The effect of Lanthanum content,calcinating temperature and calcinating time on the photocatalytic activity of Lanthanum doping TiO 2 was investigated.The study showed that samples treated under higher temperature and...The effect of Lanthanum content,calcinating temperature and calcinating time on the photocatalytic activity of Lanthanum doping TiO 2 was investigated.The study showed that samples treated under higher temperature and longer calcinating time exhibited higher photocatalytic activity.The X ray diffraction pattern revealed that the lattice of those samples was highly expanded.It is suggested that the highly distorted crystal lattice may be involved in producing more ways by which the hole was captured.Thus,the photocatalytic activity of samples treated under higher temperature and longer time was promoted.展开更多
Cationic Gemini surfactants, alkanediyl-α ,ω- bis(dimethyl dodecylammonium bromide) have been synthesized by the following method: firstly dodecyl bromide was prepared by the reaction of dodecanol with bromic acid i...Cationic Gemini surfactants, alkanediyl-α ,ω- bis(dimethyl dodecylammonium bromide) have been synthesized by the following method: firstly dodecyl bromide was prepared by the reaction of dodecanol with bromic acid in the presence of strong sulfuric acid. Dodecylbromide was then reacted with N,N- tetramethyl ethane diamine(or N,N- tetramethyl hexana diamine) to prepare the title- compounds. Micellization of these Gemini surfactants was investigated using conductivity measurement. The results showed that the critical micelle concentration(cmc) of the Gemini surfactants has a much lower value compared with that of the corresponding " monomer" . For a series of the Geminis with the same length(s) in the spacer chain, the cmc decreased with increasing the carbon number (m) in the alkyl chain. The aggregation number(N) of the micelle also drastically decreased with m. For the same value of m, the cmc varied slightly with s, which indicated that the electrostatic interaction between the ionic- groups of the " monomer" has been naturally changed duo to a link between the two ionic- groups of the " monomer" through a spacer. However, N was strongly decreased with s,which may be a reason of steric inhibition coming from the ionic- groups due to a link of spacer. With increasing temperature, micellization of the Gemini surfactants was slightly enhanced.展开更多
The iron doping titanium dioxide was prepared by sol-gel,step precipitation,co-precipitation and immersion methods,respectively.The photocatalytic activities of these prepared samples were evaluated in X-3B dispersion...The iron doping titanium dioxide was prepared by sol-gel,step precipitation,co-precipitation and immersion methods,respectively.The photocatalytic activities of these prepared samples were evaluated in X-3B dispersion irradiated under UV.The experimental results showed that the immersion method,especially using the nano TiO2 as immersion matrix,greatly enhanced the photocatalytic activity.One fold enhancement in photocatalytic activity was observed in the case of the sample prepared by immersion doping method.This may be attributed to the nano-size effect,the irreversible hole trapper in non-saturated bonding field of Fe3＋ and larger lattice strain.展开更多
In the water-in-oil mieroemulsion system of Triton X-100, 1-hexanol, cyclohexane and Fe（NO3）3 aqueous solution, α－Fe2O3 ultrafine particles were prepared by the method of precipitation using NH3. From transndssion...In the water-in-oil mieroemulsion system of Triton X-100, 1-hexanol, cyclohexane and Fe（NO3）3 aqueous solution, α－Fe2O3 ultrafine particles were prepared by the method of precipitation using NH3. From transndssion electron ndcrographs the mean dianreter of particles is about 3nm. The trifornlity of particle is good. These result have been confirmed by the method of Mossbauer spectrum measurement. The conditions of preparation of α－Fe2O3 ultrallne particles could be controlled easily and the reaction medium could be used cyclically.展开更多
文摘The effect of Lanthanum content,calcinating temperature and calcinating time on the photocatalytic activity of Lanthanum doping TiO 2 was investigated.The study showed that samples treated under higher temperature and longer calcinating time exhibited higher photocatalytic activity.The X ray diffraction pattern revealed that the lattice of those samples was highly expanded.It is suggested that the highly distorted crystal lattice may be involved in producing more ways by which the hole was captured.Thus,the photocatalytic activity of samples treated under higher temperature and longer time was promoted.
文摘Cationic Gemini surfactants, alkanediyl-α ,ω- bis(dimethyl dodecylammonium bromide) have been synthesized by the following method: firstly dodecyl bromide was prepared by the reaction of dodecanol with bromic acid in the presence of strong sulfuric acid. Dodecylbromide was then reacted with N,N- tetramethyl ethane diamine(or N,N- tetramethyl hexana diamine) to prepare the title- compounds. Micellization of these Gemini surfactants was investigated using conductivity measurement. The results showed that the critical micelle concentration(cmc) of the Gemini surfactants has a much lower value compared with that of the corresponding " monomer" . For a series of the Geminis with the same length(s) in the spacer chain, the cmc decreased with increasing the carbon number (m) in the alkyl chain. The aggregation number(N) of the micelle also drastically decreased with m. For the same value of m, the cmc varied slightly with s, which indicated that the electrostatic interaction between the ionic- groups of the " monomer" has been naturally changed duo to a link between the two ionic- groups of the " monomer" through a spacer. However, N was strongly decreased with s,which may be a reason of steric inhibition coming from the ionic- groups due to a link of spacer. With increasing temperature, micellization of the Gemini surfactants was slightly enhanced.
文摘The iron doping titanium dioxide was prepared by sol-gel,step precipitation,co-precipitation and immersion methods,respectively.The photocatalytic activities of these prepared samples were evaluated in X-3B dispersion irradiated under UV.The experimental results showed that the immersion method,especially using the nano TiO2 as immersion matrix,greatly enhanced the photocatalytic activity.One fold enhancement in photocatalytic activity was observed in the case of the sample prepared by immersion doping method.This may be attributed to the nano-size effect,the irreversible hole trapper in non-saturated bonding field of Fe3＋ and larger lattice strain.
文摘In the water-in-oil mieroemulsion system of Triton X-100, 1-hexanol, cyclohexane and Fe（NO3）3 aqueous solution, α－Fe2O3 ultrafine particles were prepared by the method of precipitation using NH3. From transndssion electron ndcrographs the mean dianreter of particles is about 3nm. The trifornlity of particle is good. These result have been confirmed by the method of Mossbauer spectrum measurement. The conditions of preparation of α－Fe2O3 ultrallne particles could be controlled easily and the reaction medium could be used cyclically.
