scholarly journals Chitosan as a Natural Copolymer with Unique Properties for the Development of Hydrogels

2019 ◽  
Vol 9 (11) ◽  
pp. 2193 ◽  
Author(s):  
Fatma Sami El-banna ◽  
Magdy Elsayed Mahfouz ◽  
Stefano Leporatti ◽  
Maged El-Kemary ◽  
Nemany A. N. Hanafy
Keyword(s):  
Aqueous Solution ◽  
Functional Groups ◽  
Biomedical Application ◽  
Swelling Behavior ◽  
Hydrophilic Polymers ◽  
Physicochemical Mechanism ◽  
And Function

Hydrogel-based polymers are represented by those hydrophilic polymers having functional groups in their chain such as amine (NH2), hydroxyl [-OH], amide (-CONH-, -CONH2), and carboxyl [COOH]. These hydrophilic groups raise their potential to absorb fluids or aqueous solution more than their weights. This physicochemical mechanism leads to increased hydrogel expansion and occupation of larger volume, the process which shows in swelling behavior. With these unique properties, their use for biomedical application has been potentially raised owing also to their biodegradability and biocompatibility. Chitosan as a natural copolymer, presents a subject for hydrogel structures and function. This review aimed to study the structure as well as the function of chitosan and its hydrogel properties.

scholarly journals Simultaneous removal of cationic and anionic dyes from aqueous solution by double functional groups modified bagasse

2020 ◽  
Vol 82 (10) ◽  
pp. 2159-2167
Author(s):  
Ru-yi Zhou ◽  
Jun-xia Yu ◽  
Ru-an Chi
Keyword(s):  
Aqueous Solution ◽  
Functional Groups ◽  
Order Kinetic ◽  
Anionic Dyes ◽  
Adsorption Capacities ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Amine Groups ◽  
Modified Adsorbents ◽  
Zeta Potential Analysis

Abstract Double functional groups modified bagasse (DFMBs), a series of new zwitterionic groups of carboxyl and amine modified adsorbents, were prepared through grafting tetraethylenepentamine (TEPA) onto the pyromellitic dianhydride (PMDA) modified bagasse using the DCC/DMAP method. DFMBs' ability to simultaneously remove basic magenta (BM, cationic dye) and Congo red (CR, anionic dye) from aqueous solution in single and binary dye systems was investigated. FTIR spectra and Zeta potential analysis results showed that PMDA and TEPA were successfully grafted onto the surface of bagasse, and the ratio of the amount of carboxyl groups and amine groups was controlled by the addition of a dosage of TEPA. Adsorption results showed that adsorption capacities of DFMBs for BM decreased while that for CR increased with the increase of the amount of TEPA in both single and binary dye systems, and BM or CR was absorbed on the modified biosorbents was mainly through electrostatic attraction and hydrogen bond. The adsorption for BM and CR could reach equilibrium within 300 min, both processes were fitted well by the pseudo-second-order kinetic model. The cationic and anionic dyes removal experiment in the binary system showed that DMFBs could be chosen as adsorbents to treat wastewater containing different ratios of cationic and anionic dyes.

scholarly journals Effect of synthesis conditions  on  methylene blue adsorption capacity of electrochemically preparated graphene

2020 ◽  
Vol 9 (3) ◽  
pp. 9-14
Author(s):  
Hao Pham Van ◽  
Linh Ha Xuan ◽  
Oanh Phung Thi ◽  
Hong Phan Ngoc ◽  
Huy Nguyen Nhat ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Adsorption Capacity ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Graphene Nanosheets ◽  
Electrochemical Exfoliation ◽  
X Ray ◽  
Synthesis Conditions ◽  
Mb Adsorption

This report presents the effect of synthesis conditions on the synthesis of graphene nanosheets via electrochemical exfoliation method for adsorbing methylene blue from aqueous solution. Oxygen-containing functional groups and defects in the material were characterized by Raman and X-ray photoelectron spectroscopy (XPS). As a result, by using voltage of 15 V, (NH4)2SO4 (5%, 250 mL) and KOH (7.5%, 250 mL), the obtained material showed the highest MB adsorption capacity due to the high densities of oxygen-containing groups and defects comparison to other conditions.

