Solid Polymer Electrolyte Cell for Wastewater Treatment
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Solution Overview
Problem
Current wastewater treatment methods using electrochemical cells are inefficient due to high energy consumption, requirement of supporting electrolytes, and production of secondary pollution, especially in treating recalcitrant organic pollutants and inorganic compounds.
Innovation Solution
A solid polymer membrane electrolyte electrochemical cell design that operates without a liquid catholyte, using a voltage less than 3 volts and current density below 20 mA/cm², with specific catalysts and cell configurations to minimize side reactions and energy consumption, allowing for efficient pollutant degradation and hydrogen generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If supporting electrolyte is added to improve ionic conductivity, then cell efficiency is improved, but salt/base/acid concentrations exceed discharge limits requiring additional disposal costs
Solution Approach 1:
The invention extracts and removes the supporting electrolyte from the system by using a divided cell configuration where the catholyte is completely replaced by a solid polymer electrolyte membrane. This eliminates the need for liquid supporting electrolyte while maintaining ionic conductivity through the membrane, thereby preventing secondary pollution from salt/base/acid discharge.
Solution Approach 2:
The solid polymer electrolyte membrane acts as an intermediary between the anode and cathode, providing ionic conductivity while physically separating the compartments. This mediator enables ion transport necessary for cell efficiency without requiring liquid supporting electrolyte that would create harmful discharge concentrations.
2Device complexity
If large electrode gaps are used to accommodate cell design, then device complexity is reduced, but mass transport losses increase leading to higher energy consumption
Solution Approach 1:
The invention uses a thin solid polymer electrolyte membrane to create a compact cell structure with minimal electrode spacing. This thin film approach reduces the gap between electrodes to the minimum necessary distance, optimizing mass transport and reducing voltage requirements while maintaining structural integrity and simplicity.
3Productivity
If high current density is applied to increase treatment productivity, then pollutant removal rate is improved, but voltage must be increased leading to incomplete destruction and organic film blocking
Solution Approach 1:
The invention employs periodic cell reversal to clean the electrode surfaces by alternately making each electrode the cathode and anode. This periodic action prevents organic film accumulation by periodically stripping deposits, maintaining catalyst activity and treatment efficacy without requiring continuously high current densities that would cause incomplete destruction.
4Object-generated harmful factors
If divided cell configuration is used to eliminate supporting electrolyte, then secondary pollution is reduced, but hydrogen crossover to anode occurs reducing efficiency
Solution Approach 1:
The invention changes the physical and chemical parameters of the electrolyte from liquid to solid polymer membrane form. This parameter change fundamentally alters the transport properties, preventing hydrogen crossover while maintaining ionic conductivity. The solid membrane's selective ion transport properties eliminate the energy loss from hydrogen crossover that occurs in liquid electrolyte systems.
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 approach achieves high energy efficiency in wastewater treatment, eliminating pollutants and generating recoverable hydrogen, while reducing operational costs and environmental impact by eliminating the need for supporting electrolytes and minimizing secondary pollution.
Implementation Method 1
a solid polymer membrane electrolyte separating the anode and the cathode
Implementation Method 2
The anode comprises an anode catalyst layer, and the anode catalyst layer comprises an anode catalyst
Implementation Method 3
direct electrochemical oxidation, where the organic pollutants are oxidized on the anode surface
Implementation Method 4
The cathode in the electrolytic cell is liquid-electrolyte free
Data Source
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AI summary
An efficient method and system for the electrochemical treatment of waste water comprising organic and/or inorganic pollutants is disclosed. The system comprises an electrolytic cell comprising a solid polymer, proton exchange membrane electrolyte operating without catholyte or other supporting electrolyte. The cell design and operating conditions chosen provide for significantly greater operating efficiency.