Methylene Blue Value Research Articles

Experimental study of methylene blue adsorption from aqueous solutions onto Fe3O4/NiO nano mixed oxides prepared by ultrasonic assisted co-precipitation

According to the increasing development of the mankind, social and technology activities in the earth, various industry is in a state of uncontrolled growth. In the present study, magnetite/nickel oxide mixed metal oxide nanoparticles (FNMMO NPs) were prepared by a simple method assisted by ultrasonic waves and applied as a novel adsorbent to dispose of dye wastewater. The morphology and chemical structures of the Fe3O4, NiO and FNMMO NPs were characterization by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), energy-dispersive X-ray spectroscopy (EDX), scanning electronic microscope (SEM) and transmission electron microscope (TEM). The adsorption of methylene blue (MB) onto FNMMO NPs was studied in relation to initial concentration of MB, contact time, adsorbent dose and pH value of solution. The equilibrium adsorption isotherm was fitted by Langmuir isotherm. The capacity of adsorption was evaluated 40.1 mg.g-1 and the time required to reach the adsorption equilibrium was 180 min.

Revisiting Relationships among Specific Surface Area, Soil Consistency Limits, and Group Index of Clays

Abstract Investigations correlating specific surface area (SSA) with other soil parameters like consistency limits are helpful in understanding the internal meaning of soil properties. In this study, a large database (267 groups of test results) from the literature is established, and the performed statistical analyses show that the traditional relationship with limited data may be invalid when large data are involved. Hereafter, there is a relatively good relationship between the soil consistency limits and SSA when the threshold SSA value (about 80 m2/g) is identified, which suggests that the soils totally behave as pellets and platelets in the geometry, respectively, before and after this value. Despite the fact that this threshold SSA should complicatedly depend on the crystalline formation, clay mineral, and clay fraction in the particle size distribution, this threshold is relatively reliable in view of these large data statistics. Additionally, the group index by ASTM and the methylene blue value by Laboratoire Centrale des Ponts et Chaussées in France can be mutually converted to characterize subgrade soils to account for the established relationship between consistency limits and SSA.

Physical, thermal and mechanical properties of adobes stabilized with fonio (Digitaria exilis) straw

This study deals with the influence of fonio straw on the physical, thermal and mechanical properties of adobes. The raw materials (soil and fonio straw from Burkina Faso) were characterized from the chemical (ICP-AES), mineralogical (XRD, DSC-TGA, IR), geotechnical (particle size distribution, Atterberg limits, methylene blue value) and microstructural (SEM-EDS) points of view. The physical (thermal conductivity, capillarity water absorption, porosity, erodibility) and mechanical (compressive and flexural strength) properties of the adobes were studied with specific attention paid to their damage and fracture behavior. Because of the biochemical composition of fonio straw (presence of quasi-crystalline cellulose and hemicelluloses, which are hydrophilic compounds), its association with the clay matrix increased water absorption and was accompanied by a significant porosity due to the air trapped during mixing. The insulating character of the cellulose and the low density resulting from the high porosity contributed to an appreciable reduction of the thermal conductivity of these adobes. The use of small amounts of fonio straw improved the mechanical properties of the adobes and made them less brittle. This improvement was linked to the good adhesion between fonio straw and the clay matrix, greatly reduced propagation of fissures in the composites and the high tensile strength of fonio straw because of its cellulose content. Thus, fonio-straw-reinforced adobes have interesting properties for use as cheap construction materials in the Sahelian zones and could contribute significantly to the thermal comfort of the inhabitants in this hot climate.

