SN@silicate: an anionic dye sorbent and its reuse

Abstract

It is difficult for dye-synthesizing wastewater to be treated efficiently together with eco-friendly disposal of dye sludge. Octadecyl dimethyl hydroxyethyl quaternary ammonium (SN) was hybridized with magnesium silicate, and then characterized by various techniques. The SN bilayer stacking via hydrophobic interactions intercalated into the magnesium silicate sheets and caused an interlayer increase to 4.9 nm. More than 40% SN was embedded so that the hybrid contained a large number of positive charges and hydrophobic areas. It exhibited a faster adsorption to anionic dyes with higher capacities from 108 to 553 mg g⁻¹ than for conventional sorbents. In addition, it captured microcystin-LR from water according to the lipid-water partition model. The resultant dye sludge was added into epoxy top coating and paint to fabricate colored films with an electric resistance decrease to 0.75 × 10⁷ Ω. The facile preparation of such a functional material provided a “killing two birds with one stone” approach, from treatment of dye wastewater to disposal of the dye sludge, turning it to an antistatic colorant.