| CPC B01J 20/24 (2013.01) [B01J 20/3021 (2013.01); B01J 20/3071 (2013.01); B01J 20/3078 (2013.01); B01J 20/3085 (2013.01); B09C 1/08 (2013.01); C01B 32/05 (2017.08)] | 5 Claims |
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1. A preparation method of a carbon fixation material for adsorbing heavy metals in soil, comprising:
step 1, processing agricultural and forestry waste to obtain biochar;
step 2, pretreating the biochar with ferric chloride to obtain pretreated biochar;
step 3, reacting a mercapto silane coupling agent with the pretreated biochar to obtain modified biochar; and
step 4, mixing the modified biochar, calcium silicate, aluminum sulfate, hydroxymethyl cellulose and urea evenly in proportion to obtain the carbon fixation material for adsorbing heavy metals in soil;
wherein a specific method of the step 1 comprises: washing the agricultural and forestry waste with distilled water to remove impurity to obtain washed waste, pyrolyzing the washed waste at a temperature range of 450° C. to 500° C. in a closed environment for 2-3 h to obtain pyrolyzed waste, and grinding the pyrolyzed waste until a particle size of the pyrolyzed waste is smaller than 1.5 mm, to thereby obtain the biochar;
wherein a specific method of the step 2 comprises: adding the biochar into a ferric chloride solution for ultrasonicating for 30-50 min to obtain a first mixture, adjusting a power of hydrogen (pH) of the first mixture to 2-3, stirring the first mixture with the pH of 2-3 for 2-4 h, followed by filtering, washing and drying to obtain the pretreated biochar; and
wherein a specific method of the step 3 comprises: adding the pretreated biochar, the mercapto silane coupling agent, ethanol and deionized water into a first reactor to obtain a third mixture, stirring the third mixture to react for 6-8 h to obtain a first reacted mixture, adjusting a pH of the first reacted mixture to 7-9, continuously stirring the first reacted mixture with the pH of 7-9 to react for 6-8 h, followed by filtering, washing, drying to obtain a solid mixture, and grinding the solid mixture until a particle size of the solid mixture is smaller than 1.5 mm, to thereby obtain the modified biochar;
wherein the carbon fixation material for adsorbing heavy metals in soil comprises the following materials in parts by weight:
40-50 parts of the modified biochar, 10-15 parts of the calcium silicate, 5-8 parts of the aluminum sulfate, 1-3 parts of the hydroxymethyl cellulose and 3-5 parts of the urea;
wherein the mercapto silane coupling agent comprises a structure represented by a formula A expressed as follows:
 wherein the mercapto silane coupling agent is prepared by the following steps:
adding thiourea and chloromethylphenethyltris(trimethylsiloxy)silane into a second reactor to obtain a second mixture, heating the second mixture to a temperature range of 160° C. to 180° C. to obtain a heated mixture, performing reflux reaction on the heated mixture for 6-8 h to obtain a refluxed mixture, cooling the refluxed mixture to a temperature range of 80° C. to 90° C., and continuously introducing ammonia gas into the second reactor until no reaction occurs to obtain a second reacted mixture, filtering the second reacted mixture to obtain a filtrate, decompressing and distilling the filtrate to obtain a fraction at a temperature range of 190° C. to 200° C.; wherein the fraction at the temperature range of 190° C. to 200° C. is the mercapto silane coupling agent.
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