An IGC Study of the Role of Washing Procedures on the Adsorption Properties of Activated Carbons

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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THE ROLE OF SULFONATED ACTIVATED CARBONS AS CATALYSTS FOR THE HYDROLYSIS OF CELLOBIOSE

Brazilian Journal of Chemical Engineering ◽

10.1590/0104-6632.20190361s20170412 ◽

2019 ◽

Vol 36 (1) ◽

pp. 309-315 ◽

Cited By ~ 1

Author(s):

B. Bermejo ◽

A. Couto Fraga ◽

E. F. Sousa-Aguiar

Keyword(s):

Activated Carbons ◽

Hydrolysis Of

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Changes in the Adsorption Properties of Activated Carbon due to Partial Oxidation of the Surface

Adsorption Science & Technology ◽

10.1177/026361749501200305 ◽

1995 ◽

Vol 12 (3) ◽

pp. 211-219 ◽

Cited By ~ 13

Author(s):

A.M. Youssef ◽

A.A. El-Khouly ◽

A.I. Ahmed ◽

E.I. El-Shafey

Keyword(s):

Water Vapour ◽

Surface Coverage ◽

Activated Carbons ◽

Textural Properties ◽

Isosteric Heat ◽

Adsorption Properties ◽

Adsorption Of Water ◽

Oxygen Groups ◽

Initial Adsorption ◽

Entropy Of Adsorption

The textural properties (surface area and porosity) of activated carbons change upon treatment with oxidizing solutions. The extent of this change is related to the strength of the oxidizing agent. Oxidation also changes the chemistry of the surface by forming carbon–oxygen groups which are the sites upon which the initial adsorption of water vapour takes place. The adsorption of water vapour at 300–320 K is mainly physical and the isosteric heat of adsorption decreases continuously as the surface coverage increases. The entropy of adsorption of water vapour on untreated and oxidized carbons, at different adsorption temperatures, has been calculated.

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Role of chemical pre-treatment in the development of super-high surface areas and heteroatom fixation in activated carbons prepared from bagasse

Microporous and Mesoporous Materials ◽

10.1016/j.micromeso.2008.05.020 ◽

2008 ◽

Vol 116 (1-3) ◽

pp. 513-523 ◽

Cited By ~ 15

Author(s):

M. Valix ◽

W.H. Cheung ◽

K. Zhang

Keyword(s):

Activated Carbons ◽

High Surface ◽

Surface Areas ◽

Pre Treatment

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SO2 and NO adsorption properties of activated carbons obtained from a pitch containing iron derivatives

Carbon ◽

10.1016/s0008-6223(01)00035-5 ◽

2001 ◽

Vol 39 (14) ◽

pp. 2173-2179 ◽

Cited By ~ 38

Author(s):

Paolo Davini

Keyword(s):

Activated Carbons ◽

Adsorption Properties ◽

No Adsorption

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Catalytic oxidative desulfurization of a 4,6-DMDBT containing model fuel by metal-free activated carbons: the key role of surface chemistry

Green Chemistry ◽

10.1039/c9gc03234g ◽

2019 ◽

Vol 21 (24) ◽

pp. 6685-6698 ◽

Cited By ~ 10

Author(s):

Zoi Christina Kampouraki ◽

Dimitrios A. Giannakoudakis ◽

Konstantinos S. Triantafyllidis ◽

Eleni A. Deliyanni

Keyword(s):

Surface Chemistry ◽

Activated Carbons ◽

Oxidative Desulfurization ◽

Ambient Conditions ◽

Metal Free ◽

Model Fuel ◽

Catalytic Oxidative Desulfurization

Commercial micro/mesoporous activated carbons were utilized as metal-free catalysts for the desulfurization of a model fuel, i.e. 4,6-dimethyldibenzothiophene (4,6-DMDBT) in hexadecane, under ambient conditions. Oxidation of carbons led to a further catalytic improvement.

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