针铁矿吸附多聚磷酸盐的研究：溶解有机质的影响

发布时间：2018-06-15 15:37

  本文选题：针铁矿 + 多聚磷酸盐　； 参考：《安徽建筑大学》2016年硕士论文

【摘要】：多聚磷酸盐是存在于自然环境中的无机磷形态的一种,排入到环境中的多聚磷酸盐在自然界中迁移转化,对水体富营养化和生物可利用性有一定的影响。针铁矿广泛存在于各种沉积物和土壤中,和自然界中污染性元素的迁移转化有着密切的关系,一直被研究者用来进行了多方面的研究。自然环境是复杂的,大部分地表环境中都能追踪到有机质的存在,其作为第三方添加物来研究各种污染物质的迁移转化机制已经得到越来越多的重视。为深入了解自然水体中多聚磷酸盐的迁移转化行为,选定焦磷酸盐和三聚磷酸盐作为代表性的多聚磷酸盐,以表生环境中广泛存在的稳定矿物-针铁矿为研究对象,系统研究了其对多聚磷酸根的吸附过程,探索了不同实验条件下(pH、电解质、时间、温度)针铁矿对多聚磷酸根吸附的影响。并通过不同添加顺序的腐殖酸(HA)和富理酸(FA)深入研究有机质-针铁矿-多聚磷酸盐三元体系的吸附行为:(1)通过研究有机质-针铁矿-焦磷酸根的体系发现,溶液pH值从6.27升至10.99时,总磷吸附量从3.00 mg/g降低至0.75 mg/g;电解质浓度越低越有利于针铁矿对焦磷酸根的吸附;吸附剂对焦磷酸根的吸附量在最初1 h内增长较快,随后渐渐达到吸附平衡;溶液温度的升高对吸附量提高具有增强作用。用动力学和热力学模型对吸附过程进行拟合,发现准二级动力学和Langmuir模型具有更好的适用性。针铁矿吸附焦磷酸根受HA影响吸附量大小变化为:Goe+PP,HA≈Goe+PP+HA≈HA+PP,GoeGoe+HA,PP。针铁矿吸附焦磷酸根受FA影响吸附量整体也呈促进趋势,吸附量大小变化为:Goe+PP,FA≈FA+PP,GoeGoe+PP+FAGoe+FA,PP。结合材料吸附焦磷酸根前后的表征,推导出针铁矿对焦磷酸根的吸附机制可能是以表面络合和物理吸附为主导。(2)通过研究有机质-针铁矿-三聚磷酸根的体系发现,溶液pH值从8.43升至10.97时,总磷吸附量从1.98 mg/g降低至0.27mg/g;电解质浓度越高越有利于针铁矿对三聚磷酸根的吸附;吸附剂对三聚磷酸根的吸附量在最初1 h内增长较快,随后渐渐达到吸附平衡;溶液温度的升高对吸附量提高具有增强作用。用动力学和热力学模型对吸附过程进行拟合,发现准二级动力学和Freundilich模型具有更好的适用性。针铁矿吸附三聚磷酸根受HA影响能抑制吸附量,吸附量大小变化为:Goe+TPP,HAGoe+TPP+HAHA+TPP,GoeGoe+HA,TPP。针铁矿吸附三聚磷酸根受FA影响吸附量整体也呈促进趋势,可能是因为在针铁矿表面形成了针铁矿-FA络合物。结合材料吸附三聚磷酸根前后的表征,推导出针铁矿对三聚磷酸根的吸附机制。
[Abstract]:Polyphosphate is a kind of inorganic phosphorus that exists in the natural environment. The polyphosphate discharged into the environment has a certain influence on the eutrophication and bioavailability of water body. Goethite exists widely in various sediments and soils and is closely related to the migration and transformation of polluting elements in nature. The natural environment is complex, most of the surface environment can trace the existence of organic matter, as a third party additive to study the mechanism of transport and transformation of various pollutants has been paid more and more attention. In order to understand the migration and transformation behavior of polyphosphate in natural water, pyrophosphate and tripolyphosphate were selected as representative polyphosphate, and goethite, a stable mineral widely existed in supergene environment, was chosen as the object of study. The adsorption process of polyphosphate was systematically studied, and the effects of pH, electrolyte, time and temperature on the adsorption of polyphosphate were investigated under different experimental conditions. The adsorption behavior of organic matter goethite polyphosphate ternary system was studied by means of humic acid (HA) and fulvic acid (FAA) in different order. The results showed that the adsorption behavior of organic matter goethite / polyphosphate ternary system was studied by studying the system of organic matter goethite and pyrophosphate. When pH value increased from 6.27 to 10.99, the total phosphorus adsorption decreased from 3.00 mg/g to 0.75 mg / g. The lower the electrolyte concentration was, the better the adsorption of pyrophosphate on goethite was. Then the adsorption equilibrium was gradually reached, and the increase of solution temperature enhanced the adsorption capacity. The kinetic and thermodynamic models were used to fit the adsorption process, and it was found that the quasi-second-order kinetic model and Langmuir model were more suitable. The adsorption capacity of goethite adsorbed pyrophosphate is changed from 1: Goe PPN HA 鈮，

本文编号：2022549