Methylene Blue Adsorption Value Research Articles

Bamboo charcoal derived high-performance activated carbon via microwave irradiation and KOH activation: application as hydrogen storage and super-capacitor

This paper attempts to prepare high-performance activated carbon (HP-AC) from bamboo charcoal (BC) as raw material using microwave irradiation as heating source and potassium hydroxide as activating agent. The influence of factors, such as activation time (3-15 min), KOH/C ratio (1:1-6:1) and particle size (0.147-2 mm) on its performance (the carbon yield and adsorptive capability) were investigated. The textural porosity and surface chemistry of HP-AC were determined by scanning electron microscope (SEM) analyzer, N 2 adsorption method and Fourier-transform infrared (FT-IR) spectrometer. The adsorptive properties of HP-AC were examined using iodine solution and methylene blue as model dye compound and hydrogen adsorbate. The effect of porosity and surface functionalities on the electrochemical capacitance of HP-AC were measured by cyclic voltammetry measurements. Under the best preparation conditions (activation time of 8 min, KOH/C ratio of 5:1 and particle size of 0.71-1.4 mm), the following results were obtained for the specific surface area, micro surface area, external surface area, total pore volume, iodine adsorption value, methylene blue adsorption value, carbon yield, hydrogen storage capacity and super capacitance value: 2,446 m 2 /g, 901 m 2 /g, 1,545 m 2 /g, 1.48 mL/g, 2,226 mg/g, 47.5 mL/0.1 g, 34.3%, 0.93 wt% (17.3 MPa, 25°C) and 3.63 wt% (1.0 MPa, -196°C), 212 F/g, respectively. The findings revealed the potential of BC as a raw material for the preparation of HP-AC, and to determine its potential applications of HP-AC as hydrogen storage and super-capacitor material.

Preparation and characterization of the hydrogen storage activated carbon from coffee shell by microwave irradiation and KOH activation

Coffee shell is an environmental concern to china along with steady growth of coffee production. This study attempt to characterize high specific surface area activated carbon (HSSA-AC). HSSA-AC was prepared from carbonized material which obtained from coffee shell by microwave irradiation. Textural properties and surface chemistry of HSSA-AC were found to be strongly depending on the activation time, KOH/C ratio and particle size. The textural properties of the samples were investigated by means of scanning electron microscope analyzer (SEM), cryogenic N2 adsorption, whereas, surface chemistry was probed through Fourier Transform Infrared (FTIR) spectrometer (Maldhure and Ekhe, 2011) and Hydrogen storage performance was tested by H2 adsorption. Maximum surface area of 3149 m2 g−1, Iodine adsorption value 2566 mg/g, Methylene Blue adsorption value 47.5 mL 0.1 g−1, the hydrogen adsorption value 0.91 wt% at 14 MPa and yield 39% was observed in case of microwave treated sample at activation time 9 min, KOH/C ratio 5 and particle size 0.25–0.71 mm. Results revealed usefulness of microwave treatment in influencing surface area of HSSA-AC which could be used in a hydrogen storage material research application.

Preparation and characterization of activated carbon & amorphous silica from rice husk

Activated carbon (AC) was prepared by the conventional carbonization and KOH activation and amorphous silica was extracted by alkali extraction followed by acid precipitation from rice husk on a laboratory scale. The performance of the produced activated carbon and amorphous silica were examined using I2 value measurement, methylene blue (MB) adsorption test, pH measurement, FTIR and SEM-EDX analysis. The optimum temperature for production of AC was obtained at 700 0C. The AC by alkali extraction method was show higher activity than KOH activation. The maximum I2 value, MB adsorption value & pH value shows at 700 0C followed by alkali extraction with 15% NaOH, which were 510.82 mg/g, 61.1 mg/g and 7.32 respectively. The FTIR analysis shows presence of Si-O-Si bond with a strong peak at 1078.28 cm-1. The SEM image of silica sample shows that the most of organic component is burnt out during combustion.Bangladesh J. Sci. Ind. Res. 50(4), 263-270, 2015

Preparation and Characterization of Microporous Activated Carbon from Raw Petroleum Cokes

Adopting the chemical activation method, the high specific surface area activated carbon (AC) was prepared by the solid mixing method using Daqing petroleum cokes as raw materials and KOH as activator. The influence of the ratio of KOH to carbon, activation temperature and activation time on the iodine and methylene blue adsorption properties of the AC were studied. The micro-graphitic structure of the AC was studied by X-ray diffraction (XRD). The BET specific surface area, BJH pore size distribution and pore volume of the AC were determined by N2 adsorption (at 77K). The experimental results show that the high specific surface area AC can be prepared with the ratio of KOH to carbon of 4, activation temperature of 800°C and activation time of 1h. The specific surface area was as high as 2142 m2/g with the iodine adsorption value of 288mg/g and methylene blue adsorption value of 1266mg/g. The XRD and BJH results also show that amorphous carbon was the dominating form, and the pore size distribution represents micropore structure.

