Ultra-absorbent hybrid hydrogel based on alginate and SiO2 microspheres: A high-water-content system for removal of methylene blue

Panão, Caroline O.; Campos, Eduardo L.S.; Lima, Hugo Henrique Carline de; Rinaldi, Andrelson W.; Lima-Tenório, Michele K.; Tenório‐Neto, Ernandes T.; Guilherme, Marcos R.; Asefa, Tewodros; Rubira, Adley F.

doi:10.1016/j.molliq.2018.11.157

Cited by 47 publications

(18 citation statements)

References 27 publications

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“…Additionally, ether formation through an epoxide ring-opening mechanism was used to prepare covalently cross-linkable alg derivatives with high absorption capacities for water treatment applications [59]. Na-alg was treated with glycidyl-methacrylate (GMA) at pH 10.5 in aqueous media, leading to a nucleophilic attack on both carbon atoms of the epoxide, while this type of reaction under basic conditions is expected to favor the attack at the less hindered position ( Figure 6).…”

Section: Epoxide Ring-opening Reactionsmentioning

confidence: 99%

“…Na-alg was treated with glycidyl-methacrylate (GMA) at pH 10.5 in aqueous media, leading to a nucleophilic attack on both carbon atoms of the epoxide, while this type of reaction under basic conditions is expected to favor the attack at the less hindered position ( Figure 6). GMA-grafted alg derivatives were further covalently cross-linked with vinylated SiO2 MS to produce superabsorbent hybrid hydrogels that showed excellent removal capacity for water samples contaminated with methylene blue [59].…”

Section: Epoxide Ring-opening Reactionsmentioning

confidence: 99%

“…Free radical grafting of Na-alg with vinyl sulfonic acid (VSA) in the presence of the thiourea/peroxydiphosphate system [61] or with polyacrylamide (PAM) under microwave irradiation [62] provided aggregation-promoting agents with biodegradable and eco-friendly properties. GMA-grafted alg derivatives were further covalently cross-linked with vinylated SiO 2 MS to produce superabsorbent hybrid hydrogels that showed excellent removal capacity for water samples contaminated with methylene blue [59].…”

Section: Synthesis Of Graft Copolymersmentioning

confidence: 99%

“…Polymers 2020, 12, x FOR PEER REVIEW 10 of Epoxide ring-opening reactions of sodium alginate with glycidyl-methacrylate (GMA). Adapted from[59].…”

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confidence: 99%

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Strategies to Functionalize the Anionic Biopolymer Na-Alginate without Restricting Its Polyelectrolyte Properties

2020

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The natural anionic polyelectrolyte alginate and its derivatives are of particular interest for pharmaceutical and biomedical applications. Most interesting for such applications are alginate hydrogels, which can be processed into various shapes, self-standing or at surfaces. Increasing efforts are underway to functionalize the alginate macromolecules prior to hydrogel formation in order to overcome the shortcomings of purely ionically cross-linked alginate hydrogels that are hindering the progress of several sophisticated biomedical applications. Particularly promising are derivatives of alginate, which allow simultaneous ionic and covalent cross-linking to improve the physical properties and add biological activity to the hydrogel. This review will report recent progress in alginate modification and functionalization with special focus on synthesis procedures, which completely conserve the ionic functionality of the carboxyl groups along the backbone. Recent advances in analytical techniques and instrumentation supported the goal-directed modification and functionalization.Polymers 2020, 12, 919 2 of 23 Physicochemical and Polyelectrolyte Characteristics of AlginateThe composition, internal structure, and molar mass of the alg backbone govern the functional properties [9]. The solubility of alg in water depends on the pH value and the type of the counterions of the carboxyl groups. At pH < 3, both the M-and G-structures will precipitate as alginic acid. However, alternating M-and G-structures precipitate at lower pH values compared to the alg containing Polymers 2020, 12, 919 3 of 23 more homogeneous block structures. Neutralization of the alginic acid occurs at pH > 4, where it is converted into its corresponding salt [10]. Na-alg is an example of a water-soluble alg.Na-alg behaves in aqueous solution as a typical linear homogeneously charged polyelectrolyte. The chain conformation and consequently the solution viscosity strongly depend on the ionic strength, i.e., on both the alg concentration and the simultaneous presence of low molar mass salt. The intramolecular electrostatic repulsion between the neighboring negatively charged carboxyl groups of each monomer unit forces alg molecules into an extended random coil conformation in aqueous solution [11]. This results in highly viscous solutions even at relatively low alg concentration. The dynamic viscosity increases exponentially with the molar mass, while the intrinsic flexibility of the alg chains in solution increases in the order GG < MM < MG [12]. On the other hand, the selectivity for cation-binding and gel-forming properties strongly depends on the composition and sequence. Divalent cations preferably bind to the G-blocks. The ability to form ionotropic gels is based on this selective binding of cations. Mixing solutions of Na-alg with solutions of cationic polyelectrolytes yields precipitates of polyelectrolyte complexes.The rheological behavior of Na-alg solutions is important for a number of technologies and depends on both the concentration and th...

