2.1. Duckweed samples
The samples of dry duckweed were provided by Petroalgae Inc. (Melbourne, Florida, USA) and were used as received. The proximate analysis of dry duckweed is as follows (wt.%): moisture – 3.7; total volatiles (120–950 C) – 78.0 (including volatiles evolved at 120–650 C – 67); fixed carbon – 8.8; ash – 9.5. The ultimate analysis of a dry duckweed sample gave the following (%): C – 39.11; H – 6.13; O – 37.74; N – 5.52; S – 0.67; balance – mineral matter.