The invention discloses a preparation method of coffee ground substrate
active carbon. The method comprises the following steps that (a)
coffee grounds are soaked in
distilled water many times, and dried
coffee grounds are obtained through
drying and
filtration; (b) the dried
coffee grounds are put in a container, a
phosphoric acid solution with the
mass percent concentration of 8-12% is added, the using volume amount of the
phosphoric acid solution is 4-6 mL-g-1 based on the
mass of the dried coffee grounds, and after stirring,
ultrasonic vibration lasts for 3-4 hours; after filtering, the coffee grounds are washed to be neutral and dried at 100-110 DEG C, and coffee grounds after
acid treatment are obtained; (c) the coffee grounds after
acid treatment are put in a
muffle furnace for activation, the temperature increasing rate is controlled to 8-12 DEG C-min-1, the temperature is gradually increased to 580-620 DEG C, temperature preservation lasts for 1-2 hours, the coffee grounds arenaturally cooled to the indoor temperature, taken out and washed with
distilled water to be neutral, and after
drying and screening, the coffee ground substrate
active carbon is obtained. According to the coffee ground substrate
active carbon, the coffee grounds are taken as a
raw material, the
phosphoric acid is an activating agent, and the coffee ground substrate active carbon is prepared by utilizing a high-temperature
pyrolysis self-
activation method, and is large in specific surface area, high in adsorption capacity and capable of being used for treating waste water with Cr(VI), adsorbing Cr and preventing and treating heavy
metal pollution.