炭材料在水污染修复领域的应用研究

针对炭材料在水污染修复领域发挥的重要作用,对以活性炭(粉状、粒状及纤维状)和膨胀石墨为主的炭材料吸附技术、微生物与炭材料复合构成的生物炭材料吸附降解技术以及二者与其它技术(如臭氧氧化、膜过滤及光催化等)耦合用于水处理的应用研究现状进行了概述,指出新型炭材料(如活性炭纤维和膨胀石墨)吸附技术、生物炭材料吸附降解技术及相关耦合技术极具应用前景,并对今后的研究提出了建议.     

作为新型炭吸附剂的合成活性炭

合成树脂和共聚物长时间以来被用于制备炭。可是,只有在我们的研究中,才将这一类吸附剂列入特殊炭类,这就是合成活性炭。多孔苯乙烯球和乙烯基吡啶的共聚物以及特别发展的酚醛树脂,经过热解,随后进行活化,合成活性炭便告制成。对它们进行对比研究后表明:以上基质制得的SCN、SCS和SCP合成炭,大大不同于天然原料制得的工业活性炭,因为前者有下列各项综合性质:     

酚醛树脂炭/石墨复合炭材料用作锂离子电池负极材料的考察

用不同的方法在石墨的表面包覆上一层酚醛树脂,然后在Ｎ２保护下１０００℃炭化１ｈ制得复合炭材料,并用扫描电子显微镜（ＳＥＭ）对其表面物理形态进行观察分析,研究了复合炭材料的恒电流充放电性能。包覆在石墨表面的具有无定形结构的酚醛树脂炭能够有效阻止石墨在充放电过程中发生层状剥落,从而提高复合炭材料的循环稳定性,其中通过常常法制香的复合炭材料（ＣＰＧ－３０）在十次循环后可逆容量为３２６ｍＡｈ．ｇ＾－１,比     

试验性炭材料的性能和应用

目前,用合成共聚物和树脂制活性炭已成为普遍研究的课题。这种炭材料没有杂质,而且通过对原材料选择和处理的方法可控制其元素组成和孔结构。由于合成炭具有许多独特的优点,故被用于最危急的情况下,如在医学上用于碱液的吸附解毒。     

炭材料在医药学方面的应用

一、炭材料在人工器官方面的应用六十年代末,十分意外地发现某些炭表面具有罕见的固有抗血栓性质。这一发现吸引了一些医学工作者和炭材料科学工作者进行有关炭的血液相容性,以及其与晶体结构和表面化学及表面形态学之间关系的研究。这导致了炭材料在各类人工器官中的广泛应     

多孔炭材料在电双层电容中的应用

炭材料具有优良的耐高温、耐腐蚀、导电等特性,长期以来被人们用作各种各样的电极材料和集电体,如食盐电解用人造石墨电极。电解铝用电极,炼钢用电极等。炭棒则早已在普通锰干电池中作电极导电材料。近年来,由于多孔质炭材料的特殊性能,它们在新型电子能源中的应用进一步得到开发,限于篇幅本文主要概述它们在电双层电容发展的现况,以期促进我国在这方面的应用开发。     

纳米多孔材料炭气凝胶及其在电吸附领域的应用

炭气凝胶作为一种新型具有特殊无定型结构的功能材料引起了各国研究者的极大兴趣.随着电吸附理论的发展,炭气凝胶日益成为具有诱人发展前景的电吸附材料.阐述了炭气凝胶的发展、研究动态及应用前景,探讨了电吸附理论及其基本原理,着重就炭气凝胶在电吸附领域的工业应用进行论述.     

电纺丝制备掺氮多孔炭纳米纤维布用作锂离子电池负极材料

选取聚丙烯腈和三聚氰胺为碳前驱体和氮前驱体,通过电纺丝和后续的炭化和水蒸气活化过程,制备了一种具有自支撑结构,无需任何导电剂和粘结剂,直接用作电极的用于锂离子电池负极的掺氮多孔炭纳米纤维布。结果表明,此多孔炭纳米纤维布具有无纺交联的纳米纤维形态、独特的微孔结构、较高的比容量(856 m Ah·g-1)和较好的功率性能,是一种非常有使用前景的锂离子电池负极材料。     

新型炭吸油材料的表征

为了解决环境污染中油污染的问题,世界各国相继投入大量的财力开发新型高效吸油材料.本研究针对多孔炭材料中膨胀石墨(EG)和植物炭疏水亲油的特点,分别以重油和20号柴油为吸附质,对膨胀石墨和炭化玉米秸秆、炭化油菜秸杆和炭化竹子3种植物炭的吸油特性和影响因素进行了详细的表征和研究.实验结果表明(1)蠕虫状膨胀石墨样品具有最大的吸油率,理想状态下可以达到80 kg/kg EG;(2)油类的粘度在很大程度上影响吸附速率,从而在很大程度上影响等温吸附曲线的形状;(3)膨胀石墨的循环再利用性能比较差;(4)3种代表性植物炭材料中,炭化玉米秸杆对20#柴油的吸附率最高,其次为炭化油菜秸秆,最小的是炭化竹子;(5)比表面积的改变,对液态吸附过程影响不大.     

