Enhancing the growth performance of fine particles in supersaturated water vapor environment (SWVE) is an important means to further improve the removal efficiency of fine particles in coal-fired flue gas . In this paper, the growth performance of fine particles was strengthened by direct coupling magnetic field (MF) and heterogeneous condensation technology. The particle growth and measurement experimental platform was used to measure the effect of MF on the growth performance of heterogeneous condensation for high-concentration particles under different particle concentration and residence time. Our results show that the growth performance of insoluble submicron particles can be improved by direct coupling MF and heterogeneous condensation technology. After adding the MF with an intensity of 61.1 mT, the number of submicron particles decreases, and the number of particles with particle size greater than 2.1 μm increases in grown particles. At the same particle concentration and supersaturation , the arithmetic mean diameter of the grown particles in the SWVE with MF increases by 0.45%–2.32%, compared with that without magnetic field. Under the same residence time and supersaturation, the arithmetic mean diameter increases by 0.32%–6.89% for the grown particles in the SWVE with MF.
Sun Kaixuan,Sun Yuanyuan,Gao Bin,Xu Hongxia,Wu Jichun
Retention and transport of sulfonamides (SAs) in subsurface can strongly affect groundwater quality. In this work, a range of laboratory batch sorption and column transport experiments were conducted to determine the effect of cation type in mixed Ca-Na systems on the retention and transport of two typical SAs, sulfadimethoxine (SDM) and sulfacetamide (SCA), in saturated limestone porous media. Column experimental data showed divalent cation Ca 2+ played a more important role than monovalent cation Na + in decreasing the transport of only SDM in co-cation systems in the saturated limestone media. Further, in the single-cation (i.e., including either Ca 2+ or Na + ) system, increasing ionic strength (IS) of either NaCl or CaCl 2 had little effect on SCA transport; however, increasing of IS of CaCl 2 promoted the retention of SDM in the saturated limestone porous media. This is mainly due to the cation bridging effect of Ca 2+ on SDM and limestone. Overall, SDM showed much higher retention in the limestone columns than SCA, which can be attributed to the two SAs’ different physicochemical properties. Moreover, limestone showed stronger ability to retain the two SAs than quartz sand. Findings in this study suggest that cation type and the concentration of certain electrolyte (e.g., CaCl 2 ) as well as medium type play an important role in controlling the environmental fate and transport of antibiotics.
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