降尘与人工粉尘在谷氨酸中的溶解特性

A Study on Dissolution of Natural, Artificial and Industrial Dusts with Glutamic Acid

针对自然降尘、工业区降尘及人工粉尘进行的物相、成分、表面形貌、元素含量和粒度分析表明降尘均以石英和方解石为主要物相成分,SiO2、CaO含量较高,K2O、Na2O含量低。自然降尘为无规则颗粒,大颗粒表面上带有微小颗粒团聚;工业区降尘形貌呈球形、团状;人工粉尘呈柱状或纤维状。降尘粒度在0.3~5μm内集中分布,小于5μm的粉尘比例均超过99%。在模拟人体温度37℃条件下,进行了32 h内粉尘在谷氨酸水溶液中的溶出行为和电化学作用的对比研究。各粉尘样品的pH值和电导率变化趋势相似,8 h前各粉尘样品的pH值电导率随时间增加缓慢上升,8 h到32 h间pH值上升速度明显加快。元素K、Ca、Na、Mg的溶出离子总量为35.4~429 mg/L,其中Ca元素的溶出量最大为20~334 mg/L,重金属离子Fe、Zn、Mn、Pb、Ba的离子溶出总量为0.18~5.59 mg/L,Al、Si离子溶出总量为3.0~21.7 mg/L。粉尘中各元素主要在前16 h溶出较快。各粉尘在酸性谷氨酸水溶液中的溶解程度由大到小为:硅灰石】蛇纹石】海泡石;水泥厂降尘】自然降尘】电厂降尘。CaO含量高的水泥厂降尘和硅灰石人工粉尘溶解程度最大,表明其在酸性谷氨酸环境中耐腐蚀性较差,表现出较低的生物持久性。SiO2含量高的电厂降尘和海泡石人工粉尘溶解程度最小,具有较强耐蚀能力和较高生物持久性。

This article describes the characteristics of natural, artificial and industrial dusts, such as mineral phases, their chemical components, morphological observations and size. Quartz and calcite are the main phases in natural and industrial dusts with high SiO2 and CaO and low K2O and Na2O in chemical composition. Natural dusts consist mainly of irregular shapes particulates, with some aggregated particles made of smaller dusts on the surface of larger dust particles. Industrial dusts are more sphericular, while artificial dusts are columnar and fibrous. The particles mainly range 0.3 to 5 μm in size, with over 99% smaller than 5 μm. Under the condition of a simulated human body temperature(37 ℃), the dissolution and electrochemical behaviour of dust in aqueous glutamic acid were being investigated for 32 hours. Changes of the pH values and conductivity for all types of dust were similar, increasing slowly in the first 8 hours, then the pH values increased rapidly. The total amount of dissolved K, Ca, Na and Mg ions were in the range of 35.4 to 429 mg/L – particularly Ca, which has a maximum range of 20 to 334 mg/L. The total amount of dissolved Fe, Zn, Mn, Pb and Ba ions were in the range of 0.18 to 5.59 mg/L, while Al and Si were within 3.0 to 21.7 mg/L range. Each element dissolved relatively rapidly in the first 16 hours. The order of relative solubility of the various types of dust examined with glutamic acid is: wollastonite>serpentine> sepiolite; cement plant industrial dust>natural dust>power plant industrial dust. Wollastonite dust and power plant industrial dust have the highest solubility(with high content of CaO) and display poorer corrosion-resistance and lower bio- resistance. Sepiolite and cement plant industrial dust have the lowest degree of solubility(with high contents of SiO2) and display higher corrosion- resistance and stronger bio- resistance.