Abstract:

Ordinary quartz sand has some defects such as smooth surface, small specific surface area and poor performance of attach microorganisms. To improve the surface texture of quartz sand and promote microorganism adhesion on the filter, it is an effective method to etch on the quartz sand with buffered oxide etch (BOE). The results of SEM shows that the morphology of the surface reconstructed quartz sand is obviously changed and the global morphology is grooved. Factorial experiment demonstrates that modified quartz sand has more grooves on the surface whose width is between 1.0-5.0 μm and the biomass increases from 9.3 nmol P·g^-1 to 15.7 nmol P·g^-1 after modification, under the condition of corrosive liquid concentration is 15%(mass), the mass ratio of HF and NH₄F is 1:1, the reaction temperature is 55℃, and the reaction time is 45 minutes. The result of FTIR reveals that the Si-O is transformed to Si-OH, the disappearance of organic characteristic peaks indicates the removal of organic material. After the surface modification, surface area of quartz sand increases from 0.427 m²·g^-1 to 1.475 m²·g^-1, and the removal rate of COD_Cr increased from 41.9% to 51.6%. Hence the modified quartz sand has a preferable microbiological compatibility.

Key words: quartz sand, surface reconstruction, preparation, chemical etching, biofilm

摘要：

基于普通石英砂滤料表面光滑、比表面积小、微生物难以附着等缺陷，以BOE（buffered oxide etch）腐蚀液对普通石英砂滤料进行化学蚀刻处理，以改善石英砂的表面形貌，促进微生物在石英砂滤料表面附着。扫描电镜分析结果表明，经改性得到的表面重构石英砂形貌发生明显变化，整体呈沟槽形貌；因素分析试验结果表明，在腐蚀液浓度为15%（质量）、HF与NH₄F的质量比为1∶1、反应温度为55℃、反应时间为45 min的条件下，所得改性石英砂表面的沟槽较多且宽度多介于1.0～5.0 μm之间，表面生物量由改性前的9.3 nmol P·g^-1提高到改性后的15.7 nmol P·g^-1；红外光谱分析结果显示，改性石英砂表面部分Si—O转变为Si—OH，有机物特征峰的消失反映了石英砂表面有机物的进一步去除；石英砂的比表面积由改性前的0.427 m²·g^-1提高至改性后的1.475 m²·g^-1；对COD_Cr的平均去除率由改性前的41.9%提高到改性后的51.6%。因此，表面重构石英砂具有较好的微生物亲和性，更适宜微生物的附着。

关键词: 石英砂, 表面重构, 制备, 化学蚀刻, 生物膜