GB2166140A - Polymeric adsorbents for use in the purification of water and other chemicals - Google Patents

Abstract

A novel absorbent, for use in the removal of heavy metal cations from water and removal of organic coloring matter from sugar cane juice and antibiotic solutions (e.g. neomycin and gentamycin) has a microporous structure, a surface area of 35-45 m<2>/gm, a physical strength tested on Chatteliar tester of 800-900 gms., and a bulk density of 750-760 gms lit. It is prepared by subjecting cross-linked copolymer beads, e.g. styrene/divinyl benzene copolymer, to in situ chloromethylation in the presence of chloromethyl methylether followed by subjecting the chloromethylated copolymer so obtained to amination with a secondary amine with or without a monoamine.

Description

SPECIFICATION Novel adsorbents for use in the purification of water and other chemicals and a process for preparing same This invention relates to novel adsorbents for use in the purification of water and other chemicals.

It is already known to purify water by a series of ion exchange columns, but the removal of iron and other heavy metals such as Mn. and Zn. pose a problem. These cannot be removed by ion exchange techniques because if iron is deposited on a cation exchanger, it will affect the further function of the cation exchanger.

Natural water normally contains iron in the form of bicarbonates which are present in the water in the range of from 0. 1 to 20 ppm as iron. Water containing the higher ranges of iron cannot be treated directly in water treatment plants employing ion exchange resins. The reason for this is that the iron present in the water will foul the resin thereby progressively reducing its efficiency as an ion exchanger until a stage is reached when the resin can no longer function for the purpose for which it was intended. Any water treated in such a fouled system begins to exhibit a progressively higher content of iron, the harmful effects of which are obvious. Any product to which such water is then applied runs the danger of contamination.

It is, therefore, basically understood to be a prerequisite of water treatment that iron should be removed as much as possible from the water before treatment proper commences. Another reason for the removal of iron from water sources before such water is treated in a treatment plant lies in the fact that once ion exchange resins are fouled by the presence of iron, it is extremely difficult to elute the iron therefrom employing normal resin regeneration procedures.

Hitherto, it has been attempted to remove iron from water by processes of aeration and filtration. Alternative methods involve the use of chemicals such as lime and manganese dioxide which are added to the iron-containing water for the purpose of precipitating iron in the hydroxide form. Unfortunately, these methods apart from being inefficient, are also very expensive.

It is, therefore, an object of this invention to propose a novel adsorbent, which will effectively remove all the iron present in process water before it can be subject to usual ion exchange treatment.

It is another object of this invention to propose novel adsorbents which will have a microporous structure and can be easily regenerated.

It is yet another object of this invention to propose a novel adsorbent which will have satisfactory strength and can be re-used after regeneration.

It is a further object pf this invention to propose a novel process for the manufacture of these adsorbents, which will avoid the corrosive effect of chemicals used in the normal preparation of resins and which will pioduce a quality product having all the characteristics required.

It is still a further object of this invention to propose a novel method of removal of cations from process liquors by an adsorption technique using the novel adsorbents of this invention.

These and other objects of this invention will be apparent from the following paragraphs: So far as the applicants are aware, there is no prior art literature on the polymeric adosrbents for removal of cations by adsorption process. As abundant precaution it is clarified here that ion exchange method of removal of cations is quite distinct from adsorption method of removal of cations. In the former case, there is an exchange of ions between the matrix of the resin and the cations in the process liquor whereas in the latter case, cations in the process liquor merely get trapped on the adsorbent. So far as the applicants are aware, there is no polymeric adsorbent used or proposed or reported in literature for removal of cations such as iron, manganese and zinc.It is observed that the same adsorbent can be used for the removal of colouring matters or organic matters, from process liquors such as sugar cane juice and for treating antibiotic solutions such as gentamycin or neomycin.

The applicants are, therefore, the first to suggest and develop adsorbents for the above purposes and have successfully tested the same.

Thus according to this invention, there is provided an adsorbent for the removal of cations, which is characterised by a microporous structure, has surface area of 35-45 gms/cm2, has physical strength tested on Chatteliar tester as 800-900 gms., has bulk density of 750-760 gms/lit. and is of the aminated chloromethylated copolymer of a monoethylenically unsaturated monomer of the kind herein described, and a polyethylenically unsaturated monomer of the kind herein described.

