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How to use water in textile dyeing



An abundant supply of water is necessary in order to run a dyeing and finishing plant.dye houses are usually located in areas where the natural water supply is sufficiently pure and plentiful. Water is used extensively throughout textile processing operations. it is ubiquitous solvent for dyes, chemicals. Rinsing and washing consumes enormous amounts of water. Steam is still the major heat transfer media for dyeing and finishing. Source of water
1. Rain water
2. Surface water
3. Subsoil water
4. Deep well water

Water standard for dyeing house:
Characteristic            permissible limit                                 
Color                                     colorless
Smell                                     odorless
Ph value                                Neutral ph   7-8
Hardness                               below 5 dh
Dissolved solid                     below 1 mg/l
Inorganic salt                        <500 mg/l
Iron                                         <0.1mg/l
Manganese                            <0.01 mg/l
Copper                                    <0.005mg/l
Nitrate                                     <50mg/l
Nitrite                                       <5mg/l
Consistent water quality plays a very significant role in the success of textile wet processing operations. Generally, process water should have little or no chlorine. low metals content(i.e iron and copper) and low salts concentration (i.e, chloride and sulfate). Alkalinity, ph and color. water hardness is one of the major factors which should be concern.
Surfactant of water:
A surface active agent is a chemical compound which, when dissolved or dispersed in a liquid is preferentially absorbed at an interface and reduce the surface tension between it and other liquid. The characteristic feature of a surfactant molecule is its two ends attached by a covalent bond. the two ends have diametrically opposed polarities. the non polar end(Hydrocarbon chain) is hudrophobic and polar end is hydrophilic. They are usually organic compounds that are amphipathic,meaning they contain both hydrophobic groups  and hydrophylic groups. Therefore they are typically sparing soluble in both organic solvents and water. Surfactants reduce the surface tension of water by absorbing at the air water interface. many surfactants can assemble in the bulk solution into aggregates that are known as micells. The concentration at which suractants begin to form micelles is known as the critical micelle concentration or CMC. Surfactants lower the surface tension of qa liquid,allowing easier spreading,and interfacial tension between two liquids.The term surfactant is a Contraction  of “surface active agent”
Classification
Surfactants are classified according to use, to ionic charge and to chemical structure.
By use it can be classified as:
1.Wetting agent
2.Detergnt
3.Emulsifying agent
4.Dispersing agent
By ionic charge it can be classified as:
1.anionic
2.Cationic
3.Non ionic
4.Amphoteric
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