CA1056531A - Water-in-oil sulphonated polymer liquid membrane formulation - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A water-in-oil emulsion comprising (a) a sulfonated polymer. said sulfonated polymer comprising a backbone which is substantially nonaromatic; or an ethylene copolymer comprising at least 25% by weight ethylene and (b) a solvent for said sulfonated polymer or said copolymer as the oil phase of the emulsion.

Description

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This application is directed to water-in-oil emulsions wherein the oil phase includes specific sulfonated polymers and the use of those emulsions. Divisional application S.N. ~ 34 filed ~ e~ 17 is directed to water-in-oil emulsions wherein the oil phase includes specific ethylene-vinyl alkanoate copolymers and the use of those emulsions.
This invention relates to novel liquid membrane formula-tions which are water-in-oil emulsions wherein the oil phase comprises a sulfonated polymer having a backbone which is substantially non-ln aromatic, for example, less than 10 mole % aromatic, and uses thereof in high temperature liquid membrane processes. The emulsions are useful in liquid membrane water treating processes, especially in water treating processes which are desirably run at high temperatures.
In the most preferred embodiment, these compositions are used in a liquid membrane sour water treating process wherein a waste water stream containing ammonium sulfide is contacted with a liquid mem-brane emulsion, i.e. the emulsions of the instant invention, at conditions whereby ammonia permeates through the external phase of the emulsion into an acidic internal phase wherein it is converted to a nonpermeable form, e.g. ammonium ion, while H S is continuously stripped out of the waste water solution by means of an inert gas, e.g. steam. Processes of this sort are most effectively carried out at temperatures greater than 80C. wherein the emulsions of the instant invention have excellent stability.
In German Patent Publication 2,434,590 published February 6, 1975, a process for removing the salt of a weak acid and a weak base from solution by means of the liquid membrane technology disclosed in U.S. patents 3,410,794, 3,617,546 and 3,779,907 is disclosed. The process disclosed in DOS 2,434,590 utilizes the liquid membrane technology to remove either the weak acid or weak base or their hydroIysis products from solution by permeating through the e~ternal phase of the liquid membrane emulsion, and converting same into a nonpermeable form in the ~,3~ i~
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interior phaseJ Simultaneou~ly the weak acid or weak ba~e or hydrolysis product thereof may be ~tripped from solution by 3 means of an inert gas or alternatively by subjecting the ~ys~
4 tem to subatmo pheric pres~ures. ThiR process has been found to ba most effective when run at high temperatures, for ex-6 ample, 80C. It has been found, however, that3 a~ temper~-7 tùre~ in thi~ range, many liquid membrane orm~1ations, iOe.
8 water-in-oil emulsions, are unstableO In the process o~ th~s 9 invention, thi~ problem i~ ~olved b~ means o no~el ormuLa-tions which have been ~ound ~o be stable at temperatures up l ~o 100C.
12 The instant invent~on relates to novel liquid mem-13 brane formulations whieh are water~in-oll emul~ions wherein said oil phase compri~e~ a sulfona~ed polymer havlng a back~
bone which is sub~tanti~lly nonaromatic The~e novel compo-16 ~itions also comprise a solvent for ~aid ~ulfonated polymer 17 which is immiscible with waterD and although not necessary, 18 an oil-soluble surfactant may also be used in the ormul~tion~
l9 The aqueous interior phase of these emulsions may c~mprise a base or an acidO Th8 emulsions of ~hi in~ention are espec-21 ially suitabla for use in liquld membrane prooesse~ wherein 22 aqueous solutions are treated at high temper~ures with liq-23 uid membrane formulations. Furthermore9 whe~ these emulsions 24 are being utilized in the preferred process for treat~ng sour water~ the emulsions will usually c~prise either a strong 26 acid or a regenerable acid The regenerable acids used in 27 forming the compositions of the inæ~ant invention are fully 28 described in DOS 2,4349590, 29 In general, sulfonated polymers which are useful in the compos~tions and proces~ of th~ inst~n~ in~ention are dis~

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1 closed and claimed in U S. Patent 3,64~728. The

2 term "substantially non-aromatic in

3 nature" means that the backbone will comprise less than 25

4 mole %, preferably less than 10 mole % aromatic groups~ This is a necessary limitation since i~ has been found9 unexpected-6 ly, that aromatic~containing sulfonated pol~mers do not form 7 stable emuL~ions with the solvent systems utilized in cer 8 tain higher temper~ture liquid membr~ne processes9 e g.
q liquid membrane sour water treatingO
The pre~erred sulfonated polymers of the ins~ant in-11 vention are selected from the group eonsi~ting of sulfona~ed 12 butyl polymers and ~ul~onated ethylene-propylene copolymers.
13 Most preferably, compositions of the instant invention com-14 prise ~ sulfon~ted butyl polymer~ The butyl polymer is pre-pared by copolymerl2ing isobutylene and isoprene, op~ionally 16 with a third monomer, e~g~ cyclopenta~iene~ The preferred 17 sulfobutyl polymers of the inst~nt invention will contain 18 from about o25 to 10 mole % sulonic acid groups, more prefer-19 ably from about ~5 to 5 mole % sulfonlc acid groups. Thls copolymer m~y be prepared by the method~ described in U~SO
21 Patent 3,642,7280 The preferred $ulfobutyl polymer of the 22 instant invention will have a number ayerage molecular weight 23 of at least 1,000~ preferably from 5,000 to 50~000~
24 Other sulfonated polymers which are useful in making the compositions of the in~tant invention may be selected 26 from the group consisting of sulfonated copolymers of iso-27 butylene and piperylene~ isobutylene and cyclopentadiene, lso-~8 butylene and methylcyclopentadiene, and isobu~ylene and beta-29 pinene. The diene content of these polymers may range from

5 to 30%, preferably 1 to 25 mole %0 Various sulfonated ter ~' -- 4 ~

lOS6S31 polymers are also use~ul in preparing the compositions of the 2 instant inventionO For example, i~obutylene may be s:opolymer-3 ized with any two of the above eonjugated dienes and the re-4 sulting copolymer sulfonated in accordance w~th the teachings s of U.S, Patent 3,642 9 728 to yield sulfonated polymers useful

6 in the instant invention.

