Preparation Of Fe-Co Based Nanomaterials And Study On Adsorption Efficiency And Mechanism Of Rhodamine B

Dye wastewater discharge is in the forefront of global wastewater discharge,posing a serious threat to human health and ecological security.Dyes belong to aromatic compounds with complex structures,which are difficult to remove and degrade due to their toxicity,diffusibility and stability,and will not only damage phytoplankton and other aquatic plants,but also harm human beings.Rhodamine B(RhB),as one of the main substances in dye wastewater,a kind of jaundice dye,which can cause irritation,carcinogenicity and reproductive and developmental toxicity to human and animal skin,eyes and respiratory tract.The COD value of dye wastewater is very high,but the BOD value is very low,and the biodegradability of the wastewater is very poor,which makes it difficult for the traditional method to treat it effectively.Adsorption method can achieve the effect of advanced removal by adding porous materials such as activated carbon and clay and some nano-composite materials to the wastewater.Adsorption method is widely used in dye wastewater treatment because of its simple operation and strong adsorption capacity.In this study,many methods were explored to prepare Fe-Co-based nanomaterials,and its properties were optimized by doping S,Moand Nielements.SEM,EDS,XRD,BET,FTIR and other characterization methods were used to analyze the morphology and structure of the material;Many experiments were designed to study the adsorption performance of Fe-Co-based nanomaterials on printing and dyeing wastewater by changing the dosage of adsorbent,pH value of wastewater and environmental temperature,kinetics and isothermal model were used to study the adsorption process and mechanism.The main research contents and conclusions of this paper are summarized as follows:(1)Granular FeCoS nanomaterials were prepared and their adsorption properties for rhodamine B(RhB)were studied.Through the characterization and analysis of SEM,EDS,XRD,BET and FTIR,it is proved that FeCoS nanomaterials have good crystal structure and purity.Several groups of experimental studies show that when the temperature is45?,the concentration of FeCoS is 20 mg,pH=7,the concentration of RhB is 10 mg/L,the saturated adsorption capacity of FeCoS is 578.03 mg/g,and the adsorption equilibrium can be reached in 150 min.The adsorption of Rhodamine B by FeCoS is controlled by chemical adsorption,which is uniform monolayer adsorption,because the kinetic adsorption process conforms to the quasi-second order model and the isothermal adsorption model conforms to Langmuir;temperature studies show that the adsorption process is a spontaneous endothermic reaction.FeCoS can be recycled,according to the results of five cycles of experiments.(2)In view of the long adsorption equilibrium time of FeCoS nanomaterials to Rhodamine B solution,irregular spherical FeCoMoS nanomaterials were prepared.The characterization of SEM,EDS,XRD,BET and FTIR shows that FeCoMoS nanomaterials exhibit irregular spherical special morphology,good crystal structure and high purity,In FTIR analysis,the peak at 768 cm^-1shows the stretching vibration of Mo-O,and a new absorption peak appears near 676 cm^-1,which belongs to the stretching vibration of Fe-O.The adsorption experiments show that when the temperature is 45?,the dosage of FeCoMoS is 20 mg,pH=7,the concentration of RhB is 10 mg/L,the q_mof FeCoMoS is280.89 mg/g,and the equilibrium can be reached within 35 min,the adsorption equilibrium time is shorten,and the material has good removal efficiency under acidic and weak alkaline conditions.The adsorption belongs to homogeneous monolayer adsorption,which is mainly controlled by chemical adsorption according to the quasi-second order kinetic model and Langmuir model.It is known from temperature study that the adsorption process is a spontaneous endothermic reaction.After recycling research,the removal rate of the material is 88.64%when it is used for the fifth time,which indicates that the adsorbent has certain recycling ability.(3)Combining the advantages of FeCoS nanomaterials and FeCoMoS nanomaterials,spherical FeCoNiS nanomaterials with high capacity and fast adsorption were prepared,and their adsorption properties for Rhodamine B were studied.The characterization methods of SEM,EDS,XRD,BET and FTIR show that FeCoNiS nanomaterials show special spherical morphology,high purity and good crystal structure,the Ni-S bond peak at624cm^-1in FTIR proves the existence of chalcogenides.And the adsorption experiments under different influencing factors show that when the temperature is 45?,the concentra-tion of FeCoNiS nanomaterials is 25 mg,pH=7,the concentration of RhB is 10 mg/L,the q_mof FeCoNiS nanomaterials is 581.4 mg/g,and the adsorption equilibrium is reached within 15 min.The adsorption process of FeCoNiS nanomaterial to Rhodamine B can be fully reflected by kinetic quasi-second order model and isothermal Langmuir model,indicating that the adsorption is chemical adsorption and belongs to monolayer uniform adsorption;reaction temperature studies show that the adsorption process is a spontaneous endothermic reaction.In the five-cycle regeneration study,the removal rate of adsorbent decreased from 99.46%to 85.92%,and the efficiency decreased by 13.6%.It is concluded that adsorbent has certain recycling ability.