scholarly journals Modular Chitosan-Based Adsorbents for Tunable Uptake of Sulfate from Water

2020 ◽  
Vol 21 (19) ◽  
pp. 7130 ◽  
Author(s):  
Bernd G. K. Steiger ◽  
Lee D. Wilson
Keyword(s):  
Technology Development ◽  
Saline Water ◽  
Adsorption Properties ◽  
Point Of Zero Charge ◽  
Cross Linking ◽  
Synthetic Approach ◽  
Sulfate Uptake ◽  
Sulfate Adsorption ◽  
Adsorption Desorption ◽  
Inorganic Sulfate

The context of this study responds to the need for sorbent technology development to address the controlled removal of inorganic sulfate (SO42−) from saline water and the promising potential of chitosan as a carrier system for organosulfates in pharmaceutical and nutraceutical applications. This study aims to address the controlled removal of sulfate using chitosan as a sustainable biopolymer platform, where a modular synthetic approach was used for chitosan bead preparation that displays tunable sulfate uptake. The beads were prepared via phase-inversion synthesis, followed by cross-linking with glutaraldehyde, and impregnation of Ca2+ ions. The sulfate adsorption properties of the beads were studied at pH 5 and variable sulfate levels (50–1000 ppm), where beads with low cross-linking showed moderate sulfate uptake (35 mg/g), while cross-linked beads imbibed with Ca2+ had greater sulfate adsorption (140 mg/g). Bead stability, adsorption properties, and the point-of-zero charge (PZC) from 6.5 to 6.8 were found to depend on the cross-linking ratio and the presence of Ca2+. The beads were regenerated over multiple adsorption-desorption cycles to demonstrate the favorable uptake properties and bead stability. This study contributes to the development of chitosan-based adsorbent technology via a modular materials design strategy for the controlled removal of sulfate. The results of this study are relevant to diverse pharmaceutical and nutraceutical applications that range from the controlled removal of dextran sulfate from water to the controlled release of chondroitin sulfate.

scholarly journals Uptake of Methylene Blue from Aqueous Solution by Pectin–Chitosan Binary Composites

2020 ◽  
Vol 4 (3) ◽  
pp. 95
Author(s):  
Dexu Kong ◽  
Lee D. Wilson
Keyword(s):  
Methylene Blue ◽  
Aqueous Media ◽  
Dye Adsorption ◽  
Adsorption Properties ◽  
Point Of Zero Charge ◽  
Cross Linking ◽  
Gravimetric Analysis ◽  
Adsorption Sites ◽  
Biopolymer Composites

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.

scholarly journals ADSORPTION PROPERTIES OF TITANIA-SILICA MEMBRANES OBTAINED ON CERAMIC SUBSTRАTE

2018 ◽  
Vol 54 (3) ◽  
pp. 274-280
Author(s):  
T. F. Kouznetsova ◽  
A. I. Ivanets ◽  
J. D. Sauka
Keyword(s):  
Surface Area ◽  
Quartz Substrate ◽  
Cetylpyridinium Chloride ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Adsorption Properties ◽  
Molar Ratio ◽  
Silica Membranes ◽  
Metal Silicate ◽  
Adsorption Desorption

Titania-silica membranes on a porous quartz substrate are prepared by its direct contact with metal silicate sol at various Ti/Si ratios in the conditions of coagel sedimentation and presence of cetylpyridinium chloride. The study of textural and adsorption properties of membranes is conducted by low-temperature nitrogen adsorption-desorption, including methods of t-plots and DFT theory. It was shown that obtained membranes have mesoporous structure with the specific surface area and pore hydraulic diameter varied in intervals of 64–217 m2 /g and 4–11 nm, respectively. Developed values of surface area remain up to molar ratio of Ti/Si = 50/50.

