Macroporous TiO2 Photocatalyst via Electrolytic Discharge Oxidation

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Solution Overview

Problem

Conventional TiO2 photocatalysis for wastewater treatment faces limitations due to low efficiency of light use, difficulty in stirring and separation, and low surface area, which restricts its effectiveness in industrial applications, and microbial fuel cells are hindered by high capital costs, limited COD reduction, and scalability issues.

Innovation Solution

A high surface area TiO2 photocatalyst is manufactured using electrolytic discharge oxidation, forming a macroporous titanium dioxide structure with a high proportion of the anatase phase, integrated into a microbial fuel cell design that combines photocatalytic and microbial treatment, enabling efficient photocatalytic oxidation and proton transfer without mediators or proton exchange membranes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional TiO2 photocatalysis is used for wastewater treatment, then the treatment process can be implemented, but the efficiency is limited due to low surface area and low light utilization

Engineering Contradiction:
Improvephotocatalytic activityVSAvoidsurface area of photocatalyst
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent applies porous materials by forming a macroporous titanium dioxide structure through electrolytic discharge oxidation. The process creates a highly porous coating with large internal surface area on titanium substrates, which dramatically increases the photocatalytic active sites available for wastewater treatment while maintaining structural integrity.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent transforms the photocatalyst from a conventional flat or granular form to a three-dimensional macroporous structure. This dimensional transformation creates extensive internal surfaces and channels that increase light scattering paths and provide numerous reaction sites, thereby enhancing photocatalytic efficiency without increasing the physical footprint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If conventional TiO2 photocatalysis is used, then treatment can proceed, but light penetration is limited in turbid waste streams

Engineering Contradiction:
Improvephotocatalytic treatment efficiencyVSAvoidUV light penetration
Core Design Contradiction:
ProductivityVSIllumination intensity

Solution Approach 1:

The macroporous structure acts as a light-trapping architecture that increases the optical path length within the photocatalyst layer. Light enters the porous structure and undergoes multiple internal reflections and scatterings, significantly extending its path length and interaction time with TiO2 surfaces even in turbid conditions, thereby enhancing photocatalytic effectiveness.

Inventive Principle:
Principle #31Porous materials

3Productivity

If microbial fuel cells are used for wastewater treatment, then energy recovery is possible, but capital costs are high due to proton exchange membranes and mediators

Engineering Contradiction:
Improveenergy recovery capabilityVSAvoidcapital cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the expensive proton exchange membrane component from the microbial fuel cell system. By using a photocatalytic anode that directly generates protons through photocatalytic oxidation, the system removes the need for PEMs and chemical mediators, dramatically reducing capital costs while maintaining energy recovery functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The photocatalytic anode performs self-service by generating its own protons through photocatalytic water oxidation. This eliminates the need for external proton sources or complex proton transfer mechanisms through membranes, simplifying the system architecture and reducing costs associated with PEMs and mediators.

Inventive Principle:
Principle #25Self-service

4Productivity

If conventional photocatalysis with stirring is used, then treatment efficiency is limited by difficulty in stirring and separation

Engineering Contradiction:
Improvetreatment efficiencyVSAvoidstirring and separation operation
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The photocatalyst is pre-formed as a rigid macroporous coating on a titanium substrate before deployment. This preliminary structuring eliminates the need for continuous stirring to maintain suspension, as the coated substrate can be easily positioned and will remain stable in the wastewater stream, simplifying operation and facilitating separation by simple removal.

Inventive Principle:
Principle #10Preliminary action

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

This approach enhances photocatalytic activity, increases COD reduction, and allows for scalable and cost-effective wastewater treatment, overcoming limitations of conventional systems by providing a flexible and efficient photocatalyst structure that integrates well with microbial fuel cells, enabling effective treatment of industrial wastewater.

Implementation Method 1

A high surface area TiO2 photocatalyst formed by electrolytic discharge oxidation (EDO) of a substrate comprising titanium

Methodology Applied
Scientific EffectElectrolytic discharge oxidation: Electrolysis

Implementation Method 2

forming a macroporous titanium dioxide structure with a high proportion of the anatase phase

Methodology Applied
Scientific EffectAnodising: Anodising

Implementation Method 3

an electron is excited by absorbing a photon (UV light) there remains a positive charge (a hole) in the valence band

Methodology Applied
Scientific EffectPhotoabsorption: Absorption (EM radiation)

Implementation Method 4

the electronically excited catalyst, TiO2 forms electron (-) and hole (+) pairs and has been shown to oxidize and reduce many organic molecules

Methodology Applied
Scientific EffectPhotocatalysis: Catalysis

Implementation Method 5

forming a macroporous titanium dioxide structure with a high proportion of the anatase phase

Methodology Applied
Scientific EffectPorosity: Porosity

Data Source

PatentEP2830757B1Method of manufacturing a photocatalyst
Publication Date: 2021.01.20 KERONITE INTERNATIONAL LIMITED
  • EP2830757B1 patent drawingFigure 1
  • EP2830757B1 patent drawingFigure 2
  • EP2830757B1 patent drawingFigure 3

AI summary

The present invention relates to a photocatalyst and a method of manufacturing a photocatalyst. More specifically, the present invention relates to a high surface area TiO 2 photocatalyst formed by electrolytic discharge oxidation (EDO) of a substrate comprising titanium. A flexible high surface area photocatalyst architecture comprising a compliant, cohesive, well-adhered and highly porous surface layer of the anatase phase of titanium dioxideis provided. The highly porous surface layer of the anatase phase of titanium dioxideisformed in a single step by the electrolytic oxidation of a titanium surface on a permeable, flexible, and electrically conductive substrate sponge structure.