天然管状矿物埃洛石负载TiO_2的微结构及对亚甲基蓝的光催化降解研究

埃洛石是一种天然的管状粘土矿物,在环境治理方面有广泛的应用。室温条件下通过钛酸丁脂的水解反应在埃洛石上负载了TiO_2。分别在避光条件和紫外光照射下,通过亚甲基蓝溶液的降解研究了埃洛石和负载TiO_2埃洛石的吸附和光催化性能。通过亚甲基蓝被吸附和降解的量,评价了样品的吸附和光催化性能。由于复合了吸附和光催化性能,负载TiO_2埃洛石能迅速降解水中的有机污染物——亚甲基蓝,其降解速度要快于纯埃洛石,因为纯埃洛石只有吸附性能。这是埃洛石应用研究方面的一次新尝试。该研究对大气和水体中各种污染物的去除和降解必然有积极的指…     

静电自组装制备斜发沸石负载纳米TiO2吸附及光催化降解甲基橙染料研究

为了实现纳米TiO2的固定化负载,提高材料对污染物的光催化效率,采用静电自组装方法制备了天然斜发沸石负载纳米TiO2光催化材料。采用硅烷偶联剂(OCH3)3Si(CH2)3SH干法改性斜发沸石,采用30%H2O2/HOAc氧化剂将偶联剂巯基基团(—SH)氧化为易电离的磺酸基基团(—SO3H),带负电荷的沸石与钛聚合阳离子在静电引力的作用下自发地组装在一起,经一定温度的焙烧得到斜发沸石负载纳米TiO2光催化材料。采用XRD和SEM对材料进行分析和表征,采用甲基橙染料评价材料的吸附和光催化性能,结果表明:沸石负载纳米TiO2对甲基橙染料具有吸附与光催化的协同作用,静电自组装方法制备的材料的光催化性能较传统方法有所提高。     

钛柱撑膨润土光催化剂的制备及其催化性能的研究

运用紫外光光助的方法成功制备了钛柱撑膨润土光催化剂,该方法使膨润土层间钛柱TiO_2晶相能在150℃的低温烧结下由无定型转变为高催化活性的锐钛矿。由于钛柱的形成,柱撑后的膨润土的层间距达到1.94nm,明显大于原土的1.56nm。实验以罗丹明B为考察对象,研究了钛柱撑膨润土光催化剂的吸附能力,以及它在紫外光照射下的光催化性能和降解反应的动力学方程。实验表明:钛柱撑膨润土光催化剂能强烈地吸附罗丹明B并且能迅速地将它降解,其降解反应的动力学方程符合1.5级。钛柱撑膨润土光催化剂的制备及其催化性能的研究@唐剑文$华南理工大学环境科学…     

天然沸石对提高TiO2光催化活性的作用

以天然沸石为载体,研究了其负载TiO2后对甲基橙溶液的光催化降解效果,探讨了TiO2与沸石的结合类型。通过对负载前后反应动力学模式变化的研究,阐释TiO₂/沸石体系的光催化反应进程。从复合前后样品的AFM、IR、发射光谱变化上看,部分TiO₂与沸石载体形成了新的Ti－O－Si或Ti－O－Al的化学键。光催化实验结果和动力学分析显示,在反应的初始阶段,当TiO₂中引入多孔的沸石载体后,催化剂对甲基橙的降解过程由原来纯粹的吸附控制模式向反应控制模式转变,但还没有达到纯粹的反应控制的程度。沸石载体是通过提高吸附过程的速率,来提升初始阶段的光催化反应速率（R₀）的。     

利用氨吸附漫反射红外光谱法探测蒙脱石的固体酸性

用氨吸附漫反射红外光谱学方法,借助图谱拟合解谱手段,探测了不同预处理温度下蒙脱石表面酸性变化特征,并分析了其变化原因。结果表明,低温热处理后的蒙脱石,其B酸和L酸量增大;经较高温度(400、600℃)煅烧的样品,层间距急剧减小,氨分子难以进入层间与酸位发生反应,可探测到的两种酸量都将减少。     

