WO2016018870A1

WO2016018870A1 - Method and composition for water treatment and methods for preparing the composition

Info

Publication number: WO2016018870A1
Application number: PCT/US2015/042387
Authority: WO
Inventors: Zhida Pan; Yanju Wang; Wenqing Peng; Jason Louis DAVIS; Qiongqiong HUANG; Lin Wang
Original assignee: General Electric Company
Priority date: 2014-07-28
Filing date: 2015-07-28
Publication date: 2016-02-04
Also published as: CN105293618A

Abstract

A method for water treatment, includes: contacting water with an effective amount of a composition comprising a polymer derived from a first monomer of formula I: (formula I), and a second monomer selected from : (formula), and (formula), to obtain a treated water with reduced chemical oxygen demand; and separating the treated water from the composition; wherein, a weight percentage of the first monomer to a total of the first and the second monomers is in a range of from 0 to 90%; R¹, independently at each occurrence, is, H, C₁-C₁₈ alkyl, alkoxyl, or phenyl; R² is C₁-C₁₈ alkyl, alkoxyl, or phenyl; and a is an integer ranging from 0-4. An associated composition and a method for preparing the same are also described.

Description

METHOD AND COMPOSITION FOR WATER TREATMENT AND METHOD FOR

PREPARING THE COMPOSITION

BACKGROUND

[0001] The invention relates generally to methods and compositions for water treatment and methods for making the compositions.

[0002] Compositions comprising polymers are used in water treatments for the removal and/or recovery of materials from water. Some compositions are expensive because of the high cost of the monomer, such as glycidyl methacrylate and hydroxy ethyl methacrylate. Some compositions are unsatisfactory due to the low removal/recovery rate, the complicated preparation process, and/or the poor capability of being regenerated for reuse/recycle.

[0003] In addition, significant costs are often associated with the need to transport compositions off site for high temperature or other specialized regeneration conditions.

Compositions which can be regenerated on site with simple processes such as low temperature chemical or steam stripping can significantly reduce the costs associated with the treatment, as well as, the recovery of the materials being adsorbed by the compositions.

[0004] Therefore, it is desirable to provide new methods and compositions for water treatment and methods for making the compositions.

BRIEF DESCRIPTION

[0005] In one aspect, the invention relates to a method for water treatment, comprising: contacting water with an effective amount of a composition comprising a polymer derived from a first monomer of formula I:

and a second monomer selected from:

to obtain a treated water with reduced chemical oxygen demand; and separating the treated water from the composition; wherein a weight percentage of the first monomer to a total of the first and the second monomers is in a range of from 0 to 90%; R¹, independently at each occurrence, is, H, Ci-Cis alkyl, alkoxyl, or phenyl; R² is Ci-Ci₈ alkyl, alkoxyl, or phenyl; and a is an integer ranging from 0-4.

[0006] In another aspect, the invention relates to a composition comprising a polymer derived from a first monomer of formula I:

and a second monomer selected from:

wherein a weight percentage of the first monomer to a total of the first and the second monomers is in a range of from greater than 0 to 90%; R¹, independently at each occurrence, is, H, Ci-Cig alkyl, alkoxy, or phenyl; R² is Ci-Cis alkyl, alkoxy, or phenyl; and a is an integer ranging from 0-4.

[0007] In yet another aspect, the invention relates to a method, comprising: preparing an aqueous phase comprising water, a stabilizer and optionally a surfactant; preparing an organic phase comprising an initiator, an organic solvent, a first monomer of formula I:

and a second monomer selected from:

mixing the aqueous phase with the organic phase for polymerization to obtain a composition in a form of beads; wherein a weight percentage of the first monomer to a total of the first and the second monomers is in a range of from 0 to 90%; R¹, independently at each occurrence, is, H, C1-C18 alkyl, alkoxy, or phenyl; R² is Ci-Cig alkyl, alkoxy, or phenyl; and a is an integer ranging from 0-4.

DRAWINGS

[0008] These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings, wherein:

[0009] FIG. 1 illustrates the thermogravimetric analysis (TGA) of the adsorbent beads prepared in experiment run 31. DETAILED DESCRIPTION

[0010] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this disclosure belongs. The use of "including", "comprising" or "having" and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0011] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about" is not to be limited to the precise value specified. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.

[0012] In the specification and the claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Moreover, the suffix "(s)" as used herein is usually intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term. The terms "first," "second," and the like, herein do not denote any order, quantity, or importance, but rather are used to, such as, distinguish one element from another or one embodiment from another.

