脱膜剂对石英砂表面活性滤膜脱膜效果比较

Comparisons of the film peeling from the quartz sands filter using film peeling solvents

为解决水厂滤池反冲洗周期逐渐缩短的问题,利用HCl、Na_2SO_3与H_2O_(23)种脱膜剂,对表面滤膜过度增长的石英砂活性滤料进行静态脱膜实验,确定最适脱膜剂投量与脱膜时间,应用于中试动态过滤系统中.利用扫描电子显微镜(SEM)与X射线荧光光谱分析(XRF)对脱膜前后滤料进行微观表征.结果表明:静态实验确定HCl的最适投量为14.6 mg/g,Na_2SO_3与H_2O_2的最适投量均为11.7 mg/g,3种脱膜剂最适脱膜时间均为40 min;中试系统经脱膜剂处理后,滤层空隙率与反冲洗周期均明显提高,HCl脱膜效果尤其突出,经HCl处理后,滤层空隙率由脱膜前的27.7%提高至39.1%,反冲洗周期由脱膜前的33.7 h提高至61.6 h;同时,滤柱内石英砂滤料催化氧化活性并未受到影响,出水水质仍稳定达标.SEM及XRF表征结果表明,滤料表面的滤膜被部分剥离,滤膜表面形貌与元素组成均无明显变化.综合考虑反冲洗周期恢复效果与经济因素,HCl为最优的脱膜剂选择.

To solve the problem of backwashing interval shortness of water plants, several film peeling solvents including HCl, Na2 SO3 and H2 O2 were examined to peel off the overgrown filter film from filter sands surface. An optimized dosage and time were determined by batch tests. Subsequently, the optimized conditions were tested in the pilot-scale columns. The filter sands before and after treatment were characterized by scanning electron microscopy （ SEM ） and X-ray fluorescence spectroscopy （ XRF ） . The results demonstrated that the optimized dosage and time by HCl peeling were found to be 14.6 mg/g film and 40 min, and they were 11.7 mg/g film and 40 min for both Na2 SO3 and H2 O2 . After treatment by the film peeling solvents, the backwashing interval could be efficiently recovered. Especially for HCl, the bed voidage increased from 27. 7% to 39. 1%, and the backwashing interval increased from 33.7 h to 61.6 h. At the same time,the catalytic oxidation activity was not affected by the peeling, and the water quality of effluent was still lower than the permitted limit. From the results of SEM and XRF, the morphologies and elements of some films were rarely changed. Considering the recovery of the backwashing interval and economic factors, HCl is a suitable choice for peeling off the filter film.