Study On The Preparation Of NiCo-LDHs/Composites And The Co-Degradation Of Dye Wastewater By Adsorption-Photocatalysis

With the rapid development of Chinese industry,more and more organic dyes are discharged into water bodies,which has caused serious harm to the species and the environment.At present,there are a variety of dye wastewater treatment methods,adsorption method and photocatalysis method has been widely concerned,adsorption method has the advantages of fast and efficient,and photocatalysis method can completely degrade dye wastewater.These two methods are considered the most promising treatment technology.Therefore,in this study,adsorption method and photocatalysis method were combined to study the degradation performance of the catalyst on dye wastewater.In this paper,NiCo-LDHs adsorption materials,NiCo-LDHs/g-C₃N₄ and NiCo-LDHs/g-C₃N₄/WO₃ photocatalytic materials were prepared.The materials were characterized by XRD,FTIR,UV-DRS,SEM,EDS,XPS,TG,PL and BET.The adsorption properties of NiCo-LDHs,the adsorption-photocatalytic properties of NiCo-LDHs/g-C₃N₄ and NiCo-LDHs/g-C₃N₄/WO₃ were systematically studied.The mechanism of material adsorption and photocatalytic degradation of dye wastewater was analyzed,and the recycling property of materials was tested.（1）Three NiCo-LDHs materials were prepared by hydrothermal method.The influence of NiCo-LDHs on the adsorption of methyl orange was studied under different experimental conditions.The results showed that:When the reaction temperature was 25℃,the reaction time was 2 h,the dosage of adsorbent was 1.00 g/L,and the concentration of methyl orange was 5000 mg/L,the maximum adsorption capacity of three NiCo-LDHs for methyl orange was 1001.64 mg/g,1142.07 mg/g and 1003.18 mg/g,respectively.The results show that the three adsorbents have good adsorption capacity,stable physicochemical properties and recycling performance,and the adsorption process is mainly chemical adsorption.（2）Three NiCo-LDHs/g-C₃N₄（hereinafter,LDHs/CN）materials were synthesized by a simple hydrothermal method.The energy gap values of the three materials with different doping ratios are 2.47 eV,2.50 eV and 2.54 eV,respectively.At natural p H,the experimental results showed that the degradation rate of 100 mg/L amaranth（E123）by LDHs/CN was 99.7%when the dosage was 1.00 g/L,which was consistent with the quasi-first-order kinetic model.It was found that h⁺contributed the most to the photocatalytic degradation of amaranth by LDHs/CN.The results showed that LDHs/CN had excellent degradation effect on amaranth,and had good recyclability and stable physicochemical properties.（3）The ultrasonic method was used to compound different proportions of g-C₃N₄ and WO₃,and then compounded on NiCo-LDHs by hydrothermal method,different catalytic materials of NiCo-LDHs/g-C₃N₄/WO₃（hereinafter,LDHs/CN/W）are prepared.The results showed that:（1）At the original p H,the degradation rate of 150 mg/L amaranth reached more than 94%when the dosage of photocatalyst was 1.00 g/L;（2）The degradation rate of LDHs/CN/W was 1.74 times that of LDHs/CN,and the addition of WO₃ improved the photocatalytic degradation performance and degradation rate.The free radical capture experiment and EPR test showed that h⁺,·OH and·O₂^-all contributed to the degradation process.After five cycles,the degradation rate can still reach more than 75%,indicating that it has good cycle stability.