DE1517519A1 - Process for the bromination of water and aqueous solutions - Google Patents

Description

Patent Attorneys Dr.-lng. K '^; ~ ^{f S} SCIKE _k ", _w " | 1Θ66)

DipW ^ i · "1- ^ IAA TP I.

β Munich 27, rio4izonauerSfr. 2

₁₃₉₇ I ^

ibe Dow Chemical Ooinpany, Midland, Hichigan / V.St.A.

Process for the bromination of water and aqueous solutions

The invention relates to a method for treating Water and aqueous solutions with bromine to be located in it Fight microorganisms.

The use of chlorine and bromine to disinfect and sterilize water serves many different purposes Purposes and is known. Urban viaduct chlorination is standard practice in the United States States and others too! Have been changing for many years. It is now well known that on equimolar Ba, sis bromine as effective as chlorine in fighting bacteria, algae, slime and other microorganisms is in water supply lines. ! Indeed, an excellent Fighting many bacteria in water can be achieved when as low as 0.1 ppm Bromine is used.

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In the case of heavily contaminated water, a strong initial Impact treatment with 3 to 30 ppm bromine may be beneficial to kill the contaminating microorganisms, whereupon a remaining bromine concentration of 0.1 to 1.0 pin in general is effective in maintaining safe water. The extent of shock treatment is of course of the nature of the contaminating microorganisms dependent. To treat water for human consumption is a shock treatment with 3 to 5 ppm bromine generally sufficient to avoid the undesired Kill bacteria. However, a “heavy contamination with slime and algae, as in the case of the in industrial cooling towers e.g. water used can occur, often a shock treatment with 10 to 30 ppm bromine. For example, while 2 ppm bromine significantly inhibits the growth of Chlorella, a common strain of algae, 10 ppm bromine is one pronounced inhibition and 10 to 20 ppm required for complete kill.

In addition to its effectiveness as an antimicrobial agent, bromine shows when used to clean water lines Other advantages. Because of its lower volatility, the desired remaining level of halogen can be achieved retained in the treated water with bromine more easily than with chlorine, especially under turbulent conditions Flow and stirring. Furthermore, bromine results in little or no undesirable taste or odor in the treated water as bromine continues to drop

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_ 3 - ·

Destruction of suspended or dissolved organic matter, which often cause an undesirable color and odor, acts, eats it especially for use as a treatment agent suitable for health purposes in swimming pools, whereby completely clear, colorless and odorless water is extremely desirable int.

Thus, the treatment of water with bromine is advantageous to produce large volumes of water suitable as potable city water and for many other technical, industrial and domestic uses. In particular, bromine is extremely favorable for YerwCiIdUiIf ₁ ; as a treatment agent for ijc / iwimrnbeeJieii, industrial oil towers and other circulating water systems, since a very low concentration of bromine both destroys the bacteria initially present and helps to maintain hygienic conditions despite repeated renewed contamination.

Due to the extremely corrosive properties of elemental However, bromine poses serious dangers when used. The danger of handling liquid. Has bromine make its use as a sanitary treatment inadvisable, especially in smaller systems, where cumbersome equipment for handling liquid bromine is not applicable. In some cases the use was of liquid bromine prohibited by prohibition.

BATH ORIGINAL

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Therefore there is a need for a safe and practical applicable method by which bromine is stored, handled and added to water even by inexperienced persons can be. Such a process requires a form of bromine that is easy and safe to manufacture is stable during storage and shipping, which in the event of accidental skin contact is not causes serious burns and still contains elemental bromine, as required for sanitary releases.

It has now been found, and this forms the basis of the present invention, that a brominated anion consists of tauachhar ζ, which contains polybromide anions, bromine slowly releases it into water and aqueous solutions with which it comes into contact. Thus, the brominated anion exchange resin is an 'outside * convenient, effective and safe means of Handling of elemental bromine for use in treating water and aqueous solutions to control Microorganisms. According to the present invention, water or aqueous solutions can be easily brominated by at least part of it in contact with a brominated Anion exchange resin is brought and the so brominated solution is intimately mixed with the remaining unbrominated portion. The brominated resin used contains polybromide ions in bond with the ion exchange parts of the resin. Preferably, the anion exchange resin used is composed of a water-insoluble polymer to which quaternary ammonium groups are chemically bound. q aa qcq / 1101

The brominated anionic resin according to the invention is used essentially as a source of energy from which elemental bromine can be removed to the extent necessary to combat bacteria, algae, slime and other microorganisms to "effect or maintain" in an amount of water. Such Resins "are not only extremely valuable and inexpensive Properties with regard to both the bromolacs fcung and also the elution properties, but are also chemical for long periods of time under normal storage conditions stable and can be safely manufactured, stored and dispatched without a reduction in quality. Even though it is of course not favorable, cause momentary occasional contact of the polybromide resins even with wet ones Skin no burns. In addition, that obtained by contacting the polybromide resin with water is aqueous solution sufficiently diluted so that there are no burns on contact with the skin.

