Surface Acidity of Aluminum Phosphate and Its Catalytic Performance in Benzene Alkylation with Long Chain Olefin

The acidic properties of aluminum phosphate （A1PO4-5） solid acid catalyst were characterized by tem- perature programmed desorption （TPD） of ammonia （NH3）, n-propylamine （n-C3HTNH2）, iso-propylamine [（CH3）2CHNH2] and n-dipropylamine [（C3H7）2NH] separately, and its catalytic performance in benzene alkylation with long chain olefin was studied in a fixed-bed reactor. The characterized acid amount of catalyst increased with the basicity of adsorbates. With increase of the activation temperature of catalyst, the acid amount characterized by NHa-TPD decreased, however, it increased when characterized by TPD using three other adsorbates. The desorption kinetics of TPD process and the deactivation kinetics of catalyst were investigated. The acidity and catalytic per- formance of catalyst was also correlated. The results showed that the acid amount and strength are well correlated with the activity and stability using NH3 as adsorbate, respectively, which indicated NH3 was a better basic adsorbate. It was also found that the catalyst with higher acid amount and lower acid strength on the surface exhibited the better catalytic performance and stability.

Preparation and modification of activated carbon for benzene adsorption by steam activation in the presence of KOH

A series of activated carbons from Taixi anthracite were prepared by steam activation in the presence of KOH and then they were modified by different methods. The regulation of porosity and the modification of surface chemistry were carried out with the aim to improve the benzene adsorption capacity of activated carbon. The influences of KOH and activation process parameters including activation temperature, activation time and steam flow rate on porosity of activated carbon were evaluated, and the effect of modification methods on surface chemistry was investigated. Also, the relationship between benzene adsorption capacity and porosity and surface chemistry was analyzed. Results show that activation temperature is the dominant factor in the activation process; the introduction of KOH into the raw material can enhance the reactivity of char in activation process, meanwhile it shows a negative effect on the porosity development, especially on the mesopore development. Results of FTIR analysis indicate that anthracite-based activated carbon with condensed aromatics and chemically inert oxygen does not present the nature to be surface modified. Besides, benzene adsorption capacity has an approximate linear relationship with surface area and in our preparation, benzene adsorption capacity and surface area of activated carbon are up to 1210 m 2 /g and 423 mg/g, respectively.

In Vitro Antifungal Activity of the Extract and Compound from Acorus tatarinowii Against Seven Plant Pathogenic Fungi

Acorus tatarinowii Schott is a traditional Chinese medicine plant and has multiple bioactivities in medicine and pesticide field. In this study, the antifungal compound 1,2-dimethoxy-4（2-propenyl） benzene was isolated from A. tatarinowii Schott by activity-directed isolation method, and the inhibitory activity of the extract and 1,2-dimethoxy-4（2-propenyl） benzene against seven plant pathogenic fungi was evaluated. The results showed that the extract and 1,2-dimethoxy-4（2- propenyl） benzene had high inhibitory activity against hyphal growth of Thielaviopsis paradoxa （de Seynes） V. Hohnel, Pestalotia mangiferae P. Henn., Fusarium oxysporum f. sp. niveum （E. F. Smith） Syn. et Hans., Alternaria alternate Tanaka, Colletotrichum musae （Berk et Curt） V. Arx, Sphaceloma fawcettii Jenk., and Mycosphaerella sentina （Fr.） Schroter. The EC50 values of extract were 1.6162, 1.6811, 1.1253, 3.5771, 1.7024, 2.2284, and 2.2221 g L^-1, respectively, and the EC50 values of 1,2-dimethoxy-4（2-propenyl） benzene were 0.1021, 0.0997, 0.0805, 0.1742, 0.1503, 0.1853, and 0.1924 g L^-1, respectively. 1,2-Dimethoxy-4（2-propenyl） benzene also inhibited spores germination of T. paradoxa （de Seynes） V. Hohnel and F. oxysporum f. sp. niveum （E. F. Smith） Syn. et Hans., with the inhibitory rates of 98.81 and 100% at a concentration of 0.4 g L^-1 after 8 h, respectively. 1,2-Dimethoxy-4（2-propenyl） benzene is a potential botanical antifungal agent for controling of plant fungal diseases.