Two physical processes enhanced the performance of Auricularia auricula dreg in Cd(II) adsorption: composting and pyrolysis

2019 ◽  
Vol 79 (8) ◽  
pp. 1511-1526
Author(s):  
Yue Li ◽  
Siqi Huang ◽  
Yingnan Wei ◽  
Xuesheng Liu ◽  
Meng Zhang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Structure ◽  
Functional Groups ◽  
Exchange Capacity ◽  
Bet Surface Area ◽  
Order Kinetic ◽  
Auricularia Auricula ◽  
The Difference ◽  
The Impact ◽  
Crystal Species

Abstract This study aims to discover the impact of composting and pyrolysis on the adsorption performance of Auricularia auricula dreg (AAD) for Cd(II) in aqueous solution. Auricularia auricula dreg (AAD), Auricularia auricula dreg biochar (AADB) and Auricularia auricula dreg compost (AADC) were used to remove Cd(II) from aqueous solution, and their adsorption conditions and mechanisms were compared. The adsorption quantity of three adsorbents reached the maximum (AAD: 80.0 mg/g, AADB: 91.7 mg/g, AADC: 93.5 mg/g) under same conditions (adsorbent dosage of 1 g/L, pH 5.0, biosorption temperature of 25 °C, and biosorption time of 120 min). All Cd(II) biosorption processes onto three adsorbents complied with the Langmuir isotherm model and the pseudo-second-order kinetic equation, and spontaneously occurred in an order of AADC > AADB > AAD. The difference in biosorption quantity relied on variation in surface structure, crystal species and element content caused by composting or pyrolysis. Composting enhanced the changes in surface structure, crystal species, functional groups and ion exchange capacity of the AAD, resulting in AAD had greatly improved the biosorption quantity of Cd(II). Pyrolysis increased the adsorption of Cd(II) mainly by increasing the Brunauer–Emmett–Teller (BET) surface area, the particle size and pH, in the same time, providing more oxygen-containing functional groups.

scholarly journals New Semi-IPN Hydrogels Based on Cellulose for Biomedical Application

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
S. K. Bajpai ◽  
M. P. Swarnkar
Keyword(s):  
Free Radical ◽  
Kinetic Model ◽  
Water Uptake ◽  
Diffusion Coefficients ◽  
Biomedical Application ◽  
Paper Industry ◽  
Swelling Behavior ◽  
Late Time ◽  
Cellulose Pulp ◽  
Uptake Data

Cellulose pulp, obtained from a paper industry, has been dissolved in PEG/NaOH system and the resulting solution has been polymerized in the presence of monomer acrylic acid (AA) and crosslinker N,N′ methylene bisacrylamide via free radical polymerization. The Cell/PEG/poly (SA) ternary semi-IPN hydrogel, so prepared, was characterized by FTIR and TG analysis. The dynamic water uptake of various hydrogels, having different compositions, was investigated in the physiological buffer of pH 7.4 at 37°C. The various hydrogels exhibited chain-relaxation controlled swelling behavior. The uptake data was best interpreted by Schott kinetic model. The various diffusion coefficients, that is, initial (Di), average (Dave), and late time (DL), were also calculated using the dynamic water uptake data. The hydrogels showed fair pH and salt-dependent swelling behavior.

Swelling behavior of poly(acrylamide)/clay nanocomposite hydrogels in acrylamide aqueous solution

2009 ◽  
Vol 112 (1) ◽  
pp. 353-358 ◽  
Author(s):  
Yongmei Jiang ◽  
Meifang Zhu ◽  
Biao Li ◽  
Yang Liu ◽  
Zongyi Qin ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Swelling Behavior ◽  
Nanocomposite Hydrogels ◽  
Poly Acrylamide

scholarly journals Terminal Groups Dependent Near-Field Enhancement Effect of Ti3C2Tx Nanosheets

2020 ◽  
Author(s):  
Ying-Ying Yang ◽  
Wen-Tao Zhou ◽  
Wei-Long Song ◽  
Qing-Quan Zhu ◽  
Hao-Jiang Xiong ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Oxidation Resistance ◽  
Functional Groups ◽  
Near Field ◽  
Field Enhancement ◽  
Electron Injection ◽  
Enhancement Effect ◽  
Hydroxyl Groups ◽  
Physical And Chemical

Abstract Both multilayered (ML) and few-layered (FL) Ti3C2Tx nanosheets with different dominant terminal groups have been prepared through a typical etching and delaminating procedure. Various characterizations confirm that the physical and chemical performance of the nanosheets are dependent on the dominant functional groups. It has been demonstrated that ML-Ti3C2Tx has been mainly terminated by O-related groups, which result in better oxidation resistance and stronger near-field enhancement effect. As for FL-Ti3C2Tx, which is mainly terminated by hydroxyl groups, it can be better dispersed in aqueous solution and could confine stronger near-field after coupling to Ag nanostructures by electron injection.

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