7 Other less preferred copolymers for use in the in-

8 stant invention are prepared by copolymeri~ng ethylene and

9 propylene with a diene, e~g~ dicyclopentadiene, e~hylidene lo norbornene~ or 196-hexadiene and sulfonating ~he copolymer 11 as described above~ These ~erpolymer~ may have from o2 to 12 10 mole % unsatura~ion and mo~e prefer bly from .5 to 7%
13 prior ~o sulfonation.
14 Finally, highly unsaturated nonaromatic polymers may be sulfonated and used in preparing the compositions of l6 the instant invention. For ex~mple, polybutadiene and poly-17 isoprene homopolymers may be so utilizedO
18 The polymers de~cribed above7 ~n general, will con-l9 ~ain from .25 to 20 mole % ~ulfonic acid groups3 preferably from ~5 to 5 mole % sulfonic acid group~, and have a number 21 average molecular wei8ht of a~ leas~ 19000, preferably from ~2 5,000 to 50~00O
23 The use of emulsions prepared from sulfonated 24 polymers is not re~tricted to sour water treatmentO They have 2s a very wide utili~y in other liquid membrane proee~ses. In 26 systems in~olving strong acids andjor bases9 these emulsions 27 are particularly advanJcageou~ since the ulfonated polymers, 28 described abo.re, act as emulsifying agents9 and ~like D~any 29 surfactants are not prone to hydrolysis under ~he conditions 30 of use.

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1 In cases where high temperatures and strong ~cids 2 or bases are used~ it is essential that solvent for the sul-3 fonated polymer be selected judiciou~ly~ Thus a solvents such 4 as esters which can hydrolyze easily shDuld not be usedO
5 Another restrlction is volatility o solvents. Thus, hydro-6 carbons and other ~olvents which are volatile at 80C~ or are 7 steam distillable cannot be usedO Another criteria for se-8 lection of sol~ents in water-treating processes is toxici~y.
9 Solvents which le~ve a to~ic residu~ ~n water m~st be avo~ded.
It is also important that solvent~ used ~n this process ~hould 11 be liquids under the operating conditions ~o provide liquld 12 membranes and should no~ have a tendency to solidify during 13 u~e~ The solvent should also be selected so that the speci-4 ~ic gravity of the formu~ted emulsion differs from that of the feed s~rsam, with which it is to be contacted, by at least 16 .025, to allow easy separation Qf ~he emulsion from the feed.
Thus~ if the difference between the specific gr~vity of the 18 feed stream and the emulsion is too ~m~ll9 the separation 19 thereof ls a time eonsuming process~ Other con~ide~ations will be apparent to tho~e skilled in the ar~ For the reasons 21 given ab~ve, the pref~rred solvent will be chosen from the 22 following group:
23 Petroleum distilLate~ having a boiling point of 24 ~200C. ~igher boiling normwl p~raffins which have a melt-ing point of ~0C. or more should ~ot be usedg unless they 26 ar~ m~xed with other solvent~ ~o lowar their melting points.
27 Paraffinic solvents, which may be lightly substituted wi~h 28 haloge~s such as chlorine or benzene or cycloalkyl ring~, 29 i~e. less than lO mole %~ Preferred solven~s include the petroleum distillate~ known a8 isoparaffins hav~g an average ~ O S6 S 3~
1 carbon number of from about 10 to about 100, mos~ preferably 2 from 30 to 75. ~xamples of solvents of ~his type are the re-3 fined isopar~ffins known as Solvent Neutral* types, av~ilable 4 from Exxon Chemlcal Company Almost all of these are suit-able in the instant invention, e~g~ Solvent Neutral*100, 6 Solvent Neutral*150, Solvent NPutral*~OO and the various 7 grades inbetween. (The numeral re~ers to ~he SUS viscosity 8 at 100F.) Other petroleum ~ract~on~ such as bright stock, 9 Coray 90 and tha l~ke are al~o 8uitableO These are petroleum lo lubricating oils having viscosities of 47904 and 41202 centi~
11 stokes, respect~vely, at 100F. ~n msny applications, it 12 may also be desirable to u~e mixed so~vents such as, for l3 exampleg Solvent Neutral 100 and Sol~ent Neutral 600, in 14 combination.
The most preferred form of the sulfonated polymers 16 used in preparing the compositions of the instant invention 17 is the free acids9 although long chain ~mines or polyamines 18 can be used as neutralizing agentsO ~e amine~ useful as 19 neutralizing agent3 include triamlnes, e.g. cont~ining C6 to C16 hydrocarbyl rad~cals~ such a~9for e~ampleg ~rioctylamine;
21 and-diamines, e.g. conta~ning C~ t~ C16 hydrocarbyl radical5 22 such as, or example9 didodecylamine. The ~mines are se-23 lected on the basis of their Lack of solubility in water. If 24 these amines or the~r s~lts h~ve appreci~ble solubility ~n water, they are li~ely to be los~ when strong acids ~nd bases 26 are utilized in the intern phase~
27 As will be described later9 ~alts of these sulfonic 28 acids ~uch as ammonium~ potas~ium, sodium9 etc., are not 29 particularly useful in these applications due to the lack of their solubility ~n the solv~nt system used.