制备多孔镍负载TiO2薄膜光催化降解喹啉和化工废水

为了获得具有高光催化活性和稳定性的TiO2薄膜,采用浸渍涂布法不加黏结剂将Deguessa P-25TiO2固定在泡沫镍基片上,制备成泡沫镍基负载TiO2薄膜,并以Ti-10薄膜为光催化组件制备了一种新型连续流内循环光催化反应器。表征结果显示:P-25薄膜呈混晶相,增大负载浓度会增加基片上结晶质(如锐钛矿相(101))数量、团聚颗粒数量、表面微裂痕以及比表面积;高温煅烧下泡沫镍基片上Ni元素以金属Ni和NiO形式扩散到薄膜表面,形成NiO-Ni体系,有助于提高薄膜的光催化活性;当负载P-25质量分数为10%时,薄膜表层Ni原子比为12.29%,此时薄膜具有最佳光催化活性。以Ti-10样品为光催化薄膜组件制备了一种连续流光催化反应装置,该装置降解化工废水的实验结果显示反应装置连续运行一周,出水可达到一级排放标准。     

共沉淀法制备含Zn水滑石及光催化性能

以共沉淀法制备Zn~(2+)和M~(3+)(M为Al、Cr、Fe)摩尔比为3:1,CO_3~(2-)为层间阴离子的含Zn水滑石(Zn_3M-CO_3-LDHs)。分别采用粉末X射线衍射(XRD)、红外光谱(FT-IR)、紫外-可见漫反射光谱(UV-Vis DRS)和热重-差热分析(TG-DTA)等技术对3种含Zn水滑石的结构和性质进行表征。结果表明合成的3种含Zn水滑石都具有碳酸根柱撑水滑石的典型层状结构,且结构规整、晶相单一。Zn_3Cr-CO_3-LDHs在可见光区域的吸收范围最宽。热稳定性顺序为Zn_3Cr-CO_3-LDHsZn_3Al-CO_3-LDHsZn_3Fe-CO_3-LDHs。测试了3种含Zn水滑石的光催化降解罗丹明B溶液性能,结果表明:3种含Zn水滑石均能有效光催化降解罗丹明B,Zn_3Cr-CO_3-LDHs光催化罗丹明B 70 min的降解率达到95.8%,光催化效果最好;Zn_3Al-CO_3-LDHs和Zn_3Fe-CO_3-LDHs的光催化降解率超过84%,光催化效果相近。动力学研究表明3种含Zn水滑石光催化降解罗丹明B过程符合一级反应动力学模型,反应速率常数大小顺序为:Zn_3Cr-CO_3-LDHsZn_3Al-CO_3-LDHsZn_3Fe-CO_3-LDHs。     

BiOBr/铁改性蒙脱石对罗丹明B的光催化降解性能研究

在低温条件下通过铁改性蒙脱石与BiOBr复合成功合成了一种新型的光催化材料,称为BiOBr/Fe-Mt。运用X射线粉末衍射(XRD)、透射电镜(TEM)、傅立叶转换红外光谱(FTIR)、紫外可见漫反射光谱(UV-Vis DRS)对BiOBr/Fe-Mt材料进行表征。同时以λ400 nm的可见光为光源,开展该催化剂对罗丹明B(Rh B)的光催化降解实验以评估其光催化活性。结果表明,支撑材料投加量被固定在2.5 g的条件下,采用铁改性蒙脱石制备的BiOBr/Fe-Mt材料对Rh B的光催化降解活性高于采用钠基蒙脱石制备的BiOBr/Na-Mt。光催化活性的显著提高,主要归因于:1 BiOBr/Fe-Mt的禁带宽度降低至2.46 e V,或可能形成了BiOBr/铁氧化物异质结结构;2 BiOBr/Fe-Mt上仅发生较少的十六烷基三甲基溴化铵有机分子残留。这些结构因素均可以有效促进BiOBr/Fe-Mt上Rh B的光催化降解。     

膨胀石墨负载纳米TiO_2材料对机油的吸附和光催化降解

用溶胶凝胶法将纳米锐钛矿负载到膨胀石墨上,制备了即可吸油,又可降解油的膨胀石墨-TiO_2复合材料(EG-TiO_2)。在制备EG-TiO_2的工艺条件中,浸渍次数是影响其吸油能力的最主要因素,浸渍次数增多饱和吸油量下降。用失重法和红外光谱法研究EG-TiO_2催化降解机油的结果表明,EG-TiO_2对机油有明显的光催化降解效果,性能优于纯纳米TiO_2粉,其原因与EG-TiO_2中的纳米TiO_2具有三维立体薄片状结构及具有较高吸油性能有关。膨胀石墨负载纳米TiO_2材料对机油的吸附和光催化降解@曹宏$武汉工程大学材料学院!430074 @马恩宝$武汉工程大…     

