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.

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.

Preparation of alkali lignin extracted from ligno-cellulosic populus tremula fibers: Application to copper oxide nanoparticles synthesis, characterization, and methylene blue biosorption study.

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.

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.

An insight into methylene blue adsorption characteristics onto functionalized alginate bio-polymer gel beads with λ-carrageenan-calcium phosphate, carboxymethyl cellulose, and celite 545.

Herein, λ-carrageenan-calcium phosphate (λ-Carr-Cp), carboxymethylcellulose (CMC) and celite 545 (Ce545) were used to functionalize sodium alginate bio-polymer (SAB). The water content in the wet beads was about 98%. Fourier Transform Infra-Red (FT-IR) showed that SAB@λ-Carr-Cp, SAB@CMC, and SAB@Ce545 could interact through intermolecular hydrogen and electrostatic interactions. Scanning Electron Microscopy (SEM) revealed that the morphology of the functionalized beads had a porous sheet structure. Energy Dispersive X-Ray (EDX) depicted that the peak intensity of the carbon element became more intense in the case of organic modification. The appearance of mineral elements characteristics of Ce545 (Si, Al) and Cp (P) proved the incorporation of these inorganic reagents into the alginate matrix. The data from batch adsorption experiments indicated that the adsorption of methylene blue (MB) depended on pH, time, temperature, and dye concentration. At equilibrium, the adsorption capacities followed the order: SAB@Ce545 (7.5 mg g-1 wet) > SAB@λ-carr-Cp (6.8 mg g-1 wet) > SAB@CMC (6.5 mg g-1 wet) > SAB (5.77 mg g-1 wet). Kinetic data agreed with pseudo second-order suggesting chemi-sorption mechanism. The equilibrium data fitted for Freundlich. In summary, this provided assembly strategy could offer a new research opportunity for developing functionalized biopolymers with new functions and potential applications.

FT-IR spectroscopy and morphological study of functionalized cellulosic fibers: Evaluation of their dyeing properties using biological Pistacia vera hulls by-product extract.

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.

[λ­Carrageenan­calcium phosphate] and [sodium alginate­calcium phosphate] modified with dimethyl diallyl ammonium chloride and diallylamin co-polymer as efficient adsorbents of anionic dyes.

Alginate and carrageenan bio-polymers have been proved to be, only, good sorbents of cationic dyes. In this study, we reported the synthesis of [λ­carrageenan­calcium phosphate] and [sodium alginate­calcium phosphate] modified with dimethyl diallyl ammonium chloride and diallylamin co-polymer, which could be used as effective adsorbents of anionic dyes. Evidence of chemical modification was proved through Fourier Transform Infrared Spectroscopy (FT-IR) band shifting, peaks broadening in X-Ray Diffraction (XRD) and the change in thermal event (TGA). The sorption process was studied using acid blue 25 as representative anionic dye. The adsorbed quantity reached, at equilibrium, 446 mg/g and 195 mg/g using cationized [sodium alginate­calcium phosphate] and cationized [λ­carrageenan­calcium phosphate], respectively. However, it does not exceed 3.4 mg/g in the case of the unmodified [sodium alginate­calcium phosphate]. The sorption of acid blue 25 using cationized hybrid materials complied well with the pseudo-second-order suggesting a chemi-sorption. Freundlich isotherm described well the adsorption mechanism of the three studied adsorbents. In summary, the high sorption capacities of the cationized hybrid materials obtained in this study suggest their use as effective adsorbents of acid dyes from wastewaters.

Production of cellulose from Aegagropila Linnaei macro-algae: Chemical modification, characterization and application for the bio-sorptionof cationic and anionic dyes from water.

Marine algae wereprovedto begoodadsorbentsformany pollutants. In this work, Aegagropila Linnaei (Aegagropila L.) was treated with sodium hydroxideand sodium chlorite. The extracted cellulose content was 18.5%. It was functionalized with Dimethyl diallyl ammonium chloride and diallylamin co-polymer. The products were characterized using Fourier Transform Infra-Red (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and thermogravimetric analyses (TGA). The samples were studied as adsorbents of methylene blue(MB) and acid blue 25(AB25) in a controlled batch system. The effect of salts concentration (KCl, NaCl, and CaCl2), adsorbent dosage, pH, contact time and initial dye concentration on the adsorption mechanism was discussed. At equilibrium, the adsorption of MB and AB25ontoextracted and functionalized cellulose reached 109 mg/g and 139 mg/g, respectively. Under the same conditions, the adsorption capacity of AB25 and MB onto unmodified Aegagropila L. was, only, 32 mg/g and 47 mg/g. The pseudo second-order kinetic equation exhibited the optimal fitting results. The mean free energy (E = 70.71 to 223.6 Kj/mol), calculated from Dubinin-Radushkevich isotherm, suggested a chemi-sorption mechanism. Overall, the results confirmed that the studied products could be considered as valuable bio-sorbents of dyes from contaminated waters.

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.