Methylene Blue Value Research Articles

Biochar from oil cakes: an efficient and economical adsorbent for the removal of acid dyes from wool dye house effluent

In the reported study, biochars were prepared from almond, coconut, and mustard oil cakes by chemical activation with phosphoric acid followed by low-temperature pyrolysis. The ball milling technique was employed to reduce the particle size of the biochars below 300 nm. The synthesized biochars were characterized by various analytical techniques like Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, X-ray diffraction spectroscopy, BET surface analysis, porosity measurement, methylene blue value and further employed for the removal of color from the acid dye effluent from the wool dyeing unit. The results showed that very small quantities (2.0 %) of biochars are sufficient to remove around 92% color from the dye effluent. The adsorption properties of the synthesized biochars were found to be greatly depending on the type of oil cake used. Among the three selected oil cakes, viz. mustard, coconut, and almond, the later was found to be performed well in terms of color removal. The batch adsorption and kinetic studies indicate the second order pathway of color removal for the synthesized biochars.

Analysis of the physical, hydraulic, and mechanical properties of sugar bagasse ash-clay geomaterial

Sugar cane bagasse ash (SA) is the result of the incineration of residues in the production of sugar which has as its final disposal the sanitary landfills generating environmental impacts. The practice of the circular economy for using SA ash as a stabilizer of clay soils in highway bases and sub-bases requires the study of the potential of ash as an alternative cement. Soil stabilization is commonly done with the addition of cement or lime; however, the production of these materials releases CO2 into the atmosphere. This research estimates the potential use of SA ash as a cementing agent considering the physical, hydraulic, and mechanical properties of clay soil mixed with percentages of 6, 8, and 10% of Uncalcined Sugarcane Bagasse Ash (USA) and Calcined Sugarcane Bagasse Ash (CSA). X-ray fluorescence spectrometry (FRX), methylene blue value test, specific gravity, dry unit weight, granulometric analysis, and Atterberg limits tests were carried out to evaluate the physical properties of the mixtures. One-dimensional consolidation tests, soil water characteristic curves (SWCC), standard Proctor compaction, unconfined compression, and direct shear were carried out to estimate the mechanical and hydraulic properties of the mixtures. An improvement in the physical, hydraulic, and mechanical properties was found with the addition of USA and CSA. Finally, based on the analysis of the physical, hydraulic, and mechanical properties of the Soil-USA and soil-CSA samples, it was determined that the best option as an alternative cementitious agent is found in the 8% Soil-CSA mixture due to the improvement in the plasticity index, gravity density, angle of friction, cohesion, and unconfined compressive in comparison with the other samples and the original soil. However, it is essential to mention that this cementitious addition can prejudice the hydraulic properties and consolidation process. It is vital to consider those parameters when realizing any geotechnical design with this mixture.

Characterization of the Activity, Mineralogy and Correlations between the Properties of Clayey Soils

The activity is related to the mineralogy and geological history of clays. Soils with the same value of the liquidity limit or plasticity index can have very different characteristics depending on the amount and type of clay minerals. The methylene blue value characterizes the activity of the clays and reflects the surface activity. Ten inactive soils contain minerals (kaolinite, illite), these soils absorb little water. Two swelling soils have normal activity and are composed of minerals (kaolinite, illite, Montmorillonite). The relationships between clayey soils properties, their activities and between the activity and the liquidity limit are defined. The correlations obtained are linear fit and exponential and sigmoidal fits. The correlations obtained with a coefficient of determination of R2 (0.859 - 0.999) can be used to characterize and predict certain parameters of fine-grained soils as a function of clay content.

High Surface Area Nanoporous Activated Carbons Materials from Areca catechu Nut with Excellent Iodine and Methylene Blue Adsorption

