The Study On Wettability And Adsorption Of Different Layer Charged Clays Modified By Organic Modifiers

Layer charge is indentified as one of the most important characters of clay mineral,which has significantly effect on wettability and adsorption capacity.It could provide theoretical guidance and enlightenment significance for developing the efficient organo-clay adsorbent by exploring the wettability alteration of high layer charged clay as well as the adsorption capacity of clays with different layer charge.In this work,organo-clays were prepared and characterized,the wettability alteration of organo-clays was explored,and the adsorption capacities of different layer charged organo-clays toward Congo red were also studied,and adsorption kinetics,isotherms and thermodynamics parameters were also explored..The results of the study are as follows:(1)Four surfactants(HM,DM,HBP and DBP)were employed for modifying vermiculte and reduced-charge vermiculite.The XRD,FT-IR and TG results of organo-clays indicated that organo monolayer has been formed between layers and resulted in a water repelling surface.As the results of capillary rise experiments,the wettability of organo-Vts manifested an M-shaped tendency with the layer charge decreasing.Difference in structure of surfactants led to the sequence of wetting properties: DM-Vts > DBP-Vts > HBP-Vts > HM-Vts.Among those factors,layer charge took a decisive position in wettability alteration.(2)Vermiculite,montmorillonite and silica nanosheets with diminishing layer charge were modified by a novel ether-spacer-containing Gemini surfactant(BDEE).The results of XRD,FT-IR and TG indicated that the BDEE in vermiculite,montmorillonite and silica nanosheets adopted different arrangements.The adsorption experiments of Congo red on the three organo-clays were explored,and the results showed that the saturated sorption amount of BDEE-Vt,BDEE-Mt and BDEE-SiNSs up to 298,154 and 64 mg/g at 55 ? within 120 min,respectively.And the order ofadsorption capacities of these organo-clays was agreed with the sequences of the layer charge and the hydrophobicity of particles.What's more,the results of adsorption kinetics,isotherms and thermodynamics of Congo red adsorption indicated that the pseudo-second-order and Redlich-Peterson models were more suitable for the Congo red adsorption of three adsorbents.The processes of absorbed CR on BDEE-Vt and BDEE-Mt were endothermic and spontaneous,while BDEE-SiNSs was endothermic and non-spontaneous converted to spontaneous with temperature increasing.