Patent GB-768665-A (GB)
Title: Treatment of aqueous liquors
IPC: B01D15/04
Filed: 1952-06-09
Abstract: The following compounds, inter alia, are employed for the treatment of aqueous liquors containing suspended particles (see Groups I and III): styrene-maleic acid copolymer b -dimethylaminoethyl half ester, prepared by warming a styrene-maleic acid copolymer with excess b -dimethylaminoethanol; polyvinylpyridine methyl p-toluenesulphonate quaternary salt by treating polyvinylpyridine with methyl p-toluenesulphonate; polyvinylpyridine butyl bromide quaternary by preparing poly-4-vinyl pyridine by polymerizing in toluene with benzoyl peroxide catalyst and treatment with butyl bromide; vinyl pyridine-acrylonitrile copolymer hydrosulphate by emulsion polymerization of 2-vinyl pyridine and acrylonitrile, using soap as emulsifying agent, and dissolution after isolation in sulphuric acid; the methyl p-toluene sulphonate quaternary salt of the above polymer may be similarly prepared; polyvinyl chloracetate pyridinium salt by mass polymerization in the presence of benzoyl peroxide to produce polyvinylchloracetate which was dissolved in pyridine; the trimethylamine quaternary may be similarly prepared; polydimethylaminoethyl methacrylate hydrosulphate by polymerizing b -dimethylaminoethyl methacrylate in sulphuric acid with potassium persulphate catalyst; polydimethylaminoethyl methacrylate methyl toluene sulphonate quaternary by first preparing poly-b -dimethylaminoethyl methacrylate by ester interchange between polymethyl methacrylate and dimethylaminoethanol in the presence of benzene sulphonic acid catalyst, and then treating the polymer in dimethylformamide solution with methyl-p-toluene sulphonate. Specification 723,869, [Group VIII], is referred to.  Reference has been directed by the Comptroller to Specification 723,868.ALSO:Aqueous liquors containing suspended negatively charged particles which are in a flocculated condition due to the presence of inorganic cations in a quantity sufficient to neutralize the charges of the particles, are treated with a cationic polyelectrolyte in an amount not more than 0.1 per cent by weight of the liquor treated so that the particles become aggregated and separable from the liquors. The cationic polyelectrolytes are water soluble linear polymers or copolymers which form cations containing penta-valent nitrogen atoms when dissolved in water. The inorganic cations may be provided by inorganic salts naturally occurring in the liquors to be treated or deliberately added.  Alternatively the cationic polyelectrolyte can be used both to convert the negatively charged particles into a flocculated condition and then to aggregate the flocculated particles without inorganic electrolytes being present.  The liquors treated may be waters of natural or artificial origin such as trade effluents or waters from fish ponds or lakes and the process may be applied to the recovery and treatment of clays, the preparation of pigments and the production of paper and textiles. Suitable polyelectrolytes are salts with acids of polymers or copolymers containing amino groups, for instance amine salts obtained by hydrochloric or acetic acids; amine salts of a homopolymer of a dialkylaminoalkyl ester of an a  b ethylenically unsaturated aliphatic carboxylic acid such as acrylic or methacrylic acid, or of a copolymer of a dialkylaminoalkyl ester of an a  b  ethylenically unsaturated aliphatic carboxylic acid such as acrylic, methacrylic or maleic acid with an olefinic compound copolymerizable therewith, for example styrene.  Other suitable amine salts are salts of polymers or copolymers containing pyridine nuclei or a copolymer of vinlypyridine with an olefinic compound such as acrylonitrile.  The polyelectrolyte can also be a quaternary ammonium salt for example formed by the interaction of an aliphatic or heterocylcic tertiary amine with a homopolymer of a vinyl ester of a saturated halogenated aliphatic monocarboxylic acid such as polyvinyl chloroacetate. Polyacrylamide, polymethacrylamide or an acrylamide-acrylonitrile copolymer may be used.  Examples of polyelectrolytes, the preparation of which is given (see Group IV(b)) are polyacrylamide, polydimethylaminoethyl methacrylate, acrylamide-acrylonitrile copolymer, methacrylic acid (35 per cent)-dimethylaminoethyl methacrylate (65 per cent) copolymer, styrene-maleic acid copolymer-b  dimethylaminoethyl half-ester, polyvinylpyridine hydrochloride, polyvinylpyridine methyl-para-toluenesulphonate quaternary salt, polyvinylpyridine hydrosulphate, polyvinylpyridine butyl bromide quaternary salt, vinylpyridine-acrylonitrile copolymer hydrosulphate, vinylpyridine-acrylonitrile copolymer methyl-para-toluenesulphonate quaternary salt, polyvinyl chloroacetate pyridinium salt, polyvinyl chloroacetate trimethylamine quaternary salt, polydimethylaminoethyl methacrylate hydrosulphate, polydimethylaminoethyl methacrylate-methyl toluenesulphonate, quaternary salt.  