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1.
Int J Phytoremediation ; : 1-12, 2024 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-39460565

RESUMO

The synthesis of catalysts has gained specific concern due to their versatile applications in particular azo dye decolorization. In the current work, metallic nanoparticles (copper and silver) were In-situ biosynthesised using Allium sativum and Chondrilla juncea extract. The obtained Allium-copper oxide and Allium-silver oxide materials were analyzed using SEM, TEM, FT-IR, TGA-DTG, SEM, TEM, and XRD techniques. Allium peels had a rough surface, with nanoparticles equally distributed over it. The crystal structure of Allium peels was altered after the addition of CuO and AgO nanoparticles. The highest residual mass values in the prepared materials indicated that the metallic nanoparticles were, in situ, formed. The prepared materials had worse thermal stability than Allium peel powders. The azo dyes, Calmagite and Naphthol Blue Black B were tested in the catalytic power of the resulting materials. The decolorization process was affected by the dye structure, amount of H2O2, dye concentration, time of reaction, and temperature of the bath. The activation energy values for Allium-CuO were 18.44 kJ mol-1 for calmagite, and 23.28 kJ mol-1 for naphthol blue black, respectively. Nevertheless, the energy values for Allium-AgO were 50.01 kJ mol-1 for calmagite and 12.44 kJ mol-1 for Naphthol blue black. The calculated low energy values for the prepared materials suggested the high efficiency of the use of these catalysts in azo dye decolorization under the change of some main experimental conditions.


Chondrilla juncea was employed as a biological extract for in-situ reduction of copper and silver ions within Allium sativum peels. The resulting Allium sativum-CuO and Allium sativum -AgO materials were used as efficient catalysts for azo dye decolorization.

2.
Polymers (Basel) ; 16(12)2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38932011

RESUMO

Nanomaterials have attracted specific consideration due to their specific characteristics and uses in several promising fields. In the present study, Chondrilla juncea was employed as a biological extract to facilitate the reduction of copper and silver ions within garlic peel powders. The resulting garlic-CuO and garlic-AgO nanocomposites were characterized using several analytical methods including FTIR, TGA/DTG, SEM, TEM, and XRD analyses. The garlic peel exhibited a rough surface. The nanoparticles were evenly dispersed across its surface. The incorporation of CuO and AgO nanoparticles affected the crystal structure of garlic peel. The establishment of CuO and AgO nanoparticles was evidenced by the highest residual mass values observed for the prepared nanocomposites. The thermogravimetric analysis showed that the prepared nanocomposites had lower thermal stability compared with garlic peel powders. The prepared nanocomposites were used for catalytic degradation of naphthol blue black B and calmagite. The decolorization process depended on the quantity of H2O2, initial concentration of azo dyes, duration of contact, and temperature of the bath. The calculated activation energy (Ea) values for the garlic-CuO nanocomposites were found to be 18.44 kJ mol-1 and 23.28 kJ mol-1 for calmagite and naphthol solutions, respectively. However, those calculated for garlic-AgO nanocomposites were found to be 50.01 kJ mol-1 and 12.44 kJ mol-1 for calmagite and naphthol, respectively.

3.
Heliyon ; 10(4): e26364, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38420384

RESUMO

The key solution to combat trace metal pollution and keep the environment, ecosystem, animals, and humans safe is earlier and rapid trace metal detection. For all these reasons, we propose in this work the design of a simple electrochemical sensor functionalized with green nanoparticles for electrochemical detection of the fourth most dangerous heavy metal ions namely copper, zinc, lead, and mercury. The green nanoparticles are fabricated by a one-step, consisting of reducing platinum nanoparticles by a natural gum Arabic polymer. To guarantee the success of these nanoparticles' design, the nanoparticles have been characterized by Fourier-transform infrared spectroscopy FTIR, and thermogravimetric TGA techniques. While, for the electrochemical characterization, we have adopted cyclic voltammetry CV and electrochemical impedance spectroscopy EIS to control different steps of surface modification, and the differential pulse anodic stripping DPAS was monitored to follow up the electrochemical detection of different heavy metals. Results: have confirmed the good chemical and physical properties of the elaborated nanoparticles. As, the developed sensor showed a specific electrochemical response toward the heavy metal ions separately, with a lower limit of detection lower LOD than that recommended by the World Health Organization, in order of 9.6 ppb for Cu2+, 1.9 ppb for Zn2+, 0.9 ppb for Hg2+, and 4.2 ppb for Pb2+. Impressively, the elaborated sensor has demonstrated also high stability, outstanding sensitivity, and excellent analytical performance.In addition, the elaborated analytical tool has been successfully applied to the determination of various heavy metal ions in real samples, reflecting then its promising prospect in practical application.

