Super Material Converts Dissolved Urea in Water to Energy

Imagine having a tool that can selectively extract urea from a water mixture and, at the same time, convert it into a clean energy source – hydrogen gas. Well, a research team at Worcester Polytechnic Institute in America has achieved just that. They announced in a study published in the Journal of Physical Chemistry Letters the development of a “super material” that not only extracts urea from water but also turns it into a valuable resource.

The Problem of Eutrophication

Urea is commonly used as a low-cost nitrogen fertilizer, posing environmental challenges when present in agricultural runoff and municipal sewage waters. Its discharge contributes to eutrophication, leading to negative impacts on the ecosystem. Eutrophication enriches the water flow with nutrients like nitrogen, stimulating the growth of algae and other aquatic plants, creating oxygen-depleted “dead zones,” adversely affecting aquatic ecosystems and human health.

This negative effect occurs when the algae and plants die and decompose, leading to increased oxygen consumption in the water. This can result in oxygen depletion and the formation of oxygen-deprived “dead zones,” harming fish and other aquatic organisms dependent on oxygen-rich water. This imbalance affects species diversity, distribution, and may lead to the domination of specific harmful algae over others.

Extracting hydrogen from urea adds value to the process of its removal from water (Shutterstock)

5 Attempts, 5 Obstacles

Prior to the recent breakthrough at Worcester Polytechnic Institute, previous studies explored different methods to reduce or remove urea from water, including biological treatment, advanced oxidative processes, adsorption and filtration, electrochemical methods, and chemical precipitation. However, these methods faced challenges such as lack of selectivity in targeting urea, high energy consumption, limited scalability, and the introduction of additional chemical residues into the water.

Super Material… Promising Perspectives for Application

Building on previous experiments and challenges faced in widespread application, the researchers at Worcester Polytechnic Institute developed a method based on “selective electrochemical oxidation of urea,” using a non-polluting super material capable of efficiently handling large quantities of urea. This method creates added value by producing hydrogen gas from urea, offering the possibility of broad implementation.

According to a press release by Worcester Polytechnic Institute, the idea behind this material leveraged the unique properties of urea, particularly its high hydrogen content (6.7% by weight). Electrochemical analysis for hydrogen production from urea is believed to be more efficient and cost-effective in comparison to traditional water electrolysis.

January 2024 cover of the Journal of Physical Chemistry Letters celebrating the invention

This achievement can be summarized as follows:

1. First, material development: The researchers constructed materials using specific electron formations, specifically nickel and cobalt oxides and hydroxides.
2. Second, selective urea oxidation: The major achievement was making these materials selectively oxidize urea in a electrochemical reaction, targeting urea molecules specifically and converting them to other substances such as hydrogen gas without affecting the surrounding water molecules.
3. Third, electronic structure weaving: The researchers found that the success of selective oxidation lies in designing electronic structures for nickel and cobalt ions, targeting the dominant species – “nickel ions” and “cobalt ions” in the electron formation.

A New Era for Water-Energy Relationship

Khaled Abu Al-Azz, Professor of Chemical Engineering at the University of South El Minya (Southern Egypt), praised this research breakthrough, stating that it capitalizes on the existence of urea in water to herald a new era in the relationship between water and energy. By efficiently removing urea from water through electrochemical treatment, the researchers aim not only to address the pollution problem but also to generate hydrogen gas as a potential energy source.

The choice of urea for this work represents a clever move by the researchers, as it allows for the construction of an economical project for hydrogen extraction. It is one of the primary nitrogen fertilizers and feed additives produced in nearly 180 million metric tons in 2021.

However, while praising this achievement, Al-Azz pointed to the need for further studies to answer two key questions in practical application:

1. What is the long-term stability of the electrocatalysts used, and is there a possibility of degradation over time? How can the stability of the materials be improved for extended use?
2. How can this technology be integrated with existing water treatment and energy production systems? Are there potential integration aspects with other emerging technologies, and how can it adapt to water and energy infrastructure?

Al-Azz stated, “Certainly, researchers need additional studies to answer these questions, which could lead to further enhancements in electrocatalysts for increased efficiency and selectivity, or additional modifications to electronic structures or composition to improve their performance.”

By Source, the researchers at Worcester Polytechnic Institute have opened up new possibilities for addressing water pollution while simultaneously providing a potential clean energy source. Their breakthrough could revolutionize the water-energy relationship, offering sustainable solutions for both environmental and energy challenges.

Furthermore, the article emphasizes that the researchers set out to design electrocatalytic materials capable of selectively extracting and converting urea in an environmentally friendly and efficient manner. This achievement represents a meaningful step forward in the pursuit of cleaner energy solutions while tackling water pollution challenges.