More preferably the adsorbent is aminated chloromethylated copolymer wherein said polyethylenically unsaturated monomer is present in an amount of not more than 8% of the copolymer.

Still more preferably the adsorbent is aminated chloromethylated copolymer wherein secondary amino groups are attached to the resin matrix.

Further according to another feature of this invention, there is provided a process for the manufacture of novel adsorbents, which comprises subjecting copolymer beads of a monoethylenically unsaturated monomer of the kind herein described and a polyethylenically unsaturated monomer of the type herein described, to in situ chloromethylation in the presence of chlorome thyl methylether followed by subjecting the chloromethylated copolymer so obtained to a step of amination in presence of an aminating agent selected from a secondary amine with or without a monoamine.

According to a preferred feature, the chloromethylating agent is prepared by reacting a mixture of formaldehyde and methanol with chlorosulphonic acid and the copolymer beads are introduced into the said chloromethylmethylether thus produced.

In a preferred embodiment the copolymer contains not more than 8% by volume of said polyethylenically unsaturated monomer based on the total volume of the copolymer.

In another preferred embodiment, the chloromethylation is carried out in the presence of Friedel-Crafts catalysts selected from stannic chloride, zinc chloride, aluminium chloride, boron trifluoride, ferric chloride and the like to enhance the reaction rate.

The amount of these catalysts is preferably from 0.1% to 1.0% based on the total volume of the chloromethylation reactants.

It is advantageous to carry out the chloromethylation reaction at temperatures not exceeding 55"C, preferably between 20"C to 55"C for effective reaction, which can be carried out for 2 to 14 hours. Any excess reactant that is left can be removed by addition of water and filtration of the chloromethylated product.

In a preferred embodiment for every part by weight of formaldehyde we have used 1 to 1.3 parts by weight of methanol. We have found that for every part by weight of this mixture of methanol and formaldehyde we can use 3.5 to 4.1 parts by weight of chlorosulphonic acid.

There may be slight variations in these amounts depending upon the quality and the nature of these reagents. Best results have been obtained when equal parts by weight of methanol and formaldehyde are used and 4 parts by weight of this mixture of chlorosulphonic acid is used.

The amination is preferably carried out using any secondary amine more preferably dimethylamine. However, where cost considerations favour it, part of the secondary amine can be replaced by methylamine to the extent of up to 15%. We may thus use a secondary amine only or a mixture of a secondary amine and a methylamine. Most preferred are dimethylamine and methylamine, though other similar amines are useful. When the two amines are used, a partial pre-amination is carried on using methylamines followed by further amination using diamines. We have, however, found that to have effective bonding of the amino group in the matrix, of the chloromethylated product, it is preferable to open up the matrix prior to amination. Though this is not always essential, it is advantageous.This is done by allowing the matrix to swell, which is carried out by soaking the chloromethylated product in a swelling agent selected from benzene, xylene, methynol, dimethyl sulfoxide, 1,4 dioxane, methylethyl betone, dimethylformamide and mixtures thereof. The swelling can be carried out for as long a period as required and the object behind this is to make the matrix slightly soft and easily penetrable for aminating agent. There is no specific conditions or requirement for this swelling which may be also called as a pretreatment or preconditioning step. The material is soaked in swelling or pretreatment or preconditioning agent for a period of 30 minutes to 1 hour or slightly more, then removed from the agent and air dried before being subjected to amination.

This pretreatment step quickens the amination reaction and thus the chemical requirement will also be less. Though this pretreatment step can be dispensed with, it is not recommended so in view of the economics of reaction.

The amination properly can be carried out at atmospheric conditions, but favourable results have been found if this stage is carried out at pressures above atmospheric pressure in the range of 0.5 to 2.5 kg/cm2. The time of amination depends on the various conditions of reagents, their quality and process conditions. This may range from 1 hour to 15 hours.

