合成碳羟基磷灰石对水中苯胺的吸附机理

利用红外光谱、扫描电子显微镜、X射线衍射仪等测试技术对脲素和蛋壳制成的碳羟基磷灰石(carbonate hydroxylapatite,CHAP)样品表面化学组成进行了表征,并考察了pH值、吸附时间和苯胺浓度对CHAP吸附水中苯胺的影响,以及其吸附动力学和热力学特征。结果表明:当pH=6,吸附时间为60min,苯胺初始浓度为30mg/L,CHAP对苯胺的吸附效果更好。该过程可用Langmuir Freundlich等温式进行描述,但更符合Freundlich经验公式。分别采用准一级动力学模型和准二级动力学模型考察吸附动力学行为,2个模型与实验数据之间有很好的相关性。吸附热力学行为表明该吸附过程是放热和自发的。     

纳米羟基磷灰石粉体的制备及其对苯酚吸附研究

应用化学沉淀法制备得到纳米羟基磷灰石(n-HAp)粉体,并研究了n-HAp粉体对水溶液中苯酚的吸附性能。考查了n-HAp粉体的用量、溶液的pH值和苯酚的初始浓度对苯酚吸附量的影响。研究结果表明:n-HAp对苯酚具有很好的吸附效果,在2h内即可达到吸附平衡;饱和吸附量达到11.0mg/g;pH值对吸附性能的影响明显,在强酸和强碱情况下能有效提高n-HAp对苯酚的吸附量;苯酚的去除率随粉体用量的增加而提高。     

碳羟基磷灰石对铅离子吸附性能研究

采用共沉淀法合成碳羟基磷灰石粉体,对其进行铅离子吸附性能测试,结果表明,当pH=3,吸附温度在40℃,吸附时间达到1小时,吸附率达到95％,吸附效果最好,且吸附不产生二次污染.     

碳羟基磷灰石除废水中六价铬的吸附性能研究

利用废弃蛋壳为原料,水热法合成碳羟基磷灰石(CHAP)吸附剂,用它去除含铬废水中六价铬,研究了pH、六价铬初始质量浓度、吸附时间等对吸附效果的影响.结果表明:常温下,溶液pH为3、碳羟基磷灰石用量为5 g/L时,对100 mL 50 mg/L的六价铬吸附速度较快,30 min基本上达到吸附平衡,去除率为98.3%,最大吸附量高达29.85 mg/g.用Langmuir和Freundlich方程拟合碳羟基磷灰石对六价铬的吸附等温式,相关系数分别为0.998 4和0.922 6,说明这两个方程都较好地描述吸附过程.通过氢氧化钠或硫酸浸泡和微波加热处理对吸附后的碳羟基磷灰石进行再生试验,再生率高达94.3%和94.8%.     

碳羟基磷灰石/钾长石复合材料对镍的吸附性能研究

以钾长石为原料,用液相合成法制备碳羟基磷灰石/钾长石吸附剂（CHAK）去除水中的重金属镍,用静态吸附实验考察了CHAK添加量、溶液初始pH、吸附时间、镍初始浓度等因素对镍去除效果的影响,并结合动力学及热力学拟合探究吸附机理。结果表明：随着CHAK量的增加,对Ni ²⁺的去除率增加,但吸附量会降低;溶液pH=6时吸附效果达到最佳;吸附时间为10 h时吸附达到平衡;Ni ²⁺溶液的初始质量浓度为50~4 000 mg/L时,CHAK对Ni ²⁺的吸附量呈先增长后平稳趋势,饱和吸附量与原材料相比增大7.1倍。动力学及热力学拟合结果显示：准二级模型更符合描述该吸附行为。ΔH>0,表明该吸附过程为吸热反应,升温有利于吸附。ΔG<0,表明该反应能自发进行。     

羟基磷灰石的表面特性

本文综述了羟基磷灰石（ＨＡＰ）的表面结构、表面能、表面电荷等特性，总结了ＨＡＰ对无机阴、阳离子，短链有机物，聚合物的作用规律及其对ＨＡＰ晶体生长和形态的影响，并进一步概括了ＨＡＰ在悬浮体系中的团聚和解聚现象，以及这种现象的形成原因。     

碳羟基磷灰石处理人工湖水的研究

采用自制的碳羟基磷灰石(CHAP)作为吸附剂处理人工湖水,分别考察了pH值、作用时间、吸附剂用量、温度等因素对色度和COD去除效果的影响.结果表明,在常温、pH值为5.5、吸附时间为60 min、CHAP用量为10 g·L-1的务件下,CHAP对人工湖水的色度和COD去除率分别达到82%、81%.CHAP吸附人工湖水中COD的机理符合一级动力学规律,动力学方程为In(co/c)=0.5013t 0.9136,反应速率常数k=0.5013 h-1,半衰期t1/2=1.38 h.     

