Effect of the passive chemical modification of wood with silicon dioxide (silica) on its properties and inhibition of moulds

This work investigates how wood modification with silicon dioxide affects its selected physical and mechanical properties and resistance to moulds. Silicon mineralization can improve some of the technical properties of wood and extend the service-life of wooden structures. Silicon, which is contained in inorganic and organic-inorganic substances that are used for artificial wood mineralization or is the main component at natural wood mineralization, was used in the form of colloidal silicon dioxide and its various concentrations for pressure impregnation of beech (Fagus sylvatica) and Silver fir (Abies alba) wood samples. Following, physical, mechanical and biological properties of such modified woodswere tested together with waterlogged fir wood stored in water over a long period. Silicon-dioxide did not significantly improve properties of beech and fir woods, probably due to the hypothesis, that none covalent bonds between the silicon and the OH- groups of cellulose, hemicelluloses or lignin could be created in the cell-walls of the silicon-modified woods.

Degradation of wood fire retardant by UV assisted biomimetic oxidation over Cu([H4]salen) using BDE209 as a model

This work aimed to study mineralization and detoxification of BDE209 by biomimetic oxidation. The removal rate (RR) of BDE209 of process was comparatively investigated in the presence of UV radiation using immobilized Cu([H4]salen) complexes (Cu([H4]salen)/IM and Cu([H4]salen)/SB) as biomimetic catalysts. Their neat and [H2]salen complexes were compared towards BDE209 degradation. UV effects were evaluated according to RR. Ecotoxicities were measured for treated BDE209 solutions and explained in terms of total organic carbon (TOC). The results showed that UV-Cu([H4]salen)/SB process evidently gave high RR and low ecotoxicity in BDE209 degradation, indicating a significant superiority of biomimetic catalysis, complex reduction and immobilization and UV radiation.