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Ball milling preparation of spent graphite supported zero-valent iron-copper to degrade tetracycline in water

100%

Hang X. , Wu X. , Song W. , Chen S.

Polish Journal of Chemical Technology

2024

tom Vol. 26, nr 4

56--63

In this study, graphite and copper from spent LIBs were used to prepare graphite supported zero-valent iron-copper (ZVI-Cu/G) by ball milling, to improve the reactivity of ZVI. The structure, composition, morphology, and properties of ZVI-Cu/G were fully analyzed. The removal performances of tetracycline by ZVI-Cu/G were tested under different reaction conditions. Graphite and copper improve the dispersion, specific surface area and reactivity of the material. Operational factors, material dosage of 1 g/L, initial pH of 3, temperature of 25 °C, and H2O2 concentration of 2 mM, contribute to the best tetracycline removal rate, being 100% in 30 min for 30 mg/L tetracycline solution. The reaction data fits a pseudo first-order model. Tetracycline removal rate was as high as 90% even in the 3rd round of reuse. This study reports a novel ZVI material with high tetracycline removal rate.

Synthesis of nanoscale zero-valent iron doped carbonized zeolitic imidazolate framework-8 for methylene blue removal in water

75%

Chen S. , Qiao L. , Feng X. , Huang Y. , Gao G. , Guan J. , Lin D.

2023

tom Vol. 25, nr 1

12--19

Nanoscale zero-valent iron-doped carbonized zeolitic imidazolate framework-8 (nZVI/CZIF-8) was prepared by carbonation of ferric nitrate and ZIF-8 at 800 °C and used as an adsorbent to remove methylene blue (MB) from water. The synthesized nZVI/CZIF-8 has a specific surface area of 806.9 m2/g, a pore volume of 0.86 cm3/g and an nZVI content of 1.35%, respectively. Both the nZVI/CZIF-8 and CZIF-8 have identical functional groups of O-H, C-H and C=C. With the increase of CZIF-8 size, MB removal rate increased. The doping of nZVI increased the MB removal percentage from 74.5% for ZIF-8 to 96.2% within 80 min for nZVI/CZIF-8. The MB removal percentage increased with the dosage of nZVI/CZIF-8. The MB adsorption with the adsorbents conforms to the Freundlich adsorption isothermal model and the removal rate fitted well to a pseudo-first-order model. The results demonstrate the feasibility of synthesizing high active and stable nZVI/CZIF-8 particles.

A tool orientation smoothing method for five-axis machining to avoid singularity problems

75%

Cui C. , Zhu Z. , Chen S. , Zheng Q. , Chai J. , Li X.

Journal of Theoretical and Applied Mechanics

2023

tom Vol. 61 nr 1

89--102

In numerically controlled grinding of aeroengine blades, a sharp change in a rotating shaft caused by a singular zone greatly reduces grinding precision and quality. This paper proposes an algorithm to optimize the tool-path that combines optimization of the C-axis rotation angle, a modification to the tool orientation and adjustments to the tool position by taking a four-array machine tool with two rotational axes (B-axis and C-axis) as an example. The algorithm was verified using VERICUT software, furthermore, in machining experiments, the rotation amplitudes of the rotary axis in singular areas was effectively reduced, which ensured grinding quality of blades.