Effects of chitosan modification, cross-linking, and oxidation on the structure, thermal stability, and adsorption properties of porous maize starch

2021 ◽  
pp. 107288
Author(s):  
Xiuying Han ◽  
Huiliang Wen ◽  
Yu Luo ◽  
Jun Yang ◽  
Wenhao Xiao ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Adsorption Properties ◽  
Cross Linking ◽  
Maize Starch

scholarly journals Efficient adsorption of Hg(II) from aqueous solution by N, S co-doped MnFe2O4@C magnetic nanoparticles

2020 ◽  
Vol 81 (6) ◽  
pp. 1273-1282 ◽  
Author(s):  
Hangdao Qin ◽  
Hao Cheng ◽  
Chenggui Long ◽  
Xiaogang Wu ◽  
Yanhong Chen ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Chemical Properties ◽  
Point Of Zero Charge ◽  
Simple Method ◽  
Transmission Electron ◽  
Pseudo Second Order ◽  
Enhanced Adsorption ◽  
Adsorption Desorption ◽  
Physical And Chemical ◽  
Co Doped

Abstract N, S co-doped MnFe2O4@C magnetic nanoparticles were successfully synthesized by a simple method involving the preparation of MnFe2O4 nanoparticles and subsequent pyrolysis treatment. The physical and chemical properties of MnFe2O4, MnFe2O4@C and MnFe2O4@C–NS nanoparticles were characterized by X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), N2 adsorption–desorption and the pH at the point of zero charge. Their performances in the adsorption of Hg(II) from water were investigated. The adsorption process followed pseudo-second-order kinetics and the experimental data of equilibrium isotherms fitted well with the Langmuir model. MnFe2O4@C–NS showed the highest adsorption capacity of 108.56 mg/g, increasing more than 1.7 times compared to MnFe2O4. The enhanced adsorption performance was attributed to the larger specific surface area as well as the complexation of N and S ligands on the surface. The thermodynamic parameters of ΔH°, ΔS° and ΔG° at 30 °C were −24.39 kJ/mol, −0.046 kJ/mol K and −10.45 kJ/mol, respectively, which indicated that the adsorption of Hg(II) on MnFe2O4@C–NS was exothermic and spontaneous in nature. Moreover, MnFe2O4@C–NS showed superior selectivity towards Hg(II) compared with other metal ions generally present in mercury-containing industrial wastewater.

Acid Precipitation and Soil Sulfate Adsorption Properties in a Tropical and in a Temperate Forest Soil

Biotropica ◽  
1979 ◽  
Vol 11 (1) ◽  
pp. 38 ◽  
Author(s):  
D. W. Johnson ◽  
D. W. Cole ◽  
S. P. Gessel
Keyword(s):  
Forest Soil ◽  
Temperate Forest ◽  
Acid Precipitation ◽  
Adsorption Properties ◽  
Sulfate Adsorption

Monodisperse cross-linked polystyrene nanospheres by emulsifier-free miniemulsion polymerization

e-Polymers ◽  
2015 ◽  
Vol 15 (4) ◽  
pp. 263-270 ◽  
Author(s):  
Kai Liang ◽  
Qingquan Liu ◽  
Meixuan Peng
Keyword(s):  
Particle Surface ◽  
Miniemulsion Polymerization ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Weight Percent ◽  
Water Soluble ◽  
Cross Linking ◽  
Simple Route ◽  
Polystyrene Nanospheres ◽  
Adsorption Desorption

AbstractCross-linked cationic polystyrene (CCPS) nanospheres with monodispersity were successfully generated by soap-free miniemulsion polymerization of styrene and divinylbenzene with 2,2′-azobis (2-amidinopropane) dihydrochloride as a water-soluble initiator. The effects of output power of the homogenizer and the concentration of the initiator and cross-linking agent on the particle size and coefficient of variation of CCPS nanospheres were systematically investigated and discussed. The weight percent of N element on the particle surface and the ζ potential were determined as different initiator concentrations were employed for the preparation of CCPS nanospheres. Furthermore, the technique of nitrogen adsorption/desorption was applied to characterize the specific surface area and the total pore volume of the CCPS nanospheres, which were generated from different amounts of divinylbenzene. Overall, the present study provides a simple route for producing cross-linked polymer nanospheres with monodispersity.

