Delaminated sodium titanate nanobelts in synergy with cationic polyacrylamide to induce flocculation on kaolin clay

Nanoparticle with higher aspect ratio and greater surface area renders higher micro-bridging ability in flocculating paper furnishes adsorbed with cationic polymers. Sodium titanate nanobelt is a typical one-dimensional nano-material with extremely high aspect ratios. In this paper, the nanobelt was synthesized hydrothermally and successfully peeled with tetramethylammonium hydroxide (TMAOH). The peeled nanobelt was characterized by XRD, TEM, BET surface area and surface charge measurement, and employed as a microparticle component partnered with cationic polyacrylamide (CPAM) to constitute a retention system. The flocculation behavior of kaolin clay by CPAM/nanobelt system was investigated using a photometric dispersion analyzer connected with a dynamic drainage jar. The morphology of flocculated kaolin was characterized by TEM and optical microscope. The results showed that the peeling treatment reduced both the length and the width of nanobelt, increased the charge density and sorption capacity to CPAM but did not significantly alter its structure and zeta potential in aqueous dispersion. The peeled nanobelts partnered with CPAM offered the biggest synergistic flocculating effect at a very low dosage, especially the ones that were peeled for 6–10 days. The kaolin flocs induced by CPAM/peeled nanobelt were larger and denser than those induced by CPAM alone, and become even denser but smaller with increased peeling time.