Adsorption mechanism of collector a-Bromolauric acid (CH3(CH2)(9)CHBrCOOH, alpha-BLA) on alpha-quartz (101) surface has been investigated by first-principles calculations based on density functional theory (DFT). The interaction energies of H2O molecule, calcium ions (Ca2+), hydroxyl ions (OH-), calcium hydroxyl ions (Ca(OH)(+)), and alpha-BLA(-) ions with alpha-quartz (101) surface were in the order of Ca (OH)(+) < Ca2+ < OH- < H2O < alpha-BLA(-). The results revealed that the collector alpha-BLA cannot adsorb on alpha-quartz (101) surface due to the hindrance of hydration shell of quartz surface, while Ca(OH)+ could repulse the hydration shell and consequently adsorb on quartz surface, which further leads to the adsorption of the collector alpha-BLA(-) anions on Ca(OH)(+)-activated quartz surface. Mulliken populations analysis of the external oxygen atom (02) of quartz surface, calcium atom (Ca) of Ca(OH)(+), and oxygen atom (01) of collector alpha-BLA(-) (-OH group) shows that the electron transfer between the Ca-O1 and. Ca-O2 atoms. The overlap area of electron density between Ca-O1 and Ca-O2 atoms indicates strong interactions among the three atoms of Ca, 01, and 02, suggesting that Ca(OH)(+) ions act as a bridge between the alpha-quartz (101) surface and the alpha-BLA collector. (C) 2016 Elsevier Ltd. All rights reserved.