CS242255B1 - Waste water treatment with sorbents - Google Patents

Abstract

The invention relates to a method for removing anionic dyes and anionic surfactants from aqueous solutions, in particular from wastewater, using insoluble cellulose derivatives of the general formula I Ofi R,, ΗΦ I R, !t ) where Ri and R2 are alkyls with a number of carbons from 1 to R3 is phenyl or benzyl, X- is an anionic residue of an organic or inorganic acid, or the OH- group, Cel is a residue of a cellulose macromolecule. This process makes it possible to remove from wastewater even such anionic dyes that are only difficult to remove by other processes.

Description

The invention relates to the removal of anionic dyes and anionic surfactants from aqueous solutions, in particular from dye wastewater using sorption materials.

Waste water producers of this type are mainly textile refineries. Waste waters from these sites contain, in addition to organic and inorganic impurities, a large amount of dyes and surfactants, which remain in the dyeing bath after the dyeing process is completed.

Washing water is also highly contaminated with dyes and surfactants. The vast majority of dyes and surfactants used are of anionic nature. They are mostly very soluble substances, which are difficult to remove from wastewater.

Biological treatment Waste water in any of the possible variants usually does not provide good discoloration. The dyes are not sufficiently biodegradable, so that the decolourisation of waste water in the biological system is only partial.

Therefore, chemical clarification is currently the most widely used method for textile waste water treatment, given the ability of this process to remove most of the dyes from the waste water.

Typical piroiblem of all types of clarification is excessive sludge formation, as well as its drainage and landfilling. The clarity also increases the salinity of discharged waste water, which is undesirable and legally limited.

Sorbent processes are also used (as a separate physicochemical step) in the decolourisation of textile waste waters. They have a number of advantages over other methods of treatment - insensitivity to wastewater toxicity, low demands on the building area, during the actual process no other substances are introduced into the wastewater.

At present, adsorption to granular activated carbon predominates. However, the disadvantage of activated carbon is the high cost and necessity of regeneration at high (temperatures). Recently, although regenerative processes have been found using selective solvents (isopropanol), they have not yet been widely used due to the unavailability of these solvents.

Other decolorization methods (ion exchangers, membrane approaches, electrochemical processes) are currently very expensive compared to conventional technologies, so that their industrial use is practically out of the question.

Most of the aforementioned drawbacks are solved by a sorbent wastewater treatment process which removes anionic dyes and / or anionic surfactants from aqueous solutions, especially dye waste water.

The method is characterized in that aqueous solutions of anionic substances are contacted with insoluble cellulose derivatives of the general formula I

R <»

I ⁷ ®

C 6 - O -CCH 2 CH ₉ -N-R a ^{X 1} of _t (I) wherein

R1 and R2 are alkyls having a carbon number of 1 to 4,

R 5 is phenyl or benzyl,

X ^- is an anionic radical of an organic or inorganic acid or OH,

Cell is a cellulose macromolecule residue at a temperature of <0 to 100 ° C.

The quaternary ammonium compounds capable of reacting with the cellulose macromolecule are mainly used in dyeing cellulose fibers. Cellulose fibers, in which a strongly cationic ammonium group (Formula I) is introduced by reaction with these substances, are able to take up anionic dyes to a much greater extent and bind them to each other.

¹ but this knowledge can be used in those cases where it is necessary from aqueous solutions of anionic dyes and other anionic materials removed. These are mainly disposal of undesirable colored and non-colored substances in waste water.

Removal of solutes from aqueous solutions using solid abrasives may have essentially two modifications. Either the sorbent is dispersed in solution with stirring and equilibrium is reached after separation of the two phases, or the aqueous solution is filtered through a filter in which the sorption layer is placed.

Removal of solutes from water is more often used. This purification method can advantageously be applied directly to sources of small volumes of concentrated waste water, eg at the effluent from the dyeing and washing machines. Lower volume equipment can be used to dispose of the contamination contained in these concentrated waste waters, thus positively affecting the treatment economy.

