Probiotic Technology- A Novel Approach in scouring of Textiles

Swati V Chavan^1,2*, Karun Tyagi^1,2, Anubhav Sharma^1,2, Sadannavar MK^1,2 and Shital B Girmal^1,2
*Correspondence: Swati V Chavan, D. K. T.E Society’s Textile and Engineering Institute, Ichalkaranji, Maharashtra, India, Tel: 9420458122, Email:

Keywords

Pretreatment • Cotton • Probiotic • Scouring • Effluent • COD • BOD • TDS • TS

Introduction

In the conventional textile wet processing, the grey fabric has to undergo a series of chemical treatments before it turns into a finished fabric. This includes desizing, scouring, mercerization, bleaching and washing. The chemicals used for all these steps are quite toxic. In the various pre and post operations during fabric manufacture, the non-cellulosic and foreign constituents are removed partially or completely.

The use of probiotic chemicals in the textile industry is an example of white industrial biotechnology, which allows the development of environmentally friendly technologies in fibre processing and strategies to improve the final product quality. The consumption of energy and rawmaterials, as well as increased awareness of environmental concerns related to the use and disposal of chemicals into landfills, water or release into the air during chemical processing of textiles are the principal reasons for the application of probiotic in finishing of textile materials [1,2].

The cotton fibre is a single biological cell with a multilayer structure. These layers are structurally and chemically different and contain approximately 10% by weight of non-cellulosic substances such as lipids, waxes, pectic substances, organic acids, proteins/nitrogenous substances, non- cellulosic polysaccharides, and other unidentified compounds included within the outer layer of the fibre. These non- cellulosic materials create a physical hydrophobic barrier which protects the fibre from the environment throughout development; they provide lubrication during textile processing and affect the enhancement of the fabrics wettability and absorbency.

The common industrial removal of these impurities is conventionally carried out by treating the fabric with sodium hydroxide. Although alkaline scouring is effective and the cost of sodium hydroxide is low, the process is costly because it consumes large quantities of energy, water, and auxiliary agents. The strict pH and temperature requirements for alkaline scouring are damaging too many fibres. The treatment is generally at a high temperature 80-100°C, employing strongly alkaline solutions of the scouring agent, e.g. pH 13-14. Due to the non-specific nature of chemical processes not only are the impurities but the cellulose itself is attacked, leading to damages in strength or other desirable fabric properties. Furthermore, the conventional scouring process can cause environmental problems due to the highly alkaline effluent from these processes [3,4].

The scouring stage prepares the fabric for the optimal response in bleaching. An inadequately scoured fabric will need a higher level of bleach chemical in the subsequent bleaching stages.

Comparison between conventional scouring and bioscouring

Raw fibres, yarns or fabrics have various kinds of impurities like motes, seed coat fragments, pesticides, dirt, chemical residues, metallic salts of various kinds, and immature fibres. External impurities are removed in the blow room processing while internal impurities of cotton fibres removed by scouring processes. Cotton fibre is constituted with different layers in its body. Different constituent of cotton fibres are cellulose (90%- 94%), waxes (0.6%-1.3%), pectic substances (0.9%-1.2%), protein (0.6%-1.3%), ash (upto 1.2%), organic acids (upto 0.8%) and others (1.2%). The main target of scouring is to remove waxes, pectins, hemi-celluloses and minerals from the raw cotton fibres during the early stage of textile wet processing to make the fibres highly absorbent, which is necessary for the subsequent processes such as mercerizing, bleaching, dyeing, printing and finishing. For this purpose, Caustic soda (NaOH) treatment is used in conventional scouring, whereas, Enzymes (Cutinases, Pectinases etc.) treatment is applied in bioscouring process. Though Different scouring materials are used in the textile industry like NaCO₃, Ca(OH)₂ etc., alkaline (NaOH sodium hydroxide) is used mostly for the scouring. Conventional chemical scouring is done in hot (90°C-100°C) NaOH solution for 45-60 minutes. The conditions depend on the quality of scoured fabric required. Moreover, different agents are used such as reducing agents, detergent, sequestering agent (also called chelating agents or sequestering) and wetting agent. Sequestering agent reduces the water hardness, reducing agent prevent oxidation of cellulose by air oxygen at high pH, detergent acts as emulsifier to assist in removing waxy substances and wetting agent reduces the surface tension of water helps fibres to swell. However, use of enzymes in textile wet processing has added a new line research and likely eco-friendly substance to give a good solution to the problem of highly toxic chemicals causing environmental pollution. Enzymes, generally, act in low temperature with excellent efficacy [5,6]. It saves high cost of energy consumption compared to conventional process. Moreover, it reduces Biological/Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD), and other waste water effluent load thus reduces ETP operational cost. The fabrics treated with harsh chemicals are also unsafe for human health but bio-scoured fabrics are completely safe.

