UPTAKE OF SUBSTITUTED NAPHTHALENES FROM AQUEOUS SOLUTIONS BY LAYERED DOUBLE HYDROXIDES INTERCALATED WITH AROMATIC SULFONATES

摘要

Mg-Al and Cu-Al layered double hydroxides (LDHs) intercalated with 1-naphthol-3,8-disulfonate (1-N-3,8-DS2), i.e., 1-N-3,8-DS*Mg-Al LDH and 1-N-3,8-DS*Cu-Al LDH, and Mg-Al LDH intercalated with benzenesulfonate (BS ), i.e., BS*Mg-Al LDH, show preferential uptake of 1-nitronaphthalene (NN), 1-chloronaphthalene (ClN), and 2,7-dimethoxynaphthalene (DMN) over naphthalene (N) from solutions. In the case of NN and ClN uptake, k-k stacking interactions are considered to occur between the electron-poor naphthalene ring of NN and ClN and the electron-rich naphthalene and benzene cores of intercalated 1-N-3,8-DS2— and BS— in the LDHs. In the case of DMN uptake, CH/兀 interactions are considered to occur between the electron-poor CH of the OCH3 groups in DMN and the electron-rich naphthalene and benzene cores of intercalated 1-N-3,8-DS2— and BS— in the LDHs. On the other hand, the uptake of N is attributed to hydrophobic interactions between the naphthalene ring of N and the naphthalene and benzene cores of intercalated 1-N-3,8-DS2— and BS— in the LDHs. Thus,兀-兀 stacking and CH/兀 interactions are a stronger driving force than hydrophobic interactions, resulting in preferential uptake of substituted naphthalenes by 1-N-3,8-DS*Mg-Al LDH， 1-N-3,8-DS*Cu-Al LDH; and BS*Mg-Al LDH.