Nanoporous carbon materials from biomass exhibit a high surface area due to well-defined pore structures. Therefore, they have been extensively used in separation and purification technologies as efficient adsorbents. Here, we report the iodine and methylene blue adsorption properties of the hierarchically porous carbon materials prepared from Areca catechu nut. The preparation method involves the phosphoric acid (H3PO4) activation of the Areca catechu nut powder. The effects of carbonization conditions (mixing ratio with H3PO4, carbonization time, and carbonization temperature) on the textural properties and surface functional groups were studied. The optimum textural properties were obtained at a mixing ratio of 1:1, carbonized for 3 h at 400 °C, and the sample achieved a high specific surface area of 2132.1 m2 g−1 and a large pore volume of 3.426 cm3 g−1, respectively. The prepared materials have amorphous carbon structures and contain oxygenated surface functional groups. Due to the well-defined micro-and mesopore structures with the high surface area and large pore volume, the optimal sample showed excellent iodine and methylene blue adsorption. The iodine number and methylene blue values were ca. 888 mg g−1 and 369 mg g−1, respectively. The batch adsorption studies of methylene dye were affected by pH, adsorbent dose, contact time, and initial concentration. The optimum parameters for the methylene blue adsorption were in alkaline pH, adsorbent dose of 2.8 g L−1, and contact time of 180 min. Equilibrium data could be best represented by the Langmuir isotherm model with a monolayer adsorption capacity of 333.3 mg g−1. Thus, our results demonstrate that the Areca catechu nut has considerable potential as the novel precursor material for the scalable production of high surface area hierarchically porous carbon materials that are essential in removing organic dyes from water.

Pyrolysis of pellets prepared from pure and blended biomass feedstocks: Characterization and analysis of pellets quality

Recently, pyrolysis integrated with pelletization has received great attention. In the current study, various physical, mechanical, chemical and thermal characteristics of furfural residue pellets (FRPs), sewage sludge pellets (SSPs), furfural residue-sewage sludge pellets (FRSSPs) were studied at different pyrolysis temperature (200–850 °C) and residence time (15–45 min). The mass and energy yields of pellets dropped drastically with increasing pyrolysis temperature. Higher heating values (HHV) of pyrolysed furfural residue pellets (PYFRPs) and furfural residue-sewage sludge pellets (PYFRSSPs) increased from 22.22 to 26.76 MJ/kg, and 20.59–23.72 MJ/kg, respectively with increasing temperature from 200 to 850 °C. However, the HHV of pyrolysed sewage sludge pellets (PYSSPs) decreased with increasing temperature. The lowest pellet density and strength were found at 850 °C and residence time of 45 min. The pellets remained dimensionally stable during the water immersion test and after a storage time of 2 weeks, the relaxed densities and strength remained unchanged. The volumetric energy density of PYFRPs (30.35 kJ/m3) was found to be higher than PYSSPs (8.92 kJ/m3) and PYFRSSPs (23.85 kJ/m3) at the same process conditions. Thermal treatment enhanced the hydrophobicity of pellets. The lowest moisture uptake of 1.14 wt%, 1.8 wt%, and 1.58 wt% for the corresponding PYFRPs, PYSSPs and PYFRSSPs were observed at pyrolysis temperature of 300 °C. The maximum methylene blue and iodine adsorption values (i.e. 96 and 244.8 mg/g), (191 and 314.7 mg/g) and (121.6 and 263 mg/g) for PYFRPs, PYSSPs and PYFRSSPs were found, respectively, at temperature of ≥ 450 °C. Pyrolysis at higher temperature significantly reduced the heavy metals in PYFRSSPs and PYSSPs.

Effect of Manufactured Sand with Different Quality on Chloride Penetration Resistance of High-Strength Recycled Concrete.

High–strength manufactured sand recycled aggregate concrete (MSRAC) prepared with manufactured sand (MS) and recycled coarse aggregate (RCA) is an effective way to reduce the consumption of natural aggregate resources and environmental impact of concrete industry. In this study, high–, medium– and low–quality MS, which were commercial MS local to Changzhou and 100% by volume of recycled coarse aggregate, were used to prepare MSRAC. The quality of MS was determined based on stone powder content, methylene blue value (MBV), crushing value and soundness as quality characteristic parameters. The variation laws of compressive strength and chloride penetration resistance of high–strength MSRAC with different rates of replacement and different qualities of MS were explored. The results showed that for medium– and low–quality MS, the compressive strength of the MSRAC increased first and then decreased with increasing rate of replacement. Conversely, for high–quality MS, the compressive strength gradually increased with increasing rate of replacement. The chloride diffusion coefficient of MSRAC increased with decreasing MS quality and increasing rate of replacement. The chloride diffusion coefficient of MSRAC basically met the specifications for 50–year and 100–year design working life when the chloride environmental action was D and E. To prepare high–strength MSRAC, high–quality MS can 100% replace RS (river sand), while rates of replacement of 50–75% for medium–quality MS or 25–50% for low–quality MS are proposed. Scanning Electron Microscope (SEM) images indicated that an appropriate amount of stone powder is able to improve the compressive strength of RAC, but excessive stone powder content and MBV are unfavorable to the compressive strength and chloride penetration resistance of RAC.