The invention described herein thus relates to an improved method for treating water with bromine. In a preferred Embodiment of the invention consists of the improved Process in that 1.) an anion exchange resin in polybromide form is brought into contact with water, whereby bromine from the polybromide resin to form an aqueous solution with a content of 10 to 10,000 ppm bromine is removed ^ and 2.) a sufficient amount of this aqueous bromine solution is mixed with the water to be treated so that 3I have a concentration in the range from about 0.02 to

30.0 ppm bromine is set.

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The adsorption of elemental bromine by an anion exchange resin was reported in "Ohem. And Ind.", Page 1238, 1957, by Avesbon and Everest, who found, when treating an anion exchange resin with an aqueous solution containing elemental bromine, that the polybromide anion Br "", v / orin η means the numbers 3, 5 or 7, which becomes the predominant ion type in the resin phase. In the case of a quaternary ammonium resin and an excess of bromine, the resin was converted into the Br ₇ "-jorm by adsorption of 3 hols of bromine per resin equivalent.

In practicing the present invention are commercially available anion exchange resins, which by implementation of a chloromethylated styrene-divinylbenzene resin with a corresponding organic amine were prepared, as bromine

particularly
carrier / suitable.

Since the working conditions of a polybromide anion exchange resin column similar to those of conventional ion exchange resin columns common resins and common working methods are generally considered in view of such factors as the extent of the Resin crosslinking, grain size and flow velocities, satisfactory.

A particularly effective method of making a suitable one Polybromide resin is that a practically saturated Solution of bromine in aqueous sodium bromide by a. Bed of anion exchange resin is slowly added. At the-

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- π -

This method of operation was adsorbed by a commercially available resin a capacity, based on dry weight, of 3.50 hiII equivalents per g in the Cl "~ -iOrai, quickly 3 KoI bromine per equivalent of the chlorine originally on the resin. The resulting polybromide resin contained approximately 48.6% bromine by weight in the wet form. This adsorbed bromine was in an analysis quantitatively removed by treatment with a sodium bisulfite solution, oiiin an attempt to further remove the resin Loading under more severe conditions resulted in bromination of the resin matrix, while the elutable bromine content remained at about 3 moles per resin equivalent.

Palis the polybromide resin is dried or large volume Exposure to air may cause some of the adsorbed bromine to be lost. However, if it is in a sealed container made of a bromine-resistant material such as polyvinyl chloride, the resin is stable for long periods of time.

At usual flow rates of 4 to 41 ml / cm /

Minute (1 to 10 gpm / ft.) Of the cross-sectional area of the resin bed, the elution of the bromine with water is practically independent of the contact method used. The equilibrium setting between the bromine adsorbed on the anion resin and that contained in the aqueous phase is reached quickly. At room temperature, the aqueous phase in contact with a quaternary ammonium resin in fully charged Br ₇ "-] form contains about 7000 ppm of bromine. Elution studies with a column of this resin showed that the bromine concentration

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in the eluent dropped to about .1300 ppm after a volume of water corresponding to 100 bed volumes had passed through the column. After 1400 bed volumes were passed through, the bromine concentration in the eluent dropped to about 50 ppm and about 95 ^c / ° of the adsorbed bromine had been removed. Further elution reduced the residual bromine content of the resin and the eluted bromine concentration then dropped to 10 ppm and below.

The temperature has a significant influence on the bromine equilibrium between resin and aqueous phase. For example, water in contact with an approximately equivalent amount of the polybromide resin, which contained 2.14 moles of bromine per equivalent of resin, had an equilibrium concentration of about 13,800 ppm of bromine at 55 ^° C. and of 4270 ppm at

A regeneration of the exhausted or partially exhausted Polybromide resin can be easily obtained by treatment with a bromine solution, as described above, if desired will reach.

A higher elution concentration of bromine is necessary for a shock treatment where 10 to 30 ppm in the treated Water are required than they are required to maintain a residual bromine content of 0.02 to 1.0 ppm bromine is. The frequency of regeneration depends on the requirements of the particular system.

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The eluting solution containing bromine can be measured and grounded added to a further amount of water in the necessary hatred to give or maintain the desired concentration of bromine in the treated water. Usual analytical methods can be used to determine the bromine concentrations and to regulate the treatment process can be applied. In the event of a profit, an automatic Equipment can be applied to continuously display the bromine concentration of the treated water and in the necessary hatred, a more concentrated bromeluate add to keep the bromine concentration within the desired limits. Such a regulation is special beneficial in a circulatory system, such as is commonly used in swimming pools, where part of the flow through the system flowing water can be separated by suitable measures so that it goes through a polybromide resin column and bromine is eluted therefrom.

