Modified Biochar For Hydrogenation Catalyst Application And The Toxicity Assessment Of Biochar Extraction Solutions

Biomass refers to organic matter which directly or indirectly formed by the green plants using solar energy for photosynthesis, and is a kind of important renewable resources. Due to the growing of worldwide energy demand and environmental pollution, biomass has attracted widespread attention due to renewable and environmental friendly properties. Biomass can be converted into energy through hydrogenation cracking, pyrolysis, gasification, liquefaction, and direct combustion,In the high temperature environment, lignocellulosic biomass can be catalytic cracked into small molecules containing benzene ring, which can be used for the preparation of chemicals, petroleum products, etc. Pyrolyzing biomass to produce bio-oil is another way of energy conversion. Biochar is a kind of byproduct of pyrolysis, and it is a kind of solid carbon material with porous structure, often applied into soil remediation and carbon sequestration. But the influence of biochar on soil properties and soil organisms has been controversial. Furthermore, many studies focused on other applications of biochar. For example, modified biochar can be used for the adsorption of organic pollutants and heavy metal; Metal nanoparticles loaded biochar can be used for the catalytic transformation of organic matter, etc.This dissertation investigated 1) the preparation of a mesoporous carbon supported Ni-Mo2C catalyst by one-pot fast pyrolysis of Ni-Mo preloaded sawdust and demonstrated its catalytic performance for hydrogenation of lignin; and 2) the biological toxicity of different sources of biochar when it applied to soil restoration. The main research contents and conclusions are listed as follows:1. Ni-Mo2C/C catalyst was produced through pyrolysis of nickel salt and molybdenum salt impregnated sawdust using a fast pyrolysis device. The catalyst exhibits high catalytic activity in catalytic hydrocracking reaction of lignin, and significantly increase the yield and selectivity of products compared with control and with chemical synthesized molybdenum and nickel catalyst.2. Combined with TEM, XRD, XPS, and GC-MS characterization, the possible reaction mechanism of Ni-Mo2C/C was presented. Nanometer nickel and molybdenum carbide particles can effectively attack carbon oxygen double bond, and the graphitized carbonsubstrate can help the transfer of electron.3. Pyrolysis of different biomass materials (rice husk, sawdust and Acorus calamus) under the same condition can obtained differenrt biochar, and the toxic effects of the biochar extraction solutions to miocroorganism (Pseudomonas aeruginosa), plant (wheat), and animal (Caenorhabditis elegans) were assessed. The results showed that the rice husk and sawdust biochar extraction solutions affect less on biology, but the Acorus calamus biochar extraction solution seriously inhibit the growth of organisms, especially for the Caenorhabditis elegans.