CN103884629B - A kind of test apparatus and method for liquid infiltration pressure - Google Patents

Abstract

The invention discloses a test device and method for liquid osmotic pressure. The test device includes a penetration part, a liquid addition part, a mirror part and a pressurization part. Add the liquid to be tested from the liquid feeding part to the permeation part, the reference liquid permeates through the membrane and mixes with the liquid to be tested and then enters the mirror part, and the gas is delivered by the pressurizing part to keep the liquid level at the mirror part for a period of time, then read the pressure value to obtain the osmotic pressure value. The invention provides a novel testing method and device for testing the osmotic pressure, which can effectively test the osmotic pressure while also considering the influence of the concentration polarization.

Description

A testing device and method for liquid osmotic pressure

technical field

The invention relates to a device and method for testing liquid osmotic pressure.

Background technique

At present, membrane water treatment technology plays an increasingly important role in the water treatment process. In recent years, forward osmosis membrane water treatment technology has been used in seawater desalination, Salt water desalination, sewage treatment, power generation, drug release and other fields have broad application prospects, and forward osmosis technology has been widely studied and valued by countries all over the world. In the forward osmosis process, the osmotic pressure of the solution is the driving force of the process, and the size of the osmotic pressure determines the treatment efficiency of the forward osmosis process. Therefore, the device and method of the osmotic pressure test are of great significance for the selection of the draw solution in the forward osmosis process.

Existing osmotic pressure test methods are mainly compiled into software through theoretical calculations, and the calculation results have a certain deviation from the real osmotic pressure of the solution. Therefore, it is still necessary to provide a device and method for testing liquid osmotic pressure in this field. , can accurately and effectively test the osmotic pressure of liquid.

Contents of the invention

The object of the present invention is to provide a device and method for testing liquid osmotic pressure.

A first aspect of the present invention provides an osmotic pressure testing device, the device comprising:

An osmosis tank, the inside of the osmosis tank is equipped with a membrane, and the membrane divides the inside of the osmosis tank into a first chamber and a second chamber;

A liquid adding part, through which the liquid to be tested is added to the first chamber of the permeation cell;

A mirror part, the mirror part is arranged on the upper end of the permeation tank, and has a first through hole inside, the diameter of the first through hole is 1mm-5mm, one end of the first through hole is connected to the permeate the first chamber of the pool communicates; and

A pressurizing part, the pressurizing part includes a pressure buffer chamber, a pressure gauge, and a gas delivery part, wherein the pressure buffer chamber is arranged at the upper end of the mirror part, and the other end of the first through hole is connected to the pressure buffer chamber. The buffer chamber communicates; the gas delivery part communicates with the pressure buffer chamber, and is used to deliver gas into the pressure buffer chamber; the pressure gauge is connected to the pressure buffer chamber, and is used to detect the pressure in the pressure buffer chamber the pressure of the gas.

In another preferred example, the osmosis pool includes a first shell and a second shell oppositely arranged, and the membrane is arranged between the first shell and the second shell to divide the osmosis pool into a second shell. a chamber and a second chamber, wherein,

There is an opening in the middle of the first housing, and a first sealing element is arranged on the surface opposite to the second housing;

The second shell includes a first beam, a second beam, and a first longitudinal rib connected between the first beam and the second beam; the second shell has a second through hole through which the The first beam, the first longitudinal rib, and the second beam communicate with the first cavity and the first through hole; a liquid filling port is arranged on the first beam, and the liquid to be measured passes through the liquid filling port. The mouth is connected to the first chamber by the liquid filling part; the first beam is connected to the first housing through a first connecting piece, and the surface of the first beam is opposite to the first housing A second sealing element is provided on it.

In another preferred example, the first beam, the first longitudinal rib and the second beam are integrally formed.

In another preferred example, the first casing and the second casing are made of stainless steel.

In another preferred example, the opening constitutes a second chamber.

In another preferred example, a groove is engraved on a surface of the first beam opposite to the first housing, and the groove forms the first chamber.

In another preferred example, the first beam is connected to the first housing by a flange.

