UV light holds promise for energy-efficient desalination – University of California, Riverside

Report on a Novel Solar Desalination Technology and its Implications for Sustainable Development Goals

Executive Summary

A research team at the University of California, Riverside (UCR) has identified a new method for solar desalination that utilizes deep ultraviolet (UV) light to separate salt from water. This non-photothermal process, detailed in a study published in ACS Applied Materials & Interfaces, employs an aluminum nitride ceramic wick and has the potential to significantly advance several United Nations Sustainable Development Goals (SDGs), particularly SDG 6 (Clean Water and Sanitation), SDG 7 (Affordable and Clean Energy), and SDG 14 (Life Below Water).

Introduction: Addressing Global Water Scarcity through Sustainable Innovation

The Challenge of Desalination and SDG 6

Ensuring access to clean water and sanitation for all (SDG 6) is a critical global challenge. Conventional desalination technologies like reverse osmosis are energy-intensive, contributing to greenhouse gas emissions and undermining SDG 13 (Climate Action). Furthermore, the discharge of toxic brine waste from these processes poses a significant threat to marine ecosystems, conflicting with SDG 14 (Life Below Water). There is an urgent need for innovative, sustainable, and energy-efficient desalination solutions.

A Novel Approach by UCR Researchers

A team led by Associate Professor Luat Vuong has demonstrated a breakthrough that leverages the high-frequency energy of deep UV light (approximately 200 nanometers) to break the molecular bonds between salt and water. This discovery presents a new pathway for desalination that could bypass the need for heat or high-pressure systems, aligning with the principles of sustainable industry and innovation (SDG 9).

Technical Findings and Methodology

The Role of Deep Ultraviolet Light

The core of the discovery is the use of a specific deep UV light channel to induce saltwater separation. Unlike traditional solar desalination that relies on dark materials to absorb heat and boil water, this method is non-photothermal. The research suggests that high-energy photons from UV light may be capable of directly cleaving salt-water bonds without heating the bulk liquid, representing a paradigm shift in desalination technology.

Material Innovation: The Aluminum Nitride Wick

The process was demonstrated using a wick made from aluminum nitride, a white ceramic material. The properties of aluminum nitride make it an ideal candidate for this application:

• Inexpensive and widely available
• Non-toxic and durable
• Highly hydrophilic (water-attracting)
• Crystalline structure suited for emitting UV light

The material may facilitate a process known as “photon upconversion,” where low-energy photons are combined to create a single, high-energy photon powerful enough to break the salt-water bonds.

Experimental Results

In controlled experiments, saltwater evaporation rates increased significantly when ceramic wicks were exposed to UV light compared to samples kept in the dark or exposed to other light spectrums (red, yellow, infrared). This confirms the unique efficacy of the deep UV channel for this process.

Alignment with Sustainable Development Goals (SDGs)

Primary Impact: SDG 6 (Clean Water and Sanitation)

This technology directly addresses Target 6.1 of achieving universal and equitable access to safe and affordable drinking water. By providing a potentially low-cost and scalable method for desalination, it could be instrumental in securing water resources for coastal and arid communities.

Supporting Goals: Energy, Climate, and Marine Life

• SDG 7 (Affordable and Clean Energy): By harnessing solar energy and avoiding the high electricity demands of reverse osmosis, this innovation promotes the use of clean and renewable energy for essential services.
• SDG 13 (Climate Action): A reduction in the energy footprint of global desalination operations would lead to a corresponding decrease in carbon emissions, contributing to climate change mitigation efforts.
• SDG 14 (Life Below Water): The technology offers a potential solution to the problem of concentrated brine disposal, a byproduct of reverse osmosis that is toxic to marine life. This helps protect and restore marine ecosystems.

Fostering Innovation and Responsible Production

• SDG 9 (Industry, Innovation, and Infrastructure): The research exemplifies scientific innovation that can build resilient infrastructure and foster sustainable industrialization.
• SDG 12 (Responsible Consumption and Production): This approach represents a more sustainable production pattern for freshwater, minimizing energy use and environmental waste.

Future Outlook and Broader Applications

Path Forward for Research and Development

While the discovery provides a clear path for innovation, further research is required to engineer systems for widespread use. The UCR team is now focused on designing system architectures, refining fabrication processes, and developing spectroscopic tools to better understand and optimize the light-driven evaporation process.

Potential for Diversified Applications

Beyond desalination, the wicking approach could be adapted for other processes that support sustainable development, including:

1. Waste management processes
2. Harvesting minerals in extreme environments
3. Developing salt water-based evaporation cooling systems as an alternative to traditional air conditioning

Conclusion

The development of a non-photothermal, UV-driven desalination method at UC Riverside marks a significant scientific advancement with profound implications for global sustainability. By offering a less energy-intensive and more environmentally benign alternative to current technologies, this innovation has the potential to accelerate progress across a suite of interconnected Sustainable Development Goals, most notably those related to clean water, clean energy, climate action, and the protection of marine life.

