Editor's Note: On the journey toward the stars and oceans, they walk side by side with the times; in the realm of education, they persevere and forge ahead with quiet dedication; in the oath to serve the nation, they stand firm and never falter. Today, on International Women's Day, the university's news center presents a special feature highlighting female educators who break barriers in teaching, research, and mentorship—women who uphold their passion with courage, challenge the unknown with resilience, and shatter constraints as they move forward, blooming like a vibrant tapestry of flowers.

The first encounter with Professor Lin Zhang took place in her office at the Jingui Building of the School of Metallurgy and Environment. At 54, her eyes sparkled with clarity. When the conversation turned to research, that clarity transformed into a radiant "light," illuminating her entire being with enthusiasm, soon enveloping those around her.

On February 17, the International Union of Pure and Applied Chemistry (IUPAC) announced its 2025 list of Distinguished Women in Chemistry and Chemical Engineering, naming Lin Zhang one of the 12 global honorees. For years, Lin and her team have dedicated themselves to heavy metal pollution control, integrating nanotechnology into the field. Their groundbreaking "nanocrystalline mineralization method" has provided a "new prescription" for addressing heavy metal pollution in China. This innovation earned her the Guanghua Engineering Science and Technology Award in 2024. For Lin, tackling pollution and advancing environmental protection have become the most meaningful pursuits of her life.

Professor Lin Zhang (second from left) guiding students in a scientific experiment.

Returning from Abroad, Restarting a Career

In 2004, Lin Zhang returned to China after five years of study in the U.S. During her time abroad, she underwent a significant life transition—becoming a mother to two children. While these "angels" brought her immense joy, motherhood also temporarily halted her career. "When I first returned, I felt somewhat lost about my future path," she recalled. To navigate this low point, Lin printed the words "Focus" on an A4 sheet and placed it by her computer as a constant reminder to immerse herself in her work. Today, those words still occupy a prominent spot in her office, though the humble paper has since been replaced by an elegantly framed calligraphy piece.

After overcoming this brief period of uncertainty, Lin resolved to restart her research. While reviewing the "Top Ten Environmental Cases" listed by China's environmental authorities, she was struck by the pollution incident at the Rongping Joint Chemical Plant in Pingnan County, Fujian Province. In 2006, Lin visited the site and encountered heavy metal waste for the first time. This field trip underscored the urgency of pollution control and solidified her determination to apply her knowledge to environmental protection—a long-held ideal. To realize this vision, she crossed disciplines from inorganic chemistry to environmental chemistry, aiming to fill the research gap in heavy metal pollution control in China.

Two decades ago, domestic industries relied on crude "reduction-stabilization" methods for treating heavy metal pollutants, often burying the waste without addressing the root cause. For instance, highly toxic hexavalent chromium could re-emerge over time, leading to secondary pollution through rainwater runoff. To tackle this issue, Lin and her students hauled bags of "yellow sludge" back to the lab, conducting thousands of observations. Their efforts revealed nanocrystalline phases in the chromium residue under electron microscopy—a discovery that challenged traditional environmental chemistry theories, which assumed heavy metals existed only in free or mineral states. Building on this insight, Lin explored whether these nanocrystals could be manipulated to achieve deep separation of chromium, ultimately leading to her pioneering "nanocrystalline mineralization method." By adding a specialized reagent to the waste, she transformed it into easily separable crystals, opening new avenues for hexavalent chromium pollution control.

Choosing Central South University, Growing with Purpose

Looking back at Lin's journey, "stepping out of comfort zones" emerges as a recurring theme. As a student, she twice declined guaranteed admissions to her home university to broaden her horizons elsewhere. Later, in her career, she worked at the Fujian Institute of Research on the Structure of Matter (Chinese Academy of Sciences) and South China University of Technology, continually exploring new directions.

Her connection with Central South University began in 2005 when she read a newspaper quote from Professor Chai Liyuan: "Chromium residue is a global challenge." This aligned perfectly with her research aspirations. Over her 16-year career in heavy metal pollution control, Lin sought to solve environmental problems through an interdisciplinary "engineering-science" approach. In the spring of 2020, to promote her mineralization-based resource recovery technology for heavy metal waste, she once again left her comfort zone, relocating from Guangzhou to Changsha to serve as Executive Deputy Director of the National Engineering Research Center for Heavy Metal Pollution Control.

Hunan, known as the "hometown of nonferrous metals," generates hundreds of millions of tons of heavy metal waste annually from its metallurgical industry. Conventional methods crudely extract valuable metals, leaving behind residues enriched with highly toxic elements like arsenic, thallium, and beryllium, which pose severe slow-release risks. To address this, Lin collaborated with Hunan Hanyang Environmental Protection and Saisi Environmental Protection, leveraging her "mineralization" theory to develop a technology for activating and stabilizing heavy metals at the nanoscale. This innovation formed a complete resource recovery system—"nanoparticle identification, mineralization separation, and interface stabilization"—solving the safe disposal challenges of hazardous heavy metal waste in metallurgical and chemical industries. Today, her "mineralization method" has been applied in two-thirds of China's key heavy metal pollution control regions, turning waste into treasure.

Lin also harnessed her interdisciplinary expertise to pioneer new research directions. In recent years, she merged data science with heavy metal pollution control, creating a shared database platform that catalogs the phase compositions of all 159 hazardous heavy metal wastes and 90 industrial solid wastes listed in China's National Hazardous Waste Inventory. This "treasure trove" of over 10,000 entries is freely accessible, helping researchers, policymakers, and industry professionals make informed decisions about pollution management.

Since receiving the IUPAC award, Lin has often been asked what advice she would give to women in STEM. Her answer: "Every step out of your comfort zone is nourishment for growth and progress. Be yourself—don’t let societal inequalities hold you back. Seize every opportunity to express yourself fully." Placing oneself at the center of the world, she believes, means recognizing that obstacles and biases may be stumbling blocks but never the final note. As echoed in her favorite folk song, El Cóndor Pasa: "I’d rather soar far away, like a swan, than be bound to the ground."

[First Reviewer: He Jiamin, Second Reviewer: Dai Yanyang, Third Reviewer: Wang Qinmeng]