The present study describes a method for the determination of As (III) and As (V) in copper electrolytes. The method is based on the separation of As (III) from a copper electrolyte by triple liquid-liquid extraction using a non-polar organic solvent in a medium of 10-12 mol L–1 HCl. The extract contains As (III) and the raffinate-As (V), respectively. As(III) specie can be re-extracted from the organic solvent through the water. Analyzes of the concentration of As in the re-extract and raffinate were performed by ICP-OES spectroscopic method. The average recovery of arsenic by the proposed method is about 99%. Repeatability was estimated with RSD (n = 6). Selectivity and accuracy were proven by the standard addition method. The relative error for restoring the standard addition of As (III) is about 0.3%. The speciation method analysis could be applied for determination of the arsenic species in the analytical quality control of refined copper in copper tanks in the production of copper cathodes.

Waste lignin from the hydrolysis of lignocellulosic materials is an abundant but underused by-product of the pulp and biorefinery industries. Phenolic compounds derived from lignin, rich in aromatic structures, show strong antioxidant potential and can be applied in polymer stabilization, food, and medical fields. This study evaluated the radical-scavenging activity of phenolic fractions obtained from alkaline-treated waste lignin against DPPH● and ABTS•⁺, using Trolox as a reference. Both spectrophotometric and electrochemical techniques were employed, providing deeper insight into the underlying mechanisms. Depending on the assay, the phenolic extracts demonstrated substantial radical-scavenging capacity, in some cases matching or surpassing that of Trolox. This behavior was linked to electron/proton transfer pathways, radical reactivity, and solubility effects. The combined use of multiple antioxidant tests offered a comprehensive characterization of the bioactivity of lignin-derived phenolics and supports their potential as sustainable sources of antioxidant compounds within a circular economy framework. Furthermore, the study examined how toluene-extracted phenolics affect the thermo-oxidative stability of model polyurethane films. Incorporating small amounts (1%, 3%, 5%) into the polymer matrix showed that a 1% loading provides the most effective stabilization. At higher concentrations, however, additional oxidative processes seem to be activated, as indicated by FTIR measurements and thermogravimetric analysis.

Soil collected from random areas of non-ferrous mines and smelters was studied in order to develop a low-cost but effective method for quantifying arsenic (III), arsenic (V), and total arsenic in contaminated soil. Hydrochloric acid microwave extractions have been used as a method to digest arsenic from soil in a form of solution suitable for speciation. Arsenic (III) is selectively extracted into benzene as arsenic trichloride from a highly concentrated hydrochloric acid solution. This was followed by the arsenic being extracted back into water. The total inorganic content of arsenic (V) can be directly determined by anodic oxidation of a gold screen-printed electrode using electrochemical detection. The amount of available Arsenic (III) in the sample is determined by pre-oxidation with KMnO4 directly added to the electrochemical cell or by directly increasing the pH of the medium. ICP-MS was used to confirm all analyses for the various arsenic species as well as the discovery of total arsenic in the soil. It was discovered that the electrochemical method used allows for the cheap, quick, and selective determination of micro amounts of arsenic forms in contaminated soils.