Study on Coconut Shell Activated Carbon Temperature Swing Adsorption of Benzene and Formaldehyde

Adsorption can be used to recover effectively the volatile organic gases(VOCs)in the exhaust gas from factories through using an appropriate adsorption bed.Due to form a physical or chemical bond,adsorption occurs between the porous solid medium and the liquid or gas multi component fluid mixture.The regeneration capa-city of the adsorbent is as important as the adsorption capacity and it determines the economics of the adsorption system.The regeneration of adsorbent can be realized through changing the pressure or temperature of the system.Here,activated carbon samples from coconut shell were prepared and characterized.Benzene or formal-dehyde in the mixed air was used as the adsorption object,and the adsorption experiment was carried out in a U-shaped bed.Discussed how adsorption was affected by activated carbon type,adsorbate and temperature.The results show that oxidation modifed activated carbon can increase the adsorption effect of form aldehyde,but will reduce the ad sorption effect of benzene,because their ad sorption mechanism is different.At 30℃,the saturated adsorption apacity of AC-0 for benzene is 437.0 mg/g.and that of AC-1 for formaldehyde is 670.5 mg/g.In the experimental range,it is found that the adsorption capacity increases with the decrease of temperature,and their changes are very consistent with the ftted ExpDecay1 function.

Gas Phase Activation of Methane Molecule with Lead Benzene Dication Complex Ion, [Pb(Benzene)₂]²⁺

Motivated by the search for ways of a more efficient usage of the ubiquitous, and unexploited resources of methane, recent progress in the gas-phase activation of methane by metal dication complex ion is discussed. The gas phase theoretical and experimental analysis on [Pb(Benzene)2]2+ was conducted. The [Pb(Benzene)2]2+ complex ions were prepared using a combination of the pick-up technique and high energy electron impact, and then held in a cold ion trap. Excitation with tuneable UV radiation resulted in the formation of [Pb(Benzene)2(H2O)]2+, [Pb(Benzene)2(H2O)2]2+, [Pb(Benzene)]+, Pb+ and Benzene+ ions when the experimental results were analysed. The two optimised geometries of [Pb(Benzene)2]2+ namely the C2V eclipse and C2 staggered were observed. Methane activation of [Pb(Benzene)2]2+ complex ion yielded [Pb(Benzene)2(Me)]2+. [Pb(Benzene)2(H2O)(Me)2]2+,? [Pb(Benzene)2(H2O)(Me)]2+, [PbBenzene(Me)3]2+ and [Pb(Benzene)(Me)]2+. The PEC calculated binding energy of methane to lead benzene dication complex ion was approximately 25.45% higher than the value recorded on DFT calculation. This difference was due to the charge differences on the lead metal centre. While the actual calculated charge on the Pb metal in the optimised geometry was 1.68 the charge of +2 on the Pb metal was considered in the PEC calculation.

Adsorption Breakthrough of Benzene in the Fixed Bed of Modified Activated Carbon under Different Humidity Conditions

The breakthrough curves of benzene and water on modified activated carbons（ACs） were investigated.Temperature-programmed desorption（TPD） experiments were conducted to measure the TPD curves of benzene and water on modified and unmodified ACs and to estimate the activation energy for the desorption of benzene on the modified ACs.Starting with unmodified ACs,two modified ACs were prepared by using two different types of silane,designated by KH560 and 1706.The results showed that the activation energy for the desorption of benzene on KH560/AC and 1706/AC was higher than that on unmodified AC.In addition,the activation energy for the desorption of water on KH560/AC and 1706/AC was lower than that on unmodified AC.The breakthrough curves of benzene obtained from the experimental observations under different humidity conditions were compared with the results of the TPD experiments.The results show that the modified ACs are less affected by water,whereas the unmodified ACs are more affected by water,indicating that surface modification by organosilane compounds can improve the adsorption of benzene on the activated carbo,which weakens the adsorption of water.