In another preferred example, the first connecting member is a bolt.

In another preferred example, the osmosis tank further includes a support, and the support is arranged between the membrane and the first shell and/or the second shell.

In another preferred example, the support member is a stainless steel mesh.

In another preferred example, the pressure buffer chamber includes an upper cover and a base plate, the inner cavity formed by the upper cover and the base plate is used for filling gas, and the base plate is arranged on the mirror part the upper end, and the base plate is provided with a third through hole, the two ends of the third through hole communicate with the first through hole and the cavity respectively, and the base plate and the second beam pass through The second connector is connected.

In another preferred example, the pressure buffer chamber is made of stainless steel.

In another preferred example, the upper cover and the base plate are integrally formed.

In another preferred example, the second connecting member is a bolt.

In another preferred example, the mirror part is a glass column with a first through hole inside, and the glass column has one or more of the following features:

(i) the diameter of the glass column is 1cm-20cm;

(ii) the pressure range of the glass column is 100-200 atmospheres;

(iii) There are graduation marks on the glass column.

In another preferred example, the gas delivery unit includes:

The gas holding part is used to hold gas;

The gas delivery pipe includes a gas supply pipe and a gas discharge pipe. The gas supply pipe is used to transport the gas from the gas containing part to the pressure buffer chamber. The gas supply pipe is provided with a tee to connect the gas discharge pipe. The gas in the pressure buffer chamber is released.

In another preferred example, a ball valve is arranged on the air release pipe; a gas regulating valve and a ball valve are arranged in sequence on the air supply pipe.

In another preferred example, the arrangement of the exhaust pipe, the air intake pipe and the valves can also provide pressure balance for the system.

Open and close the ball valve for ventilation or stop ventilation.

The gas regulating valve is used to regulate the flow rate of the incoming gas.

In another preferred example, the liquid addition part includes a liquid addition pipe, the liquid addition pipe communicates with the first chamber of the osmosis cell, and a valve is arranged on the liquid addition pipe.

In another preferred embodiment, the valve is opened when adding liquid, and the liquid to be tested is added to the first chamber of the permeation cell, and the valve is tightened after the liquid is added to maintain the sealing of the system.

In another preferred example, the membrane is a forward osmosis membrane.

A second aspect of the present invention provides a method for testing osmotic pressure, using the device described in the first aspect, comprising the following steps:

(a) the membrane is placed inside the osmosis tank, and the osmosis tank is sealed to prevent leakage;

(b) adding the liquid to be tested into the first cavity of the osmosis cell through the liquid adding part;

(c) placing the osmosis cell in a reference liquid, the reference liquid passes through the second chamber of the osmosis cell, and the membrane enters the first chamber of the osmosis cell to form a mixed solution with the liquid to be tested, and into the first through hole;

(d) when the mixed solution reaches the set position of the first through hole, the gas delivery part delivers gas to the pressure buffer chamber to maintain the mixed solution at the set position;

(e) The mixed solution is maintained at the set position for 0.5-2h, and the pressure value on the pressure gauge is read, and the sum of the osmotic pressure of the reference liquid and the osmotic pressure of the liquid to be tested is the osmotic pressure of the liquid to be tested.

In another preferred example, the gas is nitrogen, helium, argon, or oxygen.

In another preferred example, the membrane is a forward osmosis membrane, a polymer film that only allows one kind of molecule (solvent molecule) to pass through, while other ions and molecules cannot pass through.

In another preferred example, the reference liquid is the corresponding solvent of the test liquid.

In another preferred example, the reference liquid refers to a liquid with an osmotic pressure of 0 relative to the test liquid, which serves as a benchmark for testing the osmotic pressure of the test liquid.

The invention provides a novel device and method for measuring liquid osmotic pressure, which can not only measure liquids with low osmotic pressure (such as ≤1 atmospheric pressure), but also measure liquids with high osmotic pressure (such as 10-900 atmospheric pressure) . The device of the present invention considers the influence of the concentration polarization phenomenon of the membrane while detecting the osmotic pressure of the liquid, and is easy to operate, and the osmotic pressure value can be obtained by directly reading the value of the pressure gauge after the liquid level reaches equilibrium for about half an hour .

