Particleboard Production from Paulownia tomentosa (Thunb.) Steud. Grown in Portugal.

Paulownia wood has raised high attention due to its rapid growth and fire resistance. The number of plantations in Portugal has been growing, and new exploitation methods are needed. This study intends to determine the properties of particleboards made with very young Paulownia trees from Portuguese plantations. Single layer particleboards were produced with 3-year-old Paulownia trees using different processing parameters and different board composition in order to determine the best properties for use in dry environments. The standard particleboard was produced at 180 °C and a 36.3 kg/cm2 pressure for 6 min using 40 g of raw material with 10% urea-formaldehyde resin. Higher particle size lead to lower-density particleboards, while higher resin contents lead to higher density of the boards. Density has a major effect on board properties with higher densities improving mechanical properties such as bending strength, modulus of elasticity (MOE) and internal bond, lower water absorption but higher thickness swelling and thermal conductivity. Particleboards meeting the requirements for dry environment according to NP EN 312 standard, could be produced with young Paulownia wood with acceptable mechanical and thermal conductivity properties with density around 0.65 g/cm3 and a thermal conductivity of 0.115 W/mK.

Study of two cork species as natural biosorbents for five selected pesticides in water.

The present study evaluates biosorption efficiencies of pesticides atrazine, fluazifop-P-butyl, lactofen, lambda-cyhalothrin and chloropyrifos on corks of Quercus cerris and Quercus suber trees. The studies were carried out in batch and effects of pH (3, 7 and 9), temperature (10, 20, 30 and 40 °C), and time on adsorption were measured. Pesticide analyzes were performed with an Ion-trap Mass Spectrometer following the SANCO/10232/2006 EU extraction protocol for pesticides. The results show that the highest adsorption efficiency (80% and 70%) of the pesticides was found at pH 3, 30 °C and 360 minutes. The adsorption kinetics of pesticides followed pseudo-second order and pseudo-first order kinetics. The results obtained in this study show that Q. cerris and Q. suber corks can be used to develop efficient and economical cork-based alternatives for the treatment of environments contaminated with pesticides.