Abstract The content of free and bound phenolics and their antioxidant capacity in cookies enriched by nettle seed flour and a nettle seed phenolic extract, before, during and after thermal processing (baking at 180°C for 25 min) were examined. The results compare these properties to a cookie obtained only from wheat flour, as the control. Better results were obtained by incorporating nettle seed flour than nettle seed extract. During thermal processing, different changes of phenolic content and antioxidant capacity (increase, decrease or retention) occurred, depending on the form of the phenolics (free or bound), thermal processing time, the cookie and applied antioxidant assays. The free and bound phenolics in the cookie with seed flour were more stable than in the other cookies. At the end of the thermal processing, the cookie with nettle seed flour had a higher content of free and bound phenolics (2.1 and 2.5 times, respectively), and greater antioxidant capacity (the DPPH RSC of free and bound phenolics 9.2 and 4.6 times, and of reducing power 1.6 and 3.4 times, respectively) than the control. There are great possibilities of using nettle seeds in the food industry with the aim of obtaining a functional product with powerful health benefits.

The photodecolourisation of textile dye Reactive Blue 19 (RB 19), an anionic anthraquinone dye of the reactive class, was investigated using UV radiation in the presence of H2O2 in a batch photo-reactor with low-pressure mercury lamps. The effects of the system parameters: initial pH, initial dye concentration, concentration of peroxide and radiation intensity, as well as the presence of salts, (NaCl, Na2SO4, NaNO3, NaH2PO4) on dye decolourisation was examined. Increasing the initial pH resulted in an increase in decolourisation efficiency. Results showed that with an increase of dye concentration from 10 to 100 mg∙ℓ-1, the efficiency of the process decreases. The highest decolourisation rates were noted at H2O2 concentrations of approximately 30 mmol∙ℓ-1. The increase of radiation intensity from 730 to 1 950 µW∙cm-2, linearly increases decolourisation efficiency. The inorganic ions investigated have inhibiting effects on RB 19 decolourisation by the UV/H2O2 process with inhibition intensities in the following order: H2PO4- > NO3- > SO4(2-) > Cl-. This study has shown that the UV/H2O2 process is a promising technology for degradation of RB 19 in water and wastewater.

The removal of copper(II) ion from aqueous solution by the granular activated carbon, obtained from hazelnut shells (ACHS) (Corylus avellana L. var. lunga istriana), was investigated. The ACHS was prepared from ground dried hazelnut shells by specific method carbonisation and water steam activation at 950ºC for 2 h. The granular activated carbon produced from hazelnut shells has a high specific surface area (1 452 m²·g-1) and highly developed microporous structure (micropore volume: 0.615 cm³·g-1). In batch tests, the influences of solution pH, contact time, initial metal ion concentration and temperature on the sorption of copper(II) ion on ACHS were studied. The results indicate that sorption of copper(II) ion on ACHS strongly depends on pH values. The adsorption data can be well described by the Langmuir isotherm and Redlich-Peterson model. The monolayer adsorption capacity of the ACHS-copper(II) ion, calculated from the Langmuir isotherms, is 3.07 mmol·g-1. The time-dependent adsorption of copper(II) ion could be described by the pseudo second-order and Elovich kinetics, indicating that the rate-limiting step might be a chemical reaction. The intra-particle diffusion model indicates that adsorption of copper(II) ions on ACHS was diffusion controlled.