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Here, the adsorption and diffusion of CH4 and the intruding gases in coal were systematically simulated via Monte Carlo. The adsorption selectivity of carbon dioxide over methane (S CO2 /CH4 , >1) decreases significantly at P < 6 MPa and is kept stable when P > 6 MPa. However, S N2 /CH4 (<1) monotonously increases with the increasing pressure, temperature, and bulk mole fraction (BMF) of N2. Both the cross exchange (D i,j ) and diagonal diffusion (D i,i ) coefficients in the nCO2 + mCH4 and nN2 + mCH4 systems gradually increase with the increasing temperature. D i,j is far higher than D i,i for these two systems, indicating the weaker coupling strength of gas–gas interactions than the gas–coal interactions. D 11 1 (or D 11 2) increases while D 22 1 (or D 22 2) decreases with the increase of CO2 (or N2) BMF. The swelling ratios of nCO2 + mCH4 and nN2 + mCH4 increase slightly at temperatures lower than 338 K and significantly at temperatures higher than 338 K, and both of them are positively related to BMFs of CO2 and CH4, respectively. Both S CO2/CH4 d and S N2/CH4 d increase with the increasing BMF of carbon dioxide and methane, respectively, indicating that the replacement effects of CO2 and N2 engineering are weightily related to the mole fractions of the invading gases. S CO2/CH4 d first increases (≤398 K) and then decreases (398 < T < 438 K). Concerning the geological conditions, the optimization injection depths were 800–1100 m (7.94–10.88 MPa) and 600–900 m (5.98–8.92 MPa) for carbon dioxide and nitrogen, respectively.

With the intensive and large-scale development of livestock and poultry breeding industry in China, the amount of livestock and poultry waste is increasing year by year, and the environmental pollution caused by it is increasingly serious. There are a lot of heavy metals in livestock and poultry waste, which not only cause serious pollution to the environment, but also reduce the safety of agricultural products, and pose a threat to human health. Therefore, the livestock and poultry waste must be treated by appropriate technology, after removing heavy metals, it can be used as a resource in the future. This paper summarizes the technologies of heavy metal treatment of livestock and poultry waste, and puts forward suggestions for the development of heavy metal treatment technology of livestock and poultry waste.

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