活性炭的改性条件及其对硫化氢吸附性能的影响

以工业活性炭为载体制备改性活性炭,对比研究了未改性活性炭,NaOH、Na2CO3、Fe(NO3)3、Cu(Ac)2改性活性炭及挂膜硫氧化细菌后活性炭在相同条件下对硫化氢穿透时间及吸附容量的影响。结果表明：在相同控制条件下,NaOH改性活性炭明显优于其它改性剂;不同梯度改性剂条件下,20% NaOH改性活性炭对硫化氢的吸附效果最好,吸附穿透容量为78.25 mg/g,穿透时间可以达到2000 min以上;不同改性剂挂膜硫氧化细菌后对硫化氢均有一定的处理效果,其中对已达到饱和吸附的NaOH改性活性炭挂膜后的再生效果可以达到100%以上,说明挂膜硫氧化细菌活性炭对硫化氢的处理具有很好的效果。     

改性活性炭吸附处理含铅废水的研究

本文采用十二烷基硫酸钠(SDS)对活性炭进行改性,采用静态吸附法探究改性剂浓度及改性时间对Pb2+去除率的影响.确定最佳改性条件后,探究了pH、吸附时间及吸附温度对SDS改性活性炭(SDS-AC)吸附Pb2+的吸附性能的影响.实验表明:(1)当浓度为5 mmol/L、改性时间为10 min时,SDS-AC对Pb2+的吸...     

Co改性活性炭吸附NO的实验研究

采用Co(NO_3)_2对活性炭进行改性,考察浸渍浓度和吸附温度等条件对活性炭吸附NO性能的影响,并对已吸附NO的0.3 mol·L~(-1)的Co(NO_3)_2改性活性炭进行再生。通过BET、SEM、吸附等温线和FT-IR表征样品的比表面积、颗粒形貌和表面官能团。结果表明,当浸渍溶液浓度为0.3 mol·L~(-1)时,吸附效果最佳,80 min时吸附效率达88.90%。活性炭的吸附效率随着温度升高而降低,用0.3 mol·L~(-1)Co(NO_3)_2改性的活性炭在200℃时的吸附效率大于90%,并可持续50 min。SEM和FT-IR表征结果表明,在Co(NO_3)_2改性的活性炭表面和孔隙生成了Co_3O_4,促进NO催化氧化为NO_2并进行吸附。加热再生后的0.3 mol·L~(-1)Co(NO_3)_2改性活性炭对NO的吸附效率在60 min内仍高于88.90%,再生效果较好,可持续再生利用。     

酸碱改性及负载镍对活性炭脱硫性能影响研究

酸碱改性可增加活性炭表面官能团数量、增大比表面积和孔容、提高金属活性组分在其表面的分散度,负载镍可使活性炭具有较好的低温脱硫性能.为开发适合用于钢铁企业烧结烟气低温脱硫的活性炭,采用HNO3和KOH分别对椰壳活性炭进行改性并负载镍,分别开展HNO3改性活性炭的反应温度和改性条件对脱硫性能影响,通过BET对炭基和酸改性活性炭进行表征,KOH改性活性炭的碱炭比、活化时间和活化温度对脱硫性能影响,炭基、酸改性和碱改性活性炭且负载镍的脱硫剂脱硫性能研究.研究表明:60℃为1Ni/NAC最佳脱硫反应温度,HNO3处理后再负载镍对催化剂脱硫性能提高较大;合理的碱炭比为3:1,最佳活化时间为1 h,合适的活化温度为800℃;负载镍活性炭脱硫能力由强到弱的顺序为1Ni/NAC>1Ni/KAC>1Ni/AC.研究成果可为钢铁企业烧结烟气低温脱硫及多污染物协同治理提供借鉴.     

晋城无烟煤基活性炭吸附剂的制备及性能研究

以晋城无烟煤为原料,与KOH活化剂混合均匀,利用正交实验,通过碘吸附值和亚甲基蓝吸附值对其活化功率、活化时间和碱度等工艺条件进行探讨,采用扫描电镜(SEM)和BET比表面等检测手段,对KOH最佳工艺条件下制备的活性炭进行了表征.实验结果表明:KOH微波活化制备晋城无烟煤基活性炭的最佳工艺条件为活化功率480 W,活化时间7.5min,碱度4∶1,此时制备的活性炭吸附效果最好,其碘吸附值为989.4mg/g,比表面积为1 057.2m2/g,其工艺条件对活性炭吸附的影响递减顺序为:活化功率、活化时间、碱度.     

