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11Trace elements (TEs) emitted from coal-fired power plant has caused widespread 12 concern. The onsite investigation of the TEs emission from a Chinese 660MW 13 pulverized coal (PC) boiler equipped with SCR, ESP, WFGD and WESP was 14 conducted by using US EPA Method 29. Simultaneous sampling of the coal, bottom 15 ash, ESP ash, flue gas and by-products from WFGD and WESP process was 16 performed. Results show that TEs mass balance rates for the entire system, furnace 17 and each air pollution control device (APCD) are in acceptable range of 70-130%, 18 which confirms the validity and reliability of the field test data. The studied TEs are 19 mainly distributed in bottom and ESP ash with the ratio of 2.11%-12.15% and 20 87.83%-97.83% respectively while little amount of them exists in WFGD, WESP and 21 stack. Coal combustion by-products like bottom ash and gypsum have little influence 22 on soil from the perspective of TEs while more attention should be paid to Ni, Zn and 23 Cd in the ESP ash. Waste water from WFGD should be treated carefully especially 24 for Cr and Mn. WESP waste water has no influence on ground water except Mn, Ag 25 and Sb. Zn, Ni and Sb prefer to enrich in ESP ash while accumulation of Mn occurs in 26 bottom ash. Ba is enriched in both bottom and ESP ash. ESP has great removal 27 efficiency for TEs with value exceeding 99.87%. Both WFGD and WESP are capable 28 to capture TEs, which results in the overall removal rate across ESP + WFGD + 29 WESP more than 99.90%. TEs concentration in the flue gas emitted from the stack is 30 extremely low with the range of 0.00-1.33 µg/m 3 . The ultra-low emission (ULE) 31 coal-fired power plant equipped with SCR + ESP + WFGD + WESP has good effects 32 on TEs emission control.33

The absorption rates of NO into aqueous solutions of NaClO 2 blended with Na 2 CO 3 were investigated in a stirred reactor. The experimental results showed that the reaction rate could be expressed as N NO 0:for a second-order reaction rate constant between NO and NaClO 2 , k mn = 5.79 · 10 15 exp(-5557.26/T), was obtained. The addition of Na 2 CO 3 into the solution of NaClO 2 decreased the reaction rate constant. The optimal absorption conditions involved a NO concentration of 540 ppm, NaClO 2 concentration of 50 mol m -3 , Na 2 CO 3 concentration of 10 mol m -3, temperature of 333 K and O 2 concentration of 4 %, which were determined by an orthogonal experiment. Under these optimal conditions, it was possible for the absorption rate to reach up to 1.9271 · 10 -5 mol/(s m 2 ).

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