透水性沥青路面对路面径流中重金属的控制机理研究

发布时间：2018-05-30 13:07

本文选题：透水性沥青路面 + 路面径流　；参考：《南京林业大学》2014年博士论文

【摘要】：将透水性沥青路面用于控制路面径流重金属污染是透水性沥青路面技术的重要发展方向之一。而我国在透水性沥青路面对路面径流中重金属的控制效果及其机理研究尚少,缺乏必要的数据支撑。因此,本文主要从雨水入渗路径及路面材料和结构的角度出发,基于透水性沥青路面对路面径流重金属污染的控制效果及行为规律,深入研究透水性沥青路面对路面径流中重金属的控制机理。论文首先分析了透水性沥青路面的透水过程,建立了透水性沥青路面的渗透-蓄水计算模型,得到基于有效控制路面地表径流的透水性沥青混合料目标空隙率的计算表达式和路面结构透水效能的评价方法。其次,根据得到的目标空隙率,进行了透水性沥青混合料配合比设计研究,并进行其性能验证；从有效控制地表径流的角度研究了透水性沥青路面断面型式,同时分析了典型结构型式在不同降雨历时、不同设计重现期下的透水效能。第三,通过室内人工模拟降雨试验,研究了透水性沥青路面典型结构型式对路面径流中Pb、Zn的控制效果,并基于蓄水层集料性质深入探讨了其控制机理。最后,通过静态模拟浸泡法研究了孔隙壁沥青对路面径流中溶解态Pb、Zn的吸附性能；对吸附试验前后沥青薄膜样品表面进行X射线光电子能谱分析；对试验数据进行吸附热力学和吸附动力学的研究,并基于沥青的化学特性,深入探讨了孔隙壁沥青对路面径流中Pb2+、Zn2+的吸附机理。通过上述研究,本文主要得到以下研究结论： (1)通过分析降雨条件下透水性沥青路面的渗透和产流机制,基于水量平衡原理建立了透水性沥青路面的渗透-蓄水计算模型,得到基于有效控制地表径流的透水性沥青混合料目标空隙率的计算表达式,以及透水性沥青路面透水效能的评价方法。 (2)透水性沥青路面对路面初期冲刷径流中Pb、Zn具有显著的控制效果；但其在蓄水阶段对Pb、Zn的控制作用具有显著的差异性：对Pb始终保持较高的去除率,对Zn的去除率表现为先负后正。 (3)透水性沥青路面对初期冲刷径流中Pb、Zn的控制作用主要依靠路面内部微观空隙结构的物理截留以及颗粒物的吸附作用；蓄水阶段对路面径流中Pb、Zn的控制作用与蓄水层集料性质及蓄水时间有关。石灰岩集料对Pb2+、Zn2+的控制机理为：以“重金属碳酸盐沉淀络合物”或以Pb(OH)2和Zn(OH)2沉淀的形式吸附在集料表面；玄武岩集料对Pb2+、Zn2+的控制机理为：分别以Pb(OH)2和Zn(OH)2沉淀的形式吸附在集料表面。 (4)吸附前后沥青薄膜表面的X射线光电子能谱分析证明沥青薄膜样品表面新增的Pb、Zn来源于其自溶液中对Pb2+、Zn2+的吸附。 (5)沥青中不同组分对沥青薄膜自溶液中吸附Pb2+、Zn2+有着重要影响：一是沥青中一些极性组分的水解和电离,增加了溶液中氢离子和羧酸根离子；二是羧酸根离子与溶液中Pb2+、Zn2+反应生成固态高价有机盐沉淀,增加沥青薄膜对Pb2+、Zn2+的吸附量；三是亚砜类O‖(R-S-R*)通过配位键的方式与重金属离子生成配位络合物或溶剂化物,增加沥青薄膜对Pb2+、Zn2+的吸附量,但同时亚砜类也会与水发生化学反应,阻碍沥青薄膜对Pb2+、Zn2+的吸附；四是溶液中的氢离子与固态高价有机盐反应,置换出其中的重金属离子,生成新的沥青酸,从而降低沥青薄膜对Pb2+、Zn2+的吸附量。 (6)对于Pb2+、Zn2+,在给定吸附剂投加量、保持较高初始浓度的条件下,快速吸附阶段可用抛物线扩散方程描述；重金属离子初始浓度较低时，可用双常数速率方程和Elovich方程描述。且在具体条件下，整个吸附过程符合准二级动力学方程规律。（7）吸附等温线研究结果表明，在给定吸附剂投加量、改变重金属离子初始浓度时，，沥青薄膜对Pb2+、Zn2+的吸附用Freundlich吸附等温模型描述较为合适。
[Abstract]:The use of permeable asphalt pavement to control heavy metal pollution of pavement runoff is one of the important development directions of permeable asphalt pavement technology. However, there are few studies on the control effect and mechanism of heavy metals in water permeable asphalt pavement in China, and lack of necessary data support. This paper mainly from the rain infiltration path and road surface. On the basis of material and structure angle, based on the control effect and behavior law of heavy metal pollution of pavement runoff, the control mechanism of heavy metal in surface runoff of permeable asphalt road is studied in depth.
The paper first analyzes the permeable process of the permeable asphalt pavement, and establishes the seepage and storage calculation model of the permeable asphalt pavement, and obtains the calculation expression of the target void ratio of the permeable asphalt mixture based on the effective control of the surface runoff of the pavement and the evaluation method of the permeability efficiency of the pavement structure. Secondly, according to the target void ratio obtained. The mixture ratio design of permeable asphalt mixture is carried out and its performance is verified. From the angle of effective control of surface runoff, the broken face type of permeable asphalt pavement is studied. At the same time, the water penetration efficiency of typical structural types in different rainfall periods and different design reappearance periods is analyzed. Third, artificial simulation of rainfall through indoor simulation is carried out. The control effect of the typical structural type of permeable asphalt pavement on Pb and Zn in surface runoff was studied. Based on the properties of the reservoir aggregate, the control mechanism was deeply discussed. Finally, the adsorption performance of the dissolved Pb and Zn in the surface runoff by the pore wall asphalt was studied by the static simulation soaking method; and the asphalt film samples before and after the adsorption test were studied. The surface is analyzed by X ray photoelectron spectroscopy, and the adsorption thermodynamics and adsorption kinetics of the experimental data are studied. Based on the chemical properties of asphalt, the adsorption mechanism of Pb2+ and Zn2+ in pavement runoff by pore wall bitumen is discussed in depth.
