| With the increased utilization of organic compounds in industry and daily life,the consequent growing discharges of persistent organic pollutants irreversibly affect the environment and potentially threaten human health as well.For example,organic dyes,antibiotics and plasticizer,which are relatively stable in the environment and difficult for degradation.They have toxic effects on aquatic organisms and human beings even at trace concentrations due to the cumulative biological effects.Therefore,it is of great significance and urgent to develop water treatment technologies with high efficiency and low consumption to remove the above mentioned refractory pollutants.The adsorption method is one of the commonly used treatment methods for the removal of organic pollutants,because of low cost,high removal efficiency and eco-friendly.Improving the adsorption performance of catalytic materials can also enhance the pollutants for subsequent degradation.The alloys and transition metal oxides nanoparticles are often used as adsorbents because of their magnetic properties,large specific surface area and well recycle performance.But the nanoparticles are easy to aggregate and affect their adsorption ability.When the nanoparticles are loaded and fixed on some porous materials,this problem could be solved.Titanium dioxide is one of the most common photo-catalysts which used for wastewater treatment since its low cost,non-toxicity,good chemical stability,and light corrosion resistance.It is easy to adsorb,separate and degrade,inhibiting the photoelectric catalytic process after TiO2 combined and fixed with carbon materials.In our work,the metal oxide precursor has been loaded on the pollen carbon by the hydrothermal method,and annealed at different temperatures to generate a composite material of metal oxide and pollen carbon in this study,which can prevent effectively agglomeration caused by small size and magnetism.The XRD patterns of the samples showed that the as-synthesized metal oxides were ?-Fe2O3,CoO,NiO.In the 20 mg/L methyl orange adsorption experiment,the adsorption amount of CoO@C at 500? reached 19.32 mg/g,and the removal rate was 96.61%.Therefore,CoO@C was selected for the adsorption correlation model fitting analysis,which was in line with the secondary reaction.The Pseudo second order kinetic model(R2:0.9683-0.9964),the intra-particle diffusion model and the Freundlich adsorption isotherm model indicate that the adsorption process is the result of both physical and chemical adsorptions,and the judgment is based on electrostatic action.The adsorption and removal efficiency of ciprofloxacin by changing the pH of the reaction is about 80%,so the electrostatic attraction worked,but not the main factor.Recovered by an external magnetic field,the three-time recycling efficiency is still maintained at more than 80%.We have also used activated carbon felt as the substrate and isopropyl titanate as the titanium source to load titanium dioxide on the carbon felt fiber by the in-situ hydrothermal synthesis.The loading amount and size of titanium dioxide particles is affected by changing the dosage of isopropyl titanate(TTIP)and cetyltrimethylammonium bromide(CTAB),as well as the hydrothermal reaction time in the reaction.XRD,SEM,EDS were used to characterize and analyze the crystal morphology and structure.The analysis results showed that the synthesized TiO2 particles are anatase crystals,without obvious impurity peaks,and have high crystallinity.The TiO2 particles are uniformly distributed,without agglomeration,and the size of the particles is about 12.8 nm when the dosage ratio of TTIP:CTAB was 1:1 at 150? for 20 h.The SEM images of the TiO2 growth on the carbon felt shows that the TiO2 nanoparticles are layered on the carbon felt fibers with a certain thickness.The methylene blue was used as target pollutants and the applied voltage of photoelectric catalysis has been tuned.The removal efficiency of methylene blue can reach more than 95%under the conditions of simulated sunlight and 0.8 v voltage within 2h,and it remains at 90%after three cycles used.At the same condition,the maximum degradation efficiency of dimethyl phthalate is 85%after 2h. |
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