The proposed process of wastewater treatment consists in using a sorbent based on the principle of insoluble cationic cellulose derivatives which are able to bind ionic substances of an oleic nature.

Such sorption materials can be prepared by the action of compounds of formula II

N- (2,3-epoxypropyl) -N-benzyl-N, N-dipropylammonium chloride.

R 6 -N-CH 2 Y

R '(II) wherein

R1 and R2 are alkyls having a carbon number of 1 to 4,

R 5 is phenyl or benzyl,

X 'is an anionic residue of an organic or inorganic acid,

Y is -CH-CH2;

O or —CH — CH2

I I

OH Cl in the presence of alkali on a cellulosic substrate, preferably wood waste - sawdust, shavings or fibrous cotton waste.

The compounds of the formula do not react with the hydroxyl groups of the cellulose already cold. The cellulosic waste can be simply connected with their alkaline solution and after 8 to 12 hours the reaction is complete. The reaction can be accelerated by raising the temperature. At 60 degrees C, a reaction time of 60-90 minutes is sufficient. The reaction of the compounds of the formula II proceeds very well by drying their alkaline solutions on cellulose substrates at a drying temperature of 100 to 150 ° C.

The useful dynamic sorption capacity of the sorbent can be determined by flowing the purified aqueous solution through the sorbent filter layer. The color of the aqueous solution is monitored at the filter outlet.

The end of the test was indicated by increasing the color of the outflow above the selected limit, the value of which was determined to be 9% of the color of the inflow. The useful dynamic absorptive capacity corresponds to the weight amount of dye retained by the sorbent weight unit until the color of the effluent is increased above the selected limit.

Examples of compounds of the formula include:

The following examples describe the preparation of sorption materials as well as their use:

Example W

Spruce sawdust weighing 1 ΌΟΟ g shall be equally bonded in a suitable container with 1000 ml of a solution containing g. ^_1 1 N- (3-chloro-2-hydroxypropyl) -N-benzyl-N, N-dimethyl ammonium chloride 20 g. Even ^-1 NaOH.

The bath temperature is 20 ° C. The bath is left on the sawdust for 12 hours. On ivhoid. nets, the sawdust is washed with water to remove excess alkali. Thus, this material is ready for use as an anionic sorbent.

Cellulose derivatives and other compounds mentioned above were prepared in the same manner.

Example 2

Sorbent preparation procedure as in Example 1 except that beech sawdust was used and N- (3-chloro-2-hydroxypropyl) -N-phenyl-N, N-dimethylammonium sulfate was used as reagent.

The test to determine the dynamic sorption capacity of the sorbent thus prepared was carried out in a 19 mm tube, 460 mm long, which was filled with a 17 g sorhent. The filter inlet contained:

100 mg. I “ ¹ dyes Direct black No. C. 1.19 0.25 g. 1-Na 2 CO 3 g. 1-1 NaCil

The flow rate through the laboratory filter was ml.h ^-1 . The color of the outflow from the filter was monitored. The end of the test was indicated by increasing the color of the outflow above the selected limit, the value of which was determined to be 5% of the color of the inflow.

A useful dynamic sorption capacity c of ₅ %, which corresponds to the weight amount of dye retained by the sorbent weight unit until the color of the effluent exceeds the selected value, was determined to be 41 g dye / kg sarbent.

Example 1 a d 3

N- (3-chloro-2-hydroxypropyl) -N-benzyl-N, N-dimethylammonium chloride, N- (3-chloro-2-hydroxypropyl) -N-phenyl-N, N-dimethylammonium sulfate,

N- (2,3-epoxypropyl) -N-phenyl-N, N-diethylammonium acetate,

The sorbent preparation procedure was the same as in Example 1 except that the reagent was N- (2,3-epoxypropyl) -N-phenyl-N, N-diethylammonium sulfate.