Fines quality assessment in all-in aggregates for pavement layers related to different standard procedures

During the construction of the unbound pavement layers of Corridors X and XI in Serbia, a problem was detected regarding the evaluation of cleanliness of the available materials. The European standard for the sand equivalent from 1999 to 2015 had significant changes related to the test procedure. A mass correction has been taken into account. It consists of replacing a part of the fines with rinsed material (0.063/2 mm) when the percentage of fines exceeds 10% in a tested fraction. Thus, the test sample usually yields high values of the sand equivalent, which often exceeds the limits of 50% and 60%. From the standpoint of the technical specifications, aggregates are considered clean, while using other methods like methylene blue or a plasticity index, the presence of clay particles above the limits can be confirmed. This paper presents the results of research on 63 laboratory-prepared test samples of limestone aggregate with small quantities of the smectite group of clay minerals, where the fines content in the unbound aggregate, 0/31.5 mm, gradually increased up to 20%. It was found that the sand equivalent values are continuously decreasing from 84 to 14% in the fraction 0/2 mm and from 87 to 18% in the 0/4 mm fraction, with increasing of the methylene blue value of the all-in aggregate (MBA) from 0.4 to 4.5 g/kg. Correlations of different methods and fractions, as well as with the content of fines were found. There are no correlations with SE10 because of grouping the test data around one point.

Investigations of the Crushed Basanite Aggregates Effects on Lateritic Fine Soils of Bafang Area (West-Cameroon)

The gravelly lateritic soils are commonly used for road sub-grade and sub-base course in tropical region due to their good bearing capacity. Whereas, the lack of their ore deposit along or near the corridors of the road construction implies the development of new approach for using these local materials in road construction works. That is why, this study has focused on blending of fine tropical soils with 0/5 mm of crushed basanite to be used for realizing the sub-base course layer. To achieve this aim, mineralogical, chemical and geotechnical tests were performed on crushed basanite and natural fine lateritic soils; and on the mixing materials at 20%, 30%, 40% and 50% of crushed basanite on the other hand. The mineralogical and chemical investigation on two facies of natural fine lateritic soils revealed that Silica/Sesquioxide ratios are less than 2 (S/R < 2). With the increasing of the rate of crushed basanite on these natural fine soils, basanite minerals increase in the mixing materials, but the S/R ratios are still less than 2. Moreover, this implies the relative increase of chemical elements in general and the increase of the amount of Ca, Mg, Na, K, Mn elements in particular. Despite the Ca element increases with the rate of mixing, chemical reaction is not implied. Even more, the addition of crushed basanite on fine lateritic soils have positive effects because fine particles, liquid limit, plasticity index, methylene blue values and optimum moisture content decrease, but conserve their geotechnical class or group, according to geotechnical classification standard. However, the maximum dry density, the Californian Bearing Ratio CBR and the unsoaked Californian Bearing Ratio increase with increasing of crushed basanite. Finally the minimum value of UCS obtained from the mixture materials is 1.67 MPa. Therefore, this physical treatment of fine lateritic soils, allows the increase of their bearing capacity. Starting from 30% of mixing, the bearing capacity values are desirable for sub-base material.

A method for the preparation of a compound adsorbent for Eucalyptus and CaCl2

In this study, composite adsorbent of Eucalyptus and CaCl2 has been prepared by carbonation method. The effects of the weight ratio, carbonation temperature and carbonation time were studied. The best conditions for composite adsorbent (Ca-AC) were obtained: the carbonation temperature was 650 °C; the weight ratio of CaCl2 to the eucalyptus sawdust was 2:1; the carbonation time was 80 min. the iodine adsorption value was 529 mg·g−1; the methylene blue adsorption value was 98.52 mg·g−1; After carbonation, the activated carbon surface is smooth, no sediment, and filled with different size and shape of pore structure, the size and quantity are increased. The feasibility and characteristics of the preparation of Eucalyptus and CaCl 2 composite adsorbents by carbonization were verified by experiments.