It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described in the following (such as embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, we will not repeat them here.

Description of drawings

Fig. 1 is a schematic structural view of the test device of the present invention.

detailed description

After extensive and in-depth research, the inventor of the present application accidentally developed a device and method for testing liquid osmotic pressure for the first time, using the liquid movement generated by the driving force generated by the osmotic pressure difference between solutions to perform related tests, which can directly The osmotic pressure of the liquid is tested on the pressure gauge, and the method is simple and accurate. On this basis, the present invention has been accomplished.

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. For the experimental methods without specific conditions indicated in the following examples, usually follow the conventional conditions or the conditions suggested by the manufacturer. Percentages and parts are by weight unless otherwise indicated.

Osmotic Pressure Test Device

As shown in Figure 1, the osmotic pressure testing device of the present invention comprises:

An osmosis tank 1, the inside of the osmosis tank 1 is equipped with a membrane 2, and the membrane 2 divides the inside of the osmosis tank 1 into a first chamber 3 and a second chamber 4;

A liquid addition part 5, through which the liquid to be tested is added to the first cavity 3 of the permeation cell 1;

Mirror part 6, the mirror part 6 is arranged on the upper end of the permeation tank 1, and has a first through hole 7 inside, the diameter of the first through hole 7 is 1mm-5mm, the first through hole 7 One end communicates with the first chamber 3 of the osmosis pool 1;

A pressurizing part 8, the pressurizing part 8 includes a pressure buffer chamber 9, a pressure gauge 10, and a gas delivery part 11, wherein the pressure buffer chamber 9 is arranged at the upper end of the mirror part 6, and the first through hole The other end of 7 communicates with the pressure buffer chamber 9; the gas delivery part 11 communicates with the pressure buffer chamber 9 for delivering gas into the pressure buffer chamber 9; the pressure gauge 10 is connected to the The pressure buffer chamber 9 is used to detect the pressure of the gas in the pressure buffer chamber 9 .

In a preferred example, the membrane 2 is a polymer water treatment membrane.

In a preferred example, the membrane 2 is a forward osmosis membrane. Forward osmosis refers to the process in which water flows from the higher water chemical potential (or lower osmotic pressure) side area to the lower water chemical potential (or higher osmotic pressure) side area through the selectively permeable membrane. The selectively permeable membrane used in this process is the forward osmosis membrane. The device of the present invention has no special limitation on the forward osmosis membrane, and can use various commercially available or laboratory-prepared forward osmosis membranes, such as commonly used cellulose diacetate forward osmosis membranes, cellulose triacetate forward osmosis membranes, or Polyamide forward osmosis membrane, etc.

In a preferred example, the osmosis tank 1 includes a first shell 12 and a second shell 13 oppositely arranged, the membrane 2 is arranged between the first shell 12 and the second shell 13, and the The permeation tank 1 is divided into a first chamber 3 and a second chamber 4, wherein,

The middle part of the first housing 12 has an opening 14, and a first sealing element 20 is provided on the surface of the first housing 12 opposite to the second housing 13;

The second housing 13 includes a first beam 15, a second beam 16, and a first longitudinal rib 17 connected between the first beam 15 and the second beam 16; the second housing 13 has The second through hole 18 runs through the first beam 15, the first longitudinal rib 17, and the second beam 16, and communicates with the first cavity 3 and the first through hole 7; Liquid filling port 19, the liquid to be tested is added to the first cavity 3 from the liquid filling part 5 through the liquid filling port 19; the first crossbeam 15 and the first housing 12 pass through the first A connecting piece (not shown in the figure) is connected, and a second sealing element 21 is disposed on a surface of the first beam 15 opposite to the first casing 12 .

In another preferred example, the first beam 15, the first longitudinal rib 17, and the second beam 16 are integrally formed.

In another preferred example, the first casing 12 and the second casing 13 are made of stainless steel.

