The efficient removal of dimethyl phthalate by three organo-vermiculites with imidazolium-based gemini surfactants in aqueous media

摘要

Imidazolium-based gemini surfactants were attracted extensive attention in recent years with varied benefits such as good biodegradability, low irritant and little toxicity. In this paper, a series of imidazolium-based gemini surfactants with a four-methylene spacer and long hydrophobic chains ([C-n-4-C(n)im]Br-2, n = 12, 14, 16) were fabricated for modification of vermiculite. The primary characterization of organo-vermiculites (OVts) like Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TG-DTG), scanning electron microscope (SEM), wettability and Elemental Analysis were carried out. The resultant OVts were used to remove dimethyl phthalate (DMP) from aqueous solution, particularly C-14-4-C(14)im-Vt showed the most promising adsorbability (274.4 mg g(-1)) which is efficient comparing with other adsorbents. The adsorption processes turned out to follow the pseudo-second-order and Langmuir isotherm. Furthermore, the wettabilities of OVts followed the order: C-14-4-C(14)im-Vt > C-12-4-C(12)im-Vt > C-16-4-C(16)im-Vt, which appeared in a positive correlation with the adsorption capacities. Draw a conclusion the sorption occurred primarily via hydrophobic interaction and pi-pi interaction between OVts and DMP. C-14-4-C(14)im-Vt could be favorably reproduced by ethanol at least for five cycles. It provides some new thoughts for the possibility of design and synthesis of OVts as high-efficiency adsorbents.