The Study On Adsorption Properties And Wettability Of Imidazolium-based Modified Organo-clays

Imidazolium-based gemini surfactants are a kind of environment-friendly surfactant with varied benefits such as good biodegradability,low irritant and little toxicity.There are theoretical significance and application prospects to develop a new type of highly efficient and environmentally friendly surfactants to modify clay for adsorption of pollutants from water environment.In this work,a series of imidazoline-based gemini surfactants（[C_n-4-C_nim]Br₂,n=12,14,16）were fabricated to prepare organo-vermiculite（C_n-4-C_nim-Vt,n=12,14,16）,organo-Si NSs(C₁₄-4-C₁₄im-Si NSs)and organo-montmorillonite(C₁₄-4-C₁₄im-Mt)without precedent.Imidazolium-based modified Organo-clays were characterized using common methods,their regularity of wettabilities were studied as well.The adsorption experiment results of dimethyl phthalate（DMP）on three organo-Vts(C₁₄-4-C₁₄im-Vt,C₁₂-4-C₁₂im-Vt and C₁₆-4-C₁₆im-Vt)indicated C₁₄-4-C₁₄im-Vt show the most promising adsorbability for DMP(274.4 mg g^-1).The adsorption process turned out to follow the pseudo-second-order and Langmuir isotherm.The adsorption capacitie of organo-Vts follows the order:C₁₄-4-C₁₄im-Vt>C₁₂-4-C₁₂im-Vt>C₁₆-4-C₁₆im-Vt,which appear in a positive correlation with their wettabilities.It means that the adsorption occurs primarily via hydrophobic interaction.Comparative adsorption experiments results of bromophenol blue（BPB）on C₁₄-4-C₁₄im-Vt,C₁₄-4-C₁₄im-Si NSs and C₁₄-4-C₁₄im-Mt demonstrated the adsorption processes are fitting pseudo-second-order kinetics and Langmuir isotherm models.The q_max of organo-Vt,organo-Si NSs and organo-Mt calculated with Langmuir isotherm model are 400.19,230.77 and 220.27 mg g^-1,respectively,which perform a positive correlation with the wettability.The adsorption capacity get higher with lower p H value.It can be concluded that electrostatic and hydrophobic interactions paly critical roles during the process.Besides,C₁₄-4-C₁₄im-Si NSs possesses higher adsorption efficiency(R=99.53%at p H=2,C₀=200 mg L^-1)noticeably.