Fe/AC非均相Fenton体系降解BPA

采用常规浸渍法制备和超声浸渍法制备活性炭载铁催化剂,作为非均相Fenton反应的催化剂。采用电镜扫描和能谱分析对催化剂的形貌特性进行分析,以双酚A为目标降解物,考察催化剂的降解性能。结果表明,超声浸渍法制备的催化剂,活性组分含量高,在载体表面负载均匀,催化剂性能稳定。催化剂用量为2 g/L,H2O2浓度为0.06 mol/L,p H值为6的条件下,催化降解BPA的效率达90%。     

基于响应曲面法优化生物质污泥活性炭的制备方法

针对传统技术制备污泥活性炭的比表面积不高、吸附值低等不足,通过在污泥中添加核桃壳以改善污泥原料缺陷,研究了活化剂种类、核桃壳加量、活化温度、活化时间、活化剂浓度及浸渍比等影响活性炭吸附能力的制备条件。在优化后的条件下制备出了高吸附性能的生物质污泥复合活性炭。结果表明:选择氯化锌作为活化剂,核桃壳加量20%、活化温度500℃、活化时间60 min、活化剂浓度2.5 mol·L-1、浸渍比1∶2.5为最优化制备条件。制备出的生物质污泥复合活性炭碘吸附值为574.11 mg·g-1,产率为43.93%。     

Fe2+改性活性炭的制备及其对聚酯降解产物的脱色性能分析

针对聚酯降解产物的回收再利用问题,采用Fe~(2+)对活性炭进行浸渍改性,并用于聚酯降解产物的脱色。通过比表面积测定、TG分析对改性前后的活性炭进行了表征;研究了改性时Fe~(2+)浓度、超声时间及煅烧温度对活性炭的孔结构、表面官能团以及吸附性能的影响,并以此为基础,通过响应面实验优化了Fe~(2+)对活性炭的改性工艺。结果表明,在Fe~(2+)浓度为1.224 mol·L~(-1),超声时间为4.93 h,且无煅烧的条件下,改性活性炭对染料的平均脱色率最高,可达93.483 5%,可在2 h内实现对聚酯降解产物的完全脱色,且其吸附容量比未改性活性炭提高了1.8 mg·g~(-1)。对改性前后的活性炭进行吸附热力学与吸附动力学实验,发现二者的吸附特征符合Langmuir吸附等温模型及拟二级动力学模型,其决定系数分别为0.990 5、0.997 1及0.999 3、0.999 7。这说明染料在活性炭上的吸附为均一单层分布,吸附过程中包含化学反应。使用Fe~(2+)对活性炭进行浸渍改性后再对聚酯降解产物进行脱色,不仅能提高活性炭对染料的脱色效率,还能提高对其对染料的吸附容量。     

生物基质活性炭对挥发性有机物的吸附

以咖啡渣和柚子皮生物基质为原料用磷酸活化法制成活性炭,探讨了制备条件对活性炭制备的影响,并研究了其对正丁烷的吸附行为。磷酸活化过程中磷酸的用量为生物基质质量的1.5倍为宜,咖啡渣采用超声干燥法,柚子皮采用水热法制备。制备的活性炭对正丁烷均有较好的吸附能力,以柚子皮为原料、磷酸用量为原料质量两倍活化制成的活性炭吸附性能最佳,最大吸附量约为商用活性炭的2倍。吸附剂均能较好地与兰格缪尔曲线相拟合,计算了不同正丁烷覆盖度下的等量吸附热,其变化规律与吸附曲线变化规律相一致。     

废棉布制备活性炭影响因素与机理研究

研究了采用磷酸活化法制备废棉布活性炭的工艺条件。研究表明,废棉布活性炭吸附能力随着磷酸浓度、浸渍时间、活化温度和活化时间的增加呈现先增加后减小的趋势。最佳制备条件为:磷酸浓度40%,浸渍时间24 h,活化温度500℃,活化时间30 min。此时制备的废棉布活性炭性能优于商品活性炭。另外,通过对最佳浓度磷酸浸渍的废棉布进行热失重分析,对磷酸活化废棉布制备活性炭机理开展了初步研究,研究表明磷酸活化废棉布制备活性炭过程分为水分蒸发阶段、炭化阶段、过渡阶段、活化阶段和煅烧阶段。     