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0 5 ~ 5 3~
~ The pol~ner8 containing ree ~ulfonic acid groups 2 are prepared by fir~ .ul~onating the copol~mers such ~s, for 3 example, isobutylene isoprene copolymer And then replacing 4 the solvents us~d in their preparation such as methylene chloride, volatile hydrocarbons and the methanol quenching 6 agent by the solvent desirable for emulsion formation9 e.g~
7 Solvent Neutral*lO0 or Sol~ent Neutral*G000 This proce~s is 8 kno~ in the art as solYent replacementO Another method is 9 t~ neutralize the s~lt~ of the~e sulfonic acid polymers with an acid, e.g. sulfuric acid~ and extract the polymer with the 11 desired solvent~ Sollltions o these polymers when stored in 12 amber-colored bottles are indefin~tely stable~ The concen-tration of the sulfonic acid polymers used in preparing the compositlons of the instant invention m~y vary from 0,~5 to 40 wt~ %, preferably frçm O-l to 30 wto %~ in the solvent.
16 In many liquid membrane processes9 such as sour 17 water treatmen~, it is de~irable to maximi~e r~te of ammonia 18 transfer to internal phase as well as the removal of H2S by 19 the inert gas, e,g. steam, or by subatmospheric pressures, This is accomplished by carrying out the proce~s at temper-21 atures higher than ambient w~ere~n the vapor pres~ure of H2S
22 increases substantially and its solubility in water Is d~-23 creased~ Thus9 the solubility of H2S in w~ter at 25 is ~34%
24 and at 90C. it is 09 04%O It is evident that when running this process at a~mospheric pre~$ure~ a temperature of 80 to 26 85C. would be ver~ practical~
27 One of the outstanding advantages in using ~he sul-28 fonic acid polymers de~cribed above i~ th~t no ~dditional sur-29 factant is-needed to stabili~ the emuLsion; thus, risk o~
hydrolysis and/or decomposition at higher operQting tempera-5, -, .
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tures i8 avoided. ~he sulfona~ed polymer~ provi~e both addi-2 tive and sur~actant properties needed in the liquid membrane 3 processes, Also, ~he sulfonic acid polymer~ possess the 4 proper hydrophilic-lipophilic balance a~ ~he operating temper-atures~ e~ tempera~ures of from 80 to 100C~ It h~s been 6 noted that unlike m~ny other dditive~9 e.g~ polyi~obutyl-7 succinlc anhydride-tetracthylenepentamine, commonly used at 8 the operating ~emper~tures described above~ the sulfonic acid 9 polymers are inert to hydrogen sulfide attack" in liquid mem-brane proce~ses, 11 All of the above factors mak2 the ~ul~onlc acid 2 polymers de~cribed above p~rt~cuLarly suitable or forming 13 emulsions~ useful ln high ~emparature liquid membrane pro-14 ces~es espec~lly liquid membrane ~our wa~er ~reating pro-cesses.
16 The aboYe co~ponents~ that is sulonated polymerD
17 solvent with or without a surfactantg are selec~ed with con-18 sideration of ~heir interaction to ~orm emul~ion~ wh~eh are 19 stable at high temper.tures and espec~lly in the presence of 2a strong acids and bases~ The choice of specific combinstions 21 is within the skill o the art~san ~n the ield o~ emulsion 22 technology with the te ching of thiæ disclosure before him.
23 In general, the emulsions of the instant invention are pre-24 pared by technique~ known in the artO For example, the sulfonated polymer may be dissolved in the ~olvent foll~wed 26 by the addition and dissolution of the ~urfac~ant. However, 27 the components ~an be combin~d in any order. ~he aqueous in-28 ternal pha~e msy then be added to the oil ph se while ag~tat 29 ~ng wi~h any of the de~ices known in the ar~ for prepar~ng stable emulsion~. For example~ paddleæ with a ~tirrer oper-, 105653:~L
1 able at h~gh speeds msy be used to emulsify the components.
2 Other well~known emulsion-forming techniques which 3 may be utilized include the use of colloid mills in which 4 large droplets are broken up by the intense shearing forces.
Homogenizers can also be used after a preliminary emulsifica-6 tion in a mixing ve~el~ colloid mill, or other device~ In 7 this type of operation, the coarse emulsion is pumped at a 8 high velocity`through the annular opening o a valve, The 9 droplets are di8rupted~ par~ly b~ the simple ~ eving action"
0 and partly by the intense shearing forces ~hich are set up 11 in the annulus~ Other e~ul~ifying devlees res~mble the in-12 tense types just descr~bed9 such as speclal mixing pumps, 3 centrifugal emulsifiers, ultrasonic generator~9 slotted 14 mixers, mixing jet~ including those in which ultra30nic 15 vibration occurs and turbulent 10w device~ ~n which a coarse 16 emu~sion i5 made to flow along a tube at a speed greater than 17 the critic~l velocity for ~urbulence.
18 In generalD the compositions of the instant in~ren-19 tion ~ill comprise from lO to 90" preferably 30 ~o 60 wt. %
oil phase and the r~mainder ~he aqueous internill phase.
21 The internal phase may com~rise a strong acid or 22 a stron~ base or any of ~he other re~gents described in UvS~
23 Patent 3,779~907. ~lowever, these emulsions, as stated above, 24 are especialLy useful in the process de~cribed in DOS
2,4349590. Thus9 preferablyg in the compo~ition of the in-26 stant invention, the internal phase, is a~ described therein.
27 Most preferably the internal phase will comprise either an 28 acid ~strong or regenerab?~) or a strong ba~e. The con-centration of acid or bas~ in the internal pha~e of the emul-sion i8 adjusted 80 that the emulsions may be u~ed aconomic-.. 10 -1~)5ti531 1 ally. In general~ the concentration ls as high a~ pos~ible, 2 even up ~o saturation~ taking into considerat~on ~he stabil~
3 ity of the emulsion9 eOg, from l ~o 30% by Meight concentra-4 tions may be used~
The instant invention fur~her relates to novel liq-6 uid membrane formulations, i.e., emulsions9 which comprises 7 an aqueous in~erior phase and a water-imm~cible exterior 8 phase, said water-immiscible exterior phaae comprising an 9 ethylene vinyl acetate copolymer and a ~olvent o~ the type 0 describ~d above for this polymerO These composi~ions pre-11 ferably add~t~onall~ contain a w~ter ~nsoluble $urfactant to 12 s~abilize the emulsionsO In a preferred embodiment" the 13 aqueous ~n~erior phase comprises a strong acid, for example, 14 from l to 30, preferably about l to about lO percent by weight sulfuric acid. These emulsions are useful in liquid 16 membrane processes for the ~ep~ration of dis~olved components 17 from aqueou8 solution9 Emulsions o the instant inven~on 18 are characterized as showing ~ery lo~ swelling when contacted 19 with aqueou~ solutio~s, e~pecially at higher ~emperatures and thus are especially effectlve ~or use ~n the trea ment of 21 sour water feed streams by the liquid membrane technique.
22 In liquid membr~ne processes, the emul~ion is 23 brought into contact with an aqueou~ feed stream containing 24 a dissolved material which is to be removed by permeation through the external phase of the emul~on (liquid membrane) 26 into the internal phase, at condition~ of constant agita~ionO
27 The emulsic~ i ~hen 3epara~ed by discontinuing ~he agitation ~8 and allowing the emul~ion to settle. The emulsion~ u~eful in 29 water treating processes are characterized a~ wa~er-in oil ~ emu1slons and may be ~tabilized by incorporating an oil-.

