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Prediction and management of soil antibiotic contamination issues have gained popularity in recent years. In order to understand the effect of activated carbon on the migration of antibiotics in soil at different temperatures, the vertical migration mechanism of oxytetracycline hydrochloride in charcoal soil was studied. Based on soil column test and numerical simulation, the results indicated that adding low content of activated carbon into soil can obviously enhance the adsorption of antibiotics in soil and inhibit the migration of antibiotics in soil. Hydrus-1D software was used to run numerical simulations, with the adsorption partition coefficient having the most impact on the outcomes. The adsorption distribution coefficient is corrected by theoretical value and inversion value, the value of \({\phi }\) is 0.88.

The structure of polyolefin has an important influence on its performance and application. Ethylene/1-hexene copolymerization is one of the important ways to control the structure of the polyolefin. However, research on the ethylene/1-hexene copolymerization catalyzed by nickel complexes with different steric ligands remains to be refined. Here, three α-diimine nickel catalysts are used to study the ligand effect on catalytic performance in the ethylene/1-hexene copolymerization. Reaction activity, molecular weight, phase-transition temperature and branching density of the resultant copolymer are measured to evaluate the catalytic performance. The results indicate that the steric ligands could exert great effect on the copolymerization. As for the chemical valance of Ni species, detailed EPR demonstrate that the presence of excess co-catalyst can reduce Ni(II) to the lower valance and affect the catalytic performance.

In this study, based on α-diimine-Ni(II) complex/MAO catalytic system, 1-octene was introduced into polyethylene chain to change the microstructure. The effects of reaction temperature, Al/Ni ratio and concentration of 1-octene on the catalytic effect were investigated. Furthermore, the differences between α-olefin homopolymerization and ethylene/α-olefin copolymerization were compared, and the differences between ethylene insertion and α-olefin insertion catalyzed by α-diimine-Ni(II) complex were studied. α-Diimine-Ni(II) complex tends to catalyze ethylene polymerization to form highly branched segments and catalyze α-olefin polymerization to form relatively linear segments due to the “chain walking” ability. The results of mechanical tests show that the synthesized ethylene/1-octene copolymers are polyolefin elastomers with excellent tensile properties. EPR was also employed to analyze the formation of Ni(I) species in the catalytic system and the catalytic mechanism.