface property operation module is used for calculating the surface property parameters of the substance based on detected data;

the result output module is used for outputting the surface property parameters of the substance;

the detecting electrode, the operator concentration and activity, the kinetic data processor, the surface property operation module, and the result output module are connected in order.

2. The system for determining and analyzing surface property parameters of a substance based on kinetic method according to claim 1, wherein:

the surface property operation module comprises a surface charge total amount operator, a surface potential operator, a surface charge density operator, a surface electric field intensity operator, and a specific surface area operator;

the kinetic data processor is connected with the surface charge total amount operator and the surface potential operator;

the surface potential operator is connected with the surface charge density operator;

the surface charge density operator is connected with the surface electric field intensity operator;

the surface charge density operator and the surface charge total amount operator are connected with the specific surface area operator;

the result output module is respectively connected with the surface charge total amount operator, the surface potential operator, the surface charge density operator, the surface electric field intensity operator, and the specific surface area operator.

3. The system for determining and analyzing surface property parameters of a substance based on kinetic method according to claim 1, wherein:

the kinetic data processor establishes the linear regression equation through the following steps, to obtain the intercept and gradient of the line;

S1;

y-coordinate is y=[N_B(t_i+1)−

N_B(t_i)]/(t_i+1−

t_i),

x-coordinate is x=N_B(t_i)+0.5[N_B(t_i+1)−

N_B(t_i)];

S2;

drawing a line image based on x-coordinate and y-coordinate in a rectangular coordinate system;

S3;

obtaining the intercept p and gradient q of the line;

wherein, N_B(t_i) represents an accumulated adsorption amount of ion B^m+, N_B(t_i) is the accumulated adsorption amount of the sample to ion B^m+ upon reaction for t=t_i minutes, t₀ is a pre-set time interval, and t_i is a reaction time.

4. The system for determining and analyzing surface property parameters of a substance based on kinetic method according to claim 3, further comprising:

a millivoltmeter, a constant flow pump, a liquid container, a constant temperature chamber and a thermostat;

an input port of the millivoltmeter is connected with the detecting electrode;

an output port of the millivoltmeter is connected with the concentration and activity operator;

the constant flow pump is positioned between the reactor and the collector for liquid to be tested, for controlling liquid flow velocity from the reactor to the collector for liquid to be tested;

further comprising;

a first control valve, a second control valve, a third control valve, an automatic controller for valve and a negative pressure pump;

the first control valve is positioned between the collector for liquid to be tested and the container for liquid to be tested;

the container for liquid to be tested is provided with the second control valve that is connected with the negative pressure pump;

the container for liquid to be tested is further provided with the third control valve that is connected with the negative pressure pump;

the third control valve and the negative pressure pump are provided with a waste liquid discharge outlet for draining liquid from the container for liquid to be tested;

the automatic controller for valve is connected with the first control valve, the second control valve and the third control valve, respectively;

the thermostat is connected with the constant flow pump;

the liquid container is connected with the reactor; and

, the sample processing system is positioned within the constant temperature chamber.

5. The system for determining and analyzing surface property parameters of a substance based on kinetic method according to claim 2, wherein:

the surface charge total amount operator calculates the total amount of surface charge of the substance to be tested with the following equation;

6. The system for determining and analyzing surface property parameters of a substance based on kinetic method according to claim 2, wherein:

the surface potential operator calculates the surface potential of the substance to be tested with the following equation;

7. A process according to the system for determining and analyzing surface property parameters of a substance based on kinetic method of claim 1, comprising the following steps:

S1;

performing Aⁿ⁺ saturation to the surface of the substance to be tested with AX_n electrolyte solution having a known concentration;

wherein, the AX_n electrolyte solution represents an electrolyte solution of metallic cation with a charge amount of n, and ion A⁺ represents a metallic cation with a charge amount of n;

S2;

having a BX_m electrolyte solution with a known concentration to flow through the surface of the substance to be tested, to have fusion replacement occurred between ion Aⁿ⁺ and ion B^m+ on the surface of the substance to be tested;

wherein, BX_m electrolyte solution represents an electrolyte solution of a metallic cation with a charge amount of m, and ion B^m+ represents a metallic cation with a charge amount of m;

