共查询到19条相似文献，搜索用时 93 毫秒
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采用微波法对蜜桔皮中黄酮类化合物进行提取。将单因素分析与正交试验相结合,得到微波法提取蜜桔皮中黄酮类化舍物的最佳工艺条件：提取剂乙醇体积分数为50％;微波功率为560w;提取时间为4min;料液比（g／mL）为1：30。每克蜜桔皮中提取黄酮类化合物为0．52mg,回收率为93．3％。在最佳参数组合下,桔皮黄酮提取量可这最大,并且研究了AB-8大孔吸附树脂对桔皮黄酮的吸附和解吸附特性和纯化效果,结果表明AB-8大孔树脂可用与桔皮中总黄酮的纯化。 相似文献
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利用硅藻土负载羟基氧化铁颗粒作吸附剂对六价铬进行吸附和解吸附实验,探讨了硅藻土负载羟基氧化铁对六价铬的吸附机制和固体浓度效应。实验结果表明：在实验条件下,当吸附剂的用量从0.05 g增加到0.2 g时,六价铬的吸附量从23940.124μg/g降低到8575.415μg/g,吸附剂对Cr6＋的吸附存在明显的固体浓度（Cs）效应。吸附滞后角随着Cs 的增加而减小,吸附反应的可逆性增大。将实验数据分别用Languir和Freundlich吸附模型进行拟合,发现Freundl-ich吸附模型对实验数据拟合效果较好,表明该吸附反应以单分子层吸附为主。 相似文献
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无机—有机柱撑蒙脱石对苯酚的吸附 总被引：55，自引：1，他引：54
分别用无机－有机改性柱撑蒙脱石对苯酚进行吸附试验,研究它们吸附苯酚的适宜条件圾吸附等温线（２５℃）,结果表明,用表面活性剂改性的柱撑蒙脱石,能大幅度提高对苯酚的吸附能力,柱撑蒙脱石对苯酚的吸附能力主要取决于改性粘土吸附剂的微孔结构和表面组分,而不仅仅依赖于表面积,经５００℃高温灼烧后柱撑蒙脱石柱结构及层间距（１．８３ｎｍ）稳定,因而柱撑蒙脱石可再生循环使用,是一种潜在的吸附环境污染物的物质。 相似文献
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地下水中的砷污染物对人类造成了严重威胁。茶真菌是在红茶发酵期间产生的一种废料。本文就茶真菌吸附地下水中金属离子的能力进行了研究。在印度孟加拉邦的Kolkata地区采集了地下水样品，并分别使用高压灭菌的茶真菌簇和Fecl3处理过的茶真菌簇，对地下水样品中的铁（Ⅱ）、砷（Ⅲ）和砷（Ⅴ）进行去除。生物吸附速率随接触时间（吸附剂和金属离子接触的时间）和吸附剂剂量的增加而增大。当接触时间为30分钟时，高压灭菌的茶真菌簇和Fecl3处理过的茶真菌簇去除了100％的铁（Ⅱ）和砷（Ⅲ）；当接触时间为90分钟时，高压灭菌的茶真菌簇和Fecl3处理过的茶真菌簇去除了77％的砷（Ⅴ）。在去除地下水样品中的金属时，吸附剂的最佳剂量为1．0克／50毫克。研究结果表明，在去除地下水中的砷（Ⅲ）和砷（Ⅴ）时，Fecl3处理过的茶真菌簇是最有效的生物吸附剂；在去除地下水中的铁（Ⅱ）时，高压灭菌的茶真菌簇是最有效的生物吸附剂。 相似文献
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以氧化还原共沉淀的方法将铁锰复合氧化物负载于坡缕石黏土表面,制备负载型吸附剂,由静态吸附实验研究了吸附剂对磷的吸附性能,探讨了吸附的动力学特征、热力学参数和吸附机理。结果显示,吸附剂对磷的吸附受溶液初始pH值、吸附时间及温度的影响,在中性条件下吸附平衡时间为90 min,pseudo-second-order吸附动力学方程能较好描述吸附过程,吸附表观活化能为11.76 k J/mol;吸附等温线与Freundlich方程的拟合结果略优于Langmuir方程,由Langmuir方程得到最大吸附量为26~31 mg/g。吸附焓变为9.29 k J/mol,吸附熵变为正值,自由能变为-4.3~-5.8 k J/mol,吸附作用有多层不均匀吸附的性质,同时包含物理作用和化学作用,但不属强的化学键作用。 相似文献
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多聚磷酸盐（Poly-P）是一类非常重要的无机磷酸盐,在自然界广泛存在,研究多聚磷酸盐在自然界的迁移转化对理解磷的生物地球化学循环至关重要。矿物—溶液界面的吸附反应是控制元素在沉积物和土壤中迁移转化的一个关键过程,因此本研究选取在自然界广泛分布的勃姆石（Boehmite）,即羟基氧化铝作为吸附剂,研究了勃姆石在不同初始磷浓度、不同pH条件下对多聚磷的吸附行为和吸附机制。实验结果表明：在实验条件下,随着初始磷浓度的增加,勃姆石对多聚磷的吸附量也随之增加,吸附率均接近100%;而随着pH的升高,勃姆石对多聚磷的吸附量逐渐降低。本研究进一步采用XRD、SEM、31P NMR技术对吸附产物进行了表征,核磁共振结果表明勃姆石吸附多聚磷的过程中伴随着多聚磷水解,长链中间的P-O-P键随机断裂,生成了许多短链多聚磷和正磷酸根,两者以内圈络合的形式吸附在勃姆石表面。 相似文献
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坡缕石对Zn^2＋的吸附性能及吸附工艺条件优化研究 总被引：1，自引：2，他引：1
从坡缕石粘土提纯人手，进行了坡缕石吸附Zn^2 的实验研究，结果表明坡缕石对水中Zn^2 的吸附性能主要受振荡速度、吸附时间、溶液pH值、吸附剂用量等因素影响，30℃时坡缕石对Zn^2 的等温吸附曲线同时符合Langmuir方程和BET方程。在本实验条件下，坡缕石对水中的Zn^2 (20mL，Zn^2 浓度均为50mg／L)的最佳吸附工艺条件为：振荡速度150r／min，吸附时间120min，吸附剂用量0．120g，溶液pH为6．2，此条件下去除率达到T95．5％。 相似文献
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In this work, clinoptilolite was modified with conducting polyaniline polymer and then the nanocomposite was used as an adsorbent for methyl orange (MO) as a model dye. Cations located in clinoptilolite structure like Na+, K+, Mg2+, Ca2+ were exchanged with anilinium cations and then the polymerization of anilinium cations in and outside of the clinoptilolite channels resulted in the formation of polyaniline/clinoptilolite nanocomposite. The resulted nanocomposite was used for the removal of MO from aqueous solution. The effect of various factors like contact time, concentration of dye as well as the amount of adsorbent on the removal efficiency of dye was investigated. The adsorption isotherms were investigated. It was found that the equilibrium adsorption data were well described by the Langmuir isotherm model. The kinetic studies indicated that the adsorption process was controlled by pseudo-second-order equation. High adsorption capacity and low contact time as well as the low cost of modified clinoptilolite proved that it is an efficient adsorbent for the removal of MO from aqueous solutions. 相似文献
