表面功能化活性炭对水溶液中汞离子的吸附

利用硝酸氧化改性和氨还原改性实现活性炭表面功能化,并通过静态吸附实验研究了改性前后活性炭对水溶液中汞离子的吸附性能。硝酸改性使得活性炭表面含氧官能团数量增多,氨改性后成功在活性炭上引入含氮官能团。实验结果表明在pH值为4～7的范围内有较好的吸附效果。吸附等温线和吸附动力学结果表明活性炭表面功能化可以提高对水溶液中汞离子的吸附性能。活性炭表面含氧官能团和含氮官能团与汞离子发生离子交换和配位络合作用。     

改性活性炭脱除二氧化碳中的微量苯

将工业废气中的CO2回收利用,使之变废为宝具有重要的意义。研究了活性炭(AC)分别经湿氧化和N2还原改性后对苯吸附性能,并测定了改性活性炭的孔结构和表面官能团。结果表明,AC经N2还原改性能增大其比表面积,减少表面含氧官能团,增强其表面非极性,有利于苯的吸附。孔径分布是影响苯吸附的主要因素,吸附剂的孔径分布在0.6nm范围内时,有利于对苯的吸附。     

活性炭液相吸附脱除二甲基二硫醚

通过椰壳活性炭对模拟硫酸盐松节油进行液相吸附脱硫的研究,考察了活性炭的结构和表面化学对活性炭吸附的影响。通过Gaussian03计算模拟油中各化合物的化学硬度,根据软硬酸碱理论解释表面化学对该吸附过程的影响。同时考察了活性炭吸附过程的热力学性质。结果表明,由于吸附体系中的二甲基二硫醚和莰烯的化学硬度相接近,活性炭表面的含氧官能团的变化对吸附性能影响不大,但活性炭比表面积和孔结构的变化对吸附性能的影响较为明显;等温吸附平衡数据符合Freundlich等温吸附模型,热力学数据显示该活性炭吸附过程是一个放热、混乱度降低的自发物理吸附过程。     

活性炭表面热氧化对其吸附二苯并噻吩性能影响

本文主要研究活性炭表面氧化对其吸附二苯并噻吩性能的影响。将活性炭在不同低温下氧化制得表面氧化活性炭，用静态吸附法进行了二苯并噻吩在初始及氧化活性炭上的吸附等温线，应用Langmuir方程对吸附等温线进行拟合，用漫反射红外谱（DRIFTS）表征活性炭表面含氧基团，用Boehm滴定测定活性炭表面官能团含量，讨论了活性炭表面化学性质对其吸附二苯并噻吩的影响。结果表明：活性炭表面酸性含氧基团对二苯并噻吩的吸附有重要影响，酸性含氧基团越多，其吸附量越大。低温气相氧化活性炭提高了活性炭表面酸性含氧基团，提高了其对二苯并噻吩的吸附。氧化温度越高，其表面含氧基团含量越多，其对二苯并噻吩的吸附量也越大。Langmuir吸附等温线可适用于描述二苯并噻吩在活性炭表面上的吸附。     

HNO3改性活性炭对Cr(Ⅵ)的吸附性能及机理

活性炭的吸附性能与其表面化学密切相关,本研究为讨论活性炭表面氧化改性对其Cr(Ⅵ)吸附特性的影响,分析了Cr(Ⅵ)吸附过程与活性炭表面化学性质的关系,阐释吸附机理。结果表明,与未改性活性炭相比,硝酸氧化改性后活性炭对溶液中Cr(Ⅵ)的吸附性能提高,且改性后活性炭的比表面积和孔容积降低,表面的羧基、内酯基和酚羟基等酸性含氧官能团的数量增多。改性活性炭对Cr(Ⅵ)的吸附过程可用Langmuir、Freundlich、D-R和Temkin4种吸附模型模拟,吸附动力学数据与拟二级动力学模型吻合。采用X射线光电子能谱(XPS)表征了改性前后活性炭的表面化学性质。Cr(Ⅵ)在活性炭上的吸附机理主要为静电吸引、还原和配位络合等,与Cr(Ⅵ)发生络合作用的是活性炭表面含氧官能团。     

