HUANGXiaoyi,BAIFubiao,WANGXinglin,et al.Development of Ornithine-based Nanofiltration Membranes for Selective Separation of Organic Matter and Minerals[J].China Water & Wastewater,2026,42(5):47-54.
Development of Ornithine-based Nanofiltration Membranes for Selective Separation of Organic Matter and Minerals
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第42卷
Number:
第5期
Page:
47-54
Column:
Date of publication:
2026-03-01
- Keywords:
- drinking water; nanofiltration membrane; ornithine; natural organic matter; minerals; selective separation
- Abstract:
- The fabrication of nanofiltration (NF) membranes capable of selectively separating minerals from natural organic matter (NOM) holds significant importance for drinking water treatment. Conventional polyamide NF membranes (CIP), typically synthesized via interfacial polymerization (IP) using piperazine (PIP) as the aqueous monomer and trimesoyl chloride (TMC) as the organic monomer, generally lack selectivity. While effectively removing organic pollutants, they also retain beneficial divalent cations such as Ca2+ and Mg2+. To address this, an NF membrane featuring a strongly electronegative and loosely structured polyamide (PA) layer was developed. This was achieved by employing ornithine (Orn)—an amino acid with a flexible aliphatic chain—as the sole aqueous monomer, reacting with TMC on a polyethersulfone support membrane via IP. The resulting ornithine-based NF membrane (Orn-NF) was designed for the efficient selective separation of minerals (e.g., Ca2+, Mg2+) and NOM (e.g., humic acid, sodium alginate). The membrane was characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The results indicated that during amidation, the α-amino group of Orn experiences steric hindrance from its adjacent α-carboxyl group. This likely led to a lower cross-linking density in the PA layer compared to the CIP membrane, facilitating the formation of a more open structure. Furthermore, Orn introduced additional carboxyl groups (—COOH), enhancing the overall electronegativity of the PA layer and promoting the permeation of positively charged ions. Consequently, the Orn-NF membrane demonstrated remarkable separation performance: high permeation of minerals (retention rates of 6.34% to 15.34% for Ca2+ and Mg2+) coupled with high rejection of NOM (retention rates >98% for humic acid and sodium alginate). The membrane also exhibited excellent permeability and operational stability.
Last Update:
2026-03-01