[Impact of SDBS/Na+ on red soil colloidal stability]

Area of Science:

• Soil Science
• Colloid Chemistry
• Environmental Chemistry

Background:

• Soil colloidal particles interact with contaminants and ions, influencing soil properties.
• Understanding these interactions is crucial for soil management and environmental remediation.

Purpose of the Study:

• To investigate the coupled effects of sodium dodecylbenzene sulfonate (SDBS) and sodium ions (Na+) on red soil colloid aggregation.
• To elucidate the interaction mechanisms between soil colloids and SDBS/Na+.

Main Methods:

• Dynamic light scattering was used to measure aggregate size and aggregation rates.
• pH and Zeta potential measurements were employed to analyze interaction mechanisms.

Main Results:

• Increasing SDBS concentration stabilized soil colloids, decreasing aggregate size and aggregation rates under constant Na+ levels.
• Increasing Na+ concentration enhanced aggregation, reducing Zeta potential while increasing aggregate size and aggregation rates under constant SDBS levels.
• SDBS adsorption onto soil colloids, driven by hydrophobic and electrostatic effects, increased surface charge and reduced effective Na+ concentration, leading to greater stability.

Conclusions:

• SDBS adsorption stabilizes red soil colloids by altering surface charge and reducing Na+ availability.
• The interplay between SDBS and Na+ concentrations dictates the aggregation behavior and stability of red soil colloids.