Production of Activated Carbon from Cow Manure for Wastewater Treatment

This study presents the chemical compositional analysis of cow manure in terms of holocellulose (35.97%), lignin (19.02%), and ash (17.47%). Activated carbons (of specific surface area 114 to 893 m2/g, iodine value 219 to 718 mg/g, methylene blue adsorption value 40.5 to 501 mg/g, and ash 16.17% to 22.3%) were prepared from cow manure by using various activator compounds such as potassium carbonate. The results showed that the activation effect of potassium carbonate and zinc chloride was better under the given conditions. The main ash found in the activated carbons was silica, which was reduced to about 3% by washing with sodium hydroxide solution. The prepared activated carbons were used to treat the wastewater from the cow farm and for the pollutant removal that effectively met the discharge standard requirements. These results indicated that the production of activated carbons from cow manure is a promising method for the cleaner production in intensive dairy farms.

Photocatalytic degradation of methylene blue by nanostructured Fe/FeS powder under visible light

The photocatalytic performance of mechano-thermally synthesized Fe/FeS nanostructures formed from micron-sized starting materials was compared with that of a thermally synthesized nanostructure with nano-sized precursors in this paper. The properties of as-synthesized materials were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), diffuse reflectance spectroscopy (DRS), and ultraviolet-visible (UV-Vis) spectroscopy. The effects of irradiation time, methylene blue (MB) concentration, catalyst dosage, and pH value upon the degradation of MB were studied. Magnetic properties of the samples showed that both as-synthesized Fe/FeS photocatalysts are magnetically recoverable, eliminating the need for conventional filtration steps. Degradation of 5 ppm of the MB solution by mechano-thermally synthesized Fe/FeS with a photocatalyst dosage of 1 kg/m3 at pH 11 can reach 96% after 12 ks irradiation under visible light. The photocatalytic efficiency is higher in alkaline solution. The kinetics of photocatalytic degradation in both samples is controlled by a first-order reaction. However, the rate-constant value in the thermally synthesized Fe/FeS photocatalyst sample is only 1.5 times greater than that of the mechano-thermally synthesized one.

Estimation of Soil‐Water Characteristic Curve for Cohesive Soils with Methylene Blue Value

This study described a new methylene blue test to measure the methylene blue value (MBV) for 15 cohesive soils and established the relationship between MBV and plasticity index (PI) and between MBV and percent passing No. 200 sieve (P200), respectively. Thereafter, the soil‐water characteristic curves (SWCCs) for 15 cohesive soils based on Fredlund and Xing’s model were generated by the pressure plate test. Then, regression equations for determining the four fitting parameters in a previously developed SWCC equation by using the measured MBV were utilized to generate the SWCC for the cohesive soils. At the same time, the slope parameter, bf, in the SWCC equations was found to be associated with the moisture susceptibility of cohesive soils. A higher bf value indicates that the material is more moisture susceptible. In addition, a lower MBV/PI/P200 shows a lower suction at the same degree of saturation; on the other hand, a higher MBV/PI/P200 presents a higher suction. Therefore, the moisture‐holding capacity of cohesive soils increases with increasing MBV, PI, and P200. Finally, the proposed estimation method was validated by a comparison between the four determined fitting parameters from MBV and the pressure plate test.

Fabricated CeO2 nanopowders as a novel sensing platform for advanced forensic, electrochemical and photocatalytic applications

In Forensic investigation, identification of various types of ridge details are essential in order to fix the criminals associated in various crimes. Even though several methods and labeling agents are available to visualize latent finger prints (LFPs) there is still simple, accurate, cost-effective, and non-destructive tool is required. In the present work, CeO2 nanopowders (NPs) are prepared via simple solution combustion route using Tamarindus indica fruit extract as a fuel. The optimized NPs are utilized for visualization of LFPs on various surfaces by powder dusting method. Results revealed that visualized LFPs exhibit Level 3 features such as pores and ridge contours under normal light with high sensitivity and without background hindrance. The photometric characteristics of the prepared samples exhibit blue color emission and highly useful in warm light emitting diodes. The photocatalytic studies were carried out with different Methylene blue (MB) dye concentration and pH values. The obtained results reveal that the CeO2 NPs exhibits an excellent catalytic properties which can act as a good catalytic reagent. The findings demonstrate that the prepared NPs are quite useful as a labeling agent for visualization of LFPs, efficient catalysts for dye degradation as well as solid-state lighting applications.

