Related Experiment Video
Updated: May 22, 2026
08:01
Removal of Arsenic Using a Cationic Polymer Gel Impregnated with Iron Hydroxide
Published on: June 28, 2019
Adsorption of anionic dyes from aqueous solutions using chemically modified straw.
Wenxuan Zhang1, Haijiang Li, Xiaowei Kan
1State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
Bioresource Technology
|May 22, 2012
Summary
Modified wheat straw effectively removes methyl orange and acid green 25 dyes. This eco-friendly adsorbent shows high capacity and can be reused for secondary dye adsorption, aiding resource utilization.
Area of Science:
- Environmental Chemistry
- Materials Science
- Adsorption Science
Background:
- Effective disposal of agricultural waste like straw is crucial for environmental protection and resource management.
- Developing novel adsorbents from renewable resources offers sustainable solutions for wastewater treatment.
- Dye contamination in water bodies poses significant environmental and health risks.
Purpose of the Study:
- To prepare quaternary ammonium straw adsorbents from wheat straw via etherification.
- To investigate the adsorption performance of modified straw for methyl orange (MO) and acid green 25 (AG25) dyes.
- To evaluate the potential for secondary adsorption using spent adsorbents.
Main Methods:
- Wheat straw modification through etherification to introduce quaternary ammonium groups.
- Batch and column adsorption experiments to determine dye uptake capacities and adsorption mechanisms.
- Characterization of adsorption equilibrium, kinetics, and regeneration potential.
Main Results:
- Modified straw exhibited significantly enhanced adsorption capacities for both MO and AG25.
- Maximum adsorption uptakes reached over 300 mg/g for MO and 950 mg/g for AG25.
- Adsorption followed monolayer chemical adsorption via an ion-exchange process.
- Spent adsorbents successfully adsorbed a cationic dye in a secondary adsorption step due to altered surface structures.
Conclusions:
- Etherification of wheat straw yields highly efficient adsorbents for anionic dyes.
- The modified straw demonstrates excellent adsorption capacity and potential for reuse, aligning with circular economy principles.
- This approach offers a sustainable and cost-effective method for dye removal from wastewater.
Related Concept Videos
01:17Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...
03:11Precipitation of Ions
Predicting Precipitation
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:
01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.