The influence of various solvents' polarity in the synthesis of wood biowaste sorbent: evaluation of dye sorption

Wood-based sorbents chemically modified by Al2O3 (WB-Al2O3) were synthesized via solvo-reaction method. The wood residue, a waste material with lignocellulosic structure, was obtained from Quercus robur (oak tree). WB-Al2O3 sorbents were tested for removal of Reactive Blue 19 (RB19) dye. The influence of solvents with different polarity and protic/aprotic nature used in the sorbent synthesis, such as acetone, ethanol, ether, hexane, and methanol, were investigated and the best sorbent capable to remove the highest percentage of dye was determined. To investigate the reason for difference between dye removal efficiency of the synthesized sorbents, the appropriate characterization of the sorbents was done. The highest dye removal efficiency (100%) and the shortest equilibrium time (less than 10 min) were achieved for the WB-Al2O3 sorbent synthesized in less polar solvent - hexane. The sorption kinetics can be described by the pseudo-second-order model. The equilibrium examination showed that the Langmuir model better explained sorption process and the maximal capacity of the WB-Al2O3 was 441.90 mg/g. The present research shows that usage of nature lignocellulosic polymers in the synthesis of the low economically cost sorbents can effectively decrease the water pollution and increase the reusability of wood biowaste.