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

Abstract

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.

Physico-chemical, mineralogical, and technological characterization of stabilized clay bricks for restoration of Kasbah Ait Benhadou- Ouarzazate (south-east of Morocco)

“…This value is close to those determined for soils of similar composition, which can vary from 11.3 to 27.8 m 2 /g [34]. In general, the methylene blue method widely used by researchers when they do not have the possibility to use the BET, to have an approximate value of the SSA [35][36][37]. \The scanning electron microscope results of the studied debris confirm the dominance of the finest fraction (1 to 3 mm) and a rough texture.…”

Easy Preparation of Liposome@PDA Microspheres for Fast and Highly Efficient Removal of Methylene Blue from Water

“…The specific surface area of the Liposome@PDA microspheres was calculated with the following Equation [ 43 , 49 , 50 ]: where a is the area of a molecule of MB (1.3 * 10⁻ 1 ⁸ m 2 [ 51 , 52 ]). S MAX is the maximum level of adsorption, and N AV is the Avogadro’s number.…”

Alkalization of Kraft Pulps from Pine and Eucalyptus and Its Effect on Enzymatic Saccharification and Viscosity Control of Cellulose

“…Since cellulosic materials lose their inner porous structure when water is evaporated (hornification phenomenon) and conventional methods require sample drying [ 35 ], the SSA MB was estimated in pulp wet state. Additionally, the experiments were conducted at pH 5.5 to reduce the effect of chemical adsorption of MB on the fiber surface [ 32 ]. SSA MB results for eucalyptus samples ranged from 21 to 89 m 2 /g, while pine ranged from 5 to 20 m 2 /g, evidencing a meaningful difference on SSA MB values in both species.…”

“…The specific surface area (SSA), defined as the total surface area of a solid material per unit of mass, is an important feature for sorption processes. e.g., an increased substrate SSA improves cellulose adsorption and make enzymatic process more effective [ 31 , 32 ]. Assuming that MB forms a monolayer of adsorbed molecules on the surface of sorbent particles, the SSA can be calculated using Equation (2): where is the specific surface area (m 2 /g), is the maximum mass of adsorbed MB in the monolayer (g/g), is the surface area occupied by one MB molecule (m 2 /molecule) (typically assumed to be 130 Å 2 per molecule), is Avogrado’s number (6.02 × 10 23 molecule/mol) and is the MB molar mass (355.89 g/mol) [ 33 , 34 , 35 ].…”