KMnO4改性活性炭对臭气中甲硫醇的吸附特性

针对普通活性炭对污水厂臭气中甲硫醇吸附量低的问题,采用KMnO4浸渍改性以获得高甲硫醇吸附量的改性活性炭,通过低温氮吸附仪、扫描电子显微镜和Boehm滴定等表征揭示改性后活性炭吸附量提高的原因,并进行改性活性炭吸附甲硫醇的动力学和热力学研究。结果表明:在KMnO_4浓度为1%、温度为25℃、活性炭与浸渍液质量比为8∶100的条件下浸渍6 h,改性活性炭对甲硫醇的静态吸附量最高,达到344.22 mg·g~(-1),是未改性前的4.04倍:改性活性炭对甲硫醇吸附量提高的原因主要是表面碱性基团的增加(是原来的2.53倍),以及微孔容积和比表面积的增加。改性活性炭对甲硫醇的吸附符合准二级动力学模型,同时粒子内扩散模型显示吸附过程由气相扩散和内扩散共同作用;符合Freundlich吸附等温方程,具有多层吸附特征,且吸附容易进行,属于优惠吸附,是一个自发、放热和熵减的过程,升温不利于对甲硫醇的吸附。     

棉秆基活性炭的制备及其对2,4-二硝基苯酚的吸附

以棉秆为原料,以KOH为活化剂,制备了高比表面棉秆基生物质活性炭。分析了制得的活性炭的元素组成、表面官能团、吸附能力等物化性能,探讨了浸渍比,活化温度,活化时间等工艺参数对制备活性炭得率、表面官能团、碘值、亚甲基蓝值等性能的影响,并通过静态吸附实验比较了不同条件下制备活性炭对2,4-二硝基苯酚的吸附性能,探讨了典型炭样品对2,4-二硝基苯酚的等温吸附特性。结果表明,KOH活化棉秆基生物质活性炭的表面物化性质随浸渍比、活化温度等工艺参数变化而变化,活化适宜条件为浸渍比1：3、活化温度800℃、活化时间90 min,在此条件下制得的炭样的碘值为1 251 mg/g,亚甲基蓝吸附值为478 mg/g,分别是国家一级品标准的1.25倍与3.54倍;对2,4-二硝基苯酚的Langmuir最大吸附量为747 mg/g,与Freundlich模型相比,Langmuir模型能较好地描述2,4-二硝基苯酚在炭样上的吸附行为,表明制备活性炭样品表面吸附位的能量分布较为均一。     

Mn改性活性炭吸附VOCs性能

采用浸渍焙烧法对活性炭进行负载锰(Mn)改性,考察改性活性炭对甲苯、乙酸乙酯及甲苯-乙酸乙酯二元混合气体的吸附性能.研究表明,活性炭浸渍于1.0％高锰酸钾溶液改性后的吸附性能最好.对于单组分VOCs气体,改性后活性炭对甲苯和乙酸乙酯的吸附量较未改性前分别提高了12.7％和16.3％;对于二元混合VOCs气体,改性后活性炭对甲苯及乙酸乙酯的吸附量分别提高了13.1％和22.9％.BET、SEM、FTIR等分析表明,Mn改性活性炭比表面积变大和总孔容增加是改性后吸附量提高的主要原因.     

