磷酸活化法活性炭的吸附性能和孔结构特性

采用磷酸活化法在不同操作条件下制备得到各种活性炭,实验测定了相应活性炭的亚甲蓝吸附值、氮气吸附等温线及活性炭的比表面积和孔容。分别研究了磷酸活化法制备活性炭的主要操作参数,如浸渍比、活化时间和活化温度对活性炭吸附性能和活性炭的孔结构特征的影响。实验结果表明,浸渍比是磷酸活化法制备活性炭的最重要的影响因素。综合考虑活性炭的吸附性能和孔结构特征受活化操作参数的影响规律,探讨了磷酸活化法生产木质活性炭的最优操作参数。在实验范围内,磷酸活化法制备木质活性炭的最优操作条件宜选择浸渍比为100％～150％、500℃左右活化温度和60～90min的活化时间。     

直接合成法制备载银稻壳活性炭及其对苯并噻吩的吸附

分别采用直接合成法和浸渍法制备了载银稻壳活性炭脱硫吸附剂,通过N2吸附-脱附、TEM及XRD测试手段对其进行表征,通过静态吸附实验研究了载银稻壳活性炭对苯并噻吩的吸附性能。结果表明,直接合成法在活化稻壳制得活性炭的同时将银颗粒均匀地负载在活性炭的表面;与浸渍法相比,直接合成法上的活性组分分散更均匀,粒径更小,且NO3-在稻壳活化过程中也起到了增加活性炭比表面积、孔体积和孔径的作用。通过对比实验证明了直接合成法制备的载银活性炭对模拟汽油中的苯并噻吩具有较高的吸附容量,30℃时,模拟汽油中的硫含量为542.6 ppm,吸附剂的硫吸附容量达到了15.58 mg/g。     

木棉基活性炭纤维的结构与吸附性能

采用浸渍磷酸氢二铵及化学活化法制备了3种木棉基活性炭纤维,其中AK-1没有经过预氧化处理,AK-2先浸渍再经预氧化处理,AK-3先经预氧化处理再浸渍;表征了3种活性炭纤维的表面物理化学结构及吸附性能。结果表明:3种活性炭纤维的平均孔径均约为2nm;预氧化处理提高了纤维的比表面积和纤维表面的含氧基团含量。AK-1具有最大的苯酚吸附量为65.8mg/g;AK-3具有最大的亚甲基蓝吸附量为156.7mg/g;AK-2具有最大的比表面积为1518m2/g和最多的表面含氧基团,对苯酚和亚甲基蓝的吸附量均不高,说明表面含氧基团降低了纤维对苯酚和亚甲基蓝的吸附量。吸附动力学研究表明,木棉基活性炭纤维吸附苯酚和亚甲基蓝符合拟二级动力学方程。     

油茶壳残渣制备活性炭的工艺

以油茶壳醇浸取后残渣为原料,以磷酸活化法制备活性炭,考察了浸渍比、磷酸质量分数和活化温度等对活性炭吸附性能及其得率的影响;活性炭的吸附性能由碘吸附值、亚甲基蓝吸附值表征。结果表明,在酸/炭浸渍比为3:1、磷酸质量分数70%、活化温度500℃时,活性炭的吸附性能最佳,其碘、亚甲基蓝吸附值和得率分别为1043.29mg/g、148.5mg/g和38.77%。采用物理吸附仪在77K下测定其N₂吸附脱附等温线,利用BET法和BJH法计算比表面积和孔径分布,其比表面积为1626.45m²/g,平均孔径为4.7nm,总孔容为1.94cm³/g。同时采用FTIR和XRD分析了活性炭的表面官能团和微观结构。     

玉米芯活性炭的制备及其吸附性能的实验研究

以玉米芯为原料,磷酸为活化剂制备玉米芯活性炭。当浸渍比（H3PO4：玉米芯）为3时,在400℃活化90min后,玉米芯活性炭对亚甲基蓝溶液的脱色率和收率最好。吸附剂对于含铅废水具有良好的吸附性能。当废水的pH为5,溶液的初始浓度为40mg／L,吸附剂投加量为0．2g,吸附时间为120mm时,其去除率高达90％左右。研究对利用废旧农作物制备活性炭具有一定的应用前景。     