[0013] As used herein, the term "or" is not meant to be exclusive and refers to at least one of the referenced components (for example, a material) being present and includes instances in which a combination of the referenced components may be present, unless the context clearly dictates otherwise.

[0014] Reference throughout the specification to "some embodiments", and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the invention is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described inventive features may be combined in any suitable manner in the various embodiments. [0015] Embodiments of the present invention relate to methods and compositions for water treatments and methods for preparing the compositions.

[0016] The chemical oxygen demand (COD) and total organic carbon (TOC) tests are commonly used to indirectly measure the amount of organic compounds in water and are used in examples of the present invention to measure the performance of the composition in water treatment.

[0017] The composition may comprise only the polymer or a combination of the polymer and other materials, depending on the condition of the water to be treated and the requirement of the treated water. Other materials may be any water treatment materials, such as coagulant, surfactant, precipitant, and dispersant.

[0018] In some embodiments, the composition having a homopolymer of the second monomer is used for water treatment, i.e., the weight percentage of the first monomer to the total of the first and the second monomers is 0.

[0019] In some embodiments, the composition includes a copolymer of the first and the second monomers, i.e., the weight percentage of the first monomer to the total of the first and the second monomers is in a range of from greater than 0 to about 90%, such as, about 50%, or from about 25% to about 90%.

[0020] In some embodiments, a=0 and the first monomer is divinyl benzene of formula:

[0021] In some embodiments, R² is -CH₃ and the first monomer is trimethylolpropane trimethacrylate of formula:

[0022] In some embodiments, the second monomer is of formula:

[0023] The composition may be contacted with water in any suitable ways. In some embodiments, the contacting is by flowing the water through the composition, e.g., while the composition is filled in a column through which the water passes. In some embodiments, the contacting is by mixing the composition with the water.

[0024] In some embodiments, the polymer is an adsorbent for adsorbing, e.g. water soluble organic compounds. After contacting the composition and the water for adsorption, the composition is separated from the treated water which exhibits a reduced chemical oxygen demand.

[0025] The polymer may be of any suitable form including, but not being limited to, powder, bead, fiber, or a porous or non-porous bulk. As used herein, the term "bead" refers to a material in the shape of sphere with certain diameter. In some embodiments, the polymer is in the form of beads with a diameter of no less than about 100 micrometers, such as in a range of from about 500 micrometers to about 1,000 micrometers, or from about 500 micrometers to about 1,200 micrometers, or from about 500 micrometers to about 1,500 micrometers.

[0026] As used herein, the term "bulk" refers to a mass of material without certain shape. In other words, it may be a block, a flat piece or other nonspecific shape.

[0027] In some embodiments, the polymer is in the form of beads prepared by mixing an aqueous phase and an organic phase. In some embodiments, the stabilizer in the aqueous phase for preparing the beads comprises, but is not limited to, poly( vinyl alcohol) (PVA), cellulose or any derivative thereof, gelatin, sodium poly(meth)acrylate, hydroxyapatite, magnesium carbonate, or any combination thereof. In some embodiments, the optional surfactant in the aqueous phase for preparing the beads includes, but is not limited to, tween-80, tween-20, sodium dodecylsulfonate (SDS), sodium dodecylbezene sulfonate (SDBS). The term "optional" or the like refers to the situation that in some embodiments, the surfactant is used and in other embodiments, the surfactant is not used.

[0028] Besides the first and the second monomers, the organic phase for preparing the beads includes an initiator and an organic solvent. Examples of the initiator include, but are not limited to, 2,2'-azobis(2-methylpropionitrile) (AIBN), benzoyl peroxide (BPO), peroxide, a redox initiator, or any combination thereof. Exemplary organic solvents include, but are not limited to, toluene, ethyl benzene, xylene, anisole, C5-C 12 alkane, paraffin oil, or any combination thereof.

[0029] The ratio of the aqueous phase to the organic phase may be in a range of from about 1 :2 to about 2: 1 and the polymerization may be performed at a temperature in a range of from about 70°C to about 90°C.

[0030] The first monomer and the second monomer are low in costs thereof, so the polymer is economic. The polymer may be regenerated either by washing with excess amount of alcohol or by low temperature (120°C to 190°C) steam regeneration. Therefore, the polymer can be regenerated on-site and reused multiple times for applications such as water treatment and further reduce the cost of the water treatment.

