Rutile titania(TiO2)was successfully prepared via hydrolysis of TiCl4 in the presence of AlCl3.The powders were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Tell...Rutile titania(TiO2)was successfully prepared via hydrolysis of TiCl4 in the presence of AlCl3.The powders were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Teller(BET)surface area analysis.In the present system,AlCl3 functions as a nucleating agent and induces the formation of rutile TiO2.The influences of HCl and isopropanol concentrations on the purity and morphology of the rutile TiO2 were investigated.The purity of the rutile TiO2 increased with increasing concentration of HCl.Evenly dispersed rutile TiO2 particles with a spherical morphology were obtained when the HCl and isopropanol concentrations were 0.5 and 1 mol·L-1,respectively.Furthermore,the prepared TiO2 powders were used in adsorption tests of the heavy metal pollutant Cr(Ⅵ).Rutile TiO2 sample S-9 demonstrated greater adsorption performance and a removal efficiency that was greater than 99.95%after60 min of adsorption when the Cr(Ⅵ)concentration was 200 mg·L-1.The maximum adsorption capacity on rutile TiO2 was 28.9 mg·g-1.This work provides an easy path to prepare a high-performance rutile TiO2 adsorbent with potential applications in water pollution treatment.展开更多
Nanocrystalline titania was prepared by the homogeneous-precipitation method at temperature lower than 120℃. The properties of powders were identified by XRD,TEM and diffuse reflection spectra.The results showed that...Nanocrystalline titania was prepared by the homogeneous-precipitation method at temperature lower than 120℃. The properties of powders were identified by XRD,TEM and diffuse reflection spectra.The results showed that rutile titania formed at 70℃without calcination in air.Nanometer rutile TiO_2 had good crystalline and small particle size.The formation mechanism of rutile was also discussed.The photocatalytic activity of the prepared particles was tested for the degradation of methyl orange.The photocatalytic activity of rutile TiO_2 was higher than those obtained from Degussa P-25 TiO_2.The reasons for high photocatalytic activity of futile were discussed.展开更多
Two pure hexagonal phases of titanium dioxide, anatase and rutile, were grown on c-cut Al2O3 substrates via pulsed-laser deposition by changing only the growth and annealing conditions, but without changing the substr...Two pure hexagonal phases of titanium dioxide, anatase and rutile, were grown on c-cut Al2O3 substrates via pulsed-laser deposition by changing only the growth and annealing conditions, but without changing the substrate, target, or working gas. Purity of each phase was confirmed by x-ray diffraction, the quality of each film was studied using atomic force microscopy and scanning electron microscopy, and the interface between each substrate and film was studied using x-ray photoelectron spectroscopy. A binding layer of Ti2O3 was found to explain anatase growth under the very large lattice mismatch conditions.展开更多
This paper describes a novel, facile chemical pathway for preparing synthetic rutile from ilmenite. The pathway consists of two primary units, i.e., selectively sulfating ilmenite, which was realized via roasting ilme...This paper describes a novel, facile chemical pathway for preparing synthetic rutile from ilmenite. The pathway consists of two primary units, i.e., selectively sulfating ilmenite, which was realized via roasting ilmenite with(NH_4)_2SO_4followed by selective thermal decomposition of the sulfated ilmenite, and targeted leaching of the impurities. The effects of the process parameters were systematically investigated. The results showed that the optimum sulfation conditions were a mass ratio of(NH_4)_2SO_4to ilmenite of 14, temperature of 360 °C, and time of 120 min with a sulfation ratio of ~ 95%. The optimum thermal decomposition conditions were480 °C in N_2 atmosphere, and nearly all Ti OSO_4 were decomposed with co-decomposition of Fe SO_4 of 23%. For acid leaching, the optimum conditions were 2.5 wt% HCl, 98 °C and 120 min. Under those conditions, 94.2% iron was removed with a Ti O_2 dissolution loss b 1%. For alkali leaching, 67% Si O_2 was removed in 5 wt% Na OH at102 °C for 1 h. A synthetic rutile with a Ti O_2 content N 92 wt% and total Mg O + Ca O b 1.5 wt% was obtained.Based on these results, a schematic flowsheet was proposed. Additionally, it was found that the decomposition of Fe SO_4 mixed with Ti OSO_4 under N_2was inhibited due to its oxidation to a higher thermal stability Fe_2(SO_4)_3by oxygen emitted from the decomposition of Ti OSO_4. At the same time, Ti OSO_4 decomposition was promoted due to the immediate in situ consumption of oxygen by Fe SO_4. The synergetic effect might be responsible for the enhanced selectivity of sulfated ilmenite thermal decomposition.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51734002 and51774027)。
