Grantee Research Project Results

Final Report: Desalination using 2D MoS2 Nano-solar Evaporator

EPA Grant Number: SU840162
Title: Desalination using 2D MoS2 Nano-solar Evaporator
Investigators: Lee, Woo Hyoung , Hwang, Jae-Hoon , Jung, Yeonwoong , Stoll, Stephanie , Watson-Bajorek, Amaya , Osorto, Brando , Yoo, Changhyeon , Han, Sang Sub
Institution: University of Central Florida
EPA Project Officer: Spatz, Kyle
Phase: I
Project Period: December 1, 2020 through November 30, 2021
Project Amount: $25,000
RFA: P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet (2020) RFA Text |  Recipients Lists
Research Category: P3 Awards , P3 Challenge Area - Safe and Sustainable Water Resources

Objective:

Water scarcity is increasing at alarming rates all over the globe causing a raise in questions regarding the sustainability of freshwater supplies. A combination of various methods including water management and reduced water consumption, domestic and industrial wastewater treatment and desalination of saltwater is currently being used to cope with this problem. Although there is more than enough available saltwater on earth to compensate for the freshwater scarcity, current desalination technologies, such as reverse osmosis (RO) membrane processes are physically and economically limited. The overall goal of this project is to improve the efficiency of solar light thermal evaporation and desalination through a biomimicry application of the new photothermal nanomaterial (MoS2). The research objectives of this study are to: (1) develop a 2D MoS2 layer-based solar evaporator for water evaporation; (2) evaluate thermal evaporation performance of a 2D MoS2 layer-based solar evaporator; and (3) analyze a lab-scale solar-water desalination system for clean water production. Unlike other metal oxides (e.g., TiO2) used for traditional photo-thermal conversion systems, 2D MoS2 layers are ideally suitable for photo thermal conversion as their band gap energy highly tunable through 2D layer structure modification to match the visible light range for a broader range of light.    
A novel solar evaporator based on innovative 2D MoS2 nanomaterials is proposed to positively impact the planet in a tremendous way by utilizing two abundant renewable resources, seawater and sunlight, and offering an alternative to rapid aquifer depletion, which is an increasing issue as population density grows. Rapid consumption of groundwater causes aquifer depletion or saltwater intrusion, such as in the southeastern regions of the U.S. The 2D MoS2 layer-based solar evaporator can also be used by local water treatment plants that are located near oceans or in areas that experience an abundance of droughts, such as arid or semi-arid regions in the West. The system will be able to provide fresh water to local farms and public facilities. The positive impact on people encompasses the security in, and health benefits from, a secure, dependable, and safely managed water service. During the implementation of the research project, community approval will be sought in order to maximize economic benefits (prosperity) through urban development in the surrounding area. Overall, this novel method of solar evaporation-driven water desalination will provide a unique and sustainable solution for accessible drinking water and smart irrigation. In addition, this research has the potential to inform those in academia and in the community about the innovative approach to the design and necessity of compact and simple desalination processes with low energy input. A presentation of the results of this P3 project will be addressed and shared with UCF's chapter of Engineers without Borders (EWB) and Society of Environmental Engineers (SEE), which will also be open to the rest of the community. 

Summary/Accomplishments (Outputs/Outcomes):

Results from this project successfully displayed a simple and cost-effective desalinization process for water production. First, 2D MoS2-embedded sponges were developed by utilizing a 3D printed water-soluble polyvinyl alcohol (PVA) template. A mixture of 10% wt. of MoS2 and ClearFlex 50 (Urethane Rubber (PU)) was poured into the template and allowed to cure. After 48 hours, the sponge was placed in DI and the PVA scaffold fully dissolved after 48 hours. It was found that the approximate cost of the development of a single sponge is around $0.70-0.80. Second, the photo-thermal properties of the MoS2-PU sponge were tested by illuminating the sponge under simulated sunlight of 790 W/m2. The tested samples reached an average temperature of 60°C and the top side of the sponge, with the direct light, reached a temperature of 70.8°C. The MoS2-PU sponge was then tested in the natural sunlight environment (1,343 W/m2) and the sponge reached a maximum temperature of 73.4°C. Finally, simulation tests of the MoS2-PU sponge were conducted in the lab under the simulated sunlight using DI water as well as and outside the lab using seawater. The results of the test showed that the MoS2-PU sponge successfully evaporated 100 mg of DI water in 40 minutes, compared to a PU-sponge (No MoS2 coating) which took 60 minutes. The MoS2-PU sponge was then tested in a miniature greenhouse in the natural sunlight using simulated seawater (35% wt. saltwater). The results of the test showed an evaporation rate of 23.6 mg/min for the MoS2-PU sponge, compared to 13.6 mg/min with the PU-sponge, and 7.2 mg/min of just the water. The evaporation performance of the sponge was evaluated with the DI water under simulated sunlight and the simulated seawater under natural sunlight resulting in an efficiency of 0.298 and 2.14, respectively. The simulation test results showed the great potential of the developed 2D MoS2 layer-based solar evaporator for a reliable and suitable desalinization process using seawater. 

Conclusions:

Water scarcity is an emerging issue due to an exponentially increasing population and the overutilization of freshwater resources. For these reasons, methods of desalination have become increasingly more popular since approximately 68% of the world is cover by the ocean. However, current methods of desalination are energy-intensive, do not produce a sustainable amount of water, and produce a brin discharge that is potentially harmful to the surrounding environment. We expect that the developed 2D MoS2 nano-solar evaporator will provide a more cost-effective and sustainable process for desalination for arid or coastal communities. Through the objectives outlined in Phase I, we have demonstrated the successful development and characterization of the MoS2-based solar thermal desalination system. Through the various tests conducted, the addition of the MoS2 sponge proves to be a valuable addition in effectively increasing the evaporation of both DI water and saltwater. Encouraged by the successful proof-of-concept demonstrated in the Phase I period, we will extend our works with the following tasks proposed in Phase II. 

Journal Articles on this Report : 1 Displayed | Download in RIS Format

Publications Views

Other project views:	All 1 publications	1 publications in selected types	All 1 journal articles

Publications

Type	Citation	Project	Document Sources
Journal Article	Yoo C, Ko TJ, Hwang JH, Mofid SA, Stoll S, Osorto B, Morillo L, Han SS, Rodriguez KL, Lundin JG, Lee WH. 2D MoS2-polyurethane sponge for solar-to-thermal energy conversion in environmental applications:Crude oil recovery and seawater desalination. Journal of Water Process Engineering 2022;47:102665.	SU840162 (Final) SV839489 (Final)	Full-text: Science Direct- Full Text HTML Exit

Supplemental Keywords:

Desalination, MoS2, irrigation, solar evaporation, biomimicry, water resources, water treatment, water purification 

Relevant Websites:

Microsensor Biofilm Research Laboratory Exit , Jung Research Group Exit