Applied Surface Science, Vol.476, 460-467, 2019
Synthesis of 2-hydroxyethyl dibutyldithiocarbamate and its adsorption mechanism on chalcopyrite
In this paper, 2-hydroxyethyl dibutyldithiocarbamate (HEBTC) containing thione and hydroxy groups was synthesized and introduced as a new flotation surfactant for recovering chalcopyrite. HEBTC's chemical reactivity and dispersion performances were studied via DFT calculations and surface tension measurements. Its adsorption properties on chalcopyrite were systematically investigated by micro-flotation, adsorption tests, FT-IR and XPS analysis. DFT calculation results showed that the active sites of HEBTC located at C=S and -OH groups and HEBTC owned higher chemical reactivity than 2-ethyl dibutyldithiocarbamate (EBTC). Moreover, HEBTC displayed better dispersibility and hydrophilicity than EBTC in water. The micro-flotation tests demonstrated that HEBTC exhibited superior collecting ability than EBTC. Kinetic and isotherm data of the adsorption experiments could be well elucidated with the Pseudo-second-order model and Langmuir isotherm, indicating the adsorption of HEBTC on chalcopyrite was monolayer chemisorption. Thermodynamic studies showed that the adsorption of HEBTC on chalcopyrite was a spontaneous endothermic process. FT-IR and XPS analysis further proved that HEBTC were chemisorbed on the surface of chalcopyrite by formation of Cu-O and Cu-S bonds.