超声前处理强化活性炭吸附活性艳红X-3B染料废水

探究了超声前处理活性艳红X-3B染料废水强化活性炭吸附降解性能及不同超声参数的影响规律,包括超声功率和超声时间。研究结果表明,超声前处理活性艳红X-3B染料废水可通过空化效应使有机大分子裂解为小分子易于被活性炭吸附,同时可强化其到活性炭微孔中传输,提高了活性炭吸附降解性能,最佳超声功率为320 W。浓度越高,所需超声时间越长,当超声达到一定时间后,继续超声不会影响染料分子的吸附。超声前处理虽然不会改变吸附平衡时间,但可有效增加活性炭处理活性艳红X-3B染料废水的饱和吸附量。     

活性炭纤维及其在水处理中的应用

介绍了活性炭纤维材料的发展历史、类别、结构性能、制备过程。活性炭纤维比普通活性炭性能优越，吸附量大，机械强度高，吸附、脱附速度快，正逐渐地被用于废水处理和饮用水的净化。其具体方法有常用的吸附法、电解法，以及尚在起步阶段的生物活性炭纤维法。     

Utilization of agricultural waste corn cob for the preparation of carbon adsorbent

In the present study, a series of activated carbons were prepared from agricultural waste corn cob by chemical and physical activations with potassium hydroxide (KOH)/potassium carbonate (K2CO3) and carbon dioxide (CO2). The effect of process variables such as impregnation ratio, impregnation time, activation temperature and soaking time of CO2 was studied in order to relate these preparation parameters with the physical properties of final carbon products. The resulting activated carbons were characterized by nitrogen adsorption-desorption isotherms at 77 K. The surface areas and pore volumes of carbons were estimated by the BET equation, the Langmuir equation and the t-plot method. Under the experimental conditions investigated, the main parameters in the activation of corn cob were found to be the impregnation ratio and activation temperature. The soaking time of CO2 is another important variable, which had a strong effect on the pore volume development. The BET surface area and total pore volume were as large as about 2000 m2/g and about 1.0 cm3/g, respectively. This study showed that the activation of agricultural waste corn cob with KOH/K2CO3 and CO2 was suitable for the preparation of large-surface-area activated carbons.     

Preparation of activated carbon using low temperature carbonisation and physical activation of high ash raw bagasse for acid dye adsorption

Activated carbons were prepared from bagasse through a low temperature (160 degrees C) chemical carbonisation treatment and gasification with carbon dioxide at 900 degrees C. The merit of low temperature chemical carbonisation in preparing chars for activation was assessed by comparing the physical and chemical properties of activated carbons developed by this technique to conventional methods involving the use of thermal and vacuum pyrolysis of bagasse. In addition, the adsorption properties (acid blue dye) of these bagasse activated carbons were also compared with a commercial activated carbon. The results suggest that despite the high ash content of the precursor, high surface areas (614-1433 m2 g(-1)) and microporous (median pore size from 0.45 to 1.2 nm) activated carbons can be generated through chemical carbonisation and gasification. The micropore area of the activated carbon developed from chars prepared by the low temperature chemical carbonisation provides favourable adsorption sites to acid blue dye (391 mg g(-1) of carbon). The alkalinity of the carbon surface and total surface area were shown to have complementary effects in promoting the adsorption of acid blue dye. Adsorption of the anionic coloured component of the acid dye was shown to be promoted in carbon exhibiting alkaline or positively charged surfaces. This study demonstrates that activated carbons with high acid dye adsorption capacities can be prepared from high ash bagasse based on low temperature chemical carbonisation and gasification.     

磷酸微波活化多孔生物质炭对亚甲基蓝的吸附特性

以甘蔗渣为原料,采用微波辅助H3PO4活化法制备富含含氧酸官能团的中孔生物质炭。通过扫描电子显微镜SEM、傅立叶变换红外光谱FT-IR等技术对生物质炭物理化学性质进行表征,并通过静态实验法,探讨炭样对亚甲基蓝的吸附行为及热力学性质。结果表明,H3PO4活化制备蔗渣生物质炭的适宜条件为浸渍比1：1,烘干时间10h,活化功率900W,活化时间22min,在此条件下制得的生物质炭得率为39．2％,碘值为817mg／g,亚甲基蓝值为229mg／g,为国家一级品标准的1．7倍。红外光谱分析表明,炭样表面以羟基、羰基、羧基等酸性官能团为主。静态吸附实验表明,Freundlich方程与Redlich—Peterson方程能较好地描述等温吸附行为,表现为优惠吸附。热力学研究表明,吸附吉布斯自由能（△G0）〈0,说明吸附反应是自发过程,而吸附标准焓变（△H0）〉70KJ／mol,表明亚甲基蓝在制备炭样上的吸附是吸热反应,升温有利于吸附,且化学反应在吸附过程中发挥了重要作用。     

