Chitosan Filter with Photocatalytic Self-Regeneration
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Solution Overview
Problem
Conventional filters lack self-regenerative capabilities, fixed pore sizes, and adjustable surface charge, making them inefficient for removing specific particulates, heavy metals, and organic pollutants from gases and liquids, and they require frequent replacement.
Innovation Solution
A chitosan-based filter medium with tunable porosity and surface charge, incorporating photocatalytic materials like titanium dioxide, zinc oxide, and manganese dioxide, and chitosan derivatives, which allows for manipulation of pore size and surface charge, and self-regeneration under light activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional filters are used, then they can remove contaminants, but they require frequent replacement and lack self-regenerative capability
Solution Approach 1:
The filter medium incorporates photocatalytic materials that enable self-regeneration by using light activation to decompose accumulated organic pollutants and restore the filter's contaminant removal capacity, eliminating the need for frequent replacements
Solution Approach 2:
The photocatalytic materials decompose and recover the filter medium's active sites by breaking down accumulated contaminants under light activation, restoring the filter's performance without requiring physical replacement
2Adaptability or versatility
If conventional filters are used, then they can filter particulates, but their pore size is fixed and cannot be manipulated to suit various particulates
Solution Approach 1:
The filter medium's pore size is manipulated by varying parameters such as biopolymer concentration, crosslinking density, amount of copolymers and additives, freezing speed and profile, and types of crosslinker used, enabling adjustment to suit different particulate sizes
Solution Approach 2:
The filter medium transitions from a fixed pore size structure to a dynamically adjustable pore structure through controlled crosslinking and freezing processes, allowing optimization for different filtration requirements
3Adaptability or versatility
If conventional filters are used, then they can remove contaminants, but they have fixed surface charge and cannot be tuned for specific applications
Solution Approach 1:
The surface charge of the filter medium is tuned by adding different agents to modify the surface and/or density of the chitosan, enabling optimization for removing specific charged contaminants
Solution Approach 2:
The filter medium incorporates regions with different surface charge characteristics through selective agent addition, creating localized areas optimized for attracting specific types of contaminants based on their charge properties
4Quantity of substance
If chitosan-based filter medium is used, then it has high contaminant adsorption capacity, but it lacks mechanical strength
Solution Approach 1:
The filter medium combines chitosan with crosslinking agents and potentially other polymers to create a composite structure that maintains high contaminant adsorption capacity while significantly improving mechanical strength through the crosslinked network
Solution Approach 2:
The mechanical strength is enhanced by controlling the crosslinking density and type of crosslinker used, allowing optimization of the balance between structural integrity and contaminant adsorption capacity
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 filter medium achieves high removal efficiency for bacteria, heavy metals, and organic pollutants, with self-regeneration capabilities extending its service life and improved mechanical strength, effectively removing over 99% of E. Coli, 98% of Cd, 78% of Pb, and 90% of organic pollutants like Allura red.
Implementation Method 1
incorporating an effective amount of photocatalytic materials such as metallic oxide including but not limited to titanium dioxide, zinc oxide, vanadium oxide, and manganese dioxide, which are in nanomized size, in order to restore the capacity of the filter medium effectively under light activation of certain wavelength while the photocatalytic materials can also decompose organic pollutants accumulated on the medium
Implementation Method 2
Chitosan, a polycationic biopolymer of (1-4)-linked 2-amino-2deoxy-D-glucopyranose, is an abundant natural polysaccharide, which is well known for the superb capacity to adsorb contaminants and heavy metals
Implementation Method 3
The crosslinker used for crosslinking chitosan to form said crosslinked chitosan derivatives includes but not limited to Trisodium citrate dihydrate, sodium hydroxide, tripolyphosphate (TPP), glyoxal, glutaraldehyde
Implementation Method 4
Freezing temperature is also critical to the morphology and pore size of the present filter medium. Said freezing temperature can be from −10° C. to −55° C.
Data Source
AI summary
A self-regenerating chitosan based filter medium for disinfecting and purifying organic pollutants and other pollutants in a gas or liquid is disclosed herein. Porosity and surface charge of said filter medium is manipulative/tunable by varying one or more of the following parameter(s): concentration of chitosan, crosslinking density, amount of copolymers and additives, freezing temperature, freezing profile, and/or types of crosslinker used. The present filter medium is capable of self-regenerating under exposure to ultra-violet light for sufficient time and removing over 90% of the pollutants from each influent flowing through the filter medium.