105t;531 1 soluble surfactant in the ex~ernal phase of th~ emulsion.
2 Due to the hydrophilic and lipophllic nature of the surfac-3 ~ant, rapid settling of the emulsion after cont~ct with the 4 aqueous feed stream is not alw~ys obtained. Furthermore, the emulsion9 especially when contacted with the aqueous 6 feed stream at high temperature~, ~or e~ample ~0C~1 has 7 been known to swell and in certain cases the entire mass, 8 i~e. feed stream and emulsion, h~s gelled, Finally~ it has 9 been noted in certain liquid membrane proces~es that after settling of a subs~antial portion of the emu~sion the aqueous 11 feed stream is left hazy due to the formation o~ very sm~ll 12 emulsion partlcles9 which do no~ ~ettle with the bulk of the 13 emulsion, When the liquid membrane proces~ is utili~ed for 1~ water pollution abatement~ haz~ne~s remaining in the treated water is completely unacceptableO
16 The compositions of the in~tant in~ention may be 17 used in liquid membrane water treating processes to solve all 18 of the above problemsO The ethylene vinyl acetate copolymer 19 which is used in forming ~ composition of the instant inven-tion is characteri~e~ ~s having a molecular weight of from 21 about 500 to about 100~0009 preerably from abou~ 500 to 22 109000. Thcse polymers may be prepared by copolymerizing 23 ethylene and vinyl acetate in a free radical process at hlgh 24 temperature and pressure. The polymers may be prepared by the proce~s described in U~SO P~ten~ 3,638,349 and 26 German Patent 1,914,756. The percentage 27 of vinyl acetate in these copolymer~ may vary ~rom l to 75 28 percent, but is pre~erably between 5 to 40 percent by weight.
29 In the above polymerization, in place of vinyl acetate, other esters of vinyl alcohol contain~ng from l ~ ~J~

1~5653i 1 to ~O carbon ~tom~ in the al~anoate portion of the ester m~y 2 be u9ed, Ex~mple of ~uch monomer8 include vinyl formate, vi-3 nyl propionate9 vinyl neopentanoate, vinyl hex~noate, vinyl 2-4 ethyl hexanoate, vinyl decanoateg ~inyl laurate, vinyl stear-5 ate7 vinyl benzoate, vinyl salicylate5 vlnyl thiolacetate, 6 vinyl pivalate9 vinyl neodecanoate and th~ likeO Similarly, 7 esters of a~rylic acid and methacrylic acid msy be copolymer-8 ized with ethylene in place o~ or in combination with the a-9 bove vinyl esters. Exampl~s of such monomers lncluda methyl-o acrylate, ethyl acrylate, butyl acrylate, t-butyl acrylate,do-11 decyl a rylate, dodecyl methacrylate, 2-ethylhexyl methacryl-12 ate, methyl methacrylate and the likeO In this case, acrylic 13 acid and methacrylic acid can al~o be used in place of or in 14 corr~bination with the above acrylic and me~hacrylic esters~
15 M~ny other vinyl monomer$ ~an be cspolymeriæed with ethylene 16 and will be apparent to tho~e sk~lled in ~he art~ Non~vinyl 17 monomers such as allyl acetate and i~aconic acid can al80 be 18 used~ The materials obtained by copol~merizing more than one 19 monomer al~o yield terpolymers ~uitable in this application, such as for example ethylene in combin~tion with vinyl acetate 21 an~ methacrylic acid9 vinyl propionate and methacrylic acid, 22 vinyl acetate and dibutyl fumara~e; vinyl acetate and mono-23 octyl maleate pr~vide copolymers useful in ~hi~ inventionO
24 The only limita~ion on the above polymers is that they contain at least 25%, preferably from 25 ~o 75%, by 26 weight ethylene in comblnation with a polar monomer copolymer-27 izable therewith. Thi8 polar monomer is n~ce~sary to achieve 28 the proper ~ydrophilic-lipophilic ratio in ~aid copolymer.
29 The oil-soluble suractan~; wh~ch may be used include anis~nic, ca~cionic, or nonio~ic ~urfactantsO
31 Anionic surfact nts us~ful for the process o thc 1056S3~L

