磷酸法茶渣活性炭的制备及吸附性能

以牡丹花茶饮料生产末端茶渣(以下简称"茶渣")作为活性炭制备原料,考察磷酸与茶渣的浸渍比、活化温度、活化时间对活性炭得率、碘吸附值的影响。结果表明,磷酸法制备茶渣活性炭的最佳工艺参数为:浸渍比(磷酸/原料)为1∶2.5,活化温度550℃,活化时间0.5 h。活性炭得率为29.91%,碘吸附值为968.75 mg/g。含水率为4.80%,灰分含量为17.25%。接近于国家一级活性炭对碘吸附值的要求标准1 000 mg/g。100 mL浓度为10 mg/L的苯酚废水,加入0.1 g活性炭,25℃振荡1 h,pH=5时,茶渣活性炭对于苯酚吸附量达到8.67 mg/g,吸附率约为87%。     

磷酸法茶渣活性炭的制备及吸附性能

以牡丹花茶饮料生产末端茶渣(以下简称"茶渣")作为活性炭制备原料,考察磷酸与茶渣的浸渍比、活化温度、活化时间对活性炭得率、碘吸附值的影响。结果表明,磷酸法制备茶渣活性炭的最佳工艺参数为:浸渍比(磷酸/原料)为1∶2.5,活化温度550℃,活化时间0.5 h。活性炭得率为29.91%,碘吸附值为968.75 mg/g。含水率为4.80%,灰分含量为17.25%。接近于国家一级活性炭对碘吸附值的要求标准1 000 mg/g。100 mL浓度为10 mg/L的苯酚废水,加入0.1 g活性炭,25℃振荡1 h,pH=5时,茶渣活性炭对于苯酚吸附量达到8.67 mg/g,吸附率约为87%。     

水蒸气活化法制备稻壳活性炭的研究

研究了水蒸气活化法制备稻壳活性炭的工艺条件,探讨了炭化温度、活化温度、活化时间和水蒸气用量对活化效果的影响。最佳工艺条件为:炭化温度 450℃、活化温度 900℃、活化时间 90 min和水蒸气用量为炭化料的1.5倍,制备的活性炭碘吸附值 844 mg/g,亚甲基蓝吸附值 138 mL/g,产品得率 13.9%。这些指标与木质活性炭相当。且投资少,能耗低,具有良好的经济效益与社会效益。     

利用废弃机制炭颗粒制备活性炭研究

以机制炭废弃炭颗粒为原料,水蒸汽法物理活化制备吸附性能较佳且得率较高的活性炭。通过正交试验设计,研究活化温度、活化时间和水蒸气用量对活性炭吸附性能、活化得率和固定碳含量的影响。得到最佳活化工艺条件为:活化时间1.5h、活化温度950℃、水蒸汽用量700-750g/h。制得活性炭的碘吸附值1162mg/g,亚甲基蓝吸附值9.5ml/0.1g,活化得率36.67%。     

用褐煤活化一步法制备活性炭的研究

介绍了以褐煤为原料,磷酸为活化剂,硫酸为添加剂,采用炭活化一步法制备活性炭的实验,讨论了浸渍温度、炭活化温度、炭活化时间、磷酸的浓度、磷酸溶液与褐煤的液固比、硫酸的用量等主要因素对活性炭性能的影响。结果表明,适宜的工艺条件为:浸渍温度为80℃,炭活化温度为400℃,炭活化时间为60min,磷酸质量分数为40%,磷酸溶液与褐煤的液固比为5:1,硫酸的用量为褐煤质量6%。在该适宜的工艺条件下制备的活性炭,强度为88.2%,比表面积为1 158.6 m2/g,吸碘值为946.5 mg/g,吸亚甲基蓝值为203.4mg/g。     

