UIO-66-NH.SUB.2.doped organosilicon high salinity wastewater treatment membrane and a preparation method thereof

Abstract

The invention belongs to the technical field of composite membrane, and in particular discloses a UIO-66-NH.sub.2 doped organosilicon high salinity wastewater treatment membrane and a preparation method thereof. The membrane is formed into UIO-66-NH.sub.2/organosilicon hybrid membrane on the prefabricated ceramic support surface through the dip-coating method by doping the UIO-66-NH.sub.2 metal-organic framework material into the organosilicon polymeric sol. The UIO-66-NH.sub.2/organosilicon hybrid membrane prepared by the present invention exhibits high water permeability (up to 1.6×10.sup.−10 m.sup.3/(m.sup.2 s Pa) and high salt retention (NaCl retention rate is more than 99.9. %) in the application of pervaporation desalination, and maintains stable membrane structure in the treatment process of TDS>5 wt % high salinity wastewater.

Claims

1. A method of preparing a UiO-66-NH.sub.2 doped organosilicon high salinity wastewater treatment membrane, the method comprising steps of: (1) hydrolyzing and polymerizing a silicon source precursor and a hydrochloric acid catalyst with water in ethanol solution to obtain an organosilicon polymeric sol; (2) adding UiO-66-NH.sub.2 crystal into the organosilicon polymeric sol by ultrasonic mixing and uniform dispersion to prepare a UiO-66-NH.sub.2/organosilicon hybrid sol; (3) dip-coating the UiO-66-NH.sub.2/organosilicon hybrid sol on a ceramic support of a silica-zirconia nanometer transition layer; and (4) flash-burning the dip-coated UiO-66-NH.sub.2/organosilicon hybrid sol in air to obtain the UiO-66-NH.sub.2 doped organosilicon high salinity wastewater treatment membrane.

2. The method of claim 1, wherein the silicon source precursor according to the step (1) is 1,2-Bis(triethoxysilyl)ethylene, abbreviated as BTESEthy.

3. The method of claim 1, wherein the silicon source precursor, the water and the hydrochloric acid catalyst according to the step (1) are having a molar ratio of 1:60:0.2; wherein a hydrolytic-polymeric reaction temperature according to the step (1) is 40 DEG C; and wherein a hydrolytic-polymeric reaction time according to the step (1) is 2 h.

4. The method of claim 1, wherein the step (2) comprises is: dissolving ZrCl.sub.4 and 2-amino-1,4-benzenedicarboxylic acid in N,N-dimethylformamide (DMF) resulting in a first mixture and subjecting the first mixture to ultrasonic agitation for 10 min; adding acetic acid to the first mixture resulting in a second mixture and subjecting the second mixture to ultrasonic agitation for 10 min; putting the second mixture into a preheated 130 DEG C oven for 24 h resulting in a product UiO-66-NH.sub.2; washing the product UiO-66-NH.sub.2 with N,N-dimethylformamide and methanol; and drying the washed product UiO-66-NH.sub.2 overnight at 100 DEG C to obtain the UiO-66-NH.sub.2 crystal; wherein molar ratio of ZrCl.sub.4, BDC-NH.sub.2, HAC and DMF is 1:1:50:500.

5. The method of claim 1, wherein weight ratio (UB-n) of UiO-66-NH.sub.2 and organosilicon in the hybrid sol according to the step (2) is 0.2-1.

6. The method of claim 1, wherein the ultrasonic mixing duration according to the step (2) is 30 min.

7. The method of claim 1, wherein the ceramic support according to the step (3) is a α-Al.sub.2O.sub.3 ceramic membrane.

8. The method of claim 1, wherein the step (3) comprises: soaking the ceramic support of the silica-zirconia nanometer transition layer in a silica-zirconia sol for 10-60 s; drying the soaked ceramic support at room temperature for 5-10 min; and calcining the dried ceramic support in air for 15-30 min at a temperature of 500-600 DEG C under air atmosphere; and repeating the calcination 2-3 times.

9. The method of claim 1, wherein the flash-burning temperature according to the step (3) is 250 DEG C; and the flash-burning time according to the step (3) is 20 min.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 depicts the water flux and the salt retention rate of BTESEthy membrane and UiO-66-NH.sub.2BTESEthy composite membrane in 6.5 wt % NaCl solution at 70° C.

