Preparation of
nitrogen-
sulfur co-doped
canna flower-based
biochar and a use thereof in the removal of
malachite green in
wastewater. The method comprises: washing,
drying, and pulverizing a collected
canna flower, mixing same with a certain amount of
phosphoric acid in a
beaker, adding an appropriate amount of deionized water, stirring same, loading a feed liquid into a hydrothermal kettle, and then placing same in an oven for
hydrothermal treatment to obtain a
canna flower-based hydrothermal carbon; uniformly mixing hydrothermal carbon
powder with a certain
mass ratio of
thiourea and
molten salt, placing the mixture in a
muffle furnace for firing in air, cooling same with the furnace after firing is completed, finally taking out a sample, separating the
molten salt, performing
acid washing on the
biochar, washing same with
alcohol, washing same with water, and then
drying same to obtain the
nitrogen-
sulfur co-doped canna flower-based
biochar; and using the
nitrogen-
sulfur co-doped canna flower-based biochar to remove
malachite green in
wastewater. Compared with conventional carbon materials, the nitrogen-sulfur co-
doped carbon material prepared by the method has greatly improved removal efficiency for
malachite green in a
water body. In addition, the preparation method provides a way to treat a
biomass waste, saves costs, and realizes
resource utilization of
biomass wastes.