Toxicity Measurement of Halogeno-benzene against Vibrio Qinghaiensis (Q67) and Their 2D,3D-QSAR Study

Toxicities （–lgEC50） of 16 halogeno-benzenes against vibrio qinghaiensis （Q67） were measured systematically, and their 2D-QSAR model （R2=0.875, q2=0.821） was established, which included two parameters： averaged polarizability （α） and total energy （TE）. The proposed model indicated that the toxicities of this kind of compounds were proportionate to α, i.e., their toxicities were relative to the molecular volume. Furthermore, 3D-QSAR model （R2=0.929, q2=0.712） of –lgEC50 was proposed by using comparative molecular force field （CoMFA） based on the molecular simulation. To our interest, 3D-QSAR model suggested that the hydrophobicity of substituents was the dominating factor for the toxicities, the electrostatic effect was the secondly important, and the steric field gave the least contribution. Comparably, the prediction ability of the 3D-QSAR model is slightly more advantageous than that of 2D-QSAR, and they can be used complementally in the toxicity description of this kind of compounds.

Ionization and Dissociation of Benzene and Aniline under Deep Ultraviolet Laser Irradiation

We report a study on photo-ionization of benzene and aniline with incidental subsequent dissociation by the customized reflection time-of-flight mass spectrometer utilizing a deep ultraviolet 177.3 nm laser.Highly efficient ionization of benzene is observed with a weak C4H3+fragment formed by undergoing disproportional C-C bond dissociation.In comparison,a major C5H6+·fragment and a minor C6H6+·radical are produced in the ionization of aniline pertaining to the removal of CNH·and NH·radicals,respectively.First-principles calculation is employed to reveal the photo-dissociation pathways of these two molecules having a structural difference of just an amino group.It is demonstrated that hydrogen atom transfer plays an important role in the cleavage of C-C or C-N bonds in benzene and aniline ions.This study is helpful to understand the underlying mechanisms of chemical bond fracture of benzene ring and related aromatic molecules.

Surface Modification of Commercial Activated Carbon (CAG) for the Adsorption of Benzene and Toluene

In this work, we determined the surface characteristics of natural (CA-1) and HNO3 treated (CA-2) CAG. Equilibrium, kinetics and breakthrough for adsorption of benzene and toluene by CA-1 and CA-2 were studied. Concentrations of benzene and toluene (mg/L) were determined by gas chromatography with headspace extraction. The data of adsorption kinetic and equilibrium were best fitted by pseudo-second order model and Langmuir isotherm, respectively. The best results of benzene and toluene adsorption from fixed bed were obtained at volumetric flow rate (Q1 = 70 mL/min) using adsorbent CA-2. The study of inferential statistics revealed that CA-1 and CA-2 adsorbents are statistically different at a 5% significance level.

一种生物活性炭的制备及其对BTEX去除效果研究

针对BTEX污染问题,在传统活性炭吸附技术的基础上,设计了一种依托特殊微生物的,能够进行原位再生的生物活性炭并对其处理效率进行研究。从被苯系化合物污染的土壤样本中提取了微生物样品,经过筛选训化后保留了3株菌种B-01、B-02、B-03。利用生物滴滤法将微生物固定在椰壳活性碳上制成生物活性碳(BAC),通过人工模拟的BTEX废气研究BAC再生效应对于处理BTEX废气的作用。研究结果表明,3株菌种分别为芽孢杆菌(Bacillus)、芽孢杆菌(Bacillus)和假单胞菌(Pseudomonas),最适反应温度为30℃,通过持续喷淋营养液,活性碳上挂载的菌种能够在35 d内保持活性。所制备的BAC对乙苯的吸附能力最强,乙苯去除率可达98.75%。BAC在低负载情况下BTEX去除率最高可达98%。通过微生物挂膜延长了活性炭的使用寿命,为降低石油加工废气处理成本提供了技术支持,具有良好的实用价值。