(2) FIG. 2 depicts the isothermal curves of nitrogen adsorption for BTESEthy, UiO-66-NH.sub.2/BTESEthy and UB-0.5 membranes.

(3) FIG. 3A depicts the SEM images of top view for UB-0.5 membrane; and FIG. 3B depicts the SEM images of cross-section view for UB-0.5 membrane.

(4) FIG. 4 depicts the desalination hydrothermal stability test of UB-0.5 membrane.

DETAILED DESCRIPTION

(5) The present invention further illustrates the technical features of the present invention by combining the following embodiments, but the protection scope of the present invention is not limited to the embodiments.

Embodiment 1

(6) The preparation method for the embodiment is as follows, including the following steps:

(7) (1) 1,2-Bis(triethoxysilyl) ethylene (BTESEthy) (as silicon source precursor) and hydrochloric acid (as catalyst) are hydrolyzed and polymerized with water in ethanol solution. The molar ratio of BTESEthy, water and hydrochloric acid is 1:60:0.2, and the solution is subjected to agitation at 40° C. for 2 h to obtain the BTESEthy polymeric sol.

(8) (2) ZrCl.sub.4 and 2-amino-1,4-benzenedicarboxylic acid are dissolved in N,N-dimethylformamide and subjected to ultrasonic agitation for 10 min, then the acetic acid is added and subjected to ultrasonic agitation for 10 min (the molar ratio of ZrCl.sub.4, BDC-NH.sub.2, HAC and DMF is 1:1:50:500). The mixture is put into the preheated 130 DEG C oven for 24 h. Finally, the product UiO-66-NH.sub.2 is washed with N,N-dimethylformamide and methanol, and dried overnight at 100 DEG C to obtain the UiO-66-NH.sub.2 crystal.

(9) (3) The UiO-66-NH.sub.2 crystal is added into the BTESEthy polymeric sol and subjected to ultrasonic mixing and uniform dispersion for 30 min to prepare the UiO-66-NH.sub.2/BTESEthy hybrid sol. The UiO-66-NH.sub.2/BTESEthy sample of different composition is designated as UB-n (n=0.2, 0.5, 0.8 or 1) to indicate the weight ratio of UiO-66-NH.sub.2 and BTESEthy in solution.

(10) (4) The UiO-66-NH.sub.2/BTESEthy hybrid sol is coated on the α-Al.sub.2O.sub.3 ceramic support comprising the silica-zirconia nanometer transition layer through the dip-coating method, wherein the ceramic support comprising the silica-zirconia transition layer is soaked in the silica-zirconia sol for 40 s, and then dried at room temperature for 7 min and calcined for 20 min. The calcination temperature is 500 DEG C, and the calcination atmosphere is air. The process is repeated 2-3 times. After coating, the flash burning is carried out in air at 250 DEG C for 20 min to obtain the UiO-66-NH.sub.2/BTESEthy hybrid membrane. The membrane prepared is applied to the pervaporation desalination system.

Embodiment 2

(11) The preparation method for the embodiment is as follows, including the following steps:

(12) (1) 1,2-Bis(triethoxysilyl)ethylene (BTESEthy) (as silicon source precursor) and hydrochloric acid (as catalyst) are hydrolyzed and polymerized with water in ethanol solution. The molar ratio of BTESEthy, water and hydrochloric acid is 1:60:0.2, and the solution is subjected to agitation at 40° C. for 2 h to obtain the BTESEthy polymeric sol.

(13) (2) ZrCl.sub.4 and 2-amino-1,4-benzenedicarboxylic acid are dissolved in N,N-dimethylformamide and subjected to ultrasonic agitation for 10 min, then the acetic acid is added and subjected to ultrasonic agitation for 10 min (the molar ratio of ZrCl.sub.4, BDC-NH.sub.2, HAC and DMF is 1:1:50:500). The mixture is put into the preheated 130 DEG C oven for 24 h. Finally, the product UiO-66-NH.sub.2 is washed with N,N-dimethylformamide and methanol, and dried overnight at 100 DEG C to obtain the UiO-66-NH.sub.2 crystal.

(14) (3) The UiO-66-NH.sub.2 crystal is added into the BTESEthy polymeric sol and subjected to ultrasonic mixing and uniform dispersion for 30 min to prepare the UiO-66-NH.sub.2/BTESEthy hybrid sol. The UiO-66-NH.sub.2/BTESEthy sample of different composition is designated as UB-n (n=0.2, 0.5, 0.8 or 1) to indicate the weight ratio of UiO-66-NH.sub.2 and BTESEthy in solution.

