For batches, 20 g of the dried STW was placed into a quartz
tube, and the tube was in turn placed into an electrical tubular
furnace. The furnace was heated gradually until a temperature
of 600 C was reached. The activation was conducted at this
temperature for 120 min, to produce thermally activated carbon
(ACTH). The second type was prepared through placing
20 g of the dried STW into a stainless steel tube which was
placed into an electrical tubular furnace. The sample was
heated gradually in a flow of steam until a temperature of
600 C was attained. The activation was performed at this temperature
for 120 min to produce (ACST). The yield of the produced
carbons was calculated as following