Role of electro-surface and adsorption properties of coal and rocks in rebinder effect

To address the need to develop improved hybrid biopolymer composites, we report on the preparation of composites that contain chitosan and pectin biopolymers with tunable adsorption properties. Binary biopolymer composites were prepared at variable pectin–chitosan composition in a solvent directed synthesis, dimethyl sulfoxide (DMSO) versus water. The materials were characterized using complementary methods (infrared spectroscopy, thermal gravimetric analysis, pH at the point-of-zero charge, and dye-based adsorption isotherms). Pectin and chitosan composites prepared in DMSO yielded a covalent biopolymer framework (CBF), whereas a polyelectrolyte complex (PEC) was formed in water. The materials characterization provided support that cross-linking occurs between amine groups of chitosan and the –COOH groups of pectin. CBF-based composites had a greater uptake of methylene blue (MB) dye over the PEC-based composites. Composites prepared in DMSO were inferred to have secondary adsorption sites for enhanced MB uptake, as evidenced by a monolayer uptake capacity that exceeded the pectin–chitosan PECs by 1.5-fold. This work provides insight on the role of solvent-dependent cross-linking of pectin and chitosan biopolymers. Sonication-assisted reactions in DMSO favor CBFs, while cross-linking in water yields PECs. Herein, composites with tunable structures and variable physicochemical properties are demonstrated by their unique dye adsorption properties in aqueous media.

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Flax Biomass Conversion via Controlled Oxidation: Facile Tuning of Physicochemical Properties

Bioengineering ◽

10.3390/bioengineering7020038 ◽

2020 ◽

Vol 7 (2) ◽

pp. 38

Author(s):

Leila Dehabadi ◽

Abdalla H. Karoyo ◽

Majid Soleimani ◽

Wahab O. Alabi ◽

Carey J. Simonson ◽

...

Keyword(s):

Chemical Modification ◽

Pore Structure ◽

Surface Charge ◽

Chemical Treatment ◽

Textural Properties ◽

Adsorption Properties ◽

Biomass Composition ◽

Adsorption Sites ◽

Modified Forms

The role of chemical modification of pristine linen fiber (LF) on its physicochemical and adsorption properties is reported in this contribution. The surface and textural properties of the pristine LF and its peroxyacetic acid- (PAF) and chlorite-treated (CF) fiber forms were characterized by several complementary methods: spectroscopy (SEM, TEM, FT-IR, and XPS), thermal analysis (DSC and TGA), gas/water adsorption isotherms, and zeta potential (ξ). The results obtained reveal that the surface charge and textural properties (surface area and pore structure) of the LF material was modified upon chemical treatment, as indicated by changes in the biomass composition, morphology, ξ-values, and water/dye uptake properties of the fiber samples. Particularly, the pristine LF sample displays preferential removal efficiency (ER) of methylene blue (MB) dye with ER ~3-fold greater (ER~62%) as compared to the modified materials (CF or PAF; ER~21%), due to the role of surface charge of pectins and lignins present in pristine LF. At higher MB concentration, the relative ER values for LF (~19%) relative to CF or PAF (~16%) reveal the greater role of micropore adsorption sites due to the contributing effect of the textural porosity observed for the modified flax biomass at these conditions. Similar trends occur for the adsorption of water in the liquid vs. vapour phases. The chemical treatment of LF alters the polarity/charge of the surface functional groups, and pore structure properties of the chemically treated fibers, according to the variable hydration properties. The surface and textural properties of LF are altered upon chemical modification, according to the variable adsorption properties with liquid water (l) vs. water vapor (g) due to the role of surface- vs. pore-sites. This study contributes to an understanding of the structure-adsorption properties for pristine and oxidized flax fiber biomass. The chemical conversion of such biomass yields biomaterials with tunable surface and textural properties, as evidenced by the unique adsorption properties observed for pristine LF and its modified forms (CF and PAF). This study addresses knowledge gaps in the field by contributing insight on the relationship between structure and adsorption properties of such LF biomass in its pristine and chemically modified forms.

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Adsorption of nucleic acid bases on magnesium oxide (MgO)

International Journal of Astrobiology ◽

10.1017/s1473550412000444 ◽

2012 ◽

Vol 12 (1) ◽

pp. 78-86 ◽

Cited By ~ 19

Author(s):

Teresa Fornaro ◽

John Robert Brucato ◽

Sergio Branciamore ◽

Amaranta Pucci

Keyword(s):

Nucleic Acid ◽

Metal Oxides ◽

Magnesium Oxide ◽

Organic Molecules ◽

Adsorption Properties ◽

Equilibrium Adsorption ◽

Nucleic Acid Bases ◽

Adsorption Of Organic Molecules ◽

Emergence Of Life

AbstractThe adsorption of organic molecules on mineral matrices might have played a fundamental role in processes that led to the emergence of life. We investigated the adsorption properties of the nucleobases adenine, cytosine, uracil and hypoxanthine on magnesium oxide (MgO), determining the single solute batch equilibrium adsorption isotherms. Langmuir-type isotherms were fitted to data, assuming a rapid reversible equilibration of adsorption, demonstrated effectively through desorption experiments. The Langmuir equilibrium adsorption constantKand the amount of the solute per unit of adsorbent mass necessary to complete the monolayerbwere calculated. The results indicate that MgO is a good adsorbent for nucleobases (adenine > uracil > hypoxantine > cytosine), suggesting a role of metal oxides in concentrating biomolecules in prebiotic conditions that might have favoured the passage from geochemistry to biochemistry.

