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Microstructure and heavy metal adsorption mechanisms of hydrothermally synthesized Al-substituted tobermorite
Due to the properties of tobermorite as a cation exchanger and its potential applications in catalysis, and in hazardous waste disposal, attention has been drawn to the properties of tobermorite. In this study, fresh calcium oxide (CaO), fumed silica powder (SiO2) and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) were used for synthesizing tobermorite with/without aluminum. The suitable synthesis condition was confirmed as 5 h in an autoclave at 180 °C and saturation vapor pressure around 1 MPa, marked as samples T and TA, respectively. The BET surface areas of T and TA were 198.83 and 80.48 m2/g, respectively. The pore sizes were mainly distributed between 100 and 300 nm, and pore volume of TA significantly lower than T. Laser scattering particle analysis indicated that the particle size of T and TA were both distributed between 1 and 100 μm, and the median diameter was 27.41 and 19.44 μm, respectively. These results indicated that the aluminum refined pore structure and particle size. The adsorption effectiveness was affected by adsorbent contents and adsorption time. For both of T and TA, the adsorption effectiveness of Cr6+, Pb2+, and Cu2+ could be higher than 97.62. 96.4, and 94.13%, respectively. The residues after adsorption were further studied by XRD, ATR-IR, and SEM. The results of XRD and ATR-IR showed that there was no other significant phase and functional group, except hydrocerussite (Pb3(CO3)2(OH)2) in T–Pb residue. The results indicate that the uptake of heavy metals (Cr6+, Pb2+, and Cu2+) by T or TA mainly through two ways which are surface complexation and uptake in the interlayer. SEM showed TA has better structural stability with the uptake of heavy metals than T. It indicated that chemical effects were the dominant factor, and physical effect took second place.
Microstructure and heavy metal adsorption mechanisms of hydrothermally synthesized Al-substituted tobermorite
Due to the properties of tobermorite as a cation exchanger and its potential applications in catalysis, and in hazardous waste disposal, attention has been drawn to the properties of tobermorite. In this study, fresh calcium oxide (CaO), fumed silica powder (SiO2) and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) were used for synthesizing tobermorite with/without aluminum. The suitable synthesis condition was confirmed as 5 h in an autoclave at 180 °C and saturation vapor pressure around 1 MPa, marked as samples T and TA, respectively. The BET surface areas of T and TA were 198.83 and 80.48 m2/g, respectively. The pore sizes were mainly distributed between 100 and 300 nm, and pore volume of TA significantly lower than T. Laser scattering particle analysis indicated that the particle size of T and TA were both distributed between 1 and 100 μm, and the median diameter was 27.41 and 19.44 μm, respectively. These results indicated that the aluminum refined pore structure and particle size. The adsorption effectiveness was affected by adsorbent contents and adsorption time. For both of T and TA, the adsorption effectiveness of Cr6+, Pb2+, and Cu2+ could be higher than 97.62. 96.4, and 94.13%, respectively. The residues after adsorption were further studied by XRD, ATR-IR, and SEM. The results of XRD and ATR-IR showed that there was no other significant phase and functional group, except hydrocerussite (Pb3(CO3)2(OH)2) in T–Pb residue. The results indicate that the uptake of heavy metals (Cr6+, Pb2+, and Cu2+) by T or TA mainly through two ways which are surface complexation and uptake in the interlayer. SEM showed TA has better structural stability with the uptake of heavy metals than T. It indicated that chemical effects were the dominant factor, and physical effect took second place.
Microstructure and heavy metal adsorption mechanisms of hydrothermally synthesized Al-substituted tobermorite
Guo, Xiaolu (Autor:in) / Shi, Huisheng
2017
Aufsatz (Zeitschrift)
Englisch
Structural stability , Al-substituted tobermorite , Operating Procedures, Materials Treatment , Theoretical and Applied Mechanics , Chemical effects , Hydrothermal treatment , Silicon dioxide , Pore size distribution , Calcium silicates , Aluminum , Materials Science, general , Particle size distribution , Building Materials , Interlayers , Lead (metal) , Heavy metals , Cation exchanging , Copper , Synthesis , Structural Mechanics , Fumed silica , Civil Engineering , Adsorption , Autoclaving , Surface chemistry , Calcium oxide , Lime , Hazardous wastes , Porosity , Catalysis , Particle size , Nitrates , Engineering , Vapor pressure , Waste disposal , Functional groups
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