HYDROGEL CAPABLE OF BEING USED FOR SEAWATER DESALINATION AND PREPARATION METHOD THEREFOR

Abstract

A hydrogel capable of desalinating seawater and a preparation method thereof. The hydrogel is a polymer polymerized by a monomer containing a hydrophilic group and a carbon-carbon double bond via carbon-carbon double bonds. A degree of crosslinking of the polymer is 0.01 to 0.2. The monomer accounts for 5 wt % to 50 wt % of a mass of the hydrogel. The preparation method includes: mixing a monomer with a pore-forming agent, a cross-linking agent, a initiator and a catalyst evenly, obtaining a mixed material, then transferring the mixed material into a die; conducting a polymerization for 2 to 3 hours at a temperature of 20 C. to 30 C. first, followed by increasing the temperature to continue the polymerization until the polymerization is completed; and obtaining the hydrogel capable of desalinating seawater. The method according is convenient and efficient, and has advantages of being used under special conditions such as earthquake relief work, maritime rescue and wild adventure.

Claims

1-9. (canceled)

10. A hydrogel capable of desalinating seawater, comprising: a hydrogel that is a polymer polymerized by a monomer containing a hydrophilic group and a carbon-carbon double bond via carbon-carbon double bonds; a degree of crosslinking of the polymer is 0.01 to 0.2; and the monomer accounts for 5 wt % to 50 wt % of a mass of the hydrogel.

11. The hydrogel capable of desalinating seawater according to claim 10, wherein the monomer is one or more of compounds of methacrylic acid, acrylic acid, sodium acrylate, methacrylates and acrylates.

12. The hydrogel capable of desalinating seawater according to claim 11, wherein the methacrylates include one or more of hydroxyethyl methylacrylate (HEMA), (2-hydroxyethoxy)ethyl methacrylate, methoxyethyl methacrylate, (2-methoxyethoxy)ethyl methacrylate, ethylene dimethacrylate (EDMA), and 2-ethoxyethyl methacrylate (EEMA).

13. The hydrogel capable of desalinating seawater according to claim 11, wherein the acrylates include one or more of methyl acrylate, ethyl acrylate, butyl acrylate, hydroxyethyl acrylate, and methoxyethyl acrylate.

14. The hydrogel capable of desalinating seawater according to claim 10, wherein the hydrogel is a homopolymer polymerized by a monomer, or a copolymer polymerized by two or more of monomers; and a pore size of the hydrogel is 0.1 m to 20 m.

15. A method of preparing the hydrogel capable of desalinating seawater according to claim 10, comprising: mixing a monomer with a pore-forming agent, a cross-linking agent, an initiator and a catalyst evenly, obtaining a mixed material, then transferring the mixed material into a die; conducting a polymerization for 2 to 3 hours at a temperature of 20 C. to 30 C. first, followed by increasing the temperature to continue the polymerization until the polymerization is completed; and obtaining the hydrogel capable of desalinating seawater.

16. The method according to claim 15, wherein the cross-linking agent is one or more of ethylene dimethacrylate (EDMA), N,N-methylenebisacrylamide (MBA) and 1,5-hexadiene-3,4-diol (DVG), and a ratio of amount of substance of the cross-linking agent to the monomer is 0.01 to 0.2.

17. The method according to claim 15, wherein the initiator is one or more of ammonium persulphate (APS), azodiisobutyronitrile (AIBN) and benzoyl peroxide (BPO), an amount of the initiator being a concentration in the mixed material of 1.0 mmol/L to 3.0 mmol/L; the catalyst is N,N,N,N-tetramethylethylenediamine (TEMED), an amount of the catalyst accounting for 0.2% (V/V) to 0.5% (V/V) of a total volume of the mixed material; and the pore-forming agent is deionized water, an amount of the pore-forming agent a 50 wt % to 95 wt % of a total weight of the hydrogel.

18. The method according to claim 15, wherein when increasing the temperature to continue the polymerization, a polymerization temperature is 40 C. to 120 C., and a polymerization time is 1 hour to 48 hours.

Description

DETAILED DESCRIPTION OF THE PREFERED EMBODIMENT

[0026] The present invention will be further specifically described in detail below in combination with embodiments, but implementations of the present invention are not limited thereto. For process parameters that are not specifically noted, may refer to conventional techniques.