l instant invention include:
2 Carboxylic acids, including fatty acids, rosin 3 acids, tall oil acids, branched alkanoic acids~ etc.
4 Alkali metal alkane and alkylaryl sulfonates, in-cluding alkyl benzene sulfonates, alkyl naphthalene sulfon-6 atés, etc, 7 The cationic surfactants use~ul for preparing the 8 composi~ions of the instant invention include:
9 Quaternary amine salt~.
lo Nonionic surfactants which ~re the preferred sur-ll factant type for preparing the compositions o the instant 12 invention, include the polyethenoxy-ether derivatives of alkyl phenols, alkylmercaptans, and alcohols, e~g., sorbitol, pentaerythritol, etc~
Partlcular preerred nonionic surfactants for use l6 in the instant invention include compounds having the 17 general formula l8 ~ lcH2cH2o]m - CH2CH2OH
l9 wherein Rlo may be C8H17, CgH1gg or ClOH21 and m is an in te~er varying from 1.5 to 8.
2l The most preferred nonionic surfactant is Span*80 22 manufactured by the Atlas Chemical Company~ a fatty acid ester 23 of anhydrosorbi~ol~
24 Since the n~mber of surfactants is extremely large, it is not intPnded to burden this appli~ation with numerous 26 examples. The following publications may be referred to for 27 further examples: Surf -- Cb$~i~sEy by Lloyd I. Osipow, 28 Reinhold Publishing Companyg New York (1962) chapter 8 and 29 Surface ActivitY, Moilliet et al, Van Nostrand Company, Xnc.
(1961) Part.III.

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l Generally~ the aqueous interior phase will comprise 2 from 10 to 80 volume % of such an emulsion, preferably ~rom 3 20 to 60 volume %.
4 The surfactant may be incorporated in the external phase of the emulsion at from 0.01 to 20, preferably ~rom 1 6 to 5 weight %~ The copolymer will be incorporated in sald 7 external phase at from 1 to 409 preferably from 3 to 30 8 weight %.
9 The following are speciic embod~men~ of the in-stant invention.
~i EXAMPLE 1 12 To a vigorou31y stirred (1~000 to 2,000 RPM) so-l3 lution o~ 13.6 g~ of butyl rubber sulfonated to 2% level in l4 186 5 gO of Solvent Neutral*100 at 85C. was added dropwise 186 ml of 10% aqueous sulfuric acid ~olution. 180 g. of 6 the emulsion thus produced was added with stirring (150 ~o 17 250 RPM~ to 740 ml of water containlng 19720 ppm of NH4~ as l8 ammonium hydroxide and 2,800 ppm of sulfide as H2S. Samples 19 of water solution were withdrawm by a pipette at 1 minute, 5 minute, 15 minute, 30 minute, 60 minute and 90 minute inter-2l vals by allowing the emulsion to ~ettle and taking a sample 22 -of lower aqueous layerO The tempera~ure wa~ m~intained at 23 80 to 85 ~hroughout the run.
24 The ammonium concentration gradu~lly decreased to 42 ppm in 30 minutes and the emulsion was stable over the en-26 tire length of experiment (90 minutes)~

28 The experiment in Example 1 was repeated. The con-29 centrations of NH4+ and S= were 1,700 ppm and 2~240 ppm7 re-spectively. In this experiment7 steam was passed at 85 C.

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1 through the m~xture w-lth stirring. The concentration o~ am-2 monium ions was rPduced in 30 minu~e~ to 34 ppm and sulfide 3 ions to ~20 ppm, The emulsion was again stable over the en-4 tire length of the experiment (90 minutes~.

6 The experlment given in Example 1 was repeated us-7 ing 2.5 wt. % of the sul~onated butyl rubber in the oil phase~
8 The internal phase ~ontained 2,13 wto % sulfuric acid. The 9 emulsion was contacted wi~h eed for 5 minu~e~, The concen-tration of NH4~ was determined at the beginning and end o~
11 the exp~riment, After this time~ the feed was removed and 12 the same emulsion was contacted with ~ fresh feed for 5 min-13 utes. The process w~s repeated two more times. The tempera-14 ture was maintained at 85C, for the entire leng~h of the ex-periment, The concentrations of NH4+ in the our feeds were 16 118, 137, 143 and 186 ppm and were reduced to 1~ 75 and 17 2 ppm, respectivelyO
18 This demonstrates the ~uitability of single emul-19 sion in repeated applications.

__ 21 The experiment given in E~ample 1 was repeated with 22 12% Lubrizol 3702 (a product of Lubri~ol Corp.) in place of 23 sulfonated butyl rubber in the formulation described therein.
24 The concentration of ammonium ions ~s 2,040 ppm and that of sulfide ions 1,970 ppm, Within 15 minutes of the st~rt o 26 the experimPnt9 the entire ma~s had gelled and samples could 27 not be withdrawn for ammonium analysis~

~ The experiment given in Example 1 was repeated with 4% PIBSA-TEPA, the reaction product of polylsobutylene-succin~

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l ic anhydride and tetraethylene-pentam me and 1% SPAN 80.
2 Within 15 minutes the entire reaction mixture had ge11ed and 3 it was not possible to withdraw s~mples for ammonium analysis.

