Preparation Of Imidazoline Periodic Mesoporous Organosilicas And It's Application In Treatment Of Wastewater And Proton Conduction

Due to the carcinogenic effect,the removal of organic dyes and chromium(?)from printing,dyeing and electroplating wastewater has become an urgent problem that should be solved in environmental management.Adsorption as the key technology of wastewater treatment,has attracted much attention because of the advantages of convenience,low cost,and simple operation.However,the smaller channels and difficulty in perform functional modification have made commercial activated carbon limited capacity of big organic dye and poor selectivity.Therefore,it is extremely urgent need to find new materials with larger pore sizes,larger specific surface areas,and flexible structure control as adsorbents for wastewater treatment.In this paper,the imidazolinium-based ionic liquid silicate(IML-Si)and TEOS are used together as the silicon source,keeping the total number of moles of silicon source is the same,and the proportion of IML-Si in the total silicon source is adjusted and synthesized by the sol-gel method.Five cationic periodic mesoporous organosilica have be synthesized as follows:5%IML-PMO,10%IML-PMO,15%IML-PMO,20%IML-PMO,and 25%IML-PMO.We found that with the proportion of IML-Si increasing,resulted in decrease of the specific surface area as well as increase of the cation sites.Consequently,the adsorption effect on anionic pollutants increase before decrease.Among them,20%IML-PMO has a far greater adsorption capacity than the current commercial activated carbon for the anionic azo dye Congo red.The maximum saturated adsorption capacity is 1135 mg/g.Also,the adsorption rate is very fast that can get adsorption equilibrium within 22 min.The material also can be packed in the column to simulate the purifiction of Congo red wastewater.For example,200 mg/L Congo red wastewater can be reduced to less than 0.1 mg/L with 20 mg IML-PMO 20%column,which can meet GB 4287-2012 on the direct emission of industrial wastewater standards.The theoretical investigation of the adsorption process conforms to the Langmuir isothermal adsorption model and the pseudo-second-order kinetic model.The maximum saturated adsorption capacity of Cr(?)up to 44.6 mg/g can reach adsorption equilibrium within 20 min.which conforms to langmuir isothermal model and pseudo-second-order kinetic model.In addition,we also used this material to immobilize phosphotungstic acid so as to obtain PTA@IML-PMO,a material with high proton conductivity.Its proton conductivity reached 1.2×10-4 S/cm.which is two orders of magnitude higher than PTA@SBA-15 obtained by mesoporous silica immobilize phosphotungstic acid.