热处理ZSM-5制备微孔-介孔双孔分子筛

对商品化ZSM-5分子筛进行热处理制得了微孔-介孔双孔分子筛,微孔和介孔的结构特征由热处理工艺决定.其中在1000℃的空气中热处理2h的样品,介孔部分对比表面积的贡献已接近微孔部分对比表面积的贡献.这种双孔分子筛有很窄的介孔孔分布和较高的结晶度.     

椰壳纤维基高比表面积中孔活性炭的制备

以椰壳纤维为原料,制备高比表面积中孔活性炭.采用正交试验设计实验方案,研究KOH和NaOH复合活化法制备活性炭的实验方案与工艺条件.考察了活化剂配比、炭化温度、活化温度、时间和升温速率对所制活性炭吸附性能的影响.在最佳工艺条件下,所制活性炭的比表面积达到2032m2/g,中孔发达,特别是2nm～4nm的,中孔比例达到28%.活性炭对的碘吸附值为1435mg/g,亚甲基蓝吸附值为495mg/g,产率为49%.     

微波加热碳酸钾法制备烟杆基高比表面积活性炭

以烟杆炭化料为原料,采用微波加热碳酸钾活化法制备了高比表面积活性炭.研究了微波加热时间和碱炭比对活性炭的得率和吸附性能的影响,得到了优化工艺条件,所得活性炭产品的碘吸附值为1834mg/g,亚甲基兰吸附值为517.5mg/g,得率为16.65%.产品的吸附性能超过了双电层电容器专用活性炭(LY/T 1617-2004)标准的要求,同常规加热相比,活化时间缩短了78.26% .同时测定了该活性炭的氮吸附等温线,通过非定域化密度函数理论表征了活性炭的孔结构.该高比表面积活性炭的比表面积为2557m2/g,总孔体积为1.6470ml/g.     

高比表面积聚苯乙烯基球状活性炭的制备研究

以聚苯乙烯基大孔吸附树脂球为炭前驱体,经空气预氧化、炭化和活化制备了高比表面积球状活性炭.系统考察了不同氧化和活化条件对氧化球和活化球的物理性能的影响.结果表明:升温速率、氧化温度和氧化时间分别为0.25℃/min、300℃和3h时所得到的氧化球的CCl4吸附值最高,可达970mg/g.此外,当活化温度和活化时间分别为850℃和4h时,球状活性炭的CCl4吸附值最高,为2700mg/g,相应的比表面积为1759m2/g.     

高比表面积聚丙烯腈基球状活性炭的制备研究

以自制的聚丙烯腈(PAN)基球为炭前驱体,经空气预氧化、炭化和活化处理制备了高比表面积的球状活性炭。着重考察了温度对PAN球状活性炭制备过程中预氧化、炭化和活化的影响。借助红外光谱(IR)、热重分析(TG)、差热分析(DTA)、扫描电镜(SEM)、比表面积(BET)分析仪等表征手段,对不同温度条件下的PAN球状活性炭的结构变化、转变机理进行了探讨。结果表明:预氧化温度和活化温度分别以300℃和800℃为最佳,相应的比表面积可达1190m2 g-1。     

多级孔材料研究进展

多孔材料具有孔隙率高、比表面积大、导热系数低、体积密度小及化学性质稳定等优点,在吸附与分离、催化剂载体、隔热材料、能量储存、传感器等领域拥有广阔的应用前景。基于孔直径的大小可将多孔材料分为三类:孔径大于50nm的大孔材料(Macroporous materials),孔径介于2～50nm的介孔材料(Mesoporous materials)和孔径小于2nm的微孔材料(Microporous materials)。但是,由于孔径的限制,这三类材料的应用均存在一定的局限性。多级孔材料兼具通透性好、孔隙结构发达、体积密度小、比表面积和孔体积大等优点,打破了传统单级孔材料孔结构单一的局限,因此越来越受到研究人员的关注。然而,多级孔材料在制备中仍存在较多问题。例如,其合成过程通常会涉及到两种及两种以上的方法,制备工艺复杂;现有的多级孔材料的制备成本高,孔结构难以控制。因此,研究者们主要从优化多级孔材料的制备工艺以及降低生产成本等方面入手,制备出孔径均一且可控的多级孔材料。多级孔材料主要有大孔-介孔材料(Macro-mesoporous materials)、微孔-介孔材料(Micro-mesoporous materials)以及含有两种或多种不同孔径的介孔-介孔材料(Meso-mesoporous materials)。大孔-介孔材料常见的制备方法有模板法、发泡法、溶胶-凝胶法及熔盐法等;微孔-介孔材料的主要制备方法有化学活化法、模板法和水热法等;介孔-介孔材料的制备方法主要有水热法、模板法、溶胶-凝胶法及自组装法等。本文综述了近年来多级孔材料的最新研究进展,分别对大孔-介孔、微孔-介孔及介孔-介孔材料的制备方法进行了介绍,并简要分析了未来本领域研究的发展趋势。     