The experiment given in Example 1 was repeated 6 with initial NH4+ concentration of 1,900 ppm but no H2S~
7 Within 30 minutes the concsntration o~ NM4+ wa~ reduc~d to 8 3 ppm.
9 Comparison o Efec~ivene~s of Polymers Sulfonated to Differ-~2 To a vigorously 3tirred solution of 1306 g. of 13 butyl rubber (copolymer of isobutylene with 5 mole % isoprene, 14 same as was used for preparing sulfonated polymers~ and 4 g.
of surfac~ant Span*80 in 182.4 gO of Solvent ~eutral*100 was 16 added, dropwise, 166 gO of 10% sulfuric acid solution. The l7 resulting em~lsion which looked normal at room temperature 18 wa5 heated to 85Co in order to carry out the tre~tment of l9 sour wAter. During heating9 ~he emulsion started breaking and as th~ tempera~ure reached 80Co organic layer separated 21 out completely from aqueous layer~ This demonstrates that 22 the emulsion does not pos~e$~ any ~tability under the oper~
23 sting conditlons even though an extern~l surfactant was 24 present.
EXAMPLE 8 - Polymer Sulfon~ted _ o Ie ~ 9~
26 ThP experiment given in Example 1 was repeated us-?7 ~ng the same concentration of butyl rubber sulfonated to 1 28 mole % level. The initial NH4f concentration of 1,960 ppm 29 was reduced to 4 ppm within 30 minutes and the emulsion was ~table over the length of ~he experiment (40 minutes)~

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2 The experiment given in Example 1 was repeated us-3 ing the same concentration of butyl rubber sulfonated to 4 4 mole % levelr The resulting emulsion was very thick. The initial NH4~ concentration in the feed was 2,040 ppmr Within 6 lS minutes the entire mas~ gelled and it was not possi~le to 7 carry out the experiment further.
8 ~lese experiments demonstrate that about 1 mole %
9 sulfonation is desirable in ~he sulonic acid polymers used in preparing the compo~itions o~ the instant invention;
ll levels greater than about 4% ~re not as e~fective.
12 The experimen~s g~ven in Examples 9, 10 and ll were 13 designed to determine the effect of a smaller amount of poly-14 mer sulfonated to 4% level9 on the stabill~y of the membrane?
EXAMPLE 10 ~ Pol er Sulfonated to a 4 Mole % Level 16 An emul~lon w~ prepare~ by enc~psulating 186 g. of 17 10% sulfuric aeid solu~ion in a ~olution of 1~5 g9 of bu~yl 18 rubber sulfonated to 4% level in 198.5 gg of Solvent Neutral*
19 100 at 85C, One~half of this emulsion was contacted with a feed solution containing 1~960 ppm of ammonium hydroxide in 21 the usual w~y. The emulsion had a tendency to stick too much 22 to the side~ of the re.ction ves~el and showed very poor 23 separability from the feed water. In e~fect9 quite a signif-24 icant part of the emulsion could not be made to eontact the feed solutionO In order for the emulsion to be workable, it 26 is important that the emulsion can be easily dispersed in the 27 form of tiny droplet~ so as to pr~vide a very large surface 28 area to effectively and rapidly remo~e any contaminant. In 29 ~his case ~he concentration of NH4+ was reduced to 80 ppm in 30 minutes but increased to 10~ ppm in 60 minutes~ indicating = ,i~

~0~;653~
1 a weakne~s of the membrane.
2 ~-P~ L ~ y~ Sulfonated t~ 8~5_a_L~Y~l 3 The e~periment given in Example 9 was repeated with 4 3.0 g, of butyl rubber sulfonated to 4% level instead of 1~5 g~ as given in the preceding example~ The concen~ra~ion of 6 ~H4~ in the feed was 2,1600 Th~s concentration wa~ reduced 7 to 90 ppm in 30 minutes. However, ~he emulsion gelled com-8 pletely in 55 minutes~
4 The3e experiments indicate that levels of sulfonated polymer of at le88t 1 wt, % in the external pha~e are desir-11 able.
12 Compari~n of Effectlvenes~ of Sulfon~ted Pol~mers with Di~-13 ie~ c~ We~

14 The experiments given in Examples 12-14 were de-signed to determine the effect of molecular weight on the mem 16 brane strength and sfficacy in treatment of sour water. It 7 was observed tha~ with concentration of polymer in the range 8 of 3 to 6% emulsions were very t~ick paætes and could not be 19 handled while the e~ul~ions containing very low concen~ration~
of sulfona~ed high moleeular we~ght polymer lacked dimension-21 al stabili~y and had a tendency to gel ~a~ilyO
22 ~XAMPLE 12 - Isobutylene~Isoprene Copolymer of Molecular Weight 1509000 (Numbe~ ~verage) Sulfonated to 23 ~
24 An emulsion w~s prepared according to the procedure given in Example 1, using 0~85% of high molecular weigh~ ~ul-26 ~obutyl (n~mber average 150,000) instead of 6~8% low molecu 27 lar weight sulfobutyl ~numbe~ average l5,000). I~ was con-28 taoted with a feed solution containing 2,400 ppm of NH4~.
29 The concentration of NH4+ was reduced to 21 ppm in 30 m~nut~s, ~ bu~ ~oon after this tim~ the entire mass gelled.