We have found that the temperature of aminations is not very critical but a temperature in the region of 50"C is most ideal when a major part of amination takes place. The temperature may be raised up to 90"C and kept for a sufficient duration, if necessary to complete the amination.

After the amination, the excess reactants and solvent are distilled off.

The amination can also be carried out after storing the chloromethylated product for a period up to 6 to 8 weeks.

According to a still further feature of this invention, it has been surprisingly and quite unexpectedly discovered by us that the adsorbents so prepared are effective adsorbents or cations.

Such polymeric adsorbents of cations are unknown. This is primarily because the adsorbents prepared by the process of our invention are basic in nature. Evidence from trial runs have shown that the adsorbents function as effective adsorbing agents for iron, manganese and zinc.

The same adsorbents also can be used for adsorption of organic colouring matter from sugar solutions and for decolourisation of gentamycin or neomycin.

The adsorbents of the present invention work successfully with a feed water having an iron concentration of from 1 to 20 ppm as Fe. A preferred service flow rate for the feed water is in the range of 5 to 50 Bed volume/hr.

The contact between the iron-containing feed water and the adsorbent is usually effected in a vessel such as a column. The feed to the adsorbent is preferably a cylic one and the effluent issuing from the treatment vessel is continuously monitored for iron levels. When these levels exceed a predetermined minimum, the feed cycle is discontinued and the adsorbent is reactivated. This reactivation is preferably effected by eluting the adsorbent with acid and washing it with a solution of alkali of a level from 50 to 200 g/l. The concentration of acid and alkali vary from 1% to 40% w/v and the acid and alkali washes can be effected either in series or stepwise. Finally, the adsorbent bed is rinsed with water and backwashed. This backwashing causes the adsorbent beads to float in suspension and come to rest in a random setting so useful in procedures.

The preparation of the copolymer beads is not the subject matter of this invention because it is well known to prepare the copolymer beads.

However, briefly state, the preparations of the copolymer beads comprises adding to an aqueous medium a conventional stabilizer and a conventional electrolyte, agitating the mixture so formed to homogenity, adding to said homogeneous mixture a non-aqueous organic solvent or a non-ionic surfactant of the kind such as herein described, a free radical initiator of the kind such as herein described and a homogeneous monomer phase consisting of a monoethylenically unsaturated monomer of the kind such as herein described and a polyethylenically unsaturated monomer of the kind such as herein described, agitating the mass thus formed to homogeneity, subjecting the agitated mass to polymerisation in which said polyethylnically unsaturated monomer acts as crosslinking agent, removing the solvent or surfactant in any conventional manner and recovering in any known way the copolymer thus prepared in the form of porous beads or droplets.

All the reagents and other chemicals used in the copolymerisation process are known. Briefly stated: The monoethylenically unsaturated monomers which may be employed for the polymerisation are selected from methyl methacrylate, ethyl acrylate, acrylonitrile, styrene, vinyltoluene and the like.

The polyethynically unsaturated monomers which also act as crosslinking agents for the polymerisation are preferably divinyl pyridine, divinyl toluene, divinyl xylene, divinyl benzene, divinyl maleate, divinyl oxalate and the like.

Preferred examples of non-aqueous organic solvents or non-ionic surfactants include benzene, xylene, n-heptane, n-hexane, iso-octane, isobutyl alcohol and phenols. The amount of the solvent/surfactant present in the polymerisable mass can vary from 1% to 100% of the total monomer phase.

The stabilisers present in the polymerisation mixture may be selected from the group comprising polyvinyl alcohol, carboxymethyl cellulose, calcium phosphate, starch and gelatine.

The electrolyte for the polymerisation reaction is preferably a solution of sodium chloride or calcium chloride, more conveniently a 0.5% to 25% solution thereof.

Polymerisation initiators employed by the process of this invention are preferably of the peroxide type and may be selected from among lauryl peroxide, benzoyl peroxide, caproyl peroxide and methylethylketone peroxide.

The various aspects of the invention will now be more fully described with reference to the following Examples: I. Novel Adsorbents: Several samples of the adsorbents were prepared and their properties tested. The results are enumerated in Table 1 attached.