5.
RSC Adv ; 13(27): 18382-18395, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-37342813

RESUMO

A highly selective and ultra-sensitive electrochemical sensing probe was proposed by combining sulfated-carboxymethyl cellulose (CMC-S) and a functionalized-multiwalled carbon nanotube (f-MWNT) nano-composite with high conductivity and durability. The CMC-S/MWNT nanocomposite was impregnated on a glassy carbon electrode (GCE) to construct the non-enzymatic and mediator-free electrochemical sensing probe for trace detection of As(iii) ions. The fabricated CMC-S/MWNT nanocomposite was characterized by FTIR, SEM, TEM, and XPS. Under the optimized experimental conditions, the sensor exhibited the lowest detection limit of 0.024 nM, a high sensitivity (69.93 µA nM-1 cm-2) with a good linear relationship in the range of 0.2-90 nM As(iii) concentration. The sensor demonstrated strong repeatability, with the current response continuing at 84.52% after 28 days of use, in addition to good selectivity for the determination of As(iii). Additionally, with recovery ranging from 97.2% to 107.2%, the sensor demonstrated comparable sensing capability in tap water, sewage water, and mixed fruit juice. The electrochemical sensor for detecting trace levels of As(iii) in actual samples is anticipated to be produced by this effort and is expected to possess great selectivity, good stability, and sensitivity.

6.
Polymers (Basel) ; 15(4)2023 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-36850313

RESUMO

In this work, pectin biopolymers were functionalized with dichloride (5,10,15,20-tetraphenylporphyrinato) antimony [Sb(TPP)Cl2] at various compositions (0.5%, 1%, and 2%). The prepared compounds were characterized with several analytical methods, including X-ray fluorescence (XRF) spectrometry, Fourier-transform infrared spectroscopy (FT-IR), electrospray ionization mass spectrometry (EIS), scanning electron microscope (SEM), X-ray diffraction (XRD), and thermogravimetric-differential thermal (TGA/DTG) analysis. The XRF technique evidenced the presence of Sb metal in the composite beads. FT-IR suggested that the interaction between pectin and the [Sb(TPP)Cl2] complex was assured by inter- and intramolecular C-H⋯O, C-H⋯Cl hydrogen bonds and weak C-H⋯Cg π interactions (Cg is the centroid of the pyrrole and phenyl rings). The morphological features of the prepared polymeric beads were affected by the addition of [Sb(TPP)Cl2] particles, and the surface became rough. The thermal residual mass for the composite beads (29%) was more important than that of plain beads (23%), which confirmed the presence of inorganic matter in the modified polymeric beads. At 20 °C, the highest adsorption amounts of methylene blue were 39 mg/g and 68 mg/g for unmodified pectin and pectin-[Sb(TPP)Cl2] beads, respectively. The adsorption mechanism correlated well with the kinetic equation of the second order and the isotherm of Freundlich. The prepared polymeric beads were characterized as moderate-to-good adsorbents. The calculated thermodynamic parameters demonstrated an exothermic and thermodynamically nonspontaneous mechanism.

7.
Int J Biol Macromol ; 229: 210-223, 2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36592846

RESUMO

Functionalization and various applications of biomaterials have progressively gained a major interest due to the cost-effectiveness, renewability, and biodegradability of these substrates. The current work focalized on the functionalization of microcrystalline cellulose with polyethyleneimine solution (3 %, 5 %, and 10 %) and hydrazine sulfate salt (1:1, 1:2, 2:1) using an impregnation method. Untreated and treated samples were characterized using FT-IR, SEM, XRD, TGA, and DTA analyses. The crystallinity index values for control microcrystalline cellulose, cellulose-polyethyleneimine, and cellulose-hydrazine were 57.13.8 %, 57.29 %, and 52.62 %, respectively. Cellulose-polyethyleneimine (5 %) and cellulose-hydrazine (1:1) displayed the highest adsorption capacities for calmagite (an anionic dye). At equilibrium, the maximum adsorption capacities for calmagite achieved 104 mg/g for cellulose-polyethyleneimine (5 %), 45 mg/g for cellulose-hydrazine (1:1), and only 12.4 mg/g for untreated cellulose. Adsorption kinetics complied well with the pseudo-second-order kinetic model. The adsorption isotherm fitted well with the Langmuir isotherm. Overall, the functionalized cellulosic samples could be considered potential materials for the treatment of contaminated waters.