基于分子模拟的甲醛和苯在活性炭上的竞争吸附特性研究

在不同实验条件下测得活性炭对室内污染物苯和甲醛的吸附穿透曲线,结果表明增加湿度会降低苯和甲醛的吸附量,由于两者极性不同,湿度对其影响程度不同。在实验基础上,利用Materials Studio分子模拟软件中的Visualizer模块构建不同孔径(1、2、4 nm)的活性炭狭缝模型,以巨正则蒙特卡洛方法模拟单一组分的苯和甲醛在不同温度(288.15、293.15、323.15 K)下的吸附情况以及苯、甲醛共存时的竞争吸附情况。通过实验吸附量与模拟吸附量对比验证模拟结果正确性。模拟结果显示,3种温度条件下,苯的吸附量变化较小,但是孔径对苯的吸附量影响较大,吸附量随着孔径的增大而增大。苯的吸附能大于甲醛,活性炭对苯的吸附能力大于甲醛。

改性活性炭对苯废气吸附性能的研究

对低浓度含苯废气的有效去除方法之一是活性炭吸附法。针对治理工业含苯废气 ,研制了高吸附量、低成本的活性炭。亦即 ,通过对普通煤质活性炭进行酸碱改性处理 ,除去酸碱可溶性物质 ,使活性炭的灰分大大降低 ,从而提高了活性炭的比表面积 ,同时 ,提高了活性炭的吸附活性。进而 ,通过研究不同的改性方法对活性炭的苯饱和吸附量、比表面积、孔径及灰分的影响 ,确定了最佳改性方法。研究结果表明 :采用酸、碱交替改性方法处理普通活性炭 ,是提高活性炭的苯吸附量。

沉淀法制备苯选择加氢制环己烯Ru-Zn催化剂的表征

沉淀法制备的Ru-Zn体系用于苯选择加氢制环己烯,苯转化40%时,环己烯选择性达85 5%。XRD研究证实了Zn和Ru以固溶体形式存在。用噻吩吸附发现,10-6数量级的硫对选择性产生明显影响。XRD半高宽法测得Ru微晶粒径3～5nm。Ru-Zn催化剂BET比表面积62 5m2/g,平均孔径16 05nm,具有两端开放的管状毛细孔结构,反应可利用的孔分布均匀。并与浸渍法制备的Ru-Zn/SiO2对比,探讨催化剂的活性相,活性中心性质,及比表面积、孔性质与活性选择性的关系。

氯苯类胁迫对蚕豆幼苗超氧化物歧化物活性的影响

采用室内培养方法,研究了土壤中不同浓度氯苯(CB)、1,2,4-三氯苯(TCB)和六氯苯(HCB)胁迫对蚕豆幼苗生长、超氧化物歧化酶(SOD,EC1.15.1.1)活性及丙二醛(MDA)含量变化的影响。结果表明,50～300μg·g-1TCB处理5d后蚕豆幼苗生长受到抑制(P<0.05和P<0.01)。50～300μg·g-1TCB胁迫1～5d对蚕豆幼苗SOD活性的影响表现出明显的剂量-效应关系。TCB处理5d后的幼苗恢复培养3d,50μg·g-1TCB处理组的SOD活性得到恢复,而100和300μg·g-1TCB处理组的SOD活性明显高于对照(P<0.05和P<0.01)。试验亦表明,100和300μg·g-1TCB处理3d和5d,幼苗MDA含量均比对照显著增加(P<0.05和P<0.01),并且与TCB浓度之间存在明显的正相关关系。上述结果表明,蚕豆幼苗SOD活性及MDA含量可作为短期土壤TCB污染的生物标记物,而50～1000μg·g-1CB或HCB处理5d对蚕豆幼苗没有产生明显的毒性效应。

