Zirconyl-molybdopyrophosphate-tributyl phosphate （ZMPP-TBP） was a novel organic-inorganic composite adsorbent prepared by co-precipitation method and used in the adsorption of uranium from aqueous solution in batch adsorption experiments The as-obtained product was characterized using SEM, energy dispersive X-ray spectroscopy （EDX）, XRD and BET-N2 ad- sorption measurements. The study had been conducted to investigate the effects of solution pH, temperature, contact time, ini- tial concentration and coexisting ions. A maximum removal of 99.31% was observed for an initial concentration 5 mg/L, at pH 6.0 and an adsorbent dose of 1.0 g/L. The isothermal data were fitted with both Langmuir and Freundlich equations, but the data fitted the former better than the latter. According to the evaluation using the Langmuir equation, the maximum adsorption capacity of uranium （VI） was 196.08 mg/g at 293 K and pH 6.0. The pseudo-first-order kinetic model and pseudo-second-order kinetic model were used to describe the kinetic data, and the pseudo-second-order kinetic model was better. The thermody- namic parameter AG was calculated, the negative AG values of uranium （VI） at different temperature showed that the adsorption process was spontaneous. The good reusability of ZMPP-TBP also indicated that the ZMPP-TBP was a very promising adsorbent for uranium adsorption from aqueous solution.
Constructing nanocomposites that combine the advantages of composite materials,nanomaterials,and interfaces has been regarded as an important strategy to improve the photocatalytic activity of TiO2.In this study,2D‐2D TiO2 nanosheet/layered WS2(TNS/WS2)heterojunctions were prepared via a hydrothermal method.The structure and morphology of the photocatalysts were systematically characterized.Layered WS2(~4 layers)was wrapped on the surface of TiO2 nanosheets with a plate‐to‐plate stacked structure and connected with each other by W=O bonds.The as‐prepared TNS/WS2 heterojunctions showed higher photocatalytic activity for the degradation of RhB under visible‐light irradiation,than pristine TiO2 nanosheets and layered WS2.The improvement of photocatalytic activity was primarily attributed to enhanced charge separation efficiency,which originated from the perfect 2D‐2D nanointerfaces and intimate interfacial contacts between TiO2 nanosheets and layered WS2.Based on experimental results,a double‐transfer photocatalytic mechanism for the TNS/WS2 heterojunctions was proposed and discussed.This work provides new insights for synthesizing highly efficient and environmentally stable photocatalysts by engineering the surface heterojunctions.
Yongchuan WuZhongmin liuYaru LiJitao ChenXixi ZhuPing Na
of main observation and conclusion The AL-P25 composites(AL=alizarin,P25=nano titanium dioxide)with oxygen vacancies were synthesized by a simple hydrothermal method and applied for the photoreduction of Cr(VI)under visible light.The AL-P25 composites were characterized by scanning electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy analysis,Fourier transform infrared spectrometer,thermo-gravimetric analysis,UV-vis diffuse reflectance spectroscopy,photoluminescence spectroscopy and electron paramagnetic resonance spectroscopy.The results suggested that the AL-P25 composites were successfully prepared,and alizarin was linked to P25 via Ti—O—C bonds.AL-P25 composites represented excellent photoreduction efficiency on Cr(VI)under visible light,which was 99.4%after 60 min of illumination.Finally,a photocatalytic mechanism of AL-P25 composites was proposed that ligand-metal charge transfer(LMCT)process between alizarin and P25 effectively enhances separation efficiency of photogenerated electrons and holes.
Meichen LiYarn LiJingyu ZhaoMingcheng LiYongchuan WuPing Na
We reported a facile and green hydrothermal strategy to tailor the carbon dots layer(CDL)and oxygen vacancies(Vo)modified on Ti0_(2),by using ascorbic acid as CDL precursor and Vo regulator.The amorphous CDL was uniformly coated on the surface of the as prepared CDL@TiO_(2-x) composites by Ti-O-C bond.With the increase of carbon content,the amorphous CDL gradually became thicker,while the Vo concentration first increased and then decreased.1.5 CDL@TiO_(2-x) possessed the highest Vo concentration.With the decoration of CDL and Vo,the photoreduction properties of CDL@TiO_(2-x) composites were significantly improved.Under simulated solar light and visible light,the reaction rates of 1.5 CDL@TiO_(2-x) were 9.6 times and 216 times higher than that of pure Ti0_(2)/respectively.Interestingly,the results discovered that CDL and Vo influenced the properties of CDL@TiO_(2-x) composites in different ways.The primary function of CDL was to improve the utilization of solar light,and the enhancement of the charge transfer ability was decided by Vo and CDL together.Our work provides a new strategy for the modification of Ti0_(2) and sheds new light on the respective role of CDL and Vo when they coexist in the catalyst.
