三醋酸甘油酯在活性炭上的吸附特性

三醋酸甘油酯在卷烟中主要作为醋酸纤维过滤嘴的增塑剂使用。在不同的温度和相对湿度条件下,研究活性炭对三醋酸甘油酯的吸附机理,探讨了活性炭的孔结构对其吸附性能的影响。结果表明:活性炭吸附三醋酸甘油酯符合Langmuir模型,其饱和吸附量为333 mg/g;高温有利于吸附三醋酸甘油酯,而增加湿度则抑制了三醋酸甘油酯的吸附;在一定范围内,当活性炭孔面积大于三醋酸甘油酯最小截面积的2.8倍时,活性炭对三醋酸甘油酯的吸附量增多,反之减少。因此,较大的微孔孔径有利于活性炭吸附三醋酸甘油酯。     

酸碱改性活性炭及其对甲苯吸附的影响

分别用酸溶液(H_2SO_4、HNO_3、H_3PO_4)和碱溶液(NaOH或NH_3·H_2O)浸渍方法对活性炭进行改性,并对酸改性活性炭进行碱溶液二次改性处理,通过表征改性前后活性炭BET比表面积、孔结构、表面官能团等理化特征和测定其对甲苯蒸气的饱和吸附量,研究了影响活性炭吸附甲苯蒸气的关键因素.结果表明,酸改性使BET比表面积、微孔面积、微孔容积减少、表面酸性官能团增加,而碱改性呈现相反的理化特征变化.活性炭理化特征的变化可能与改性溶液的酸碱性、氧化还原性有关,并且这种相反的变化直接关系到活性炭对甲苯蒸气的吸附.3种酸改性的活性炭对甲苯蒸气饱和吸附量相对于原活性炭减少9.6%~20.0%,而两种碱改性的活性炭则增加29.2%~39.2%.相关性分析显示甲苯吸附量与BET比表面积、微孔面积、微孔容积正相关,而与表面酸性官能团负相关;多元回归分析进一步表明微孔容积和酸性官能团数量是影响活性炭甲苯吸附的关键因素.二次改性活性炭甲苯吸附量与表面含氧酸性官能团拟合结果则表明,—COOH、C＝O和—OH都对活性炭甲苯吸附能力有影响,其中—COOH影响较大.研究结果表明有效提高活性炭对甲苯吸附能力,改性宜以提高活性炭微孔容积和减小活性炭表面酸性官能团数量,特别是—COOH数量为目标导向.     

活性炭在煤气化废水处理中的应用

活性炭由于自身的大孔、中孔和微孔结构特别是其比表面积大等特点对去除一部分难降解的有机物和某些无机物有一定的作用.本文介绍了活性炭在煤气化废水处理中的应用,指出了其工艺特点,阐述了它的诸多优点,并预测了其广阔的应用前景.     

超滤处理东江水不可逆膜污染物的识别和活性炭对其吸附去除

利用超滤实验以及6种粉末活性炭吸附东江水有机物的水质数据,通过三维荧光光谱-平行因子分析(EEMPARAFAC),考察东江水中造成不可逆膜污染的主要组分和活性炭吸附这些组分的效果;随后进行活性炭对不可逆膜污染组分吸附效果与对应活性炭孔结构参数的相关性分析,揭示活性炭的表面物理性质对不可逆膜污染物吸附的影响.EEMPARAFAC模型识别出东江水含有2个类腐殖质荧光组分C1和C3,以及1个类蛋白质(类色氨酸)荧光组分C2,其中C2为主要不可逆膜污染物.同时,所有活性炭对3种荧光组分均有较好的吸附效果,其中对主要膜污染物C2的去除率可达54.0%~74.6%.相关性分析发现,活性炭对主要膜污染荧光组分C2吸附效果受活性炭微孔表面积的影响,而活性炭对两种次要膜污染荧光组分C1和C3吸附效果受活性炭中大孔表面积和BET比表面积影响.实验结果可为活性炭-超滤工艺处理东江水的活性炭选型提供技术指导.     