(15) (4) The UiO-66-NH.sub.2/BTESEthy hybrid sol is coated on the α-Al.sub.2O.sub.3 ceramic support comprising the silica-zirconia nanometer transition layer through the dip-coating method, wherein the ceramic support comprising the transition layer is soaked in the silica-zirconia sol for 40 s, and then dried at room temperature for 7 min and calcined for 20 min. The calcination temperature is 500 DEG C, and the calcination atmosphere is air. The process is repeated 2-3 times. After coating, the flash burning is carried out in air at 250 DEG C for 20 min to obtain the UiO-66-NH.sub.2/BTESEthy hybrid membrane. The membrane prepared is applied to the pervaporation desalination system.

(16) Comparative 1

(17) (1) 1,2-Bis(triethoxysilyl)ethane (BTESEthy) (as silicon source precursor) and hydrochloric acid (as catalyst) are hydrolyzed and polymerized with water in ethanol solution. The molar ratio of BTESEthy, water and hydrochloric acid is 1:60:0.2, and the solution is subjected to agitation at 40° C. for 2 h to obtain the BTESEthy polymeric sol.

(18) (2) The BTESEthy sol is coated on the α-Al.sub.2O.sub.3 ceramic support comprising the silica-zirconia nanometer transition layer through the dip-coating method, wherein the ceramic support comprising the transition layer is soaked in the silica-zirconia sol for 40 s, and then dried at room temperature for 7 min and calcined for 20 min. The calcination temperature is 500 DEG C, and the calcination atmosphere is air. The process is repeated 2-3 times. After coating, the flash burning is carried out in air at 250 DEG C for 20 min to obtain the BTESEthy membrane. The membrane prepared is applied to the pervaporation desalination system.

(19) Comparative 2

(20) (1) 1,2-Bis(triethoxysilyl)ethane (BTESEthy) (as silicon source precursor) and hydrochloric acid (as catalyst) are hydrolyzed and polymerized with water in ethanol solution. The molar ratio of BTESEthy, water and hydrochloric acid is 1:60:0.2, and the solution is subjected to agitation at 40° C. for 2 h to obtain the BTESEthy polymeric sol.

(21) (2) The 0.160 ZrCl.sub.4 and the 0.124 g 2-amino-1,4-benzenedicarboxylic acid are dissolved in 10 mL N,N-dimethylformamide and subjected to ultrasonic agitation for 10 min, then 2 mL acetic acid is added and subjected to ultrasonic agitation for 10 min (the molar ratio of ZrCl.sub.4, H.sub.2BDC, HAC and DMF is 1:1:50:500). The mixture is put into the preheated 130 DEG C oven for 24 h. Finally, the product UiO-66 is washed with N,N-dimethylformamide and methanol, and dried overnight at 100 DEG C to obtain the UiO-66 crystal.

(22) (3) The UiO-66 crystal is added into the BTESEthy polymeric sol and subjected to ultrasonic mixing and uniform dispersion for 30 min to prepare the UiO-66/BTESEthy hybrid sol. The weight ratio of UiO-66 and BTESEthy is 0.5.

(23) (4) The UiO-66/BTESEthy hybrid sol is coated on the α-Al.sub.2O.sub.3 ceramic support comprising the silica-zirconia nanometer transition layer through the dip-coating method, wherein the ceramic support comprising the transition layer is soaked in the silica-zirconia sol for 40 s, and then dried at room temperature for 7 min and calcined for 20 min. The calcination temperature is 500 DEG C, and the calcination atmosphere is air. The process is repeated 2-3 times. After coating, the flash burning is carried out in air at 250 DEG C for 20 min to obtain the UiO-66/BTESEthy hybrid membrane. The membrane prepared is applied to the pervaporation desalination system.

(24) The experimental results of above embodiments and comparatives are shown in Table 1.

(25) TABLE-US-00001 TABLE 1 Flux Retention rate Membrane 10.sup.−11 m.sup.3/(m.sup.2 s Pa) (%) Embodiment 1 7.4 99.98 Embodiment 2 7.3 99.98 Comparative 1 5.7 99.97 Comparative 2 6.1 99.98