Influence of chemical-mineralogical properties of limestone on the shrinkage behaviour of cement paste and concrete made of limestone-rich cements

Shrinkage in concrete structures may lead to cracks which reduce the durability of concrete against aggressive mediums. In prestressed concrete elements shrinkage results in a significant loss of prestressing forces. Limestone-rich cements with limestone contents beyond the values of DIN EN 197-1 were developed in order to reduce the environmental impact of concrete. In this paper, the results of studies on the shrinkage behaviour of cement paste and concrete made of limestone-rich cements up to 70wt.-% are presented. Results indicated that shrinkage of cement paste and concrete with high limestone contents is strongly dependent on the amount and the chemical-mineralogical properties of limestone. In this context, methylene blue value (MB-value) and alkali oxide content of limestone were identified as the key parameters controlling the drying shrinkage of cement pastes. Depending on the type of limestone, concrete samples made of limestone-rich cements had either higher or lower drying shrinkage than reference samples made of CEM I 52.5 R with the same w/c-ratio. However, lower drying shrinkage deformation was observed in comparison to the reference concrete made of CEM I with a comparable compressive strength. Furthermore, it was ascertained that the contribution of the autogenous shrinkage and carbonation shrinkage to the total shrinkage deformation is almost negligible for cement paste and concrete made of limestone-rich cements.

Characterization and prediction of permanent deformation properties of unbound granular materials for Pavement ME Design

The objective of this study is to characterize and predict the permanent deformation properties of unbound granular materials (UGMs) for Pavement ME Design. First, laboratory repeated load triaxial (RLT) tests are conducted on the UGMs from 11 quarries in Texas to measure the permanent strain curves. The shakedown theory is applied to evaluate the permanent deformation behavior of the selected UGMs. It is found that using Werkmeister’s criteria to define the shakedown range boundaries is not suitable for the selected UGMs. Under this circumstance, new criteria are proposed to redefine the shakedown range boundaries for the flexible base materials in Texas. The new criteria are consistent with the current Texas flexible base specification in terms of aggregate classification. Second, the mechanistic-empirical design guide (MEPDG) model is used to determine the permanent deformation properties of the selected UGMs on the basis of the measured permanent strain curves. The determined permanent deformation properties are assigned as target values for the development of permanent deformation prediction models. Third, a series of performance-related base course properties are used to comprehensively characterize the UGMs, which include the dry density, moisture content, aggregate gradation, morphological properties, percent fines content, and methylene blue value. These performance-related base course properties are assigned as the inputs of the permanent deformation prediction models. Fourth, a multiple regression analysis is conducted to develop the prediction models for permanent deformation properties using these performance-related properties. The developed models are capable of accurately predicting the permanent deformation properties of UGMs. Compared to other prediction models (e.g., simple indicators-based models and Pavement ME Design models), the developed models have the highest prediction accuracy. It is also found that the Pavement ME model-predicted permanent strains are much lower than those measured from the RLT tests. This demonstrates that the current Pavement ME Design software substantially underestimates the rutting that occurs in base course. Finally, the developed prediction models are validated by comparing the predicted and measured permanent strains of other four base materials. The obtained R-squared value of 0.81 indicates that the developed models have a desirable accuracy in the prediction of permanent deformation properties of UGMs.

