Graphene Oxide Production With Low-Impurity Scalable Oxidation
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Solution Overview
Problem
Existing methods for producing graphene oxide, such as the Hummers' method, suffer from drawbacks like the release of toxic gases, high costs, and poor scalability, making it difficult to meet the growing demand for a cost-effective and scalable manufacturing process.
Innovation Solution
A process involving the treatment of graphite with sulphuric acid at low temperatures, followed by the addition of potassium permanganate and mechanical agitation, then using hydrogen peroxide to form a suspension, which is washed with water and dilute hydrochloric acid, and finally freeze-dried to produce graphene oxide with minimal impurities and high carbon-to-oxygen ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If Hummers' method is used to synthesize graphene oxide, then the reaction time is shortened and ease of reaction is improved, but toxic gases are liberated and residual nitrates remain in the product
Solution Approach 1:
The patent extracts and removes the harmful nitrate component from the oxidation system by replacing potassium nitrate with potassium persulfate as the oxidizing agent. This eliminates the generation of toxic nitrogen dioxide and dinitrogen tetroxide gases while avoiding residual nitrates in the final graphene oxide product, thereby resolving the contradiction between ease of reaction and harmful factor generation.
Solution Approach 2:
The patent employs potassium persulfate as a disposable oxidizing agent that decomposes completely during the reaction to form harmless byproducts (potassium sulfate and oxygen). This reagent is consumed in the reaction without leaving persistent harmful residues, allowing the process to maintain ease of operation while eliminating toxic gas evolution and nitrate contamination.
2Object-generated harmful factors
If modified Hummers' methods are proposed to address drawbacks, then some drawbacks are addressed, but the reaction proceeds for longer time resulting in higher costs and poor scalability
Solution Approach 1:
The patent changes the key chemical parameters of the oxidation system by substituting the oxidizing agents (from nitrate-based to persulfate-based) and adjusting the acid composition (using sulfuric acid and phosphoric acid in specific ratios). These parameter changes enable the reaction to proceed efficiently with reduced reaction time (2-4 hours) while eliminating toxic gas evolution and nitrate residues, thereby achieving both safety improvements and maintained productivity.
3Productivity
If a scalable manufacturing process is required to meet growing demand, then productivity must be improved, but existing methods have poor scalability due to toxic gas liberation and high costs
Solution Approach 1:
The patent converts the potentially harmful strong oxidizing action into a beneficial process by using potassium persulfate, which generates oxygen during decomposition rather than toxic nitrogen oxides. This oxygen evolution can be safely managed and the byproduct potassium sulfate is environmentally benign, enabling scalable production without the constraints of toxic gas handling and costly waste treatment required by traditional methods.
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 process achieves a graphene oxide product with low impurity content, high yield, and efficient energy use, while avoiding toxic by-products and maintaining the layered structure, suitable for various applications.
Implementation Method 1
treating the graphite source with sulphuric acid at a temperature in a range of −10° C. to 10° C. to obtain a graphite oxide
Implementation Method 2
converting the graphite oxide of the first reaction mixture to an initial graphene oxide in a second reaction mixture by adding potassium permanganate
Implementation Method 3
providing an oxidising mixture to the second reaction mixture to form a suspension, wherein the oxidising mixture comprises hydrogen peroxide
Implementation Method 4
freeze drying the dispersion under vacuum to obtain the graphene oxide product
Data Source
AI summary
The present disclosure provides a process for producing a graphene oxide product from a graphite source. The process comprises steps of treating the graphite source with sulphuric acid to obtain a graphite oxide in a first reaction mixture. The graphite oxide is converted to an initial graphene oxide in a second reaction mixture by adding potassium permanganate at room temperature. An oxidising mixture is added to the second reaction mixture to form a suspension. The process further comprises washing the suspension with water and dilute hydrochloric acid to obtain a wash liquor and a dispersion. The dispersion is freeze dried under vacuum to obtain the graphene oxide product. A graphene oxide product produced using the above process is also provided such that the graphene oxide product has an impurity content of less than 0.1%.