水处理活性炭吸附性能指标的表征与应用

使用碘值、苯酚值、甲基蓝值和丹宁酸值4种吸附容量性能指标组成水处理活性炭选型技术.经BET测试验证,碘值可以体现活性炭中孔径略大于1.0nm微孔的发达程度,表征比表面积大小;甲基蓝值则代表孔径大于1.5nm的微孔和中孔发达程度;而丹宁酸值代表直径大于2.8nm左右的中孔数量;苯酚值体现活性炭表面化学信息,可表征活性炭对于小分子芳环类和极性有机物的吸附能力.硝基苯、甲基叔丁基醚(MTBE)、双酚A(BPA)、腐殖酸以及焦化厂二级生化出水的吸附实验结果均验证了该技术作为水处理活性炭实用选型方法的有效性.     

活性炭孔结构和表面化学性质对吸附硝基苯的影响

通过对活性炭HNO3氧化及随后的N2:气氛中热处理,研究了活性炭性质对其吸附硝基苯性能的影响.以低温液氮(N2/77K)吸附测定活性炭的比表面积和孔容、孔径分布,以SEM观测活性炭表面形貌,以Boehm滴定、FTIR、零电荷点pHpzc测定及元素分析定量表征活性炭表面含氧官能团变化.结果表明, HNO3氧化可以显著改变活性炭表面化学性质,增加活性炭表面酸性含氧官能团数量,对活性炭孔隙结构影响不大.随后N2:气氛中热处理可以造成活性炭表面酸性含氧官能团分解,外表面积增大,微孔烧蚀为中孔.硝基苯在活性炭上的吸附基本符合Langmuir方程,改性后活性炭对硝基苯的吸附容量明显改变, ACNO-T、ACraw、ACNO吸附容量分别为1011.31、483.09、321.54 mg·g-1.较大的外表面积、适宜数量的中孔以及较少的酸性含氧官能团是ACNO-T对硝基苯表现出较高吸附容量的主要原因.     

改性活性炭吸附烟气中二氧化硫气体实验研究

活性炭材料因具有丰富的孔结构和较大的比表面积,被广泛用于大气污染物的治理.将活性炭用多种方法进行改性处理,与未经改性处理的活性炭进行比较,发现改性后的活性炭对烟气中SO2气体的吸附效果比原始活性炭的吸附效果好.     

活性炭吸附水中金属离子和有机物吸附模式和机理的研究

活性炭被用于处理水中多种痕量重金属离子和微量有机物。但在一定的条件下活性炭对一些污染物的吸附去除率很低,为了更好的理解和预测活性炭对水中微污染物的吸附行为,本文对活性炭吸附模式和机理方面的研究进行了综述。活性炭比表面积大,微孔结构丰富,其表面含有丰富的含氧官能团（羧基,酚羟基、羰基、内酯基）活性炭对污染物质的吸附受吸附剂的性质、吸附质的性质和溶液性质等因素的影响。对于金属离子Langmuir和Freundlich模式是活性炭吸附重金属离子的经典经验模式,但表面络合模式能更好的描述变化条件下的吸附现象。活性炭吸附金属离子的主要作用是静电作用和离子交换作用。对于有机物稀溶液条件下的吸附多符舍Freundlich模式。给一受电子作用、扩散作用、静电作用是主要的作用机制。pH对金属离子和有机物的吸附有重要的影响,腐植酸对金属离子有吸附竞争作用。     

富含中孔与酸性基团的生物质炭的制备与吸附性能

以棉秆基生物质纤维为原料,采用磷酸一步活化法制备了同时富含中孔与含氧酸官能团的新型高比表面棉秆纤维基生物质活性炭,分析了浸渍比、炭化温度及保温时间等操作参数对活性炭纤维组成、得率、孔结构及表面官能团含量的影响,测定了制得的棉秆纤维基活性炭对水中对Pb(Ⅱ)与对硝基苯胺的等温吸附性能,并初步探讨了其吸附机制.结果表明,棉秆纤维基生物质炭孔结构与含氧酸基团因制备条件不同有较大变化,实验条件下制备的棉秆基活性炭纤维产率、中孔孔容与比表面的最大值分别为35.5%、0.91 cm3·g-1、1731 m2·g-1;在3∶2的浸渍比,600℃活化90 min的工艺条件下,制备的样品ACF-01的总孔孔容达1.02 cm3·g-1,比表面积为1 731 m2·g-1,微、中孔比例分别为66%与31%,中孔集中在5 nm以内,富含含氧酸官能团.样品ACF-01对水中Pb(Ⅱ)与对硝基苯胺的Langmuir最大吸附量分别为123 mg·g-1和427 mg·g-1,吸附性能远高于微孔孔容相近的商业活性炭纤维ACF-CK,这表明活性炭ACF-01的中孔和含氧酸官能团在吸附过程中发挥了重要作用.     