II. Method of preparation of the Novel Adsorbents: EXPERIMENTAL EXAMPLE 1.

PREPARA TION OF COPOLYMER BEADS.

An aqueous monomer phase was prepared having a monomer to water ratio of 0.9:1. The monomer contained 0.6 parts of styrene and divinyl benzene, out of which the divinyl benzene content is 12%, 0.4 parts of heptane and, as polymerisation initiator, 1% of benzoyl peroxide based on the total monomer content. The aqueous monomer phase thus prepared was incorporated into an aqueous medium comprising 1.2 parts of sodium chloride electrolyte and 0.3 parts of carboxymethyl cellulose as stabiliser. The two phases were agitated together until a single homogeneous phase was obtained which was then subjected to polymerization at a temperature of from 70"C to 85"C for a period of from 6 to 24 hours.After polymerisation was complete, the non-aqueous solvent entrapped in the copolymer was removed by distillation and the copolymer in the form of beads was recovered and dried at a temperature of from 50"C to 800C for a period of from 10 to 24 hours.

EXPERIMENTAL EXAMPLE 2 PREPARATION OF COPOLYMER BEADS.

An aqueous monomer phase was prepared having a monomer to water ratio of 1:1. The monomer contained 1 part of styrene and divinyl benzene, out of which the percentage of divinyl benzene is 6%, 0.48 parts of isobutyl alcohol and 1% based on the total monomer content of a polymerisation initiator. The aqueous monomer phase thus prepared was incorporated into an aqueous medium comprising 1.75 parts of calcium chloride electrolyte and 0.3 parts of carboxymethyl cellulose as stabiliser. Following agitation of the two phases to homogeneity, the homogenous mass was polymerised in accordance with the procedure of Experimental Example 1.

EXPERIMENTAL EXAMPLE 3.

PREPARATION OF COPOLYMER BEADS.

An aqueous monomer phase was prepared having a monomer to water ratio of 1:1. The monomer contained 1 part of styrene and divinyl pyridine, out of which the divinyl pyridine content is 18.5%, 0.5 parts of heptane, and, as polymerisation initiator, 1 part of benzoyl peroxide. The aqueous monomer phase thus prepared was incorporated into an aqueous medium comprising 1.95 parts of sodium chloride and 0.6 parts of carboxymethyl cellulose as stabiliser.

The two phases were agitated together to form a single homogeneous phase whereafter polymerisation of the homogeneous mass was effected in accordance with the procedure of Experimental Example 1.

ACTUAL PREPARATION EXAMPLE 1.

PREPARATION OF ADSORBENT BY CHLOROMETHYLATION AND AMINATION OF COPOLYMER BEADS.

A mixture of methanol and formaldehyde in the ratio of 1:1 was prepared and cooled to - 10"C. To the cooled mixture, 4 parts of chlorosulphonic acid were slowly added keeping the temperature at about 30"C to form in situ chloromethylmethyl ether.

To 230 gms of the chloromethylmethyl ether so formed, 90 gms of crosslinked polymeric material prepared in accordance with any of Experimental Examples 1 to 3 were introduced. 20 gms of ferric chloride were added and the reaction mixture was maintained at 33"C for 62 hours. The product was filtered, washed and soaked in methylamine for 21 hour and then air dried for 6 hours. The air dried chloromethylated product was added to and maintained for 2z hours in 270 gms of a mixture of dimethylamine and methylal. The temperature of the reaction was maintained at 50"C for 4 hours and then at 80"C for 6 hours. The solvent was distilled off after the reaction which was effected under a pressure of 1-2 kg/cm2.The resin product was then filtered, washed and converted to chloride form and finally converted to freebase form.

ACTUAL PREPARATION EXAMPLE 2.

PREPARATION OF ADSORBENT BY CHLOROMETHYLATION AND AMINATION OF COPOLYMER BEADS.

