For the first time, sulfanilamide (SFD) was determined in otologic solution, human urine and serum by electroanalytical techniques on glassy carbon electrode (GCE). The cyclic voltammetry (CV) experiments showed an irreversible oxidation peak at +1.06 V in 0.1 mol/L BRBS (pH = 2.0) at 50 mV/s. Different voltammetric scan rates (from 10 to 250 mV/s) suggested that the oxidation of SFD on the GCE was a diffusion-controlled process. Square-wave voltammetry (SWV) method under optimized conditions showed a linear response to SFD from 5.0 to 74.7 μmol/L (R = 0.999) with detection and quantification limits of 0.92 and 3.10 μmol/L, respectively. The developed SWV method showed better results for detection limit and linear range than the chronoamperometry method. It has been successfully applied to determine SFD concentration in pharmaceutical formulation, human urine and serum samples with recovery close to 100%.

In a recent paper, novel polyester nanocomposites reinforced with up to 3 wt% of cellulose nanocrystals (CNCs) extracted from conifer fiber were characterized for their crystallinity index, water absorption, and flexural and thermal resistance. The use of this novel class of nanocomposites as a possible substitute for conventional glass fiber composites (fiberglass) was then suggested, especially for the 1 and 2 wt% CNC composites due to promising bending, density, and water absorption results. However, for effective engineering applications requiring impact and tensile performance, the corresponding properties need to be evaluated. Therefore, this extension of the previous work presents additional results on Izod and tensile tests of 1 and 2 wt% CNC-reinforced polyester composites, together with a comparative cost analysis with fiberglass. The chemical effect caused by incorporation of CNCs into polyester was also investigated by FTIR. In comparison to the neat polyester, the Izod impact energy increased 50% and 16% for the 1 and 2 wt% composites, respectively. On the other hand, the tensile strength and Young’s modulus remained constant within the ANOVA statistical analysis. FTIR analysis failed to reveal any chemical modification caused by up to 2 wt% CNC incorporation. The present impact and tensile results corroborate the promising substitution of a polyester composite reinforced with very low amount of CNCs for common fiberglass in engineering application.

The textile industry is known for its high water consumption and production of toxic effluents, including azo dyes such as Reactive Black 5 (RB-5), which are resistant to removal. Adsorption offers a promising, cost-effective solution, particularly with value-added composites made from abundant materials. This study synthesized, characterized, and applied a C/TiO₂-based composite to remove RB-5 from water. XRD analysis only confirmed anatase as the primary support, while FTIR detected adsorbate molecules on the C/TiO₂ surface, marked by the appearance of a sulfone group band. Raman and XPS analyses indicated reduced Sp² carbon content and lower graphitization after adsorption, probably due to mechanical stress. Additionally, nitrogen physisorption analysis demonstrated that the material is mesoporous, with a surface area of 56.24 m² g^-1, and a pore diameter of 9.41 nm. The composite exhibited strong affinity for anionic species like RB-5, especially at pH values below the point of zero charge (7.47). Batch studies demonstrated Avrami kinetic adsorption at a rate of 0.3023 min^-1 (at 25 °C), while temperature effects followed the Arrhenius model, with an activation energy of +41.10 kJ mol^-1. Sips isotherm data indicated a maximum adsorption capacity of 17.48 mg g^-1 at 55 °C. Thermodynamic analysis confirmed an entropically controlled, endothermic, spontaneous process at high temperatures. These aspects confirm the potential of eco-friendly C/TiO₂ composite for effective RB-5 removal from aqueous solutions.