Method for preparing compound dispersoids of hydrophobic nanoparticles and surfactants

Abstract

An apparatus for preparing compound dispersoids of hydrophobic nanoparticles and surfactants, comprises a water supply pipeline, a compounding mixing pipeline and an aggregating pipeline; the compounding mixing pipeline comprises an ultrasonic dispersion instrument and a liquid storage tank connected in series into a loop, and a second plunger pump allowing unidirectional circulation of materials is arranged between the ultrasonic dispersion instrument and the liquid storage tank; the water supply pipeline is connected to the top of the ultrasonic dispersion instrument; and the aggregating pipeline is connected to a discharge end of the liquid storage tank.

Claims

1. A method for preparing a complex dispersion of hydrophobic nanoparticles and surfactants with a dispersion apparatus, wherein the dispersion apparatus comprises a water supply pipeline, a complex mixing pipeline and a material collecting pipeline; the complex mixing pipeline comprises an ultrasonic disperser and a fluid reservoir that are connected in series, and a first plunger pump for one-way circulation of materials is provided between the ultrasonic disperser and the fluid reservoir; the water supply pipeline is connected with a top of the ultrasonic disperser; the material collecting pipeline is connected with a material outlet of the fluid reservoir; the ultrasonic disperser comprises an instrumental barrel, a first ultrafiltration membrane and a second ultrafiltration membrane are disposed in the instrumental barrel up and down in succession which divide the instrumental barrel into three cavities, which are: a first cavity with a first ultrasonic emission probe disposed therein, a second cavity with a second ultrasonic emission probe disposed therein and a third cavity; a wall of the instrumental barrel is provided with a through surfactant delivery pipe connected to the first cavity; and the wall of the instrumental barrel is provided with a through hydrophobic nanoparticles delivery pipe connected to the second cavity; wherein the method comprises the following steps: (1) the first and second ultrafiltration membranes of suitable aperture sizes are selected according to experimental requirements, the second ultrafiltration membrane is mounted on a second snap ring first, and then the first ultrafiltration membrane is mounted on a first snap ring; (2) a top cap of the ultrasonic disperser is fastened down, surfactants are added into the first cavity of the ultrasonic disperser through the surfactant delivery pipe, and hydrophobic nanoparticles are added into the second cavity of the ultrasonic disperser through the hydrophobic nanoparticle delivery pipe; the surfactant delivery pipe and the hydrophobic nanoparticle delivery pipe are closed after delivery; (3) water in a water reservoir is injected into the ultrasonic disperser by the first plunger pump; (4) after the water is injected, the hydrophobic nanoparticles and the surfactants are enabled to carry out one-way circulation in the complex mixing pipeline by a second plunger pump, and the first and second ultrasonic emission probes are started; during the process of water circulation in the ultrasonic disperser, at first, water is mixed with the surfactants in a upper room of the ultrasonic disperser, a dispersion solution of surfactants and water is formed under ultrasonic cavitation effects of the first ultrasonic emission probe and enters the second cavity through the first ultrafiltration membrane, part of the solution that meets not the standard of the first ultrafiltration membrane size is detained in the first cavity without entering the second cavity until the particle size thereof meets the standard of the first ultrafiltration membrane size after ultrasonic cavitation by the first ultrasonic emission probe; (5) the dispersion solution of surfactants and water entering the second cavity is mixed with the hydrophobic nanoparticles; (6) the complex dispersion of hydrophobic nanoparticles dispersed into suitable sizes and surfactants enters into the third cavity through the second ultrafiltration membrane, and then is cycled to the ultrasonic disperser through the fluid reservoir and the second plunger pump; (7) steps (1) to (6) are repeated and cycled to form the complex dispersion of hydrophobic nanoparticles and surfactants; (8) the complex dispersion of hydrophobic nanoparticles and surfactants is cycled to the fluid reservoir; (9) connection between the material collecting pipeline and the fluid reservoir is enabled, the dispersion is collected to a complex dispersion reservoir by a third plunger pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of an integral structure of an apparatus for preparing compound dispersoids of hydrophobic nanoparticles and surfactants according to the present invention;

(2) FIG. 2 is a top view of a top lid of an ultrasonic dispersion instrument;

(3) FIG. 3 is a top sectional view of the interior of the ultrasonic dispersion instrument;

(4) FIG. 4 is a comparative picture of the compound dispersoids obtained in embodiments 7-10 and the compound dispersoids prepared by conventional methods;

(5) In FIG. 4, a compound dispersoid solution in a test tube No. 1 is prepared by the conventional methods, i.e. concentration of SiO.sub.2 in the compound dispersoids is controlled to be 1%, concentration of AOT is controlled to be 0.4%, and then the final product is prepared by stirring with a magnetic stirrer at a speed of 1000 rpm for 30 min;

(6) In FIG. 4, test tubes No. 2, No. 3, No. 4 and No. 5 correspond to the pictures of the compound dispersoids obtained in embodiments 7-10 respectively.

