TECHNOVATION ’12

TREATMENT AND REUSE OF REACTIVE

DYEING EFFLUENTS

•P.Elango•J.Majeed Ahmed Fazheel

•Mohammed Sathak Engineering college

INTRODUCTION Dye effluent treatment is the most challenging feature

for developing countries like India, so we need an economic and efficient steps to be developed.

An efficient process for treating the most reactive dyes from the exhaust process must be chosen.

Our idea is to get more reactive dyes from simple methodology using membrane separation with FOUR effective filtration process.

Thus environmental water degradation can be ceased, hence improving the recycling of dyeing effluents.

To stop old effluent non-functioning units and to restart with ceramic membranes of filtration process.

The legal regulations maintaining the limit values for the release of wastewater are changing and becoming increasingly severe, and also including the limits with respect to the salinity, should be managed.

NEED OF THIS STUDY On the global level, the demand for the supply of

freshwater is becoming more acute every day. In the dyeing of textile materials, water is used in the

form of steam for heating various treatment baths, and also to enable the transfer of dyes to the fibers.

After dyeing process has been completed, various treatment baths are drained out, including the former dye bath, which contaminates the water bodies.

They contain a very high salt concentration, heavily colored and also contains a substantial load of organic substances.

More than 80,000 tons of reactive dyes are produced and consumed every year, which makes it possible to estimate the total pollution caused by their usage.

In addition, these effluents exhibit a pH of 10–11 and a high temperature of 50–70◦C.

BENIFITS TO BE GAINED To remove cotton fibres and to control the carbonate

concentration which may strongly influence nanofiltration procedure.

The treatment of dye baths by nanofiltration, is in order to recover and reuse the sodium chloride and the water.

To select the NF membranes that are able to operate at high temperatures (50–70 ◦C), which allows passage of monovalent salts, while retaining the hydrolyzed reactive dyes.

Evaluation of Reverse osmosis process, was robust in terms of operating at elevated temperature (40–50 ◦C), able to operate at 80×105 Pa (80 bar) trans membrane pressure (TMP).

To obtain BOD/COD below .2 g/l

CHALLENGES OF STUDY

PROCESS DESCRIPTION The mechanism begins with dye bath, dye

permitation, dye exhaustation, and reactive dye examine.

The process proceeds from prefiltration, which includes lowering of pH and acidifying using HCL to remove cotton fibers.

Next, Nano filtration occurs to get more reactive dyes and allow to recycle with: Temperature lower than 20 ◦F pH 5.5–6.0.

Final deal to reverse osmosis is the reactive dye effluents.

And hence to analysis the efficiency by using conductometric titrations or potentiometric analyses or spectrophotometric methods.

EFFLUENT TREATMENT PROCESSCoagulant

/Lime/flocculant

Recycle/Reuse

Final Effluent

1 2 34

1. Screen2. Equalization Tank3. Flush Mixer4. Primary filtration5. Bio-reactor/AT6. Secondary filtration7. Sump8. Active Carbon Filter9. Sludge dewatering10. Sludge thickener11. SDB

5

67

8

Filter

91011

SOLUTIONS AND REACTIONS The reactive dyes used are of the following types:

1. Vinyl sulfone,2. Monochloro-difluoropyrimidine, 3. Monochlorotriazine, 4. Trichloropyrimidine and5. Monofluorotriazine.

Diagrammatically, a reactive dye has the form of a complex molecule which is constituted by a chromophore responsible for the adsorption and re-emission of light rays possessing solubilizing groups.

Onto which a reactive group is grafted which is fixed to the cellulose by means of a covalent bond. The type of reaction can be either one of substitution or addition: Mechanism of reaction by esterification Mechanism of reaction by etherification

MEMBRANE SELECTION

PREFILTRATION A Polygard CR filter and a Rigimesh filter supplied,

respectively, by Millipore and Pall Exekia were used. Thus, the prefiltration can be carried out at 70 ◦C. The experiment consisted in releasing the effluent at

the outlet of the dyeing machine into the prefilter. The pre-filtered effluent was then fed to the retention

tank for acidification and the textile fibres trapped by the prefilter were afterwards removed.

The acidification of the dye bath in order to precondition it for the passage through the membrane and its reuse for a new dyeing, is based on the use of hydrochloric acid (technical grade, 30%)

We successed by obtaining a 97% recovery of NaCl with same parameters.

VARIATION OF EFFLUENTS ON ADDED HCL

NANO FILTRATION The DESAL 5DL membrane used allow the

salts to pass through but retain the hydrolyzed reactive dyes and dye auxiliaries and resists has high temperatures (∼= 50 ◦C).

We have checked various parameters like permeate flux, initial reactive concentration, retention factor & also auxiliaries of dyes.

The effects of pH, temperature, retentive flux of the reactive dye are considerably reduced.

The TMP between the interface of the membrane should be maintained on 70psi to 90.5psi.

The filtrate contains more hydrolyzed reactive dyes.

NANOFILTRATION PROCESS

Variation of the NF membrane permeability vs. number of experiments.

REVERSE OSMOSIS We have decided to use membrane AD 2540 F (OSMONICS)

and to discuss the result obtain with this membrane. With membrane SC 2540, designed for briny water, the

retention factor of the salt was not found high enough when the salt concentration in the feed tank increases.

- Shade: same intensity, same hue.- Domestic laundry C2S ISO CO: no difference in terms of

shade degradation and bleeding on multifibres witness.- AATCC 61: same results than C2S ISO CO6.- Water fastness ISO E01: no difference in terms of shade

degradation and bleeding on multibres witness.- Perspiration ISO E04 (acid and alkaline) 5: same results than

Water fastness ISO E01.- Rubbing fastness X12 (wet and dry): no difference.- Light fastness: no difference between two dyeing in

terms of degradation and hue change.

DYEING PROTOCOL WITH (A) RECYCLED BRINE AND (B) USUAL WATER.

VARIATION OF SALT CONCENTRATION VS PERMEATE FLUX

The retention factors (RF) of the different species are calculated from the concentrations of each species in the permeate and in the retentate according to the following equation:

RF =(1 − Cp/Cr)× 100 where RF is the retention factor (%), Cp the concentration in the permeate (gL−1) and Cr is the concentration in the retentate (gL−1).

Retention Factor

NF

reverse

osmosis

prefiltration STEP

PLANSEQUENCE

ADVANTAGES OF THIS STUDY Compact: The place needed for the process

in the dye houses is small. Progressive: Fashions and colors changes,

treatment must take place at the outlet of the dyeing machine, regardless of the bath, yet be capable of recycling a maximum amount of water and mineral salts.

Flexible: Widely variable volume are capable of being treated.

Feasible: The quality of the water and of the brine should be constant, so as to be reusable for dyeing again.

CONCLUSION Finally, dyers have the possibility for

achieving the considerable savings of sodium chloride, with less pollution to the environment with salt loads and reduction in the consumption of fresh water.

The treatment process presented in this study permits the user to regulate the problem of coloration of the final effluents.

Practically, to reduce the pollution, not only by organic but also from mineral origin, as the effluents contain no further salt.

It permits a shorter term return on investment by only considering the cost of the primary material.

Thanking One and All…