Biosynthesis and Application of Nanostructured Composites for Purification of Drinking Water: A Modification of the Solar Disinfection(SODIS)Technique

EPA Grant Number: SU839297
Title: Biosynthesis and Application of Nanostructured Composites for Purification of Drinking Water: A Modification of the Solar Disinfection(SODIS)Technique
Investigators: Obuya, Emilly
Institution: The Sage Colleges
EPA Project Officer: Page, Angela
Phase: I
Project Period: February 1, 2018 through January 31, 2019
Project Amount: $14,766
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2017) RFA Text |  Recipients Lists
Research Category: Sustainability , P3 Awards , P3 Challenge Area - Water


Silver nanoparticles (Ag NPs) will be biosynthesized from the rind extract of the watermelon fruit, and loaded on the surface of titanium dioxide nanofibers (TiO2 NFs) to generate a heterogeneous Ag-TiO2 photocatalyst. A wet synthesis method will be employed to optimize the surface and electronic properties of the nanocomposite material through an elaborate control of the size of the Ag NPs on the TiO2 surface. The disk diffusion method will be used as a quantitative antimicrobial assay of the heterogeneous Ag-TiO2, and its activity compared against homogeneous Ag NPs, and bare TiO2 NFs. These catalysts will then be used in lab simulations for the photo-inactivation studies to test their ability to utilize the visible portion of sunlight to remove E. coli from a drinking water sample. The use of the watermelon rind for synthesis of Ag NPs minimizes the need for chemicals by taking advantage of readily available raw materials. Nanomaterials have new and improved surface and electronic properties that require the use of small amounts of catalyst for maximum efficiency. This will increase the cost effectiveness of the process and ensure a sustainable adoption of the process to communities that need it. The semiconductor nature of the TiO2, coupled with the surface plasmon resonance of the Ag NPs will enable the use of the visible portion sunlight hence improving energy efficiency and overall sustainability of the technology. With successful implementation of this technology in Phase II, the SODIS device will improve water treatment and sanitation for the communities affected, thereby decreasing the incidences of waterborne diseases and ensuring prosperity for generations to come. This project will be used to teach the concepts of sustainability at the university level since water contamination is a huge problem that affects the entire community. For the implementation phase of this project to be successful, a plan will be rolled out to educate and train theĀ  ommunity on how to correctly use and sustain the SODIS device.


Solar disinfection (SODIS) technique has emerged within the past decade as a simple and low cost point-of-use water treatment technology. For bacterial inactivation, contaminated water is placed in clear plastic (PET) bottles and exposed to direct sunlight illumination for a period of 6 - 48 hours. This makes the process cumbersome and hampers large scale adoption. Additionally, the SODIS technique is incapable of removing chemical contaminants from the drinking water thus limiting its versatility. This project will apply green chemistry principles and nanotechnology to design, synthesize, and develop a heterogeneous nanocomposite that will be used as an additive to improve the overall efficiency of the SODIS technique.

Expected Results:

Ag NPs and TiO2 NFs both have reported antimicrobial activity against pathogenic bacteria but their combined effect in the SODIS method has not been studied. The combined effects of the nanomaterialsā€™ high surface area, visible-light activation, heterogeneous photocatalysis and nontoxicity is expected to shorten illumination times, generate highly reactive radicals that will eliminate bacteria without possibility of re-growth, and allow the decontamination of chemicals. Additionally, the heterogeneous nature of the Ag-TiO2catalyst will make it easy to remove from the drinking water and enable recyclability.

Supplemental Keywords:

Solar disinfection, water treatment and sanitation, TiO2 heterogeneous photocatalysis, silver nanoparticles