SDGs Addressed in the Article

SDG 6: Clean Water and Sanitation

• The core subject of the article is a new method for desalination, which is the process of converting saltwater into fresh, drinkable water. This directly addresses the global need for clean water, especially in regions facing water scarcity. The research aims to create a more efficient way to produce freshwater, contributing to the availability and sustainable management of water resources.

SDG 7: Affordable and Clean Energy

• The article highlights that the new desalination method is a “solar desalination” technique that “could reduce the need for energy-intensive saltwater treatment.” It contrasts this new approach with traditional methods like reverse osmosis, which have “heavy electricity demands.” By using solar energy (sunlight) and potentially bypassing energy-intensive thermal processes, this innovation promotes the use of clean, renewable energy and improves energy efficiency in the water sector.

SDG 9: Industry, Innovation, and Infrastructure

• The article is centered on a scientific “breakthrough” and “innovation” from UC Riverside researchers. It describes a novel technological approach using aluminum nitride and deep UV light for desalination. This focus on research, development, and the creation of new, more sustainable technologies aligns perfectly with the goal of fostering innovation and upgrading industrial processes to be more environmentally sound.

SDG 14: Life Below Water

• A key benefit of the proposed system, as mentioned in the article, is its potential to “address the concentrated reverse-osmosis brine waste, which is toxic to marine life when discharged into waterways.” By reducing or altering this harmful byproduct of traditional desalination, the innovation contributes to the prevention and reduction of marine pollution from land-based activities.

SDG 17: Partnerships for the Goals

• The article explicitly states that the research project is “supported through a range of research efforts and funding agencies, including the National Science Foundation, the Department of Education, and UCR seed funding.” This collaboration between a university, government agencies, and internal funding mechanisms exemplifies the multi-stakeholder partnerships needed to advance science and technology for sustainable development.

Specific SDG Targets Identified

Targets for SDG 6: Clean Water and Sanitation

1. Target 6.1: By 2030, achieve universal and equitable access to safe and affordable drinking water for all. The technology’s primary purpose is to produce freshwater from saltwater, directly contributing to increasing the supply of safe drinking water.
2. Target 6.4: By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity. Desalination is a key technology for addressing water scarcity, and making it more efficient contributes to a sustainable freshwater supply.

Targets for SDG 7: Affordable and Clean Energy

1. Target 7.2: By 2030, increase substantially the share of renewable energy in the global energy mix. The method is a form of “solar desalination,” relying on sunlight, a renewable energy source.
2. Target 7.3: By 2030, double the global rate of improvement in energy efficiency. The research aims to create a less “energy-intensive” alternative to current desalination methods, thus improving energy efficiency in water production.

Targets for SDG 9: Industry, Innovation, and Infrastructure

1. Target 9.4: By 2030, upgrade infrastructure and retrofit industries to make them sustainable, with increased resource-use efficiency and greater adoption of clean and environmentally sound technologies and industrial processes. The described method is a new, clean, and potentially more resource-efficient technology for the water industry.
2. Target 9.5: Enhance scientific research, upgrade the technological capabilities of industrial sectors…encouraging innovation. The entire article details a scientific research project that represents a technological advancement and encourages further innovation in the field.

Targets for SDG 14: Life Below Water

1. Target 14.1: By 2030, prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities. The technology’s potential to address the toxic brine waste from reverse osmosis directly contributes to reducing a harmful pollutant discharged into marine environments.

Targets for SDG 17: Partnerships for the Goals

1. Target 17.16: Enhance the global partnership for sustainable development, complemented by multi-stakeholder partnerships that mobilize and share knowledge, expertise, technology and financial resources. The collaboration between UC Riverside researchers and funding from the National Science Foundation and the Department of Education is a direct example of such a partnership to advance sustainable technology.

Indicators for Measuring Progress

Indicators Mentioned or Implied in the Article

• Evaporation rates of salt water: This is an explicitly mentioned indicator used in the research to measure the effectiveness of the new method. The article states, “Under UV light, evaporation rates of salt water increased significantly compared to control samples.”
• Energy efficiency of the desalination process: This is a strongly implied indicator. The article’s emphasis on reducing “heavy electricity demands” and creating a less “energy-intensive” process suggests that the energy consumed per volume of freshwater produced is a key metric for success.
• Reduction in toxic brine discharge: This is an implied indicator of environmental impact. The claim that the system could “address the concentrated reverse-osmosis brine waste” means that a measure of progress would be the reduction in the volume or toxicity of this waste product compared to traditional methods.
• Investment in research and development: This is an implied indicator of innovation. The mention of support from “the National Science Foundation, the Department of Education, and UCR seed funding” points to R&D expenditure as a measure of commitment to developing this sustainable technology.

Summary Table: SDGs, Targets, and Indicators

Source: news.ucr.edu