The removal of arsenate ions from aqueous solutions at near-neutral pH was carried out using chitosan-magnetite (ChM) hydrogel beads in batch systems. Equilibrium isotherms and kinetic studies are reported. Obtained equilibrium and kinetic data were fitted to mathematical models, estimating model parameters by non-linear regression analysis. Langmuir model was found to best fit equilibrium data; a maximum adsorption capacity of 66.9 mg As/g was estimated at pH 7.0. Pseudo-first order kinetic model was observed to best fit kinetic data. The pH of the solution was observed to increase with increasing contact time, which is attributed to protonation of amine groups present in the hydrogel. Protonation of functional groups in the ChM sorbent yields a higher number of active sites for arsenate removal, being as this a process that can’t be overlooked in future applications of ChM hydrogel for the removal or arsenate ions. Chitosan-magnetite and ChM-arsenate interactions were determined by XPS. Arsenate removal using fixed-bed column packed with ChM was carried out, reporting a non-ideal behavior attributed to pH increase of the effluent caused by proton transfer to ChM hydrogels.
In this work, a photo-polymerization route was used to obtain potassium acrylate-co-acrylamide hydrogels with enhanced mechanical properties, well-defined microstructures in the dry state, and unique meso- and macrostructures in the hydrated state. The properties of the hydrogels depended on the concentration of the crosslinking agent. Mechanical properties, swelling capacity, and morphology were analyzed, showing a well-defined transition at a critical concentration of the crosslinker. In terms of morphology, shape-evolving surface patterns appeared at different scales during swelling. These surface structures had a noticeable influence on the mechanical properties. Hydrogels with structures exhibited better mechanical properties compared to unstructured hydrogels. The critical crosslinking concentration reported in this work (using glycerol diacrylate) is a reference point for the future preparation of multistructured acrylic hydrogel with enhanced properties.
Radiation chemistry presents a unique avenue for developing innovative polymeric materials with desirable properties, eliminating the need for chemical initiators, which can be potentially detrimental, especially in sensitive sectors like medicine. In this investigation, we employed a radiation-induced graft polymerization process with N-vinylcaprolactam (NVCL) to modify lignocellulosic membranes derived from Agave salmiana, commonly known as maguey. The membranes underwent thorough characterization employing diverse techniques, including contact angle measurement, degree of swelling, scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR), nuclear magnetic resonance (CP-MAS 13C-NMR), X-ray photoelectron spectroscopy (XPS), and uniaxial tensile mechanical tests. The membranes’ ability to load and release an antimicrobial glycopeptide drug was assessed, revealing significant enhancements in both drug loading and sustained release. The grafting of PNVCL contributed to prolonged sustained release by decreasing the drug release rate at temperatures above the LCST. The release profiles were analyzed using the Higuchi, Peppas–Sahlin, and Korsmeyer–Peppas models, suggesting a Fickian transport mechanism as indicated by the Korsmeyer–Peppas model.
This work presents a review related to the obtainment of cellulose from different structures in agro-industrial residues, both for application in the food industry and for the reinforcement of other materials. Cellulose nanofibers are produced by the heart of palm (Bactris gasipaes) industry in Brazil and are used as a stabilizer in avocado oil emulsions; conversely, cellulose nanocrystals are produced in waste from the tequila industry (Agave tequilana Weber var. Azul) in Jalisco, Mexico, and are used for reinforcement applications.
Es importante reflexionar sobre la producción de grandes volúmenes de biomasa que se generan en la producción del tequila, los cuales tienen como destino final el suelo y los cuerpos de agua, considerados como elementos básicos de todo ecosistema; catalogando a la industria tequilera como una de las industrias más contaminantes en el occidente de México. Según datos del Consejo Regulador de Tequila (CRT)6 en el 2021 se usaron casi un millón de toneladas de agave y se generaron aproximadamente 9418 toneladas de bagazo de agave.