活性炭颗粒负载TiO2的光催化性能研究

文章研究了溶胶-凝胶法制备活性炭颗粒负载TiO2的光催化作用.以20W紫外灯作光源,酸性大红染料为目标物,探讨光催化剂的最佳制备条件.实验结果表明,当钛酸四丁脂与无水乙醇按1:8比例制备Ti02溶胶,活性炭颗粒浸涂凝胶一次,在450℃煅烧2h,酸性大红染料的降解率可达78%.当溶胶掺杂Fe(3 )时,可增强光催化效果,实验表明120min对酸性大红染料废水的光催化降解率由78%提高到97%.     

Primary cracking of kerogens. Experimenting and modelling C1, C2–C5, C6–C15 and C15+ classes of hydrocarbons formed

Mathematical models of hydrocarbon formation can be used to simulate the natural evolution of different types of organic matter and to make an overall calculation of the amounts of oil and/or gas produced during this evolution. However, such models do not provide any information on the composition of the hydrocarbons formed or on how they evolve during catagenesis.From the kinetic standpoint, the composition of the hydrocarbons formed can be considered to result from the effect of “primary cracking” reactions having a direct effect on kerogen during its evolution as well as from the effect of “secondary cracking” acting on the hydrocarbons formed.This report gives experimental results concerning the “primary cracking” of Types II and III kerogens and their modelling. For this, the hydrocarbons produced have been grouped into four classes (C₁, C₂–C₅, C₆–C₁₅ and C₁₅₊). Experimental data corresponding to these different classes were obtained by the pyrolysis of kerogens with temperature programming of 4°C/min with continuous analysis, during heating, of the amount of hydrocarbons corresponding to each of these classes.The kinetic parameters of the model were optimized on the basis of the results obtained. This model represents the first step in the creation of a more sophisticated mathematical model to be capable of simulating the formation of different hydrocarbon classes during the thermal history of sediments. The second step being the adjustment of the kinetic parameters of “secondary cracking”.     

地下水中高锰酸盐指数和硝酸根铵根稳定性研究

高锰酸盐指数(CODMn)、硝酸根(NO-3)、铵根(NH+4)是判断水体是否受到三氮污染的重要指标。对于测定这三个指标的水样保存方式和时间,地质行业标准和国内外主要国家标准间存在明显差异。地质行业标准规定地下水样品原水室温保存,CODMn和NH+4在3天内测定;NO-3在20天内测定;国家标准和美国标准推荐样品硫酸酸化,避光或冷藏保存,在2~7天内完成CODMn和NO-3和1~7天内完成NH+4测试。为了分析各类标准在样品保存要求上的差异对检测结果的影响,确保检测数据能真实地反映水体污染状况,找寻简便的保存方式,本文在广州地区采集地下水,按照地质行业标准与国家标准进行处理和保存,并在不同时间段对三个指标进行测试。分析验证结果表明:地质行业标准与国家和美国标准关于水样的保存方法均非常可靠。地质行业标准主要针对静态地下水,保存方法相对宽松;国家标准和美国标准适用范围除了地下水,还包括动态的地表水和废水,采样对象成分更为复杂,更不稳定,更容易受外界影响发生变化,故保存条件高于地质标准。在广州地区,采用原水室温避光保存水样,CODMn、NH+4保存时间可为5天,NO-3保存时间可为30天;采用酸化水室温保存水样,CODMn、NO-3和NH+4保存时间可长达30天。这两种方式均比地质行业标准和国家标准推荐的有效时间长,且原水和酸化水室温保存方式相对于冷藏保存方式更为方便。本文提出,如果采集的水样能方便、快速送达实验室,可采用原水保存;如果不能在短时间内送达实验室检测,可采用硫酸酸化保存。     