To 230 gms of chloromethylmethyl ether prepared according to Actual Preparation Example 1, 90 gms of crosslinked polymeric material prepared in accordance with any of Experimental Examples 1 to 3 where introduced. 20 gms of aluminium chloride were added and reaction mixture was maintained at 45"C for 8 hours. The product was filtered, washed and soaked in methylamine for 2 hours and then air dried for 6 hours. The air dried chloromethylated product was added to and maintained for 3z hours in 270 gms of a mixture of dimethylamine and benzene. The temperature of the reaction was maintained at 60"C for 4 hours and then at 80"C for 8 hours under a pressure of 2-3 kg/cm2. The solvent was distilled off after the reaction.

The resin product was then filtered, washed and converted to chloride form and finally converted to freebase form.

ACTUAL PREPARATION EXAMPLE 3.

PREPARATION OF ADSORBENT BY CHLOROMETHYLATION AND AMINATION OF COPOLYMER BEADS.

To 230 gms of chloromethylmethyl ether prepared according to Actual Preparation Example 1, 90 gms of crosslinked polymeric material prepared in accordance with any of Experimental Examples 1 to 3 were introduced. 20 gms of stannic chloride were added and the reaction mixture was maintained at 55"C for 8 hours. The product was filtered, washed, soaked in methylamine for 3 hours and then air dried for 6 hours. The air dried product was added to and maintained for 4 hours in 270 gms of a mixture of dimethylamine and xylene. The temperature of the reaction was maintained at 50"C for 4 hours and then at 85"C for 8 hours under a pressure of 2.5 kg/cm2. The solvent was distilled off after the reaction. The resin product was then filtered, washed and converted to chloride form and finally converted to free base form.

USE EXAMPLE 1 ADSORPTION OF IRON FROM WATER.

Through an adsorbent bed prepared in accordance with any of Actual Preparation Examples 1 to 3, a stream of iron-containing feed water was passed. The feed water possessed the following composition in all cases: 30 & 30 ppm as CaC03 Alkal i 36 ppm T.H. 46 ppm Silica 10 ppm Fe++ 15 ppm as Foe++ Effluents from the adsorbent beds were continuously monitored for iron levels. First few runs indicated no trace of iron in the exhaust water. This means that the adsorbent bed had still capacity to adsorb iron. After several runs, when the monitoring of the exhaust water indicated traces of iron, it was taken as an indication that adsorbent bed had exhausted its adsorption capacity.After the feed stream had been run for 10 hours, it was observed that the effluents contained 1 ppm Fe' indicating thereby that the adsorbent beds had become exhausted. The feed streams were discontinued and the beds were eluted and reactivated alternately with acid and alkali. After reactivation, the passage of feed water to the bed was recommenced.

USE EXAMPLE 2.

ADSORPTION OF IRON FROM WATER.

The procedure of Use Example 1 was repeated with a stream of iron-containing feed water having the following composition: FbtA 50 ppm as CaCO3 Alkali 16 ppm T.H.. 30 ppm Silica 20 ppm Fe 20 ppm as Be t-+ By continuously monitoring the effluent, it was found that the adsorbent bed became exhausted after 10 hours at which stage it was observed that the effluent contained 1 ppm Fe The feed stream was discontinued and the bed reactivated in accordance with the procedure of Use Example 1.

Use Examples Colour removal from sugar cane juice using the adsorbents of the invention.

We conducted several trial runs by passing sugar cane juice through adsorbent beds prepared according to the invention. This was conducted in a manner similar to Use Example 1. It was found that colour was removed from the feed solutions to a great extent. To make the properties of the adsorbents of this invention more clear regarding its capacity to remove colour, we produce in Table 2 several recorded details showing the feed analysis data and the treated stream analysis data. It will be observed that the colour removal is generally over 85% and reached as high as about 95%. The purity of the product stream also improved significantly. The ash content also significantly decreased. It was further found that the treated product stream was devoid of any hardness.

Use Examples.

Removal of colour from antibiotic solutions.

We have observed that the adsorbents of this invention are also highly useful in removing colouring bodies from antibiotic solutions when these solutions are treated in adsorbent beds of this invention. It has been found by us that most encouraging results are obtained when solutions of Neomycin and Gentamycin are treated using the adsorbents of this invention.