活性炭改性及其对乙硫醇吸附性能的研究

以活性炭为基础吸附剂,考察不同类型活性炭的吸附性能以及不同改性方法对活性炭吸附性能的影响。乙硫醇的吸附性能通过变压吸附装置所得的穿透曲线评价。采用低温氮气吸附脱附表征吸附剂的比表面积和孔径分布;结果显示椰壳活性炭具有较大的吸附量。通过氧化、酸碱和浸渍金属离子改性椰壳活性炭发现,负载铁离子的吸附性能最好,吸附量为122.4mg/L,提高幅度为48.5%。     

磷酸法海藻基活性炭的制备及吸附性能

以大型海藻铜藻为原料,采用H_3PO_4活化法制备活性炭,考察磷酸与藻粉的浸渍比、浸渍时间、活化温度、活化时间对得率、亚甲基蓝吸附值、碘吸附值的影响。H_3PO_4活化法制备活性炭最佳工艺如下:磷酸与藻粉的质量比为5∶1,浸渍时间100 min,活化温度550℃,活化时间75 min。最佳制备条件下制得的活性炭碘吸附值为528. 8 mg/g,亚甲基蓝吸附值为142. 5 mg/g,得率为43. 74%,比表面积为728. 73 m2/g。pH=2条件下,铜藻基活性炭对于Cr(Ⅵ)最大吸附量和吸附率可分别到达31. 5 mg/g和85%。     

低浓度氰化氢在浸渍活性炭上的吸附净化研究

采用浸渍法改性活性炭吸附脱除低浓度氰化氢(HCN),研究了NaOH与磺化酞菁钴(CoPcS)混合浸渍改性活性炭净化HCN的性能。研究表明:改性炭在制备过程中适当增加NaOH的浓度有利于提高其吸附HCN的能力,当NaOH浸渍液浓度为10%时,CoPcS/NaOH配比0.15mg·g-1、焙烧温度350℃为最佳制备条件;吸附反应阶段较适宜的体积空速为923h-1、氧体积分数2%、吸附温度为90℃。N2吸附表征了活性炭的比表面积和孔结构性质,与原活性炭相比,CoPcS与NaOH混合浸渍改性活性炭的比表面积和孔体积有所降低,但对HCN的吸附能力却显著提高,说明HCN与浸渍剂在活性炭表面发生了化学反应;孔径分布说明HCN在改性炭的中孔或大孔上参与化学吸附造成微孔扩充,而不是微孔填充和覆盖。     

磷酸活化法制备花生壳活性炭工艺

采用正交试验方法探讨了以花生壳为原料,通过磷酸活化法制备的高效活性炭吸附剂。以活性炭的收率和Pb2+吸附容量为考察指标,选择了磷酸质量浓度、浸渍质量比和活化温度3个因素,3个水平的正交试验方法。结果表明,对活性炭收率影响最大的因素是活化温度,对活性炭吸附Pb2+容量影响最大的是磷酸活化剂的质量浓度。综合考察各影响因素,得出在磷酸活化剂质量浓度为1 220 kg/m3,浸渍质量比为150%和活化温度为400℃时可以在保持活性炭收率较高的情况下制备高Pb2+吸附容量的花生壳活性炭吸附剂,该活性炭的比表面为1 018.5 m2/g,总孔容积为0.754 m3/g,平均孔径为2.961 nm,对低质量浓度含铅废水中铅离子的去除率接近100%,是合适的液相吸附用活性炭材料。     

活化剂对活性炭处理矿山废水Mn2+的影响研究

采用HCl、KCl、NaOH和Fe(NO_3)_3四种活化剂预处理褐煤,制备得到了活性炭吸附剂,分析了不同活化剂处理获得的褐煤活性炭的比表面积、孔容和吸附性能,研究了不同活化剂处理对活性炭吸附废水中Mn~(2+)的影响。结果表明:负载KCl制备得到的煤基活性炭比表面积和孔容最大;在吸附剂投加量为5 g,温度为25℃,pH=7,吸附时间为60 min时,对水体中的Mn~(2+)去除率顺序为:K-ACNa-ACH-ACSL-ACFe-AC,K-AC对Mn~(2+)的去除率达到97.4%。     

Adsorption of hydrogen sulphide (H2S) by activated carbons derived from oil-palm shell

