Ding Yu-Qin, Li Da-Peng, Zhang Shuai, Chen Li-Yuan, Xu Chu-Tian, Chen Shu-Tong, Zhu Qi, Huang Yong
School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China.
Huan Jing Ke Xue. 2020 Apr 8;41(4):1692-1699. doi: 10.13227/j.hjkx.201910010.
Adding biochar from harvested reed to sediments is a new method to control the release of sedimentary phosphorus. Three types of Mg-modified biochars were prepared by pyrolysis of reed modified by magnesium chloride at 300, 450, and 600℃.The phosphate adsorption characteristics of the three types of biochars were analyzed by isothermal adsorption experiments. Biochar MBC-450 with good phosphate adsorption effects was selected as the material for the following experiments. Taking the sediment and overlying water of a campus river as the experimental object, we studied the adsorption of phosphate in overlying water and the control of sedimentary phosphorus by Mg-modified biochar under different dosage modes (mixing and covering). The concentration of DIP in the overlying water could be effectively reduced by biochar mixing and covering, and the accumulative phosphorus adsorption capacity increased by 17.3% (mixing) and 11.7% (covering) compared with that of the control. The control effect of sedimentary phosphorus by biochar mixing was more obvious; the DIP in sedimentary water decreased by 14.7%, 18.9%, and 35.36% from 0-2 cm to 4-6 cm compared with the control. The DIP in sedimentary water decreased by 33.3%, -28.2%, and 12.9% when covered with biochar. Compared with the control, the proportion of NH Cl-P in the sediment of 0-2 cm and 2-4 cm increased by 15% and 15% (mixing) and 12% and 2% (covering), respectively, while BD-P in TP decreased by 7% and 9% (mixing) and 6% and 3% (covering), respectively, and the Al-P in TP decreased by 7% and 6% (mixing) and 7% and -1% (covering), respectively. The other forms of phosphorus did not change significantly. Biochar mixing and covering can both improve the microbial activity in surface sediment, and biochar mixing can improve the microbial activity in deeper sediments more significantly.
向沉积物中添加收割芦苇制备的生物炭是一种控制沉积磷释放的新方法。通过在300℃、450℃和600℃下对经氯化镁改性的芦苇进行热解制备了三种类型的镁改性生物炭。通过等温吸附实验分析了这三种生物炭对磷酸盐的吸附特性。选择具有良好磷酸盐吸附效果的生物炭MBC - 450作为后续实验材料。以某校园河流的沉积物和上覆水为实验对象，研究了不同投加方式（混合和覆盖）下镁改性生物炭对上覆水中磷酸盐的吸附及对沉积磷的控制作用。生物炭混合和覆盖均可有效降低上覆水中溶解性无机磷（DIP）的浓度，与对照组相比，累积磷吸附量混合时提高了17.3%，覆盖时提高了11.7%。生物炭混合对沉积磷的控制效果更明显；与对照组相比，沉积水层0 - 2 cm至4 - 6 cm处的DIP分别降低了14.7%、18.9%和35.36%。生物炭覆盖时沉积水层的DIP分别降低了33.3%、-28.2%和12.9%。与对照组相比，0 - 2 cm和2 - 4 cm沉积物中NH₄Cl - P的比例混合时分别增加了15%和15%，覆盖时分别增加了12%和2%，而总磷（TP）中BD - P分别降低了7%和9%（混合）、6%和3%（覆盖），TP中Al - P分别降低了7%和6%（混合）、7%和-1%（覆盖）。其他磷形态变化不显著。生物炭混合和覆盖均可提高表层沉积物中的微生物活性，生物炭混合对较深层沉积物中微生物活性的提高更显著。