活性炭吸附有机蒸气性能的研究

吸附法在油气回收技术中运用很广泛.吸附剂的选择对吸附分离效果起到了决定性作用.选用3种商用活性炭,以正己烷和正庚烷为吸附质,在温度为293.15 K下进行了静态和动态吸附实验,并研究了活性炭孔结构对其吸附性能和吸附能的影响,同时利用Logistic模型的回归公式对活性炭的吸附穿透曲线进行拟合.结果表明,活性炭的比表面积和孔容是其吸附性能主要影响因素;正己烷和正庚烷的吸附行均符合Langmuir吸附等温模型;3种活性炭对正己烷和正庚烷的吸附能都随其比表面积变大而变大;Logistic模型拟合曲线与实验结果具有高度相似性,可用于活性炭吸附穿透曲线的预测.     

废茶活性炭脱硫脱硝性能的应用研究

为探讨废茶活性炭对于SO2和NO脱除作用的制约因素,分别考察了材料孔径结构、石墨化程度及表面结构对其脱硫脱硝性能的影响,同时研究了其吸附机制及动力学过程.结果表明,较高的石墨化程度是影响材料脱硫性能的主要因素,微孔径较小且含氮碱性基团较高时有利于SO2的脱除;发达的中孔结构是制约NO脱除效率的关键因素,含氮碱性基团对NO的脱除具有一定的促进作用;烟气中SO2和NO共存时,材料的脱硫脱硝性能均有所降低,氧气和水蒸气的加入能够改善其脱硫脱硝效率;废茶活性炭在无水环境下对于SO2和NO的吸附作用均以物理吸附为主,水蒸气的存在促进了材料对SO2的化学吸附;通过动力学模型的拟合发现,Bangham吸附模型能够很好地描述材料脱硫脱硝的动力学过程,其R2均高于0.989,材料对于SO2和NO的吸附速率常数均随氧气和水蒸气的加入而减小.     

Comparison of activated carbon and iron/cerium modified activated carbon to remove methylene blue from wastewater

The methylene blue(MB)removal abilities of raw activated carbon and iron/cerium modified raw activated carbon(Fe–Ce-AC)by adsorption were researched and compared.The characteristics of Fe–Ce-AC were examined by N_2adsorption,zeta potential measurement,FTIR,Raman,XRD,XPS,SEM and EDS.After modification,the following phenomena occurred:The BET surface area,average pore diameter and total pore volume decreased;the degree of graphitization also decreased.Moreover,the presence of Fe_3O_4led to Fe–Ce-AC having magnetic properties,which makes it easy to separate from dye wastewater in an external magnetic field and subsequently recycle.In addition,the equilibrium isotherms and kinetics of MB adsorption on raw activated carbon and Fe–Ce-AC were systematically examined.The equilibrium adsorption data indicated that the adsorption behavior followed the Langmuir isotherm,and the pseudo-second-order model matched the kinetic data well.Compared with raw activated carbon,the maximum monolayer adsorption capacity of Fe–Ce-AC increased by27.31%.According to the experimental results,Fe–Ce-AC can be used as an effective adsorbent for the removal of MB from dye wastewater.     

钙基吸附剂吸附氯化镉的微观形态及机理初探

在生活垃圾焚烧烟气模拟净化试验装置中,采用氯化镉(CdCl2)作为气态重金属发生源,模拟改性钙基吸附剂对重金属的动态吸附能力,并与活性炭进行对比.采用X-射线衍射和SEM-EDX(扫描电子显微镜-X射线能谱分析)方法,对吸附重金属前后的吸附剂样品的微观形态特征进行观察,并且对吸附机理进行研究.结果表明:改性吸附剂存在CaO/NaCI共晶体,具有发达的内孔结构,对气态CdCl2除了具有物理吸附作用以外,还存在化学扩散和吸附作用,且化学吸附是主要作用机制.     

