CS215256B1 - A method of cleaning waste water from dyes and laundries - Google Patents

Abstract

The invention solves the problem of reducing the content of dyes in wastewater from dyeing and laundries. The essence of the invention lies in the use of sorption polymer powder materials based on polyester and polyamide. The effect of combined physical adsorption and chemisorption results in the preservation of dyes from the solution and thus their content is reduced. The invention can be used in the textile and chemical industry, wherever dyes in solution are used and where the dyed material is subsequently washed in an aqueous environment. The application of sorbents is preferably carried out by dispersing them in a given solution and subsequent separation of the sorbent with the captured dyes. The used sorbent can be regenerated with organic solvents or alkaline solution, thereby obtaining a sorbent powder for further use.

Description

The invention relates to a process for the treatment of waste water from dyes and laundries containing organic and inorganic dyes by means of polyester and polyamide-based sorption polymer powder materials in the form of homopolymers, copolymers and mixtures thereof. The purification is carried out by a combination of physical adsorption and chemical adsorption, whereby the dyes are retained on the sorbent used, which can then be regenerated with an organic solvent.

In addition to organic and inorganic impurities, waste water from dyeing and laundries contains a large amount of dyes, which remains in the bath even after the dyeing process has been completed or is washed from the washed material during washing. In the commonly used biological purification, these dyes are only retained. partially, so they go to the recipients. Sometimes these yods are discharged directly into the recipient. This situation is undesirable both from an ecological and economical point of view, since with suitable treatment these waters can be used in a technological process.

At present, the waste water dyes are mainly removed by clarification, where the adsorption of the dyes on the flocs formed in the water from the clarifier takes place. This method can only be applied where industrial waste water treatment plants are built and has the disadvantage that the used wastewater increases the salinity of the wastewater, which is undesirable and is legally limited.

Another widespread method of removing dyes from wastewater is by adsorption to various active carbonaceous substances such as activated granulated charcoal and various butts. These substances form packings of adsorption columns and filters. The disadvantage of activated carbon is the high cost and generally the need for regeneration at high temperatures (1000 ° C), which is both operationally and economically demanding. In addition, activated carbon is inadequate on the market.

A modern procedure is the removal of some ionic dyes from wastewater using ion exchangers. However, this process is not applicable to all dyes and, due to the demanding regeneration of these ion exchangers, is also costly.

The main objective of the proposed treatment method is to provide an economical process for removing dyes from waste water to such an extent that the purified water can be reused in the production process, based on the use of reusable materials.

The proposed method of treatment takes advantage of the fact that the proportion of synthetic materials (fibers, foils, etc.) in industrial production is constantly increasing and that the best material for trapping dyes from wastewater after dyeing or washing is the polymeric material on the same base. For this purpose, the invention uses polymeric sorbent powders. The advantage of this process is that most of these powders can be cheaply prepared from wastes in the manufacture of fibers and other polymeric products.

The process for preparing suitable powdered materials from polymer precursors can be divided into two groups. The processes first utilize reprecipitation of polymers from mixed fluxes with melt solvents. An example may be the preparation of the polyethylene terephthalate powder according to U.S. Pat. No. 171923. The polyester is dissolved in the caprolactam melt at 210 ° C and the formed melt formed is cooled. The solidified melt is ground and caprolactam is extracted with water. Dry powders prepared by this method has a porous structure (macropore and mesopore volume of up to 2.5 cm ³ / g) and high surface area ^of 10-130 m / g according to the preparation conditions, a polyamide powder with a porous structure and high surface area can be prepared by reprecipitating From the caprolactam melt according to the GDR patent No. 8027. A sorbent resulting from the co-precipitation of polyester and polyamide according to U.S. Pat. No. 204415.

Processes for the preparation of second-class powder polymers utilize controlled degradation of polymer precursors (O. A. Battlsta, Mlcrocrystal Polymer Science, Mc Grow Hlll, New York 1975). This process is particularly suitable for the preparation of powdered cellulose. Polymeric pulverulent materials prepared according to the procedures of the first group are particularly suitable and useful for wastewater treatment. Powder sorbents can also be used in combination with inorganic porous materials.

The present invention is based on the fact that the dye intended for the colored polymeric material is adsorbed physically on the surface of a powder prepared from the same or an analogous polymer, while at the same time chemical sorption into the polymer substrate itself takes place. Unlike dyeing processes of whole polymeric substances such as fibers and foils, where the uptake of dye is limited by their structure (orientation and low specific surface area), adsorption of 1 diffusion (at chemosorption) occurs on the unoriented polymer powder of high porosity and specific density. surface faster. For this reason, 1 dye residue can be captured from the dye baths and wash water in this manner. In most cases, the proposed method reduces the oxygen consumption values of BODs and CODcr.

