This paper highlights the efficiency of ultrasonication, as a clean and energy-saving method for the preparation of cellulose–iron oxide ferromagnetic composites in two steps. Hydroxyl-functionalized maghemite–goethite nanoparticles (MG) having a saturation magnetization of 56.9 emu g⁻¹ at room temperature were first synthesized by a one-pot procedure involving ultrasonication of an aqueous alkaline Fe²⁺ salt solution. Organic–inorganic nanocomposites were obtained by a second ultrasonication step of an aqueous suspension of micronized cellulose and MG nanoparticles. The cumulative effect of ultrasonication and MG nano-projectiles was found to strongly decrease the degree of crystallinity of cellulose. The microstructural characterisation of the resulting composite evidenced its size polydispersity, with small nanoparticles uniformly attached on the surface of cellulose microfibrils. Vibrating sample magnetic measurement indicated a hysteresis curve specific to ferromagnetic materials and the appearance of a superparamagnetic phenomenon at low temperature (a blocking temperature of 62 K). Cellulose/iron oxide clusters with an average size around 7 nm and characterized by high decomposition temperatures (around 645 °C) were proven to be responsible for the observed superparamagnetic phenomenon. The superiority of the ultrasonication process versus a procedure involving simple mechanical stirring, in terms of composite yield, dispersion uniformity of MG nanoparticles and magnetic properties is discussed.

This study reports the valorization of pistachio shell agricultural waste, aiming to develop an eco-friendly and cost-effective biosorbent for cationic brilliant green (BG) dye adsorption from aqueous media. Pistachio shells were mercerized in an alkaline environment, resulting in the treated adsorbent (PS_NaOH). The morphological and structural features of the adsorbent were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy, and polarized light microscopy. The pseudo-first-order (PFO) kinetic model best described the adsorption kinetics of the BG cationic dye onto PS_NaOH biosorbents. In turn, the equilibrium data were best fitted to the Sips isotherm model. The maximum adsorption capacity decreased with temperature (from 52.42 mg/g at 300 K to 46.42 mg/g at 330 K). The isotherm parameters indicated improved affinity between the biosorbent surface and BG molecules at lower temperatures (300 K). The thermodynamic parameters estimated on the basis of the two approaches indicated a spontaneous (ΔG < 0) and exothermic (ΔH < 0) adsorption process. The design of experiments (DoE) and the response surface methodology (RSM) were employed to establish optimal conditions (sorbent dose (SD) = 4.0 g/L and initial concentration (C₀) = 10.1 mg/L), yielding removal efficiency of 98.78%. Molecular docking simulations were performed to disclose the intermolecular interactions between the BG dye and lignocellulose-based adsorbent.

Herein, we report the performance of some low-cost biosorbents developed by environment-friendly modification of walnut shells. Two types of biosorbents were prepared by ecological modification of walnut shell surfaces: (1) biosorbents obtained by hot water treatment (WS_H2O) and (2) biosorbents produced by mercerization (WS_NaOH). Different techniques were used to evaluate the morphological, elemental, and structural modification of the biosorbents, by comparison with raw materials. These characterization techniques involved scanning electron microscopy (SEM) coupled with energy-dispersive X-ray analysis, and Fourier-transform infrared spectroscopy (FTIR). The biosorbents were employed for the removal of methylene blue (MB) and crystal violet (CV) cationic dyes (as model organic pollutants) from aqueous solutions. The kinetic adsorption data mainly followed the pseudo-first-order model. The maximum adsorption capacities of the produced biosorbents ranged from 102 to 110 mg/g and were observed at 330 K. Equilibrium data for adsorption were fitted to Langmuir and Freundlich isotherm models. The calculated values of thermodynamic parameters suggested that the investigated adsorption processes were exergonic (ΔG < 0) and exothermic (ΔH < 0). In addition, a possible valorization of the cost-effective and eco-friendly spent biosorbents was tested by performing secondary adsorption of the anionic dyes.

Chitosan-sulfated titania composite membranes were prepared, characterized, and evaluated for potential application as polymer electrolyte membranes. To improve the chemical stability, the membranes were cross-linked using sulfuric acid, pentasodium triphosphate, and epoxy-terminated polydimethylsiloxane. Differences in membranes’ structure, thickness, morphology, mechanical, and thermal properties prior and after cross-linking reactions were evaluated. Membranes’ water uptake capacities and their chemical stability in Fenton reagent were also studied. As proved by dielectric spectroscopy, the conductivity strongly depends on cross-linker nature and on hydration state of membranes. The most encouraging results were obtained for the chitosan-sulfated titania membrane cross-linked with sulfuric acid. This hydrated membrane attained values of proton conductivity of 1.1 × 10⁻³ S/cm and 6.2 × 10⁻³ S/cm, as determined at 60 °C by dielectric spectroscopy and the four-probes method, respectively.

The paper focuses on the advances in the field of pain treatment by transdermal delivery of specific drugs. Starting from a short description of the skin barrier, the pharmacodynamics and pharmacokinetics including absorption, distribution, action mechanism, metabolism and toxicity, aspects related to the use of pain therapy drugs are further discussed. Most recent results on topical anesthetic agents as well as the methods proved to overcome the skin barrier and to provide efficient delivery of the drug are also discussed. The present review is proposing to summarize the recent literature on the pharmacotherapeutic principles of local anesthetics and non-steroidal anti-inflammatory drugs, generally used to alleviate pain but also the drugs as nanoformulations with potential applications in transdermal delivery. A special attention is given to efficient formulations meant for transdermal penetration enhancement of anesthetics where the drug is encapsulated into macrocyclic molecules (cyclodextrins, cyclodextrin derivatives), liposomes or polymer nanoparticles and hydrogels.

Recently, the ultrasound-assisted sol-gel synthesis procedure of mesoporous titania (TiO₂) photocatalysts caught the researcher’s attention, due to the physicochemical properties enhancement of the resulting titania nanomaterials. Thus, by varying different synthesis parameters particular characteristics could be obtained. In the present study, the ultrasound pulse on/off ratio has been considered and the effect of the envisaged parameter on the textural, morphological, and optical features of titania nanomaterial has been investigated. Therefore, X-ray Diffraction (XRD), Fourier-Transform Infrared spectroscopy (FTIR), N₂-sorption measurements, SEM imaging, and UV-Vis Diffuse Reflectance spectroscopy (UVDR) have been used. And further, the photocatalytic activity of the prepared TiO₂ materials was evaluated by the features developed about the applied ultrasound pulse on/off ratio as 1/1, 2/1, 3/1, 4/1, 1/3 and 2/2. It was found that the ultrasound pulse on/off ratio considered in the synthesis procedure of titania leads to TiO₂ materials with different textural (S_BET = 98–156 m²/g), morphological, and optical (E_g = 3.1–3.2 eV) characteristics. For this reason, TiO₂ nanomaterials prepared were found to exhibit suitable features for photocatalytic applications. Thus, the TiO₂ 4.1 sample prepared at 4/1 ultrasound pulse on/off ratio revealed the highest photodegradation efficiency of Congo Red dye (98.28%) as the results of photocatalytic tests show. More than that, a possible reaction mechanism of the CR photodegradation process through the contribution of reactive oxygen species (·HO, ·O₂⁻), holes (h⁺), and electrons (e⁻) of developed titania photocatalyst was proposed.