高比表面积活性炭(HSAAC)对水中Ni2+吸附性能的研究

以石油焦基为原料,采用KOH活化法制取高比表面积活性炭。考察了高比表面积活性炭吸附水中Ni(Ⅱ)时,PH值、Ni(Ⅱ)浓度、吸附时间和活性炭用量等因素对Ni(Ⅱ)吸附量和水中Ni(Ⅱ)残余浓度的影响。实验结果表明高比表面积活性炭在适宜条件下对Ni(Ⅱ)具有较大的吸附量和良好的再生效果。为HSAAC在废水中的实际应用提供了理论依据。     

利用稻草制浆黑液制备活性炭的研究

利用稻草制浆黑液中提取的木质素/二氧化硅复合材料为前驱体制备了活性炭.研究了活化剂KOH用量、活化反应的温度和活化反应的时间对活性炭吸附性能的影响.最佳的反应条件为:浸渍比(KOH于复合材料的质量比)为3:1,活化反应的温度为750℃,活化反应的时间为1h,此时制备的活性炭碘吸附值最大.制备的活性炭碘吸附值达到816.26 mg/g,BET比表面积为532.6 m2/g.活性炭大部分为介孔结构,含有少量微孔结构,平均孔径在6 nm.     

活化条件影响γ-Al2O3膜／污泥活性炭吸附脱硫机理

通过分析活化条件对γ-Al2O3膜/污泥活性炭表面孔结构和酸碱性的影响,研究了活化温度和活化时间对γ-Al2O3膜/污泥活性炭吸附脱硫性能影响的机理,探讨提高γ-Al2O3膜/污泥活性炭脱硫性能的活化条件.用BET(BRUNAUER-Emett-Teller)分别对γ-Al2O3膜/污泥活性炭的孔结构进行了研究,用化学法研究了γ-Al2O3膜/污泥活性炭表面的酸碱性.结果表明:随着活化温度升高,γ-Al2O3膜/污泥活性炭的BET比表面积增大,增强了物理吸附SO2气体的能力,超过600℃,γ-Al2O3膜/污泥活性炭的BET比表面积有所减少;碱性官能团的浓度随活化温度升高而显著地增加,有利于酸性气体SO2的化学吸附.随着活化时间的延长,γ-Al2O3膜/污泥活性炭的BET比表面积呈递减的变化趋势,碱性官能团呈现先增后减的变化趋势,使得吸附脱硫性能发生了相应的改变.     

氢氧化钾活化石油焦制备高比表面积活性炭

研究了以石油焦为原料,用氢氧化钾为活化剂制备高比表面积活性炭方法。通过正交实验与进一步的单因素实验考察了碱焦比、活化温度和活化时间对活性炭碘吸附值和活化收率的影响。实验结果表明碱焦比对活性炭碘吸附值影响最显著,增大碱焦比、延长活化时间和选择合适的活化温度能提高碘吸附能力。在碱焦比为4∶1,活化温度750℃和活化时间120 min条件下制备的活性炭BET比表面积可达2775 m2/g,总孔容为2.888 cm3/g。     

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%。     

H_2O_2/O_3催化氧化改性活性炭研究

采用H2O2/O3催化氧化改性活性炭。以含氧官能团总量为主要指标、比表面积和碘吸附值为辅助指标评价改性效果。在活性炭质量和H2O2体积一定的条件下,考察了H2O2质量分数、O3浓度、反应时间及反应温度等因素对活性炭性能的影响。在H2O2质量分数为10%、O3浓度为4.32 mg.L-1、反应时间为2.5 h、反应温度为50℃的最优改性条件下,活性炭的含氧官能团总量为1.525 mmol.g-1,比改性前提高61.38%。     

Surface modified granular activated carbon for enhancement of nickel adsorption from aqueous solution

Coal-based granular activated carbon was modified with acetates of sodium, potassium and lithium at concentrations of 10 and 15% and used as adsorbents to explore the adsorption mechanism of nickel ion in aqueous solution. Acetate treatment reduced surface area and pore volume of the activated carbons, but the adsorption amount of Ni(II) on the modified activated carbons (MAC) was greater than that on the virgin activated carbon. The adsorption depended on pH of the solution with an optimum at 4.5 and the adsorbed nickel could be fully desorbed by using 0.05M HCl solution. The maximum adsorption capacity of nickel ion on Li (15 wt%) modified activated carbon was 151.3 mg/g and the adsorption isotherm follows Langmuir, Sips, and Redlich-Peterson isotherm models better than the Freundlich isotherm model. The kinetic data was better fitted by a non-linear form of the pseudo-first order than the pseudo-second order, but the difference between two kinetic models was small.     

