Related Experiment Video
Updated: Jun 12, 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 solution on fly ash
Deshuai Sun1, Xiaodong Zhang, Yude Wu
1College of Chemistry & Chemical Engineering, Qingdao University, Qingdao, China. luckysds@163.com
Journal of Hazardous Materials
|June 24, 2010
Summary
Fly ash effectively removes reactive and acid dyes from wastewater. This study optimized adsorption conditions like pH and contact time, finding the process to be pH-dependent and endothermic.
Area of Science:
- Environmental Chemistry
- Materials Science
- Water Treatment
Background:
- Textile dyes, including reactive and acid dyes, are significant water pollutants.
- Fly ash, a waste material from coal combustion, presents a potential low-cost adsorbent for wastewater treatment.
Purpose of the Study:
- To investigate the adsorption capabilities of fly ash for removing reactive dyes (Reactive Red 23, Reactive Blue 171) and acid dyes (Acid Black 1, Acid Blue193) from aqueous solutions.
- To determine the optimal conditions for dye adsorption onto fly ash.
Main Methods:
- Batch adsorption experiments were conducted.
- Adsorption was studied as a function of solution pH, contact time, initial dye concentration, and temperature.
- Adsorption equilibrium and kinetic data were analyzed using isotherm (Langmuir, Freundlich) and kinetic (pseudo-second-order) models.
- Thermodynamic parameters were evaluated.
Main Results:
- Fly ash demonstrated significant adsorption capacity for all four dyes.
- Optimal adsorption pH was 7.5-8.5 for reactive dyes and 5-6 for acid dyes.
- Adsorption equilibrium was reached within 60 minutes at 293 K.
- Adsorption capacity increased with initial dye concentration, but removal efficiency did not.
- Pseudo-second-order kinetics and a combination of Langmuir and Freundlich isotherms best described the adsorption behavior.
- The adsorption process was found to be spontaneous and endothermic.
Conclusions:
- Fly ash is a viable and cost-effective adsorbent for removing reactive and acid dyes from textile wastewater.
- Dye removal by fly ash is highly dependent on solution pH.
- The adsorption mechanism follows pseudo-second-order kinetics and can be described by Langmuir and Freundlich models, indicating a complex interaction between dyes and fly ash.
More Related Videos
09:34Synthesis and Characterization of Fe-doped Aluminosilicate Nanotubes with Enhanced Electron Conductive Properties
Published on: November 15, 2016
10:44Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for Cu(II) Through Microwave Pre-Pyrolysis
Published on: February 12, 2019
Related Concept Videos
04:01Factors Affecting Solubility
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
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:
01:08Sample Preparation for Analysis: Advanced Techniques
Accurate analysis of complex samples often requires advanced preparation techniques to achieve reliable and reproducible results. Samples containing inorganic or organic materials can be challenging to dissolve or decompose effectively. Standard sample preparation methods include acid digestion, fusion, dry ashing, and wet digestion.
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
00:52Washing, Drying, and Ignition of Precipitates
After filtration, the precipitate is washed to remove coprecipitated impurities and any remaining mother liquor. Colloidal precipitates, such as silver chloride, are washed with an electrolyte (such as dilute nitric acid) to prevent the peptization of the precipitate. In the case of slightly soluble precipitates, the wash solution contains a common ion to reduce solubility. Lead sulfate, which is slightly soluble in water, is washed with dilute sulfuric acid. Similarly, wash solutions may be...
01:09Colloidal precipitates
The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
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.