Pyrolysis of furfural residue pellets: Physicochemical characteristics of pyrolytic pellets and pyrolysis kinetics

Biomass pelletization technology has recently gained significant interest, where pyrolyzed pellets have a very wide range of applications (e.g., as pellet fuels and adsorbents). In this study, furfural residue pellets (FRPs) were pyrolyzed at temperatures of 200–850 °C in a tube furnace. The physical and chemical properties of the pyrolyzed FRPs (PFRPs) obtained at various temperatures were compared, and the kinetic parameters of the pyrolysis process were calculated using the distributed activation energy model (DAEM). The PFRPs prepared at 450, 650, and 850 °C had higher volumetric energy densities than coal, whereas other properties (e.g., H/C and O/C ratios) were found to be similar to those of coal. The maximum iodine adsorption value (i.e. 317.8 mg/g) and methylene blue adsorption value (i.e. 96.4 mg/g) were achieved by pyrolysis at 650 °C and 450 °C, respectively, indicating that pyrolysis promoted the formation of micropore structures at 650 °C. Two-dimensional correlation spectroscopy (2D-COS) was employed to explore the temperature-sensitivity of the surface functional groups of the PFRPs. Based on comparison of the volumetric energy density, hydrophobicity, particle density, and strength, the PFRPs prepared at 250–300 °C afforded the best overall performance, where the sample prepared at 300 °C exhibited the maximum hydrophobicity.

Petroleum oil and products recovery from oily sludge: Characterization and analysis of pyrolysis products

Oily sludge (OS) has attracted special interest because of its hazardous nature and high potential as an energy resource. This study investigated the oil recovery from OS by thermal cracking and catalytic pyrolysis. The oil yield increased when the temperature exceeded 450 °C and reached a maximum (76.84 wt%) at 750 °C. Catalysts significantly improved the quality of oil produced during catalytic pyrolysis. Aromatic hydrocarbons were dominant (10.01–52.69%) in pyrolysis oil (PO) from OS catalytic pyrolysis, and the catalysts significantly reduced the presence of oxygen heterocycles. In addition, KOH and CaO reduced the ID (D-band peak intensity)/IG (G-band peak intensity) of OS char (OC) and increased the degree of graphitization. Owing to its higher iodine adsorption value and methylene blue (MB) adsorption value, OC exhibits potential as an adsorbent. The environmental assessment and potential applications of OC, along with possible reaction mechanisms and kinetic characteristics, are also discussed.

Adsorption Analysis by Activated Carbon Derived from Nut Shells

Walnut, pistachio and chestnut shells are wonderful precursors for activated carbon. Due to the country’s tremendous output and consumption of the nuts, a huge amount of nut shells are produced in China every year. In this study, activation temperature, activation time, impregnation ratio and zinc chloride activator concentration for high quality activated carbon formation are investigated experimentally by the methylene blue adsorption method. Copper ion adsorption is also analyzed. Chestnut shell is the most suitable material for activated carbon preparation. With 357mg/g methylene blue adsorption value, that is 2.6 times as the China’s national standard. All three types activated carbon show the highest copper ion adsorption when the concentration of copper sulfate is 50ppm, and the maximum adsorption capacity is 1.06mg/g.