(7) FIG. 5 is a TEM photomicrograph of the compound dispersoids prepared by conventional methods;

(8) FIG. 6-FIG. 9 are TEM photomicrographs of the compound dispersoids obtained in embodiments 7-10.

(9) In FIG. 1-FIG. 3, 1 is a water supply pipeline, 2 is a compounding mixing pipeline, 3 is an aggregating pipeline, 4 is an ultrasonic dispersion instrument, 5 is a liquid storage tank, 6 is a second plunger pump, 7 is an instrument barrel, 8 is a first ultrafiltration membrane, 9 is a second ultrafiltration membrane, 10 is a first cavity, 11 is a second cavity, 12 is a third cavity, 13 is a first ultrasonic transmitting probe, 14 is a second ultrasonic transmitting probe, 15 is a surfactant delivery pipeline, 16 is a hydrophobic nanoparticle delivery pipeline, 17 is a top lid, 18 is a first snap ring, 19 is a second snap ring, 20 is a water storage tank, 21 is a first plunger pump, 22 is a flow meter, 23 is a compound dispersoid storage tank, 24 is a third plunger pump, 25 is a temperature control apparatus; 26 is a bolt for fixing the top lid, 27 is a seal ring for sealing the top lid, 28 is a valve.

DETAILED DESCRIPTION OF THE INVENTION

(10) Principles, specific structures and preferred embodiments provided by the present invention will be further described with reference to the accompanying drawings, but not limited to it.

Embodiment 1

(11) An apparatus for preparing compound dispersoids of hydrophobic nanoparticles and surfactants comprises a water supply pipeline 1, a compounding mixing pipeline 2 and an aggregating pipeline 3;

(12) the compounding mixing pipeline 2 includes an ultrasonic dispersion instrument 4 and a liquid storage tank 5 connected in series into a loop, and a second plunger pump 6 allowing unidirectional circulation of materials is arranged between the ultrasonic dispersion instrument 4 and the liquid storage tank 5;
the water supply pipeline 1 is connected to the top of the ultrasonic dispersion instrument 4;
and the aggregating pipeline 3 is connected to a discharge end of the liquid storage tank 5.

Embodiment 2

(13) Embodiment 2 differs from the apparatus for preparing compound dispersoids of hydrophobic nanoparticles and surfactants in embodiment 1 in that the ultrasonic dispersion instrument 4 comprises an instrument barrel 7, wherein a first ultrafiltration membrane 8 and a second ultrafiltration membrane 9 are sequentially arranged in the instrument barrel 7 from top to bottom, and divide the instrument barrel into three cavities: a first cavity 10, a second cavity 11 and a third cavity 12, and a first ultrasonic transmitting probe 13 is arranged in the first cavity 10; a second ultrasonic transmitting probe 14 is arranged in the second cavity 11; a surfactant delivery pipeline 15 is arranged on a barrel wall of the instrument barrel 7 in a penetrating manner and communicated with the first cavity 10; and a hydrophobic nanoparticle delivery pipeline 16 is arranged on a barrel wall of the instrument barrel 7 in a penetrating manner and communicated with the second cavity 11.

Embodiment 3

(14) Embodiment 3 differs from the apparatus for preparing compound dispersoids of hydrophobic nanoparticles and surfactants in embodiments 1-2 in that the ultrasonic dispersion instrument includes a movably opened and closed top lid 17.

(15) The inner barrel wall of the said instrument barrel 7 is provided with a first snap ring 18 and a second snap ring 19, and the first ultrafiltration membrane 8 and the second ultrafiltration membrane 9 are respectively erected in the instrument barrel 7 via the first snap ring 18 and the second snap ring 19.

Embodiment 4

(16) Embodiment 4 differs from the apparatus for preparing compound dispersoids of hydrophobic nanoparticles and surfactants in embodiment 1 in that the water supply pipeline 1 is connected to the ultrasonic dispersion instrument 4 and the liquid storage tank 5 via a three-way pipe; the water supply pipeline 1 comprises a water storage tank 20, a first plunger pump 21 and a flow meter 22.

