Comparison of resistance improvement to fungal growth on green and conventional building materials by nano-metal impregnation

The fungal growth without nano-metals on test materials did not show that green materials were more prone to fungal growth. After nano-metal treatment, the observed order of fungal growth resistance of nano-metals at their highest selected concentrations on test materials was nano-zinc = nano-copper > nano-silver for WF and GWF, nano-zinc > nano-silver = nano-copper for GB, nano-zinc > nano-silver > nano-copper for GGB, CSB and GCSB, nano-silver > nano-copper = nano-zinc for MFC, and nano-silver > nano-copper > nano-zinc for GMFC. Nano-zinc seems to be the most favorable nano-metal for wood and wood composite materials. Green materials were less resistant to fungi attack relative to their conventional counterparts treated by nano-metals, particularly GWF and WF. All test nano-metals failed to provide complete protection against fungal growth on the eight test BMs at the selected concentrations. However, the higher the nano-metal concentration was, the longer the lag period until growth began and fewer fungi grew on the materials.