Ethylenediamine modified starch as biosorbent for acid dyes

Area of Science:

• Environmental Chemistry
• Materials Science
• Adsorption Science

Background:

• Acid dyes are common industrial pollutants in wastewater.
• Effective removal of acid dyes is crucial for environmental protection.
• Biosorbents offer a sustainable alternative for dye remediation.

Purpose of the Study:

• To investigate the sorption performance of ethylenediamine modified starch (CAS) for acid dye removal.
• To evaluate the influence of pH, kinetics, and equilibrium on dye adsorption.
• To understand the interaction mechanism and desorption behavior of dyes from CAS.

Main Methods:

• Sorption experiments were conducted using ethylenediamine modified starch (CAS) as a biosorbent.
• Adsorption of acid orange 10 (AO10), acid green 25 (AG25), and amido black 10B (AB10B) was studied under varying pH conditions.
• Sorption kinetics, equilibrium uptake, and desorption in sodium sulfate solutions were analyzed.

Main Results:

• Adsorption mechanisms involved electrostatic attraction and hydrogen bonding.
• Adsorption kinetics followed pseudo-second-order for AG25 and AB10B, and both pseudo-first-order and pseudo-second-order for AO10.
• Langmuir equation best described adsorption equilibrium, with capacities ordered as AB10B > AG25 > AO10, influenced by hydrophilic functional groups.

Conclusions:

• Ethylenediamine modified starch (CAS) demonstrates significant potential for acid dye removal from aqueous solutions.
• Dye adsorption is influenced by pH, dye structure (hydrophilic groups), and interaction mechanisms (electrostatic attraction, hydrogen bonding).
• Dye desorption is dependent on salt concentration and dye characteristics.