Preparation And Adsorption Properties Of Gemini Modified Silica Nanosheets

Adsorption is a common sewage treatment method which is efficient,cheap,environmentally friendly,low in energy consumption and easy to operate.As an emerging adsorption material,organo silica nanosheets has attracted much attention from scholars because of its fast adsorption rate,large adsorption capacity and low cost compared with traditional adsorption materials.In this study,organo silica nanosheets（organo-Si NSs）with different chain lengths(G_8-2-8-Si NSs,G_12-2-12-Si NSs and G_16-2-16-Si NSs)and different spacer lengths(G_16-2-16-Si NSs,G_16-3-16-Si NSs,G_16-4-16-Si NSs and G_16-6-16-Si NSs)were prepared and characterized.The effect of the structure of gemini on the adsorption characteristic of organo silica nanosheets（organo-Si NSs）toward ibuprofen and rhodamine B was investigated.The experimental results show the longer alkyl chain length favors the organic modification process.The adsorption of ibuprofen on the organo silica nanosheets with different chain lengths indicates that the longer the alkyl chain length of the organic silica nanosheets,the greater the adsorption amount of ibuprofen.Adsorption capacity of ibuprofen onto G_16-2-16-Si NSs reached 64.19 mg g^-1 at a low dosage of surfactant（2CEC）,and the adsorption equilibrium was reached in 5 minutes.In addition,electrostatic interactions and hydrophobic interactions play an important role in the adsorption process.It was found that the shorter spacers facilitate the intercalation of gemini surfactants into the layers of silica nanosheets,which is beneficial to the modification process.However,the adsorption of rhodamine B onto organic silica nanosheets decrease in the dominant role in adsorption,and electrostatic interactions and competitive adsorption also affect the adsorption of Rhodamine B.The optimal adsorption conditions,adsorption kinetics and thermodynamics of organic silica sheets with different chain lengths and different spacer lengths were also investigated.Furthermore,organo silica nanosheets exhibit excellent regenerative properties.