文摘Rutile titania(TiO2)was successfully prepared via hydrolysis of TiCl4 in the presence of AlCl3.The powders were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Teller(BET)surface area analysis.In the present system,AlCl3 functions as a nucleating agent and induces the formation of rutile TiO2.The influences of HCl and isopropanol concentrations on the purity and morphology of the rutile TiO2 were investigated.The purity of the rutile TiO2 increased with increasing concentration of HCl.Evenly dispersed rutile TiO2 particles with a spherical morphology were obtained when the HCl and isopropanol concentrations were 0.5 and 1 mol·L-1,respectively.Furthermore,the prepared TiO2 powders were used in adsorption tests of the heavy metal pollutant Cr(Ⅵ).Rutile TiO2 sample S-9 demonstrated greater adsorption performance and a removal efficiency that was greater than 99.95%after60 min of adsorption when the Cr(Ⅵ)concentration was 200 mg·L-1.The maximum adsorption capacity on rutile TiO2 was 28.9 mg·g-1.This work provides an easy path to prepare a high-performance rutile TiO2 adsorbent with potential applications in water pollution treatment.
基金The present research was supported by the High Technology and Development Project of the China （Grant：2003AA302320）National Natural Science Foundation of China （Grant：50021009）Basic Research Foundation of Tsinghua University （JC200206）.
文摘Nanocrystalline titania was prepared by the homogeneous-precipitation method at temperature lower than 120℃. The properties of powders were identified by XRD,TEM and diffuse reflection spectra.The results showed that rutile titania formed at 70℃without calcination in air.Nanometer rutile TiO_2 had good crystalline and small particle size.The formation mechanism of rutile was also discussed.The photocatalytic activity of the prepared particles was tested for the degradation of methyl orange.The photocatalytic activity of rutile TiO_2 was higher than those obtained from Degussa P-25 TiO_2.The reasons for high photocatalytic activity of futile were discussed.
文摘Two pure hexagonal phases of titanium dioxide, anatase and rutile, were grown on c-cut Al2O3 substrates via pulsed-laser deposition by changing only the growth and annealing conditions, but without changing the substrate, target, or working gas. Purity of each phase was confirmed by x-ray diffraction, the quality of each film was studied using atomic force microscopy and scanning electron microscopy, and the interface between each substrate and film was studied using x-ray photoelectron spectroscopy. A binding layer of Ti2O3 was found to explain anatase growth under the very large lattice mismatch conditions.
基金Supported by the National Key Projects for Fundamental Research and Development of China(2016YFB0600904)
文摘This paper describes a novel, facile chemical pathway for preparing synthetic rutile from ilmenite. The pathway consists of two primary units, i.e., selectively sulfating ilmenite, which was realized via roasting ilmenite with(NH_4)_2SO_4followed by selective thermal decomposition of the sulfated ilmenite, and targeted leaching of the impurities. The effects of the process parameters were systematically investigated. The results showed that the optimum sulfation conditions were a mass ratio of(NH_4)_2SO_4to ilmenite of 14, temperature of 360 °C, and time of 120 min with a sulfation ratio of ~ 95%. The optimum thermal decomposition conditions were480 °C in N_2 atmosphere, and nearly all Ti OSO_4 were decomposed with co-decomposition of Fe SO_4 of 23%. For acid leaching, the optimum conditions were 2.5 wt% HCl, 98 °C and 120 min. Under those conditions, 94.2% iron was removed with a Ti O_2 dissolution loss b 1%. For alkali leaching, 67% Si O_2 was removed in 5 wt% Na OH at102 °C for 1 h. A synthetic rutile with a Ti O_2 content N 92 wt% and total Mg O + Ca O b 1.5 wt% was obtained.Based on these results, a schematic flowsheet was proposed. Additionally, it was found that the decomposition of Fe SO_4 mixed with Ti OSO_4 under N_2was inhibited due to its oxidation to a higher thermal stability Fe_2(SO_4)_3by oxygen emitted from the decomposition of Ti OSO_4. At the same time, Ti OSO_4 decomposition was promoted due to the immediate in situ consumption of oxygen by Fe SO_4. The synergetic effect might be responsible for the enhanced selectivity of sulfated ilmenite thermal decomposition.
