Page 136 - CW E-Magazine (17-9-2024)

Point of View

Substituting with safer chemicals
About 1,500 chemical substances are known to be used in making textile products, often in cocktails containing several. The hazards
and risks associated with some (not all) have been assessed and safer substitutes are more often than not available. Several ‘eco-labels’
that proliferate in the industry offer brand-owners the comfort that safe chemistry has been used, and none from a deadly bunch of endocrine
disruptors, persistent organic pollutants, carcinogens, mutagens, repro-toxins, etc. Safer durable water repellency, anti-microbial and
wrinkle-free finishing chemistries are now available.

In short, sound chemical management has become an integral part of textile processing, and aiding sustianbility efforts in the industry.

End-of-pipe treatment for effluents
Thanks to mounting regulatory pressures, several chemical and/or biological processes have been developed for the treatment and
management of wastewaters generated during dyeing. In several of India’s major textile processing hubs – Tirupur in Tamil Nadu comes
immediately to mind – mandates of Zero Liquid Discharge have come to be accepted by the industry and, thanks to generous government
support, now widely practiced. This has improved the perception of the industry both amongst customers and the public.

There is also a shift in the approach for wastewater treatment and the focus is now on resource recovery. Technology options include
advanced oxidation processes, membrane filtration, microbial technologies, bio-electrochemical degradation, photocatalytic degradation,
etc.

Polyester recycling
Given the dominance of polyester fibre (~55% share of global fibre production) – both by itself and largely in blends with cotton –
polyester recycling is critical to a circular textile economy. Much of the polyester recycled today comes from PET bottles, not fabric, and
is through chemical recycling which reconverts shredded bottles to its chemical precursors, which (after some clean-up), are used to
resynthesise polyester resin. Regulatory concerns have prevented their use to make bottle-grade resin (bottle-to-bottle recycling), but
bottle-to-fibre recycling is today being done at scale. India has a large and growing PET recycling industry and one of the highest recycling
rates for this polymer anywhere in the world. So much so that the quantum of PET waste available in the country is inadequate and has
to be bridged by imports.

Recycling polyester in textiles is much more challenging. The variety of garments in style, materials and fibre materials, makes sorting
and dismantling for recycling laborious. Contamination, presence of colorants (dyes & pigments), finishing agents, and trims & accessories,
further complicate recycling efforts and increase the energy demands significantly. As a consequence, currently, the only widely available
option for recycling blended fabrics uses mechanical methods to shred the fabric. The resulting “shoddy” or “flock” is used in low-value
applications including building insulation and nonwoven fabrics.

Creating truly circular loops at scale will require action from all parties throughout the supply chain, including fibre-to-fabric manufacturers,
processing houses, brands & e-commerce sellers, customers, national & local governments, and NGOs. This is only now beginning to
happen, and advocacy groups focused on the circular economy are asking brands to look for fibre recycling solutions. As a result, leading
brands are looking for ways to source more materials from recycled products, collecting used apparel for recycling at stores, and telling
their customers about the sustainability benefits of recycled materials.

Biobased materials
Bio-based synthetic fibers are produced by chemically or biologically synthesizing renewable organic materials. Currently the global
bio-based synthetic fiber market is dominated by polytrimethylene terephthalate, fibers, polylactic acid fibers, and polyamide fibers. But
polybutylene succinate fibers, polyhydroxyalkanoates fibers, and several others show promise. The advancement of biotechnology and
biomimicry is expected to drive innovation in more exotic materials, currently produced only in a limited manner. Examples include spider
silk proteins produced through recombinant methods which exhibit exceptional strength or mycelium-based leather substitutes made
from the root structure of mushrooms that look identical to natural hide leather.

The textile industry is experiencing a profound shift towards sustainability driven by the urgent need to address environmental
challenges. From adopting ecologically conscious fibers to implementing resource-efficient equipment and promoting circularity, it is
redefining practices.
Ravi Raghavan

136 Chemical Weekly September 17, 2024

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