Rapid interaction, in aqueous media, between anionic dyes and cellulosic Nerium oleander fibers modified with Ethylene-Diamine and Hydrazine

Chemical modification of microcrystalline cellulose with polyethyleneimine and hydrazine: Characterization and evaluation of its adsorption power toward anionic dyes

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.

Characterization and application of ligno-cellulosic fibers derived from Robinia Pseudoacacia for the bio-sorption of methylene blue from water

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.

Aminolysis as a surface functionalization method of aliphatic polyester nonwovens: impact on material properties and biological response

Aminolysis treatment improves L929 cell–scaffold interaction. It is possible to reach compromise between the concentration of NH2 groups and mechanical properties change.

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

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.

2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties

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.

Characterization and valuable use of Calotropis gigantea seedpods as a biosorbent of methylene blue

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.

Design and Evaluation of a New Natural Multi-Layered Biopolymeric Adsorbent System-Based Chitosan/Cellulosic Nonwoven Material for the Biosorption of Industrial Textile Effluents

The adsorption phenomenon using low-cost adsorbents that are abundant in nature is of great interest when the adsorbed capacity is significant. A newly designed natural polyelectrolyte multi-layered (PEM) biopolymeric system-based chitosan/modified chitosan polymer and functionalized cellulosic nonwoven material was prepared and used as an effective adsorbent for Reactive Red 198 (RR198) dye solutions. The bio-sorbent was characterized by FTIR, SEM, and thermal (TGA/DTA) analysis. The swelling behavior was also evaluated, showing the great increase of the hydrophilicity of the prepared adsorbent biopolymer. The effect of various process parameters on the performance of RR198 dye removal such as pH, contact time, temperature, and initial dye concentration was studied. The biopolymeric system has shown good efficiency of adsorption compared to other adsorbents based on chitosan polymer. The highest adsorption capacity was found to be 722.3 mgg⁻¹ at pH = 4 (ambient temperature, time = 120 min and dye concentration = 600 mg L⁻¹). The adsorption process fitted well to both pseudo-second-order kinetics and Freundlich/Temkin adsorption isotherm models. Regarding its low cost, easy preparation, and promising efficient adsorption results, this new concepted multi-layered bio-sorbent could be an effective solution for the treatment of industrial wastewater.

A Cellulosic Fruit Derived from Nerium oleander Biomaterial: Chemical Characterization and Its Valuable Use in the Biosorption of Methylene Blue in a Batch Mode

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 pH_pzc 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.

Populus tremula, Nerium oleander and Pergularia tomentosa seed fibers as sources of cellulose and lignin for the bio-sorption of methylene blue

Cellulose-based substrates could represent potential funds for the sorption of pollutants. Herein, methylene blue was selected for demonstrating the bio-sorption efficiency of Nerium oleander, Pergularia tomentosa and Populus tremula seed fibers. Their cellulose contents were 45%, 43.8% and 60%. Their lignin amounts were 21%, 8.6% and 12%, respectively. Fourier Transform InfraRed suggested that the interaction of these bio-products with methylene blue could occur between hydroxyl and ester groups of cellulose and lignin and the sulfur and nitrogen atoms of the dye. Scanning Electron Microscopy showed a swelling of the bio-matters after dye biosorption. From X-Ray Diffraction, the shifting for higher values of the peaks related to the amorphous phase indicated the establishment of new rearranged regions. Such change from the decomposition behavior event studied by Thermogravimetric Analysis/Differential Thermal Analysis revealed that methylene blue was interacted with cellulose and lignin structures. The effect of adsorbent dosage, pH, time, dye concentration and temperature was investigated in controlled batch experiments. Excellent sorption capacities followed the order: Nerium oleander (280.2 mg g^-1) > Populus tremula (168 mg g^-1) > Pergularia tomentosa (145.3 mg g^-1). Freundlich fitted best the equilibrium data suggesting cooperative interactions via physisorption and chemisorption phenomenon. Kinetic data complied well with the pseudo-second-order suggesting a chemisorption mechanism.