Clayey soils from Boulgou (North Cameroon): geotechnical, mineralogical, chemical characteristics and properties of their fired products

In this study, clayey soils are characterized as backfill and potential fusible raw materials for engineering. Geotechnical tests (particle size distribution, Atterberg limits, densities) and chemico-mineralogical analyses (X-ray fluorescence, X-ray diffraction and Fourier transform infrared) were carried out on samples collected from field in the locality of Boulgou (North Cameroon) followed by the determination of mechanical properties of fired bricks (850–1200 °C). The excavations carried out have revealed a thick layer of clayey soils (~ 2 to 2.5 m) over a sandy layer. This clay formation presents some stratifications with limited influence variation in terms of mineralogy. Mean grain size distribution is dominated by sand (62–80%), clay (12–25%) and silt (6–9%). It corresponds to silty–clayey soils regarding their methylene blue values (3.3–5.6), with low plastic (13–22%) to high plastic (33%) characteristics. They are classified by USCS as clayey sand/silty clay, while one sample is a poorly graded sand (SP). Clay minerals observed are kaolinite (6–12%), montmorillonite (2–6%) and illite (8–10%). Those parameters associated with their fine nature and high compressibility make them suitable engineering applications for backfill material and barriers. From chemical analyses, relatively high contents in alkali and alkaline earth elements (~ 4 to 6%) to be used as potential fusible raw materials for fired bricks or gres ceramics were revealed. Bricks characteristics are varied: linear shrinkage (0.3 to 9%), bulk density (1.8 to 2.3 g/cm3), water absorption (19.7 to 1.3%) and flexural strength (0.3 to 17.4 MPa). Overall, the requirement for fired brick (< 20%) is met up by the water absorption values. As from 1050 °C, these soils are made suitable for brick-making with good characteristics (metallic sound, good cohesion and flexural strength).

The influence of ophiolitic crushed fine aggregate properties on the performance of cement mortars

Aggregates constitute the largest proportion of the raw materials used for the production of mortars. Therefore, their quality significantly influences the in-use performance of the aforementioned composite building materials. This paper investigates the influence of ophiolitic crushed fine aggregate, quarried in Cyprus, on the performance of cement mortars. The experimental results vividly show that the mineralogical composition and physicomechanical properties of the fine aggregate materials under study highly affect the properties of the hardened cement mortars. More specifically, cement mortars prepared with “poor quality” aggregates, exhibiting high methylene blue and Micro-Deval loss values, showed inferior physicomechanical properties, compared to composites prepared with “better quality” aggregates. Sound correlations were also found between the mineralogy of aggregates and the physicomechanical properties of the hardened composites. This suggests that the combination of standardized aggregate characterization tests and mineralogical analyses may prove useful in assessing the quality of aggregates, prior to their use in mortar production.

Study on How to Determine the Methylene Blue (MB) Value of Machine-made Sand and Its Effects on Admixture Dosage and Compressive Strength of Concrete

Machine-made sand is a raw material commonly used in concrete production, and its quality has a very obvious effect on the performance of concrete. This paper conducted an experiment to determine the methylene blue (MB) value of machine-made sand, explored the effects of the value changes on the admixture dosage and compressive strength of concrete, and analyzed the mineral components of machine-made sand. The research results show that the mud dosage in machine-made green sand is relatively higher, and the admixture dosage increases along with the increasing of the MB value. The mixing of different types of machine-made sand has a certain effect on the compressive strength, which reaches the peak at a certain ratio.

Preparation of Flax Residue Activated Carbon by KOH Method and Its Electrode Performance

In this study, activated carbon was prepared by the potassium hydroxide activation method with flax residues as raw materials. High-quality activated carbon was prepared by single factor and orthogonal experiments. Iodine adsorption and methylene blue adsorption were used as performance indicators. As prepared activated carbon was characterized by XRD, XPS and SEM. The results showed that the optimized electrode material was prepared under an impregnation ratio of 1:2, activation temperature of 800°C and activation time of 100 min. The yield of activated carbon was 49.48%, the iodine value was 1667.13 mg/g and the methylene blue value was 429 mg/g. The specific surface area measured by the automatic porosity analyzer is 1221 m2/g, and the mass-specific capacitance is 215.7 F/g under current density of 0.1 A/g.

