Utilization of Al-/Fe-/Si- Ceramic Matrices for Cadmium - PowerPoint PPT Presentation

School of Environmental Science and Engineering Guangzhou University Utilization of Al-/Fe-/Si- Ceramic Matrices for Cadmium Detoxification in Wastes Minhua Su, Lingjun Kong, Jinfeng Tang, Hongguo Zhang Yu Liu, Diyun Chen Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources Linköping University – Guangzhou University Research Center on Urban Sustainable Development School of Environmental Science and Engineering Guangzhou University, Guangzhou, 510006, China Dr. Minhua Su, E-mail: mhsu@gzhu.edu.cn

Guangzhou University (GZU) Being to be High- Comprehensive level Guangdong Guangzhou Guangzhou City Province University (GZU) GZU has 27 schools and enjoys a comprehensive variety of disciplines including philosophy, law, education, literature, history, science, engineering, economics, administration and arts. Website: http://english.gzhu.edu.cn/index.htm 2

Cadmium Kidney damage Skeleton deformation Main routes for entry of cadmium into the food chain and uptake by human. (Vromman, V., et al., 2008)  Since 1990s, Cd was classi fi ed as a group 1 Lung cancer carcinogen (Program 2014) 3

Cadmium Production and Utilizations Global production of refined cadmium, 1950-2000. (International Cadmium Association (ICdA), 2002) Batteries Pigments Coating Stabilizer Alloys and solar cell Trends in Cadmium Consumption from 2005 through 2010. (ICdA, 2013) 4

Cadmium-Laden Sludge Discharged Transported Precipitated Production/After used Water body Sediment/Sludge Incidentally/intentionally Difficult to discharged! remediate! 20 tons of the cadmium discharged into Liujiang river(Guangxi, China) by a Mining plant, causing severe cadmium pollution affecting A ¥ 40.7 billion project (began in 1979) to up to 4 million people. (Reported restore cadmium contaminated farmland in in January, 2012) the Jinzu River basin, Japan. (Reported in March, 2012) 5

Common Treatment of Cadmium Bearing Waste  Solidification/stabilization (S/S) process Montmorillonite (MMT) and silica (Lee, M.-H., et al., 2005) Bauxite (Miller, B. B., et al., 2004) Cadmium Calcium oxide bearing waste (Miller, B. B., et al., 2006) Kaolin Alumina (Yao, H., et al., 2005) (Kuo, J.-H., et al., 2009) Cement based wastes forms (Polettini, A., et al., 2002) Drawbacks: The need of additional stabilization due to the weak binding ability of sorbents by physical or chemical adsorption. 6

Proposed Technology for Cadmium Stabilization Environmentally Friendly Ceramic Techniques Sintering Process (CSP) Waste-to- Resources Thermally converting them into non-hazardous / less hazardous products. Ceramic products or Sintering With high acidic Iron-rich Aluminum-rich resisting ability materials materials Metal-containing wastes K. Shih, et al. E.S&T., 2005; Y. Tang, et al. E.S&T., 2012 7

Equilibrium Diagrams of Cd-Al-O and Cd-Fe-Mg-O Systems Cd-Fe-Mg-O system (Bashkirov and Kornilova 1980) Cd-Al-O system (Colin, 1968) SiO SiO 2 Gamma-Al 2 O 3 Hematite 8

Sample Preparation, Characterization and Evaluation CdO Milled & Dried Mixtures Major characterization Matrices Pelletized at and analysis techniques Cd-Al-O phase ~250 Mpa Stoichiometric Microstructure Sintering observation ratios of Cd/Al Pellets Fired pellets SEM/TEM and Cd/Fe. Qualitative analysis Ground PXRD Quantitative analysis Rietveld CdO + γ -Al 2 O 3 γ -Al 2 O 3 Powder refinement CPLT + ICP Stabilization effect evaluation 9

Quantification Quality Evaluation for QXRD analysis      Y Y  2 w Y ( Y ) o m , c m , m o m , c m , "R-pattern", R , R "R-weight pattern", R , R  p p wp wp 2 Y w Y m o m , o m ,      2 R w Y ( Y ) M P   wp  m o m , c m , 2 "R-expected", R , R "Goodness of fit", GOF, GOF chi  exp exp  2 w Y R M P m o m , exp Incorporation Efficiency Evaluation wt.% of Aluminate or Ferrite MW of Aluminate or Ferrite  TR(%) wt.% of Aluminate or Ferrite wt.% of CdO  MW of Aluminate or Ferrite MW of CdO Leached Metals Normalization � � �� � �� �� �� �� � �� ��� � �� ����� 10

Cadmium-hosting Product Phase Formation via Sintering withAl-/Fe- Ceramic Matrices CdO + 2 γ -Al 2 O 3 → CdAl 4 O 7 (Monoclinic structure) CdO + α -Fe 2 O 3 → CdFe 2 O 4 (Spinel) Incorporation Efficiency Transformation ratios wt.% of Aluminate or Ferrite MW of Aluminate or Ferrite  TR(%) wt.% of Aluminate or Ferrite wt.% of CdO  MW of Aluminate or Ferrite MW of CdO The transformation ratios (TR, %) for cadmium incorporation into CdAl 4 O 7 monoclinic structure and CdFe 2 O 4 spinel. 11