[0031] As can be seen from the following examples, the preparation process of the polymer is simple and the polymer can be easily regenerated and has good adsorption performances in water treatments before saturation and after regeneration. EXAMPLES

[0032] The following examples are included to provide additional guidance to those of ordinary skill in the art in practicing the claimed invention. These examples do not limit the invention as defined in the appended claims.

Example 1

[0033] Trimethylolpropane trimethacrylate (5g, "trimer") of formula:

and 0.04g 2,2'-azobis(2-methylpropionitrile) (AIBN) were dissolved in 12ml Ν,Ν'- dimethylformamide (DMF) in a 40ml ampoule. Certain amount of poly(ethylene oxide) (PEO), β-cyclodextran (β-CD), or Hypermer2800, based on the weight percentage (wt%) of the trimer (trimethylolpropane trimethacrylate) was added as porogen, for example, 0.02g PEO (0.4wt% of the trimer (trimethylolpropane trimethacrylate)) in experiment Run 2.

[0034] The vessel was sealed with a septum and the homogeneous mixture was degassed thoroughly by bubbling argon for 5minutes. The polymerization was initiated by putting the vessel into an 80°C oven overnight. White/pale yellow monolithic product was crushed into powder, and then purified with excess amount of ethanol and hot water.

[0035] The porogens, the weight percentages of porogens with respect to the trimer

(trimethylolpropane trimethacrylate) and molecular weights (MWs) of porogens are listed in table 1 below. The B.E.T specific surface areas, the pore volumes and the average pore sizes of the purified powder were measured and are listed in table 1 below. Table 1

[0036] Representative organic compounds were measured by weight, mixed together with water, and stirred for minimum 1 hour before using as the synthetic water.

[0037] Mixing 2ml of water sample with the high range COD testing reagent from Hach, and heating at 150°C for 2 hours using Hach DRB200. After cooling down to the room temperature, the COD was measured by Hach DR500 or DR3900 spectrophotometer with programmed wave length.

[0038] Table 2 below shows the total organic carbon (TOC), chemical oxygen demand (COD) and the organic composition of the synthetic water. Table 2

[0039] The purified powder was mixed with synthetic water samples with 500 ppm TOC while a weight ratio of the synthetic water to the adsorbent powder (dry weight) was 100: 1. The initial COD of the synthetic water sample for experiment Run 1 was 1323 ppm, for each of Runs 2-5 was 1386 ppm, and for each of Runs 6-11 was 1426 ppm. The mixture was shaken for a few seconds initially and then left for 24 hours before analyzing the COD of the treated water.

[0040] The COD of the treated water and the COD reduction efficiencies of Runs 1-11 are listed in table 1 above, wherein the COD reduction efficiency (adsorption efficiency) was the percentage of the gap between the initial COD of the synthetic water and the COD of the treated water with respect to the initial COD of the synthetic water.

[0041] It can be seen from table 1 that the polymer of trimethylolpropane trimethacrylate was effective in reducing COD and the addition of porogen in polymerization improved the adsorption performance of the polymer, but there is no clear trend in terms of the effects of the dosage, molecular weight, and the type of the porogen to the adsorption performance.

Example 2

[0042] Monomers (dimer of formula:

trimer of formula:

and tetramer of formula:

were used to prepare the adsorbent material. The formulations and polymerization conditions used in experiment Runs 12-16 were similar with those of example 1, except the monomer compositions shown in table 3 below. The COD reduction efficiencies of polymers of different monomer compositions were tested with the synthetic water in the same way as that of example 1 , and results are shown in table 3 below.

Table 3

[0043] From the data shown in table 3 above, it can be seen that surprisingly the polymer derived from 100% trimer (trimethylolpropane trimethacrylate) had significantly better adsorption performances than polymers derived from the dimer (ethane- 1,2-diyl bis(2- methylacrylate) or the tetramer (2,2-bis(acryloyloxymethyl)propane-l,3-diyl diacrylate) either alone or in combination with the trimer (trimethylolpropane trimethacrylate).

Example 3

[0044] The polymer adsorbents prepared by copolymerizations of trimethylolpropane trimethacrylate (trimer) or trimethylolpropane triacrylate and divinylbenzene (DVB) with different ratios were tested in experiment runs 17-25 and the comparative run in ways similar to that of example 1 along with a commercial product Dowex Optipore™ L493 (DOW Chemical Company, USA) and related data are shown in table 4 below. The preparation and purification process of the adsorbents were conducted in ways similar to that of example 1.

