Study On The Construction Of Photo-responsive Organogels And Their Research On Pilot Experiment Of Sewage Treatment

In the past few years,utilizing self-assembly of the functional small molecules to form supramolecular structures has gradually become an important method for the development of novel materials such as nano-devices.As one of the novel self-assembled soft materials,low molecular weight gelators?LMWGs?can self-assembled to form an ordered three-dimensional network structure through intermolecular hydrogen bonding,interaction,Van der Waals force,and so on,so that organic solvents can be gelatinization.In this paper,we designed and synthesized a novel small molecular organic azobenzene gelator and a detailed study of the adhesive ability of the gel factor in different solvents was be conducted.Besides,we explored the morphology,gelation mechanism of the organic gels and molecular packing structures.Importantly,the organic gels can be limited applied to sewage purification.The full text includes the following two parts:First of all,the design of the target organic gelator based on azobenzene.Azobenzenes,as one of the photo-responsive factors,provide intermolecular?-?interactions.The amide bond connected with azobenzene group by the long alkyl chain provides the intermolecular hydrogen-bond forces,while the long alkyl chain provides Van der Waals force.On the basis of the reported methods,we synthesized efficiently the target molecule Azo-BDOD by pretreating the reaction solvents,optimizing the ratio of reactants,optimizing the reaction time and recrystallization.The obtained organicgelators were characterized by hydrogen nuclear magnetic resonance spectrum?H NMR?and mass spectrometry?MS?to assure the validity of the structures.Secondly,the photophysical properties of Azo-BDOD organogels and the mechanism of organogels were investigated.The organic gelators can form stable organogels with good photoresponsive properties in most organic solvents.Under the irradiation of ultraviolet light and alternative visible light,switching between the gel state and the solution state can be achieved.The organic gelators show solvent dependence.In the apolar solvent,transparent gels are formed with a lower critical gelatinization concentration while opaque gels will be obtained in the polar solvents with a higher critical gelation concentration.The morphology of the self-assembled system also exhibits a strong solvent dependence.The results of infrared and X-ray diffraction analysis indicate that intermolecular hydrogen bonding is the dominant driving force in polar solvents,while in the apolar solvents,?-?interaction force is the main driving force for the formation of Azo-BDOD organgels.Finally,we successfully applied the obtained organogels to the field of pilot of wastewater purification.As a phase-selective organic gelators,Azo-BDOD exhibits the good gelation performance in toluene,and can be used to remove harmful organic solvents such as toluene in the wastewater.Besides,Azo-BDOD gels show an excellent ability of adsorption for Cu²⁺,Cd²⁺,Pb²⁺as well as for the organic dye molecules in the wastewater.particularly,the adsorption efficiency for the rhodamine dye commonly used in the industry is as high as97%.As a potential sewage purification agent,Azo-BDOD gels show limited application prospects.