水稻秸秆制备活性炭吸附剂工艺研究

以水稻秸秆为原料、氢氧化钠为活化剂制备活性炭。结果表明水稻秸杆活性炭的最佳工艺条件:碱碳比为2∶1,活化时间为60 min,活化温度为600℃,碳化温度为350℃,在此工艺条件下制备的水稻秸秆活性炭的亚甲基蓝吸附值和碘吸附值分别为29.2 mL/0.1 g和1 706.98 mg/g,制备出的活性炭吸附剂质量指标接近水质净化用活性炭标准。     

光合竹制备活性炭吸附剂的工艺探讨

以光合竹为原料,研究了其制备活性炭的工艺条件,考察了活化剂浓度、固液比、活化时间以及活化温度等因素对活性炭碘吸附值、亚甲基蓝吸附值的影响。实验结果表明,用化学法制备光合竹活性炭的最佳工艺参数为:以Zn Cl2为活化剂,Zn Cl2浓度为5 mol/L,活化剂浸渍时间为2 h,固液比为1∶4,活化时间为60 min,活化温度为500℃。在此工艺条件下所制备活性炭得率为48.8%,亚甲基蓝吸附值为197.14 mg/g,碘吸附值为1 034.30 mg/g,样品质量指标接近净化用活性炭标准。     

碳酸钾法制备茶渣活性炭工艺优化及吸附性能

以牡丹花茶饮料生产末端残渣(以下简称"茶渣")为原料,以2 mol/L碳酸钾溶液为活化剂,制备茶渣活性炭。研究了剂料比、活化温度、活化时间对茶渣活性炭吸附性能的影响。结果表明,碳酸钾法制备残渣活性炭的最佳工艺参数为:碳酸钾/茶渣剂料比1∶1.5(质量比)、活化温度500℃、活化时间1 h,所得活性炭水分、灰分、得率、碘吸附值分别为4.67%,3.10%,9.89%,931.93 mg/g。接近于国家一级活性炭对碘吸附值的要求标准1 000 mg/g。pH=5时,茶渣活性炭对于苯酚最大吸附量和吸附率分别达到9.35 mg/g,吸附率94%。     

碳酸钾法制备茶渣活性炭工艺优化及吸附性能

以牡丹花茶饮料生产末端残渣(以下简称"茶渣")为原料,以2 mol/L碳酸钾溶液为活化剂,制备茶渣活性炭。研究了剂料比、活化温度、活化时间对茶渣活性炭吸附性能的影响。结果表明,碳酸钾法制备残渣活性炭的最佳工艺参数为:碳酸钾/茶渣剂料比1∶1.5(质量比)、活化温度500℃、活化时间1 h,所得活性炭水分、灰分、得率、碘吸附值分别为4.67%,3.10%,9.89%,931.93 mg/g。接近于国家一级活性炭对碘吸附值的要求标准1 000 mg/g。pH=5时,茶渣活性炭对于苯酚最大吸附量和吸附率分别达到9.35 mg/g,吸附率94%。     

稻壳炭脱硅制活性炭及吸附性能研究

研究稻壳炭脱硅工艺,探究氯化锌法和磷酸法活化脱硅稻壳炭工艺。结果表明,通过热碱溶解回流有很好的脱硅效果。磷酸活化法制备稻壳活性炭相对氯化锌活化法而言,得率较高,在浸渍比为2∶1,浓硫酸添加量为1%,预处理温度240℃,预处理时间1 h,活化温度500℃的实验条件下制得的活性炭,亚甲基蓝吸附值66 mg/g,碘吸附值679 mg/g。实验表明该工艺制得的活性炭不仅吸附性能较好且产量高,在工业应用上具有很好的经济价值。     

Carbonization and CO<Subscript>2</Subscript> activation of scrap tires: Optimization of specific surface area by the Taguchi method