Affordable Water Filtration Technology for Disinfection By-Product Control for Small Rural Communities by Using Carbon Extracted from Local Fly Ash

The fly ash generated from local pulp and paper industries was transformed into activated carbon (AC) through physical activation process in a high temperature tube furnace in this study. Effects of two factors including activation temperature and activation time were investigated. Iodine number (IN), methylene blue value (MBV), and surface microstructure were all analyzed to assess the adsorption capacity of different carbon samples. The surface area of the carbon sample increased significantly from 486.44 m2/g to 847.26 m2/g before and after activation. The jar tests revealed that the use of 0.5 g (AC)/L (water) has the highest adsorption effectiveness. Meanwhile, the column filtration experiment indicated more than 60% of the organic matter can be removed by the carbon barrier within 2 hours filtration. The follow-up chlorination experiment illustrated that the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) could be considerably prevented after filtration. Above all, the cost-effective carbon filtration technology developed in this study can potentially be applied as a pre-treatment technology for intake source waters for local communities.

Effect of pretreatment conditions on the chemical–structural characteristics of coconut and palm kernel shell: A potentially valuable precursor for eco-efficient activated carbon production

Non-renewable nature of commercial coal-based activated carbon has pushed researchers to look for sustainable alternatives which are inexpensive and abundantly available such as palm kernel shell (PKS) and coconut shell (CS). In this study, preparation of the lignocellulosic biomass using acid (H 3 PO 4 ), alkali (NaOH) and water pretreatment have been investigated. Pretreatment temperature and time were determined as the significant factors on the chemical–structural characteristics of CS and PKS. In addition, BET, SEM, FTIR, TGA were used to elucidate the development of PKS and CS and its capacity towards the adsorption of methylene blue and iodine. By varying the pretreatment conditions and process, it offers the possibility of modifying and controlling the porous texture of the biomass to prepare it as potential precursor for further physical thermal process during activated carbon production. The pretreated biomass results showed that the adsorption of methylene blue (14.35–16.92​ mg/g) and iodine value (20.14–23.86 mg/g) were significantly higher than non-treated biomass (methylene blue adsorption: 1.71–1.79 mg/g, iodine adsorption: 0.77–1.28 mg/g). Moreover, the results also revealed that pretreatment temperature and time have significantly affected the adsorbent properties of biomass. The pretreatment of biomass with H 3 PO 4 created a better development of porous structure. The highest surface area for CS (89.09 m 2 /g) and PKS (70.01 m 2 /g) were attained by using H 3 PO 4 at 80 °C for 2 h. The impregnation pretreatment simultaneously unclog existing pores from ash minerals while create new cracks and pores. • Impregnation-pretreated lignocellulosic biomass as potential precursors for activated carbon. • Chemical-structural characteristics of the pretreated coconut and palm kernel shell were analysed. • H 3 PO 4 pretreated biomass has better characteristics to be further process into activated carbon. • Among pretreatments, NaOH causes the highest severity on biomass with large pores. • Impregnation pretreatments unclog existing pores from minerals and create new cracks and pores.

Preparation and characterization of bio-based activated carbon from fish scales

The object of this study was to prepare activated carbons containing nitrogenous functional groups by a chemical method from nitrogen-containing raw materials. Fish (Ctenopharyngodon idellus) scales were impregnated with phosphoric acid (H3PO4) and activated at varied temperatures. The adsorption ability, structural characteristics, surface chemistry, and morphology of the activated carbons were characterized by methylene blue and iodine values, nitrogen adsorption, the Boehm method, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The total alkaline groups content of the activated carbon produced from fish scales was 0.4330 mmol/g, the total acidic groups was 1.68 mmol/g, the Brunauer–Emmett–Teller (BET) surface area was 501 cm2/g, and the total pore volume was 0.284 cm3/g. The average pore diameter was 1.94 nm under an activation temperature of 550 °C, an activation time of 1 h, and an impregnation ratio of 2. As a result of this study, nitrogenous functional groups that contained acid-base amphoteric adsorbent were produced.

Sorption of Methylene Blue for Studying the Specific Surface Properties of Biomass Carbohydrates