[0027] Seawater in the present invention is replaced by an aqueous solution of sodium chloride which is a main ingredient in the seawater at a concentration of 35.00 g/L, but is not limited thereto. The selected hydrogel is poly(hydroxyethyl methacrylate), poly(hydroxyethyl methylacrylate-sodium acrylate), sodium polyacrylate and poly(hydroxyethyl methylacrylate-methacrylic acid). Mass fraction of hydroxyethyl methylacrylate in the poly(hydroxyethyl methylacrylate) is 10 wt %, 15 wt %, 20 wt %, respectively; Mass fraction of hydroxyethyl methylacrylate in the poly(hydroxyethyl methylacrylate-sodium acrylate) is 15 wt % and 10 wt %, respectively, and mass fraction of the sodium acrylate is 5 wt % and 10 wt %, respectively. That is, after polymerization, the monomer accounts for 20 wt % of a total mass of the hydrogel. The hydrogel described in the present invention is not limited thereto.

Embodiment 1

[0028] Poly(hydroxyethyl methylacrylate-sodium acrylate) containing 15 wt % of hydroxyethyl methylacrylate (HEMA) and 5 wt % of sodium acrylate (SA) (HEMA15/SA5) was prepared. 7.5 g of HEMA, 2.5 g of SA and 40 g of water were weighted and put into a conical flask for evenly stirring, and then 150 l of ethylene dimethacrylate (EDMA), 200 l of 10% of ammonium persulphate (APS) solution and 100 l of N,N,N,N-tetramethylethylenediamine (TEMED) were added in order and evenly mixed. The evenly mixed solution was transferred to a mold, and the mold was put into a thermostat. Isothermal polymerization was carried out at 30 C. for 3 hours and then at 75 C. for 24 hours. The polymerized hydrogel was then washed thoroughly with deionized water and then freeze-dried at 45 C. in a freeze dryer for 24 hours. The hydrogel according to the present invention was obtained. The hydrogel was put into the seawater for swelling and then squeezed. By testing, the concentration of sodium chloride in the squeezed liquid was 12.40 g/L, and the desalination rate was 64.57%.

Embodiment 2

[0029] Poly(hydroxyethyl methylacrylate-sodium acrylate) containing 10 wt % of hydroxyethyl methylacrylate and 10 wt % of sodium acrylate (HEMA10/SA10) was prepared. 5 g of HEMA, 5 g of SA and 40 g of water were weighted and put into a conical flask for evenly stifling, and then 175 l of EDMA, 200 l of 10% APS solution and 100 l of TEMED were added in order and evenly mixed. The evenly mixed solution was transferred to a mold, and the mold was put into a thermostat. Isothermal polymerization was carried out at 30 C. for 3 hours and then at 75 C. for 24 hours. The polymerized hydrogel was then washed thoroughly with deionized water and then freeze-dried at 45 C. in a freeze dryer for 24 hours. The hydrogel according to the present invention was obtained. The hydrogel was put into the seawater for swelling and then was squeezed. By testing, the concentration of sodium chloride in the squeezed liquid was 15.28 g/L, and the desalination rate was 56.34%.

Embodiment 3

[0030] Poly(hydroxyethyl methylacrylate) containing 20 wt % of hydroxyethyl methylacrylate (HEMA20) was prepared. 10 g of HEMA and 40 g of water were weighted and put into a conical flask for evenly stirring, and then 50 l of EDMA, 400 l of 10% APS solution and 100 l of TEMED were added in order and evenly mixed. The evenly mixed solution was transferred to a mold, and the mold was put into a thermostat. Isothermal polymerization was carried out at 25 C. for 3 hours and then at 80 C. for 24 hours. The polymerized hydrogel was then washed thoroughly with deionized water and then freeze-dried at 45 C. in a freeze dryer for 24 hours. The hydrogel according to the present invention was obtained. The hydrogel was put into the seawater for swelling and then was squeezed. By testing, the concentration of sodium chloride in the squeezed liquid was 25.33 g/L, and the desalination rate was 27.63%.

Embodiment 4

[0031] Poly(hydroxyethyl methylacrylate) containing 15 wt % of hydroxyethyl methylacrylate (HEMA15) was prepared. 7.5 g of HEMA and 42.5 g of water were weighted and put into a conical flask for evenly stirring, and then 37.5 l of EDMA, 300 l of 10% APS solution and 75 l of TEMED were added in order and evenly mixed. The evenly mixed solution was transferred to a mold, and the mold was put into a thermostat. Isothermal polymerization was carried out at 25 C. for 3 hours and then at 80 C. for 24 hours. The polymerized hydrogel was then washed thoroughly with deionized water and then freeze-dried at 45 C. in a freeze dryer for 24 hours. The hydrogel according to the present invention was obtained. The hydrogel was put into the seawater for swelling and then was squeezed. By testing, the concentration of sodium chloride in the squeezed liquid was 26.50 g/L, and the desalination rate was 32.08%.