沥青炭包覆微晶石墨用作锂离子电池负极材料的研究

针对微晶石墨振实密度低和首次库仑效率低的缺点,采用真空浸渍-炭化工艺对微晶石墨进行沥青炭包覆改性,利用XRD、拉曼光谱和SEM等分析了炭包覆前后微晶石墨的结构和表面形貌,利用比表面测试仪测试了样品的BET比表面积,利用振实密度仪测定振实密度,并通过恒电流充放电和循环伏安等测试了样品的电化学性能。结果表明,炭包覆后微晶石墨的石墨化度略有降低,拉曼R值由0.63增大至0.85;颗粒表面更光滑平整,BET比表面积降低0.9m2/g,振实密度从0.95g/cm3提高至1.08g/cm3;不可逆容量损失从121mAh/g减小到44mAh/g,可逆容量从300mAh/g提高到320mAh/g,首次库仑效率从71.2%提高到87.4%,而且循环性能得到明显改善。     

Use of adsorption using granular activated carbon (GAC) for the enhancement of removal of chromium from synthetic wastewater by electrocoagulation

The present work deals with removal of hexavalent chromium from synthetic effluents in a batch stirred electrocoagulation cell with iron-aluminium electrode pair coupled with adsorption using granular activated carbon (GAC). Several working parameters such as pH, current density, adsorbent concentration and operating time were studied in an attempt to achieve higher removal capacity. Results obtained with synthetic wastewater revealed that most effective removal capacities of chromium (VI) could be achieved when the initial pH was near 8. The removal of chromium (VI) during electrocoagulation, is due to the combined effect of chemical precipitation, coprecipitation, sweep coagulation and adsorption. In addition, increasing current density in a range of 6.7-26.7mA/cm2 and operating time from 20 to 100min enhanced the treatment rate to reduce metal ion concentration below admissible legal levels. The addition of GAC as adsorbent resulted in remarkable increase in the removal rate of chromium at lower current densities and operating time, than the conventional electrocoagulation process. The method was found to be highly efficient and relatively fast compared to existing conventional techniques.     

Effects of adsorptive properties of biofilter packing materials on toluene removal

Various adsorptive materials, including granular activated carbon (GAC) and ground tire rubber (GTR), were mixed with compost in biofilters used for treating gaseous toluene, and the effects of the mixtures on the stability of biofilter performance were investigated. A transient loading test demonstrated that a sudden increase in inlet toluene loading was effectively attenuated in the compost/GAC biofilter, which was the most significant advantage of adding adsorptive materials to the biofilter packing media. Under steady conditions with inlet toluene loading rates of 18.8 and 37.5 g/m³/h, both the compost and the compost/GAC biofilters achieved overall toluene removal efficiencies greater than 99%. In the compost/GAC mixture, however, biodegradation activity declined as the GAC mass fraction increased. Because of the low water-holding capacity of GTR, the compost/ground tire mixture did not show a significant improvement in toluene removal efficiency throughout the entire operational period. Furthermore, nitrogen limitations affected system performance in all the biofilters, but an external nitrogen supply resulted in the recovery of the toluene removal efficiency only in the compost biofilter during the test periods. Consequently, the introduction of excessive adsorptive materials was unfavorable for long-term performance, suggesting that the mass ratio of the adsorptive materials in such mixtures should be carefully selected to achieve high and steady biofilter performance.     

Mathematical model of the non-steady-state adsorption and biodegradation capacities of BAC filters

This research was focused on developing a non-steady-state numerical model to differentiate the adsorption and biodegradation quantities of a biological activated carbon (BAC) column. The mechanisms considered in this model included adsorption, biodegradation, convection and diffusion. Simulations were performed to evaluate the effects of some parameters such as specific biodegradation rates and diffusivities on adsorption and biodegradation performances for the removal of dissolved organic matter from water. The results show that the developed model can predict the experimental data well. The biofilm developed around the BAC granules can hinder the mass transfer of the substrate onto the GAC surface, and the adsorption process will be restricted by the biofilm thickness. Although increasing the specific biodegradation rate can increase the performance of biodegradation, the adsorption efficiency will be decreased by lowering the boundary concentration in the interface of GAC. On the contrary, increasing the diffusivity can increase both the adsorption and biodegradation efficiencies simultaneously; so that the overall removal efficiency can be promoted through the improvement of mass transfer.     