Japanese cedar (Cryptomeria japonica) ash as a natural activating agent for preparing activated carbon

Japanese cedar (Cryptomeria japonica) ash was used as a natural activating agent and also a precursor to prepare activated carbon (AC) using various ash to water ratios (0.20, 0.25, and 0.33 wt%), activation temperatures (750, 850, and 950 °C), and activation durations (0.5, 1.0, and 1.5 h). The yields, iodine value, and methylene blue adsorption value of Japanese cedar AC were in the ranges of 27.3–30.7 %, 953.5–1150.9, and 695.1–1368.0 mg/g. As the ash to water ratio increased, the BET specific surface area and total pore volume of the AC increased. Japanese cedar AC prepared using an ash to water ratio of 0.33 wt%, an activation temperature of 850 °C, and an activation duration of 1.0 h exhibited the highest BET specific surface area (1430 m2/g) and total pore volume (0.74 cm3/g). The nitrogen adsorption–desorption isotherms of the Japanese cedar AC were classified as type IV, indicating the presence of microporous and mesoporous structures, according to the Bruauer, Deming, Deming, and Teller classification. Therefore, Japanese cedar ash with a suitable ash to water ratio can serve as an excellent natural activating agent for preparing AC because a high BET specific surface area can be obtained.

Urban Sludge and the Performance of the System of Wood Activated Carbon Research

In urban sludge and sawdust as raw material,using zinc chloride activation method in the preparation of activated carbon under different operating conditions, through the detection of specific surface area activated carbon sample and methylene blue adsorption value and the iodine adsorption value, studies the impregnation ratio, activation time and activation temperature operating conditions affect the performance of activated carbon sample. Through to the physical and chemical modification of activated carbon,To the preparation of activated carbon adsorption purification treatment experiment was carried out in the discharge of sewage.

Preparation, Surface and Pore Structure of High Surface Area Activated Carbon Fibers from Bamboo by Steam Activation.

High surface area activated carbon fibers (ACF) have been prepared from bamboo by steam activation after liquefaction and curing. The influences of activation temperature on the microstructure, surface area and porosity were investigated. The results showed that ACF from bamboo at 850 °C have the maximum iodine and methylene blue adsorption values. Aside from the graphitic carbon, phenolic and carbonyl groups were the predominant functions on the surface of activated carbon fiber from bamboo. The prepared ACF from bamboo were found to be mainly type I of isotherm, but the mesoporosity presented an increasing trend after 700 °C. The surface area and micropore volume of samples, which were determined by application of the Brunauer-Emmett-Teller (BET) and t-plot methods, were as high as 2024 m2/g and 0.569 cm3/g, respectively. It was also found that the higher activation temperature produced the more ordered microcrystalline structure of ACF from bamboo.

Adsorption of Cr Ion by Activated Carbon Prepared from Corncob Xylitol Residue

Corncob xylitol residue was soaked with H3PO4 for 16h and carbonized in microwave for 9min to obtain activated carbon. Methylene blue and iodine adsorption values were determined and were 119.92mg/g and 839.47mg/g, respectively. The adsorption property on Cr6+ was determined and the proper adsorption condition was pH2, 30min, 80°C. The maximum Cr adsorption capacity was 50mg/g.

Process optimization of K2C2O4-activated carbon from kenaf core using Box–Behnken design

Potassium oxalate was evaluated as a new activating agent for preparation of kenaf core-based activated carbons. The preparation conditions were optimized through Box–Behnken design (BBD) to maximize I2 and methylene blue (MB) adsorption values. Two quadratic models were developed to correlate the preparation variables namely activation temperature, impregnation ratio and activation time for both responses. The activated carbon produced at the optimum combination of process parameters showed 1161mg/g and 330mg/g of I2 and MB uptakes, which were in excellent agreement with the predicted values from the models. Porosity parameters and scanning electron microscopy were used to investigate the obtained optimal sample. The results reveal that K2C2O4 could be recommended as a promising effective activating agent for producing activated carbons from kenaf core with high surface area and potentially desirable dye removal capacity.

The comparison of two activation techniques to prepare activated carbon from corn cob

We report on the preparation of biomass-based activated carbons by the steam physical activation and KOH chemical activation methods. In addition, we also investigate their adsorption performance. By adjusting the reaction parameters, different carbon materials are prepared from corn residues and characterized using instrumental analyses such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Brunauer–Emmett–Teller (BET). It is found that the synthesized activated carbons exhibit high surface area (1600 m2 g−1) and large pore volume (2.01 cm3 g−1). Furthermore, the high methylene blue and iodine adsorption value and a considerable CO2 uptake (exceeding 1.5 mmol g−1) are attained with the activated carbons, showing their potential usage for the CO2 adsorbent.

