Time-gradient nitric acid modification of cf biofilm-carrier and surface nature effects on microorganism immobilization behavior in wastewater

Abstract

PAN-based carbon fiber (CF) biofilm-carrier was modified by nitric acid for a different oxidation time. The CF surface morphology and nature were characterized by laser confocal microscopy (LCM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and degree of moisture (DM). In addition, the biocompatibility of CF was discussed based on the immobilization behavior of microorganisms. The results indicated that the HNO3 oxidation treatment could be regarded as a favorable surface treatment for the CF carrier. The surface oxygen content and hydrophilicity were shown to affect the immobilization ability of microorganisms and influence biofilm formation on the CF surface. Among these, the carboxyl content on the CF surface contributed greatly to microorganism immobilization. The configurations and adhesion forms of cells were considerably affected by the properties of the CF surface. The results from this study could be helpful in the study of microorganism adhesion mechanisms and could be regarded as promising in view of preparation of high biocompatibility biocarriers in the field of water treatment.