Toluene sorption by granular activated carbon and its use in cold regions permeable reactive barrier: Fixed bed studies

Sorption characteristics of toluene on a granular activated carbon (GAC) derived from coconut shell have been investigated at 4 and 20 °C to facilitate the development of a permeable reactive barrier (PRB) to treat oil-contaminated surface and sub-surface waters in cold regions. A one-dimensional solute transfer model describing quantitatively the equilibrium and kinetics of sorption of toluene on GAC fixed-bed reveals that breakthrough and saturation capacities reduce with increased water flow rates. The GAC sorption capacity in a fixed bed is between 30 and 60% of the capacity determined in equivalent batch system. Fixed-bed performance is also significantly reduced at low temperature, with breakthrough and saturation capacities at 4 °C between 20 and 30% less than the values at 20 °C. The detrimental effect of low temperature on fixed bed performance will have significant implications for the PRB design to treat contaminated waters in cold regions and should be considered at planning stage.     

用SEM和XRD研究改性活性炭纤维的结构

比较了以ＦｅＳＯ４改性ＡＣＦ其表面形态及微晶结构的变化。经过改性，ＡＣＦ表面形态发生了很大变化—表面被刻蚀，表面孔形态发生变化，ＡＣＦ的石墨微晶尺寸大大减小，出现明显的细晶化趋势。ＳＥＭ和ＸＲＤ两种测试方法的结果基本吻合，在此基础上提出改性模型     

炭气凝胶/活性炭复合电极在有机电解液体系双电层电容器中的阻抗

分别以炭气凝胶(CAG),炭黑(CB)以及石墨(G)为导电剂与KOH活化法高比表面积活性炭(HSAC)制备复合电极,组装成双电层电容器,在(C2H5)4NBF4/丙烯碳酸盐电解液体系中进行交流阻抗测试分析。应用动力学及电子传递控制的等效电路模型对各电极的实验阻抗数据进行拟合得到相应的模型参数,串联溶液电阻Rs、极化电阻Rp、能斯特边界层厚度δ及平均孔内离子扩散系数D。结果表明,炭气凝胶复合电极的孔内离子扩散系数D最高,极化电阻Rp与炭黑复合电极接近。炭气凝胶电极的内阻为各电极中最低并且具有最高的比电容。     

载锰活性炭纤维(SACF-Mn)的制备及对乙基硫醇吸附性能的研究ⅠSACF-Mn的制备及结构研究

制备了载锰剑麻基活性炭纤维（ＳＡＣＦ－Ｍｎ），并研究了制备条件对ＳＡＣＦ－Ｍｎ的结构及表面形态的影响。研究表明：增大锰溶液的浓度，提高ｐＨ值，高价态的锰离子都有利于ＳＡＣＦ对锰的吸附；锰化合物的阴离子类型，不仅影响ＳＡＣＦ对锰的吸附，而且对载锰后ＳＡＣＦ的表面形态的影响更显著     

Electrochemical degradation of amaranth aqueous solution on ACF

The degradation of Amaranth, a kind of azo dye, has been studied under galvanostatic model with activated carbon fiber (ACF) electrode in aqueous solution with electrochemical method. The ACF was used as anode and cathode, respectively for the decolorization process. The onset oxidation potential and reduction potential for Amaranth on ACF were respectively ascertained at 0.6 and -0.4 V. During the range of -1.1 to 0.50 mA cm(-2), the decolorization was clarified into three processes as electroreduction, adsorption and electrooxidation. There were little contributions to the color and COD removals for the process of adsorption. The color removal can be up to 99% when the current density was 0.50 mA cm(-2). The maximum COD removal was 52% for the process of electrooxidation. Hundred percent color removal was obtained when the current density of -1.0 mA cm(-2) was applied. The maximum COD removal was 62% for the electroreduction. The COD removal results from the adsorption of products for the decolorization process of electrooxidation or electroreduction.     

Comparisons of sorbent cost for the removal of Ni2+ from aqueous solution by carbon nanotubes and granular activated carbon

The reversibility of Ni2+ sorption by NaOCl oxidized single-walled carbon nanotubes (SWCNTs), multiwalled carbon nanotubes (MWCNTs) and granular activated carbon (GAC) was investigated to evaluate their repeated availability performance in water treatment. Under the same conditions, the SWCNTs and MWCNTs possess more Ni2+ sorption capacities and show better reversibility of Ni2+ sorption and less weight loss after being repeated sorption/desorption processes than the GAC, suggesting that they are effective Ni2+ sorbents and can be reused through many cycles of water treatment and regeneration. A statistical analysis on the replacement cost of these sorbents revealed that SWCNTs and MWCNTs can be possibly cost-effective Ni2+ sorbents in water treatment regardless of their high unit cost at the present time.     

活性炭纤维过滤器祛除室内气态污染物的实验研究

以平板、旁通、折叠三种结构形式的活性碳纤维过滤器为实验对象，选择甲醛和氨气作为室内典型污染物，以分光光度法测定在变风量和变污染物浓度的条件下过滤器的吸附过滤效果；实验数据的分析表明，从综合角度考虑，平板式过滤器较为理想，折叠式效率较高，但阻力相对偏大，而旁通式则效率偏低；提出了一些对活性碳纤维过滤器的发展和改进有价值的建议。