The surface area is an important parameter in setting any biorefining technology. The aim of this study was to investigate the applicability of sorption of methylene blue to characterize the surface of the main biomass carbohydrates: α-cellulose, sigmacell cellulose, natural gum, β-glucan, and starch. The morphology of particles of the model objects was studied by scanning electron microscopy. Nitrogen adsorption isotherms demonstrate that the selected carbohydrates are macroporous adsorbents. The monolayer capacities, the energy constants of the Brunauer–Emmett–Teller (BET) equation, and specific surface areas were calculated using the BET theory, the comparative method proposed by Gregg and Sing, and the Harkins–Jura method. The method of methylene blue sorption onto biomass carbohydrates was adapted and mastered. It was demonstrated that sorption of methylene blue proceeds successfully in ethanol, thus facilitating surface characterization for carbohydrates that are either soluble in water or regain water. It was found that the methylene blue sorption values correlate with specific surface area determined by nitrogen adsorption/desorption and calculated from the granulometric data. As a result of electrostatic attraction, the presence of ion-exchanged groups on the analyte surface has a stronger effect on binding of methylene blue than the surface area does. Sorption of methylene blue can be used in addition to gas adsorption/desorption to assess the accessibility of carbohydrate surface for binding large molecules.

Methylene blue inhibits replication of SARS-CoV-2 in vitro

In December 2019, a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing coronavirus diseases 2019 (COVID-19) emerged in Wuhan, China. Currently there is no antiviral treatment recommended against SARS-CoV-2. Identifying effective antiviral drugs is urgently required. Methylene blue has already demonstrated in vitro antiviral activity in photodynamic therapy as well as antibacterial, antifungal and antiparasitic activities in non-photodynamic assays. In this study. non-photoactivated methylene blue showed in vitro activity at very low micromolar range with an EC50 (median effective concentration) of 0.30 ± 0.03 μM and an EC90 (90% effective concentration) of 0.75 ± 0.21 μM at a multiplicity of infection (MOI) of 0.25 against SARS-CoV-2 (strain IHUMI-3). The EC50 and EC90 values for methylene blue are lower than those obtained for hydroxychloroquine (1.5 μM and 3.0 μM) and azithromycin (20.1 μM and 41.9 μM). The ratios Cmax/EC50 and Cmax/EC90 in blood for methylene blue were estimated at 10.1 and 4.0, respectively, following oral administration and 33.3 and 13.3 following intravenous administration. Methylene blue EC50 and EC90 values are consistent with concentrations observed in human blood. We propose that methylene blue is a promising drug for treatment of COVID-19. In vivo evaluation in animal experimental models is now required to confirm its antiviral effects on SARS-CoV-2. The potential interest of methylene blue to treat COVID-19 needs to be confirmed by prospective comparative clinical studies.

Pyrolysis of furfural residue in a bubbling fluidized bed reactor: Biochar characterization and analysis

The pyrolysis characteristic of furfural residue (FR) was investigated in a fluidized bed reactor. The yield of biochar (BC) decreased whereas non-condensable gas yield increased with increasing temperature from 450 °C to 850 °C. The minimum BC yield (41.67 wt%) was found with addition of kaolin at 650 °C, while the maximum non-condensable gas yield (48.00 wt%) was obtained at 850 °C without additives. Furthermore, the maximum condensate yield (20.63 wt%) was observed at 650 °C with Ca-bentonite addition. Both Ca-bentonite and kaolin decreased the BC yield, while CaO promoted the BC yield. The contents of carbon, nitrogen and sulfur in BC were enriched at different temperatures. Ca-bentonite, kaolin and CaO resulted in more amount of protrusions on the BC surface and improved BC pore structures. Iodine and methylene blue adsorption values of BC were higher than that of FR and the maximum iodine adsorption value (279.6 mg/g) was obtained at 650 °C without additives. CaO remarkably increased methylene blue adsorption value, reaching the maximum value of 168.7 mg/g at 450 °C. A possible formation pathway of BC during FR pyrolysis was also proposed.

Preparation of cellulose/diatomite composite material and its adsorption characteristics and kinetics

The optimal preparation conditions for cellulose/diatomite composite adsorbents (CDAs) were determined to be a diatomite concentration of 40 wt%, a holding temperature of 700 °C, and a holding time of 30 min. Meanwhile, the yield of CDAs was 70.6%, and the methylene blue (MB) adsorption value was 191.8 mg/g. The specific surface area, total pore volume, and average pore size of the CDAs were 489 m2/g, 0.372 cm3/g, and 3.04 nm, respectively. It was inferred that the diatomite was cross-linked with the cellulose carbon to form some micropores. Greater MB initial concentrations and pH values improved the adsorption on the CDAs. The MB adsorption behavior of the CDAs was described very well by the pseudo-second-order model. The isotherm models showed relatively high adsorption of MB.