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- Title
稻秆生物炭对水体 Pb<sup>2+</sup> 的吸附特性及机制定量化.
- Authors
金军; 王乙硕; 冼威澄; 刘豪; 党志; 黄飞
- Abstract
The adsorption characteristics of Pb2+ in water by rice-straw biochar were elucidated by adsorption isotherm and kinetics, and the adsorption mechanism of biochar was qualitatively and quantitatively revealed by means of elemental analysis, BET (Brunauer-Emmet-Teller) -N2 specific surface area analysis, Zeta potential, scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), along with the calculation for relative distribution of each adsorption mechanism. The results indicated that the maximum adsorption capacity of Pb2+ by biochar were 233.48 mg / g, 236.00 mg /g and 237. 50 mg / g under the temperatures of 20 ℃, 30 ℃ and 40 ℃, respectively. The experimental data fitted the Langmuir (R²> 0.96) better than the Freundlich isotherm, which suggested monolayer adsorption and a homogeneous distribution of active surface sites. Under the initial concentrations of 50 mg / L, 100 mg / L and 300 mg / L, the equilibrium time of biochar were 30 min, 90 min and 360 min, respectively, which followed the pseudosecond-order mechanism and corresponded to a chemisorption process. The main mechanisms responsible for Pb2+ adsorption by ricestraw biochar included chemical precipitation, cation exchange, Cπ-electron coordination, and functional group complexation, in which the chemical precipitates could be mainly Pb4 (CO3) 2 (SO4) (OH ) 2 and PbCO3, accounting for 47. 15% ~ 50. 81% of total adsorption. Cation exchange also played an important role in the adsorption mechanisms due to high contribution proportions to total adsorption (32. 82% ~ 37. 77%) . Among the adsorption mechanisms, both the Cπ-electron coordination and functional group complexation could contribute 15. 03% to 16. 37% to the total adsorption, but these were overshadowed by the chemical precipitation and cation exchange, accounting for 83. 63% to 84. 92% in the total adsorption. These suggested rice-straw biochar could be an efficient adsorbent for the removal of Pb2+ from aqueous solution.
- Publication
Science Technology & Engineering, 2024, Vol 24, Issue 19, p8362
- ISSN
1671-1815
- Publication type
Article
- DOI
10.12404/j.issn.1671-1815.2305978