A few of the several advantages of this invention are the following: The chloromethylating agent employed for the step is invariably chloromethylmethyl ether. This ether is a highly corrosive substance and, what is even worse, it is a substance having carcinogenic side effects. It, therefore, constitutes both a safety and a health hazard and extreme care has to be taken to ensure that the ether is not unwittingly inhaled by personnel handling it.

Furthermore, there is the inherent problem arising from the ether's corrosity of having to effect frequent replacement of its corroded containers. Incidental to both these problems is the fact that because chloromethylmethyl ether constitutes a hazardous substance to work with; it becomes necessary to employ additional manpower to ensure that no damage is caused through careless handling.

The process of the present invention by its in situ formation of chloromethylmethyl ether effectively avoids the health and safety hazards posed by this highly corrosive, carcinogenic substance in that either does not have to be handled as a separate, independent component in the reaction. This brings the added advantage of having to employ less reactors and reaction stages and a corresponding reduction in manpower. There is less corrosion of reactor vessel and the in situ production of chloromethylmethyl ether enables better employment of the individual reactants.

Another advantage and saving which the in situ production of chloromethylmethyl ether affords is that, unlike prior art methods, there is no necessity to soak the crosslinked polymeric material in a swelling agent, such as ethylene dichloride or chloroform, prior to subjecting the polymeric material to chloromethylation.

By effecting amination of the chloromethylated polymer matrix at high temperatures and at pressures above atmospheric pressure, it is possible more efficiently to introduce amines into the polymer matrix. The loss of amines during amination is kept to a minimum and any unreacted amines can be recovered simultaneously with the amination reaction solvent. Under former processes, unreacted amines had to be recovered in a subsequent operation.

NOVEL ADSORBENTS - TABLE 1.

EXP. Monomers Used Chloro Aminating P R O D U C T P R O P E R T I E S No. Methylating Agents Agent 1 2 Surface Mech. Osmotic Moist. Bulk Sp.

Fe Colour Area Strength Strength Content Density Gr. Rem.

Rem.

m/gm gms on for 500 % gms/ gms/ Chattel- fro Cycles lit lit iar Tes- m as ter sug Fe ar cane juice % 1. Stry- Divinyl Chloro- Dimethyl 20-25 400 Good 40-50 800 1.08 2.50 50 ene Benzene sulphon- Amine and ic Acid. Methylol 2. Styr- Divinyl Chloro- Dimethyl 35-55 950- 60-65 750- 1.04 7.00 80 Very ene Benezene sulphonic Amine and 760 90 1000 Good acid. Benzene 3. Styr- Divinyl Chloro- Dimethyl 15-20 250 Poor 45-50 810 1.085 1.50 35 ene. Pyridine sulph- Amine and onic Xylene.

acid.

TABLE 2 COLOR REMOVAL DATA USING SUGAR CANE JUICE

F E S D A O L S s S F E 5 D AlJ A LY 51S i T- 4 , lleums '", C,, !X. > ,X t r j,ra zC3d.oo 5986 1670'29 51'46 Bq-'iS 84-S5 .~ - ~ ~~~ ~ ~ - 2 ?-iX ~ ~ 3042-40 IS46 oo 39-31 ~ ~ ~ 3 476 ~ ~ ~ ,~ 1946'oo ,39'31 s{s7;fc;} .

3 7'34 286.78 !3's2-oa ;3192too 2197 75 31-15 ~ ~ a5553i . 4 71+ 218l80 3970 339Tso7as 53o 6-I6 5 640 224Z42 a3960 522-38 140s 56 6027 84-92 Is ~ -- ~ . ~~ t 6 3241-BY 1406-56 3241 87 14c 67-67 -4Q3210-5670 . , ~~ - 25? - {w 63'70 ~~ ~~~ ~~ ~~ ~~ ~ j . .