含硅碳羟基磷灰石的制备及其对锰离子的吸附性能

以废弃蛋壳为原料水热法合成含硅碳羟基磷灰石(Si-CHAP)粉体,采用红外光谱对其进行分析,测定不同温度下Mn2+在Si-CHAP粉体上的吸附等温线、吸附动力学曲线及热力学参数. 结果表明,Langmuir方程可较好地描述Mn2+在Si-CHAP粉体上的吸附平衡,20, 30和40℃下最大吸附容量分别为38.91, 41.49和43.10 mg/g;吸附动力学规律可用准二级动力学模型表示,相关系数高达0.99以上;热力学参数表明此吸附过程为自发吸热过程.     

碳羟基磷灰石处理有机废水的研究

采用自制的碳羟基磷灰石（CHAP）作为吸附剂处理制药有机废水,分别考察了pH值、作用时间、吸附剂用量、温度等因素对色度和COD去除效果的影响。实验结果表明：在常温、pH为6、吸附时间为60min、CHAP用量为18mg／L的条件下,对有机废水的色度和COD去除率分别达到84％、81．5％,吸附容量达72．89mg／g。CHAP吸附有机废水中的COD机理符合Langrnuir方程,吸附反应快速、自发地进行,属于吸热反应。     

负载羟基氧化铁改性滤料对苯酚吸附研究

负载铁氧化物石英砂对苯酚的吸附具有一定的效能.负载羟基氧化铁对苯酚的吸附吸附苯酚等温线用Langmuir方程比用Freundlich方程拟合得更好,相关系数R2为0.992.吸附总量随着苯酚含量的增加而增大,但是吸附率下降.同时研究了pH和腐殖酸、CO32-、Ca2+含量对苯酚吸附量的影响,结果表明,低pH有利于苯酚的吸附,苯酚吸附率随着腐殖酸、CO32-含量的增大而减小.Ca2+使苯酚吸附量产生不规则的影响,可能与羟基氧化铁表面的复杂配合反应有关.     

焙烧层状氢氧化镁铝吸附脱除水中苯酚的研究

用层状氢氧化镁铝的焙烧产物吸附水中苯酚,研究了吸附剂用量、吸附时间、温度、溶液pH值等条件对吸附性能的影响。结果表明,吸附主要发生在90min内,吸附量随着温度的升高而增加。溶液初始pH值对吸附影响较大,pH值在6～11范围内吸附效果较酸性时好。吸附符合Langmiur等温线,饱和吸附量为0.557mg/g。     

Adsorption of Phenol and Basic Dye on Carbon Nanotubes/Carbon Fabric Composites from Aqueous Solution

The liquid-phase adsorption of phenol and dye (basic violet 10) onto carbon nanotube (CNT)-activated carbon fabric (ACF) composites, prepared by a catalytic chemical vapor deposition (CCVD) approach, has been investigated. The CCVD technique enables the decoration of CNTs on microscaled ACFs, creating a hierarchy CNT-ACF composite. The as-grown nanotubes were found to have a tortuous shape and to be several micrometers in length. The deposition of CNTs efficiently shifts the micropore size distribution of ACFs to mesoporosity. The adsorption isotherms for phenol and BV10 on ACF and CNT-ACF adsorbents are well characterized by the Dubinin-Radushkevich and Langmuir models. The surface accessibility, the equilibrium rate constant, and the adsorption energy are significantly enhanced due to the deposition of CNTs, as analyzed by these models. Accordingly, the existence of CNTs on ACF adsorbent plays a positive role in facilitating pore accessibility to adsorbate and providing more adsorptive sites for the liquid-phase adsorption.     