The process can be applied preferably directly to sources of wastewater contamination, i.e. to effluent from dyeing and washing machines. As water is usually discharged at a temperature of 60 - 80 ° C, the sorption efficiency is high and the proposed process can obtain water for direct use in the process. Thus, in addition to the environmental benefit, the proposed procedure 1 guarantees an economic benefit in the form of scarce energy and water savings.

Example 1

The dyeing bath containing 0.8 g / l of the disperse dye CI Disperse Blue 128, which further contained 1 g / l of (NHi) 2SO4 at PH 5 (treated with acetic acid) and 4 g / l of naphtholene and dlphenyl compound, was diluted 10x. After heating to 80 ° C was to the solution

The sorbent polyester powder was added in an amount of 2 g / l. After the powder was completely dispersed in the solution, the solution was filtered through filter paper (black tape). In this way, 90% dye was collected from the solution. The dye concentration was determined spectrophotometrically. The GHSKcr (chemical oxygen demand) value in the filtrate decreased by 10%.

Example 2

Adsorption of the dye was carried out in the same manner as in Example 1, with the 'exception that a dye bath were placed the following components: 2 g / l of the acid dye CI Acid Blue 113.5 g / 1 Na2SO4.10 H ₂ O and CH 3 COOH to adjust pH to The bath was diluted 5 times. At a dose of 3 g / l of sorption polyester powder, 90% of the dye was collected, and the CODcr value decreased by 50%.

Example 3

The procedure was the same as in Example 1 except that the polyamide sorbent powder was used in an amount of 4 g / l. In this way, 90% of the dye was collected and the CODcr value decreased by 30%.

Example 4

The procedure was the same as in Example 1 except that a mixed sorption powder with a polyester / polyamide ratio of 2 g / l was used. 90% of the dye was captured and CODcr decreased by 10 ° / o.

Example 5

The procedure was the same as in Example 2, except that 2 g / l of polyamide sorbent powder was used. 90% dye was captured and CODcr decreased by 50%.

Example 6

The procedure was the same as in Example 2 except that a mixed sorption powder as in the example was used in an amount of 3 g / l. 90% of the dye was captured and CODcr decreased by 50%.

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Example 7

The procedure was the same as in Example 1, except that the following components were added to the dyeing bath: 2 g / l of the direct dye C.I. Direct Blue 106.2 g / l of Na2CO3, g / l of NaCl. The bath was diluted 5 times. At a sorbent polyester powder dose of 4 g / l, 100% dye was retained, with CODcr decreased by 75%.

Example 8

The procedure was the same as in Example 1 except that the following components were added to the bath: 0.4 g / L of Reactive Red Dye 2 and 0.2 g / L of Na 2 CO 3. After hydrolysis, the bath was subjected to sorption purification with a sorption polyester powder dose of 5 g / l. To modify the dye, a cationic modifier (formaldehyde compound with dicyandlamide) was added at a concentration of 1 g / l. 90% of the dye was collected.

Example 9

Working wash water for the washing of cotton material containing reactive dyes, which was taken from the third wash tub of a conventional tub wide washing machine, was subjected to sorption cleaning analogously to Example 7. 90% of the dye was collected.

Claims (4)

Process for the treatment of waste water from dyes and laundries containing organic and inorganic dyes by means of sorption polymeric materials, characterized in that the dyes are captured by a sorption polymeric material based on polyester and / or polyamide, with a specific surface area of 5 to 150 m ² / g, which is brought into contact with the waste water in an amount of 1 to 10 g / l and is retained against leaching, optionally with the addition of a cationic modifier based on the reaction product formaldehyde with dlcyanediamide, added to the waste water before it material in a concentration of 0.5 to 5 g / l. VYNALEZU 2. The wastewater treatment method according to claim 1, characterized in that the purified wastewater is brought into contact with the sorbent polymer material as it passes through its layer. 3. The process of claim 1, wherein the treated wastewater is contacted with a sorbent polymer material in the form of a powder having a particle size of 0.001 to 0.1 mm. 4. A process according to claim 1, wherein the sorbent polymeric material is contacted with a waste residual and / or wash bath at a temperature of 20 to 95 [deg.] C.