7 -- I, - --- - {; -1- - . ~ '~~~~ ------- ---- - ---- ~~ ~~ 8 '7.03 oo 1 5't85 ---- /3341'L4'1J18.65 ---- --- 86 15 ----t-- 16-77 252I4 808 4354164 494-47 Sus'2 8571 420 05not 62 > 44420 SOS r655S (84-ll s-ygz - - rslg 241r,o 662 374O. 2021-93 94 e i 1 S I ~ &verbar; ~ ~~~ f2S-72 254520 754 381O4o 1670'30 5650 I 1- ------------- 43 5.'10 2142'20 962 J79oSZ 1890.06.5013 tP { . ~~.~ ~~+~ ~ I '5-53 2242-20 1091 3591-00 1742 00 51-4 ~ ~ - - --- ------ -- --~l - - I ~--- ----- t- ' r- Ir. 45 22B2-60 983 3541-15 158238 55.31 16 5-52 :2P92-60 1293 13 > I4o656 i iS3t12t81'60 1293 3321'32 :1906'56 :.i;s-7ot2282ooIe9l 13z4S9 1131865159-32183'7 ! > Mti '0'4979 i - :----t--t -t | - -t -- 69 - t t ~ 1 5 S8; 2242 II 3042'39/ 3 Is I5i%;241-2o --------- i .- 1 ... 4 1. T.H. = TOTAL , HARDNESS 2. ICUMSA = INTERNATIONAL COMMISSION FOR UNIFORM METHOD OF SUGAR ANALYSIS 3. EMA = EQUIVALENT MINERAL ACIDITY 4. R.S. = RESIDUAL SUGAR 5. BV/HR. = BED VOLUME/HOUR 6.T.V. = TOTAL VOLUME TABLE 2 (CONTINUED)

7 TReATED STteAt ANAI SSl S t---777---t-- t RX AA T P il445 Bt IN ! Ifl lu ------- I . . try - Phi iT.. Cl- CoLO - DRIN I^si , BV/iHr. TV sPCrT1 & !sN c ... - 4~ icu~~%m;m I ~ t , ~ I jSV!11 -4 LTS. Ilteseocoa: 343 uL 32'9j5s 32-26 by ?z 53I SO. 29 1'0280 00325 41 157 .6-39 4 ulr -~~~~~ --. .2.112.34- i r-8516 ,.26'37 1 i'9o29 .0-8516 o-o3 ~,, 121 , i ~ ~ I :3-062 7'50 NIL 26'37 908 ,a6 i 600 :3-062 ;g10 7-30 rOIL 17 s 908 j9O19 |o asl6 ----.4------ 1 94 is i9029 " " -" 7- 38'15 NIL 2L'17 1 ≈ i ~ ~ ~ I z; .2- 81f} - .6.70 ~ ----t t . t~ .000142.49 I - - - c f ~ y ~ ~ ~ ~ -- -- 7.22 i I - --t- 2.110 NIL NIL 17 58 1 -- | I-------. 12.710 710 4 36'88 26.37: 7..Th.iNffiLW 76s NIL 17 ss 69 ~~~. . ~~ j t ~~ +. ~ ~ ~ + a t 768 nlL ,7S8j 59 I i 1 58) 12. 800 ""1" , '169 N, 2,.?/ 93 -1 c92 2'4D ' 1 56 go 1 7'30 Iric 17-58 lr2. 93 6'2'9 3740 121 jIL 175i81 802 i ~ 69 7-62 NIL '-.- - - 2 5-81 38-76 lffis8} t~t t T + t | t , \ j t '7'0 NIL 17 58 112, ~ 9} , 5 '-----t I i : Je-15 7-t5 NIL 99-T - 7---'!73a 3-3 7- rilL 17-58 102 -:89 5 65 73 ---- -,---- - -1 ~ . .! . - -- r {;.72 - -- I - 38. 91 5-89 2'7O04oft -6' - - 2-666, 38-15 7-47 NIL - - - : loI270Ol 6-61'NIL- ! 160 - 3%7 - i - - - - s4 ! 6 1o | 36'95 6 62 jNIL, 17-5S I ~ I . . 2,~ t - . 36 ffiA2 1ILfD;.q..'.I4. ,2-8So 9S i2 NIL 142 ----- I jo'95%e'o283,7o0;63 ,,94 j - -- r ;9o-34;o-%l92o-o237'.7-93 54 , 95 91 S-94' 7-00 - 63 94 la s-49F I I

Claims (22)

1. An adsorbent for the removal of cations, which is characterised by a microporous structure, has surface area of 35-45 gms/cm2, has physical strength tested on Chatteliar tester as 800-900 gms, has bulk density of 750-760 gms/lit and is of the aminated chloromethylated copolymer of a monoethylenically unsaturated monomer of the kind herein described, and a polyethylenically unsaturated monomer of the kind herein described.