硝酸氧化改性活性炭对Cr(Ⅵ)吸附性能的研究

采用一定浓度的浓硝酸氧对活性炭颗粒进行表面氧化处理,研究了改性对活性炭吸附Cr（Ⅵ）性能。的影响。结果表明,改性使活性炭表面含氧官能团显著增加,对Cr（Ⅵ）的吸附作用增强。考察了接触时间、pH,温度等条件对吸附效果的影响,并对吸附机理进行了初步探讨。     

有机/无机酸改性兰炭基活性炭及其对焦化废水的吸附研究

兰炭因其固定碳和化学活性高,且保留了低变质煤丰富的微孔结构,是一种优质且廉价的活性炭原料。但兰炭末制成的兰炭基活性炭具有孔径分布无序、表面化学性质局限等缺点,限制了其应用效果,而化学法改性可以弥补这一不足。笔者研究对比了无机酸和有机酸改性对兰炭基活性炭孔隙结构和表面化学性质的影响。常温下,分别用硝酸、磷酸、草酸和乙酸溶液对水蒸气活化制备的兰炭基活性炭进行改性,采用碘吸附试验、N2吸附/脱附试验、扫描电子显微镜和Boehm滴定等方法考察改性过程对活性炭孔隙结构和表面化学性质的影响,并对焦化废水进行吸附,分别研究了吸附剂投加量、吸附时间和转速对吸附效果的影响,用Langmuir和Freundlich模型模拟等温吸附过程。结果表明:改性后的兰炭基活性炭表面亲和力大的活性点由于受到酸的刻蚀发生了扩孔作用,导致其碘吸附值、比表面积和孔结构参数均降低,又因为活性炭边缘的高活性碳原子遇酸氧化后会结合氧原子形成含氧官能团,故表面含氧官能团含量升高,且氧化性越强的酸,结合的氧原子越多,硝酸改性后含氧官能团升高最明显,含量是改性前的2.41倍。焦化废水吸附试验表明,经酸改性后的兰炭基活性炭对焦化废水的吸附效果明显优于改性前,其中无机酸改性较有机酸更好,硝酸改性效果最佳,COD去除率比改性前最多可提升31.34%。这是因为焦化废水中污染物的主要是有较大分子量和分子直径的有机污染物,而酸改性使兰炭基活性炭平均孔径增加,中大孔比例提升,这有利于大分子有机污染物被吸附,而且改性后活性炭表面所增加的含氧官能团也提高了对污染物的亲水性和对极性有机物的亲和力。等温吸附试验表明,318 K条件下,50 m L焦化废水中加入4 g硝酸改性兰炭基活性炭吸附90 min后,COD去除率可达86.79%,吸附过程符合Langmuir模型。     

怀炭表面化学

活性炭表面化学特性对其吸附性能产生显著影响。主要从以下几方面对活性炭表面化学进行综述：（１）活笥炭表面的主要含氧官能团和含氮官能团、（２）活性炭表面化学的分析测试技术;（３）活性炭活性及表面改性技术。     

活性炭表面化学

活性炭表面化学特性对其吸附性能产生显著影响．主要从以下几方面对活性发表面化学进行综述：（１）活性炭表面的主要含氧官能团和含氮官能团;（２）活性炭表面化学的分析测试技术;（３）活性炭活化及表面改性技术．     

活性炭微观结构调控与甲苯二胺选择性吸附研究

从活性炭、硅藻土、ZSM-5分子筛、人造沸石等常见多孔材料中,筛选出吸附性能较优的活性炭作为吸附剂,通过酸、碱等改性方法对活性炭孔结构和表面官能团进行调控,并采用静态吸附实验研究了改性活性炭吸附分离TDA焦油的效果。结果表明,活性炭的孔结构主要影响活性炭对甲苯二胺焦油的总吸附容量,而活性炭的表面官能团则显著影响TDA的选择性,酸性基团有利于增强活性炭对TDA的选择性。在最优条件下,CH₃COOH改性活性炭对TDA的选择性达到98%以上,改性活性炭吸附过程受到化学吸附因素控制。     

