Probing Membrane Fouling via Infrared Attenuated Total Reflection Mapping Coupled with Multivariate Curve Resolution

Abstract

Understanding membrane fouling induced by dissolved organic matter (DOM) is of primary importance for developing effective fouling control and prevention strategies. In this work, we combine multivariate curve resolution-alternating least squares analysis with infrared attenuated total reflection mapping to explore the fouling process of microfiltration and ultrafiltration membranes caused by two typical DOMs, humic acid (HA) and bovine serum albumin (BSA). The spectral contributions of different foulants and the membrane substrate were successfully discriminated, thereby enabling the diagnosis of fouling origins. Membrane fouling caused by HA is more severe than that by BSA. Three periods, the initial adsorption stage, the equilibrium stage, and the accumulation stage, were observed for the HA-induced fouling process. The integrated approach presented herein elegantly demonstrates the spatial and temporal characterization of membrane fouling processes, along with relative concentrations of the involved species, and suggests a promising perspective for understanding the interaction mechanisms between foulant species and membranes at the molecular level.

Functional Determinants of Extracellular Polymeric Substances in Membrane Biofouling: Experimental Evidence from Pure-Cultured Sludge Bacteria

“…Analysis of purified EPS from each sludge bacterial species using Fourier transform infrared spectroscopy (FTIR) helps in distinguishing the environmental isolates based on their fouling potentials (18). EPS contains charged functional groups (e.g., carboxyl and hydroxyl groups) and polar groups (e.g., aliphatics and aromatics) (19)(20)(21).…”

Molecular Spectroscopic Characterization of Membrane Fouling: A Critical Review

“…ATR-IR mapping coupled with multivariate curve resolutionalternative least squares (MCR-ALS) analysis allows for the discrimination of fouling origin, spatial and temporal characterization of fouling evolution, and recognition of fouling propensities of different foulants (Figure 5B). 22 The porosity of the membrane can also be evaluated by IR mapping. A recent work has shown that the bulk porosity of the membrane was rather homogeneous, and the surface porosity was characterized by systematic local deviations from its mean value up to about 30%.…”

“…Some of them, e.g., microspectroscopic techniques, can even give the 3D spatial and temporal distribution of specific foulants. [21][22][23] Despite some limitations, such as labeling, sensitivity, and time cost, spectroscopic methods are among the most efficient platform tools for characterizing membrane fouling with the ultrafast development of spectroscopic instrumentation and chemometric approaches for spectral data treatment.…”

“…ATR-FTIR Spectra of BSA, HA, and EPS Foulants Spectral range: 1,750-750 cm À1 . Reprinted with permission from Chen et al22 Copyright 2016 Wiley-VCH Verlag GmbH & Co. KGaA.…”

Quantitative analysis and resolution of pharmaceuticals in the environment using multivariate curve resolution-alternating least squares (MCR-ALS)

“…It decomposes the data matrix into a bilinear model producing pure spectral and concentration profiles of the mixture components. The algorithm has been successfully used to analyze data coming from different sources such as IR (14), chromatography (15), hyperspectral imaging (16), nuclear magnetic resonance (17) and X-ray fluorescence (18). Parastar and Shaye (19) applied the algorithm to spectrophotometric determination of some pharmaceuticals in different water samples.…”