Table 4

[0045] Table 4 shows that copolymers of trimer (trimethylolpropane trimethacrylate) and DVB had comparable or better COD reduction efficiencies than the commercial product L493 though with smaller B.E.T specific areas. Table 4 also shows that, surprisingly, although the trimer has only more hydrophobic methyl functional groups than the trimethylolpropane triacrylate, the copolymers of the trimer with DVB all had much higher COD reduction efficiencies than the copolymer of trimethylolpropane triacrylate and DVB.

[0046] The GC-MS method was used to measure the adsorption preference of adsorbents to dissolved organic compounds. The GC/MS was done with an Agilent 6890 GC FID instrument. The column of HP-Innowax was applied and helium gas was used as the carrier at 1.0 ml/min. The GC injection temperature was set at 250°C, split ratio: 20: 1, injection volume: 0.2 μΐ, FID heater temperature: 250°C, H₂ flow rate: 40ml/min, air flow rate: 450ml/min, make up gas N₂: 45ml/min.

[0047] Table 5 below illustrates the concentrations of organic compounds in water before and after the treatments of adsorbent polymers of runs 17-23 and L493. Table 5 shows that the adsorbent polymers were better at adsorbing polar organics like anisole, 2,6-dimethyl-phenol and octanoic acid than adsorbing volatile organic compounds (VOCs) like acetone and pyridine. In some formulations, the performances of adsorbent polymers were better than polymers of different chemical composition such as L493.

Table 5

Example 4

[0048] A 500ml kettle reactor was equipped with a mechanical stirring rod, rubber septum and cooling condenser. Poly vinyl alcohol (PVA) solution (1.2wt%) was prepared by dissolving 6g PVA (MW=67,000, 88% hydrolyzed) into 500ml water.

[0049] The aqueous phase of experiment run 31 was prepared with sequential addition of 20g 1.2% PVA solution, 130g DI water and lg 45% sodium polymethacrylate water solution. The obtained mixture was kept stirring to achieve a fully homogeneous solution.

[0050] The organic phase of experiment run 31 was prepared in a separate bottle. AIBN (0.3 g) and 0.2g benzoyl peroxide (BPO) were dissolved by 80g toluene, then 20g trimer and 20g DVB with 80% purity were weighed into the same bottle, the mixture was shaken to a homogeneous liquid.

[0051] The organic phase was added into the aqueous phase to obtain a reaction mixture. The reaction mixture was then degassed by bubbling Ar for 30 minutes under stirring. When the degassing was finished, the reaction mixture was heated in an oil bath to 80°C to initiate the polymerization reaction. The reaction was kept at 80°C for 5 hours and then raised to 90°C for 1 hour to consume the residual monomers. The polymer beads were poured into excess cold water in a 500ml baker, washed thoroughly by excess amount of ethanol and then rinsed by water. The polymer beads were purified in 75°C water for at least 24 hours, occasionally changing to fresh water.

[0052] Experiment runs 26-30 were conducted similarly as run 31 except some or all of the solvent, solvent amount, water amount, initiator, initiator amount, stabilizer, stabilizer amount, surfactant in the aqueous phase, temperature, and stirring rate were changed. All experiment parameters of runs 26-31 , and product characteristics and performances thereof are listed in table 6 below.

Table 6

Example 5

[0053] The adsorption and regeneration (desorption) performances of adsorbent beads made in Run 31 was evaluated on a steel fixed-bed column with 1.6cm inner diameter and 14cm height for 12 continuous cycles. Each cycle includes the adsorption of the adsorbent beads in the 1500ppm TOC synthetic water and regeneration (desorption) of the adsorbent beads with 120°C steam being applied.

[0054] The bead loading volume was between 30-45g. The synthetic water with initial TOC level of 1500ppm was pumped into the column in a down-flow direction running through the adsorbent beads at a lOg/min rate for adsorption before saturation. The desorption of organic compounds was performed by flowing steam through the column bed as generated from a boiler with pre-set temperature. The complete point of desorption was determined by the COD measurement of column outlet effluent, i.e., when organic compounds could no longer be detected coming out of the column.

[0055] Samples were collected at regular intervals to measure the outlet TOC concentrations.