Study of the combination of sulfuric acid treatment and thermal regeneration of spent powdered activated carbons from decolourization process in glucosamine production

In this study, the combination of sulfuric acid treatment and thermal regeneration of spent powdered activated carbon (SPAC) saturated with color impurities and pigments was analyzed. The purposes of this work was to investigate effect of regeneration temperature on spent powdered activated carbons pretreated by H2SO4 solution (SPAC-H2SO4), and characterize porosity structure and property of regenerated samples by TG, BET, and FTIR methods in order to infer regeneration mechanism. The results showed that sintering rate of SPAC-H2SO4 was higher than that of SPAC at any temperature, indicating that H2SO4 pretreatment made SPAC more conducive to pyrolysis. Regeneration temperature had a noticeable effect on the regenerated yield. The optimal regeneration effect was obtained at 600°C for SPAC-H2SO4. The iodine value, MB value, and SBET of SPAC-H2SO4-600 were 1294.69mg/g, 13.97mL/0.1g, and 1839.09m2/g, respectively, which accounted for 99%, 93%, and 87% of fresh PAC, respectively. The adsorption rate of SPAC-H2SO4-600 and virgin PAC for methylene blue (MB) solution both followed well pseudo-second-order kinetics. These results indicated that combination of sulfuric acid treatment and thermal regeneration was a promising method for SPAC regeneration.

Hazard susceptibility related to clay shrinkage–swelling phenomena in north-eastern Tunisia (Grombalia area)

The investigation of the shrinkage–swelling phenomena in argillaceous formations of the Grombalia area (north-eastern Tunisia) has allowed the identification of three classes of clays. The first class contains three argillaceous formations and has a low susceptibility towards shrinkage–swelling phenomena. The second class, represented by four argillaceous formations, has an average susceptibility. The third class, comprises four argillaceous formations that have a high susceptibility. Therefore, in the study region, the hazard susceptibility towards the constructions can be significant for certain zones, because of the extension of constructions which is the result of the development of demography and industry in the recent years. Three indices have been determined to obtain these classes: the lithology indices, the mineral composition indices and the geotechnical indices. A description of the lithology of geological formations and X-ray diffraction results from analysis on bulk samples allow recognising the amount of clays in each formation. However, argillaceous formations composed essentially by clays does not mean that it has a high susceptibility towards shrinkage–swelling phenomena. To improve interpretation, XRD results reveal the volume proportion of minerals that exists in each argillaceous formation. Indeed, formations having high susceptibility towards shrinkage–swelling phenomena show a high volume of smectites and/or interstratified. The additional data provided from geotechnical study on argillaceous formations have allowed an inference about the degree of the shrinkage–swelling susceptibility for all the argillaceous formations in the Grombalia area. In fact, geotechnical results have allowed determining the plasticity index value, the methylene blue value and the linear shrinkage value. Determining the degree of the shrinkage–swelling susceptibility must be inferred from the three indices (lithology, mineralogy and geotechnical), because applying only the results of one feature can lead to a false decision.

Ultrasonic treatment of wastewater contaminated with various dyes using tin oxide hydroxide nanoparticles loaded on activated carbon: Synthesis, performance, mechanism and statistical optimization

Present research describe applicability of tin oxide hydroxide nanoparticles loaded on activated carbon (Sn6O4 (OH)4‐NPs‐AC) which recognized via by Field emission scanning electron microscopy (FE‐SEM) and X‐ray diffraction (XRD) for the rapid simultaneous removal of Methyl orange (MB) and methylene blue (MB) in mixture in the presence of ultrasonic wave. The central composite design (CCD) pattern as branch of response surface methodology (RSM) give useful information about influence of five most important operating variables is separate and combination nature namely pH (4.0–8.0), initial MO (8–24 mg L−1) and MB concentration (4–12 mg l−1), sonication time (2–6 min) and adsorbent mass (0.01–0.03 g) on the ultrasound under study dyes assisted adsorption. After surveying the experiment data and finding regression analysis correspond to experimental data, mathematical model and equation was constructed and derived which applied for optimizing ultrasound assisted adsorption and revel serious dependency of response to variables like adsorbent mass and sonication time s. F values of 114.5 and 165.5, coefficient of determination (R2) of 0.9978 and 0.9985, adjusted‐R2 of 0.9891 and 0.9925, adequate precision (AP) of 39.11 and 40.23, coefficient of variation (CV) of 0.653 and 1.988% for MB and MO respectively, implied the satisfactory adjustment of the quadratic model. Based on CCD, the optimum conditions was set as pH of 6.0; 0.02 g adsorbent; 20 and 12 mg l−1 of MO and MB concentration and 2 min sonication time. The predicted removal of MO and MB in binary system were 98.19 and 98.02% which was good agreement with their experimental R% MO and MB value of 98.00% for both at optimum condition. The equilibrium data has good agreement with Langmuir with maximum monolayer adsorption capacity of 30.90 and 25.70 mg g−1 for MO and MB respectively. Investigation of time dependency of adsorption data revel more applicability pseudo‐second order in cooperation with intraparticle diffusion description of the mechanism and adsorption rate.

