Surface modification of layered double hydroxides and incorporation of hydrophobic organic compounds

Two sulfonated surfactants, dodecylsulfonate (DSO) and dodecylbenzenesulfonate (DBS), were readily intercalated into MgAl layered double hydroxides (LDHs) using the co-precipitation method. Surface properties of DSO-LDHs and DBS-LDHs were modified from hydrophilic to hydrophobic characteristics. Surfactant aggregates occupying LDHs interlayer regions behaved similarly to that of surfactant micelles. Both DSO-LDHs and DBS-LDHs sorbed the nonionic hydrophobic organic pesticide, chlorpyrifos. Results demonstrate that chlorpyrifos was successfully retained in the hydrophobic region of DSO-LDHs and DBS-LDHs, with two distinct interlayer conformations. The nature of chlorpyrifos and surfactants, and supramolecular structure of surfactant-modified LDHs were responsible for differences in the conformations resulting from pesticide-incorporated LDHs.