UTILIZATION OF AGRICULTURAL WASTE CORN COB FOR THE PREPARATION OF CARBON ADSORBENT

In the present study, a series of activated carbons were prepared from agricultural waste corn cob by chemical and physical activations with potassium hydroxide (KOH)/potassium carbonate (K₂CO₃) and carbon dioxide (CO₂). The effect of process variables such as impregnation ratio, impregnation time, activation temperature and soaking time of CO₂ was studied in order to relate these preparation parameters with the physical properties of final carbon products. The resulting activated carbons were characterized by nitrogen adsorption[ch-[chdesorption isotherms at 77 K. The surface areas and pore volumes of carbons were estimated by the BET equation, the Langmuir equation and the t-plot method. Under the experimental conditions investigated, the main parameters in the activation of corn cob were found to be the impregnation ratio and activation temperature. The soaking time of CO₂ is another important variable, which had a strong effect on the pore volume development. The BET surface area and total pore volume were as large as about 2000 m²/g and about 1.0 cm³/g, respectively. This study showed that the activation of agricultural waste corn cob with KOH/K₂CO₃ and CO₂ was suitable for the preparation of large-surface-area activated carbons.     

Preparation and characterization of activated carbons from tobacco stem by chemical activation

Activated carbons were prepared from tobacco stem by chemical activation using potassium hydroxide (KOH), potassium carbonate (K₂CO₃), and zinc chloride (ZnCl₂). The effects of the impregnation ratio (activating agent/precursor) and activating agents on the physical and chemical properties of activated carbons were investigated. The textual structure and surface properties of activated carbons were characterized by nitrogen (N₂) adsorption isotherm, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), x-ray photoelectron spectroscopy (XPS), and thermogravimetry (TG). ZnCl₂, acting as a superior activating agent compared to the others, produced much more porosity. The maximum specific surface area reached 1347 m²/g, obtained by ZnCl₂ activation with an impregnation ratio of 4.0. Moreover, ZnCl₂ activation yielded products with an excellent thermostability, attributed to different activation mechanisms. Various oxygen functions were detected on the activated carbon surface, and hydroxyl and ester groups were found to be in the majority.

Implications: Tobacco stem, the residue from cigarette manufacturing, is usually discarded as waste, leading to serious resource waste and environmental problems. This study provides an effective utilization available for this solid residue by using it as the starting material in the preparation of activated carbon with chemical activation. Activated carbons with high specific area and various surface functions have been prepared, and the effects of the amount and type of activating agents on the physical and chemical properties of activated carbon were investigated as well.     

Characterization of activated carbons prepared from sugarcane bagasse by ZnCl2 activation.

Activated carbons were prepared from the agricultural waste of sugarcane bagasse by the chemical activation with zinc chloride (ZnCl2) at the activation temperature of 500 degrees C with soaking time of 0.5 hour. The influence of activation parameters on the final carbon products was examined by varying the impregnation ratio (i.e., mass ratio of added ZnCl2 to bagasse) and bagasse size. The physical properties of carbon products were characterized by nitrogen adsorption/desorption isotherms (at 77 K) and helium displacement method. The surface area and pore volume of carbons were thus obtained by the BET equation and t-plot method. Also, the particle density and porosity of carbons were estimated by the total pore volume and true density. The increases of the values of surface area and pore volume are approximately proportional to the impregnation ratio. The microporous carbon product with the BET surface area of 905 m2/g and total pore volume of 0.44 cm3/g was obtained in the present study. Further, the adsorption isotherms of two acid dyes from aqueous solutions onto the carbon products were performed at 30 degrees C. The results show that the adsorption isotherms of acid dyes with high molecular weight or large molecular size on the microporous adsorbents of activated carbons are plateau forms, indicating multilayer adsorptions, which may be attributed to the steric hindrance of the adsorbate molecules.     