PREPARATION OF PHOSPHORIC ACID ACTIVATED CARBON FROM SUGARCANE BAGASSE BY MECHANOCHEMICAL PROCESSING

Activated carbon was prepared from sugarcane bagasse with phosphoric acid activation by a mechanochemical process. The effects of milling time on adsorption properties and pore structure of activated carbon were evaluated. The results showed that phosphoric acid activation was assisted by the mechanochemical process, which can reduce the processing time and improve the adsorption performance of the prepared activated carbon. The iodine number, the methylene blue adsorption value, and the specific surface area of the prepared activated carbons were improved from 647.94 mg/g, 150 mg/g and 1075.21 m2/g to 889.37 mg/g, 177 mg/g and 1254.52 m2/g, respectively. Compared with conventional phosphoric acid activation, the activated carbon produced by the mechanochemical process achieved the advantages of shorter processing time, greater adsorption capacity, and higher adsorbed amounts of iodine, methylene blue, and nitrogen.

Absorption Performance of Activated Carbon with Orange Peel through Phosphoric Acid Activation Method

In order to reduce power plant nitric oxide emission with gaining economical adsorbent, activated carbon was prepared from the raw materials of orange peel under different operating conditions in this paper. The methylene blue adsorption value of different activated carbon has also been tested, and the effects on the methylene blue adsorption performance of different dipping concentration, activation time and carbonization temperature were studied. The finding is that the dipping concentration has the most important impact on methylene blue adsorption value. The highest methylene blue adsorption value of orange peel activated carbon has shown as 277.746mg/g under the following conditions: phosphoric acid concentration was 40%, activation time was 12 hours and carbonization temperature was 500°C. It is a economically feasible absorbent material through a great deal of experiments and analysis.

Experimental Design To Optimize the Preparation of Activated Carbons from Herb Residues by Vacuum and Traditional ZnCl2 Chemical Activation

Doehlert matrix was used to optimize the experimental conditions for the preparation of activated carbons from herb residues by vacuum chemical activation and traditional chemical activation using ZnCl2 as activation agent. The effects of activation temperature and impregnation ratio, the most influential factors of ZnCl2 chemical activation, were studied. The obtained activated carbons were characterized by total yield and methylene blue and iodine adsorption value. Each response has been described by a second-order model, and the predicted model presented a good agreement with experimental data. The results showed that activated carbons prepared by vacuum chemical activation have higher yield and better adsorption capacity. The removal percentages of methylene blue for the two optimal activated carbons and a commercial activated carbon were determined. The activated carbon prepared by vacuum chemical activation exhibited the highest methylene blue removal efficiency.

Preparation of high-surface-area activated carbon from coconut shell fibers

Activated carbons (ACs) with high specific surface area and abundant mesopores were prepared from coconut shell fibers through carbonization and NaOH/KOH activation. The influence of NaOH/KOH ratio,carbonization temperature,activation temperature,activation time and heating rate on the adsorption behavior of the ACs were investigated. The specific surface area of the obtained ACs under optimum conditions was 2 032 m2/g with 28% (volume fraction) of mesopores between 2 to 4 nm. The iodine adsorption value and methylene blue adsorption value of the AC were 1 435 and 495 mg/g,respectively.

Characteristics of activated carbon prepared from Chinese fir sawdust by zinc chloride activation under vacuum condition

The preparation of activated carbon from Chinese fir sawdust by zinc chloride activation under both nitrogen atmosphere and vacuum conditions was carried out in a self-manufactured vacuum pyrolysis reactor. The effects of the system pressure and the activation condition (nitrogen or vacuum) on pore development were investigated. The results show that both high quality activated carbon and high added-value bio-oil can be obtained simultaneously via vacuum chemical activation. The characteristics of the activated carbons produced under vacuum conditions are better than those prepared under nitrogen atmosphere. The performance parameters of the activated carbon obtained under vacuum conditions are as follows: the pore size distribution is mainly microporous, the Brunauer-Emmett-Teller (BET) surface area is 1 070.59 m2/g, the microporous volume is 0.502 4 cm3/g, the average pore size is 2.085 nm, and the iodine adsorption value and the methylene blue adsorption value are 1 142.92 and 131.34 mg/g, respectively. The activated carbon from vacuum chemical activation has developed micropores, and the N2 adsorption equilibrium constant of the corresponding activated carbon gradually increases with the decrease of reaction system pressure.

