Anion Adsorbent Selective Removal via Layered Stack Structure
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Solution Overview
Problem
Existing methods for removing toxic anions from wastewater are inefficient, as they often remove both anions and cations, require complex processes, impose spatial constraints, and are not environmentally friendly, with limited pH applicability and reversible adsorption.
Innovation Solution
A method involving the preparation of an anion adsorbent by mixing metal salts to form a stack structure with cationic and anionic layers, followed by heat treatments to remove water of crystallization and control the number of remaining anions, creating a structure with increased specific surface area for selective anion adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If porous adsorbent is used to remove toxic substances from wastewater, then adsorption capacity is improved, but selectivity deteriorates because cations are also removed in addition to toxic anions
Solution Approach 1:
The patent applies local quality by creating cationic layers with specific positive charges that are localized in certain regions of the adsorbent structure. This allows the material to selectively attract and adsorb toxic anions in specific zones while leaving cations unaffected, thereby achieving both high adsorption capacity and selectivity simultaneously
Solution Approach 2:
The patent uses composite materials by combining cationic layers with specific surfactants or metal oxides to create a multi-component adsorbent structure. This composite structure provides both the porous framework for high capacity and the charged layers for selective anion recognition, resolving the contradiction between quantity and selectivity
2Productivity
If electrolysis and precipitation are used to remove toxic substances from wastewater, then removal efficiency is improved, but device complexity increases due to complicated process requirements
Solution Approach 1:
The patent extracts the core function of toxic substance removal from complex electrochemical processes and simplifies it to a direct adsorption mechanism. By using adsorbent materials that directly bind toxic anions through electrostatic attraction, the invention eliminates the need for complicated electrochemical reactions, settlement aids, and absorption towers, thereby maintaining high removal efficiency while dramatically reducing device complexity
3Quantity of substance
If ion-exchange resin is used to remove toxic substances from wastewater, then adsorption capability is improved, but operational flexibility deteriorates due to limited pH range and temperature constraints
Solution Approach 1:
The patent applies parameter changes by using adsorbent materials with stable chemical properties that maintain their adsorption capability across a wide range of pH values and temperatures. The cationic layers are designed to remain stable and functional under varying operational conditions, allowing the system to adapt to different wastewater compositions and environmental conditions while maintaining high adsorption capability
4Quantity of substance
If conventional adsorbents are used for anion removal, then adsorption function is provided, but spatial constraints increase due to requirement of large-sized reactor and recovery apparatus
Solution Approach 1:
The patent uses porous materials with high surface area to volume ratio, which provide extensive adsorption sites within a compact structure. The porous framework allows toxic anions to be captured efficiently throughout the material volume, enabling high adsorption function to be achieved in a much smaller reactor volume compared to conventional dense adsorbents
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 enables the selective, irreversible adsorption of toxic anions with increased specific surface area, reducing environmental impact and spatial constraints, and improving adsorption efficiency in various wastewater types.
Implementation Method 1
a method for removing toxic anions from wastewater by adsorption using an anion adsorbent... comprising a plurality of spaced cationic layers, at least one anion that provides coupling between each adjacent two of the cationic layers
Data Source
AI summary
A method for preparing an anion adsorbent may be provided, which comprises the steps of: mixing at least two metal salts with each other, thereby forming a stack structure in which cationic compound layers and anionic compound layers containing anions and water of crystallization are alternately stacked on one another; performing a first heat treatment on the stack structure to expand between the cationic compound layers, thereby preparing a preliminary anion adsorbent; and performing a second heat treatment on the preliminary anion adsorbent to remove the anions and the water of crystallization from the anionic compound layers while allowing at least one of the anions to remain, thereby preparing the anion adsorbent.