Removal of Organic Compounds with an Amino Group during the Nanofiltration Process.

Renata Żyłła,Magdalena Foszpańczyk,Stanisław Ledakowicz,Magdalena Olak-Kucharczyk,Joanna Marszałek

doi:10.3390/membranes12010058

Abstract

The research covered the process of nanofiltration of low molecular weight organic compounds in aqueous solution. The article presents the results of experiments on membrane filtration of compounds containing amino groups in the aromatic ring and comparing them with the results for compounds without amino groups. The research was carried out for several commercial polymer membranes: HL, TS40, TS80, DL from various manufacturers. It has been shown that the presence of the amino group and its position in relation to the carboxyl group in the molecule affects the retention in the nanofiltration process. The research also included the oxidation products of selected pharmaceuticals. It has been shown that 4-Amino-3,5-dichlorophenol—a oxidation product of diclofenac and 4-ethylbenzaldehyde—a oxidation product of IBU, show poor separation efficiency on the selected commercial membranes, regardless of the pH value and the presence of natural organic matter (NOM). It has been shown that pre-ozonation of natural river water can improve the retention of pollutants removed.

Highlights

The recent developments in more advanced analytical methods have revealed new threats associated with the presence of various micropollutants in drinking water sources.One of such micro-pollutants are N-nitrosamines (NA)
The presence of an amino group in the aromatic ring reduced the electronegativity of the carboxyl group attached to this ring (PABA, aromatic amines (AAs))
Increasing the pH to 8 caused the dissociation of the carboxyl group and increased the electronegativity of the molecule (PABA, AA, Figure 2B)

Summary

Introduction

The recent developments in more advanced analytical methods have revealed new threats associated with the presence of various micropollutants in drinking water sources. One of such micro-pollutants are N-nitrosamines (NA). Bei et al [2] tested approximately 164 samples of drinking water intended for human consumption in China for the presence of NA. They found that NA concentration in water was much higher in China than in the United States. It has been found that there are many precursors from which NA can be formed during water treatment (e.g., in the process of chlorination and even ozonation) [3,4]

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Results

Conclusion