超声辐射浸渍法制备Fe-Ni-Mn/Al2O3催化剂及性能研究

以Al2O3为载体,分别采用超声辐射浸渍法和普通浸渍方法制备Fe-Ni-Mn/Al2O3催化剂。采用BET、XRD和SEM对催化剂的理化性质和孔结构进行了分析,以模拟酸性绿B废水为研究对象考察催化剂的催化性能。实验结果表明,浸渍溶液pH值和焙烧温度显著影响催化剂的性能。与普通浸渍法相比,超声浸渍法制备的Fe-Ni-Mn/Al2O3催化剂对酸性绿B脱色反应表现出较高的催化活性。     

超声辐射浸渍法制备Fe-Ni-Mn/Al_2O_3催化剂及性能研究

以Al2O3为载体,分别采用超声辐射浸渍法和普通浸渍方法制备Fe-Ni-Mn/Al2O3催化剂。采用BET、XRD和SEM对催化剂的理化性质和孔结构进行了分析,以模拟酸性绿B废水为研究对象考察催化剂的催化性能。实验结果表明,浸渍溶液pH值和焙烧温度显著影响催化剂的性能。与普通浸渍法相比,超声浸渍法制备的Fe-Ni-Mn/Al2O3催化剂对酸性绿B脱色反应表现出较高的催化活性。     

Roles of physical and chemical properties of activated carbon in the adsorption of lead ions

Elucidation of the roles of chemical and physical properties of activated carbons is an important basis for the systematic development of adsorbents with optimal properties specific for certain applications. Such an understanding has challenged most researchers and this has been attributed with the difficulty in decoupling the effect of chemical and physical properties that characterize activated carbons. This study proposed empirical modeling in resolving the effects of individual carbon properties in lead adsorption. A model based on lead adsorption and carbon properties including total surface area, mean pore size and heteroatom concentrations has been shown to adequately describe the lead adsorption onto activated carbons prepared from bagasse. To support this investigation a series of activated carbons were prepared from bagasse by physical and by chemical activation techniques. The surface chemical properties of the carbons were inferred from carbon pH and heteroatom concentrations. The physical characterizations of the carbons included total surface area by the BET technique and mean pore size measured using the Horvath-Kawazoe equation. Adsorption tests were conducted using a low concentration of lead (5 ppm) and the solution pH was maintained at 1.0 to maintain lead speciation to the un-complexed Pb(2+) ion. The adequacy of the proposed empirical models was statistically assessed. This form of analysis was shown to provide valuable information in tailor making adsorbents and selecting appropriate adsorbents for lead adsorption.     

The degradation of chlorpyrifos and diazinon in aqueous solution by ultrasonic irradiation: effect of parameters and degradation pathway

In this paper, elimination of two types of organophosphorus pesticides (OPPs), chlorpyrifos and diazinon spiked in aqueous solution by ultrasonic irradiation was investigated. Results showed that chlorpyrifos and diazinon could be effectively and rapidly degraded by ultrasonic irradiation, and the degradation of both pesticides was strongly influenced by ultrasonic power, temperature and pH value. Furthermore, two and seven products for the degradation of chlorpyrifos and diazinon formed during ultrasonic irradiation have been identified by gas chromatography-mass spectrometry, respectively. The hydrolysis, oxidation, hydroxylation, dehydration and decarboxylation were deduced to contribute to the degradation reaction and the degradation pathway for each pesticide under ultrasonic irradiation was proposed. Finally, the toxicity evaluation indicated that the toxicity decreased for diazinon solution after ultrasonic irradiation, but it increased for chlorpyrifos solution. The detoxification of OPPs by ultrasonic irradiation was discriminative.