Pilot study of the removal of THMs, HAAs and DOC from drinking water by GAC adsorption

The objective of this pilot study was to evaluate the performance of a GAC postfilter-adsorber for the removal from the drinking water of Athens, Greece, of the two main groups of chlorination by-products, trihalomethanes (THMs) and haloacetic acids (HAAs), as well as of dissolved organic carbon (DOC). The analyses performed during the whole operation period (638 days) showed that the GAC breakthrough capacity for DOC was much higher than the capacity for total HAAs, which was higher than that for total THMs. The removal of THMs and the most part of the removal of HAAs and DOC should be attributed to adsorption by GAC, while that of a smaller part of HAAs and DOC may be attributed to biodegradation in the adsorber bed, where dechlorination, caused catalytically by the carbon surface, favoured microbial growth. Additionally, the GAC postfilter-adsorber showed a much higher adsorption efficiency than a GAC filter-adsorber, due to the smaller size of the carbon and the lower hydraulic loading rate. Also, observed desorption incidents of THMs (mainly) and HAAs, especially during the postfilteradsorber operation, were favoured by the same factors. Formation of THMs within the GAC bed was also indicated by the mass balance of total THMs during the whole cycle.     

活性炭表面化学改性技术的研究进展与展望

活性炭表面官能团和杂原子的数量与种类是影响活性炭吸附性能的重要因素。国内外研究表明,通过对活性炭进行表面改性可以显著改善活性炭对特定物质的吸附性能。文章简要介绍了活性炭的物理和化学性质,并从活性炭材料的表面化学性质方面论述了近年来国内外在活性炭材料改性方面的研究进展,最后提出了活性炭表面改性技术的发展方向和趋势。     

三种VOCs物性对其在活性炭上吸附行为的影响

为了探讨VOC物性对活性炭吸附行为的影响,对活性炭表面物化性质进行了表征.并以甲苯、丙酮、二甲苯为吸附质,在同等实验条件下进行了固定床吸附实验.实验结果显示活性炭对3种VOCs的吸附量为二甲苯＞甲苯＞丙酮.将实验结果与VOC物性进行关联分析,结果表明:活性炭对有机气体的吸附量随着吸附质的分子量、分子动力学直径、沸点、密...     

Nitrogen and hydrogen adsorption of activated carbon fibers modified by fluorination

In this study, activated carbon fibers (ACFs) were surface modified with fluorine and mixed oxygen and fluorine gas to investigate the relationship between changes in surface properties by nitrogen and hydrogen adsorption capacity. The changes in surface properties of modified activated carbon fibers were investigated using X-ray photoelectron spectroscopy (XPS) and compared before and after surface treatment. The specific surface area and pore structures were characterized by the nitrogen adsorption isotherm at liquid nitrogen temperature. Hydrogen adsorption isotherms were obtained at 77 K and 1 bar by a volumetric method. The hydrogen adsorption capacity of fluorinated activated carbon fibers was the smallest of all samples. However, the bulk density in this sample was largest. This result could be explained by virial coefficients. The interaction of hydrogen-surface carbon increased with fluorination as the first virial coefficient. Also, the best fit adsorption model was found to explain the adsorption mechanism using a nonlinear curve fit. According to the goodness-of-fit, the Langmuir–Freundlich isotherm model was in good agreement with experimental data from this study.     