Adsorption of hydrogen sulphide (H₂S) onto activated carbons derived from oil palm shell, an abundant solid waste from palm oil processing mills, by thermal or chemical activation method was investigated in this paper. Dynamic adsorption in a fixed bed configuration showed that the palm-shell activated carbons prepared by chemical activation (KOH or H₂SO₄ impregnation) performed better than the palm-shell activated carbon by thermal activation and a coconut-shell-based commercial activated carbon. Static equilibrium adsorption studies confirmed this experimental result. An intra-particle Knudsen diffusion model based on a Freundlich isotherm was developed for predicting the amount of H₂S adsorbed. Desorption tests at the same temperature as adsorption (298 K) and at an elevated temperature (473 K) were carried out to confirm the occurrence of chemisorption and oxidation of H₂S on the activated carbon. Surface chemistries of the palm-shell activated carbons were characterized by Fourier transform infrared spectroscopy and Boehm titration. It was found that uptaking H₂S onto the palm-shell activated carbons was due to different mechanisms, e.g. physisorption, chemisorption and/or H₂S oxidation, depending on the activation agent and activation method.     

Adsorption Equilibrium and Fixed Bed Adsorption of Aniline onto Polymeric Resin and Activated Carbons

The adsorption of aniline on several adsorbents including resin Sepabeads SP206 and activated carbons Jacobi and Norit, has been studied. The influence of temperature in the adsorption capacity was obtained by batch method. Langmuir and Bi-Langmuir were the best models to represent the equilibrium sorption isotherm of aniline in the resin and the activated carbons, respectively. Higher adsorption capacity was obtained for both activated carbons than that for resin, being the maximum adsorption capacity three times higher. Nevertheless, the aniline adsorption capacity onto resin is much more influenced by the temperature.

The dynamic behavior of aniline onto Sepabeads SP206 resin and activated carbon Jacobi was also studied. Breakthroughs and reverse breakthroughs were carried out in a laboratory-scale column to study the adsorbent regeneration. A Linear Driving Force (LDF) model was used to predict the experiments for the two adsorbents. The results demonstrated that Sepabeads SP206 resin can be easily regenerated by using water, while around 50% of aniline remains adsorbed in the activated carbon. Furthermore, after 4 cycles of adsorption-desorption, only around 60% of aniline can be recovered from the activated carbon Jacobi; this behavior can be explained by the aniline that is chemically adsorbed into the activated carbon.     

On the interactions of phenol, aniline and p-nitrophenol on activated carbon surfaces as detected by TPD

The interactions of phenol, aniline and p-nitrophenol, adsorbed from aqueous solutions, with the surface of two activated carbons (with and without oxygen surface groups) were followed by temperature programmed desorption, thermogravimetry and analysis by mass spectrometry. The results reveal that on bare surface the three molecules can be presented as physisorbed and chemisorbed species. When oxygen surface groups are introduced on the carbon surface, there is a change in the adsorption/desorption behaviour; in such a way that the phenol chemisorption is inhibited and that decomposition of aniline and nitrophenol are originated.     

中高温环境下VOCs在活性炭上的吸附性能研究

选用3种商用活性炭及其分别经HCl溶液和KOH溶液浸渍改性的商用活性炭,研究中高温烟气环境下,反应空速、吸附温度对挥发性有机物（VOCs）吸附性能的影响,以及VOCs种类、吸附剂特性等与VOCs吸脱附效果的关系。研究发现：空速对吸附穿透时间影响较大,但对饱和吸附量影响不显著。吸附温度与VOCs浓度对饱和吸附量存在较大影响,150℃时甲苯的饱和吸附量仅能达到90℃时的40％。高沸点吸附质更易被吸附,更难被脱附。     

Coniferous Wood Sawdust-based Activated Carbons as Adsorbents Obtained with the Use of Microwave Radiation

Activated carbons were prepared by physical and direct activation of sawdust pellets coming from coniferous trees, with the use of microwave radiation. The activated carbons obtained were used as adsorbents for the removal of methylene blue (MB) from aqueous solutions. Liquid-phase adsorption experiments were conducted and the maximum adsorption capacity of each activated carbon sample was determined. The effects of activation procedure as well as adsorption tests parameters i.e., temperature, pH, initial methylene blue concentration, and contact time on the sorption capacity of each activated carbon were investigated. The kinetic models for MB adsorption on the activated carbons were also studied. Better fit to the experimental data was obtained with the Langmuir isotherm than Freundlich one, for all samples.     

