摘要
污水再生利用是解决水资源短缺问题的有效对策。纳滤技术由于能够生产高质量的再生水,成为污水深度处理、再生利用的有效方法之一。然而,在纳滤过程中存在复杂的、动态的膜污染现象,会导致产水通量、产水质量下降等问题。研究膜污染动态发展的行为,对于膜污染的分阶段针对性控制具有重要意义。有机物是污染层动态发展过程的重要指示性成分,红外光谱是表征污染层发展过程中表面有机物官能团变化情况的重要手段。但由于红外光谱中峰的数量多,系列样品之间峰强度的差别较小(尤其是当膜污染过程中的采样间隔较小时),利用直观观察不易甄别不同样品间的谱图差异及其变化趋势,在此水平上难以对膜污染阶段进行准确识别、对各阶段特征进行有说服力的分类概括。为探索膜污染的动态发展过程,本研究将傅里叶变换红外光谱与统计学聚类分析相结合,对膜污染过程中不同时间点的膜样本进行红外光谱分析,再对红外光谱数据进行一系列预处理和系统聚类分析,从而客观解读膜污染动态发展过程中系列样品红外光谱分阶段变化规律。考虑到类别间距离度量方法、红外吸收峰强度标准化、峰之间自相关性、峰与样本之间交互作用等因素的影响,研究采用对应分析对红外数据进行预处理,提取各样本在主要维度上的得分,随后基于标准化欧式距离对各样本进行聚类。在为期一个月的城市污水深度处理纳滤试验过程中,由于污染物在膜表面累积,纳滤膜发生了较为严重的污染。通过对13个不同时间点的膜样本进行红外光谱聚类发现,膜污染可清晰划分为如下阶段:空白膜、阶段Ⅰ(3h～8d)、阶段Ⅱ(10～15d)和阶段Ⅲ(20～30d)。采用红外聚类,得到膜表面X射线光电子能谱(XPS)和三磷酸腺苷(ATP)含量分析等方法的交互验证。结果表明,随着膜污染的发展,�
Sewage reclamation is one of the effective countermeasures for solving the water shortage problem.Nanofiltration(NF)process is an effective method for reclaiming secondary effluent since it can provide high-qualitied water.However,during the nanofiltration process,complicated and dynamic membrane fouling occurred,which can cause the decrease in flux and effluent quality.Tracking the dynamic evolution of NF membrane fouling in water treatment is important for controlling the membrane fouling depending on different fouling stages.Organic matters are important indicative contaminant for the dynamic evolution of fouling layer.Attenuated total reflectance-Fourier transform infrared spectroscopy(ATR-FTIR)is one of the most significant methods to characterize the change of functional groups in fouling layer.However,the peaks of ATR-FTIR are complex and the variations between different samples are tiny,especially when the fouled membrane samples are similar in time.It is difficult to directly discriminate the variation and trend of different ATR-FTIR spectra and cannot be the convictive evidence for fouling stages recognition.To investigate the dynamic evolution of membrane fouling,this study categorized the NF membranes samples obtained at different fouling time through combining the ATR-FTIR spectra and clustering analysis.Considering the influence of distance measurement method between categories,normalization of ATR-FTIR peak absorbance,correlation between peaks,and interaction between peaks and samples,this study utilized the correspondence analysis as the pretreatment of the ATR-FTIR spectra to obtain the scores of different membrane samples along main dimensions and then clustered the samples based on normalized Euclidian distance.During the 1-month NF experiment using sewage secondary effluent,because of the deposition of foulants,membrane fouling occurred and 13 fouled membranes were obtained at different time.Based on the hierarchical clustering of ATR-FTIR spectra,the fouling process can be clearly divided int
作者
李梦晨
肖康
黄霞
LI Meng-chen;XIAO Kang;HUANG Xia(State Key Joint Laboratory of Environment Simulation and Pollution Control,School of Environment,Tsinghua University,Beijing00084,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2019年第2期421-427,共7页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(51678336)资助
关键词
红外光谱
聚类分析
纳滤膜污染
动态发展
ATR-FTIR spectra
Clustering analysis
Nanofiltration membrane fouling
Dynamic evolution