酸、碱改性活性炭对甲醇、甲苯吸附性能

分别采用硝酸和氢氧化钠对活性炭进行改性,利用比表面积及孔径分析仪（BET）、扫描电镜（SEM）、Boehm滴定法对活性炭物化性质进行表征,测试改性活性炭对甲醇、甲苯吸附性能。结果表明,经过酸、碱改性后的活性炭比表面积、总孔容、微孔孔容均有所增大。酸改性表面酸性基团增加,碱改性后活性炭酸性基团减少。酸改性后的活性炭对甲醇、甲苯吸附能力有所下降,后经碱改性的活性炭吸附能力均有不同程度的提高。单组分吸附实验时,甲醇穿透曲线斜率要大于甲苯,穿透时间早于甲苯。在多组分吸附过程中会出现甲苯取代甲醇的吸附现象,使得已经被吸附的甲醇发生脱附,此时甲醇的出口浓度大于进口浓度,形成峰值效应。     

沥青基活性碳纤维动态吸附甲苯的性能

以通用级沥青基碳纤维为原料,采用钴盐催化活化法,通过改变活化剂用量和活化时间制备出不同的活性碳纤维。研究了活性碳纤维的动态吸附甲苯以及再生性能。结果表明,活性碳纤维是一种优秀的甲苯吸附材料,其饱和吸附量受比表面积和孔径及其分布的影响。活性碳纤维对甲苯的动态吸附量达到1250 mg/g。20次吸脱附循环再生后,吸附量仍保持在900 mg/g。     

椰壳活性炭对气态氯化汞吸附作用的对比研究

以氯化汞为目标污染物,研究了椰壳活性炭对气态氯化汞的吸附性能,并结合活性炭微结构表征以及动力学模型拟合研究了其吸附机理。结果表明,椰壳活性炭对气态氯化汞的最大吸附量35.9 mg/g,且活性炭比表面积和总孔容对其吸附氯化汞有显著影响,比表面积大、总孔容大有利于提高饱和吸附量。载气流量不影响活性炭对氯化汞的饱和吸附量,但是影响其吸附时间,增大载气流量能够缩短吸附时间。温度对吸附量和吸附时间均有影响,升高温度能够提高吸附量且缩短吸附时间。通过对吸附过程的动力学模拟,发现活性炭对氯化汞的吸附均符合班厄姆动力学模型,相关系数均大于0.99,活性炭的吸附速率与吸附量随比表面积与总孔容的增大而增大。     

Adsorption of 2,4-dichlorophenoxyacetic acid on activated carbon

The kinetics of adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) as a typical herbicide from aqueous solutions on coconut shell activated carbon was studied without preliminary treatment. The surface structure of the activated carbon, which is responsible for its properties, was characterized. The order of reaction in the process of adsorption was determined. The high adsorption capacity of the coconut shell activated carbon was shown.     

活性炭表面改性及吸附极性气体

活性炭的微结构和表面化学特性对其吸附性能产生显著影响。概述了通过调整活性炭孔隙结构。引入化学基团，改变其酸碱度和极性，提高其吸附极性分子能力的方法，介绍了炭表面化学结构，分析了炭微结构，表面基团和吸附质性质对吸附过程的影响。对近年来活性炭表面的改性在吸附SO2和VOCs的实验研究进行了讨论。     

The role of dispersive and electrostatic interactions in the aqueous phase adsorption of naphthalenesulphonic acids on ozone-treated activated carbons

The adsorption of 1-naphthalenesulphonic (NS), 1,5-naphthalenedisulphonic (NDS) and 1,3,6-naphthalenetrisulphonic (NTS) acids on ozonated activated carbons was assessed. Commercial activated carbon (Filtrasorb 400) was treated with different ozone doses in order to study the effect of ozone treatment on their surface properties, and investigate the behaviour of these carbon samples in the adsorption of the above naphthalenesulphonic acids. Experimental results showed that the adsorption capacity sharply decreased as the number of sulphonic groups in the aromatic ring increased. As the concentration of oxygenated electron-withdrawing groups on the carbon surface increased, a significant reduction in adsorption capacity of aromatic sulphonic compounds was observed. These results indicate that the adsorption process takes place mainly by π-π dispersion interactions between the aromatic ring electrons of the naphthalenesulphonic acids and the basal plane of the activated carbon. Moreover, in all cases, the adsorption capacity of aromatic sulphonic acids decreased as the pH increased. This indicates that electrostatic interactions between the adsorbate and the carbon surface also took place, as a result of the ionisation of oxygenated surface groups on the carbon surface. Nevertheless, the dispersive (non-electrostatic) forces govern these adsorption processes.