-~56531 2 The experiment given in Example 11 was repeated 3 with 0.40% high molecular weight sul~obutyl~ It was contacted 4 with a feed solution containing 2,080 ppm of NH4~ The con-centratlon of NH4~ was reduced to 145 ppm in 15 minutes~
6 However~ the entire mass gelled in 25 to 30 minutes.
7 ~
8 The experiment given in ~xample 11 was repeated g using 1 wt~ % sulfoEPT (number avera~e molecular weigh~
80,000; prepared by sul~onating ethylene-propylene-e~hyl 11 idenenorbornene to 1 mole % level). The conoentration of 12 NH~ was reduced ~rom 2,040 ppm to 12 ppm in 15 minutes.
13 After 60 minutes, however, the entire mass had emulsified l4 and the concentratlon of N~14~ had increased to 25,4 ppm.
These experiments indicate ~hat low molecular 16 weight sulfonic acid polymers are desir~ble in prep~ring ~7 compositions of the instan~ invention, e g~ molecular weights 18 of from 5,000 to 50~000O
19 Salts of Sulonated Po~
In order ~o study the efficacy as additives in 21 liquid membranes~ ~odium, ammonium~ and potassium salts were 22 prepared by neutrali~ation of low molecular weight (number 23 average molecular weight 15~000) isobutylenev-isoprene co~
24 polymer sulfonated to 1% and 2% level with corresponding bases. Attempts were m~de to prepare a 5% solution o~ ~hese 26 salts in Solvent Neutral*100. All of these salts were in-27 soluble at 25C, and 80CP 0f these, the potassium s lt o 28 polymer sulfonated to 2% level displayed the best solubility 29 behavior~ Its use in liquid membrane is described in Example 15, .

~L0S653~

2 A 5% solution of ~he potassium salt of sulfobutyl 3 (containing 2 mole % sulfonate groups) was prepared in Sol-4 vent Neutral*100 by heating to 85C and adding 0.5 cc of Bryj*30 of the Atlas Chemical Company, Wilmington, Delaware.
6 An emulsion was prepared from the solution by encapsulating 7 83 g, of 1% sulfurlc acid solution. This emulsion was con~
8 tacted with a feed containing 109 ppm NH4~. In 60 minutes 9 the N~ concentration was reduced to 46 ppm. However, the lo feed was very cloudyO This demon~trate~ ~hat these salts may 11 have very mRrginal utility as membrane additives in sour water l2 treatmen~.

l4 EXAMPLE 16 An emulsion was prepared from 100 g~ of a solution 16 of 6 8 g. of sulfobutyl in Solvent Neutra~ 100 as oil phase l7 and 83 g. of 16.9% polya~rylic acid (number a~erage molecular 8 weight 50,000, a product of Polyscienc~s, Inc ~ Warrington, 19 Pa.) as the internal p~aseO The emulsion was contacted with 740 g~ of an aqueous feed cont~ining 2,400 ppm o~ NH4~ at 85.
2l Within 30 minutes the concentr~tion of NH4+ wa~ reduced to 22 37O5 ppm and the emulsion w~ stable over the entire length 23 of the experiment ~90 mlnutes)O

The experiment given in Example 16 w~s repeated 26 with 28% aqueous glutaric acid as internal reagent The 27 temperature of operation was 8SCo nd the feed contained 28 2,020 ppm of NH4~ and 1~040 ppm of H2So After 29 minutes the 29 concentration of NH4+ was reduced to 78 ppm and H2S to less than 20 ppm.
* Trade Mark ~ 21 ` lOS6S3~

1 Wh8n phosphor~c acid or succlnic aclds are used in 2 the above example similar results are obtained~
3 EX~MPLE 18 4 An emulsion was prep~red from 6% by weight of low molecular weight sulfobutyl9 4 Wto % trioctylphosphinP oxide~
6 0.1 wt. % of trioctylamine9 and 90 wt. % of Solvent Neutral~
7 100 as membrane phase and 402 wt. % sodium hydroxide as the 8 ~qu~ous internal phase. The we~ght ratio of ex~ernal to in-9 tern~l phase was 1 1. 190 g. o~ this emulslon was contacted, with agitation~ with 800 mlO of ~eed~ containing 77 ppm of 11 chromium as sodium dichroma~e at pH 1060 Within 5 minutes, 12 the concentration of chromium in the ~eed was reduced to 13 less than 0.5 ppm.
14 The following examples demonst~ate the difficulties encountered in trying to use sulfonated polyst~rene, i.e D
16 aromatic sulfonatesO I~ is cle~r that these polymers do not 17 dissolve in the solvent systems which are desirably used and 18 if dissolved in a sui~able solvent axe precipitated upon the 19 addition of the desired solvents~

21 To 100 ml of Solvent Neutral~100 was added 2 g, of 22 polystyrene sulfonated to 0.81 mole % level. The mixture 23 was magnetically stirred or 24 hours and then filtered~ The 24 residue was washed with isoprop~nol~ It was dissolved in benzene and precipit ted by addition of propanol. The pre-26 cipitated solid was collected and ~ried, The weight of 27 polymer recovered was 2.0 g, whlch amoun~s to quantitative 28 reoovery~

A solution was prepared by dissolving 1J5 g of . ~ .