CO2活化-碱液沸煮制备高介孔率的稻壳活性炭

以CO2活化-碱液沸煮新工艺制备高介孔率的稻壳活性炭,即先以CO2活化,后用NaOH溶液沸煮;采用正交试验研究CO2流量、CO2活化时间、NaOH浓度、NaOH沸煮时间、液固比对活性炭碘值的影响,并优化制备条件;采用N2吸脱附法表征活性炭;探讨孔隙发展机理。结果表明:采用CO2活化-碱液沸煮工艺,可以在无机碱不必经历高温过程的情况下制得介孔率高达79%的稻壳活性炭,其比表面积、孔容积、产率分别达到899m2/g、0.783 cm3/g、26.2%。     

马尾藻基高比表面积活性炭的制备及表征

以马尾藻为原料,采用KOH活化法制备高比表面积活性炭。探索制备马尾藻基活性炭的实验方案和最佳工艺条件。采用正交实验法研究了炭化温度、炭化时间、低温活化温度、低温活化时间和浸渍时间对制得活性炭比表面积和孔容的影响。采用N_2吸附、SEM表征考察了活性炭的孔隙结构和表面形貌。通过正交实验法分析发现,制备马尾藻基高比表面积活性炭的最佳工艺条件为:炭化温度600℃,炭化时间180min,低温活化温度400℃,低温活化时间45min,浸渍时间2h。在16组实验条件下,制备的活性炭比表面积最大为3 122m2/g,所有样品的孔径几乎全部分布在6nm以内。     

介孔泡沫及手性介孔材料的制备与应用

介孔泡沫材料具有超大介孔、开放式孔结构、孔径可调等特点,在催化剂载体、酶固定等领域具有明显的优势.手性介孔材料除了具有常规介孔材料的特点外还具有手性,因此在立体化学领域具有潜在的研究与应用价值.综述了介孔泡沫材料以及手性介孔材料的合成与应用.     

溶胶-凝胶法制备的纳米介孔材料研究进展

纳米介孔材料具有大的比表面积和孔体积、均一可调的孔道结构,已经被广泛应用在酶的固定吸附、生物催化、免疫亲和色谱、药物控释放和生物物理研究模型等方面。综述了溶胶-凝胶法制备的纳米介孔材料的最近研究进展,介绍了纳米介孔材料的种类和溶胶-凝胶制备方法,详细阐述了纳米介孔材料在固定生物活性蛋白方面的研究,并展望了纳米介孔材料在生物领域的应用。     

Preparation of a pitch-based activated carbon with a high specific surface area

Pitch based activated carbons (PAC) with a high specific surface area were produced by a direct chemical activation route in which oxidative stabilized pitch derived from ethylene tar oil was reacted with potassium hydroxide under various activation conditions. It was found that PACs with a surface area of around 2600–3600 m² g^-1 could be obtained under suitable activation conditions. N₂ adsorption (at 77 K) and X-ray photoelectron spectroscopy experiments showed that the PAC has a uniformly developed micropore structure and a narrow pore size distribution (radius 0.8–1.6 nm). Abundant oxygen-containing functional groups (such as C–OH, C–O–C, C=O, COOR etc.) were found to exist on its surface. Compared with a commercially available activated carbon (AC) and also a pitch based activated carbon fibre, PAC has a quicker adsorption–desorption velocity and a larger adsorptive capacity to benzene due to its higher surface area. Clear surface differences between PAC and AC were observed by transmission electron microscopy. This revised version was published online in November 2006 with corrections to the Cover Date.     

Preparation and application of porous activated carbon using phenolic distillation residue

Journal of Materials Science - Porous carbons (PCs) have been prepared by using the heavy fraction of phenolic distillation residue as raw materials, and it used a carbonize-activated one-step...     

KOH活化法高比表面积竹质活性炭的制备与表征

以竹屑为原料,研究了KOH活化法高比表面积活性炭的制备工艺.分别考察了浸渍比、活化温度、活化时间等工艺参数对产品吸附性能的影响,并提出了可能的活化机理.在所研究的实验条件下,最佳的制备工艺是浸渍比1.0,活化温度800℃,活化时间2h.所得到的活性炭产品的比表面积和孔容可达2996m2/g和1.64cm3/g.该产品附加值高,在吸附领域特别是在双电层电容器的电极材料领域有广阔的应用前景.     

超级电容器用活性炭的制备与电化学表征

以煤焦油沥青为前驱体,采用化学活化法制备了超级电容器用高比表面活性炭和活性炭电极.考察了活化温度对活性炭电极比电容量的影响,研究了活性炭材料的比表面积和孔结构与活性炭电极的充放电性能之间的关系,并对活性碳电极进行了电化学表征.结果表明,在500～700℃,随着活化温度的提高,活性炭电极的比电容量显著增大,当活化温度超过700℃时,活性炭电极材料的比电容量变化不明显.700℃活化温度下所制备的活性炭材料呈现明显的多孔结构,孔容为1.038cm3/g,比表面积为1959m2/g;所制成的活性炭电极比电容量为210F/g,等效内阻为0.9Ω/cm2,10mA/cm2充放电500次后保持90%以上电容量,交流阻抗谱在频率低于转化点时表现出纯粹的电容行为,循环伏安曲线显示出良好的可逆特性.     

