Yang Mengjuan, Lin Jianwei, Zhan Yanhui, Zhu Zhiliang, Zhang Honghua
College of Marine Science, Shanghai Ocean University, No. 999 Hucheng Huan Road, , Pudong District, 201306, Shanghai, China.
Environ Sci Pollut Res Int. 2015 Mar;22(5):3606-19. doi: 10.1007/s11356-014-3604-2. Epub 2014 Sep 26.
Adding sorbents to sediments has been suggested as an effective technology for contaminated sediment remediation. In this study, a zirconium-modified zeolite (ZrMZ) was prepared, characterized, and used as a sediment amendment to control phosphorus (P) release from eutrophic lake sediments. The efficiency of ZrMZ in immobilizing P from water and sediments was investigated through a series of experiments. The phosphate adsorption capacity for ZrMZ decreased with increasing water pH. The adsorption of phosphate on ZrMZ followed a pseudo-second-order kinetic model. The equilibrium adsorption data of phosphate on ZrMZ could be well described by the Langmuir isotherm model with a maximum monolayer adsorption capacity of 10.2 mg P/g at pH 7 and 25 °C. Sequential extraction of P from the phosphate-adsorbed ZrMZ suggested that most of P bound by ZrMZ existed as the NaOH extractable P (NaOH-P) and residual P (Res-P) and was unlikely to be released under natural pH and reducing conditions. The addition of ZrMZ into sediments reduced the inorganic P activity in the sediments by transforming bicarbonate-dithionite extractable P (BD-P) to NaOH-P and Res-P. The contents of bioavailable P such as water-soluble P (WS-P), NaHCO3 extractable P (Olsen-P), and algal available P (AAP) in sediments reduced after the sediments were mixed with ZrMZ, making P in the sediments more stable. The addition of ZrMZ into sediments significantly reduced the releasing flux of P from the sediments to the water column under different conditions. Results of this study indicate that the ZrMZ is a promising sediment amendment for controlling the internal P loading of lake sediments.
向沉积物中添加吸附剂已被认为是一种有效的污染沉积物修复技术。在本研究中，制备并表征了一种锆改性沸石（ZrMZ），并将其用作沉积物改良剂以控制富营养化湖泊沉积物中磷（P）的释放。通过一系列实验研究了ZrMZ对水中和沉积物中磷的固定效率。ZrMZ对磷酸盐的吸附容量随水的pH值升高而降低。磷酸盐在ZrMZ上的吸附遵循准二级动力学模型。磷酸盐在ZrMZ上的平衡吸附数据可以用Langmuir等温线模型很好地描述，在pH值为7和25℃时，最大单层吸附容量为10.2 mg P/g。对吸附磷酸盐的ZrMZ进行磷的连续提取表明，ZrMZ结合吸附的大部分磷以氢氧化钠可提取磷（NaOH-P）和残余磷（Res-P）的形式存在，在自然pH值和还原条件下不太可能释放。向沉积物中添加ZrMZ通过将碳酸氢盐-连二亚硫酸盐可提取磷（BD-P）转化为NaOH-P和Res-P，降低了沉积物中无机磷的活性。沉积物与ZrMZ混合后，沉积物中水溶性磷（WS-P）、碳酸氢钠可提取磷（Olsen-P）和藻类可利用磷（AAP）等生物可利用磷的含量降低，使沉积物中的磷更稳定。在不同条件下，向沉积物中添加ZrMZ显著降低了沉积物向水柱中磷的释放通量。本研究结果表明，ZrMZ是一种很有前景的沉积物改良剂，可用于控制湖泊沉积物的内源磷负荷。
