Membrane Filter Deoxycholic Acid Surfactant Microorganism Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional membrane filters face challenges in maintaining precise pore size standards and achieving high recovery rates of microorganisms due to surfactant residues interfering with microbial growth and inadequate pore size for retaining small microorganisms like bacteria and mould spores.
Innovation Solution
The use of deoxycholic acid as a surfactant during membrane filter manufacturing, with a salt residue that minimizes interference with microbial growth, and orienting the air side facing the sample fluid to enhance microorganism retention, resulting in a recovery rate of 90% or better, along with a composition of cellulose acetate and cellulose nitrate and a grid pattern on the air side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional surfactant (sodium alkyl sulfonate) is used in the casting mix to ensure consistent filter quality and precise pore size, then manufacturing precision is improved, but the surfactant residue interferes with microbial growth, reducing recovery rate
Solution Approach 1:
The patent changes the chemical parameter of the surfactant from sodium alkyl sulfonate to deoxycholic acid. This parameter change maintains the surfactant's function in producing consistent pore sizes while its salt residue (deoxycholate) has minimal interference with microbial growth, thereby resolving the contradiction between manufacturing precision and recovery rate
Solution Approach 2:
The patent converts the previously harmful surfactant residue into a beneficial or neutral substance. Deoxycholic acid salt residue, while still present in the filter, does not significantly inhibit microbial growth unlike conventional surfactants. This transforms the harmful effect into an acceptable condition, maintaining both filter quality and high recovery rates
2Reliability
If the pore size is reduced to retain small microorganisms like bacteria and mould spores, then microorganism retention is improved, but fluid flow through the filter decreases
Solution Approach 1:
The patent applies local quality by orienting the air side of the membrane (which has optimal pore structure for retention) toward the sample fluid. This localized optimization allows the filter to achieve high retention of small microorganisms while maintaining adequate fluid flow, as the air side's structural characteristics are strategically positioned to face the fluid stream
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 deoxycholic acid surfactant and air-side orientation improve microorganism recovery rates significantly, achieving a 90% or better recovery rate and maintaining filter quality by reducing surfactant residue impact on microbial growth.
Implementation Method 1
The use of deoxycholic acid as a surfactant during membrane filter manufacturing, with a salt residue that minimizes interference with microbial growth
Implementation Method 2
filtering a sample of the liquid to be analysed, optionally using differential pressure across the filter, to retain any microorganisms in the filter
Implementation Method 3
The nutrient medium stimulates the growth of any microorganisms present on the filter. After the predetermined time, any microorganisms caught in the filter should have grown into colonies which are visible to the naked eye
Data Source
Figure 1~2
AI summary
A membrane filter 26 is disclosed comprising cellulous material 23 allowing the transition of fluid therethrough, and, in a substantially dry state, said membrane comprising also a salt of deoxycholic acid. Optionally, the air side of the membrane (the side facing away from the screen or belt used to manufacture the membrane) faces the sample fluid during use of the membrane. A method of manufacture of the membrane material is disclosed also, employing deoxycholic acid as a surfactant, to improve the recovery rate of the membrane filter in use.