This work focuses on the characterization of five palygorskite clays from the Brazilian state of Piaui and their feasibility as eco-friendly adsorbents for the removal of Fe³⁺ ions from aqueous solutions. For characterization, we applied the techniques of X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), size distribution measurements, density measurement by He pycnometry, superconducting quantum interference device (SQUID) magnetometry, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTA), zeta potential measurement, hydrophobicity determination by contact angle, Brunauer–Emmett–Teller surface area analysis (BET technique) and atomic force microscopy (AFM). Batch experiments were performed in function of process parameters such as contact time and initial concentration of Fe³⁺. The natural palygorskites (Palys) had excellent performance for the removal of Fe³⁺ from aqueous solutions by adsorption (around 60 mg/g), and the Langmuir is supposedly the best model fitted the experimental data.

PVA cryogels are well established as candidate biomaterials for wound healing applications but are not themselves biodegradable or antimicrobial. Blending PVA with NaCMC (CMC) or gelatin (G) can increase the gel’s ability to swell and would introduce a degree of biodegradability. The incorporation of appropriate amounts of a natural antimicrobial/healing agents, such as honey (H), would contribute to the gels properties. The present work addresses the development and characterization of layered gels (PVA-H, PVA-CMC-H and PVA-G-H, with empty PVA, PVA-CMC, PVA-G gels presented as controls). The gels were characterized by FTIR, DSC, in vitro analysis of swelling and microbiological (S. aureus) effects. Addition of gelatin, NaCMC and honey to PVA diminished the PVA chains’ ability to pack into crystallites. Samples containing honey swelled less and presented higher weight loss/biodegradability than samples without honey. Only the honey-laden PVA-CMC and PVA-G presented activity against S. aureus.

Acute wound dressings can be based on PVA hydrogels, which present many characteristics of an ideal dressing, e.g., fluid uptake, a moisturized environment, etc. The lack of antimicrobial properties leads to the addition of natural active agents. The present work aims to manufacture and compare PVA gels loaded with Barbatimão bark extract, Leucaena bark extract, Aloe vera, and Lavender essential oil. They were characterized by FTIR, swelling tests, SEM, actives release. There were interactions between PVA and the active agents. The addition of Leucaena and Barbatimão increased the PVA ability to swell, but the opposite was found for Aloe vera and Lavender essential oil. PVA-Lavender essential oil samples presented interconnected pores, while samples with essential oil or extracts presented high crystallinity. Lavender essential oil and Aloe vera presented the highest release. The Barbatimão and Leucaena samples’ release may be related to the samples’ swelling, but the initial release of Aloe vera and Lavender samples was diffusion controlled by swelling. Their long-term release was dose-dependent for Aloe vera, while it was a non-Fickian diffusion for Lavender essential oil related to the hydrogel’s relaxation step. There is a synergistic effect when Aloe vera and Lavender essential oil are loaded in PVA hydrogels.