Understanding the hydrophobic mechanism of 3-hexyl-4-amino-1, 2,4-triazole-5-thione to malachite by ToF-SIMS, XPS, FTIR, contact angle, zeta potential and micro-flotation

The hydrophobic mechanism of 3-hexyl-4-amino-1, 2, 4-triazole- 5-thione (HATT) to malachite (Cu2CO3(OH)(2)) was investigated by contact angle, micro-flotation, zeta potential, Fourier transform infrared (FTIR) spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectra (XPS). After HATT modification, the wettability of malachite surfaces was changed from hydrophilicity to hydrophobicity, and its zeta potential moved to more negative values, demonstrating that HATT might adsorb on the positively charged copper species via its anionic amino-triazole-thione group with leaving its hexyl group against malachite surfaces. The hydrophobized malachite particles attached selectively to air bubbles and subsequently moved to the pulp surface with the bubbles. FTIR and ToF-SIMS indicated that HATT might chemisorb on malachite surfaces by formation of Cu-S and Cu-N bonds with the breakage of S-H bond in HATT thiol tautomer. XPS further elucidated that a five membered-ring HATT-Cu(I) surface complex was formed by bonding the exocyclic S and N atoms of HATT with the copper atom on malachite surfaces. (C) 2016 Elsevier B.V. All rights reserved.