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Section: Epoxide Ring-opening Reactionsmentioning

confidence: 99%

Section: Epoxide Ring-opening Reactionsmentioning

confidence: 99%

Section: Synthesis Of Graft Copolymersmentioning

confidence: 99%

“…Polymers 2020, 12, x FOR PEER REVIEW 10 of Epoxide ring-opening reactions of sodium alginate with glycidyl-methacrylate (GMA). Adapted from[59].…”

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Strategies to Functionalize the Anionic Biopolymer Na-Alginate without Restricting Its Polyelectrolyte Properties

2020

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“…Thereby, the swelling degree was also tested in distilled water and alginate hydrogel presented higher SD values, whereas carrageenan and pectin hydrogels achieved lower SD values. According to Panão et al, 30 the chemical nature of polymers, such as ionic groups that cause inter-macromolecular electrostatic repulsions, is one of the main contributing factors to a high absorption affinity of water. Hydrogels containing a greater number of ionic groups presented greater capacity of water absorption.…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

Preparation and Delayed Release Study on Pancreatin Encapsulated into Alginate, Carrageenan and Pectin Hydrogels

Olímpio

Mendes

Trevisan

et al. 2020

J. Braz. Chem. Soc.

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In this study, biopolymer-based pH-sensitive hydrogels have been successfully prepared using alginate, κ-carrageenan and pectin aimed at the encapsulation of pancreatin (hydrolytic enzymes like α-amylase, lipase and protease) so as to preserve enzymatic activities. Hydrogels have been characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), swelling degree and swelling profile. Encapsulation efficiency and in vitro studies on delayed release have also been evaluated. All hydrogels presented low swelling degree and enzyme release in a gastric medium. On the other hand, high swelling degree and enzyme release were observed in an intestinal medium. Alginate hydrogel achieved optimal results concerning encapsulation efficiency (18, 68 and 53% for α-amylase, lipase and protease, respectively) and delayed release (363, 7,673 and 17,497 U for α-amylase, lipase and protease, respectively) which has been afterwards compared to a commercial pancreatin formulation (Creon TM 10,000). Thus, it presented better performance than its commercial formulation, mainly in respect of lipase.

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Sodium polyacrylate inhibits fermentative hydrogen production from waste diaper‐like material

Sotelo-Navarro

Poggi‐Varaldo

Turpin-Marion

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND: The inhibitory effect of a moisture-absorbent sodium polyacrylate (SPA), that is commonly used in disposable diapers, on the bio-hydrogen (H 2 ) generation from waste diaper-like material (WDM) was assessed in dark fermentation studies. Three types of treatments were evaluated in batch bioreactors at 37 ∘ C: mixture of bond paper and filter paper (WDM, no SPA), SPA alone (only SPA or control), and WDM spiked with SPA [paper plus sodium polyacrylate hydrogel (WDM-SPA)]. The WDM simulated the cellulosic fraction of diaper composition. RESULTS:The units with only SPA did not produce H 2 . The WDM-SPA units exhibited H 2 production 25% lower than those of bioreactors loaded with only WDM but no SPA. Cumulative H 2 production was 0.03, 4.22 and 5.50 mmolH 2 g TS -1 for the SPA, WDM-SPA and WDM reactors, respectively (0.04, 5.90 and 8.77 mmolH 2 g VS -1 ; 0.89, 132.19 and 196.45 NmLH 2 g VS -1 ). BioH 2 generation was related to predominance of the fermentation route that produces 1 mol L -1 of butyric acid (HBu) plus 2 mol L -1 H 2 in the WDM and WDM-SPA units, as suggested by the ratio A:B (acetic: butyric acids; A:B < 0.79 mg HAc-COD mg HBu-COD -1 in both cases).CONCLUSION: It seems that this is the first documented result on the inhibitory effect of SPA on the bioH2 fermentation of cellulosic wastes. However, further research should be carried out at different levels of SPA to determine, for instance, the half-inhibition value of SPA, that is, the concentration of SPA that would cause a 50% drop in H 2 generation of the non-SPA treatment.

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Ultra-absorbent hybrid hydrogel based on alginate and SiO2 microspheres: A high-water-content system for removal of methylene blue

Cited by 47 publications

References 27 publications

Strategies to Functionalize the Anionic Biopolymer Na-Alginate without Restricting Its Polyelectrolyte Properties

Strategies to Functionalize the Anionic Biopolymer Na-Alginate without Restricting Its Polyelectrolyte Properties

Preparation and Delayed Release Study on Pancreatin Encapsulated into Alginate, Carrageenan and Pectin Hydrogels

Sodium polyacrylate inhibits fermentative hydrogen production from waste diaper‐like material

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