Dye adsorption by prehydrolysed beech sawdust in batch and fixed-bed systems

Area of Science:

• Environmental Chemistry
• Materials Science
• Adsorption Science

Background:

• Wastewater contamination by synthetic dyes poses environmental challenges.
• Developing cost-effective adsorbents for dye removal is crucial.
• Beech sawdust is an abundant lignocellulosic material with potential adsorbent properties.

Purpose of the Study:

• To investigate the adsorption kinetics of methylene blue and red basic 22 on mild acid-hydrolysed beech sawdust.
• To evaluate the effectiveness of prehydrolysis in enhancing the adsorbent material's properties.
• To explore the potential of modified beech sawdust as a low-cost adsorbent for industrial wastewater treatment.

Main Methods:

• Batch and column adsorption experiments were conducted.
• Mild acid hydrolysis using sulfuric acid was employed for material modification.
• Adsorption data were analyzed using Freundlich's model and the Bohart and Adams' bed depth service model.
• Untreated beech sawdust served as a control.

Main Results:

• Mild acid hydrolysis significantly enhanced the adsorption capacities for both methylene blue and red basic 22.
• Freundlich's model indicated higher adsorption capacities for the treated sawdust.
• The Bohart and Adams' bed depth service model showed improved adsorption coefficient values.
• BET surface area analysis indicated an increase in surface area after hydrolysis.

Conclusions:

• Mild acid hydrolysis effectively improves the dye adsorption performance of beech sawdust.
• The enhanced adsorption is attributed to the removal of hemicelluloses, increased surface area, and more dye binding sites.
• Modified beech sawdust presents a promising, low-cost solution for removing dyes from wastewater.