超高比表面积活性炭的制备与表征

以无患子残渣为原料,KOH与K2CO3作为活化剂,采用微波炭化和活化两步法制备超高比表面积活性炭,通过正交实验优化活性炭的制备工艺,探讨了碱炭比、活化温度和活化时间对活性炭吸附亚甲基蓝吸附值的影响。利用N2吸脱附实验、XRD、FT-IR等实验技术,对制备的活性炭结构与性能进行了表征。结果表明,在碱炭质量比为4∶1、活化温度800℃、活化时间30 min的条件下,所制备的活性炭对亚甲基蓝吸附值为595 mg/g,BET比表面积为3 479 m2/g,吸附累积总孔容达1.8262 cm3/g,平均孔径为2.0997 nm。     

Fabrication of hydrophobic regenerated activated carbon with high specific surface area

Activated carbon (AC) has been widely used in the prevention and control of air and water pollution due to its excellent adsorption ability. However, the adsorption capacity of AC for targeting organic compounds is reduced because of the competitive adsorption of water molecules. The current study proposes hydrophobic modification and regeneration of waste AC as a solution to these issues. Using waste AC as raw material, SiO₂ particles were introduced to increase its surface roughness and micropores of AC. Nonpolar alkyl chain groups were grafted on the surface of AC to improve its hydrophobic performance, and high-temperature regeneration was used to increase its specific surface area. The experimental results showed that the water contact angle of AC increased from 30° (hydrophilic) to 142° (hydrophobic) after modification, and it maintained an angle of 139° even after high-temperature regeneration. The specific surface area of hydrophobic AC increased from 290 to 1075 m² g^?1 and the equilibrium adsorption capacity of hydrophobic AC for methylene blue is 425.4 mg g^?1 after regeneration. AC-adsorbed methylene blue also has excellent hydrophobicity (145°) and high specific surface area (1250 m² g^?1) after being modified and regenerated by the same methods. After being exposed to air for 600 days, the modified AC still has good hydrophobicity (125°). This indicates that our method of hydrophobic modification combined with regeneration has great significance to the recovery and utilization of waste AC.

Graphical abstract

     

高比表面积活性炭研制进展

高比表面积活性炭具有发达的内部孔隙结构和超强的吸附性能,它作为一种新型材料在许多高效吸附功能材料领域有广阔的应用前景,如化工、制药、食品和环境保护等领域。本文综述了活性炭的制备方法和国内外活性炭的研制状况,展望了活性炭发展趋势,并就目前的两大研究热点高比表面积活性炭在双电层电容器和溶剂回收两大领域的应用进行了着重探讨。     

Sustainable porous hollow carbon spheres with high specific surface area derived from Kraft lignin

Hollow carbon spheres (HCSs) have attracted tremendous interest in recent years due to their intriguing structure-induced physicochemical properties and significant potential for numerous applications. However, the preparation of HCSs with precise structural control using a simple and scalable strategy remains challenging. In this work, hollow carbon particles having a well-defined spherical morphology were successfully produced using a green, economical, and facile spray drying method together with a carbonization process. Kraft lignin was employed as the carbon precursor in place of lignosulfonate with potassium hydroxide (KOH) as an activation agent. The high specific surface area (1536.5–2424.8 m² g^?1) with micro-mesoporous structure of HCSs can be easily tuned by controlling the mass ratio of KOH to carbon precursor. The KOH-to-lignin mass ratios were utilized below 1.5, lower than those in previous studies typically used higher than 3, which was in accordance with green chemistry principles. In addition, these HCSs have applications as electrode materials in supercapacitors for energy storage devices. With the great achievements and continuous efforts in this important field, these results suggest that our approach will open a new path for the development of advanced carbon materials and high value-added utilization of Kraft lignin as a promising material for potential applications.     

A novel way for preparing high surface area silica monolith with bimodal pore structure

The crack-free silica monolith with macropores and mesopores has successfully been achieved in the presence of citric acid as nonsurfactant via sol-gel reactions of tetramethoxysilane (TMOS). Citric acid was removed by calcination to afford monolithic bodies with high specific surface area of 648 m²/g, pore volume of 0.9 cm³/g. Poly (ethyl glycol) has been used together with citric acid to control the particle aggregation and internal structure. Macropores in the micrometer range originate from the spinodal phase separation and gelation kinetics. Textural mesopores in the 2–8 nm range are controlled through adding citric acid and postsynthesis treatment in ammonia solution. By employing the glycerol as drying control chemical additives (DCCA), cracks of the materials can be successfully avoided.