TiO2-Silver Water Purification Coating With Minimal Leaching
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Solution Overview
Problem
Existing water purification methods are costly, time-consuming, and inefficient in removing contaminants like bacteria, algae, and fungi, and they often require expensive apparatus or lead to the leaching of nanomaterials into treated water, compromising their effectiveness.
Innovation Solution
A composite material comprising a titanium dioxide nanotube layer loaded with silver nanoparticles is bonded to a substrate using aerosol deposition at controlled temperatures, ensuring minimal leaching and maintaining efficiency by preserving the nanocomposite's chemical structure and configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional water purification methods (activated carbon, halogens, etc.) are used, then water can be treated, but they either insufficiently remove contaminants, require extended time, or are costly and time-consuming
Solution Approach 1:
The patent uses a composite material combining titanium dioxide nanotubes and silver nanoparticles to achieve both high contaminant removal efficiency and rapid action. The composite structure allows TiO2 to provide photocatalytic activity while silver nanoparticles enhance antibacterial properties, creating a synergistic effect that outperforms individual materials in both efficiency and speed.
Solution Approach 2:
The titanium dioxide is structured as nanotubes with porous architecture, which increases the surface area available for contaminant interaction. This porous structure allows better contact between the purification agent and water contaminants, enhancing removal efficiency while maintaining rapid action through increased reactive surface area.
2Reliability
If halogens are used as antibacterial agents, then antibacterial effect is achieved, but high toxicity and high vapour pressure cause disadvantages
Solution Approach 1:
The patent changes the physical and chemical parameters of the antibacterial agent from bulk halogen (high toxicity, high vapour pressure) to nanoscale silver particles (low toxicity, negligible vapour pressure). This parameter change at the nanoscale maintains antibacterial effectiveness while eliminating harmful properties.
Solution Approach 2:
The silver nanoparticles serve as a safer, more sustainable alternative to halogens. While silver has cost implications, it eliminates the safety hazards and environmental concerns associated with halogen toxicity and vapour pressure, making it suitable for continuous use without the harmful side effects.
3Ease of manufacture
If activated carbon is used, then water filtration is achieved, but it insufficiently removes bacteria, algae and fungi
Solution Approach 1:
The patent changes the purification mechanism from physical adsorption (activated carbon) to photocatalytic and antimicrobial action (TiO2 nanotubes with silver nanoparticles). This parameter change in the fundamental mechanism enables effective removal of biological contaminants that activated carbon cannot adequately address.
Solution Approach 2:
The composite of TiO2 and silver nanoparticles provides dual functionality: TiO2 photocatalysis breaks down organic contaminants while silver nanoparticles directly kill bacteria, algae, and fungi through contact and ion release, achieving comprehensive biological contaminant removal that single materials cannot provide.
4Ease of manufacture
If dip coating technique is used to create TiO2 thin film, then coating is formed, but the bond between substrate and nanoparticles is insufficient causing leaching
Solution Approach 1:
The patent employs aerosol deposition where the coating material is delivered as an aerosol (liquid/gas phase) that deposits and bonds to the substrate. The phase transition from aerosol to solid film creates strong adhesion, preventing nanoparticle leaching while maintaining ease of manufacture through the spray application process.
Solution Approach 2:
The patent replaces the mechanical dip coating process with aerosol deposition. This substitution creates superior bonding between nanoparticles and substrate through the deposition mechanism, eliminating the leaching problem associated with dip coating while maintaining manufacturing simplicity.
5Reliability
If nanomaterial particles are used for water treatment, then purification efficiency is improved, but particles leach into water compromising effectiveness
Solution Approach 1:
The titanium dioxide nanotube structure provides a porous framework that anchors silver nanoparticles firmly in place. This porous architecture maintains high purification efficiency through increased surface area while the structured framework prevents nanoparticle detachment and leaching into the water.
Solution Approach 2:
The composite structure of TiO2 nanotubes supporting silver nanoparticles creates a stable architecture where the nanotube framework provides structural integrity and prevents leaching, while the silver nanoparticles maintain their purification function. The composite nature ensures both high efficiency and minimal leaching.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composite material effectively reduces bacterial contaminants in water with minimal leaching, achieving up to 99% reduction within 60 minutes and maintaining efficiency over multiple cycles.
Implementation Method 1
wherein the substrate is heated to a temperature of from 100 °C to 500 °C, preferably from 150 °C to 300 °C, more preferably to a temperate of 250 °C, thereby depositing the active layer onto the substrate
Implementation Method 2
aerosolizing the active layer solution and directing the aerosol towards a heated substrate, wherein the substrate is heated to a temperature of from 100 °C to 500 °C, preferably from 150 °C to 300 °C, more preferably to a temperate of 250 °C, thereby depositing the active layer onto the substrate
Implementation Method 3
The invention further relates to the use of the composite material for reducing contaminants in water
Data Source
Figure 1a~1b
Figure 2a~3a
Figure 3b~3c
AI summary
The invention relates to a composite material, suitable for treating water. The composite material comprises an active layer and a substrate layer, with the active layer including titanium dioxide and silver nanoparticles. The active layer is bonded to the substrate layer such that, in use, there is substantially no leaching of the active layer into the body of water. The invention further relates to a method of preparing the composite material.