(17) the aggregating pipeline 3 is connected with the liquid storage tank 5 and the ultrasonic dispersion instrument 4 via a three-way pipe; the aggregating pipeline 3 comprises a compound dispersoid storage tank 23 and a third plunger pump 24.

Embodiment 5

(18) Embodiment 5 differs from the apparatus for preparing compound dispersoids of hydrophobic nanoparticles and surfactants in embodiment 4 in that the instrument barrel 7 is overall rectangular, and a temperature control apparatus 25 is provided at the inner side of the barrel wall; a first ultrasonic transmitting probe 13 or a second ultrasonic transmitting probe 14 is respectively arranged on the barrel wall adjacent to the temperature control apparatus 25.

Embodiment 6

(19) Embodiment 6 differs from the apparatus for preparing compound dispersoids of hydrophobic nanoparticles and surfactants in embodiments 1-5 in that a pore size of the first ultrafiltration membrane 8 is 10 nm-100 nm, and a pore size of the second ultrafiltration membrane 9 is 10 nm-100 nm, the first ultrafiltration membrane and the second ultrafiltration membrane are selected according to the experimental needs and are peripherally fixed by copper wires, the copper wires are wrapped by sealing rings, and the ultrafiltration membranes in the upper and lower layers are fixed by the snap rings on the inner wall of the cavity at a specific height. Effective frequency of the first ultrasonic transmitting probe and the second ultrasonic transmitting probe is 15 kHz-40 kHz, and the power is 2000 w; the first ultrasonic transmitting probe and the second ultrasonic transmitting probe both comprise a plurality of probes arranged by being vertical to the barrel wall, and an interval among the adjacent probes is 5 cm.

Embodiment 7

(20) A method for preparing compound dispersoids of hydrophobic nanoparticles and surfactants with the abovementioned preparing apparatus as described in embodiments 1-6 comprises the following steps:

(21) (1) selecting the first ultrafiltration membrane 8 and the second ultrafiltration membrane 9 with suitable pore sizes according to the experimental requirements, mounting the second ultrafiltration membrane 9 onto the second snap ring 19, and then mounting the first ultrafiltration membrane 8 onto the first snap ring 18, wherein the pore size of the first ultrafiltration membrane 8 and the second ultrafiltration membrane 9 is 30-50 nm; then mounting a sealing ring 27 on the top lid of the ultrasonic dispersion instrument, and at last fixing the top lid 17 of the ultrasonic dispersion instrument with a bolt 26;
(2) tightly capping the top lid 17 of the ultrasonic dispersion instrument, delivering a required mass of surfactants to the first cavity 10 of the ultrasonic dispersion instrument 4 with a surfactant delivery pipeline, i.e. adding 20 g of di(2-ethyl hexyl) sodium sulphosuccinate (AOT); delivering a required mass of hydrophobic nanoparticles to the second cavity 11 of the ultrasonic dispersion instrument 4 with a hydrophobic nanoparticle delivery pipeline, i.e. adding 100 g of hydrophobic nanometer silica particles, wherein particle size of the hydrophobic nanometer silica particles is 20 nm; closing the surfactant delivery pipeline 15 and the hydrophobic nanoparticle delivery pipeline 16 after finishing the delivery;
(3) utilizing a first plunger pump 21 to inject water in a liquid storage tank into the ultrasonic dispersion instrument 4; controlling injection of water to be 10 L, i.e. controlling concentration of SiO.sub.2 in the compound dispersoids to be 1%, concentration of AOT to be 0.2%, and a concentration ratio of AOT to SiO.sub.2 to be 0.2;
(4) after injecting the water, circulating the hydrophobic nanoparticles, the surfactants and the water unidirectionally within the compounding mixing pipeline via a second plunger pump 6, and opening the first ultrasonic transmitting probe 13 and the second ultrasonic transmitting probe 14, wherein during the circular flow process of a water body within the ultrasonic dispersion instrument 4, water is firstly mixed with the surfactants in the upper space within the ultrasonic dispersion instrument 4 to form a dispersion solution of the surfactants and water under the action of ultrasonic cavitation of the first ultrasonic transmitting probe 13, then, the dispersion solution enters the second cavity 11 via the first ultrafiltration membrane 8, and the part of the dispersion solution that fails to meet the size requirement of the first ultrafiltration membrane 8 will be retained in the first cavity 10 and cannot enter the second cavity 11 until its particle size meets the size requirement of the first ultrafiltration membrane 8 through the action of ultrasonic cavitation by the first ultrasonic transmitting probe 13, a closed circulation loop is formed between the ultrasonic dispersion instrument and the liquid storage tank, and the first ultrasonic transmitting probe 13 and the second transmitting probe 14 are opened at the same time with an effective frequency set to be 20 kHz, the temperature control apparatus 25 is opened and the temperature is set to be 25 C. constantly;
(5) mixing the dispersion solution of the surfactants and water entering the second cavity 11 with the hydrophobic nanoparticles, wherein under ultrasonic cavitation of the second ultrasound transmitting probe 14, the hydrophobic nanoparticles are violently moved under provision of external energy to be dispersed, the surfactants are adsorbed on the surfaces of the hydrophobic nanoparticles to improve the dispersion stability in the dispersion process because of the fact that the hydrophobic nanoparticles have characteristics of high surface energy and adsorbability;
(6) enabling the compound dispersoids of the hydrophobic nanoparticles and the surfactants dispersed into appropriate sizes to enter the third cavity 12 via a second ultrafiltration membrane 9, and then circulating again to the ultrasonic dispersion instrument 4 via a liquid storage tank 5 and a second plunger pump 6;
(7) recirculating steps (1)-(6) to form compound dispersoids of the hydrophobic nanoparticles and the surfactants;
(8) circulating the compound dispersoids of the hydrophobic nanoparticles and the surfactants to the liquid storage tank 5;
(9) connecting the aggregating pipeline 3 with the liquid storage tank 5, and collecting the compound dispersoid to a compound dispersoid storage tank 23 by utilizing the third plunger pump 24, wherein after the process is circulated for set times, the compound dispersoids of the hydrophobic nanoparticles and the surfactants in the ultrasonic dispersion instrument 24 and the liquid storage tank 27 are pumped in a compound dispersion tank 34 via a plunger pump 32, such that the compound dispersoids of the hydrophobic nanoparticles and the surfactants are obtained.

