Pulp mill waste becomes green solution to remove toxic dyes

University of Arkansas researchers found a new, environmentally friendly method to clean wastewater of toxic and carcinogenic dyes commonly used in the garment industry.

2025-09-27

(Press-News.org) Dyes like Congo red and methyl orange create brightly hued shirts, sweaters and dresses. But these commonly used azo dyes can be toxic, carcinogenic and are hard to remove from wastewater.

David Chem, a University of Arkansas chemical engineering Ph.D. candidate, developed an environmentally friendly solution to remove these dyes using a common byproduct of the pulp and paper industry.

Azo dyes are used in 60-70% of commercial textile production. The dyes dissolve easily in water and resist biodegradation, which makes them an environmental hazard. The runoff from garment plants has the highest concentration of azo dyes, but they also end up in municipal wastewater from washing clothes.

To remove azo dyes from water, Chem started with lignin, a low-cost, widely available biopolymer derived from plant cell walls. Each year, 50 to 70 million tons of lignin are produced by the pulping industry. Most of it ends up in landfills.

“Lignin extraction is hard to process. It has a complex structure,” Chem said. “It is underutilized as a biopolymer.”

The researchers first added phenol to powdered lignin, making its surface more reactive. Then amino groups were added to give the lignin a positive charge so it would bond with the negatively charged azo dyes.

This two step, dual-functionalization modification of lignin has been previously tested as a way to remove heavy metal ions, but the U of A researchers were the first to apply this approach to harmful dyes.

In the lab, the modified lignin removed 96% of the Congo red dye and 81% of the methyl orange dye. With this method, both the dyes and the lignin can be reused.

“The process is really scalable. It’s a relatively green process. And it is highly effective,” Chem said.

Chem published his results in the Journal of Polymers and the Environment.

The other authors, all from the U of A, are professor Keisha Bishop Walters, Chem’s dissertation director and chair of the Ralph E. Martin Department of Chemical Engineering; post-doctoral fellow Fatema Tarannum; and Samantha Glidewell, an undergraduate at the time of the research.

END

ELSE PRESS RELEASES FROM THIS DATE:

Sustainable generative AI: UCLA develops novel light-based system

2025-09-26

Today’s popular chatbots and image generators have a severe downside for the environment. These examples of generative artificial intelligence leave a substantial carbon footprint due to outsized energy demands. At the same time, the large amount of water used to cool the equipment behind generative AI depletes a finite resource that humans, other animals and plants need in order to survive. Additionally, running such models requires massive computational infrastructure, raising concerns about their long-term sustainability. Now, researchers at the UCLA Samueli School of ...

University of Phoenix publishes new white paper on microservice using achieved skills to build confidence between students and employers

2025-09-26

University of Phoenix today announced the publication of a new white paper, “Leveraging Achieved Skills to Improve Confidence Between Students and Employers,” authored by Francisco Contreras and Brandon Edwards of the University’s careers product team. The paper outlines how a record of a learners’ achievements and attested skills can help students and employers speak a common language of skills, and help working adult learners see where they may qualify—and where they are close—before they apply. “When learners can see verified, granular skills mapped from their coursework and experience—and employers can see the same—confidence ...

ASTRO: Targeted radioactive therapy for recurrent prostate cancer, new SBRT approaches, 5DCT-guided imaging advances and more

2025-09-26

Physicians and scientists from the UCLA Health Jonsson Comprehensive Cancer Center will share the latest research and clinical trial results at the 2025 American Society for Radiation Oncology (ASTRO) Annual Meeting, including studies on targeted radioactive therapy for recurrent prostate cancer, new approaches to stereotactic body radiation for prostate and head and neck cancers, advances in MRI- and 5DCT-guided imaging for more precise treatments, and innovations in patient-focused cancer education. At this year’s scientific meeting, Dr. Amar Kishan, executive vice chair of radiation oncology at UCLA and co-director of ...

