Preparation And Properties Of G-C₃N₄/C And G-C₃N₄/S-ZnO Composites By Cellulose/lignin

With the vigorous development of biomass research in recent years,the utilization of plant resources has gradually evolved from the simple application of traditional macro materials to the reprocessing of micro chemical components.The main components of plants are cellulose,lignin and hemicellulose,and their recyclable and non-polluting properties make them become the important chemical raw materials.Complementing the advantages of materials science,physics,chemistry,etc.are the fundamental means of giving high value-added biomass.This paper focuses on the new semiconductor material carbon nitride?g-C₃N₄?.with the advantages of its high visible light responsiveness and chemical stability,combined the functions of cellulose and lignin to synthesize superior performance nanomaterials through compounding and doping.The experimental results confirmed that the quantum dots prepared by cellulose and g-C₃N₄ have wider luminescence wavelength and relatively stronger fluorescence intensity,and can be used as an ion detection probe for Fe3+.On the other hand,we use cellulose/lignin to assist g-C₃N₄ to prepare photocatalysts,organic pollutants in water replaced by phenol and methylene blue?MB?,and evaluate the photocatalytic properties of composites by degrading them.Details are as follows:?1?Cellulose and g-C₃N₄ were used to prepare a new type quantum dots named as g-C₃N₄-Carbon dots?CN-CDs?by hydrothermal reaction in an acidic atmosphere.The quantum efficiency of CN-CDs and cellulose derived carbon quantum dots?CDs?was compared by the reference method.In order to determine the optimal synthesis route,the effects of precursor type,reaction temperature,reaction time and pH on the performance of CN-CDs were discussed respectively.In addition,X-ray diffraction?XRD?and X-ray photoelectron spectroscopy?XPS?were used to confirm that the quantum dots contained the g-C₃N₄ and graphite;The functional groups and crystallization degree of CN-CDs were analyzed by Fourier transform infrared spectroscopy?FTIR?and Raman spectroscopy?Raman?.The morphology and structure of CN-CDs were characterized by transmission electron microscopy?TEM?.Finally,the metal ions with fluorescence quenching properties of the CN-CDs,so they were applied to detect Fe3+ion,and the minimum detection limit was calculated.?2?On the basis of preparation of CN-CDs quantum dots,solid products separated and purified in the experiment were collected,named as g-C₃N₄/C photocatalyst.The phase composition of g-C₃N₄/C were analyzed XRD and XPS.In addition,the influence of reaction temperature on the micro-morphology of g-C₃N₄/C was analyzed by SEM and TEM,and the results showed that the dispersiom of the sample was better with the increase of temperature.The photocatalytic capacities of g-C₃N₄/C prepared at different temperature,pure g-C₃N₄ and C were investigated by phenol and MB photodegradation experiments.The results show that g-C₃N₄/C-140 has the best performance which was prepared at 140?,and its degradation efficiency of MB can reach 96%under visible light irradiation.?3?g-CaN4/S-ZnO?CNSZ?material were prepared by one-pot method using sodium lignosulfonate?SLS?.Through the analysis of XRD,EDS and XPS of CNSZ,it was found that g-C₃N₄ and ZnO phase existed in the composite,and S element was also doped into the crystal structure of ZnO.The effect of alkalinity on the performance of CNSZ was discussed by regulating the concentration of NaOH?1?4 mol·L-1?in the preparation process,and the catalytic capacity of CNSZ was explored through the photodegradation experimental of phenol and MB.