Assuntos
Corantes , Poluentes Químicos da Água , Corantes/química , Polietilenoimina/química , Espectroscopia de Infravermelho com Transformada de Fourier , Adsorção , Celulose/química , Hidrazinas , Poluentes Químicos da Água/química , Cinética , Concentração de Íons de Hidrogênio
8.
Int J Phytoremediation ; 25(10): 1359-1370, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36576064

RESUMO

Ligno-cellulosic biomasses had been recognized for their potential use to produce chemicals and biomaterials. The current study focused on the use of a new cellulosic Robinia Pseudoacacia fiber and extracted lignin as adsorbents for methylene blue (a cationic dye). The biomaterials were analyzed using FT-IR spectroscopy, SEM, XRD, and TGA-DTA techniques. The surface of Robinia fibers was rough and porous. The crystallinity index (CrI) value for Robinia fibers was found to be 32%. The ability of the studied samples to remove methylene blue from water was assessed under the variation of time, pH, dye concentration, temperature, and NaCl concentration. The maximum adsorption capacity of methylene blue reached 191 mg/g for Robinia fibers and it achieved 22 mg/g for the extracted lignin (T = 20 °C, pH = 6, and time = 90 min). The adsorption data complied with the pseudo second-order kinetic model and both Langmuir and Freundlich isotherms. Based on these findings, the process suggested the occurrence of many physicochemical interactions between methylene blue molecules and the studied biomaterials. The adsorption mechanism was exothermic, non-spontaneous, and it was described by the decrease of the disorder. Adsorption results proved that Robinia fiber was an attractive candidate for the removal of cationic dyes from water.


A low-cost and abundant Robinia Pseudoacacia fiber and its extracted lignin are characterized and further studied as adsorbents for cationic dyes under the change of the experimental conditions.


Assuntos
Robinia , Poluentes Químicos da Água , Água , Lignina/química , Azul de Metileno/análise , Azul de Metileno/química , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio , Biodegradação Ambiental , Corantes/química , Adsorção , Cinética
9.
Int J Biol Macromol ; 226: 956-964, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36529210

RESUMO

The green synthesis of nanoparticles using biogenic approaches constitutes a challenge for effective applications. The massive aliphatic hydroxyl groups of lignin exhibited excellent reduction properties allowing the production of metallic nanoparticles. In this work, alkali lignin was extracted from virgin populus tremula and used for the preparation of copper oxide nanoparticles. The analysis of the prepared nanoparticles was assessed using Fourier Transform Infra-red (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), and Transmission Electron Microscopy (TEM). FT-IR results displayed that different phytochemicals constituents of lignin extract were responsible for the production of CuO nanoparticles. XRD information demonstrated monoclinic CuO nanoparticles with a mean size of 12.4 nm. SEM images showed that some nanoparticles were quite separated from each other and some of them were agglomerated due to the oxidation of metal nanoparticles. TEM photos indicated that the overlap of the nanoparticles resulted in rectangular patterns due to the presence of lignin on the surface of CuO nanoparticles. Finally, the prepared CuO nanoparticles were applied for the removal of methylene blue from water. The results showed that the maximum adsorption capacity reached 85 mg/g at the following conditions: T = 20 °C, pH = 6, and time = 60 min.


Assuntos
Nanopartículas Metálicas , Populus , Lignina/química , Cobre/química , Azul de Metileno/química , Álcalis , Espectroscopia de Infravermelho com Transformada de Fourier , Nanopartículas Metálicas/química , Óxidos
10.
Int J Biol Macromol ; 202: 161-176, 2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35045344

RESUMO

Chemical modification of a biopolymer offers a simple strategy to realize new materials with added benefits. In this paper, meso-tetrakis(2,4,6-trimethylphenyl) porphyrinto) zinc(II) supported sodium alginate gel beads were successfully prepared, characterized, and used for the removal of a cationic dye from aqueous solution. The chemical structure of the prepared composite beads was confirmed by FT-IR, SEM, XRD and TGA/DTG techniques. Analytical data suggested that the sodium alginate beads and meso-tetrakis(2,4,6-trimethylphenyl) porphyrinto) zinc(II) complex interacted via non-covalent interaction (H-bonding) mode. The morphological micrographs showed spherical and smooth composite beads. The crosslinking of hydroxyl and carboxylate groups of the biopolymer with calcium ions and the incorporation of meso-tetrakis(2,4,6-trimethylphenyl) porphyrinto) zinc(II) into alginate matrix resulted in a small decrease of residual mass. The maximum adsorption capacities of methylene blue, at 20 °C, were found to be 52.3 mg/g and 34.8 mg/g for sodium alginate composite beads (3%) and plain sodium alginate beads, respectively. The adsorption process followed Freundlich isotherm and pseudo second order kinetics. The thermodynamic study displayed an exothermic and non-spontaneous process.