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polystyrene sulfonated to 0.81 mole % ~evel in 100 ml of 2 xy~ene~ To the solution, 100 mlO of Solven~ Neutral~100 was 3 added. The polymer precipitated as an oil. The supernatant 4 liquid was dacanted. The polymer was dissolved in 50 ml of benzene, reprecipitated by pouring into isopropyl alcohol, 6 eollected and driedThe weight of reeovered polymer was 7 1.1 g.
8 ~ PLE 21 q In this example, various emulsion~ are utilized in a tlquid membrane process for the trea~ment o sour water 11 to eompare the effect~veness of the emul ion formulat~on.
12 The additives w~re dis~olved at the wei~ht indicated in 13 Table I. In the instant example, 183 g. of an emulsion 14 where~n the e~terior phase comprised 55 volume % of the emul~
15 ~ion and the interior phase compri$ed 1% by weight sulfuric 16 acid ~n water, was contacted with an aqueou~ feed stream 17 containing various amou~ts of ammonia and ammonium ions~
18 The emulsion and the ~eed stream were contaoted in a vslume 19 ratio of 1:4~ This colttacting tool~ place under conditions 2a of agitation (200 RPM's) and a temperature of ~5C~ As 21 may be noted from the result~ ln Table I9 all the emulsions 22 were effective for the removal of ammonia. These specific 23 emulsion formulations have been found to be the most effec-24 tive formulations for mmonia remoYal in terms o transfer 25 through liquid membrane, l..eO the eæ~ernal phase of the 26 emulsion, into the lnterior phaseO

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'` - 24 . . , ~056531 The emulsion using ethylene~v~nyl ~cetate copolymer 2 sattled very q-lickly~ Thu9, upon stopping the stirrer the oil 3 phase~and aqueous feed ~eparated almo~t instantaneou~ly with-4 out leaving any of the haze which is produced by suspen~ion 5 of very fine droplets of oil in the feedO With the o~cher 6 additives, lengthy settling time ~o give cle~r feeds was 7 required.
8 ~~IPLE 22 9 In this experiment9 emulsions similar to those tested in ~xample 2l excep~ that a lO~ ~ul~uric acid interior 11 phase was utilized were compared for swell~ng r te. At thi~
l2 higher ooncentratlon of ~uluric aoid which would be co~mer-13 cially sign~fic~nt in a liquid membrane ~our water treating 14 process wherein the capacity of ~he emulsion for neu~raliza-tion of ammonia is important, the ethylene v~nyl aeetate eo-l6 polymer sho~ed superiority~ The next hes~ composition, ba~ed 17 on ~ulfonated butyl rubber, showed approximataly three times 18 as much swell while the sample based on Lubri~ol 3702 was 19 completely inoperative in that it gelled in 5 minutes.
The 3well wa~ measured in thi~ ex~ple by contacting 21 the ~mulsions with the ammonia con~aining feed ~tream in a 22 msnner s~mi~ar to Exam~le 21, At intervals the miYing was 23 discontinued and the height of the emulsion measured, after 24 5 mlnutes settlingO This is a direct indication of swelling properties of the emulsionO It is elear from the results 26 shown in Tabl~ II that the composition in the ~econd column 27 is ou~standi~g wi~h respect to lower ra~e of swelling. As 28 discu~sed ab~ve9 this proper~y is very ~raluable in liquid 29 membralle water treating processes~

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Claims (14)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A water-in-oil emulsion in which (A) the exterior oil phase comprises a sulfonated polymer and a solvent therefor, the sulfonated polymer having (i) a number average molecular weight of at least 1,000, (ii) a backbone which contains less than 25 mole % aromatic groups, and (iii) from 0.25 to 20 mole % sulfonic acld groups, the polymer being present in an amount from 0.05 to 40 wt. % of the exterior phase;
(B) the interior water phase contains an acid, alkali or other reagent.

2. An emulsion as claimed in claim 1 wherein the number average molecular weight of the sulfonated polymer is in the range 5,000 to 50,000.

3. An emulsion as claimed in claim 1 wherein the sul-fonated polymer has from 0.5 to 5 mole % sulfonic acid groups.

4. An emulsion as claimed in claim 1, 2 or 3 wherein said sulfonated polymer is a sulfonated butyl rubber polymer or a sulfonated ethylene propylene copolymer.

5. An emulsion as claimed in claim 3, wherein the sul-fonated polymer has from 1 to 4 mole % sulfonic acid groups.

6. An emulsion as claimed in claim 1, 2 or 3 wherein the said sulfonic acid groups are neutralized, to form a salt, with a C8 to C16 hydrocarbyl diamine or a C6 to C16 hydrocarbyl triamine.

7. An emulsion as claimed in claim 1, wherein the solvent for the said sulfonated polymer is an isoparaffinic distillate having an average carbon atom number of from 10 to 100.

8. An emulsion as claimed in claim 1, wherein the water phase contains phosphoric, sulfuric or hydrochloric acid.

9. An emulsion as claimed in claim 1, wherein the oil phase constitutes from 30 to 60 wt. % of the emulsion.

10. A process for removing the salt of a weak acid and a weak base from an aqueous solution, which comprises (a) contacting said solution with an emulsion as defined in claim 1, the exterior phase of the emulsion being immiscible with the solution but per-meable to the weak base, and the reagent in the interior phase being such that, when the weak base permeates the exterior phase, the weak base is converted by the reagent in the interior phase into a form to which the exterior phase is impermeable; and (b) re-moving said weak acid by passing an inert gas through said solution or subjecting the system to substmospheric pressure.

11. A process as claimed in claim 10, wherein said salt is ammonium sulfide.

12. A process as claimed in claim 11, wherein said inert gas is steam.

13. A process as claimed in any one of claims 10 to 12 wherein said reagent comprises an acid selected from phosphoric acid, sulfuric acid and hydrochloric acid.

14. A process as claimed in any one of claims 10, 11, or 12 wherein said removal is carried out at a temperature of from 25°C to 105°C and at a pressure of from 0.2 to 1.0 psig.