Modulation of the morphology, surface energy and wettability of malachite through a S,O,O-ligand surfactant: Mechanism and hydrophobization

Abstract

The modulation of solid surface properties via surfactants has a wide application in surface engineering. In this study, a novel S,O,O-ligand surfactant N-[(4-hydroxyamino)-4-butoxyl]-S-hexyl-dithiocarbamate (HABHTC) was first introduced to hydrophobize malachite surface. AFM morphology image clearly displayed that the dense HABHTC aggregates adsorbed on the whole surface of malachite, which increased its contact angle, decreased its surface energy, hydrophilicity index and interaction free energy with bubble. HABHTC exhibited stronger hydrophobization to malachite than calcite and quartz. FTIR and XPS recommended that HABHTC acted as a S,O,O-ligand to bond surface Cu atoms of malachite via building CuS and CuO bonds. The S,O,O-coordination enhanced the stability of Cu-HABHTC surface species on malachite and rendered HABHTC to possess better flotation specificity toward malachite versus calcite than octyl-hydroxamic acid (OHA). The C6H13SCNC3H6 configuration of HABHTC dramatically strengthened its hydrophobization toward malachite surface, resulted in a preferable hydrophobic flotation of malachite particles by using HABHTC as a collector.