Sorption of Sr in granite under typical colloidal action

Area of Science:

• Geochemistry
• Environmental Science
• Materials Science

Background:

• Strontium (Sr) sorption onto geological materials is crucial for radioactive waste disposal safety.
• Understanding colloid influence on Sr sorption in granite is vital for predicting contaminant transport.

Purpose of the Study:

• To investigate the effect of common colloids (goethite, bentonite, humic acid) on strontium sorption by granite.
• To determine the influence of initial Sr concentration and pH on sorption behavior.

Main Methods:

• Batch sorption experiments were conducted using granite with and without colloids.
• Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) characterized granite surfaces.
• Sorption was analyzed under varying Sr concentrations and pH levels.

Main Results:

• Colloids significantly increased Sr sorption capacity in granite by 1.8 to 2.13 times.
• Sorption increased with initial Sr concentration, but sorption percentage decreased.
• Maximum Sr sorption occurred at pH 7, decreasing with increasing acidity or alkalinity.
• Granite surface analysis revealed increased roughness post-sorption.

Conclusions:

• Colloids play a critical role in enhancing strontium sorption in fractured granite systems.
• Sorption mechanisms likely involve interactions with granite's mineral components and attached water molecules.
• pH is a key factor controlling strontium sorption onto granite, with optimal performance near neutral conditions.