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.

Effect of biopolishing on structural degradation and physical properties of cellulose

Cellulase treatment on cotton fabric is ecofriendly way of biopolishing. In the present work, biopolishing of cotton fabric using free and immobilized cellulase under various treatment conditions have been carried out using Box-Behnken design and the physical properties like pilling grade, abrasion resistance and flexural rigidity were analyzed. The degradation of cotton fabric minimized and similar results were obtained for pilling and abrasion resistance of free and immobilized cellulase treatment. Higher flexural rigidity is the result of immobilized cellulase treated fabric when compared with the free cellulase. The degradation of amorphous region improves the crystallinity index of the treated samples. This shows that the amorphous region were more prone to enzymatic attack than the crystalline regions. The enzymatic treatment increase the accessible surface area of cotton fibre and it can be measured by Methylene blue absorption value. Methylene blue absorption of the fabric was more for free cellulase than the immobilized cellulase treated fabric. The change in hydrogen bond by the treatment was measured and analyzed by the Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR).

Co-production of Biochar, Bio-oil, and Syngas from Tamarix chinensis Biomass under Three Different Pyrolysis Temperatures

Pyrolysis of Tamarix chinensis feedstock was performed at 300, 500, and 700 °C to investigate the characteristics of biochar, bio-oil, and syngas. Biochar yield decreased and syngas yield increased as the pyrolysis temperature increased. The biochar was characterized for elemental composition, surface, and adsorption properties. Values of pH, electrical conductivity (EC), ash, C, K, Na, and basic functional group contents all increased as the pyrolysis temperature increased, whereas P, Ca, Mg, and acidic functional groups decreased. The methylene blue adsorption capacity values were 1.78, 2.08, and 1.96 (mg g-1) and iodine 256.48, 255.51 and 76.42 (mg g-1) for the biochars produced at 300, 500, and 700 °C, respectively. The C and H contents in bio-oil ranged from 66 to 62% and 8 to 7%, while O changed from 25 to 29% when temperature was increased from 300 to 700 °C. The concentration of hydrocarbon gases, such as ethane, ethylene, propane, and acetylene, increased as the pyrolysis temperature increased. The sum of CO and CO2 occupied great percentage of the total gas, while the H2 concentration increased markedly to a maximum of 16% at 500 °C. Thus, T. chinensis is a potential feedstock for biochar and bioenergy production.

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.

Relationships between modified methylene blue value of microfines in manufactured sand and concrete properties

To better understand and assess the effect of microfines on concrete properties, the synergetic effect of methylene blue value and content of microfines on properties of low and high strength concrete was studied and then the relationships between the index of modified methylene blue value (MMBV) and concrete properties were investigated. The results show that relationships between MMBV and fresh and hardened properties of concrete can be fully established, and the correlation between MMBV and C60 concrete property is higher than the correlation between MMBV and C30 concrete. With the increase of MMBV, concrete workability and frost resistance decrease while drying shrinkage decreases; however, compressive strength and chloride-ion penetration resistance of C30 concrete have not been negatively affected whereas those of C60 concrete are significantly deteriorated when MMBV exceeds 100. To make use of microfines without remarkably damaging concrete quality, it is suggested that MMBV of microfines in MS used in C30 and C60 concrete be no more than 100.