Transport behaviors of graphene oxide nanoparticles（GONPs） in saturated porous media were examined as a function of the presence and concentration of anionic surfactant（SDBS）and non-ionic surfactant（Triton X-100） under different ionic strength（IS）. The results showed that the GONPs were retained obviously in the sand columns at both IS of 50 and200 mmol/L, and they were more mobile at lower IS. The presence and concentration of surfactants could enhance the GONP transport, particularly as observed at higher IS. It was interesting to see that the GONP transport was surfactant type dependent, and SDBS was more effective to facilitate GONP transport than Triton X-100 in our experimental conditions. The advection–dispersion–retention numerical modeling followed this trend and depicted the difference quantitatively. Derjaguin–Landau–Verwey–Overbeek（DLVO）interaction calculations also were performed to interpret these effects, indicating that secondary minimum deposition was critical in this study.
Novel matrix beads for the immobilization of strain Comamonas testosteroni sp. bdq06 to degrade quino- line were fabricated from polyethersulfone（PES）. The beads have an average size of 3 mm and a surface dense layer of 20 microns. To help adhesion and proliferation of bacterial cells, the surfaces of the PES beads were etched, and numerous holes about 1.5 micrometers in diameter were generated as tunnels for cell colonizing in the larger internal cavities of about 5 micrometers in diameter. The quinoline degradation was remarkably enhanced by the cells immo- bilized in PES beads compared with that by the free cells at pH 5.0 or 10.0 and a temperature of 40 ℃. The enhanced degradation of quinoline was contributed to the biofilm on the surface of PES beads, resulting in the significant re- duction of retention time from 9 h to 2 h. Furthermore, the beads remain intact after the ultrasonic treatment of them for 30 rain or recycling 50 times, indicating that they have excellent mechanical strength, flexibility and swelling ca- pacity. Thus, PES beads have great potential to be matrix for the cell immobilization in bioaugmentation.