Enhancement of elemental mercury adsorption by silver supported material

Mercury, generally found in natural gas, is extremely hazardous. Although average mercury levels are relatively low, they are further reduced to comply with future mercury regulations, which are stringent in order to avoid releasing to the environment. Herein, vapor mercury adsorption was therefore investigated using two kinds of supports, granular activated carbon (GAC) and titanium dioxide (TiO₂). Both supports were impregnated by silver (5 and 15 wt.%), before testing against a commercial adsorbent (sulfur-impregnated activated carbon, SAC). The adsorption isotherm, kinetics, and its thermodynamics of mercury adsorption were reported. The results revealed that Langmuir isotherm provided a better fit to the experimental data. Pseudo second-order was applicable to describe adsorption kinetics. The higher uniform Ag dispersion was a key factor for the higher mercury uptake. TiO₂ supported silver adsorbent showed higher mercury adsorption than the commercial one by approximately 2 times. Chemisorption of mercury onto silver active sites was confirmed by an amalgam formation found in the spent adsorbents.     

Enhancement of elemental mercury adsorption by silver supported material

Mercury, generally found in natural gas, is extremely hazardous. Although average mercury levels are relatively low, they are further reduced to comply with future mercury regulations, which are stringent in order to avoid releasing to the environment. Herein, vapor mercury adsorption was therefore investigated using two kinds of supports, granular activated carbon (GAC) and titanium dioxide (TiO₂). Both supports were impregnated by silver (5 and 15 wt.%), before testing against a commercial adsorbent (sulfur-impregnated activated carbon, SAC). The adsorption isotherm, kinetics, and its thermodynamics of mercury adsorption were reported. The results revealed that Langmuir isotherm provided a better fit to the experimental data. Pseudo second-order was applicable to describe adsorption kinetics. The higher uniform Ag dispersion was a key factor for the higher mercury uptake. TiO₂ supported silver adsorbent showed higher mercury adsorption than the commercial one by approximately 2 times. Chemisorption of mercury onto silver active sites was confirmed by an amalgam formation found in the spent adsorbents.     

SO_2体积分数对ZL50活性炭吸附脱硫行为的影响和动力学分析

通过动态吸附烟气脱硫实验,考察了烟气中不同SO2体积分数对ZL50脱硫脱硝活性炭脱硫行为的影响,并进行了动力学分析.随着烟气中SO2体积分数增大,脱硫率和ZL50脱硫脱硝活性炭的活性度下降;SO2吸附量和吸附速率增大.模拟结果表明,Bangham模型模拟效果最优,SO2的催化氧化反应对化学吸附有重要影响;Lagergren准一级吸附速率常数随SO2进口体积分数的增加而增大,表明SO2的催化氧化反应在吸附前期可能为速控步骤.推导和定义了Lagergren模型和Bangham模型的初始吸附速率;推导了文献上的Ho模型和Elovich模型的初始速率式。定义的Bangham初始吸附速率与初始吸附速率实验值吻合最好;建立的Bangham吸附反应动力学模型能较好地描述SO2动态吸附速率.结果表明,SO2的初始反应速率分级数为1或接近1,而O2和水蒸气的初始速率分级数分别为0.15～0.20和0.45～0.50之间的常数.     

Regeneration performance and carbon consumption of semi-coke and activated coke for SO2 and NO removal

To decrease the operating cost of flue gas purification technologies based on carbon-based materials, the adsorption and regeneration performance of low-price semi-coke and activated coke were compared for SO₂ and NO removal in a simulated flue gas. The functional groups of the two adsorbents before and after regeneration were characterized by a Fourier transform infrared (FTIR) spectrometer, and were quantitatively assessed using temperature programmed desorption (TPD) coupled with FTIR and acid–base titration. The results show that semi-coke had higher adsorption capacity (16.2% for SO₂ and 38.6% for NO) than activated coke because of its higher content of basic functional groups and lactones. After regeneration, the adsorption performance of semi-coke decreased because the number of active functional groups decreased and the micropores increased. Semi-coke had better regeneration performance than activated coke. Semi-coke had a larger SO₂ recovery of 7.2% and smaller carbon consumption of 12% compared to activated coke. The semi-coke carbon-based adsorbent could be regenerated at lower temperatures to depress the carbon consumption, because the SO₂ recovery was only reduced a small amount.     