Example 1 - Polybromide Resins

A. A portion of a common quaternary ammonium-styrene-8 Jt-divinylbenBOl anion exchange resin, which consists of spherical particles with average diameters of 0.9 to 0.3 mm with a dry weight capacity of 3.5 milli

_ one

equivalent en / g 01 "-I ¹ Oi ¹ IiI was placed in a glass column with an internal diameter of 2.54 cm and charged with bromine, for which purpose an excess of an aqueous solution containing about 35% by weight of bromine and 17% by weight ^! Contained sodium bromide,

ORIGINAL INSPECTED

dur.cli the column was given. After loading is complete the excess bromine solution was drawn off from the column and the Polybromidhars with a small henge of water flushed. A sample of the harvested moist polybromide resin contained 48.6% bromine by weight. The adsorbed bromine was quantitatively removed from a portion of the treated resin by an analytical treatment with a sodium sulfite solution removed. The bromine removed as bromide corresponded to a theoretical capacity of 3 1-iol Brou / liarz equivalent of the anion exchange capacity.

B. In an attempt to further load the resin, the concentrated aqueous bromine solution was heated to 50 ^ 3 and circulated through the resin bed for a few hours. The resin then turned some at room temperature Left in contact with the bromine solution for days. The moist resin obtained contained a total of 64.9% by weight Bromine. However, after one treatment of this resin - ,,;. with excess sodium sulfite solution 16.4% by weight Bromine back, which indicates bromination of the resin matrix. The elutable bromine corresponded to about 3 moles of bromine per equivalent the initial resin capacity.

G. Similarly, the Polybromidformen other styrene-divinylbenzene resins which contain 1 to 16 i »divinylbenzene were nergestellt. A polyvinylpyridine quaternary resin according to US Pat. No. 2,801 has also been used

; ^ ■ -,: .. ./,^r ORIGIN ¹ ""

- .- ■ · ■ · '·· * ίί.' · Ί ... fet ■

and a commercially available quaternized Polyäthoscypoly- aminhars converted into corresponding polybromide forms. Although the bromine capacities of these resins in terms of the proportion of their initial anion exchange capacities were the same, these latter two resins were less stable than the preferred ammonium-styrene-divinylbenzene quaternary resins.

2 - Elution Characteristics

Using a 2.54 cm internal diameter column constructed with the polybromide form of that described in Example 1A When the resin was filled, a series of elution attempts were made carried out at room temperature. There was no noticeable change the elution properties at flow rate winds

p Ο

speeds from 20 to 41 ml / cm per minute (5 to 10 gpm / ft.), a bed depth of 40.7 and 91.4 cm and a Strora upward guide or downstream duct found. In Table I are values from a typical elution using a moist resin initially containing 4.5% bromine by weight, summarized.

Table I. Elution properties

Bed volume of the
Eluting agent 10 50 100 300 600 1400 ^Br 2 in the eluate, ppm 7000 3000 1300 350 150 50 Total elution
tes Br ₂ 9.9 # 30.0? £ 55.2 ^ 74.8 & 85.5 # 95.4! Example 3 - swimming pool unit

A small resin column of 10 cm in diameter and 40.7 cm in height, containing 3.7 l of the resin according to Example 1 in the polybromide form

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was filled and had about 2, '*>'; ■ kr bromine., was built into the liiickctroii.ilung of a l'iland high swimming pool of 75 "/ m" clngc. By means of suitable valves, part of the circulating water could be branched off after the piltration unit, but it went through the Hara column, whereby a rope of the adsorbed bromine was eluted for addition to the main circulation stream.

The initial flow of the circulating water through the ilars column is manually goregulated to maintain a bromine concentration in the. ^: iauptmen <-; e keep the basin between et v / a 0.7 and 1.2 ppm * /.!! Finally, an automatic instrument is installed; to regulate a solenoid valve in the line to the rolybronid column, whereby part of the Kreia-Ia * ..; f, ij-troraee from time to time by the JOlybroraidharzkolorme

if
branched off vmrde, -wtre it was necessary to maintain the desired brook concentration. For example, on a poor ilacii day the llarz column was switched on with a cycle of about 10 minutes and then switched off for about 20 minutes. After every installation

During the period, the bromine concentration in the basin began during one-bottom

ger minutes to soar on / of the pool mixing properties before it slowly fell off when the bromine was used up. Nevertheless, the concentration in the operator could easily be between et v / a hold 0, c0 and 1.05 ppm. While the watch was the bromine consumption practically 0.

30 9 8 50/1101 BAD ORIGINAL

V'ilirencL a long experimental period with the Polybroiniduarskoloune The pool showed no signs of algae growth and was kept in virtually sterile condition held because a bacterial plate cooling of less than 0.1 per cm was obtained.

6AD ORIGINAL 909850/1 101

Claims (3)

Claims 1.) Process for irradiating water or aqueous solutions to inhibit the axis of microorganisms, thereby marked as ίο at least enc a ϊβίΐ i & s V / assers or the solution in a solution with a brominated anion 9ne.uatausciiiaarz is brought and who üromiert this yiieise solution is intimately mixed with the remaining unrosed water or the remaining unbrominated part of the solution. 2.) Method according to claim 1, characterized in that the brominated anion exchange resin in polybromide anions Contains binding with ion exchange parts of the resin. 3.) The method according to claim 1 or 2, characterized in that an Ani onenaus tauo chliar ζ, which consists of a water-insoluble Polymers, to which quaternary ammonium groups are chemically bound, is used. 909850/110 1 6AD