Bituminous Membrane Depolluting Facing with TiO2 Granules
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Solution Overview
Problem
Current air depolluting technologies for buildings, such as those using titanium dioxide, often require complex concrete matrices and neutralization processes, which are not simple or efficient for widespread application on roofing and facing surfaces.
Innovation Solution
A bituminous membrane-based air depolluting facing with granules comprising at least 50% anatase titanium dioxide, which acts as a photocatalyst to oxidize NOx and SOx pollutants under UV light, with the oxidized products washed away by rainfall or sprinkling, eliminating the need for neutralization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a concrete matrix with titanium dioxide is used for air depollution, then the photocatalytic removal of NOx and SOx is achieved, but the device complexity and manufacturing complexity increase
Solution Approach 1:
The patent extracts the titanium dioxide photocatalyst from the complex concrete matrix and places it on a simple bituminous membrane substrate. This separation allows the photocatalyst to function independently without requiring the complex neutralization chemistry of concrete, thereby reducing device complexity while maintaining depollution effectiveness.
Solution Approach 2:
The patent uses a simple bituminous membrane as the substrate instead of durable concrete. This membrane is inexpensive, easy to apply, and can be replaced if needed, simplifying the overall system while maintaining the photocatalytic function through the titanium dioxide granules applied on top.
2Object-affected harmful factors
If a concrete matrix with calcium carbonate is used for neutralization, then the acidic intermediate products are neutralized, but the manufacturing precision and ease of manufacture decrease
Solution Approach 1:
The patent removes the calcium carbonate neutralization component from the system. Instead of using concrete that requires neutralization chemistry, the invention uses a bituminous membrane with titanium dioxide granules that directly oxidize pollutants to soluble salts that are washed away by rain, eliminating the need for complex neutralization manufacturing processes.
Solution Approach 2:
The patent simplifies the concrete-based neutralization process into a direct oxidation system. Rather than copying the complex concrete chemistry, it uses a simpler bituminous membrane substrate with titanium dioxide that achieves the same depollution effect through a different, easier-to-manufacture mechanism.
3Ease of manufacture
If titanium dioxide granules are applied on bituminous membrane, then the ease of manufacture and integration improve, but the stability of the object's composition may be compromised
Solution Approach 1:
The patent optimizes the size and surface area of the titanium dioxide granules to ensure stable adhesion to the bituminous membrane while maintaining photocatalytic effectiveness. The granules are sized to create sufficient surface contact with the membrane for stable attachment, yet remain large enough to maintain their photocatalytic function and resist degradation over time.
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 solution achieves a high efficiency in removing NOx and NO2 pollutants, with depollution rates of 2.3 g/m²/year and 0.6 g/m²/year respectively, while being easy to manufacture, handle, and integrate into existing roofing materials, maintaining efficiency even after aging.
Implementation Method 1
titanium dioxide, or TiO2, particularly in the anatase form, under the exposure of UV light, exhibit excellent photocatalytic properties in removing NOx and other pollutants from the air
Implementation Method 2
As TiO2 is exposed to UV light, it becomes increasingly hydrophilic
Implementation Method 3
the final products, soluble calcium nitrate or sulphate are washed away, either by rainfall or by sprinkling
Data Source
Figure 1~2
Figure 3~4
AI summary
A depolluting facing for a building structure, e.g. a roofing membrane, including a first and a second layer. The first layer 3 acting as base for the at least second layer 2 wherein the second layer consists of granules 2 comprising NOx reducing anatase titanium dioxide. The first layer may constitute a bituminous membrane or a panel made up from plastic or metal. The granules may be fixed to the roofing membrane by pressing or calendering on the hot bituminous blend embedding the granules in the bituminous membrane. The granules can be made of anatase titanium dioxide and a mineral binder, for example silicate or phosphate.