FeS-Based pH-Responsive Material for Copper Recovery from Micro-Etching Wastewater
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Solution Overview
Problem
Existing methods for treating copper-containing wastewater from micro-etching face challenges such as difficult deep purification, low recycling rate, and high recycling cost due to the stability and toxicity of the wastewater, as well as the complexation of copper ions with organic and inorganic substances.
Innovation Solution
A method utilizing a FeS-based pH-responsive material (CMC-FeS@HS #SiO2 #COOH) that slowly releases HS− and provides abundant surface active sites, allowing for efficient precipitation of Cu(II) by adjusting the pH value of the wastewater, thereby facilitating the recycling of copper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional treatment processes (chemical precipitation, oxidation reduction, adsorption, membrane separation, ion exchange) are used to remove heavy metals from wastewater, then heavy metal removal is achieved, but the treatment effect for heavy metal complex-containing wastewater is inferior due to the complexation of metal ions with refractory organic ligands
Solution Approach 1:
The patent changes the chemical environment parameters by adjusting pH to weakly acidic conditions (pH 3-6), which alters the speciation and reactivity of copper ions and organic ligands. This parameter change disrupts the stable metal-organic complexes, making copper ions more available for precipitation and significantly improving removal efficiency from 60-80% to over 95%.
Solution Approach 2:
The patent introduces FeS-based pH-responsive materials as intermediary substances that mediate the removal process. These materials serve dual functions: (1) they buffer and maintain weakly acidic pH conditions that destabilize metal complexes, and (2) they provide sulfide ions for selective precipitation of copper. This intermediary approach overcomes the limitation of conventional methods that cannot effectively break stable complexes.
2Reliability
If inorganic sulfide precipitants (sodium sulfide, calcium polysulfide, ferrous sulfide, hydrogen sulfide) are used under acidic conditions to produce sulfide precipitates, then copper removal is achieved, but toxic hydrogen sulfide gas is generated and precipitated particles are fine and difficult to filter
Solution Approach 1:
The patent converts the harmful effect of acidification (which would normally cause H2S gas release from sulfide precipitants) into a beneficial effect. By using FeS-based pH-responsive materials, the acidification is controlled to selectively destabilize metal complexes while the FeS matrix prevents uncontrolled H2S generation. The pH-responsive release of sulfide ions ensures copper precipitation without excessive toxic gas emission, turning the potential harm into a controlled beneficial process.
Solution Approach 2:
The patent employs composite FeS-based materials that combine iron sulfide with pH-responsive components. This composite structure provides controlled sulfide ion release at specific pH ranges, enabling selective copper precipitation while minimizing H2S gas generation. The composite nature also improves particle morphology and filterability compared to conventional inorganic sulfide precipitants, solving both the toxic gas and filtration problems simultaneously.
3Object-affected harmful factors
If heavy metal ions are removed from copper-containing wastewater, then environmental pollution is reduced, but the recycling rate and resource recovery are low due to the stability and toxicity of the wastewater
Solution Approach 1:
The patent selectively extracts copper ions from complex wastewater matrices by creating conditions that destabilize metal-organic complexes and promote selective copper sulfide precipitation. The FeS-based pH-responsive materials enable copper to be 'taken out' from stable complexes and precipitated as CuS, achieving over 95% recovery rate. This extraction approach simultaneously reduces environmental pollution and recovers valuable copper resources, resolving the contradiction between pollution control and resource recovery.
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 method achieves a copper ion recovery rate of 99.8% or more, enhances the precipitation efficiency of copper ions, and allows for the deep removal of copper ions from the solution, while also reducing environmental pollution and treatment costs.
Implementation Method 1
adding a FeS-based pH-responsive material to weakly-acidic copper-containing wastewater from micro-etching, to allow a reaction I to obtain a precipitate with CuS as a main component
Implementation Method 2
allows for efficient precipitation of Cu(II) by adjusting the pH value of the wastewater
Implementation Method 3
provides abundant surface active sites, allowing for efficient precipitation of Cu(II)
Data Source
AI summary
A method for recycling a copper-containing wastewater from a micro-etching is provided, including: modifying a FeS material with a monomer including both carboxyl and sulfhydryl, a crosslinking agent, and a stabilizing and dispersing agent to obtain a FeS-based pH-responsive material CMC-FeS@HS #SiO2 #COOH, adding the FeS-based pH-responsive material to weakly-acidic copper-containing wastewater from the micro-etching to allow a reaction, and conducting processes such as sulfide precipitation, exchange, adsorption complexation, and flocculation precipitation to finally obtain a precipitate with CuS as a main component. This method makes full use of the pH responsiveness and abundant surface active sites of the FeS-based pH-responsive material, and can control a recovery rate of copper ions in the wastewater at 99.8% or more merely by adjusting a pH value of the copper-containing wastewater from the micro-etching.