Wang Guanbai, Wang Yi, Guo Yu, Peng Dangcong
School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
Environ Sci Pollut Res Int. 2017 Jan;24(1):264-274. doi: 10.1007/s11356-016-7796-5. Epub 2016 Oct 6.
To lower phosphorus concentration in Xi'an moat, four different phosphorus-locking materials, namely, calcium nitrate, sponge-iron, fly ash, and silica alumina clay, were selected in this experiment to study their effects on water quality and sediment. Results of the continuous 68-day experiment showed that calcium nitrate was the most effective for controlling phosphorus concentration in overlying and interstitial water, where the efficiency of locking phosphorus was >97 and 90 %, respectively. Meanwhile, the addition of calcium nitrate caused Fe/Al-bound phosphorus (Fe/Al-P) content in sediment declining but Ca-bound phosphorus (Ca-P) and organic phosphorus (OP) content ascending. The phosphorus-locking efficiency of sponge-iron in overlying and interstitial water was >72 and 66 %, respectively. Meanwhile, the total phosphorus (TP), OP, Fe/Al-P, and Ca-P content in sediment increased by 33.8, 7.7, 23.1, and 23.1 %, respectively, implying that under the action of sponge-iron, the locked phosphorus in sediment was mainly inorganic form and the phosphorus-locking efficiency of sponge-iron could be stable and persistent. In addition, the phosphorus-locking efficiency of fly ash was transient and limited, let alone silica alumina clay had almost no capacity for phosphorus-locking efficiency. Therefore, calcium nitrate and sponge-iron were excellent phosphorus-locking agents to repair the seriously polluted water derived from an internal source.
为降低西安护城河的磷浓度，本实验选取了四种不同的锁磷材料，即硝酸钙、海绵铁、粉煤灰和硅铝黏土，研究它们对水质和沉积物的影响。连续68天的实验结果表明，硝酸钙对控制上覆水和间隙水中的磷浓度最为有效，其锁磷效率分别>97%和90%。同时，添加硝酸钙导致沉积物中Fe/Al结合态磷（Fe/Al-P）含量下降，但Ca结合态磷（Ca-P）和有机磷（OP）含量上升。海绵铁对上覆水和间隙水的锁磷效率分别>72%和66%。同时，沉积物中的总磷（TP）、OP、Fe/Al-P和Ca-P含量分别增加了33.8%、7.7%、23.1%和23.1%，这意味着在海绵铁的作用下，沉积物中锁定的磷主要为无机形态，且海绵铁的锁磷效率具有稳定性和持久性。此外，粉煤灰的锁磷效率是短暂且有限的，更不用说硅铝黏土几乎没有锁磷能力。因此，硝酸钙和海绵铁是修复严重污染的内源水的优良锁磷剂。