A comparative study on the performance of sands rich and poor in fines in self-compacting concrete

Self-compacting concrete (SCC) as a special concrete, has practical advantages due to its mechanical performance and application easiness. However, a more careful study is needed at the stage of mixture proportioning. In order to produce SCC, a more voluminous but also a more viscous matrix is needed compared to concrete of normal workability. This may be achieved by using additional fillers with pozzolanic or inert nature. The employment of sands rich in fines may be a second alternative source of filler. However, the physical properties of sands rich in fines affect the performance of SCC in dual ways. In this study, the effects of the changes in the physical properties of sands (in particular the fine material content and type), on concrete performance were investigated. SCC mixtures containing four different sands (washed natural (WN) sand, washed crushed limestone (WCL) sand, crushed limestone sand with silt powder (CLS) and crushed limestone sand with clay powder (CLC)) were produced and the admixture requirements for each type of SCCs were determined. Test results suggest that, in order to produce SCC with the same consistency, admixture requirement may change with the physical properties of sands used. When compared to SCCs prepared with washed sand (poor in fines), approximately similar compressive strengths have been obtained by using CLS sand. On the other hand, CLC sand caused strength loss and increased the admixture demand for a targeted slump-flow of SCC. Due to the increased admixture content, setting times of SCCs prepared with CLC sand were also lengthened. The methylene blue adsorption value is a good indicator of clay content of sand. This test method was efficiently used for the selection of appropriate sand type incorporating high volumes of fine materials. Additionally, microstructural studies revealed some clues about the poor performance of SCCs prepared with CLC sand.

Physical and chemical characteristics of polymer-based spherical activated carbon and its ability to adsorb organics

The characterization of a polymeric spherical activated carbon (PAC) was performed by comparing its adsorption, porosity, functional groups and some of the physical properties with a commercial spherical activated carbon (CAC). The PAC was about 4 times superior to the CAC with respect to the mechanical strength. The micropore volume of the PAC was about 5% smaller than that of the CAC. The maximum methylene blue adsorption values of the PAC and the CAC were 32 and 14 mgg−1, respectively, which indicated low mesopore volumes as consistent with the values of BJH volume. This resulted in the low butane working capacity values for both activated carbons. Adsorption parameters for the Langmuir and the Freundlich isotherm models were determined for all organic substances tested. Both isotherms were suitable models to analyze the equilibrium data for the removal of all organics. However, the Langmuir model fitted better than the Freundlich model and the adsorption capacities of the PAC were somewhat higher than those of the CAC. The chemical properties of the activated carbons, the pH of solutions and the substituents on absorbates have an effect on adsorption of the organics tested.

Hydrothermal Synthesis of Novel Smectite-Like Mesoporous Materials

Hydrothermal reaction of slurries made from Si-Mg hydrous oxide and water yielded trioctahedral smectite-like mesoporous materials (SMMs). The OH anion had a marked effect on the properties of SMMs under hydrothermal condition whereas Na cation did not influence SMMs properties. With the increase in synthesis pH at 200°C, pore volume, specific surface area and average pore diameter decreased whereas methylene blue adsorption increased in the pH range of 8.5 to 11.4. Therefore, the SMMs having different layer charges could be synthesized. Both micropore and macropore formation rates decreased with increasing synthesis temperature in the range of 125–200°C and the formation of latter increased over 200°C. As a result, the SMMs synthesized at 200°C from slurries of pH 9.0–9.3 revealed the maximum mesopore formation rate: 0.98 and gave a narrow pore size distribution curve of 3–5 nm. The SMMs were characterized by specific surface areas of 243–679 m2 g-1, pore volumes of 0.20–0.48 cm3 g-1, average pore diameters of 2.2–5.4 nm and methylene blue adsorption values of 0.16–0.96 meq · g-1.

Methylene Blue Adsorption as a Rapid and Economical Method of Detecting Smectite

Abstract Methylene blue adsorption (MBA) is found to be an effective method of indicating when smectite (group name for the mont-morillonite minerals) is present in major amounts in mudrocks or along discontinuities. The basic relationship is that MBA values greater than 15 indicate that smectite is present as 15 is the maximum value found for illite, the next most adsorptive mineral as compared with smectite. For example, the Pierre shale, which typically contains 30 to 40% smectite along with 25 to 45% mixed-layered smectite-illite has a MBA value of 48.5; whereas, the Palastine shale, which has illite rather than smectite as its chief component has a MBA value of only 7.0. The abundant smectite constituted samples are of materials involved either in slope stability or slaking in foundations, or both. MBA requires only a 2-g specimen, and thus clays along discontinuities and clays along thin slip zones of slides can also be analyzed as to type of clay. The method is less expensive than X-ray diffraction analyzes but also can supplement X-ray diffraction investigations.