Assuntos
Azul de Metileno , Poluentes Químicos da Água , Adsorção , Alginatos/química , Concentração de Íons de Hidrogênio , Cinética , Azul de Metileno/química , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/química , Zinco
11.
Int J Phytoremediation ; 24(2): 118-130, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34043917

RESUMO

In this investigation, Pergularia tomentosa leaves were used as a promising source of bioproducts for the reduction of copper sulfate into copper oxide nanoparticles. The prepared nanoparticles were characterized using Fourier-transform infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), and Thermogravimetric analysis (TGA). FI-IR showed the presence of hydroxyl, ester, and aromatic groups, which are characteristics of phenolics and other bioproducts. SEM features exhibited spherical and agglomerated particles. In EDX data, the peak at 1 Kev, is an index of metallic nanoparticles of copper. The signals related to C and O peaks indicated the presence of phytochemicals in the studied extract. The synthesized copper oxide nanoparticles had a face-centered cubic structure. The size of the nanoparticles varied from 1.7 to 15.2 nm. The adsorption capacity of methylene blue using copper oxide nanoparticles reached 93.2 mg/g (pH = 6, T = 22 °C, adsorbent dose = 0.0125 g). Additionally, methylene blue solution was completely decolorized after 2 min of reaction (pH = 6, 0.0057 mg NaBH4, C0 = 10 mg/L, catalyst = 0.005 g). NOVELTY STATEMENTIn this study, Pergularia tomentosa leaves were used, for the first time, as a biomaterial rich in bioproducts for the reduction of copper sulfate into copper oxide nanoparticles. The prepared particles act as promising materials for the decolorization of contaminated water via both adsorption and degradation processes.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Biodegradação Ambiental , Cobre , Óxidos , Folhas de Planta , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
12.
Polymers (Basel) ; 13(19)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34641149

RESUMO

Cellulose is the most widely available biopolymer which is extensively used for several applications including textiles, composites, pharmaceutical, water treatment, etc. In this investigation, cellulose was chemically extracted from Populus tremula seed fibers. Samples were characterized using FT-IR, SEM, XRD, and TGA-DTA analyses. FT-IR spectrum of the extracted cellulose confirmed that hemicellulose and lignin were removed during alkali and bleaching treatments. SEM images showed the partially roughened surface of the fiber due to the removal of non-cellulosic elements and surface impurities during chemical modification. The crystallinity index values for untreated Populus tremula fibers and extracted cellulose were calculated to be 32.8% and 58.9%, respectively. The obvious increase in the crystallinity index for the extracted cellulose confirmed the removal of amorphous compounds present in raw populus. Alkali-treated populus fibers were more thermally stable than raw fibers. All changes observed after alkali and bleaching treatments evidenced the removal of amorphous contents and non-cellulosic components in raw populus fibers. Extracted cellulose exhibited excellent adsorption capacities of methylene blue (140.4 mg g-1) and crystal violet (154 mg g-1). The pseudo second order equation fitted well the kinetic data indicating a chemi-sorption process. The Freundlich model complied well with the experimental data suggesting that the adsorption of the studied dyes was multilayer.

13.
Beilstein J Org Chem ; 17: 2450-2461, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34630725

RESUMO

A facile synthesis of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridine derivatives is reported which is based on POCl3-mediated cyclodehydration followed by double Suzuki-Miyaura cross-coupling. The absorption and fluorescence properties of the obtained products were investigated and their HOMO/LUMO energy levels were estimated by cyclic voltammetry measurements. Besides, density functional theory calculations were carried out for further exploration of their electronic properties.

14.
Beilstein J Org Chem ; 17: 1629-1640, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34354771

RESUMO

Acridine derivatives have attracted considerable interest in numerous areas owing to their attractive physical and chemical properties. Herein, starting from readily available anthranilic acid, an efficient synthesis of 2,4-bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridine derivatives was accomplished via a one-pot double Sonogashira cross-coupling method. The UV-visible absorption and emission properties of the synthesized molecules have been examined. Additionally, theoretical studies based on density functional theory (DFT/B3LYP/6-31G(d)) were carried out.

