| One-dimensional nanomaterials have been widely used because of their special geometry effects. In experiment, negatively charged sodium titanate nanobelt and nanotube were synthesized by a hydrothermal treatment of titanium dioxide in concentrated sodium hydroxide. The influence of temperature and time on the synthesis of the titanate nanomaterials was studied, and the products were characterized by TEM observation and zeta potentioal measurement. Then, the retention and flocculation effects of the sodium titante nanomaterials as a single coagulant and anionic microparticulate component with cationic polyacrylamide (CPAM) on fibers and fillers were investigated by means of dynamic drainage jar (DDJ) and photometric dispersion analyzer (PDA2000), respectively. The retention mechanisms and flocculation characters of the sodium titanate with CPAM were analyzed by transmission electron microscopy (TEM). Additionly, the flocculation effect of nanobelt was contrasted with that of titanium dioxide and magnesium hydroxide chloride hydrate nanowires either used alone or together with CPAM.Results indicate that the synthesized sodium titante one-dimensional nanomaterials are crystals and their morphology was inpacted greatly by temperaure. The product of lower temperature (150 oC) is nanotube with a typical length of 1.5~5.0μm and a diameter of 30 ~ 70 nm while the product of higher temperature (180 oC) is nanobelt, whose length and uniformity increased by postponding the reaction time. The length of most of the nanobelt is 7μm when time is as long as 72h. The width is 50~80 nm. In addition, it was found that the sodium titanate nanobelt and nanotube carried negative charges and their zeta potentials decreased as pH value increased from 4 to 6, but kept constant from pH 6 to pH 8.Both of sodium titante nanobelt and nanotube only cause a weak flocculation of kaolin clay. However, they show good synergistic effects with CPAM on filler flocculation at a very low dosage. Higher CPAM dosage give larger filler flocculation as the sodium titanate one-dimensional materials are employed as microparticle retention aids. In addition, they show higher flocculation effect with CPAM under neutral and weak alkaline conditions and induce filler flocculation with the character of bridging flocculation. The length of sodium titanate nanobelt has a great impact on flocculation. The flocculation of kaolin clay is inhanced as the length increased, but too long nanobelt is unfavorable to filler flocculation because of the aggregation of sodium titanate nanobelt. The titanate nanobelt with a reaction time of 24 h shows highest synergistic flocculation effect with CPAM on filler. Its length is 3μm. Furthermore, the filler flocculation induced by CPAM/titanate nanobelt or nanotube has a high shear resistance and the filler flocs are dense.Compared with spherical titanate dioxide, sodium titanate nanobelt and nanotube cause better clay flocculation at lower dosage as they used together with CPAM. However, nanobelt induces a weaker flocculation than titanate dioxide, while nanotube induces almost same flocculation with titanate dioxide at larger dosage. Comparing sodium titanant nanobelt with magnesium hydroxide chloride hydrate nanowires, it is found that the sodium titanate nanobelt induces a weaker flocculation of talc filler as used alone, but it induces a filler floculation nearly as strong as magnesium hydroxide chloride hydrate nanowires induces one as it used together with CPAM. Also, the sodium titanate nanobelt induces the maximum filler flocculation at a lower dosage and less CPAM addition level. Both magnesium hydroxide chloride hydrate nanowire and sodium titanate nanobelt and nanotube belong to micriparticle retention aid. Higher stirring speed after CPAM is immediately added, often results in higher final clay flocculation. However, the flocs induced by CPAM/magnesium hydroxide chloride hydrate nanowire have lower shear resistance.
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