State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, 210008 Nanjing, China.
Water Res. 2013 Sep 1;47(13):4247-58. doi: 10.1016/j.watres.2013.04.044. Epub 2013 May 4.
Phosphorus from wastewaters and sediment flux to surface water represents a major source of lake eutrophication. Active filtration and in situ capping (which refers to placement of a covering or cap over an in-situ deposit of contaminated sediment) are widely used as a means to immobilize phosphorus from wastewaters and sediment, to mitigate lake eutrophication. There is, however, a need to develop more efficient means of immobilizing phosphorus through the development of binding agents. In this study, natural calcium-rich sepiolite (NCSP) was calcined at a range of temperatures, to enhance its phosphorus removal capacity. Batch studies showed that the 900 °C calcinated NCSP (NCSP900) exhibited excellent sorption performance, attaining a phosphorus removal efficiency of 80.0%-99.9% in the range of 0.05 mg/L-800 mg/L phosphorus concentrations with a dosage of 20 g/L. The material displayed rapid sorption rate (maximum amount of 99.9% of phosphate removal with 5 min) and could lower the very high phosphate concentration (200 mg/L) to less than 0.1 mg/L after 4 h adsorption. It was also noted that factors such as pH, competing anions (except [Formula: see text] ) and humic acid, had no effect on phosphorus removal capacity. The sediment immobilization experiment indicated that NCSP900 had the capacity to transform reactive phosphorus into inert-phosphorus and significantly reduce the amount of algal-bioavailable phosphorus. The excellent phosphorus binding performance of NCSP900 was mainly due to the improvement of point of zero charge (pHPZC) as well as the transformation of the inert-calcium of NCSP to active free CaO during calcination. Phosphorus speciation indicated that phosphorus was mainly captured by relatively stable calcium-bound phosphorus (Ca-P) precipitation, which can account for 80.1% of the total phosphorus. This study showed that NCSP900 could be used as an efficient binding agent for the sequestration of phosphorus from wastewaters and sediment.
污水和沉积物中的磷向地表水迁移是湖泊富营养化的主要来源之一。活性过滤和原位覆盖（即在原位受污染沉积物上覆盖或加盖）被广泛用作固定废水中和沉积物中的磷的方法，以减轻湖泊富营养化。然而，需要通过开发结合剂来开发更有效的固定磷的方法。在这项研究中，天然富钙海泡石（NCSP）在一系列温度下煅烧，以提高其除磷能力。批量研究表明，在 0.05mg/L-800mg/L 磷浓度范围内，900°C 煅烧的 NCSP（NCSP900）具有出色的吸附性能，当剂量为 20g/L 时，磷去除效率为 80.0%-99.9%。该材料具有快速的吸附速率（在 5 分钟内最大去除 99.9%的磷酸盐），并能在 4 小时吸附后将非常高的磷浓度（200mg/L）降低到低于 0.1mg/L。还注意到，pH 值、竞争阴离子（除 [Formula: see text] 外）和腐殖酸等因素对磷去除能力没有影响。沉积物固定化实验表明，NCSP900 能够将活性磷转化为惰性磷，并显著减少藻类可利用磷的含量。NCSP900 优异的磷结合性能主要归因于零电荷点（pHpZC）的提高以及 NCSP 中惰性钙在煅烧过程中向活性游离 CaO 的转化。磷形态分析表明，磷主要通过相对稳定的钙结合磷（Ca-P）沉淀捕获，这可占总磷的 80.1%。这项研究表明，NCSP900 可用作从废水中和沉积物中固定磷的有效结合剂。
