Graphene Oxide Manufacture from Kish Graphite
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Solution Overview
Problem
Conventional methods for manufacturing graphene oxide from Kish graphite are environmentally unfriendly due to the production of toxic gases and require lengthy chemical treatments, leading to reduced productivity and lower quality graphene oxide with poor properties.
Innovation Solution
A method involving a pre-treatment step that includes sieving, flotation, and acid leaching of Kish graphite, followed by an oxidation step using ammonium nitrate and potassium permanganate, with controlled temperature and addition of a chemical element to stop the oxidation reaction, resulting in high-purity graphene oxide with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional Hummer method is used with sodium nitrate and sulfuric acid, then graphene oxide can be synthesized, but toxic gases (NO2, N2O4, NH3) are produced which are harmful to the environment
Solution Approach 1:
The patent changes the chemical parameters of the oxidation system by replacing sodium nitrate with ammonium nitrate and adjusting the oxidizing agent concentration ratios. This substitution fundamentally alters the reaction pathway to eliminate toxic nitrogen oxide gases while maintaining effective oxidation of graphite to graphene oxide, thus resolving the contradiction between production quantity and harmful emissions
Solution Approach 2:
The patent converts the potentially harmful oxidation process into a beneficial one by selecting oxidizing agents and conditions that produce non-toxic byproducts. The oxidation reaction still achieves the desired conversion of graphite to graphene oxide, but the harmful toxic gases are replaced with harmless products, turning a harmful process into a beneficial one
2Manufacturing precision
If two-step chemical pretreatment (flushing and purification) is applied to Kish graphite, then purification is improved, but chemical waste increases and process complexity increases
Solution Approach 1:
The patent merges the flushing and purification steps into a single integrated acid leaching process using nitric acid. This combined approach achieves both removal of surface contaminants and purification of the graphite structure in one operation, reducing process complexity and chemical waste while maintaining high purification quality
Solution Approach 2:
The acid leaching step serves multiple functions simultaneously: it acts as both a flushing agent to remove surface impurities and a purification medium to clean the graphite structure. This multi-functional approach eliminates the need for separate treatment steps, reducing overall process complexity
3Quantity of substance
If conventional oxidation with sodium nitrate is used, then oxidation reaction proceeds, but oxidation time is prolonged reducing productivity
Solution Approach 1:
The patent changes the chemical parameters by using ammonium nitrate instead of sodium nitrate and optimizing the oxidizing agent concentration and temperature conditions. These parameter changes accelerate the oxidation reaction kinetics, significantly reducing oxidation time while maintaining high graphene oxide yield, thus resolving the contradiction between quantity and productivity
4Quantity of substance
If modified Hummer method is used to obtain graphene oxide, then production is achieved, but lateral size is reduced to about 3 μm leading to poor properties
Solution Approach 1:
The patent applies preliminary acid leaching treatment to Kish graphite before oxidation to remove impurities and prepare the graphite structure. This preliminary action prevents unwanted side reactions during oxidation and helps maintain larger lateral sizes in the final graphene oxide product, avoiding the size reduction problem of conventional 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 method produces high-quality graphene oxide with increased oxygen functional groups, reduced environmental impact, and shorter oxidation times, making it suitable for industrial-scale production with improved thermal and electrical conductivities.
Implementation Method 1
an oxidation step of the pre-treated kish-graphite obtained after step B) in order to obtain graphene oxide comprising the following successive sub-steps: i. the preparation of a mixture comprising the pre-treated kish-graphite, an acid and ammonium nitrate (NH4NO3), the mixture being kept at a temperature below 5° C., ii. the addition of an oxidizing agent into the mixture obtained in step C.i)
Data Source
AI summary
A method for the manufacture of graphene oxide from Kish graphite including the pretreatment of kish graphite and the oxidation of pre-treated kish graphite into graphene oxide, the graphene oxide obtained with at least 45% by weight of oxygen functional groups and the use of the graphene oxide.