ORNL develops eco-friendly lubricant additives for marine turbines
Photo courtesy of Genevieve Martin, ORNL/U.S. Dept. of Energy

ORNL develops eco-friendly lubricant additives for marine turbines

Researchers at the U.S. Department of Energy’s Oak Ridge National Laboratory (ORNL) have introduced a new generation of lubricant additives designed to protect water turbine equipment while preserving aquatic environments. This innovative development could revolutionise the use of lubricants in marine turbines, which are essential for generating electricity through ocean and river currents.

With around 2.47 billion gallons of lubricating oil used annually in the U.S. alone, a significant portion of which eventually contaminates the environment, there has been a pressing need for more sustainable solutions. The ORNL team’s breakthrough involves the use of ionic liquids (ILs), which are non-toxic, biodegradable, and demonstrate remarkable performance in reducing friction and wear on turbine machinery.

The newly developed additives consist of ammonium phosphate and phosphonium phosphate ILs, which not only reduce friction by 50% but also decrease equipment wear tenfold compared to standard commercial gear oils. These enhancements meet federal standards for environmental safety and biodegradability, as published in the journal ACS Sustainable Chemistry & Engineering.

Jun Qu, who leads ORNL’s Surface Engineering and Tribology group, explained the significant impact of these additives, “Our previous work showed us that you could dramatically increase the performance of lubricants with the addition of just 1% or even a half-percent of ILs. This time, we’ve tailored these additives specifically for aquatic environments, ensuring they pose minimal risk to ecosystems.”

Environmental concerns were paramount in the development process. ORNL’s Biodiversity and Ecosystem Health group, led by Teresa Mathews, focused on ensuring that the additives were effective, non-toxic to aquatic life, and capable of rapid degradation in the event of a spill. “We want them to degrade very rapidly,” if they enter the environment, Mathews said.

The toxicity and biodegradability of these ILs were rigorously tested at ORNL’s Environmental Toxicology Laboratory. Using water fleas, a key indicator species due to their sensitivity to pollutants, researchers found that the new IL additives did not adversely affect these organisms, marking a significant advancement in reducing environmental impact.

The project, which builds on more than two decades of IL research at ORNL, is set to move into further development phases, particularly focusing on lubricants for tidal turbines in oceanic conditions. These turbines face unique challenges such as seawater contamination, pressure extremes, and temperature fluctuations.

This initiative represents a major stride in green chemistry, bridging the gap between advanced material sciences and environmental sustainability. The collaboration within ORNL underscores the laboratory’s commitment to tackling environmental and societal challenges through innovative science and technology.

For more detailed findings, the study is available in the ACS Sustainable Chemistry & Engineering journal, or visit phys.org for additional insights into the research.