Volume 17, No. 4, April 2017, Pages 1105-1116 PDF(515 KB)
Characterization of Inorganic Elements within PM2.5 and PM10 Fractions of Fly Ashes from Coal-Fired Power Plants
Zhiyong Li1, Yaqin Ji2, Huiqiao Ma1, Peng Zhao1, Xiangchao Zeng1, Songtao Liu1, Yunjun Jiang3, Lei Wang1,3, Aiqin Liu3, Huiying Gao1, Fude Liu4, John Kennedy Mwangi5,6
1 School of Environmental Science and Engineering, North China Electric Power University, Baoding 071000, China
2 School of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
3 Central Laboratory of Geology and Mineral Resources of Hebei Province, Baoding 071003, China
4 School of Environmental Science and Safety Engineering, Tianjin University of Technology, Tianjin 300384, China
5 School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
6 Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan
- Inorganic elements were analyzed within PM2.5 and PM10 for power plant fly ashes.
- Contamination levels for 13 heavy metals were determined based on Igeo values.
- Element profiles between any two power plants were similar for PM2.5 or PM10.
- Relative enrichment factors for most elements were found to be lower than 1.30.
In this study 15 fly ash samples were collected from 15 large-scale coal-fired power plants (CFPPs) in China. The samples were then re-suspended through PM2.5 and PM10 inlets and analyzed for the contents of 39 inorganic elements (IEs) using inductively coupled plasma-mass spectroscopy (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). The results show that the particle size distributions for the 15 FAs samples exhibited bimodal patterns. The Ʃ39IEs (g g–1) for the PM2.5 (0.292–0.564) in all the 15 CFPPs were higher than that of PM10 (0.269–0.403). Except for Cu, all the other 38 IEs were more enriched in the PM2.5 with the PM2.5/PM10 ratios being 1.06–1.73. Considering 13 heavy metals, the same orders occurred between PM2.5 and PM10 with Al >> Cr > Zn > Mn > Cu > V > Pb > Sn > Co > As > Sb > Tl > Cd. More attention should be paid to the high contents of Cr in both PM2.5 (1310 mg g–1) and for PM10 (1240 mg g–1) from all 15 CFPPs. 23 IEs for PM10 and 26 IEs for PM2.5 had the geo-accumulation index (Igeo) values higher than 0, indicating different pollution levels for them. On the other hand, there was moderate to extreme levels of pollution for Cr, Zn, Cu, Pb, Sn, Sb, Tl, Cd and Al based on Igeo values. The element profiles for PM2.5 or PM10 from 15 CFPPs were similar based on low coefficients of divergence for PM2.5 (0.254 ± 0.038) and PM10 (0.244 ± 0.054) according to the comparison between any two CFPPs. Most elements with low relative enrichment factors (REF) as less than 0.70 or 0.70–1.30 indicated no or weak condensation occurred for them during coal combustion, while Cr, Cu, Zn, Sn, W and Pb had REF values higher than 1.30 indicated that significant condensation occurred for these elements.
Coal-fired power plant; Inorganic elements; Fly ash; PM2.5; PM10.