K-Ar和40Ar/39Ar定年数据质量评价与Q值提出

K-Ar和K-Ar/39Ar的定年测试质量的评价是正确运用测试结果的前提.过去的研究,多通过仪器测试的偏差和误差传递来评价测试结果可靠性和精度.MSWD和Probability的提出,给出测试的内外误差概念,因考虑了仪器和样品二者的匹配性而得到广泛应用.这也说明,影响K-Ar和40Ar/39 Ar的定年测试结果的因素可以是来自仪器设备,也可以来自样品自身的特性.本文由K-Ar和40 Ar/39 Ar的定年技术的原理、流程为出发点,通过对各个测试项的误差传递和对结果精度影响的数学方法评估,提出了影响测试精度的Q1和Q2参数,分别代表与样品有关的属性.Q1是样品钾含量、囚禁36 Ar的含量、以及样品40Ar/36Ar的初始比值的综合参数,是决定仪器测试中误差传递系数大小的重要影响因子.Q2是样品钾含量、囚禁36 Ar的含量、以及样品40 Ar/36 Ar的初始比值误差的综合参数,用来评价样品等时线年龄精度.在地质意义上,Q2是评价样品是否满足“同源、同时、封闭”特性的重要量化指标.根据这两个参数,可以判别测试数据质量优劣是源于测试仪器,还是样品属性.由Q1和Q2的分析可知,任何一项K-Ar和40Ar/39 Ar的定年测试都应该充分考虑仪器性能和样品属性,设计合理的测试流程是K-Ar和40 Ar/39 Ar的定年获得较高质量数据的关键.     

Al_2O_3/Ti:风化与蚀变过程中的原岩示踪

Al_2O_3和Ti在风化和热液蚀变等地球化学过程中通常被认为是不活动元素,两者的比值Al_2O_3/Ti常被用来指示地球化学作用过程。通过对中国157件火成岩样品元素含量平均值的统计发现,火成岩样品中Al_2O_3/Ti与SiO_2含量值之间存在着较好的幂函数关系:ln(Al_2O_3/Ti)=0.073×SiO_2-0.89,式中Al_2O_3和SiO_2和Ti含量单位均为%。本文基于得到的经验方程和TAS图解构建了一个新的判别岩石类型的图解——Al_2O_3-Ti图解。该图解可以区分酸性岩、中酸性岩、中性岩、中基性岩-基性岩四类岩性。通过对三个火成岩风化剖面的研究发现,花岗岩风化剖面从新鲜基岩到风化形成的土壤在Al_2O_3-Ti图解中均落在酸性岩区,花岗闪长岩风化剖面从新鲜基岩到风化形成的土壤样品均落在中酸性岩区,玄武质安山岩风化剖面从新鲜基岩到风化形成的土壤样品均落在中基性岩-基性岩区。不同风化程度的风化产物与其母岩在Al_2O_3-Ti图解中所在的区域一致,即Al_2O_3-Ti图解可以用来追溯火成岩风化产物的母岩岩性。通过对胶东焦家金矿和豫西牛头沟金矿两个矿区岩石的研究发现,黑云母花岗岩从新鲜岩石到其蚀变岩及其形成矿石的样品在Al_2O_3-Ti图解中均落在酸性岩区。玄武质安山岩从新鲜岩石到其蚀变岩及其形成矿石的样品在Al_2O_3-Ti图解中均落在中基性岩-基性岩区。即不同蚀变程度的蚀变产物与其原岩在Al_2O_3-Ti图解中所在的区域一致,这表明新构建的Al_2O_3-Ti图解可以用来示踪蚀变岩的原岩性质。     

Crustal thickness and VP/VS variations in the Grenville orogen (Ontario, Canada) from analysis of teleseismic receiver functions

We have developed a simple semblance-weighted stacking technique to estimate crustal thickness and average V_P/V_S ratio using teleseismic receiver functions. We have applied our method to data from 32 broadband seismograph stations that cover a 700 × 400 km² region of the Grenville orogen, a 1.2–0.98 Ga Himalayan-scale collisional belt in eastern North America. Our seismograph network partly overlaps with Lithoprobe and other crustal refraction surveys. In 8 out of 9 cases where a crustal-refraction profile passes within 30 km of a seismograph station, the two independent crustal thickness estimates agree to within 7%. Our regional crustal-thickness model, constructed using both teleseismic and refraction observations, ranges between 34.0 and 52.4 km. Crustal-thickness trends show a strong correlation with geological belts, but do not correlate with surface topography and are far in excess of relief required to maintain local isostatic equilibrium. The thickest crust (52.4 ± 1.7 km) was found at a station located within the 1.1 Ga mid-continent (failed) rift. The Central Gneiss Belt, which contains rocks exhumed from deep levels of the crust, is characterized by V_P/V_S ranging from 1.78 to 1.85. In other parts of the Grenville orogen, V_P/V_S is found to be generally less than 1.80. The thinnest crust (34.5–37.0 km) occurs northeast of the 0.7 Ga Ottawa–Bonnechere graben and correlates with areas of high intraplate seismicity.     

