Carbon cloth material coated with iodine-doped bismuthyl carbonate, preparation method thereof, and application in oil-water separation

Abstract

The present invention discloses a carbon cloth material coated with iodine-doped bismuthyl carbonate, a preparation method thereof, and application in oil-water separation. The preparation method comprises the following steps: immersing preprocessed carbon cloth in iodine-doped bismuthyl carbonate precursor solution, and carrying out hydrothermal reaction to obtain the carbon cloth material coated with iodine-doped bismuthyl carbonate, wherein the iodine-doped bismuthyl carbonate precursor solution comprises bismuth citrate, sodium carbonate, sodium iodide and ethylene glycol. Through a hydrothermal method, the carbon cloth coated with iodine-doped bismuthyl carbonate is synthesized in one step, and the carbon cloth material has a function of emulsion separation. The material has the advantages of simple preparation, abundant raw material, good separation effect and good application prospect on the aspects of industrial sewage treatment and emulsion separation.

Claims

1. A method for separating oil and water, comprising the following steps: (1) immersing a pretreated carbon cloth in an iodine-doped bismuthyl carbonate precursor solution, and carrying out hydrothermal reaction to obtain the carbon cloth material coated with iodine-doped bismuthyl carbonate; the iodine-doped bismuthyl carbonate precursor solution includes bismuth citrate, sodium carbonate, sodium iodide, and ethylene glycol; (2) introducing the oil-water emulsion to be separated into the carbon cloth material coated with iodine-doped bismuthyl carbonate to complete the separation of oil and water.

2. The method according to claim 1, wherein dissolving sodium carbonate powder in water at room temperature, and adding ethylene glycol, and after stirring, adding bismuth citrate powder, and stirring the mixture until the solution is colorless and transparent, and then adding sodium iodine powder to obtain the iodine-doped bismuthyl carbonate precursor solution.

3. The method according to claim 1, wherein said hydrothermal reaction is carried out at 180° C. for 24 h.

4. The method according to claim 1, wherein the carbon cloth is ultrasonically washed with acetone, ethanol and deionized water respectively, and then immersed in concentrated nitric acid to obtain the pretreated carbon cloth.

5. The method according to claim 1, wherein said hydrothermal reaction is carried out twice, and the conditions of the two hydrothermal reactions are the same.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a scanning electron micrograph of carbon cloth before and after modification;

(2) FIG. 2 is a wettability test of the modified carbon cloth;

(3) FIG. 3 is a separation test of the oil/water emulsion of the modified carbon cloth;

(4) FIG. 4 is a cyclic efficiency test of the modified carbon cloth;

(5) FIG. 5 is a cyclic flux test of the modified carbon cloth.

DETAILED DESCRIPTION OF THE INVENTION

Embodiment 1

(6) The preparation of the iodine-doped bismuthyl carbonate precursor solution is as follows:

(7) Dissolve 1.325 g of sodium carbonate powder in 100 ml of water at room temperature, add 25 ml of ethylene glycol, and stir for 20 minutes; add 5 g of bismuth citrate to the above solution, continuously stirring until the solution is colorless and transparent. Finally, add 3.5 g of sodium iodide, stir for 20 minutes to obtain an iodine-doped bismuthyl carbonate precursor solution.

(8) The carbon cloth is ultrasonically washed with acetone, ethanol and deionized water, and then immersed in concentrated nitric acid for 6 hours to obtain a pretreated carbon cloth. The SEM image is shown in FIG. 1.

(9) The specific steps of the hydrothermal method are as follows:

(10) The pretreated carbon cloth is immersed in an iodine-doped bismuthyl carbonate precursor solution, and then the solution and carbon cloth are transferred to a 150 ml stainless steel autoclave, and reacted at 180° C. for 24 hours. After the reaction, the carbon cloth is washed twice with ethanol and deionized water, and then the carbon cloth is placed in the autoclave for a second reaction, and reacted at 180° C. for 24 hours. After the reaction, the carbon cloth is washed twice with ethanol and deionized water to obtain a carbon cloth material coated with iodine-doped bismuthyl carbonate. The SEM image is shown in FIG. 1.

(11) FIG. 1 is a SEM image of a carbon cloth before and after modification. (a) is a SEM image of carbon cloth before modification, (b), (c), and (d) are SEM images of products at different resolutions. It can be seen from the figure that a large amount of iodine-doped bismuthyl carbonate nanosheet uniformly grows on the surface.

Embodiment 2

(12) Wettability test of carbon cloth coated with iodine-doped bismuthyl carbonate

(13) FIG. 2 is a wettability test. The carbon cloth coated with iodine-doped bismuthyl carbonate exhibits superhydrophilicity in the air. When the water droplets and the oil droplets contact the surface of the carbon cloth, they spread rapidly and the contact angle is 0°. When the carbon cloth is immersed in water, chloroform aggregates into a spherical shape on the surface of the carbon cloth, and the contact angle is 154°; when the carbon is placed in toluene, the water droplets also aggregates into a spherical shape on the surface, and the contact angle is 153°. The results show that the modified carbon cloth meets the wettability requirements for oil/water emulsion separation. (a) is the contact angle of water in air, (b) is the contact angle of toluene in air, and (c) is the contact angle of toluene under water, and (d) is the contact angle of chloroform under water.

Embodiment 3

(14) The emulsion separation test, the specific steps are as follows:

(15) 10 ml of toluene is added to 90 ml of water, and then 50 mg of sodium dodecyl sulfate is added and stirred for 2 hours, after which the prepared emulsion is used for the emulsion separation test.

(16) A carbon cloth coated with iodine-doped bismuthyl carbonate is placed in a glass filter, and then 100 ml oil/water emulsion is poured in. FIG. 3 is a step of separating the oil/water emulsion. As can be seen from the figure, after pouring the milky white oil/water emulsion into the glass filter, the purified water flows into the glass filter flask, indicating that it has good emulsion separation effectiveness.

Embodiment 4

(17) Separation efficiency and flux test, the specific steps are as follows:

(18) Separation efficiency and flux. The separation efficiency of the oil/water emulsion is calculated using the following equation:
R (%)=(1−Cp/Co)×100%

(19) Where R (%) is the oil displacement coefficient, and Cp and Co are the oil concentrations of the collected water and oil/water emulsion, respectively. Purified water is analyzed by UV-visible spectrophotometry. The flux of the emulsion is determined by calculating the amount of filtration per unit time according to the following equation:
Flux=V/At

(20) Where A (cm.sup.2) is the effective filtration surface of the membrane, V (L/m.sup.2h) is the volume of the filtrate, and t (h) is the separation time. Pour the same amount of oil/water emulsion in each test.

(21) FIGS. 4 and 5 show the cyclic separation effect and flux of the material on the toluene-in water and hexane-in-water emulsions. It can be found that the material still maintains a good separation effect after the cycle test.

(22) Through the above analysis, a carbon cloth material coated with iodine-doped bismuthyl carbonate is synthesized by a hydrothermal method in one step in the invention, and has the function of separating the emulsion. The material has the advantages of simple preparation, easy availability of raw materials, good separation effect and good cycle ability, and has good application prospects in industrial sewage treatment and emulsion separation.