Gan Fangqun, Zhou Jianmin, Wang Huoyan, Du Changwen, Chen Xiaoqin
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, China; Graduate University of Chinese Academy of Sciences, 100049 Beijing, China.
Water Res. 2009 Jun;43(11):2907-15. doi: 10.1016/j.watres.2009.03.051. Epub 2009 Apr 14.
The potential of activated palygorskite was assessed for sorption of phosphate from aqueous solution. The natural palygorskite used was treated by thermal activation over 100-1000 degrees C for 2h. The thermal activation increased the phosphate sorption capacity and the highest phosphate sorption capacity occurred at 700 degrees C. H700 (palygorskite heated at 700 degrees C) showed higher sorption rate than natural palygorskite (NPAL), and the removal was favorable in acidic media. The sorption data were described using Freundlich isotherm equation over the concentration range (5-1000mg/L) (25 degrees C). Calcium bound phosphorus was the main fraction of the adsorbed phosphorus, about 98.0% in NPAL and 58.2% in H700, but the extractive Ca-P species varied greatly, Ca(2)-P was 87.7% in NPAL and 3.0% in H700, Ca(8)-P was 10.1% in NPAL and 54.5% in H700, and metal bound phosphorus was less than 2% in NPAL but more than 41.4% in H700, respectively. The dependence of the phosphate sorption capacity in the heating samples on thermal activation appears to be related to major changes in the crystal structure of palygorskite, and more calcium, iron and aluminum were released from the crystal matrix at 700 degrees C, which promoted phosphorus sorption.
评估了活化坡缕石从水溶液中吸附磷酸盐的潜力。所使用的天然坡缕石通过在100 - 1000摄氏度下热活化2小时进行处理。热活化提高了磷酸盐吸附容量，且最高磷酸盐吸附容量出现在700摄氏度。H700（在700摄氏度下加热的坡缕石）显示出比天然坡缕石（NPAL）更高的吸附速率，并且在酸性介质中去除效果良好。在浓度范围（5 - 1000mg/L）（25摄氏度）内，使用弗伦德利希等温方程描述吸附数据。钙结合磷是吸附磷的主要部分，在NPAL中约为98.0%，在H700中为58.2%，但可提取的钙磷物种差异很大，Ca(2)-P在NPAL中为87.7%，在H700中为3.0%，Ca(8)-P在NPAL中为10.1%，在H700中为54.5%，金属结合磷在NPAL中小于2%，但在H700中分别大于41.4%。加热样品中磷酸盐吸附容量对热活化的依赖性似乎与坡缕石晶体结构的主要变化有关，并且在700摄氏度时更多的钙、铁和铝从晶体基质中释放出来，这促进了磷的吸附。