University of Cincinnati Cancer Center members present radiation oncology research at national conference

2025-09-26

University of Cincinnati Cancer Center researchers will present abstracts at the American Society for Radiation Oncology (ASTRO) annual meeting Sept. 27 through Oct. 1 in San Francisco. Study evaluates safety, efficacy of head and neck proton re-irradiation Patients with head and neck malignancies face a high risk of disease recurrence and the development of secondary primary cancers. While surgery is the preferred treatment in these cases, it is not always feasible based on tumor location or prior treatments. An additional course of proton radiation therapy called re-irradiation can be ...

ASTRO 2025: At 10 years, SBRT comparable to surgery for early-stage lung cancer

2025-09-26

Study is the first to compare 10-year outcomes from surgery and a specific kind of radiation therapy known as SBRT (also called SABR) in non-small cell lung cancer Survival outcomes were similar, but the SBRT group had fewer side effects and potentially less financial burden Study further confirms radiation as an alternative for these patients, even in cases where the cancer is operable SAN FRANCISCO, Sept. 26, 2025 ― Researchers from The University of Texas MD Anderson Cancer Center will present new data at the American Society for Radiation Oncology ...

UVA Engineering team develops new way to build soft robots that can walk on water

2025-09-26

Imagine a tiny robot, no bigger than a leaf, gliding across a pond’s surface like a water strider. One day, devices like this could track pollutants, collect water samples or scout flooded areas too risky for people. Baoxing Xu, professor of mechanical and aerospace engineering at the University of Virginia’s School of Engineering and Applied Science, is pioneering a way to build them. In a new study published in Science Advances, Xu’s research introduces HydroSpread, a first-of-its-kind fabrication method that has great potential ...

Building trust in soil carbon as a climate solution requires stronger evidence

2025-09-26

In a comment published in Nature Climate Change, Mark Bradford, the E.H. Harriman Professor of Soils and Ecosystem Ecology, and Yale School of the Environment research scientists Sara Kuebbing and Alexander Polussa ’25 PhD, together with colleagues Emily Oldfield ’05, ’11 MESc, ’19 PhD, of Environmental Defense Fund (EDF) and Jonathan Sanderman of the Woodwell Climate Research Center, argue that the scientific evidence supporting soil carbon’s role in mitigating climate change ...

Blockchain technology could help build trust in restaurants

2025-09-26

While taste and price remain top priorities, more consumers are starting to consider the safety and sustainability of ingredients when dining out — a challenge that restaurants are working to address. To support this shift, researchers at the University of Missouri are investigating how a revolutionary technology that could allow consumers to track ingredients all along the supply chain will affect their decision-making processes. “Customers have become increasingly concerned about where their food is coming from, whether it’s sustainably sourced and how safe it is to eat,” Pei Liu, an associate professor of hospitality management in the College of Agriculture, ...

New study supports gene-tailored radiation doses to treat HPV+ throat cancer

2025-09-26

Genetic testing can identify patients with HPV-positive throat cancer who may benefit from lower radiation doses, according to Cleveland Clinic research. The study, published in the Journal of Clinical Investigation, builds on a growing body of evidence that radiation treatment can be personalized using tumor genomics, potentially shifting treatment approaches from the norm, where radiation is prescribed at a uniform dose, to one called Genomic Adjusted Radiation Dose (GARD), where radiation is prescribed to a desired effect. The current standard radiation dose for HPV-positive throat cancer is 70 Grays (Gy), which offers cure rates between 80% and 95% but can ...

New adaptive optics to support gravitational-wave discoveries

2025-09-26

RIVERSIDE, Calif. -- Gravitational-wave detection technology is poised to make a big leap forward thanks to an instrumentation advance led by physicist Jonathan Richardson of the University of California, Riverside. A paper detailing the invention, published in the journal Optica, reports the successful development and testing of FROSTI, a full-scale prototype for controlling laser wavefronts at extreme power levels inside the Laser Interferometer Gravitational-Wave Observatory, or LIGO. LIGO is ...