Probiotic technology

Probiotic bio-chemicals are metabolites derived from a fermentation process of natural selected raw materials and a consortium of probiotic microorganisms. The organic molecules from the ingredients used during the fermentation break down, maintaining their functional groups. These groups are responsible for conferring specific properties that are useful during processing operations like textile scouring [7,8]. Such properties, namely hydrating, solubilizing, dispersing, and degreasing, can replace chemical or biological auxiliaries like surfactants and enzymes. Alternatively, such properties can synergistically improve the performance of traditional auxiliaries. This application has a positive impact on effluent pollution [9,10]. Probiotic scouring makes it possible to effectively scour fabric without negatively affecting the fabric or the environment. Hydrolysis by probiotic such as pectinases promotes efficient interruption of the matrix to achieve good water absorbance without the negative side effect of cellulose destruction. This process is called probiotic scouring [11-13]. It breaks down the pectin in cotton and thus assists in the removal of waxes, oils and other impurities. The optimum temperature is 90-95°C and pH between 9 -11. The fabric gives better wetting and penetration properties.

Plan of work

List of materials and chemicals:

• Substrate: 100% cotton woven fabric with gsm 110 and 100% cotton hank of 40s count.

• Chemicals used: Sodium hydroxide (NaOH) LR grade.

• Auxiliaries: Commercially available Sequestering agent, Wetting agent and Detergent, ProScour obtained from Proklean Technologies Pvt. Ltd

• Equipment: Rota dyer machine, Laboratory Oven, Electric balance

Methodology

Conventional scouring

Conventional scouring was carried out using below mentioned recipe based on weight of the cotton material and maintaining MLR 1:30 at 95°C for 45 min in Rota dyer machine.

1. Wetting agent- 0.5%,

2. Sequestering agent- 0.3%,

3. Detergent- 0.1%,

4. NaOH- 2.5%

After the completion of the scouring process the samples were rinsed twice with hot water and cold water respectively and squeezed properly followed by drying in oven.

Probiotic Scouring

Probiotic scouring was carried out by using the following recipe on the basis of weight of cotton material and maintaining MLR 1:30 at 95°C in Rota dyer machine.

1. Wetting agent - 0.1%

2. ProScour- 1%

3. NaOH- 1%/1.5%/2%

After the completion of the Probiotic scouring process the samples were washed with hot water and cold water then squeezed properly followed by drying in oven.

Testing

The effectiveness of process was assessed by checking the tensile strength, tearing strength, absorbency, weight loss of the cotton material. Also the effluent was tested for Total solids (TS), Total dissolved solids (TDS), Total suspended solids (TSS), Chemical oxygen demand (COD) and Biological oxygen demand (BOD).

Conclusion

In this study an attempt was done to find out the suitability and adaptability of probiotic scouring over conventional scouring process. The prospect of probiotic scouring over conventional scouring can be better judged from the following conclusive results.

• Fabric strength: It was found that, with Probiotic scouring, there is less strength loss in the fabric (both warp way and weft way) as well in yarn stage when compared with conventional scouring method.

• Weight loss: Since 30-50% less caustic is used in Probiotic technology, it has a strong impact on weight loss of the substrate. It was found that in the case of conventional scouring of fabric and hank, the weight loss is more than that of probiotic scouring.

• Effluent parameters: There has been stronger impact on the parameters of effluent when both the scouring methods were compared. The effluent parameters like total solids (TS), total dissolved solids (TDS), COD and BOD were comparatively less in Probiotic technology than conventional method which provides greater contribution in saving the load on ETP as well the cost of effluent treatment too.

• Scope: From the results of the study, eco-friendly probiotic scouring process shows wider scope to substitute the conventional scouring process of cotton substrates.

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