低硅埃达克岩和高硅埃达克岩问题

低硅埃达克岩(low-SiO2adakites,LSA,SiO2<60%)和高硅埃达克岩(high-SiO2adakites,HSA,SiO2>60%)的术语是Martin等(2005)提出来的。本文不赞同上述分类,因为,他们的低硅埃达克岩是赞岐岩而不是埃达克岩。赞岐岩是幔源的,埃达克岩是壳源的,虽然埃达克岩可以与地幔混合形成高镁的埃达克岩,但仍然是壳源的。不应当把壳源的岩浆和幔源的岩浆混淆起来。     

The rise of trees and their effects on Paleozoic atmospheric CO2 and O2

The rise of large vascular plants during the mid-Paleozoic brought about a major increase in the rates of weathering of silicate minerals that induced a drop in the level of atmospheric CO₂ and contributed, via the atmospheric greenhouse effect, to global cooling and the initiation of the most long lived and a really extensive glaciation of the past 550 million years. Sedimentary burial of the microbiologically resistant remains of the plants resulted during the Permo-Carboniferous in both further lowering of CO₂ and in elevation of atmospheric O₂. Evidence of changes in CO₂ and O₂ are provided by mathematical models, studies of paleosols, fossil plants, fossil insects, and the effects of modern plants on silicate weathering, and by laboratory studies of the effects of changes in O₂ on plants and insects. To cite this article: R.A. Berner, C. R. Geoscience 335 (2003).     

Environmental significance of C/C and O/O ratios of modern land-snail shells from the southern great plains of North America

¹³C/¹²C and ¹⁸O/¹⁶O ratios of aragonite shells of modern land snails from the southern Great Plains of North America were measured for samples from twelve localities in a narrow east-west corridor that extended from the Flint Hills in North Central Oklahoma to the foothills of the Sangre de Cristo Mountains in Northern New Mexico, USA. Across the study area, shell δ¹⁸O values (PDB scale) ranged from −4.1‰ to 1.2‰, while δ¹³C values ranged from −13.2‰ to 0.0‰. δ¹⁸O values of the shell aragonite were predicted with a published, steady state, evaporative flux balance model. The predicted values differed (with one exception) by less than 1‰ from locality averages of measured δ¹⁸O values. This similarity suggests that relative humidity at the time of snail activity is an important control on the δ¹⁸O values of the aragonite and emphasizes the seasonal nature of the climatic information preserved in the shells. Correlated δ¹³C values of coexisting Vallonia and Gastrocopta suggest similar feeding habits and imply that these genera can provide information on variations in southern Great Plains plant ecology. Although there is considerable scatter, multispecies, transect average δ¹³C values of the modern aragonite shells are related to variations in the type of photosynthesis (i.e., C₃, C₄) in the local plant communities. The results of this study emphasize the desirability of obtaining isotope ratios representing averages of many shells in a locale to reduce possible biases associated with local variations among individuals, species, etc., and thus better represent the “neighborhood” scale temporal and/or spatial environmental variations of interest in studies of modern and ancient systems.     

Laboratory study of self-potential signals during releasing of CO2 and N2 plumes

Carbon Capture Sequestration (CCS) projects require, for safety reasons, monitoring programmes focused on surveying gas leakage on the surface. Generally, these programmes include detection of chemical tracers that, once on the surface, could be associated with CO₂ degassing. We take a different approach by analysing feasibility of applying electrical surface techniques, specifically Self-Potential. A laboratory-scale model, using water-sand, was built for simulating a leakage scenario being monitored with non-polarisable electrodes. Electrical potentials were measured before, during and after gas injection (CO₂ and N₂) to determine if gas leakage is detectable. Variations of settings were done for assessing how the electrical potentials changed according to size of electrodes, distance from electrodes to the gas source, and type of gas. Results indicated that a degassing event is indeed detectable on electrodes located above injection source. Although the amount of gas could not be quantified from signals, injection timespan and increasing of injection rate were identified. Even though conditions of experiments were highly controlled contrasting to those usually found at field scale, we project that Self-Potential is a promising tool for detecting CO₂ leakage if electrodes are properly placed.