15.
Carbohydr Polym ; 261: 117908, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33766384

RESUMO

In this study, copper oxide nanoparticles, prepared using pistacia vera hull extract, were immobilized onto chitosan. FT-IR spectrum of copper oxide-chitosan exhibited chemical shifting of the main peaks of the biopolymer indicating that hydroxyl and amino groups were reacted with copper oxide nanoparticles. SEM features showed spherical surface and physical stability of the composite. The shifting of the burning temperature in DTA from 278.5 °C to 212.6 °C in the composite proved the interaction between chitosan and copper oxide nanoparticles. The composite was applied for the oxidative degradation of naphthol blue black in the presence of H2O2. The change of copper oxide nanoparticles loading, time, dye concentration, temperature, and oxidant dose were studied. The degradation yield reached 86 % (C0 = 30 mg/L, T=20 °C, H2O2 = 8 mL/L). The activation energy (Ea), entropy (ΔS*) and enthalpy (ΔH*) were equal to 45.558 KJ. mol-1, -116.203 J mol-1 K-1 and 42.986 kJ mol-1, respectively.

16.
Polymers (Basel) ; 13(3)2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33525384

RESUMO

The current study highlights a novel bio-sorbent design based on polyelectrolyte multi-layers (PEM) biopolymeric material. First layer was composed of sodium alginate and the second was constituted of citric acid and k-carrageenan. The PEM system was crosslinked to non-woven cellulosic textile material. Resulting materials were characterized using FT-IR, SEM, and thermal analysis (TGA and DTA). FT-IR analysis confirmed chemical interconnection of PEM bio-sorbent system. SEM features indicated that the microspaces between fibers were filled with layers of functionalizing polymers. PEM exhibited higher surface roughness compared to virgin sample. This modification of the surface morphology confirmed the stability and the effectiveness of the grafting method. Virgin cellulosic sample decomposed at 370 °C. However, PEM samples decomposed at 250 °C and 370 °C, which were attributed to the thermal decomposition of crosslinked sodium alginate and k-carrageenan and cellulose, respectively. The bio-sorbent performances were evaluated under different experimental conditions including pH, time, temperature, and initial dye concentration. The maximum adsorbed amounts of methylene blue are 124.4 mg/g and 522.4 mg/g for the untreated and grafted materials, respectively. The improvement in dye sorption evidenced the grafting of carboxylate and sulfonate groups onto cellulose surface. Adsorption process complied well with pseudo-first-order and Langmuir equations.

17.
Int J Phytoremediation ; 23(10): 1085-1094, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33511852

RESUMO

In this work, powdered Calotropis gigantea seedpods were characterized and used as biosorbents of methylene blue dye from aqueous solution. FT-IR spectroscopy demonstrated functional groups characteristics of cellulose. Steric exclusion chromatography donated an average molecular weight of 230 kg/mol of the biopolymer. The polymolecularity index value (1.95) proved the good homogeneity of the polysaccharide. Scanning electron microscopy features displayed a homogenous morphology and porous structure. X-ray diffraction patterns showed peaks characteristics of cellulose and non-cellulose compositions. Thermogravimetric analysis/differential thermal analysis displayed exothermal decompositions at 316.9 °C and 456 °C. The maximum biosorption capacity of methylene blue was 88.36 mg/g at pH = 6, time = 60 min, and T = 21 °C. The level was comparable to some other studied agricultural wastes. The adsorption mechanism followed pseudo-second-order and Freundlich models. As it is abundant, available, low-cost, and easily recovered from solution, C. gigantea seedpods could be used as an effective biomaterial for the removal of organic pollutants from contaminated waters. Novelty statement: An abundant, available, and low-cost Calotropis gigantea seedpod was used, for the first time, as an effective biomaterial for the biosorption of organic pollutants. The biosorption level was found to be comparable to some other agricultural wastes studied previously in the literature.