Leachability of CdAl 4 O 7 and CdFe 2 O 4 Formation of robust crystalline structures CdO + 2 γ -Al 2 O 3 → CdAl 4 O 7 (Monoclinic structure) CdO + α -Fe 2 O 3 → CdFe 2 O 4 (Spinel) Detoxification of the hazardous wastes Leached at constant pH 4.0. �� � / �Cd �� �� � molar ratio of 4.0 +  2+ CdO + 2H Cd + H O �Al ���� (s) (eq) (eq) 2 �� � / �Cd �� �� � molar ratio of 2.0  + 2+ 3+ CdAl O + 14H Cd + 4Al + 7H O �Fe ���� 4 7(s) (eq) (eq) (eq) 2 +  2+ 3+ CdFe O + 8H Cd + 2Fe + 4H O 2 4(s) (eq) (eq) (eq) 2 12

Leaching Behavior of CdAl 4 O 7 and CdFe 2 O 4 �� � 3OH ���� � am � Al�OH� ���� ↔ Al ���� < 4.0 �� � 3OH ���� � am � Fe�OH� ���� ↔ Fe ���� At pH 4.0 �� ] should be 6.3×10 -2 M (1701 mg/L), [ Al ���� << 2.0 �� ] should be 1.05×10 -5 M (0.59 mg/L), [ Fe ���� The [Al]/[Cd] molar ratios in CdAl 4 O 7 leachates and [Fe]/[Cd] molar ratios in CdFe 2 O 4 leachates. Incongruent dissolution The (a) soluble Cd and Al concentrations in the leachates of CdAl 4 O 7 monoclinic structure and (b) the soluble Cd and Fe concentrations in the leachates of CdFe 2 O 4 spinel. 13

Cadmium-hosting Product Phase Formation via Sintering with Si-rich Ceramic Matrices CdO + SiO 2 → CdSiO 3 2CdO + SiO 2 → Cd 2 SiO 4 3CdO + SiO 2 → Cd 3 SiO 5 XRD patterns of sintered (a) CdO + silica fume and (b) CdO + a-quartz samples with various Cd/Si molar ratios (Cd/Si molar ratio = 1.0, 2.0, and 3.0) at 950 ºC for 3 h. Views of sintered CdO + silica fume and CdO + α -quartz samples with Cd/Si molar ratios ( Г = 1.0, 2.0, and 3.0) at 950 ° C for 3 h.

Efficiency of Cadmium Incorporation into Cadmium Silicates With silica fume With quartz Cd/Si = 1.0 Cd/Si = 1.0 With silica fume With quartz Cd/Si = 2.0 Cd/Si = 2.0 With silica fume With quartz Cd/Si = 3.0 Cd/Si = 3.0 15

Leachability of CdO, CdSiO 3 , Cd 2 SiO 4 and Cd 3 SiO 5 16

Summary CdO + 2 γ -Al 2 O 3 → CdAl 4 O 7 (Monoclinic structure) CdO + α -Fe 2 O 3 → CdFe 2 O 4 (Spinel) Su et al., EP, 2018 A successful reduction of cadmium under acidic environments, identifying a promising and safe avenue for cadmium-laden sludge treatment. 17

Recent Publications 1. Su, Su, M.H. M.H., Liao, C.Z., Chan, T.-S., Shih, K., Xiao, T.F., Chen, D.Y., Kong, L.J.; Song, G. Incorporation of Cadmium and Nickel into Ferrite Spinel Solid Solution: XRD and EXAFS Study. En Envir vironmental nmental Science cience & Tec echnology hnology , 20 2018, 52, 775-782. 2. 2. Su, Su, M.H., M.H., Liao, C.Z., Chuang, K.H., Wey, M.Y., Shih K.* Cadmium Stabilization Efficiency and Leachability by CdAl 4 O 7 Monoclinic Structure. En Envir vironmental nmental Science cience & Te Technology , 20 2015, 49, 14452-14459. 3. Su, Su, M.H., M.H., Tang ， J., Liao, C.Z., Kong, L. ∗ , Xiao, T., Shih, K., Song, G., Chen, D. ∗ , Zhang, H. Cadmium Stabilization via Silicates Formation: Efficiency, Reaction Routes and Leaching Behavior of Products. En Envir vironmental nmental Pollution ollution , 20 2018, 239, 571-578. Environmental Pollution, 2018, 239, 571-578. 4. Su, 4. Su, M.H. M.H., Liao, C. Z. Lee, P.-H., Li, H.L., Shih K.* Formation and Leaching Behavior of Ferrite Spinel for Cadmium Stabilization. Chemical Chemical Engineering Engineering Science cience , 20 2017,158, 2017, 287-293. 5. 5. Su Su M.H.*, M.H.*,Kong, L.-J. Shih, K. Stabilizing Cadmium into Aluminate and Ferrite Structures: Effectiveness and Leaching Behavior. Journal Journal of Environmental ironmental Management, nagement, 20 2017, 187, 340-346. 18

School of Environmental Science and Engineering Guangzhou University Prof. H.G. Zhang Dr. L.J. Kong Thanks！ 19