Preparation Of LDHs/molybdenum-based Micro/nano Composite Photocatalyst Based On Biological Template And Its Properties

In recent years,adsorption and photocatalysis have been widely used in the field of sewage treatment.Hydrotalcite?LDHs?can be used in the adsorption field because of their high specific surface area and interchange of interlayer anions.In addition,the calcined product CLDH of LDHs has photocatalytic activity for organic contaminants in wastewater,and therefore can be used in the field of photocatalysis.However,there are many problems with LDHs,such as easy aggregation between sheets,poor recovery after use and poor photocatalytic performance.Therefore,LDHs are combined with biological templates and molybdenum-based photocatalyst to improve the problems of LDHs.1.The MoS₂/CoAl-LDH/HCF micro-nanotubes were successfully prepared by using kapok as the biological template.The microstructure and physical properties of MoS₂/CoAl-LDH/HCF were analyzed by SEM,TEM,XRD,FT-IR,Uv-vis diffuse reflection and N2 adsorption-desorption.The results showed that MoS₂/CoAl-LDH/HCF had maintained the microstructure of kapok and had a porous structure with a specific surface area of 201.98 m2 g-1.Then,the adsorption properties of Congo red were studied.Adsorption experiments showed that the prepared MoS₂/CoAl-LDH/HCF exhibited excellent adsorption properties.The maximum adsorption capacity of MoS₂/CoAl-LDH/HCF reached 497.51 mg g-1.The adsorption process was in accordance with the pseudo-second-order kinetic model and the Langmuir model,and the adsorption process was spontaneous endothermic reaction.The MoS₂/CoAl-LDH/HCF had good reusability.Finally,the photocatalytic performance of Congo red was studied.The photocatalysis experiment showed that MoS₂/CoAl-LDH/HCF exhibited good photocatalytic activity for Congo red under the visible light irradiation,and its degradation process was in accordance with the pseudo-first-order photocatalytic kinetic equation.The photocatalytic performance of MoS₂/CoAl-LDH/HCF was better than those of MoS₂ and CoAl-LDH,and the MoS₂/CoAl-LDH/HCF had good reusability.2.Bi₂MoO₆/ZnAl In-LDH composites were successfully synthesized by using absorbent cotton as template.The microstructure and physical properties of Bi₂MoO₆/ZnAlIn-LDH were analyzed.The results showed that ZnAl In-LDH and Bi₂MoO₆ were uniformly supported on the surface of alumina fiber,and the sample retained the hollow tubular microstructure of the original cotton.Then,the adsorption properties of doxycycline were studied.Comparing the adsorption properties of Bi₂MoO₆/ZnAlIn-LDH prepared by Bi₂MoO₆ with different contents and different pH values,the best Bi₂MoO₆ preparation conditions were as follows: n?Bi₂MoO₆?=0.1 mmol,pH?Bi₂MoO₆?=7.Adsorption experiments showed that the prepared Bi₂MoO₆/ZnAl In-LDH exhibited excellent adsorption properties.The maximum adsorption capacity of Bi₂MoO₆/ZnAlIn-LDH was 267.38 mg g-1,and the adsorption process was in accordance with the pseudo-second-order kinetic model and Langmuir model.The adsorption process was a spontaneous endothermic reaction,and the prepared Bi₂MoO₆/ZnAlIn-LDH adsorbent could be reused.3.The Bi₂MoO₆/ZnAlIn-CLDH was successfully prepared by high temperature calcination of Bi₂MoO₆/ZnAlIn-LDH.The microstructure and physical properties of Bi₂MoO₆/ZnAl In-CLDH were analyzed.From the XRD analysis,the diffraction peaks of ZnAlIn-LDH disappeared and converted to ZnO and In2O3.It could be seen from SEM and TEM that the sample retained the hollow tubular morphology of the biological template,and ZnAlIn-CLDH retained the lamellar morphology of ZnAlIn-LDH.Then,the adsorption properties of Bi₂MoO₆/ZnAlIn-CLDH to doxycycline were studied.The adsorption experiments showed that the prepared Bi₂MoO₆/ZnAlIn-CLDH had excellent adsorption properties to doxycycline.The adsorption process was in accordance with the pseudo-second-order kinetics model,and the adsorption process was spontaneous endothermic reaction.The prepared Bi₂MoO₆/ZnAl In-CLDH could be reused.Finally,the photocatalytic performance of Bi₂MoO₆/ZnAlIn-CLDH on doxycycline was studied.The photocatalytic experiments showed that Bi₂MoO₆/ZnAlIn-CLDH had good photocatalytic performance for doxycycline under visible light irradiation.The degradation process of Bi₂MoO₆/ZnAl In-CLDH was consistent with the pseudo-first-order photocatalytic kinetic equation.The photocatalytic performance of Bi₂MoO₆/ZnAlIn-CLDH was superior to those of pure Bi₂MoO₆ and Zn AlIn-CLDH,and the prepared photocatalyst had good reusability.