In another preferred example, the opening 14 constitutes the second cavity 4 .

In another preferred example, a groove (not shown) is engraved on the surface of the first beam 15 opposite to the first housing 12 , and the groove forms the first cavity 3 .

In another preferred example, the first beam 15 is connected to the first housing 12 by a flange.

In another preferred example, the first sealing element 20 and the second sealing element 21 are sealing rings.

In another preferred example, the first connecting member is a bolt.

In another preferred example, the osmosis tank 1 further includes a supporting member 22 , and the supporting member is arranged between the membrane 2 and the first casing 12 and/or the second casing 13 .

In another preferred example, the support member 22 is a stainless steel mesh, which is arranged between the membrane 2 and the first casing 12 .

In another preferred example, the support member 22 is a stainless steel screen, which is arranged between the membrane 2 and the first beam 15 .

In a preferred example, the mirror part 6 is a glass column with a first through hole 7 inside, and the glass column has one or more of the following features:

(i) the diameter of the glass column is 1cm-20cm;

(ii) the pressure range of the glass column is 100-200 atmospheres;

(iii) There are graduation marks on the glass column.

In another preferred example, the diameter of the glass column is 2cm-10cm.

The sight glass part is made of a pressure-bearing glass column with scales, and has a first through hole 7 inside, so that the movement of the liquid can be observed, and the level of the liquid can be used to monitor the osmotic pressure of the solution.

In a preferred example, the pressure buffer chamber 9 includes an upper cover 23 and a base plate 24, the inner cavity 25 formed by the upper cover 23 and the base plate 24 is used for filling gas, and the base plate 24 is set A third through hole 26 is arranged on the upper end of the mirror part 6 and on the base plate 24, and the two ends of the third through hole 26 communicate with the first through hole 7 and the cavity 25 respectively, And the base plate 24 is connected to the second beam 16 through a second connecting piece (not shown).

In another preferred example, the pressure buffer chamber 9 is made of stainless steel.

In another preferred example, the upper cover 23 and the base plate 24 are integrally formed.

In another preferred example, the second connecting member is a bolt.

In a preferred example, the gas delivery unit 11 includes:

A gas containing part (not shown in the figure) is used for containing gas;

The gas delivery pipe includes a gas supply pipe 28 and a gas discharge pipe 29. The gas supply pipe 28 is used to transport gas from the gas containing part to the pressure buffer chamber 9. The gas supply pipe 28 is provided with a tee 30, The air release pipe 29 is connected to release the gas in the pressure buffer chamber 9 .

In another preferred example, the gas is nitrogen, helium, argon, or oxygen.

In another preferred example, a ball valve 31 is arranged on the air release pipe 29 ; a gas regulating valve 32 and a ball valve 33 are arranged on the air delivery pipe 28 in sequence.

Open and close ball valves 31, 33 for ventilation or stop ventilation.

The gas regulating valve 32 is used to regulate the flow rate of the incoming gas.

The setting of deflation pipe 29, intake pipe 28, and each valve can provide pressure balance for the system. The liquid level in the first through hole is controlled at a certain height through the pressure control of the gas, and the liquid level reaches equilibrium when the gas flow is adjusted through various valves, so as to measure the osmotic pressure of the solution.

In a preferred example, the liquid addition part 5 includes a liquid addition pipe 34 , the liquid addition pipe 34 communicates with the first cavity 3 of the permeation cell 1 , and a valve 35 is arranged on the liquid addition pipe 34 .

Open the valve 35 when adding liquid, add the liquid to be tested into the first chamber 3 of the permeation cell 1, and tighten the valve 35 after the liquid is added to maintain the tightness of the system.

