Acid Bleaching of Reclaimed Cellulose for Low-Clogging Regeneration
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Solution Overview
Problem
Existing methods for regenerating cellulose are inefficient and costly, with a high propensity for clogging due to metal content, requiring multiple stages and the use of complex agents like EDTA, which poses environmental concerns.
Innovation Solution
A one-stage process combining acid metal removal and acid oxidative bleaching to efficiently reduce metal content and clogging in reclaimed cellulose fibers, eliminating the need for additional bleaching and metal removal steps, using acids like hydrochloric, formic, or acetic acid, and oxidative agents like hydrogen peroxide or ozone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple stages are used for metal removal and bleaching, then metal content and clogging are reduced, but process complexity and cost increase
Solution Approach 1:
The patent combines acid metal removal and acid oxidative bleaching into a single integrated stage, where both functions are performed simultaneously using the same acidic environment and oxidative agents, eliminating the need for separate treatment stages while achieving both metal removal and bleaching objectives
Solution Approach 2:
The acidic oxidative treatment stage serves multiple functions simultaneously: it acts as both a metal removal agent through acid dissolution and a bleaching agent through oxidative reactions, making the process step multi-functional and reducing overall process complexity
2Object-affected harmful factors
If EDTA is used for metal removal, then metal content is reduced, but environmental harm increases
Solution Approach 1:
The patent replaces the environmentally harmful EDTA chelating agent with environmentally benign acidic oxidative agents that achieve metal removal through acid dissolution and oxidation mechanisms, converting the harmful chemical approach into a more sustainable process that eliminates persistent environmental contaminants
Solution Approach 2:
The patent uses readily available, inexpensive acidic agents (such as sulfuric acid, hydrochloric acid, or organic acids) and oxidative agents (such as hydrogen peroxide, sodium hypochlorite, or ozone) that can be easily degraded in the environment, replacing expensive and persistent EDTA with simpler, more environmentally friendly alternatives
3Object-affected harmful factors
If multiple treatment stages are used, then metal removal efficiency is improved, but processing time increases
Solution Approach 1:
The patent merges acid metal removal and acid oxidative bleaching into a single simultaneous treatment stage, where both metal dissolution and oxidative bleaching occur concurrently in the same reactor under the same conditions, thereby reducing total processing time while maintaining effective metal removal
Solution Approach 2:
The patent implements a continuous single-stage process where acid metal removal and oxidative bleaching proceed simultaneously without interruption or intermediate steps, maintaining continuous useful action throughout the treatment period and eliminating time losses associated with stage transitions
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 significantly reduces clogging and metal content in regenerated cellulose, making the process faster, more efficient, and cost-effective, while avoiding the environmental issues associated with EDTA, by oxidizing and removing metal ions in a single stage.
Implementation Method 1
acid metal removal
Implementation Method 2
treatment with a complexing agent
Implementation Method 3
acid oxidative bleaching
Implementation Method 4
oxidative bleaching stage can be treatment with peroxide, oxygen or ozone
Implementation Method 5
exposing the cellulose containing material to oxygen with an alkali aqueous solution
Implementation Method 6
swelling the cellulose
Implementation Method 7
bleached with ozone at acid conditions
Implementation Method 8
oxidative agents like hydrogen peroxide or ozone
Implementation Method 9
oxidizing and removing metal ions
Data Source
AI summary
There is provided a process for chemically pretreating reclaimed cellulose fibres to be used in the production of moulded bodies from regenerated cellulose, wherein the pretreatment includes one stage, in which stage acid metal removal and acid oxidative bleaching are carried out together. Advantages include that the propensity of the regenerated cellulose to clog when flowing in a tube and through a nozzle is reduced. This is believed to be an effect of an efficient metal removal. The need for additional bleaching steps and/or metal removing steps is reduced or even eliminated. A one-stage method is more efficient, faster and less costly compared to a multi-stage method according to the prior art. From an environmental perspective, acidic metal removal is preferred over removal by chelating agents such as EDTA.