Decolorizing Colored Effluent via pH-Controlled Metal Salt Precipitation
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Solution Overview
Problem
Current methods for decolorizing colored effluents require large amounts of inorganic metal salts and polymer coagulants, leading to increased contamination and waste, and are ineffective due to re-dissolution of colored materials by chelating agents, making it difficult to achieve nearly colorless water.
Innovation Solution
Regulating the pH of colored effluents to prevent dissociation of polyvalent carboxylic or aminocarboxylic acid groups, allowing inorganic metal salts to form stable coagulants that effectively precipitate and remove colored materials without excessive chemical usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic coagulants are added to colored effluent containing chelating agents, then colored materials are initially captured, but colored materials are re-dissolved due to chelating agent effects
Solution Approach 1:
The patent applies preliminary action by adjusting the pH of the effluent to a specific range (pH 2-4) before adding inorganic coagulants. This pre-adjustment prevents chelating agents from re-dissolving the colored materials by ensuring the metal ions remain precipitated throughout the process, thereby maintaining the stability of the precipitation and improving decolorization effectiveness.
2Quantity of substance
If a large amount of inorganic metal salts and polymer coagulants are added to colored effluent, then colored materials are removed, but contamination and waste increase
Solution Approach 1:
The patent applies parameter changes by optimizing the pH parameter to a specific range (pH 2-4) and controlling the dosage of inorganic metal salts within a specific concentration range (100-2000 ppm). These parameter optimizations enable effective colored material removal while minimizing the amounts of chemicals required, thereby reducing chemical contamination and waste generation.
3Quantity of substance
If polymer coagulants are used to form separation coagulants with colored materials, then some decolorization is achieved, but nearly colorless water cannot be produced
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pH to a specific range (pH 2-4) and optimizing the dosage of inorganic metal salts. These parameter optimizations enable the formation of effective separation coagulants that can remove colored materials to produce nearly colorless water with a degree of coloration of at most 10, significantly improving the decolorization precision.
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 method allows for efficient decolorization of colored effluents at a lower cost, reducing contamination and waste, and achieving a degree of coloration of at most 10, making the treated water suitable for reuse.
Implementation Method 1
adding an inorganic metal salt to the colored effluent so as to allow the inorganic metal salt to react with the colored substance to form a precipitation in the colored effluent
Implementation Method 2
controlling a hydrogen ion exponent (pH) of the colored effluent to be in a range in which two or more carboxylic acid groups in the polyvalent carboxylic acid or the polyvalent aminocarboxylic acid does not dissociate
Data Source
AI summary
A method of decolorizing a colored effluent comprising (i) a colored substance; and (ii) a polyvalent carboxylic acid or a polyvalent aminocarboxylic acid, the method including the steps of: (a) controlling a hydrogen ion exponent (pH) of the colored effluent to be in a range in which two or more carboxylic acid groups in the polyvalent carboxylic acid or the polyvalent aminocarboxylic acid does not dissociate; (b) adding an inorganic metal salt to the colored effluent so as to allow the inorganic metal salt to react with the colored substance to form a precipitation in the colored effluent, and (c) eliminating the precipitation from the colored effluent.