混凝-吸附处理黄河水及对氯消毒中氯衰减的影响

选用2种无机高分子混凝剂聚合氯化铁(PFC)和聚合氯化铝(PAC)处理黄河水,考察了混凝剂的投加量对浊度、UV254、DOC和高锰酸盐指数的去除效果,并结合混凝出水的Zeta电位分析其混凝机制.选择粉末活性炭与混凝联用,研究了混凝剂和吸附剂投加量以及二者的投加顺序对有机物去除效果的影响,并对混凝吸附后出水进行加氯消毒,考察水中残余氯随时间的变化.结果表明,2种混凝剂均有较高的浊度去除率(﹥90%).PAC对UV254、高锰酸盐指数和DOC的去除率分别为29.2%、26.1%和27.9%;PFC对三者的去除率分别为32.3%、23.3%和32.9%.PAC在混凝过程中,电中和作用占主导地位;PFC在混凝过程中,吸附架桥和电中和同时发挥作用.混凝-吸附联用处理黄河水样时,有机物的去除率随混凝剂和吸附剂投加量的增加而升高.先混凝后吸附工艺对UV254和DOC的去除效果优于先吸附后混凝工艺.先使用PAC混凝后吸附对UV254和DOC的去除率分别为95.2%和99.9%;对于PFC,先混凝后吸附对UV254和DOC的去除率分别为90.1%和99.9%.但是先投加粉末活性炭能提高矾花的沉降性能,且处理出水在保持持续消毒效果方面优于前者.     

Modification of a magnetic carbon composite for ciprofloxacin adsorption

A magnetic carbon composite, Fe₃O₄/C composite, was fabricated by one-step hydrothermal synthesis, modified by heat treatment under an inert atmosphere (N₂), and then used as an adsorbent for ciprofloxacin (CIP) removal. Conditions for the modification were optimized according to the rate of CIP removal. The adsorbent was characterized by Fourier transform infrared spectroscopy, X-ray diffraction measurements, vibrating-sample magnetometry, scanning electron microscopy, transmission electron microscopy, and N₂ adsorption/desorption isotherm measurements. The results indicate that the modified adsorbent has substantial magnetism and has a large specific area, which favor CIP adsorption. The effects of solution pH, adsorbent dose, contact time, initial CIP concentration, ion strength, humic acid and solution temperature on CIP removal were also studied. Our results show that all of the above factors influence CIP removal. The Langmuir adsorption isotherm fits the adsorption process well, with the pseudo second-order model describing the adsorption kinetics accurately. The thermodynamic parameters indicate that adsorption is mainly physical adsorption. Recycling experiments revealed that the behavior of adsorbent is maintained after recycling for five times. Overall, the modified magnetic carbon composite is an efficient adsorbent for wastewater treatment.     

碱改性活性炭表面特征及其吸附甲烷的研究

采用不同浓度的氢氧化钠对椰壳活性炭进行表面改性.BET和SEM分析改性前后活性炭的表面结构,Boehm滴定和SEM/EDS方法测定活性炭表面元素及含氧基团.研究改性活性炭对甲烷的吸附性能和吸附行为.结果表明,经氢氧化钠改性处理后,活性炭孔径变化不明显,表面含氧基团显著减少;当氢氧化钠的浓度>3.3 mol·L-1时,活性炭的比表面积和孔容大于未处理的活性炭,并且随碱的浓度增加而增大.与改性前的活性炭相比,甲烷在碱改性活性炭上的吸附量提高了24%.增加活性炭的比表面积和孔容,减少表面的含氧基团有利于甲烷的吸附.甲烷的吸附行为符合Langmuir等温吸附式,吸附常数为163.7 m3·mg-1.