Hemicelluloses hydrogel: Synthesis, characterization, and application in dye removal.

Novel materials using biowaste as adsorbents in wastewater treatment have been allocated considerable interest. Herein, we present the synthesis of different hydrogels of crosslinked polyacrylamide in presence of hemicelluloses with/ without bentonite, using a soft reaction condition. The structure of new hydrogels was characterized by spectroscopic, thermal and microscopic experiments. The semi-interpenetrated network with hemicelluloses: 10 %; acrylamide 79 %; bentonite 10 %; N,N,N',N'-tetramethylethylenediamine: 1 % allows reducing 20 % the use of non-renewable acrylamide, without changing its decomposition temperatures and keeping its water absorption capacity. This hydrogel was applied to dye removals, such as rhodamine B, methylene red and methylene blue in aqueous solutions. In the case of methylene blue, highest removal is observed with maximum adsorption of qmax = 140.66 mg/g, compared to material without hemicelluloses that only a qmax = 88.495 mg/g. The adsorption kinetics and equilibrium adsorption isotherms are in accordance with the pseudo-second-order kinetic model and Langmuir isotherm model, respectively. The developed hydrogel from hemicelluloses represents a potential alternative adsorbent for a sustainable system of sewage treatment.

Alternative modification by grafting in bamboo cellulose nanofibrils: A potential option to improve compatibility and tunable surface energy in bionanocomposites.

Chemical modification in surface of cellulose nanofibrils CNFs (20 nm) from an endemic and non-significant value-added, Argentine bamboo, was developed. The modification in the CNFs was carried out with three simple routes using a low molecular weight polylactic acid synthesized in our laboratory (PLA1). The first step comprises of protection of the hydroxyl groups of PLA1 through a benzoylation (PLA1Bz). The next step consisted of the activation of carboxyl groups using thionyl chloride and the last reaction was the grafting of the modified PLA onto the CNFs (PLA1Bz-g-CNF). The covalently functionalization is confirmed by spectroscopically techniques as well as PLA1Bz-g-CNFs were characterized by thermal analyses. The PLA1Bz-g-CNFs were taken up such as nanocharges to improve properties of compatibilization and changing surface properties in films based on PLA. The comparison between the films with PLA1Bz-g-CNFs with respect to the physic mixture of the components (PLA1Bz/CNF), shows an improvement in the thermal, mechanical, and surface properties of the material, particularly when 5% of PLA1Bz-g-CNFs was added. The dispersive (γS D) component of film is increased in 36.1 mN/m respect to 29.3 mN/m from the films obtained with the physic mixture nanofibrils without modification and a plasticizing effect was noticed in the final material.