This research demonstrates the production of activated carbon from scrap tires via physical activation with carbon dioxide. A newly constructed apparatus was utilized for uninterrupted carbonization and activation processes. Taguchi experimental design (L16) was applied to conduct the experiments at different levels by altering six operating parameters. Carbonization temperature (550–700 °C), activation temperature (800–950 °C), process duration (30–120 min), CO₂ flow rate (400 and 600 cc/min) and heating rate (5 and 10 °C/min) were the variables examined in this study. The effect of parameters on the specific surface area (SSA) of activated carbon was studied, and the influential parameters were identified employing analysis of variance (ANOVA). The optimum conditions for maximum SSA were: carbonization temperature=650 °C, carbonization time=60 min, heating rate=5 °C/min, activation temperature= 900 °C, activation time=60 min and CO₂ flow rate=400 cc/min. The most effective parameter was activation temperature with an estimated impact of 49%. The activated carbon produced under optimum conditions was characterized by pore and surface structure analysis, iodine adsorption test, ash content, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The process yield for optimized activated carbon was 13.2% with the following properties: specific surface area=437 m²/g, total pore volume=0.353 cc/g, iodine number=404.7 mg/g and ash content=13.9% along with an amorphous structure and a lot of oxygen functional groups. These properties are comparable to those of commercial activated carbons.     

Porous properties of activated carbon produced from Eucalyptus and Wattle wood by carbon dioxide activation

This work focused on the preparation of activated carbon from eucalyptus and wattle wood by physical activation with CO₂. The preparation process consisted of carbonization of the wood samples under the flow of N₂ at 400°C and 60 min followed by activating the derived chars with CO₂. The activation temperature was varied from 600 to 900°C and activation time from 60 to 300 min, giving char burn-off in the range of 20/2-83%. The effect of CO₂ concentration during activation was also studied. The porous properties of the resultant activated carbons were characterized based on the analysis of N2 adsorption isotherms at −196°C. Experimental results showed that surface area, micropore volume and total pore volume of the activated carbon increased with the increase in activation time and temperature with temperature exerting the larger effect. The activated carbons produced from eucalyptus and wattle wood had the BET surface area ranging from 460 to 1,490 m²/g and 430 to 1,030 m²/g, respectively. The optimum activation conditions that gave the maximum in surface area and total pore volume occurred at 900°C and 60 min for eucalyptus and 800°C and 300 min for wattle wood. Under the conditions tested, the obtained activated carbons were dominated with micropore structure (∼80% of total pore volume).     

Diuron Multilayer Adsorption on Activated Carbon from CO2 Activation of Grape Seeds

Granular activated carbons were obtained from grape seeds by pyrolysis at 600°C and subsequent physical activation with CO₂ (750–900°C, 1–3 h, 25–74% burn-off). The carbon and ash content increased during the activation, reaching values of 79.0% and 11.4%, respectively. Essentially microporous materials with BET surface areas between 380 and 714 m²/g were obtained. The performance of the activated carbon in the adsorption of diuron in aqueous phase was studied within the 15–45°C temperature range. Equilibrium data showed that the maximum uptake increased with temperature from 120 to 470 µmol/g, also evidencing some dependence of the adsorption mechanism on temperature. Data were fitted to five isotherm models [Langmuir, Freundlich, Dubinin–Radushkevich, BET, and GAB (Guggenheim, Anderson, and de Boer)]. Kinetic data were analyzed using first- and second-order rate equations and intraparticle diffusion model. The second-order rate constant values obtained (2.8–13.5 × 10^?3 g/µmol min) showed that the hollow core morphology of the material favors the adsorption kinetics.     

Adsorption of chromium(VI) and nickel(II) ions on acid- and heat-activated deoiled spent bleaching clay

