共查询到19条相似文献,搜索用时 125 毫秒
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表面改性对活性炭吸附性能的影响 总被引:1,自引:0,他引:1
采用浓硝酸对活性炭进行表面氧化处理,将得到的样品分别浸渍在银氨、硫酸铜及咪唑溶液中进一步改性,然后采用Boehm滴定法对改性活性炭表面酸性基团的含量进行测定,研究改性对活性炭吸附性能的影响。结果表明:通过上述改性,活性炭表面酸性基团发生了显著变化,特别是羧基含量增加较多,从而活性诙的吸附性能发生了相应的变化。 相似文献
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改性活性炭吸附处理含铬电镀废水的研究 总被引:1,自引:0,他引:1
分别采用硫酸和双氧水对活性炭迚行改性,测定了改性后活性炭的表面面积和含氧官能团数量,以改性后的活性炭为吸附剂,用于处理含铬电镀废水。考察了pH值、吸附时间和吸附剂用量等对Cr(VI)去除率的影响,并研究了其吸附等温线。研究表明,相比未改性活性炭,改性后的活性炭含氧官能团数量明显增加,并且改性后活性炭有利于对废水中Cr(VI)的吸附,经双氧水改性后的活性炭的吸附效果最好。 相似文献
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用硝酸对活性炭进行了表面改性,并在静态条件下,考察了超声波对改性活性炭吸附Cr(Ⅵ)的影响。结果表明,改性使活性炭表面酸性官能团数量显著增加;有/无超声作用下,活性炭对Cr(Ⅵ)的去除率均随pH值的升高而下降;无超声作用时Cr(Ⅵ)去除率随接触时间的延长持续上升至平衡,而超声作用下去除率先快速上升至近平衡,再小幅下降后又缓慢升至平衡;Cr(Ⅵ)去除率随超声波功率的增大而降低;Freundlich模型能更好描述该吸附过程,超声波的引入对活性炭吸附Cr(Ⅵ)有一定抑制作用。 相似文献
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采用NaOH和NaSiO3·9H2O对活性炭进行改性,在微波作用下利用改性活性炭处理氨氮废水.利用模拟氨氮废水考察了活性炭加入量,废水pH值、微波处理温度和微波辐照时间对氨氮去除率的影响.结果表明:在改性活性炭和微波辐照共同作用下,废水pH值对氨氮的去除率没有影响;活性炭对氨氮的吸附符合Langmuir吸附模型.在微波... 相似文献
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采用价格低廉的煤质柱状活性炭,分别通过硝酸和尿素液相浸渍后焙烧改性的方法,在活性炭的表面引入氧原子和氮原子,考察了氧和氮掺杂对乙炔氢氯化的影响。结果表明,硝酸改性后,活性炭的表面酸性基团大量增加,转化率及稳定性明显下降,而尿素改性的方法可成功地将氮掺入到活性炭的表面,氮掺杂量随焙烧温度的降低而提高,乙炔氢氯化活性随氮含量的增加而增加,和未改性的活性炭相比,其初始乙炔转化率从55%提高到70%,稳定性也得到了提高。 相似文献
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活性炭表面改性及其对Cr(Ⅵ)吸附性能的研究 总被引:12,自引:0,他引:12
分别用HNO3、H2SO4以及HNO3加乙酸铜溶液对活性炭进行了表面改性处理,测定了它们的表面化学性能,研究了改性活性炭对Cr(VI)吸附性能的影响。实验结果表明:通过上述改性,活性炭表面官能团数量发生了显著改变,特别是羧基增加较多;通过改性后的活性炭对Cr(Ⅵ)吸附性能有所提高。 相似文献
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Characterisation of the surface of oxidised carbon adsorbents 总被引:2,自引:0,他引:2
The surface reactivity and functional group content of a series of oxidised active carbons has been assessed by elemental analysis, electrophoretic mobility measurements and potentiometric titrations. Oxidation of carbons with hot air resulted in a greater proportion of relatively weak acidic surface functional groups (i.e., phenolic), whereas nitric acid modification produced a greater amount of carboxylic groups. Electrophoretic mobility measurements suggest that the carbon surface is negatively charged within the range of the pH values studied. pH titration results indicate that the surface acidity of active carbons is stronger than that of a commercial polymeric carboxylic acid ion exchange resin. Possible mechanisms of carbon surface oxidation are discussed. 相似文献
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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。 相似文献
