Deashed Wheat-Straw Biochar as a Potential Superabsorbent for Pesticides

Area of Science:

• Environmental Chemistry
• Materials Science

Background:

• Biochar activation enhances sorptive properties for pollutant removal.
• Chemically modified biochars show potential for soil and water purification from xenobiotics.

Purpose of the Study:

• To investigate the physicochemical property changes of wheat-straw biochar (BC) after deashing (BCd).
• To evaluate the pesticide retention capacity of pristine and deashed biochar.

Main Methods:

• High-temperature wheat-straw biochar (BC) was deashed to produce BCd.
• Adsorption of five endocrine-disrupting pesticides (carbaryl, carbofuran, 2,4-D, MCPA, metolachlor) was studied on both BC and BCd.

Main Results:

• Deashing increased biochar aromaticity, surface hydroxyl groups, and surface area (nearly tripled).
• Hydrophobic pesticides showed high adsorption (88-98%) on both BC and BCd.
• Hydrophilic pesticides were weakly adsorbed on BC but nearly totally removed by BCd due to enhanced surface area and hydroxyl group interactions.

Conclusions:

• Deashing significantly improves biochar's physicochemical properties for pollutant sorption.
• Modified biochar (BCd) acts as a superabsorbent for immobilizing diverse organic pollutants from aqueous and soil solutions.