Obstacles such as aggregation and low activity of micron zero-valent iron in pollutant treatment could be overcome by sulfidation and biochar support. Ball milling is a promising method for the preparation of iron-based composites but the milling atmosphere is critical. To maximize the reactivity and identify the effects of ball mill atmosphere, ball milling technology under wet and dry atmosphere was applied to prepare composites from mZVI, Na 2 S 2 O 4 , and pine wood biochar (BC) for Cr(VI) removal. The results showed that S-mZVI/BC-wet was highly dispersible with more FeS 2 coverage and thus more efficient on Cr (VI) removal than S-mZVI/BC-dry (99.9 % removal in 80 min vs. 87.9 % removal in 24 h) at the optimum Fe: C mass ratio (1:1), S: Fe molar ratio (1:10), and reaction conditions. Cr(VI) was adsorbed by a spontaneous, endothermic mechanism that combined physisorption and chemisorption. The reduction process was vulcanization efficiency and iron cycle dependent. Reduction outperformed adsorption on the Cr(VI) removal and high reduction rateswere electron-selectively related (59.15 % for S-mZVI/BC-wet and 46.72 % for S-mZVI/BC-dry), implying S-mZVI/BC-wet was more capable. S-mZVI/BC-wet presented excellent anti-ageing property and slightly inferior regeneration performance. In conclusion, the composite prepared by wet ball milling have excellent performance in rapid and complete removal of Cr(VI), and S-mZVI/BC-wet has superior potential in acidic wastewater treatment.
This research supplied a “cleaner-production” way to produce “clean-label” quinoa starch-based Pickering emulsifier with excellent emulsifying properties. The effects of dry ball-milling time and speed on the multi-scale structures and emulsifying properties of quinoa starch were studied. With increasing ball-milling time and speed, particle size first decreased and then increased, the crystallinity, lamellar structure and short-range ordered structure gradually decreased, and contact angle gradually increased. The increased contact angle might be related to the increased oil absorption properties and the decreased water content. The emulsification properties of ball-milled quinoa starch (BMQS)-based Pickering emulsions increased with the increase in ball-milling time and speed, and the emulsions of BMQS-4 h, 6 h, 8 h, and 600 r reached the full emulsification state. After 120 days’ storage, the oil droplets of BMQS-2 h (BMQS-400 r) deformed, the oil droplets increased, and the emulsification index decreased. The emulsification index and the oil droplets of BMQS-4 h, 6 h, 8 h and 600 r-based emulsions did not show obvious changes after storage, indicating the good emulsifying stability of these BMQS-based emulsions, which might be because that the relatively larger amount of starch particles that dispersed in the voids among the oil droplets could act as stronger network skeletons for the emulsion gel. This Pickering emulsifier was easily and highly efficiently produced and low-cost, having great potential to be used in the food, cosmetic and pharmaceutical industries.
危险品化学品经营许可证（带存储）