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The physicochemical properties and the surface chemical structure of the carbon materials obtained by the modification of the commercial activated carbon D43/1 (Carbo-Tech, Essen, Germany) were studied. The previously de-ashed activated carbon was subjected to the following modification procedures: high-temperature treatment (1000 K) under vacuum; oxidation with conc, nitric acid; and ammonia-treatment of annealed and oxidised carbons at high temperatures. The porous structure and the surface area of the five different carbon samples obtained were estimated by means of mercury porosimetry and from low-temperature nitrogen adsorption data. The thermogravimetric analysis and the quantitative determination of surface functional groups by selective neutralisation of bases and pH-metric titration were carried out. FTIR spectra (transmission) and X-ray photoelectron spectra (Cls, Ols and Nls) were obtained for all the carbon samples and compared with one another. The changes in the porosity and the chemical properties of the carbon surface caused by the modification were analysed. Some possible surface functional species, their structure and surface state are discussed. 相似文献
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Surface modification of a granular activated carbon by citric acid for enhancement of copper adsorption 总被引:4,自引:0,他引:4
In this study, citric acid was used to modify a commercially available activated carbon to improve copper ion adsorption from aqueous solutions. The carbon was modified with 1.0 M citric acid, followed by an optional step of reaction with 1.0 M sodium hydroxide. It was found that the surface modification reduced the specific surface area by 34% and point of zero charge (pHpzc) of the carbon by 0.5 units. Equilibrium results showed that citric acid modification increased the adsorption capacity to 14.92 mg Cu/g, which was 140% higher than the unmodified carbon. Higher initial solution pH resulted in higher copper adsorption. The chemical surface modification adversely affected the copper adsorption rate. Adsorption kinetic mechanisms were investigated with an intraparticle diffusion model. It was found that the modification did not change both external diffusion and intraparticle diffusion. 相似文献
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膜分离技术制备高纯单宁酸的研究 总被引:6,自引:0,他引:6
工业单宁酸经改性活性炭预处理后,用超滤和纳滤技术纯化的方法制备高纯度单宁酸。重点考察了料液质量分数、操作压力差、料液温度对膜分离效果的影响。确定的最佳工艺条件是:料液质量分数 15%、截留相对分子质量为 6000 的超滤膜和截留相对分子质量为600的纳滤膜的操作压力差分别为 0.10 MPa 和 0.08 MPa、料液温度 40℃。同时探讨了颗粒活性炭通过硝酸氧化改性增强其吸附性能的方法。分析结果表明,膜分离技术有效地实现了不同分子质量的物料分级和截留,精品单宁酸的含量为 97.3%,收率为 84.7%。 相似文献
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载体预处理对Pd/C催化剂催化性能的影响 总被引:1,自引:0,他引:1
研究了活性炭硝酸表面改性对以其为载体制备的负载钯催化剂性能的影响。利用表面官能团滴定、N2物理吸附和扫描电镜对催化剂进行表征,以邻硝基氯苯催化加氢制备2,2'-二氯氢化偶氮苯反应为模型反应对催化剂的性能进行评价。结果表明,经过不同浓度的HNO3处理,活性炭孔结构性能变化不大,但是活性炭表面酸性含氧基团的浓度有了较大程度的增长,为Pd金属粒子的沉积提供了大量的吸附位,提高了Pd金属的分散度,从而制得高活性的Pd/C催化剂。通过30%HNO3 60 ℃水浴中回流4 h处理的活性炭可以达到最佳效果,所制得催化剂的活性是以未经硝酸处理过的活性炭载体制备的催化剂活性的2.3倍。 相似文献