The interaction between diesel and surfactant Triton X-100 and their adsorption on coal surfaces with different degrees of oxidation

u Poor flotation of oxidised coals is a major challenge confronting coal preparation plants worldwide. Despite a number of studies to improve the flotation of oxidised coals using surfactants to adsorb on oxidised coal surfaces, the industry continues to use diesel as the dominant collector to float oxidised coals with a low efficiency. Following the previous study employing a composite collector consisting of diesel and surfactant Triton X-100 to improve the surface hydrophobicity of oxidised coals with diesel targeting un-oxidised surface areas while Triton X-100 targeting oxidised surface areas (Chang et al., 2017 [1]), the current study investigated the synergistic interaction between Triton X-100 and diesel and their adsorption on coal surfaces with different degrees of oxidation in flotation. It was found that the superior performance of the composite collector in the flotation of oxidised coals was attributed to the emulsification of diesel by Triton X-100 and the adsorption of Triton X-100 on oxidised surface areas. Triton X-100 molecules which adsorbed at the oil/water interfaces emulsified the diesel, significantly decreasing the size of diesel droplets and facilitating the adsorption of diesel on un-oxidised surface areas. On oxidised surface areas, Triton X-100 adsorbed through a "head-on" adsorption, rendering the hydrophilic surface hydrophobic. (C) 2018 Elsevier B.V. All rights reserved.