Adsorption of sulfur dioxide onto activated carbons prepared from oil‐palm shells impregnated with potassium hydroxide

Adsorption of sulfur dioxide (SO₂), a gaseous pollutant, onto activated carbons prepared from oil‐palm shells pre‐treated with potassium hydroxide (KOH) impregnation was studied. Experimental results showed that SO₂ concentration and adsorption temperature affected significantly the amount of SO₂ adsorbed and the equilibrium time. However, sample particle sizes influenced the equilibrium time (due to effect of diffusion rate) only. Desorption at the same temperature of adsorption and a higher temperature of 200 °C confirmed the presence of chemisorption due to pre‐impregnation. Impregnation with different activation agents was found to have limited effect on the inorganic components of the sample. Compared with the activated carbon pre‐treated with 30% phosphoric acid (H₃PO₄) that had larger BET and micropore surface areas, the sample impregnated with 10% KOH had a higher adsorptive capacity for SO₂, which was closely related to the surface organic functional groups of the sample. In general, the activated carbon prepared from oil‐palm shell impregnated with KOH was more effective for SO₂ adsorption and its adsorptive capacity was comparable to some commercial activated carbons. © 2000 Society of Chemical Industry     

铁-钨-磷合金电沉积工艺及其性能研究

在含FeSO4·7H2O、Na2WO4·2H2O、NaH2PO2·H2O、Na3C6H5O7·2H2O、C6H8O7·H2O、NH3·H2O和苯亚磺酸钠的碱性镀液中,电沉积得到Fe–W–P三元合金,分析了不同镀液成分时所得镀层的化学组成,讨论了温度、pH、电流密度及NH3·H2O用量对镀层沉积速率和显微硬度的影响。结果表明:除NaH2PO2·H2O外,镀液中其他组分对镀层组成均有显著影响;工艺参数的改变对镀层沉积速率和显微硬度有一定影响,NH3·H2O体积分数对沉积速率的影响尤其显著。电沉积所得Fe–W–P合金镀层具有典型的非晶态结构,其耐蚀性略优于00Cr17Ni14Mo2不锈钢。     

Effects of activated carbon surface chemistry and pore structure on the adsorption of organic contaminants from aqueous solution

The objective of this research was to develop activated carbon selection criteria that assure the effective removal of trace organic contaminants from aqueous solution and to base the selection criteria on physical and chemical adsorbent characteristics. To systematically evaluate pore structure and surface chemistry effects, a matrix of activated carbon fibers (ACFs) with three activation levels and four surface chemistry levels was prepared and characterized. In addition, three granular activated carbons (GACs) were studied. Two common drinking water contaminants, relatively polar methyl tertiary-butyl ether (MTBE) and relatively nonpolar trichloroethene (TCE), served as adsorbate probes. TCE adsorbed primarily in micropores in the 7-10 Å width range while MTBE adsorbed primarily in micropores in the 8-11 Å width range. These results suggest that effective adsorbents should exhibit a large volume of micropores with widths that are about 1.3 to 1.8 times larger than the kinetic diameter of the target adsorbate. Hydrophobic adsorbents more effectively removed both TCE and MTBE from aqueous solution than hydrophilic adsorbents, a result that was explained by enhanced water adsorption on hydrophilic surfaces. To assure sufficient adsorbent hydrophobicity, the oxygen and nitrogen contents of an activated carbon should therefore sum to no more than about 2 to 3 mmol/g.     

复分解法生产磷酸二氢钾的新工艺

研究了以液氨、氯化钾和湿法磷酸为原料，通过复分解法生产磷酸二氢钾的工艺，确定复分解反应的最佳反应条件为：氨与磷酸物质的量比为1．05：1，氯化钾与磷酸物质的量比为1．1：1，反应时间为50min，反应温度为70—80℃，所得磷酸二氢钾达到HG2321-1992质量标准，可作为农业高效复合肥料。该工艺简单，能耗和原料消耗低，原料综合利用率高，生产过程无三废产生。     

Preparation of activated carbons by utilizing solid wastes from palm oil processing mills

Feasibility of producing activated carbons by utilizing solid wastes (extracted flesh fibre and seed shell) from palm oil processing mills was investigated. The effects of activation conditions (CO₂ flow rate, activation temperature and retention time) on the characteristics of the activated carbons, i.e. density, porosity, BET surface area, pore size distribution and surface chemistry were studied. In this study, the optimum conditions for activation were an activation temperature of 800 °C and a retention time of 30 min for fiber or 50 min for shell, which gave the maximum BET surface area. Pore size distribution revealed that the shell-based activated carbons were predominantly microporous whilst fiber activated carbon had predominant mesopores and macropores, suggesting the application of shell and fiber activated carbon as adsorbents for gas-phase and liquid-phase adsorption, respectively. This was confirmed by further gas- and liquid-phase adsorption tests.