2. An adsorbent as claimed in Claim 1 where adsorbent is aminated chloromethylated copolymer wherein said polyethylenically unsaturated monomer is present in an amount of not more than 8% of the copolymer.

3. An adsorbent as claimed in Claim 2 wherein, the adsorbent is aminated chloromethylated copolymer wherein secondary amino groups are attached to the resin matrix.

4. A process for preparing an adsorbent as claimed in Claim 1 which comprises subjecting copolymer beads of a monoethylenically unsaturated monomer of the kind herein described and a polyethylenically unsaturated monomer of the type herein described, to in situ chloromethylation in the presence of chloromethyl methylether followed by subjecting the chloromethylated copolymer so obtained to a step of amination in presence of an aminating agent selected from a secondary amine with or without a monoamine.

5. A process as claimed in Claim 4 wherein the chloromethylating agent is prepared by reacting a mixture of formaldehyde and methanol with chlorosulphonic acid and the copolymer beads are introduced into the said chloromethylmethylether thus produced.

6. A process as claimed in Claim 4 and 5 wherein the copolymer contains not more than 8% by volume of said polyethylenically unsaturated monomer based on the total volume of the copolymer.

7. A process as claimed in Claims 4 to 6 wherein the chloromethylation is carried out in the presence of Friedel-Crafts catalysts selected from stannic chloride, zinc chloride, aluminium chloride, boron trifluoride, ferric chloride and the like to enhance the reaction rate.

8. A process as claimed in Claim 7 wherein the amount of these catalysts is preferably from 0.1% to 1.0% based on the total volume of the chloromethylation reactants.

9. A process as claimed in any of the procedures claimed, wherein the chloromethylation reaction is carried out at temperatures not exceeding 55"C, preferably in the range of 20"C to 55"C for about 2 to 14 hours.

10. A process as claimed in Claims 4 to 9, wherein for every part by weight of formaldehyde is used 1 to 1.3 parts by weight of methanol.

11. A process as claimed in Claims 4 to 10, wherein for every part by weight of mixture of formaldehyde and methanol 3.5 to 4.1 parts by weight of chloro sulphonic acid is used.

12. A process as claimed in Claims 10 and 11, wherein equal parts by weight of methanol and formaldehyde are used and 4 parts by weight of chlorosulphonic acid are used for every part by weight of the mixture of formaldehyde and methanol.

13. A process claimed in Claims 4 to 12, wherein the amination is preferably carried out using any secondary amine more preferably dimethylamine.

14. A process as claimed in Claim 13, wherein the secondary amine is used with or without a monoamine.

15. A process as claimed in Claim 14, wherein the amination is carried out using a mixture of 85% secondary amine and 15% mono amine.

16. A method as claimed in Claim 15 wherein the secondary amine is dimethylamine and the monoamine is methyl amine.

17. A method as claimed in Claims 14 to 16, wherein the monoamine is used first for partial amination of the product before using the secondary amine.

18. A process as claimed in Claim 13, wherein preferably before amination the product is subject to swelling in a swelling agent selected from benzene, xylene, methynol, dimethyl sulfoxide, 1,4 dioxane, methylethyl betone, dimethylformamide and mixtures thereof.

19. A process as claimed in Claim 13, wherein the amination is carried out at atmospheric pressure or at pressures in the range of 0.5 to 10 kg/cm2, preferably at temperatures around 50"C or more.

20. A process for preparing an adsorbent resin substantially as herein described with reference to example.

21. An adsorbent resin prepared by the processes claimed in Claims 4 to 19 or 20.

22. A method for the removal of cations like iron, manganese, zinc or organic colouring matter from sugar solution and antibiotic solutions like Gentamycin and Neomycin from process liquors, which comprises passing said process liquor through a bed of adsorbent, as claimed in Claims 1, 2 or 3 or Claim 21.