Porous biochar for improving severe pollution and preparation method therefor
A porous biochar for improving heavy pollution and a method for producing the same. Said porous biochar is prepared as follows: arrowhead, which has excellent enrichment of lead, is used to absorb heavy metal lead in polluted water or artificial wetlands, simultaneously absorb heavy metal cadmium, thereafter is dried and treated as a biomass, and then the biomass is calcined in stages with a passivating agent in a high temperature environment, so as to heavy metals such as lead and cadmium be stably coated or enriched in a biochar, which is mixed with Pseudomonas aeruginosa having high resistant, to obtain the porous biochar; the porous biochar has high specific surface area, high porosity and excellent mechanical properties, is very stable under different acid-base environments and oxidizing conditions.
1 . A production method of a porous biochar for improving heavy metal pollution, wherein the method comprises:
step 1, producing a biochar:
step 1-1, planting a plant in water or artificial wetland polluted by heavy metals;
step 1-2, harvesting the plant grown in step 1-1 to prepare a biomass;
step 1-3, calcining the biomass prepared in step 1-2 with a passivating agent to obtain the biochar;
step 2, mixing the biochar with microorganism;
step 2-1, acclimating the microorganism;
step 2-2, mixing the biochar with the microorganism acclimated in step 2-1 to obtain the porous biochar;
wherein the microorganism is Pseudomonas aeruginosa ; the porous biochar has a dissolution rate of lead from 0.81% to 0.98% and a dissolution rate of cadmium from 0.72% to 0.95%.
2 . The method according to claim 1 , characterized in that, in step 1-1, the plant is an aquatic plant;
said heavy metals include the lead and the cadmium, wherein, a concentration of the lead is lower than 500 mg/L and a concentration of the cadmium is lower than 200 mg/L.
3 . The method according to claim 2 , wherein the aquatic plant is an emergent plant.
4 . The method according to claim 3 , wherein the emergent plant is selected from the group consisting of arrowhead, pampas grass, reed and umbrella sedge.
5 . The method according to claim 4 , wherein the emergent plant is the arrowhead.
6 . The method according to claim 1 , characterized in that, in step 1-2, the plant grown in step 1-1 is harvested, dried, and pulverized, to prepare the biomass.
7 . The method according to claim 1 , wherein said passivating agent is one or more selected from the group consisting of diatomaceous earth, zeolite, and attapulgite.
8 . The method according to claim 7 , wherein said passivating agent is a mixture of the diatomaceous earth, the zeolite, and the attapulgite.
9 . The method according to claim 1 , characterized in that, in steps 1-3, said calcining comprises:
first stage: pyrolysis temperature is 180-300° C., for 2-6 h, and heating rate is 4-8° C./min;
second stage: the pyrolysis temperature is 300-600° C., for 0.5-4 h, and the heating rate is 6-10° C./min.
10 . The method according to claim 1 , characterized in that, said acclimating comprises: pre-expansion culturing Pseudomonas aeruginosa species into 10 8 -10 9 /mL liquid species, and then inoculating and culturing in a medium containing heavy metals including the lead and the cadmium.