活性炭纤维吸附苯系物影响因素的研究

研究了吸附法去除室内苯系物。实验用活性炭纤维(ACF)作为苯系物的吸附剂,苯、甲苯作为苯系物的代表物。研究苯系物的浓度、气流量及填充密度等条件对活性炭纤维吸附性能的影响。实验结果表明:初始浓度大的苯系物穿透时间短;当两组分气体(苯、甲苯)混合吸附时,吸附能力强的甲苯有置换吸附能力弱的苯的现象发生;气流量加大会较快到达穿透点和吸附饱和点,使穿透曲线发生左移,曲线斜率不变;填充密度对穿透时间与饱和时间都有影响,密度大有利于吸附。

Pd/Fe双金属对水中m-二氯苯的催化脱氯

Pd/Fe bimetallic catalysts were synthesized via chemical deposition and used to treat m-DCB.Batch experiments demonstrated that the Pd/Fe bimetallic particles could effectively dechlorinate m-DCB.The dechlorination efficiency reached 90% at a Pd/Fe loading ratio of 0.02% (mass) and metal to solution ratio 4g∶75ml in 90 min.Dechlorination was affected by several factors such as reaction temperature, pH, Pd/Fe ratio, and the induction of Pd/Fe catalysts.Chlorobenzene represents the partially stable dechlorinated intermediate in the generation of the final product (i.e., benzene), while part of m-DCB was dechlorinated to benzene directly.The dechlorination reaction was believed to take place mainly on the active surface sites of the Pd/Fe bimetallic particles via a pseudo-first order reaction, and the activation energy of this reaction was found to be 96.6 kJ·mol -1 .

改性活性炭对苯的吸附性能

本文研究了用H_3PO_4,SN (以 NaNO_2为主的复盐) 等改性的活性炭对苯的吸附性能,在不同苯浓度和空述下,经适当改性的活性炭对苯的吸附容量大于活性炭本身,探讨了改性活性炭的表观比表面与其吸附性能的关系。

TiO_2/AC复合光催化剂对苯和丁醛的气相光催化降解机理

利用溶胶-凝胶并水热处理法制备了TiO2光催化剂和TiO2/AC复合光催化剂,在静态光催化反应器中研究了苯和丁醛的气相吸附和光催化降解,利气相色谱分析确定了生成的中间体.结果表明,TiO2/AC复合光催化剂比TiO2光催化剂具有较强的吸附能力和较高的光催化活性;在TiO2和TiO2/AC上,苯(或丁醛)光催化降解产生相同的中间体,表明在两种催化剂上发生的光催化反应遵循相同的机理,进而讨论了其可能的光催化氧化途径.

苯在改性活性炭上的脱附活化能

采用浸渍法制备了KH560/改性活性炭、1706/改性活性炭和A172/改性活性炭等3种活性炭,并利用程序升温脱附技术测定了苯在这3种改性活性炭上的脱附活化能.结果表明,苯在经改性的活性炭上的脱附活化能均大于其在未改性活性炭上的脱附活化能,表明用有机硅烷改性活性炭可以提高其对苯的吸附能力.IGC分析结果表明,经硅烷改性的活性炭的特殊作用吸附自由能-Gs均小于原始活性炭的-Gs,这4种活性炭表面与苯的特殊作用吸附自由能-Gs大小顺序与苯在这些活性炭上的脱附活化能大小顺序正好相反,这表明-Gs越小,吸附质与活性炭表面形成的吸附越牢固,吸附质从其表面脱附所需的活化能越大.

活性炭对苯及甲苯蒸汽吸附能力相关性的研究

以4种性质不同的粉状活性炭为对象，研究了它们对苯及甲苯蒸汽吸附能力。得知：活性炭对苯及甲苯蒸汽的吸附能力具有较好的相关性，可以用甲苯代替苯作吸附质来评价活性炭对有机溶剂蒸汽的吸附能力，并发现两者的相关性程度与活性炭的平均孔隙半径大小有密切关系。