Preparation and electrocatalytic oxidation properties of a nickel pentacyanonitrosylferrate modified carbon composite electrode by two-step sol-gel technique: improvement of the catalytic activity

The sol-gel technique was used to construct nickel pentacyanonitrosylferrate (NiPCNF) modified composite ceramic carbon electrodes (CCEs). This involves two steps: forming a CCE containing Ni powder and then immersing the electrode into a sodium pentacyanonitrosyl-ferrate solution (electroless deposition). The cyclic voltammograms of the resulting surface modified CCE under optimum conditions show a well-defined redox couple due to the [Ni^IIFe^III/II(CN)₅NO]^0/−1 system. The electrochemical properties and stability of the modified electrode were investigated by cyclic voltammetry. The apparent electron transfer rate constant (k_s) and transfer coefficient (α) were determined by cyclic voltammetry being about 1.1 s⁻¹ and 0.55, respectively. Sulfite has been chosen as a model to elucidate the electrocatalytic ability of NiPCNF-modified CCE prepared by one- or two-step sol-gel technique. The modified electrode showed excellent electrocatalytic activity toward the SO₃²⁻ electro oxidation in pH range 3-9 in comparison with CCE modified by homogeneous mixture of graphite powder, Ni(NO₃)₂ and Na₂[Fe(CN)₅NO] (one-step sol-gel technique). Sulfite was determined amperometrically at the surface of this modified electrode in pH 7. Under the optimized conditions the calibration curve is linear in the concentration range 2 μM to 2.0 mM. The detection limit (signal-to-noise is 3) and sensitivity are 0.5 μM and 13.5 nA/μM. The modified carbon ceramic electrode containing nickel pentacyanonitrosylferrate shows good repeatability, short response time, t (90%) <2 s, long-term stability (3 months), and it is renewed by simple mechanical polishing and its immersing in Na₂[Fe(CN)₅NO] solution. The advantages of the SO₃²⁻ amperometrically detector based on the nickel pentacyanonitrosylferrate-doped CCE is high sensitivity, inherent stability at wide pH range, excellent catalytic activity and less expense and simplicity of preparation. This sensor can be used as amperometric detector in chromatographic instruments.     

K-, CeO2-, and Mn-promoted Ni/Al2O3 catalysts for stable CO2 reforming of methane

Reforming of methane with carbon dioxide into syngas over Ni/γ-Al₂O₃ catalysts modified by potassium, MnO and CeO₂ was studied. The catalysts were prepared by impregnation technique and were characterized by N₂ adsorption/desorption isotherm, BET surface area, pore volume, and BJH pore size distribution measurements, and by X-ray diffraction and scanning electron microscopy. The performance of these catalysts was evaluated by conducting the reforming reaction in a fixed bed reactor. The coke content of the catalysts was determined by oxidation conducted in a thermo-gravimetric analyzer. Incorporation of potassium and CeO₂ (or MnO) onto the catalyst significantly reduced the coke formation without significantly affecting the methane conversion and hydrogen yield. The stability and the lower amount of coking on promoted catalysts were attributed to partial coverage of the surface of nickel by patches of promoters and to their increased CO₂ adsorption, forming a surface reactive carbonate species. Addition of CeO₂ or MnO reduced the particle size of nickel, thus increasing Ni dispersion. For Ni–K/CeO₂–Al₂O₃ catalysts, the improved stability was further attributed to the oxidative properties of CeO₂. Results of the investigation suggest that stable Ni/Al₂O₃ catalysts for the carbon dioxide reforming of methane can be prepared by addition of both potassium and CeO₂ (or MnO) as promoters.     

负载壳聚糖的凹凸棒土对Ni~(2+)离子吸附性能的研究

天然凹凸棒土(AT)经盐酸和热处理制得活化凹凸棒土(MAT).以壳聚糖(CTS)改性MAT制得负载壳聚糖的凹凸棒土(CMAT)。用扫描电镜(SEM)和红外光谱(IR)对AT、MAT和CMAT的结构进行了表征。考察了Ni2+离子溶液的初始浓度、pH、吸附时间以及吸附温度对CMAT和CTS两种吸附剂吸附Ni2+离子性能的影响,得出了适宜的吸附条件。用IR对这两种吸附剂及其适宜条件下得到的吸附产物的结构进行了表征,并作了比较。结果表明,CMAT吸附Ni2+离子的适宜条件为:Ni2+离子溶液初始浓度40.0 mg/L,pH 4.03~6.04,吸附时间1.5 h,吸附温度25℃其最大吸附容量为15.2 mg/L;CTS吸附Ni2+离子的适宜条件为:Ni2+离子溶液初始浓度40.0 mg/L,pH3.00~4.12,吸附时间1.5 h,吸附温度35℃,其最大吸附容量为12.3 mg/L。在相同实验条件下,CMAT对Ni2+离子的吸附性能高于CTS,且二者的吸附行为均符合Langmuir吸附等温式。IR分析表明,CMAT对Ni2+离于的吸附包含化学吸附和物理吸附两个过程。而CTS主要是化学吸附。     

