Name:M.YOUSUFdiscipline: TS-2B

COMPARATIVE STUDY OF SCOURING METHODS

Scouring is an important pre-treatment operation in the processing of cotton and cotton blended materials.

INTRODUCTION OF SCOURING

Scouring is a purifying treatment of textiles. The term scouring applies to the removal of

impurities such as oil, wax gum, soluble impurities and solid dirt commonly found in textile material.

Scouring

•Remove all impurities such as oil , wax , fat etc from the surface of the fiber.•Produce the fiber more hydrophilic.• Increasing the absorbency and clean the fiber by use alkaline.•Removing the natural coloring matter of the cotton fiber.

Objective of Scouring

In natural fibers there in non-cellulosic materials create a physical hydrophobic barrier to protect the fiber from the environment throughout its development.

We remove the waxes and pectin are present in natural fibers . Pectin connects the waxy material to cellulose of the primary wall.

Natural fiber Scouring

Alkali scouring Bio Scouring or Enzymatic Scouring

Types of Scouring

ALKALI SCOURING

scouring is done in a hot aqueous solution of NaOH to remove hydrophobic components from the primary wall (e.g. pectin, protein) and the cuticle (waxes and fats).

In alkaline scouring the use of high concentrations of NaOH also requires.

Alkali Scouring

We use high concentration of NaOH to remove the pectin inside the cotton fiber.

A pectin is a cuticle layer of a cotton fiber.

In pectin there is in present (waxes and fats).

Why we use high concentration of NaOH?

It work on high temperature easily.

It remove all impurities.Easily Available

ADVANTAGES OF ALKALI SCOURING

Not Save energy Costly Fiber Strength Wastage of Water High Temperature Not time saving Ruff surface profile Not Environment friendly

DISADVANTAGES OF ALKALI SCOURING

BIO SCOURING

Bioscouring is a process by which alkaline stable pectinase is used to remove pectin and waxes selectively from the cotton fibre.

Pectinase, as the name suggests, hydrolyses pectins present in cotton as a non-cellulosic impurity.

This process is substrate-specific and does not alter the cellulose component.

It takes place at lower temperatures and does not swell or remove the seed coat fragments called motes, which can be beneficial when scouring for the 'natural look'.

Bio Scouring

Pectinase:-Pectinases are used for the removal pectic substances from cotton.

Lipases :- They are used for the removal of natural fatt (oil and waxes) substances from cotton

Proteases:- Proteases are enzymes that catalyse the hydrolysis of proteins.

Types of enzymes that are used for bio-scouring process

Removal of wax ( a major part being fatty acids)

is the critical factor for improved wetability.  Pectin functions as a ‘glue’ binding wax to the fiber. Pectin removal  does not by itself result in wax removal or improved wettability.      

Mechanism of bio-scouring

BIO-SCOURING

Bio-scouring

Blend of Enzymes-Pectinase + Protease

Removes Pectin, protein, Wax, Oil etc

Alkaline-scouring

Sodium Hydroxide

Remove Pectin, Protein, Wax, Oil, Cellulose

Comparison of Bio-Scouring and Alkali Scouring

Bio-scouring

Soft Handle

cellulose with complete removal of Impurities

No core Alkali neutralization, thus less washing cycle

Less TDS, COD, BOD

Alkaline-scouring

Harshness

cellulose with complete removal of Impurities and partial Callulose

Required core alkali neutralization, thus more washing cycle

More TDS, COD, BOD

Results of Bio and Alkaline scouring

Graph

Bio-scouring

Direct cost is more but Overall cost is less

(Grey to finished)

Alkaline-scouring

Direct cost is less

but Overall cost is more (Grey to finished)

Cost

Example. Examples of Bio-Scouring and Alkaline Scouring

Save energy Save cost Water saving Temperature saving Time saving Smoother surface profile(Fully retain cellulose structure) Lesser weight loss Environmental benefits Reduces effluent treatment process/ ETP cost

Advantages of Bio-scouring

Inability of removing of cotton fiber waxes. They don’t work on high temperature. The degree of whiteness is often less The process is not suitable for removing seed-coat

fragments and mote adequately.

Disadvantage of bio-scouring

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