Microbial Attachment Behavior and Pollutant Removal Performance of Modified Quartz Sand
Biological sand filter (BSF) is used to cultivate the biofilm on the surface of the filter material on the ordinary sand filter, and increase the removal capacity of the pollutants by the quartz sand filter material, and the transformation of the ordinary sand filter can be realized without the need to increase the large structure. Quartz sand filter is the core of biological sand filter. Its surface characteristics directly affect the formation of biofilm and determine the ability to remove pollutants. However, the surface of ordinary quartz sand filter is smooth and the specific surface area is small. Based on the above defects of common quartz sand, the ordinary quartz sand filter material is modified to improve the microbial affinity of quartz sand filter material, and then the modified biofilter (MBSF) is an effective means to improve the removal efficiency of the biofilter. In this study, BOE corrosion solution was used to treat ordinary quartz sand by chemical etching to obtain surface restructured sand to improve the surface roughness and specific surface area of ordinary quartz sand. Then, the surface reformed sand was modified by hydrophilic and hydrophobic, cation and amino compound modification, and the modified quartz sand with different chemical properties was obtained, and some modification conditions were optimized. The results show that different modification methods have a significant effect on the surface properties of quartz sand: The surface of the surface reconstructed sand showed a groove shape, and the specific surface area increased from 1.033m2/g of ordinary quartz sand to 4.857m2/g; The surface contact angle of hydrophilic modified sand decreased to 43 degrees; the surface contact angle of hydrophobic modified sand increased to 91 degrees; the Zeta potential of cationic modified surface increased to +3.7. The adsorption performance of quartz sand shows that the adsorption ability of cationic modified sand to iodine, methylene blue and tannic acid is the strongest, but the adsorption ability of ordinary quartz sand to three representative substances is weakest because of small specific surface area and weak adsorption capacity.