[0056] The weights of TOC in each adsorption and regeneration cycle were recorded. The weights of adsorbed TOC and desorbed TOC of each cycle and the average values of the 12 cycles are listed in Table 7 below. The data show that the adsorbed organics could be

consistently recovered using 120°C steam, so the adsorbent was effectively regenerated.

Table 7

[0057] B.E.T measurements of table 8 below show that the specific surface area (B.E.T), the pore volume and the average pore radius of the adsorbent material made in run 31 before and after 12 cycles were relatively identical, indicating the adsorbent material is quite thermal and mechanically stable under the regeneration conditions.

Table 8

[0058] FIG.1 illustrates the TGA analysis of the sorbent bead made in experiment run 31 and shows there was no obvious thermal decomposition of the adsorbent bead before 250°C.

[0059] Mechanical strength testing show adsorbent beads made in experiment run 31 with 0.5mm diameter were not crushed under 450g force, and with 1mm diameter resisted 1kg force.

[0060] While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

1. A method for water treatment, comprising: contacting water with an effective amount of a composition comprising a polymer derived from a first monomer of formula I:

and a second monomer selected from:

obtain a treated water with reduced chemical oxygen demand; and separating the treated water from the composition, wherein: a weight percentage of the first monomer to a total of the first and the second monomers is in a range of from 0 to 90%;

R¹, independently at each occurrence, is, H, Ci-Cig alkyl, alkoxyl, or phenyl;

R² is Ci-Cig alkyl, alkoxyl, or phenyl; and a is an integer ranging from 0-4.

2. The method of claim 1 , wherein the weight percentage of the first monomer to the total of the first and the second monomers is 0.

3. The method of claim 1 , wherein the weight percentage of the first monomer to the total of the first and the second monomers is 50%.

4. The method of claim 1 , wherein the weight percentage of the first monomer to the total of the first and the second monomers is in a range of from 25% to 90%.

5. The method of claim 1 , wherein the polymer is in a form of beads.

6. The method of claim 1 , wherein a=0.

7. The method of claim 1 , wherein R² is -CH₃.

8. The method of claim 1 , wherein the contacting is by flowing the water through the composition or mixing the composition with the water.

9. The method of claim 1 , wherein the second monomer is of formula:

10. The method of claim 1, wherein the polymer is an adsorbent.

11. A composition comprising:

a polymer derived from a first monomer of formula I:

a second monomer selected from:

wherein: a weight percentage of the first monomer to a total of the first and the second monomers is in a range of from greater than 0 to 90%;

R¹, independently at each occurrence, is, H, Ci-Cig alkyl, alkoxy, or phenyl;

R² is Ci-Cis alkyl, alkoxy, or phenyl; and a is an integer ranging from 0-4.

12. The composition of claim 1 1 , wherein the second monomer is of formula:

13. The composition of claim 11, wherein the weight percentage of the first monomertal of the first and the second monomers is in a range of from 25% to 90%.

The composition of claim 11 , wherein

15. The composition of claim 11, wherein R² is -CH₃.

16. The composition of claim 11, wherein the polymer is in a form of beads.

17. A method, comprising : preparing an aqueous phase comprising water, and a stabilizer; preparing an organic phase comprising an initiator, an organic solvent, a first monomer of formula I:

and a second monomer selected from:

and

mixing the aqueous phase with the organic phase for polymerization to obtain a composition in a form of beads, wherein: a weight percentage of the first monomer to a total of the first and the second monomers is in a range of from 0 to 90%;

R¹, independently at each occurrence, is, H, Ci-Cig alkyl, alkoxy, or phenyl;

R² is Ci-Cis alkyl, alkoxy, or phenyl; and a is an integer ranging from 0-4.

18. The method of claim 17, wherein a weight ratio of the aqueous phase to the organic phase is in a range of from 1 :2 to 2: 1 and the polymerization is at a temperature in a range of from 70°C to 90°C.

19. The method of claim 17, wherein the stabilizer comprises poly(vinyl alcohol) (PVA), cellulose, gelatin, sodium poly(meth)acrylate, hydroxyapatite, magnesium carbonate, or any combination thereof.

20. The method of claim 17, wherein the organic solvent comprises toluene, ethyl benzene, xylene, anisole, C5-C₁₂ alkane, paraffin oil, or any combination thereof and wherein the initiator comprises 2,2'-azobis(2-methylpropionitrile) (AIBN), benzoyl peroxide (BPO), peroxide, a redox initiator, or any combination thereof.