Xu Chu-Tian, Li Da-Peng, Wang Zi-Liang, Wu Yu-Han, Xu Xin-Peng, Huang Yong
School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China.
Environment Biotechnology Research Institute, Suzhou University of Science and Technology, Suzhou 215009, China.
Huan Jing Ke Xue. 2021 Mar 8;42(3):1424-1432. doi: 10.13227/j.hjkx.202007221.
This study simulated the state of CaO loss after in situ coverage and examined the bottom 2 cm of sediment after restoration. Observations and elemental analysis of the sediment using scanning electron microscopy (SEM) and X-ray energy spectrometry (EDX) were also performed. The CaO remodeling notably changed the structure of the sediment; most of the organic matter and iron-manganese oxide attached to the sediment surface was removed, the porosity of the sediment particles increased, and the Ca content was also increased. CaO remodeling stabilized the endogenous phosphorus in the sediment; total phosphorous (TP) was reduced by approximately 20% and potential active phosphorus content was reduced by approximately 30%. Furthermore, the contents of Ca-P and Res-P were significantly increased. The amount of phosphorus released from the remodeled sediment under anaerobic conditions was significantly lower than the original sediment, indicating that the CaO remodeling greatly reduced the risk of endogenous phosphorus release. The Langmuir model was more suitable than the Freundlich and Dubinin-Radushkevich models for describing the isothermal adsorption behavior of the CaO remodeling, which significantly improved the adsorption capacity of the sediment with respect to phosphate from 1.44 mg·g to 20.91 mg·g. The mechanism of adsorption was switched from chemical adsorption to physicochemical adsorption. In addition, the adsorption kinetics of the CaO remodeled sediment with respect to phosphate could be best described using the quasi-second-order kinetic model.
本研究模拟了原位覆盖后CaO损失的状态，并在修复后检查了底部2 cm的沉积物。还使用扫描电子显微镜（SEM）和X射线能谱（EDX）对沉积物进行了观察和元素分析。CaO重塑显著改变了沉积物的结构；附着在沉积物表面的大部分有机物和铁锰氧化物被去除，沉积物颗粒的孔隙率增加，Ca含量也增加。CaO重塑稳定了沉积物中的内源磷；总磷（TP）降低了约20%，潜在活性磷含量降低了约30%。此外，Ca-P和Res-P的含量显著增加。在厌氧条件下，重塑沉积物释放的磷量明显低于原始沉积物，表明CaO重塑大大降低了内源磷释放的风险。与Freundlich模型和Dubinin-Radushkevich模型相比，Langmuir模型更适合描述CaO重塑的等温吸附行为，这显著提高了沉积物对磷酸盐的吸附容量，从1.44 mg·g提高到20.91 mg·g。吸附机制从化学吸附转变为物理化学吸附。此外，CaO重塑沉积物对磷酸盐的吸附动力学可以用准二级动力学模型最好地描述。