Osmolality Test Method

Osmotic pressure testing method of the present invention, adopts above-mentioned device, comprises the following steps:

(a) The membrane 2 is placed inside the osmosis tank 1, and the osmosis tank 1 is sealed to prevent leakage;

(b) adding the liquid to be tested into the first cavity 3 of the permeation cell 1 through the liquid adding part 5;

(c) The osmosis cell 1 is placed in a reference liquid, and the reference liquid enters the first cavity 3 of the osmosis cell 1 through the second chamber 4 of the osmosis cell 1 and the membrane 2 to be tested. The liquid forms a mixed solution and enters into the first through hole 7;

(d) When the mixed solution reaches the set position of the first through hole 7, the gas delivery part 11 delivers gas to the pressure buffer chamber 9 to maintain the mixed solution at the set position;

(e) The mixed solution is maintained at the set position for 0.5-2h, and the pressure value on the pressure gauge 10 is read. The sum of the pressure value and the osmotic pressure of the reference liquid is the osmotic pressure of the liquid to be tested.

In another preferred example, the gas is nitrogen, helium, argon, or oxygen.

In another preferred example, the membrane 2 is a forward osmosis membrane, a polymer film that only allows one type of molecule (solvent molecule) to pass through, while other ions and molecules cannot pass through.

In another preferred embodiment, the reference liquid is a solvent corresponding to the liquid to be tested, such as water.

In another preferred embodiment, the reference liquid refers to a liquid having an osmotic pressure of 0 relative to the liquid to be tested, which serves as a benchmark for testing the osmotic pressure of the test liquid.

In another preferred example, the set position is a position where the liquid level is expected to be set by the tester in the mirror before the measurement, such as the middle position of the first through hole 7 .

In another preferred example, when the device of the present invention is used to detect the osmotic pressure, the membrane 2 is placed inside the osmotic cell 1, and the supporting member 22 is located on the upper and lower surfaces of the membrane, between the membrane 2 and the first housing 12, Between the membrane and the first beam 15 of the second housing 13, a first connecting member is used to connect the first beam 15 and the first housing 12, and under the action of the first sealing element 20 and the second sealing element 21, the The first chamber 3 is formed as a sealed space. Open the valve 35 of the liquid adding part 5 to inject the liquid to be tested into the first cavity 3 of the permeation cell 1 and onto the membrane 2 . After adding liquid, close the valve 35 to keep the tightness of the permeation tank 1. After the device is sealed, the osmotic cell 1 is placed in a container filled with a reference liquid (such as deionized water). Because the osmotic pressure on both sides of the membrane 2 is different, the reference liquid enters the second through the opening 14 of the first housing 12. The chamber 4 enters the first chamber 3 through the membrane 2 to mix with the liquid to be tested, and then enters the first through hole 7 of the mirror part 6 through the second through hole 18 . When the liquid level reaches the setting position of the first through hole 7 (such as the middle part of the first through hole 7), slowly open the ball valve 33 on the gas delivery pipe 28 of the gas delivery part 11, and the gas is delivered to the pressure buffer chamber 9, and Enter the first through hole 7 to the liquid surface through the third through hole 26, and at the same time adjust the gas regulating valve 32 on the air delivery pipe 28 to keep the liquid level at the set position, read the pressure value of the pressure gauge 10 after 30 minutes, and set The pressure value is added to the osmotic pressure of the reference liquid to obtain the osmotic pressure of the liquid to be measured.

Application Example 1

Using deionized water as a reference solution, test the osmotic pressure of 35000mg.L ^-1 NaCl solution. Use cellulose diacetate permeable membrane as the test membrane, fix it in the permeation cell and seal it, add 10ml of the solution to be tested to the first chamber through the liquid adding part, seal the device well, and place it in a horizontal container filled with deionized water After a period of time, the liquid level in the sight mirror rises. When the liquid level rises to the middle of the first through hole, slowly open the gas delivery part to pressurize, while keeping the liquid level in the first through hole at the same At the height, until the pressure reaches a certain value, the liquid level reaches equilibrium. At this time, the pressure indication is 2.7MPa. Because the osmotic pressure of deionized water is 0, the osmotic pressure of the solution to be tested is 2.7MPa.

It is found in the literature that the calculated osmotic pressure of the 35000mg.L ^-1 NaCl solution is 2.8MPa, and the 3.6% error comes from the concentration polarization generated by the osmotic membrane during the osmotic process, as well as some errors in the test device itself and Some human errors are within the acceptable range.

