Interaction of titanium dioxide nanoparticles with kaolinite clay particles in the presence of quartz sand

Titanium dioxide (TiO₂) is one of the most frequently employed nanoparticles (NPs) in consumer products. The rapid development of nanotechnology has led to the inevitable introduction of NPs in the natural environment, which subsequently may reach underground formations. Also, kaolinite is one of the most common minerals, which can be found in the subsurface. Numerous experimental and theoretical studies have shown that kaolinite clay particles can impact on the transport behavior of colloids, biocolloids (bacteria, viruses) and engineered nanoparticles. Therefore, the aim of this study is to examine the interaction of kaolinite (KGa-1b) particles with suspended TiO₂ NPs in the presence of quartz sand.Static and dynamic batch experiments were performed with three different TiO₂ concentrations (50, 100, 200 mg/L) and four different ionic strength values ​​(1, 25, 50, 100 mM). All of the experiments were conducted at room temperature (22 °C) and pH=7.The experimental results clearly suggested that TiO₂ attachment onto KGa-1b particles was slightly enhanced with increasing TiO₂ concentrations,but significantly increased with increasing ionic strength. Consequently, the presence of suspended KGa-1b particles can retard the TiO₂ transport in water saturated porous media.