Tio2 composite photocatalytic disinfection system for home water treatment
A visible-light-activated photocatalytic disinfection system using a TiO2/Ag3PO4 composite in an upflow photoreactor for household water treatment. The technology targets microbial inactivation and trace organic contaminant removal, offering an energy-efficient alternative to conventional UV-based water purification systems.
Overview
This research proposes a visible-light-activated photocatalytic disinfection system designed for household water treatment. The technology addresses limitations of conventional UV-based systems by using a composite photocatalyst that operates under visible light, significantly reducing energy requirements. The system builds on prior validated work with TiO2-coated quartz in an upflow photoreactor under UVC light, extending the approach by coupling TiO2 with a narrow-bandgap semiconductor (Ag3PO4) to enable visible-light-driven photocatalysis. The composite targets both microbial inactivation and degradation of trace organic contaminants in water.
Technical specifications
Key features:
- Composite photocatalyst: TiO2 coupled with Ag3PO4, a narrow-bandgap semiconductor, forming heterogeneous junctions that improve electron-hole pair separation
- Visible-light activation: The composite enables photocatalytic activity under visible light, unlike TiO2 alone which requires UVC due to its wider bandgap
- Upflow photoreactor design: A uniquely designed reactor with 50% fluidization of the catalyst bed, preventing catalyst loss and maintaining stable activity with repeated use
- Supported catalyst: The composite is supported on quartz or microbeads to enhance stability and prevent loss of Ag3PO4, which is unstable in unsupported form
- Dual functionality: Effective for microbial inactivation and photodegradation of trace organic contaminants in water
- Energy efficiency: Prior UVC validation showed electric energy per order (EEO) reduction from approximately 1.6 kWh/m³-order to 0.25 kWh/m³-order with optimized catalyst-peroxide combinations
Validation approach:
- Microbial inactivation testing using overnight bacterial cultures of Pseudomonas aeruginosa (ATCC 15442) and Staphylococcus aureus (ATCC 6538)
- Spiked test water evaluated at different flow rates to assess efficacy across varying contact times
- Influent and effluent samples analyzed on selective agar using spread plate methods
- Homogeneous mixing ensured by injecting cultures through the inlet port
Technology readiness level
The technology is at an early-to-mid stage of development. Preliminary validation has been completed for the TiO2-coated quartz system under UVC light, demonstrating higher photoactivity and energy efficiency compared to UV/H2O2 alone at similar UV doses. The current research phase focuses on adapting the validated upflow photoreactor platform to operate under visible light using the new Ag3PO4/TiO2 composite photocatalyst. Future work includes systematic evaluation of disinfection efficacy against representative bacterial targets at varying flow rates and contact times, with the goal of developing a household-scale disinfection system.
About Arizona State University
Arizona State University is a comprehensive public research university with a multi-campus presence across the Phoenix metropolitan area and a scale that supports interdisciplinary, use-inspired discovery. Industry partners access co-located laboratories, a research and technology park, and innovation centers that house corporate teams with faculty to speed prototyping and validation. A formal alliance with a major hospital system and proximity to a fast-growing manufacturing corridor enable clinical translation and pilot-scale testbeds, while applied student engagements create dependable talent pipelines. Research is backed by competitive federal funding from agencies such as NSF, NIH, DOE, DOD, and NASA. A dedicated technology transfer office supports IP, licensing, and startup formation.
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