双吡啶盐改性膨润土的制备及其对苯酚的吸附性能研究

以六亚甲基双吡啶盐(HEMBP)为改性剂对膨润土(B)进行改性,利用XRD,BET,FT-IR和SEM对所得有机改性膨润土(HEMBP-B)的结构进行表征,并优化了改性条件,发现在HEMBP吡啶阳离子添加量为1.0 CEC,液固比(L/S)为50 mL:1 g,时间t为3 h,温度T为60℃,pH为6.26(自然值)的改性条件下,HEMBP在膨润土上的吸附量最大并达到平衡。同时,以该条件下制备的HEMBP-B为吸附剂,在T为45℃,t为2.5 h,pH为6.46(自然值)时,HEMBP-B对初始浓度为50 mg L 1苯酚溶液的去除率可达80%左右,且吸附等温线符合Freundlich方程。该研究不仅丰富了处理含酚废水的吸附剂种类,而且也为短链吡啶盐改性黏土在污水处理方面的应用提供了参考依据。     

PbO-Yb2O3催化苯酚与碳酸二甲酯的酯交换反应

制备了一系列固体催化剂用于苯酚(PhOH)与碳酸二甲酯(DMC)酯交换合成碳酸二苯酯(DPC).其中,铅镱复合氧化物催化剂活性较高,能多次回收使用.用正交实验方法详细研究了该催化剂焙烧温度、催化剂组成及反应温度等影响因素.实验结果表明:选择铅镱物质的量比为2∶1,700℃下焙烧的催化剂,在n(PhOH)∶n(DMC)=2∶1,反应温度170℃,反应16 h时,得DMC转化率56.87%,DPC产率17.10%.碳酸甲苯酯(MPC)产率33.24%.该催化剂多次回收使用后仍有较好的活性.     

苯酚和二氧化碳合成碳酸二苯酯的热力学分析

根据经典热力学原理,计算了苯酚和二氧化碳合成碳酸二苯酯的反应在不同温度下的摩尔吉布斯自由能变化。结果表明,高温有利于碳酸二苯酯的生成;提高二氧化碳压力对平衡有利;计算结果与实验数据吻合,但实验收率偏低。     

Adsorption of Phenol on Different Activated Carbons Prepared from Date Pits

The potential use of different activated carbons (ACs) prepared from dates pits and phosphoric acid for the removal of phenol from aqueous solutions was investigated. Date pits were converted into five different types of activated carbons by air and phosphoric acid activation. The specific surface area (BET) of the prepared ACs varied from 794 m²/g, for the phosphoric acid:date pit ratio of 5:1, to 1707 m²/g for a ratio of 2:1. Batch adsorption experiments revealed that the adsorption of phenol varied among all of the prepared ACs, where the 2:1 AC showed the highest uptake. Equilibrium pH studies showed that the phenol removal was pH dependent and the maximum phenol uptake occurred at an equilibrium pH of 3.0. Dynamics studies indicated that the initial uptake of phenol on 2:1 AC at pH 4 was rapid, where 80% of the maximum uptake was achieved during the first 30 minutes; both surface adsorption and intraparticle diffusion were involved in the adsorption process and the data followed the pseudo second-order reaction. The equilibrium adsorption data of phenol on 2:1 AC at solution pH 3 was best described by the Redlich-Peterson, Sips, and Langmuir models.     

纤维对苯酚的吸附性能研究

研究了自制的纤维对苯酚的吸附热力学特性,测定了不同温度下的吸附等温线,结果显示,纤维对水溶液中的苯酚有较高的吸附能力,吸附过程符合Langmuir和Freundlich方程,吸附焓变为正值,表现为吸热的吸附过程。     

Decontamination of Manganese and Phenol from Aqueous Media by Sunflower Stems

Development of new economically feasible eco-friendly products from agricultural wastes for the removal of pollutants from water is the objective of many researchers. In this study, attempts have been made to use sunflower stems for the removal of Mn(II) and phenol from water. An ion-exchange resin was fabricated through the hydrolysis of graft copolymer of pretreated sunflower stem with acrylamide that was made by Fe²⁺/H₂O₂ initiator. Factors affecting the grafting reaction, such as grafting time and temperature as well as initiator and monomer concentration, were studied. The hydrolysis under basic/acidic conditions was also studied. In addition to grafting, the charring of sunflower stem was studied at 400°C. Our results showed that the optimum condition for grafting was sunflower stem: monomer = 1:3, at 30°C, weight of Fe²⁺/2 g bleached sunflower stem = 0.5 g, and grafting time 2 h. The maximum removal capacity for Mn(II) was found with the alkali and acidic hydrolyzed grafted sunflower stem, while the charred sunflower stem had the highest efficiency for removal of phenol from water.