By Jessica Roulhac

Professor of Textile Engineering, Chemistry and Science Ahmed El-Shafei in the Wilson College of Textiles knows that sustainability is an evolving concern within the textile industry. Leaders in the field must navigate production demands to create attractive and rich shades of fabrics. At the same time, they are challenged to reduce waste while saving energy, water and chemicals.

Dr. El-Shafei is zeroing in on the problem of textile wastewater formation. Wastewater is the liquid waste that remains after a fabric has been dyed or a textile finish has been applied. As an expert in the field of color chemistry, El-Shafei feels led to either find an existing solution or create a new one.

“We are the premier institution in the world,” he says. “We have a big job to provide approaches to make the industry more sustainable.” 

In 2017, the Walmart Foundation funded his research that is dedicated to creating a more sustainable textile dyeing process. This research has three goals in dyeing textiles: use zero salt and alkali, produce no wastewater and achieve at least 95% in savings on energy and water consumption.

Partnerships that produce

El-Shafei’s team identified a partner for their research: JB Martin Company, a top producer of woven velvet fabrics. The textile dyeing process took place at the company’s facility in Batesburg-Leesville, South Carolina. The team used a foam machine developed by Gaston Systems Inc. to then convert their dye bath into a shaving cream-like foam and then apply it to the pre-treated fabric without the use of salt or alkali. 

Students on the team had hands-on experience with a new pre-treatment process, too. They treated cotton fabric in a continuous process with their sustainable proprietary chemistry to create a large number of dye sites that act as a magnet for dye molecules. The dye bath was then converted to foam and applied directly to the fabric. Within minutes, they produced a dyed fabric that left zero waste. There was no need to wash, rinse or dry the fabric.  Furthermore, their sustainable chemistry does not create any smell in the fabric. 

The dyed fabric passed quality-control tests that deliver comparable results to traditional dyeing methods. One example: No color transfer. Additionally, the process passed various colorfastness tests. Colorfastness to light demonstrates how well a fabric resists fading when exposed to sunlight. Colorfastness to washing shows how well a fabric can withstand washing machine cycles with laundry detergent without changes in color characteristics. 

Following completion of his Ph.D. studies, one of the students, Shahriar Salim began his new role as a textile engineer with JB Martin Company. A little more than a month before, he successfully defended his Ph.D. dissertation in fiber and polymer science. He could not have predicted that participating in a research project would lead to his first job after graduation.

“The Wilson College is a great resource,” Dr. Salim says. “It will allow you to learn new things. It will not only provide you the opportunity to work in the field of science, chemistry or engineering, but also give you options of multiple career paths to explore.”

In his new role, Salim will be responsible for sustainable dyeing of cotton velvet. He will also perform color measurements and matching between different batches and predict dye recipes to guarantee repeatability and reproducibility. 

“Our team is grateful for the Walmart Foundation and JB Martin Company. Without their support, it would not be possible to reach this milestone in sustainable dyeing,” El-Shafei says

Dyeing and finishing in the future

While El-Shafei has achieved a victory in sustainable dyeing, what about finishing? El-Shafei, who is also director of the polymer and color chemistry (PCC) program in the Wilson College, dreams of a day when textile engineers and chemists develop a novel chemistry that achieves simultaneous sustainable dyeing and finishing that leaves zero wastewater. Think about wrinkle-free cotton, water- and oil-repellent clothing, antibacterial, antiviral or flame-retardant clothing. These finishing options could one day satisfy consumers without leaving behind harmful chemicals in the clothing or wastewater that impacts the environment.

“I hope one day my research team develops a dual-function chemistry to allow us to achieve simultaneous sustainable dyeing and finishing,” El-Shafei says.

How can everything that remains be recyclable? A challenge lies ahead for researchers to improve the industry, so the work does not stop. As current students and alumni like Salim become equipped, they will take their passion for sustainable dyeing and finishing wherever they go.

The poster above shows comparisons between cotton fabric dyed through sustainable and unsustainable processes.