海泡石和稀土对镍催化剂性能的影响

本文研究了海泡石和稀土Sm镍催化剂的苯加氢活性及CO_２甲烷化活性的影响，并用XPS、活性比表面积及CS_２中毒等方法表征了催化剂的表面性质。结果表明，海泡石和稀土Sm能提高镍催化剂的加氢活性和抗毒性，并能增大活性镍的比表面及镍上的电子云密度，降低CO_２甲烷化反应的活化能。     

Electrocatalytic activity of Ni-doped nanoporous carbons in the electrooxidation of propargyl alcohol

Herein, we explore the immobilization of nickel on various carbon supports and their application as electrocatalysts for the oxidation of propargyl alcohol in alkaline medium. In comparison with massive and nanoparticulated nickel electrode systems, Ni-doped nanoporous carbons provided similar propargyl alcohol conversions for very low metallic contents. Nanoparticulated Ni on various carbon supports gave rise to the highest electrocatalytic activity in terms of product selectivity, with a clear dependence on Ni content. The results point to the importance of controlling the dispersion of the Ni phase within the carbon matrix for a full exploitation of the electroactive area of the metal. Additionally, a change in the mechanism of the propargyl alcohol electrooxidation was noted, which seems to be related to the physicochemical properties of the carbon support as well. Thus, the stereoselectivity of the electrooxidative reaction can be controlled by the active nickel content immobilized on the anode, with a preferential oxidation to (Z)-3-(2-propynoxy)-2-propenoic acid with high Ni-loading, and to propiolic acid with low loading of active Ni sites. Moreover, the formation of (E)-3-(2-propynoxy)-2-propenoic acid was discriminatory irrespective of the experimental conditions and Ni loadings on the carbon matrixes.     

Hydrogenation of naphthalene on NiMo- Ni- and Ru/Al2O3 catalysts: Langmuir–Hinshelwood kinetic modelling

The importance of the hydrodearomatisation (HDA) is increasing together with tightening legislation of fuel quality and exhaust emissions. The present study focuses on hydrogenation (HYD) kinetics of the model aromatic compound naphthalene, found in typical diesel fraction, in n-hexadecane over a NiMo (nickel molybdenum), Ni (nickel) and Ru (ruthenium) supported on trilobe alumina (Al₂O₃) catalysts. Kinetic reaction expressions based on the mechanistic Langmuir–Hinshelwood (L–H) model were derived and tested by regressing the experimental data that translated the effect of both naphthalene and hydrogen concentration at a constant temperature (523.15 and 573.15 K over the NiMo catalyst and at 373.15 K over the Ni and Ru/Al₂O₃ catalysts) on the initial reaction rate. The L–H equation, giving an adequate fit to the experimental data with physically meaningful parameters, suggested a competitive adsorption between hydrogen and naphthalene over the presulphided NiMo catalyst and a non-competitive adsorption between these two reactants over the prereduced Ni and Ru/Al₂O₃ catalysts. In addition, the adsorption constant values indicated that the prereduced Ru catalyst was a much more active catalyst towards naphthalene HYD than the prereduced Ni/Al₂O₃ or the presulphided NiMo/Al₂O₃ catalyst.     

改性吸附剂脱除燃油中二苯并噻吩的研究

采用浸渍法将5种金属离子Zn2+,Cu2+,Fe3+,Pb2+,Hg2+负载于活性炭和γ-氧化铝上,制备出一系列改性的吸附剂;用静态吸附法测定了燃料油中二苯并噻吩在不同吸附剂上的吸附等温曲线。结果表明,活性炭对97#汽油中二苯并噻吩吸附能力显著高于氧化铝;活性炭表面负载Zn2+,Cu2+,Fe3+,可以提高其对97#汽油中的二苯并噻吩的吸附量(摩尔质量浓度),其中负载Zn2+的活性炭吸附能力最大,硫饱和吸附量为478.3mmol/kg;γ-氧化铝上Pb2+的最佳负载质量分数为5.0%。