Application Example 2

Using deionized water as a reference solution, test the osmotic pressure of 1000 mg.L ^-1 sucrose solution. Use polyamide permeable membrane as the test membrane, fix it in the permeation cell and seal it, add 10ml of the solution to be tested on it, seal the device well, and place it in a horizontal container filled with deionized water. After a period of time, the sight glass When the liquid level rises to the middle of the first through hole, slowly open the gas delivery part to pressurize, while keeping the liquid level in the first through hole at the same height until the pressure reaches a certain level. After a value, the liquid level reaches equilibrium. At this time, the pressure indication number is 0.0029MPa. Because the osmotic pressure of deionized water is 0, the osmotic pressure of the solution to be tested is 0.0029MPa.

The calculated osmotic pressure of 35,000 mg.L ^-1 NaCl solution found in the literature is 0.00292 MPa, and the error comes from the concentration polarization generated by the osmotic membrane during the osmotic process, as well as some errors in the test device itself and some human errors , and its error is within the acceptable range.

Unless otherwise defined, all professional and scientific terms used herein have the same meanings as commonly understood by those skilled in the art. In addition, any methods and materials similar or equivalent to those described can be applied to the method of the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only.

The benefits of the present invention are:

(1) A novel device and method for measuring liquid osmotic pressure are provided.

(2) The device of the present invention can not only measure liquids with low osmotic pressure (such as ≤1 atmospheric pressure), but also can measure liquids with high osmotic pressure (such as 10-900 atmospheric pressure).

(3) The device of the present invention takes into account the influence of the concentration polarization phenomenon of the membrane while detecting the osmotic pressure of the liquid.

(4) The device of the present invention is easy to operate, and the value of the pressure gauge can be directly read or the osmotic pressure value can be obtained after the liquid level reaches equilibrium for about half an hour.

All documents mentioned in this application are incorporated by reference in this application as if each were individually incorporated by reference. In addition, it should be understood that after reading the above teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (1)

1. an osmotic pressure testing method, is characterized in that, adopts a kind of osmotic pressure testing device, and this osmotic pressure testing device comprises: An osmosis tank, the inside of the osmosis tank is equipped with a membrane, and the membrane divides the inside of the osmosis tank into a first chamber and a second chamber; A liquid adding part, through which the liquid to be tested is added to the first chamber of the permeation cell; A mirror part, the mirror part is arranged on the upper end of the permeation tank, and has a first through hole inside, the diameter of the first through hole is 1mm-5mm, one end of the first through hole is connected to the permeate the first chamber of the pool communicates; and A pressurizing part, the pressurizing part includes a pressure buffer chamber, a pressure gauge, and a gas delivery part, wherein the pressure buffer chamber is arranged at the upper end of the mirror part, and the other end of the first through hole is connected to the pressure buffer chamber. The buffer chamber communicates; the gas delivery part communicates with the pressure buffer chamber, and is used to deliver gas into the pressure buffer chamber; the pressure gauge is connected to the pressure buffer chamber, and is used to detect the pressure in the pressure buffer chamber gas pressure, The osmotic pressure test method comprises the following steps: (a) placing the membrane inside the osmosis tank, sealing the osmosis tank to prevent leakage; (b) adding the liquid to be tested into the first chamber of the osmosis cell through the liquid adding part; (c) placing the osmosis cell in a reference liquid, the reference liquid passes through the second chamber of the osmosis cell, and the membrane enters the first chamber of the osmosis cell to form a mixed solution with the liquid to be tested, and into the first through hole; (d) when the mixed solution reaches the set position of the first through hole, the gas delivery part delivers gas to the pressure buffer chamber to maintain the mixed solution at the set position; (e) The mixed solution is maintained at the set position for 0.5-2h, and the pressure value on the pressure gauge is read, and the sum of the osmotic pressure of the reference liquid and the osmotic pressure of the liquid to be tested is the osmotic pressure of the liquid to be tested.