De-oiled spent bleaching clay was activated either by acid treatment followed by heat activation or by heat activation alone at temperatures between 200 and 800°C. The surface area of the heat-activated clay attained a maximal value of ≈120 m² g⁻¹ at temperatures between 400 and 500°C while the acid-heat-treated clay attained maximal surface area of ≈140 m² g⁻¹. The adsorption capacities of chromium [Cr(VI)] for both series studied increased as the activation temperature increased until 300°C and decreased again at higher temperatures. At lower pH, more than 95% of the Cr(VI) was absorbed in a solution with initial concentration of 1 mg L⁻¹ per gram of adsorbent activated at 300°C. The adsorption patterns followed Freudlich's isotherms. Two maximal values of adsorption capacities of nickel [Ni(II)] were observed at activation temperatures of 200 and 500°C for acid-treated samples, whereas these were at 200 and 700°C for the nonacid-treated samples. The amount of Ni(II) adsorbed increased with the pH of the solution for all samples studied. The maximal adsorption capacities of the adsorbents in solution containing initial Ni(II) concentration of 5 mg L⁻¹ per 0.5 g of adsorbent and at pH 6 were found to be 44 and 42%, respectively, for the acid-treated sample activated at 500°C and for the nonacid-treated sample activated at 700°C. They all obeyed both the Langmuir's and Freundlich's isotherms.     

Preparation and Characterization of Activated Carbon from Chestnut Shell and its Adsorption Characteristics for Lead

Activated carbons were prepared from chestnut shell by phosphoric acid activation and the prepared activated carbons were used to remove lead(II) from aqueous solutions. The effects of impregnation ratio (IR) and activation temperature on activated carbon production were investigated. The produced activated carbons were characterized by N₂ adsorption, scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques. The highest surface area (1611 m²/g) and total pore volume (0.7819 cm³/g) were obtained at a carbonization temperature of 500°C with an impregnation ratio of 3/1. The resulting activated carbon was used for removal of lead(II) from aqueous solution. The effects of temperature, contact time, and adsorbent dosage were investigated. The adsorption isotherm studies were carried out and the obtained data were analyzed by the Langmuir, Freundlich, and Temkin equations. The rate of adsorption was found to conform to the pseudo-second-order kinetic model. The Langmuir isotherm equation showed better fit for all temperatures and the maximum adsorption capacities of lead(II) was obtained as 138.88 mg/g at 45°C.     

Adsorptive Removal of Rhodamine B with Activated Carbon Obtained from Okra Wastes

This study aimed at preparing and optimizing an activated carbon (OAC) obtained from dry okra wastes by chemical activation with zinc chloride. Also, Rhodamine B removal performance from aqueous solution was analyzed by using this optimized activated carbon. The characterization of the resultant activated carbon, with a high surface area of 1044?m²/g, was carried out using thermogravimetric analysis, Brunauer–Emmett–Teller model, t-plot, N₂ adsorption/desorption isotherms, density functional theory, elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and the point of zero charge. Furthermore, the effects of operating conditions (contact time, initial concentration, adsorbent dosage, temperature, and pH) on Rhodamine B adsorption onto OAC were investigated. Langmuir model was determined to be the best adsorption process, and the maximum adsorption capacity was calculated to be 321.50?mg/g at 25°C. Also, the intraparticle diffusion and boundary layer diffusion were involved in RhB adsorption onto OAC. Moreover, OAC adsorption curves of Rhodamine B followed pseudo second-order model. At 25°C, Gibbs free energy, enthalpy, and entropy obtained from thermodynamic studies were determined to be ?27.87?kJ/mol, 13.03?kJ/mol, and 0.15?kJ/mol K, respectively. These thermodynamic values revealed that Rhodamine B adsorption onto OAC was feasible, endothermic, physical, and spontaneous.     

原料复配制备木质素基成型活性炭研究

以碱木质素和杉木屑为原料,磷酸为活化剂,制备碱木质素基成型活性炭,考察了碱木质素质量分数、浸渍比、活化温度、活化时间等对活性炭性能的影响。研究结果表明：碱木质素复配杉木屑（碱木质素质量分数50%）后,复配料的表面润湿性显著提高,瞬时水接触角由133.2°（碱木质素）降低至86.6°（复配料）;热膨胀系数显著降低,膨胀温度区间的热膨胀系数由2 365 μm/（m·℃）（碱木质素）降低至45 μm/（m·℃）（复配料）。在最佳工艺条件即碱木质素质量分数50%、浸渍比1.5：1（纯磷酸与复配料质量比）、活化温度500℃、活化时间90 min下,制备的成型活性炭得率41.76%,碘吸附值1 070 mg/g,亚甲基蓝吸附值255 mg/g,强度90%,比表面积1 646 m²/g,总孔容积为0.795 cm³/g,其中孔径小于5 nm的孔容积占总孔容积的97.2%。     

