An impedance response model for inhibitory effect of antibiotics on bacterial growth in biometallurgy

An impedance response model reflecting the inhibitory effect of antibiotics on bacterial growth in biomet-allurgy was established. Three inhibition parameters, i.e. the maximum amount inhibitory constant of the bacterial growth(K1), the maximum specific growth inhibitory constant(K2) and the lag time inhibitory constant(K3), were included in the model. The influence of these parameters on the response curve was discussed in detail. By fitting experimental data towards the proposed model, three growth parameters (A,μm and λ) in the presence of antibiotics were gained and compared. The results show that the growth ability of bacteria is decreased due to the influence of antibiotics. The experimental and fitted curves have goodness-of-fit in the range of 0. 987-1. 008. Moreover, the kinetic growth parameters obtained from this model are closed to those from the Logistics popular growth model.These results show that the proposed model is validity to reflect the inhibitory effect of antibiotics on bacteria.

Mechanisms of flotation separation of diaspore and kaolinite by quaternary ammonium salt DTAL

The FTIR spectroscopy indicates that the adsorption of quaternary ammonium salt DTAL on the diaspore and kaolinite is physical adsorption. The adsorption of cationic surfactants measured by two-phase titration shows that the adsorption on the kaolinite is notably more than that on diaspore. The adsorption isotherm on kaolinte is linear while that of DTAL on diaspore is two-step flat form. The analysis on the cationic ions of kaolinite supernatants shows that kaolinite releases plenty of crystalloid structure ions which countervail the crystalloid charge because of the adsorption of the cationic surfactant. The mechanisms of the quaternary ammonium salt DTAL on flotation separation of diaspore and kaolinite include ion exchange interaction as well as electrostatic force.