Geometric, Magnetic, and Adsorption Properties of Cross-Linking Carbon Nanotubes: A Computational Study

2013 ◽  
Vol 117 (7) ◽  
pp. 3646-3652 ◽  
Author(s):  
Jianhua Wu ◽  
Anahita Ayasoufi ◽  
Jerzy Leszczynski ◽  
Frank Hagelberg
Keyword(s):  
Carbon Nanotubes ◽  
Computational Study ◽  
Adsorption Properties ◽  
Cross Linking

scholarly journals Preparation of GO/MIL-101(Fe,Cu) composite and its adsorption mechanisms for phosphate in aqueous solution

2021 ◽  
Author(s):  
You Wu ◽  
Zuannian Liu ◽  
Bakhtari Mohammad Fahim ◽  
Junnan Luo
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Adsorption Mechanism ◽  
Nitrogen Adsorption ◽  
Adsorption Properties ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Mechanisms ◽  
Adsorption Desorption

Abstract In this study, MIL-101(Fe), MIL-101(Fe,Cu), and Graphene Oxide (GO) /MIL-101(Fe,Cu) were synthesized to compose a novel sorbent. The adsorption properties of these three MOFs-based composites were compared toward the removal of phosphate. Furthermore, the influencing factors including reaction time, pH, temperature and initial concentration on the adsorption capacity of phosphate on these materials as well as the reusability of the material were discussed. The structure of fabricated materials and the removal mechanism of phosphate on the composite material were analyzed by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analysis and zeta potential. The results show that the maximum adsorption capacity of phosphate by the composite GO/MIL-101(Fe,Cu)-2% was 204.60 mg·g− 1, which is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe). likewise the specific surface area of GO/MIL-101(Fe,Cu)-2% is 778.11 m2/g is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe),which are 747.75 and 510.66m2/g respectively. The adsorption mechanism of phosphate is electrostatic attraction, form coordination bonds and hydrogen bonds. The fabricated material is a promising adsorbent for the removal of phosphate with good reusability.

scholarly journals Preparation and application of polyethyleneimine-modified corncob magnetic gel for removal of Pb(ii) and Cu(ii) ions from aqueous solution

RSC Advances ◽  
2022 ◽  
Vol 12 (4) ◽  
pp. 1950-1960
Author(s):  
Zhi Chen ◽  
Jun Zeng ◽  
Zhi-Bo Zhang ◽  
Zhi-Jie Zhang ◽  
Shan Ma ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Adsorption Properties ◽  
Cross Linking ◽  
Modified Chitosan

A kind of magnetic gel material was synthesized by cross-linking PEI modified chitosan and corncob biomass with good adsorption properties of heavy metal ions.

scholarly journals Magnetically Functionalized Moss Biomass as Biosorbent for Efficient Co2+ Ions and Thioflavin T Removal

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3619 ◽  
Author(s):  
Martin Pipíška ◽  
Simona Zarodňanská ◽  
Miroslav Horník ◽  
Libor Ďuriška ◽  
Marián Holub ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Adsorption Properties ◽  
Thioflavin T ◽  
Oxide Nanoparticles ◽  
High Adsorption ◽  
Efficient Removal ◽  
High Adsorption Capacity ◽  
Rapid Kinetics ◽  
Adsorption Desorption ◽  
Rhytidiadelphus Squarrosus

Microwave synthesized iron oxide nanoparticles and microparticles were used to prepare a magnetically responsive biosorbent from Rhytidiadelphus squarrosus moss for the rapid and efficient removal of Co2+ ions and thioflavin T (TT). The biocomposite was extensively characterized using Fourier transformed infrared (FTIR), XRD, SEM, and EDX techniques. The magnetic biocomposite showed very good adsorption properties toward Co2+ ions and TT e.g., rapid kinetics, high adsorption capacity (218 μmol g−1 for Co and 483 μmol g−1 for TT), fast magnetic separation, and good reusability in four successive adsorption–desorption cycles. Besides the electrostatic attraction between the oxygen functional moieties of the biomass surface and both Co2+ and TT ions, synergistic interaction with the –FeOH groups of iron oxides also participates in adsorption. The obtained results indicate that the magnetically responsive biocomposite can be a suitable, easily separable, and recyclable biosorbent for water purification.

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