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WILLIAM CAVAZZA 《Sedimentology》1989,36(6):1077-1090
The Stilo-Capo d'Orlando Formation (SCO Fm) is a Miocene clastic unit nonconformably covering the basement of the southern portion of the Calabria-Peloritani Arc (CPA), a small-scale terrane which was accreted onto the Apennines-Maghrebides orogenic system during Neogene time. The SCO Fm is composed of conglomerate, sandstone and mudrock deposited in a marine environment through the action of gravity currents. Detrital modes of sandstones and conglomerates of the SCO Fm indicate a local provenance. In fact, petrological parameters can be matched directly with nearby basement lithologies. Two petrofacies with distinctive parameters are present. A northern petrofacies is predominantly composed of plutonic and low-grade metamorphic detritus, and was derived from the Serre massif, which is mostly made of late Hercynian plutons intruded into metasedimentary rocks. A southern petrofacies is mostly composed of metamorphic detritus and was derived from the Aspromonte and the Peloritani Mountains, which are predominantly composed of middle-to high-grade metamorphic rocks. Petrological results place important constraints on the geodynamic evolution of the CPA. According to several authors, the arc is composed of two sectors (microterranes) with different geological histories and partly composed of contrasting rock types, whose timing of juxtaposition is debated (Early Cretaceous against middle-late Miocene; that is, much before or soon after deposition of the SCO Fin). The SCO Fm crops out only in the southern sector of the CPA and does not contain any detritus derived from the northern sector, in spite of a favourable sediment palaeodispersal system. This fact indicates that the amalgamation of the two sectors probably took place after deposition of the SCO Fm. 相似文献
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Adsorptive removal of eight heavy metals from aqueous solution by unmodified and modified agricultural waste: tangerine peel 总被引：1，自引：0，他引：1
Š. Abdić M. Memić E. Šabanović J. Sulejmanović S. Begić 《International Journal of Environmental Science and Technology》2018,15(12):2511-2518
Analysis was carried out using tangerine peel aiming its use as a potential adsorbent of eight heavy metal ions (Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) from aqueous solution. This agricultural waste was tested both in its untreated and also chemically modified form. Based on Fourier transformation infrared spectra, a comparison of biosorbent structure before and after chemical treatment was made. Batch adsorption tests were conducted at different pH and mass of sorbent to examine the influence on the effectiveness of simultaneous removal of tested ions. Kinetic studies were conducted at optimum pH 5.0 and sorbent dosage 300 mg. The pseudo-second-order kinetic model best fit the experimental data with high correlation coefficients (r2 > 0.9997). By optimizing listed parameters, high removal efficiencies (> 89%) were achieved. According to the results obtained in this study, the remediation of water polluted with heavy metals could be done using modified tangerine peel as an agricultural waste material. 相似文献
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I. Hossain N. Anjum T. Tasnim 《International Journal of Environmental Science and Technology》2016,13(3):843-848