According to examples (1) a turbid river water having a pH of 8.05 containing suspended silt particles and sufficient inorganic cations to flocculate the silt particles was treated with 0.1 gram of polyacrylamide per 3 litres of water followed by 0.13 grams of aluminium sulphate in aqueous solution.  The liquid was stirred for twenty minutes and on standing the flocculated particles became aggregated and these with a certain amount of aluminium hydroxide precipitate settled out rapidly.  (2) A river water as in example (1) was treated with ferric sulphate followed by the addition of an aqueous solution of polyacrylamide to aggregate and settle the particles.  (3) To 100 grams of silt loam suspended in 1 litre of tap water containing sufficient cations to flocculate the negatively charged silt particles was added 0.1 grams of dissolved polyacrylamide whereupon the flocculated particles became aggregated and settled rapidly, the settling rate not being impaired by the presence of sodium chloride, ferric chloride or aluminium sulphate. (4) To 500 ml. of a 1 per cent suspension of finely divided wood pulp in water was added 0.4 grams of poly beta dimethylaminoethyl methacrylate.  The pulp contained sufficient inorganic cations to cause incipient flocculation which was completed by the cations from the polyelectroylte which finally aggregated the wood pulp particles. The treated suspension was filtered through a fine wire screen depositing a freely filtering layer which was subsequently calendered to form a cellulosic sheet.  (5) An aqueous suspension of a washed kaolinitic clay which suspension did not contain sufficient inorganic cations to flocculate the clay particles was treated with gradually added incremental amounts of a dilute aqueous solution of polyvinylpyridine hydrochloride whereupon a precipitation commenced at a polyelectrolyte concentration of 15.0 micro-normal units per litre with an optimum settling rate at 159 micro-normal units. Further examples deal with the treatment of clay suspensions with a polyvinylpyridine butyl bromide quaternary salt solution, a polyvinylpyridine hydrochloride solution which had been neutralized with caustic soda, and a solution of poly beta dimethyl-aminoethyl methacrylate hydroacetate neutralized with caustic soda. Specification 723,869 [Group VIII], is referred to.  Reference has been directed by the Comptroller to Specification 723,868.ALSO:Aqueous liquors containing suspended negatively charged particles, which are in a flocculated condition due to the presence of inorganic cations in a quantity sufficient to neutralise the charges of the particles, are treated with a cationic polyelectrolyte in an amount not more than 0,1 per cent by weight of the liquor treated so that the particles become aggregated and separable from the liquors.  The cationic polyelectrolytes are water-soluble linear polymers or copolymers which form cations containing penta-valent nitrogen atoms when dissolved in water.  The inorganic cations may be provided by inorganic salts naturally occurring in the liquors to be treated or deliberately added.  Alternatively the cationic polyelectrolyte can be used both to convert the negatively charged particles into a flocculated condition and then to aggregate the flocculated particles without inorganic electrolytes being present. The liquors treated may be waters of natural or artificial origin such as trade effluents or waters from fish ponds or lakes and the process may be applied to the recovery and treatment of clays, the preparation of pigment and the production of paper and textiles. Suitable polyelectrolytes are salts with acids of polymers or copolymers containing amino groups, for instance amine salts obtained by hydrochloric or acetic acids; amine salts of a homopolymer of a dialkylaminoalkyl ester of an a b  ethylenically unsaturated aliphatic carboxylic acid such as acrylic or methacrylic acid, or of a copolymer of a dialkylaminoalkyl ester of an a b  ethylenically unsaturated aliphatic carboxylic acid such as acrylic, methacrylic or maleic acid with an olefinic compound copolymerizable therewith, for example styrene.  Other suitable amine salts are salts of polymers or copolymers containing pyridine nuclei or a copolymer of vinylpyridine with an olefinic compound such as acylonitrile.  The polyelectrolyte can also be a quaternary ammonium salt for example formed by the interaction of an aliphatic or heterocyclic tertiary amine with a homopolymer of a vinyl ester of a saturated halogenated aliphatic monocarboxylic acid such as polyvinyl chloroacetate.  Polyacrylamide, polymethacrylamide or an acrylamide acrylonitrile copolymer may be used.  Examples of polyelectrolytes, the preparation of which is given (see Group IV(b)) are polyacrylamide, polydimethylaminoethyl methacrylate, acrylamide-acrylonitrile copolymer, methacrylic acid (35 per cent)-dimethylaminoethyl methacrylate (65 per cent) copolymer, styrene-maleic acid copolymer-b  dimethylaminoethyl half-este