The dye adsorption proceeded in the same manner as in Example 2, except that the feed contained the following components:

100 ml. ¹ “ ¹ Dyes Reactive Blue CI No. 82

5.5 g. 1-1 NU2CO3 40g. NaCl.

The useful dynamic sorption capacity of c ₅ o / o was determined to be 29 g dye / kg sorbent.

Example 4

The sorbent preparation procedure was the same as in Example 1, except that the reagent was N- (2,3-epoxypropyl) -N-benzyl-N, N-dipropylamionium chloride.

The dye adsorption proceeded in the same manner as in Example 2, except that the feed contained the following components:

100 ml. l-i dyes Acid black No. C. I. 26

2.5 ml. l-i NaSO.

Feed pH adjusted to 6.6. The useful dynamic sorption capacity was determined to be 11 g dye / kg sorbent.

Example 5

The sorbent preparation procedure was the same as that of Example 1. The useful sorption capacity was determined in accordance with Example 2, except that the useful dynamic was determined. absorption capacity for absorption of non-active surfactants. The filter feed contained 250 mg of a detergent with the active ingredient allyl polyglycol ethers sulfate.

The end of the test was indicated by increasing the concentration of the active ingredient in the effluent above a value corresponding to a 5% concentration of this ingredient in the inflow. The anionic sulfate present was determined by a selective photometric method with methylene blue.

Results are given in mlg. I ^"1 n-dodecyl sulfate (DDS), which is used as a standard. The useful dynamic sorption capacity c ^50/0 was determined to be 36 g DDS / kg sorbent.

Example 6

The sorbent preparation procedure was the same as in Example 2. The adsorption of the anionic surfactant was performed as in Example 5, except that the inflow contained 250 milligrams. 1 of a detergent with the active ingredient sodium diethylsulifojantairan. It was determined by dynamic useful sorption capacity of ₅ c / _c 44 g DDS / kg sorbent.

Example 7

The waste water from the dyeing apparatus is filtered through a sorbent-filled filter prepared according to Example 1.

In the dyeing apparatus, cotton yarn 34/2 is processed on cross-wound bobbins (yarn weight 60 kg) in a bath containing:

% wt. dye material Reactive Blue No. C. I. 4 g. 1 - 1 NaCl g. Na-COs

0.2 g. Of a wetting agent (TTP containing diethylsulfonate sodium succinate).

This is followed by usual washing. The combined waste water from dyeing and piranha at a temperature of 50 ° C is fed to the sorption layer filter for 6 hours.

Technological parameters of the sorption process: residence time 30 minutes, surface load 2 m. H'i. The inlet color was reduced by ¹ 80%.

Example 8

The waste water after dyeing the cotton ribbon in the bath is filtered through a sorbent-filled filter prepared according to Example 1. The dyeing bath contained:

1.4% w / w Material of the dye Direct Orange No. C. I. 37

0.4 wt. Dye material Direct! red No C. I. 23

0.6 g / l NaCl

1.0 g / L Na 2 CO 3

0.5 g / l surfactant (TTP containing sodium diethylsulfosuccinate)

1.5 m / l water treatment product (TTP containing ethylenediaminotetraacetic acid tetrasodium salt).

The spent 20 ° C dyeing bath is fed to the sorption layer filter for 216 hours,

Technological parameters of the process: residence time 20 minutes, surface load 2.5 m. h ^_1 . The color of the inflow was reduced by 70%.

Claims (1)

SUBJECT OF THE INVENTION A process for the purification of waste water by means of sorbents which "removes anionic dyes and / or anionic surfactants from aqueous solutions, in particular from wastewater," characterized in that aqueous solutions of anionic substances are contacted with insoluble cellulose derivatives of the general formula I kde R1 and R2 are alkyls having a carbon number of 1 to 4, R 5 is phenyl or benzyl, X ^- is the anionic residue of an organic or inorganic acid or OH ^- ;