Activated carbon is the adsorbent commonly used to remove arsenic from contaminated water. However, the problem is that it is not always available everywhere and considered expensive in developing countries. An inexpensive alternative to activated carbon can therefore aid the adequate treatment of contaminated water. Tea waste, water hyacinth and banana peel are investigated extensively in this study as the inexpensive alternative. Tea waste treated with a right proportion of aqueous FeCl3 reagent is found to have substantially higher arsenic removing capacity (which is quantified by arsenic concentrations measured employing Double Beam Atomic Absorption Spectrophotometer) than the other two. The comparison made subsequently between tea waste and activated carbon reveals the feasibility of the utilization of tea waste. The arsenic removing capacity of tea waste treated with the right proportion of aqueous FeCl3 reagent is found to be equal to that of the activated carbon treated with the same reagent over the continuous operative time of 2 h. The tea waste treated rightly with the same reagent also removes arsenic at acceptable capacities over extended operative times such as 4–6 h. It is therefore proposed to consider tea waste as the inexpensive alternative to activated carbon in treating arsenic contaminated water. 相似文献
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剥离断层—50矿床的主控因素 总被引：1，自引：0，他引：1
燕山晚期的拉张构造环境，在深断裂带或裂陷带两侧形成了各种不同层次的拆离滑脱，包括剥离断层。信江裂陷带南侧的Ｆ１５剥离断层（系统）控制了５０矿床的矿质来源，矿质沉淀及矿体定位。该断层是控矿的主导因素。文中还讨论了剥离断层的找矿意义。 相似文献
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在赣南稀土高背景区和稀土低背景区不同地质环境脐橙果同,系统采集岩、土、脐橙植物样,用ICP-MS法测定样品中15种稀土元素的含量,并对稀土元素在岩石、土壤和脐橙植物体内的分布、迁移、累积特征进行了研究.结果表明:a.基岩的稀土元素含量影响(决定)土壤各层位的稀土元素含量;b.土壤环境中稀土元素含量高低直接影响脐橙植物体稀土元素含量,但不完全成正比;c.基岩的稀土元素配分模式基本上贯穿土壤各层位、脐橙植物体各器官;d.岩、土、脐橙三大环节稀土无素的百分含量,总的趋势是轻稀土比重逐渐增高,重稀土比重逐渐降低,但重稀土在脐橙植物体末稍器官比例有所增加;e.岩土脐橙生态系统立体刮面中,稀土元素的垂直方向运动呈向量关系;f.由于土壤-植物壁垒作用和脐橙植物体自身的选择性吸收、控制性积累功能,高、低稀土背景区脐橙果肉的稀土含量均低于国家食品卫生限量标准. 相似文献
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S. Kahu A. Shekhawat D. Saravanan R. Jugade 《International Journal of Environmental Science and Technology》2016,13(9):2269-2282
Microwave-assisted tetrabutyl ammonium-impregnated sulphate-crosslinked chitosan was synthesized for enhanced adsorption of hexavalent chromium. The adsorbent obtained was extensively characterized using Fourier transform infrared, X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray studies. Various isotherm models such as Langmuir, Freundlich and Dubinin–Radushkevich were studied to comprehend the adsorption mechanism of hexavalent chromium by the adsorbent. Maximum adsorption capacity of 225.9 mg g?1 was observed at pH 3.0 in accordance with Langmuir isotherm model. The sorption kinetics and thermodynamic studies revealed that adsorption of hexavalent chromium followed pseudo-second-order kinetics with exothermic and spontaneous behaviour. A column packed with 1 g of adsorbent was found to give complete adsorption of Cr(VI) up to 900 mL of 200 mg L?1 solution which discerns the applicability of the adsorbent material for higher sample volumes in column studies. The effective adsorption results were obtained due to both ion exchange and ion pair interaction of adsorbent with hexavalent chromium. Greener aspect of overall adsorption was regeneration of the adsorbent which was carried out using sodium hydroxide solution. In the present study, the regenerated adsorbent was effectively reused up to ten adsorption–desorption cycles with no loss in adsorption efficiency. 相似文献