Embodiment 5

[0032] Poly(hydroxyethyl methylacrylate) containing 10 wt % of hydroxyethyl methylacrylate (HEMA10) was prepared. 5 g of HEMA and 45 g of water were weighted and put into a conical flask for evenly stirring, and then 25 l of EDMA, 200 l of 10% APS solution and 50 l of TEMED were added in order and evenly mixed. The evenly mixed solution was transferred to a mold, and the mold was put into a thermostat. Polymerization was carried out at 25 C. for 3 hours and then at 80 C. for 24 hours. The polymerized hydrogel was then washed thoroughly with deionized water and then freeze-dried at 45 C. in a freeze dryer for 24 hours. The hydrogel according to the present invention was obtained. The hydrogel was put into the seawater for swelling and then was squeezed. By testing, the concentration of sodium chloride in the squeezed liquid was 27.50 g/L, and the desalination rate was 21.42%.

Embodiment 6

[0033] Sodium polyacrylate containing 10 wt % of sodium acrylate (SA10) was prepared. 5 g of SA and 45 g of water were weighted and put into a conical flask for evenly stirring, and then 25 l of N-Nmethylene bisacrylamide (MBA), 200 l of 10% APS solution and 50 l of TEMED were added in order and evenly mixed. The evenly mixed solution was transferred to a mold, and the mold was put into a thermostat. Isothermal polymerization was carried out at 25 C. for 3 hours and then at 70 C. for 24 hours. The polymerized hydrogel was then washed thoroughly with deionized water and then freeze-dried at 45 C. in a freeze dryer for 24 hours. The hydrogel according to the present invention was obtained. The hydrogel was put into the seawater for swelling and then was squeezed. By testing, the concentration of sodium chloride in the squeezed liquid was 28.13 g/L, and the desalination rate was 19.51%.

Embodiment 7

[0034] Poly(hydroxyethyl methylacrylate-methacrylic acid) containing and copolymerized by 19.9 wt % of hydroxyethyl methylacrylate and 0.2 wt % of methacrylic acid (MA) was prepared. 10 g of HEMA, 0.1 g of MA and 40 g of water were weighted and put into a conical flask for evenly stirring, and then 50 l of EDMA, 400 l of 10% APS solution and 100 l of TEMED were added in order and evenly mixed. The evenly mixed solution was transferred to a mold, and the mold was put into a thermostat. Isothermal polymerization was carried out at 25 C. for 3 hours and then at 80 C. for 24 hours. The polymerized hydrogel was then washed thoroughly with deionized water and then freeze-dried at 45 C. in a freeze dryer for 24 hours. The hydrogel according to the present invention was obtained. The hydrogel was put into the seawater for swelling and then was squeezed. By testing, the concentration of sodium chloride in the squeezed liquid was 27.69 g/L, and the desalination rate was 20.89%.

[0035] The formula of preparing the hydrogel will have a significant effect on the structure of the hydrogel. When the mass fraction of the monomer of the hydrogel is less than 5 wt %, the hydrogel is formed relatively soft and cannot be squeezed, meanwhile the high moisture content leads to the hydrogel exhibiting a large pore structure of 20 m or more, and the salt ions in seawater cannot be adsorbed and screened; whereas when the mass fraction of the monomer of the hydrogel is more than 50 wt %, a degree of swelling of the whole hydrogel is low, a single treating amount of seawater is small and swelling behavior is not obvious in seawater, a treating time is prolonged while a recovery rate is greatly reduced, and thus there is no practical value. When the degree of crosslinking of the hydrogel is less than 0.01 (molar ratio), the hydrogel exhibits a viscous fluid that does not have dilution properties; whereas when the degree of crosslinking is more than 0.2 (molar ratio), the hydrogel is over cross-linked, resulting in slow swelling in saline while the hydrogel colloid is relatively hard and less favorable for squeezing.

[0036] The above-described embodiments of the present invention are just examples for describing the present invention clearly, but not limitation to the implementations of the present invention. For those having ordinary skill in the art, variations or changes in different forms can be made on the basis of the above description. All of the implementations should not and could not be exhaustive herein. Any amendment, equivalent replacement and improvement made within the spirit and principle of the present invention shall all be included within the scope of protection of the claims of the present invention.