Assuntos
Calotropis , Poluentes Químicos da Água , Adsorção , Biodegradação Ambiental , Concentração de Íons de Hidrogênio , Cinética , Azul de Metileno , Sementes , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Poluentes Químicos da Água/análise
18.
Polymers (Basel) ; 12(11)2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33142972

RESUMO

Cellulose substrate waste has demonstrated great potential as a biosorbent of pollutants from contaminated water. In this study, Neriumoleander fruit, an agricultural waste biomaterial, was used for the biosorption of methylene blue from synthetic solution. Fourier-transform infrared (FTIR) spectroscopy indicated the presence of the main absorption peak characteristics of cellulose, hemicellulose, and lignin compositions. X-ray diffraction (XRD) pattern exhibited peaks at 2θ = 14.9° and 2θ = 22°, which are characteristics of cellulose I. Scanning electron microscopy (SEM) showed a rough and heterogeneous surface intercepted by some cavities. Thermogravimetric analysis (TGA) showed more than a thermal decomposition point, suggesting that Nerium fruit is composed of cellulose and noncellulosic matters. The pHpzc value of Nerium surface was experimentally determined to be 6.2. Nerium dosage, pH, contact time, dye concentration, and temperature significantly affected the adsorption capacity. The adsorption capacity reached 259 mg/g at 19 °C. The mean free energy ranged from 74.53 to 84.52 KJ mol-1, suggesting a chemisorption process. Thermodynamic parameters define a chemical, exothermic, and nonspontaneous mechanism. The above data suggest that Nerium fruit can be used as an excellent biomaterial for practical purification of water without the need to impart chemical functionalization on its surface.

19.
Int J Biol Macromol ; 153: 305-316, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32126203

RESUMO

The functionalization of polymers is still an efficient scheme to provide materials with new properties. In this paper, 4-methyl-2-(naphthalen-2-yl)-N-propylpentanamide-functionalized ethoxy-silica was successfully immobilized onto chitosan bio-polymer spherical beads to improve their adsorption characteristics. The interaction between the polymer and the functionalized silica was analyzed using FT-IR spectroscopy and SEM analysis. FT-IR investigation suggested that the interaction between chitosan and functionalized silica occurred through hydrogen bonding. The morphology of the prepared composite gel beads exhibited a spherical shape surface covered by silica particles. The unfunctionalized and functionalized beads were studied for the adsorption of methylene blue (MB) and Acid blue 25 (AB25) from water. The influence of pH, time, dye concentration, and temperature on the adsorption characteristics was investigated. The results showed that the highest adsorption amount of dyes was reached using the functionalized chitosan beads under the following conditions; pH = 5 for AB25 and pH = 6 for MB, time = 120 min, and T = 20 °C. The adsorbed yield of MB using the composite beads increased three times more than the capacity of chitosan beads and it was improved 1.4 times in the case of AB25. The mean free energy values (74.53-223.61 kJ mol-1), computed from the Dubinin-Radushkevich model suggested the chemi-sorption nature of the adsorption phenomenon.


Assuntos
Quitosana/química , Quitosana/síntese química , Corantes/química , Dióxido de Silício/química , Poluentes Químicos da Água/química , Adsorção , Técnicas de Química Sintética , Corantes/isolamento & purificação , Microesferas , Poluentes Químicos da Água/isolamento & purificação
20.
Int J Biol Macromol ; 145: 1106-1114, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31730958

RESUMO

The repulsion between cellulose and anionic entities could be overcome by imparting cationic sites on its structure. In this work, we studied the treatment of cotton fabric with different amounts of chitosan bio-polymer (0.0125-0.075%), dimethyl diallyl ammonium chloride and diallylamin co-polymer (1-5%), alum (0.5-20 g/L), and sodium chloride (2-40 g/L) in order to improve their dyeing behaviors with an ecological extract of Pistacia vera hulls by-products. The chemical modification of the cellulosic fibers was confirmed using Fourier Transform Infra-Red (FT-IR) and Scanning Electron Microscopy (SEM). The unmodified and modified cellulosic samples were, then, dyed with Pistacia vera extract. The dyeing characteristics were assessed through the measurements of the color coordinates and the color strength. Results showed that the dyeing performance followed the order: Cotton-dimethyl diallyl ammonium chloride and diallylamin co-polymer (K/S = 9.6) > Cotton-Chitosan (K/S = 8.97) > Cotton-Alum (8.84) > Cotton-NaCl (K/S = 6.06) > Untreated cotton (K/S = 1.98). All dyed samples exhibited good fastness to washing, rubbing and light. Overall, it has shown in this study that the functionalization of cellulose structure could greatly improve its dyeing behavior depending on the cationic sites number.


Assuntos
Corantes/química , Fibra de Algodão , Pistacia/química , Extratos Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Ânions , Cátions/química , Celulose/química , Cor , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Polímeros , Têxteis
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