S3;

collecting liquid that flows out from the surface of the substance to be tested at the pre-set time interval;

S4;

determining an activity of ion B^m+ in the flow-out liquid, and calculating an concentration of ion B^m+;

S5;

using the concentration of ion B^m+ to calculate an accumulated adsorption amount of ion B^m+ according to the following equation;

8. The process of claim 7, wherein:

step S4 further comprises the following steps;

S41;

having BX_m electrolyte solution with a known concentration to flow through the surface of the substance to be tested, to have fusion replacement occurred between ion Aⁿ⁺ and ion B^m+ on the surface of the substance to be tested;

mSoil−

A+nBX_m=nSoil−

B+mAX_n;

obtaining a solution having Aⁿ⁺, B^m+ and X⁻

, and calculating concentration of ion Aⁿ⁺ and concentration of ion B^m+;

9. The process of claim 7, further comprising the below steps following step S7:

S8;

calculating ion strength I of the mixed electrolyte flow liquid containing ion Aⁿ⁺ and ion B^m+ according to the following equation;

I=½

[(n+n²)f_A0+(m+m²)f_B0]

wherein, f_A0 is a solution concentration before ion Aⁿ⁺ flows into the surface of the substance to be tested, and f_B0 is a solution concentration before ion B^m+ flows into the surface of the substance to be tested;

S9;

substituting the ion strength of the flow liquid in Davies equation, to calculate ion Aⁿ⁺ activity coefficient γ

_A0 and ion B^m+ activity coefficient γ

_B0;

S10;

respectively calculating activity of ion Aⁿ⁺ and ion B^m+ according to the following equation;

a_A⁰=f_A0γ

_A0 a_B⁰=f_B0γ

_B0

wherein, γ

_A0 and γ

_B0 are respective activity coefficient of ion Aⁿ⁺ and ion B^m+ in bulk solution when reaction reaches equilibrium; and

, a_A⁰ and a_B⁰ are respective activity of ion Aⁿ⁺ and ion B^m+ in bulk solution when reaction reaches equilibrium.

10. The process of claim 9, further comprising the below steps following step S10:

S11;

under a given pH condition, having a mixed electrolyte solution composed by AX_n electrolyte solution with a known concentration f_A0 and BX_m electrolyte solution with a known concentration f_B0 to flow through the surface of the substance to be tested, to have fusion replacement occurred between ion A_n+ and ion B^m+ on the surface of the substance to be tested, and collecting liquid that flows out from the surface of the substance to be tested at the pre-set time interval;

S12;

repeating steps S1 to S6;

S13;

using the accumulated adsorption amount N_B(t_i) of ion B^m+, with y-coordinate as y=[N_B(t_i+1)−

N_B(t_i)]/(t_i+1−

t_i) and corresponding x-coordinate as x=N_B(t_i)+0.5[N_B(t_i+1)−

N_B(t_i)], to draw a line image based on positions of x-coordinate and y-coordinate in a rectangular coordinate system, to obtain intercept p and gradient q of the line.

11. The process of claim 10, further comprising the below steps following step S13:

S14;

substituting the charge total amount obtained from step S7, the activity obtained from step S10, and the intercept p and gradient q of the line obtained from step S13 in the following equation to calculate the surface potential of the substance to be tested;

12. The process of claim 11, further comprising the below steps following step S14:

S15;

substituting the surface potential of the substance to be tested in the following equation to calculate the surface charge density of the substance to be tested;

13. The process of claim 12, further comprising the below steps following step S15:

S16;

substituting the surface charge density of the substance to be tested in the following equation to calculate the surface electric field intensity of the substance to be tested;

14. The process of claim 13, further comprising the below steps following step S16:

S17;

substituting the surface charge total amount and the surface charge density of the substance to be tested in the following equation to obtain the specific surface area of the sample;

15. The process of claim 14, further comprising the below steps following step S17:

S18;

outputting surface parameters of the substance to be tested, the surface parameters includes;

surface potential of the substance to be tested, surface charge total amount of the substance to be tested, surface charge density of the substance to be tested, surface electric field intensity of the substance to be tested, and specific surface area of the substance to be tested.