Preparation of High Surface Area Mesoporous Activated Carbon: Kinetics and Equilibrium Isotherm

Activated carbon prepared from palm shell by phosphoric acid impregnation, at significantly favorable experimental conditions is characterized for the porous nature and adsorption of methylene blue dye molecules. The activation is carried out using a 2-stage activation process with the activation in a self-generated atmosphere. An activation temperature of 500°C, with an activation time of 75 minutes using a phosphoric acid impregnation ratio of 3 has yielded an activated carbon having unique characteristics. An activated carbon with a yield of 48%, total pore volume of 1.9 cm³/g, surface area of 1956 m²/g, an average pore diameter of 3.8 nm, with the ratio of the mesopore to the total surface area in excess of 75% has been prepared. The activated carbon exhibits a high methylene blue equilibrium adsorption capacity of 438 mg/g with the adsorption isotherm increasing with an increase in the adsorption temperature. Among the various adsorption isotherm models, the Langmuir model is able to explain the adsorption process well, evidenced by the proximity of the model with the experimental data. Among the different kinetic models tested with the experimental kinetic data, a pseudo-second-order model is found to fit the experimental data with close proximity.     

Carbon dioxide activated carbide-derived carbon monoliths as high performance adsorbents

Carbide-derived carbon (CDC) monoliths (DUT-38) with a distinctive macropore network are physically activated using carbon dioxide as oxidizing agent. This procedure is carried out in a temperature range between 850 and 975 °C with durations ranging from 2 to 6 h. Resulting materials show significantly increased specific surface areas as high as 3100 m²/g and total (micro/meso) pore volumes of more than 1.9 cm³/g. The methane (214 mg/g at 80 bar/25 °C), hydrogen (55.6 mg/g at 40 bar/−196 °C), and n-butane (860 mg/g at 77 vol.%/25 °C) storage capacities of the activated CDCs are significantly higher as compared to the non-activated reference material. Moreover, carbon dioxide activation is a suitable method for the removal of metal chlorides and chlorine residuals adsorbed in the pores of CDC after high temperature chlorination. The activation does not influence the hydrophobic surface properties of the CDCs as determined by water adsorption experiments. The macropore network and the monolithic shape of the starting materials can be fully preserved during the activation procedure. n-Butane breakthrough studies demonstrate the materials applicability as an efficient hydrophobic filter material by combining excellent materials transport with some of the highest capacity values that have ever been reported for CDCs.     

Microstructure characterization and compressive performance of 3D needle-punched C/C–SiC composites fabricated by gaseous silicon infiltration

3D needle-punched C/C-SiC composites were fabricated from carbon fiber reinforced carbon (C/C) preforms, with densities of 1.05?g/cm³ and 1.28?g/cm³, by the gaseous silicon infiltration (GSI) method at fabrication temperatures from 1500?°C to 1800?°C. The compressive strengths and elastic moduli in transverse direction are larger than those measured under longitudinal compression except that samples fabricated from 1.28?g/cm³ density exhibit lower elastic moduli in transverse direction than in longitudinal direction. The compressive strength and modulus increase with fabrication temperature at 1500?°C and 1600?°C, and then decrease with higher fabrication temperature. Samples fabricated from the lower density C/C preforms have greater compressive strength and modulus. X-ray tomography was applied before and after the mechanical tests to characterize the microstructure and damage patterns, and the results indicated that for C/C-SiC composites fabricated at 1700?°C from 1.28?g/cm³ density C/C preform the matrix has a volume fraction (vol%) of 36.9%, and the initial intra-bundle cracks (0.6?vol%) display a space crossing structure while the inter-bundle pores (6.0?vol%) are special irregularly distributed.