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Sorption of Aromatic Ionizable Organic Compounds to Montmorillonites Modified by Hexadecyltrimethyl Ammonium and Polydiallyldimethyl Ammonium
Author(s) -
Xu Huaizhou,
Wan Yuqiu,
Li Hui,
Zheng Shourong,
Zhu Dongqiang
Publication year - 2011
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2011.0161
Subject(s) - sorption , chemistry , sorbent , ammonium , naphthalene , hydrophobic effect , inorganic chemistry , adsorption , organic chemistry
Environmental residues of aromatic ionizable organic compounds (AIOCs) have received considerable attention due to their potential human health and ecological risks. The main objective of this study was to investigate the key factors and mechanisms controlling sorption of a series of anionic and zwitterionic AIOCs (two aromatic sulfonates, 4‐methyl‐2,6‐dinitrophenol, tetracycline, sulfamethoxazole, and tannic acid) to montmorillonites modified with hexadecyltrimethyl ammonium (HDTMA) and polydiallyldimethyl ammonium (PDADMA). Compared with naphthalene (a nonpolar and nonionic solute), all AIOCs showed stronger sorption (the sorbent‐to‐solution distribution coefficient was in the order of 10 3 –10 4 L kg −1 ) to the two organoclays in spite of the much lower hydrophobicity, indicating the predominance of electrostatic interaction in sorption. The proposed electrostatic mechanism of the tested AIOCs was supported by the pH dependency of sorption to the two organoclays. The two organoclays manifested weaker sorption affinity but faster sorption kinetics for bulky AIOCs than commercial activated carbon, resulting from the high accessibility of sorption sites in the open, ordered clay interlayer. The findings of this study highlight the potential of using HDTMA‐ and PDADMA‐exchanged montmorillonites as effective sorbents for AIOCs in water and wastewater treatments.