Embodiment 8

(22) Embodiment 8 differs from the method for preparing the compound dispersoids of the hydrophobic nanoparticles and the surfactants in embodiment 7 in that a required mass of surfactants is delivered into the first cavity 10 of the dispersion instrument 4 via a surfactant delivery pipeline 15, 40 g of AOT is added, i.e. concentration of SiO.sub.2 in the compound dispersoids is controlled to be 1%, concentration of AOT is controlled to be 0.4% and a concentration ratio of AOT to SiO.sub.2 is 0.4.

Embodiment 9

(23) Embodiment 9 differs from the method for preparing the compound dispersoids of the hydrophobic nanoparticles and the surfactants in embodiment 7 in that a required mass of surfactant is delivered into the first cavity 10 of the dispersion instrument 4 via a surfactant delivery pipeline 15, 60 g of AOT is added, i.e. concentration of the SiO.sub.2 in the compound dispersoids is controlled to be 1%, concentration of AOT is controlled to be 0.6% and the concentration ratio of AOT to SiO.sub.2 is 0.6.

Embodiment 10

(24) Embodiment 10 differs from the method for preparing the compound dispersoids of the hydrophobic nanoparticles and the surfactants in embodiment 7 in that a required mass of surfactants is delivered into the first cavity 10 of the dispersion instrument 4 via a surfactant delivery pipeline 15, 60 g of SDS is added, i.e. concentration of the SiO.sub.2 in the compound dispersoids is controlled to be 1%, concentration of SDS is controlled to be 0.6% and a concentration ratio of SDS to SiO.sub.2 is 0.6.

(25) FIG. 4 is a comparative picture of the compound dispersoids obtained in embodiments 7-10, the compound dispersoid solution in a test tube No. 1 of FIG. 4 is prepared by conventional methods, i.e. concentration of SiO.sub.2 in the compound dispersoid is controlled to be 1%, concentration of AOT is controlled to be 0.4%, and then the final product is prepared by stirring with a magnetic stirrer at a speed of 1000 rpm for 30 min; test tubes No. 2, No. 3, No. 4 and No. 5 in FIG. 4 respectively correspond to the pictures of the compound dispersoids obtained in embodiments 7-10.

(26) FIG. 5 is a TEM photomicrograph of the compound dispersoids prepared by the conventional methods; FIG. 6-FIG. 9 are TEM photomicrographs of the compound dispersoids obtained in embodiments 7-10. It can be seen from comparison that agglomeration clearly takes place in the nanoparticles in the compound dispersoids prepared with the conventional methods, larger cluster structures are formed, while the compound dispersoids prepared with the apparatus and method of the present invention show a very good dispersion state which is the best in picture No. 3 (i.e. when the concentration ratio of AOT to SiO.sub.2 in embodiment 8 is 0.4).