The surface behavior of Rhodococcus opacus on calcite, serpentine and dolomite

摘要

The surface property of minerals can be influenced and changed by microbial special nature when microorganism is adhered to the mineral surface, which contributes to change mineral floatability to separate gangues. This paper focused on the Rhodococcus opacus (R. opacus) adsorption behavior on surface of calcite, serpentine and dolomite by bio adhesive test, contact angle measurements, zeta potential, FTIR spectra and TEM images. The results showed that Rhodococcus opacus could be absorbed onto the surface of calcite, serpentine and dolomite in a few minutes, and the adsorption rate is very high as 96%. The cell adsorption was dependent on the pH value and the most suitable pH is 1.2, while there is no significant influence of temperature on bacterial adsorption. Increasing pulp density could provide enough adsorption sites to Rhodococcus opacus, and the adsorption rate could be raised consequently. The minerals contact angle decreased after Rhodococcus opacus attached on the surface, indicating that their dispersibility was improved in favour of separation. Zeta potential measurements showed that the cell with charge was opposite to the minerals on the broad pH value scope. The TEM images showed that R. opacus combined tightly with mineral, and a large number of small mineral particles gathered around the cell and FTIR spectra showed the presence of some groups on the cell wall gave a net charge on the surface.