Adsorption of basic fuchsin using soybean straw hydrolyzed by subcritical water

Area of Science:

• Environmental Chemistry
• Materials Science
• Biotechnology

Background:

• Agro-industrial residues present disposal challenges.
• Valorization of these residues is key for sustainable processes, including second-generation ethanol production.
• Developing efficient adsorbents from waste materials is crucial for environmental remediation.

Purpose of the Study:

• To investigate the potential of hydrolyzed soybean straw as an adsorbent for basic fuchsin.
• To optimize adsorption conditions and evaluate the performance of the adsorbent.
• To understand the adsorption mechanism and thermodynamic feasibility.

Main Methods:

• Subcritical water process to hydrolyze soybean straw.
• Batch adsorption experiments to test basic fuchsin removal.
• Kinetic and isotherm modeling (Linear Driving Force, Langmuir models).
• Thermodynamic analysis at various temperatures.

Main Results:

• Hydrolyzed soybean straw demonstrated high basic fuchsin adsorption capacity.
• Optimal conditions included pH 8 and an adsorbent dosage of 0.9 g L^-1.
• Adsorption equilibrium was reached within 30 minutes, best described by the Linear Driving Force model.
• The Langmuir model accurately predicted adsorption isotherms, with a maximum capacity of 72.9 mg g^-1 at 328 K.
• The process was spontaneous and endothermic.

Conclusions:

• Hydrolyzed soybean straw is a promising, cost-effective adsorbent for basic fuchsin removal.
• This application contributes to the full utilization of agro-industrial waste.
• The findings support the economic viability of second-generation ethanol production through waste valorization.