Stabilization mechanism of heavy metals in MSW incineration fly ash using organic chelating-phosphate complex agent
YANG Guang1,, BAO Bing2, DING Wenchuan1,,, YAN Zhuoyi1, LIU Jialie3 1.Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China 2.Chongqing Landscape Architectural Science Institute, Chongqing 401329, China 3.Chongqing Environmental Engineering Evaluation Center, Chongqing 401121, China
Abstract:Municipal solid waste (MSW) incineration fly ash were stabilized by combining dithiocarbamate chelating resin agent (FACAR) with triple superphosphate (TSP). For the pristine and stabilized fly ash, BCR sequential extraction procedure, X-ray diffraction (XRD) analysis and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) measurement were performed to explore the mechanism of heavy metals stabilization. The results indicated that 5% FACAR addition could effectively stabilize heavy metal Pb, Cd and Ni in fly ash, and the leaching concentrations of Pb, Cd and Ni were lower than the limits stipulated in Standard for Pollution Control on the Landfill Site of Municipal Solid Waste (GB 16889-2008). Moreover, the fly ash treated by the combination of 3% FACAR and 3% TSP could meet the requirements of GB 16889-2008 and the cost obviously decreased, its surface porosity was reduced significantly, and the unstable forms of Pb, Cd and Ni changed to stable ones. The stabilization of Pb, Cd and Ni was mainly ascribed to the joint mechanisms of chelation, co-precipitation and adsorption. Furthermore, the sulfur functional groups contained in the FACAR were the main factors affecting the heavy metals stabilization, which could be preferentially bonded with the sulfur functional groups. Key words:fly ash/ heavy metals/ phosphate/ organic chelating agent/ stabilization mechanism.
图6醋酸缓冲溶液法浸出FACAR和TSP复合稳定后飞灰的电镜扫描图及其EDS检测位点 Figure6.SEM images and analysis positions of EDS on FACAR/TSP stabilized fly ash before and after leaching by acetic acid buffer solution
LUNDTORP K, JENSEN D L, SORENSEN M A, et al. Treatment of waste incinerator air-pollution-control residues with FeSO4: Concept and product characterization[J]. Waste Management and Research, 2002, 20(1): 69-79. doi: 10.1177/0734242X0202000108
[7]
THAWORNCHAISIT U, POLPRASERT C. Evaluation of phosphate fertilizers for the stabilization of cadmium in highly contaminated soils[J]. Journal of Hazardous Materials, 2009, 165(1): 1109-1113.
HUANG W J, LO J S. Synthesis and efficiency of a new chemical fixation agent for stabilizing MSWI fly ash[J]. Journal of Hazardous Materials, 2004, 112(1): 79-86.
[10]
ZHANG H J, YU Y, NI Y W, et al. Stabilization of heavy metals in municipal solid waste incineration fly ash with the thiol collectors[J]. Environmental Science, 2007, 28(8): 1899-1904.
[11]
WANG F H, ZHANG F, CHEN Y J, et al. A comparative study on the heavy metal solidification/stabilization performance of four chemical solidifying agents in municipal solid waste incineration fly ash[J]. Journal of Hazardous Materials, 2015, 300: 451-458. doi: 10.1016/j.jhazmat.2015.07.037
[12]
WANG J B, QIN R X. Organic complex chelators for stabilization of heavy metals in fly ash[J]. Advanced Materials Research, 2014, 864: 217-220.
MIZUTANI S, VANDERSLOOT H A, SAKAI S. Evaluation of treatment of gas cleaning residues from MSWI with chemical agents[J]. Waste Management, 2000, 20(2/3): 233-240.
RAURET G, LOPEZSANCHEZ J F, SAHUQUILLO A, et al. Improvement of the BCR three step sequential extraction procedure prior to the certification of new sediment and soil reference materials[J]. Journal of Environmental Monitoring, 1999, 1(1): 57-61. doi: 10.1039/a807854h
ZHAO Y C, SONG L J, LI G J. Chemical stabilization of MSW incinerator fly ashes[J]. Journal of Hazardous Materials, 2002, 95(2): 47-63.
[25]
JIANG J G, XU X, WANG J, et al. Investigation of basic properties of fly ash from urban waste incinerators in China[J]. Journal of Environmental Sciences, 2007, 19(4): 458-463. doi: 10.1016/S1001-0742(07)60076-X
1.Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China 2.Chongqing Landscape Architectural Science Institute, Chongqing 401329, China 3.Chongqing Environmental Engineering Evaluation Center, Chongqing 401121, China Received Date: 2018-11-26 Accepted Date: 2019-03-22 Available Online: 2019-08-06 Keywords:fly ash/ heavy metals/ phosphate/ organic chelating agent/ stabilization mechanism Abstract:Municipal solid waste (MSW) incineration fly ash were stabilized by combining dithiocarbamate chelating resin agent (FACAR) with triple superphosphate (TSP). For the pristine and stabilized fly ash, BCR sequential extraction procedure, X-ray diffraction (XRD) analysis and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) measurement were performed to explore the mechanism of heavy metals stabilization. The results indicated that 5% FACAR addition could effectively stabilize heavy metal Pb, Cd and Ni in fly ash, and the leaching concentrations of Pb, Cd and Ni were lower than the limits stipulated in Standard for Pollution Control on the Landfill Site of Municipal Solid Waste (GB 16889-2008). Moreover, the fly ash treated by the combination of 3% FACAR and 3% TSP could meet the requirements of GB 16889-2008 and the cost obviously decreased, its surface porosity was reduced significantly, and the unstable forms of Pb, Cd and Ni changed to stable ones. The stabilization of Pb, Cd and Ni was mainly ascribed to the joint mechanisms of chelation, co-precipitation and adsorption. Furthermore, the sulfur functional groups contained in the FACAR were the main factors affecting the heavy metals stabilization, which could be preferentially bonded with the sulfur functional groups.
下载: 
点击查看大图