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The role of accessibility in the characterization of porous solids and their adsorption properties

Adsorption ◽

10.1007/s10450-009-9203-8 ◽

2009 ◽

Vol 16 (1-2) ◽

pp. 3-15 ◽

Cited By ~ 16

Author(s):

D. D. Do ◽

L. Herrera ◽

Chunyan Fan ◽

A. Wongkoblap ◽

D. Nicholson

Keyword(s):

Adsorption Properties ◽

Porous Solids

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On the pH-dependent strontium adsorption by Al-PILCs, impregnated with carboxylate groups of various acid strengths

HNPS Proceedings ◽

10.12681/hnps.2233 ◽

2019 ◽

Vol 11 ◽

Author(s):

C. A. Papachristodoulou ◽

P. A. Assimakopoulos ◽

N-H. J. Gangas

Keyword(s):

Acid Strength ◽

Adsorption Properties ◽

Solution Ph ◽

Cation Uptake ◽

Carboxylate Groups ◽

Constant Ph ◽

Strontium Ions ◽

Ph Dependent ◽

Ph Range

The impregnation of a PILC with carboxylate groups is proposed as a means to improve the adsorption properties of the material for strontium ions. The role of solution pH and carboxylate acid strength in the functionalization of the organic groups is probed by base titrations. In comparing the pristine-PILC with PILCs carrying either oxalate or acetate impregnates, enhanced strontium uptake is evidenced by the modified solids, initiated at pH 6 and 8 in the presence of oxalate and acetate, respectively. The effect on uptake is higher in the former case, amounting to an increase in strontium adsorption by a factor between two and three, depending on the pH range. To further elucidate the significance of the carboxylate acid strength in cation uptake phenomena, strontium adsorption isotherms are presented for PILCs carrying acetate, oxalate, malonate and citrate groups. The results demonstrate that, at constant pH, adsorption increases with increasing acid strength

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Role of the puckered anisotropic surface in the surface and adsorption properties of black phosphorus

Nanoscale ◽

10.1039/c8nr00329g ◽

2018 ◽

Vol 10 (19) ◽

pp. 8979-8988 ◽

Cited By ~ 15

Author(s):

Petr Lazar ◽

Eva Otyepková ◽

Martin Pykal ◽

Klára Čépe ◽

Michal Otyepka

Keyword(s):

Adsorption Properties ◽

Black Phosphorus ◽

Anisotropic Surface

The structure of phosphorene resembles the honeycomb arrangement of graphene, but its layers are buckled and highly anisotropic.

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Metal organic frameworks decorated with free carboxylic acid groups: topology, metal capture and dye adsorption properties

Dalton Transactions ◽

10.1039/d0dt02949a ◽

2020 ◽

Vol 49 (41) ◽

pp. 14690-14705

Author(s):

M. Naqi Ahamad ◽

M. Shahnawaz Khan ◽

M. Shahid ◽

Musheer Ahmad

Keyword(s):

Carboxylic Acid ◽

Metal Organic Frameworks ◽

Dye Adsorption ◽

Adsorption Properties ◽

Carboxylic Acid Groups ◽

Metal Capture ◽

Metal Organic

Elaborating the role of uncoordinated carboxylic acid functions in MOFs in post synthetic modification (PSM) through metal capture and hence in tuning dye adsorption properties.

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Ti4-Decorated B/N-Doped Graphene as High-Capacity Hydrogen Storage Material: A DFT Study

Dalton Transactions ◽

10.1039/d1dt01498f ◽

2021 ◽

Author(s):

Siriporn Jungsuttiwong ◽

Ratchadaree Intayot ◽

Nuttapon Yodsin ◽

Supawadee Namuangruk ◽

Chompoonut Rungnim

Keyword(s):

Density Functional ◽

High Capacity ◽

Adsorption Properties ◽

Hydrogen Storage Material ◽

Storage Material ◽

Binding Properties ◽

Functional Theory ◽

Doped Graphene ◽

Designed Materials

The adsorption properties of the hydrogen atom on our novel-designed materials were investigated using Density functional theory (DFT) calculations, focusing on the role of dopants in modulating the binding properties...

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