Through the above research, the following conclusions can be drawn:
(1) through the analysis of the permeability and flow mechanism of the permeable asphalt pavement under the rainfall condition, based on the principle of water balance, the seepage and storage calculation model of the permeable asphalt pavement is established, and the calculation expression of the porosity of the asphalt mixture based on the effective control of the surface runoff and the permeability of the permeable asphalt pavement are obtained. Evaluation method.
(2) the water permeable asphalt road has significant control effect on the Pb in the initial scour runoff in the pavement, but its control effect on the Pb and Zn in the water storage stage has significant difference. The high removal rate of Pb is maintained and the removal rate of Zn is first negative and positive.
(3) the control effect of Zn is mainly dependent on the physical intercepting of the micro gap structure inside the pavement and the adsorption of particles, and the control effect of Pb and Zn in the water storage stage is related to the properties of the aggregate and the storage time. The control mechanism of the limestone aggregate for Pb2+ and Zn2+ is the mechanism of the control of Pb2+ and Zn2+. It is adsorbed on the aggregate surface in the form of "heavy metal carbonate precipitation complex" or Pb (OH) 2 and Zn (OH) 2 precipitation; the control mechanism of basalt aggregates for Pb2+ and Zn2+ is to adsorb on the aggregate surface in the form of Pb (OH) 2 and Zn (OH) 2) respectively.
(4) the X ray photoelectron spectroscopy analysis of the surface of the bitumen film before and after adsorption proves that the Pb of the surface of the film is added, and Zn is derived from the adsorption of Pb2+ and Zn2+ from the solution from the solution.
(5) the different components of bitumen have an important effect on the adsorption of Pb2+ in the solution of asphalt film from the solution, Zn2+ has an important effect: one is the hydrolysis and ionization of some polar components in the bitumen, the hydrogen ions and carboxate ions in the solution are increased, and the two is the reaction of carboxyacid root ions and Pb2+ in the solution to produce a solid high price organic salt precipitation, and the asphalt film is increased to Pb2+, Zn2+ The amount of adsorption is three. The three is that the sulfoxide class (R-S-R*) generates coordination complex or solvation with heavy metal ions through the coordination bond, increasing the adsorption amount of the asphalt film to Pb2+ and Zn2+, but at the same time, the sulfoxide will also react with water to prevent the adsorption of Pb2+ and Zn2+ from the bitumen film, and the four is the high price of hydrogen ion and solid in the solution. The organic salts react to replace the heavy metal ions to form new asphaltic acids, thereby reducing the adsorption capacity of asphalt film to Pb2+ and Zn2+.
(6) for Pb2+, Zn2+, the fast adsorption stage can be described by parabolic diffusion equation under the condition of a given dosage of a given adsorbent and high initial concentration. When the initial concentration of heavy metal ions is low, the two constant rate equation and the Elovich equation can be described. And the whole adsorption process is in accordance with the quasi two order kinetic equation under the specific strip. Law.
(7) the adsorption isotherm results show that the Freundlich adsorption isotherm model is more suitable for Pb2+ and Zn2+ adsorption when the amount of adsorbents is added and the initial concentration of heavy metal ions is changed.
【学位授予单位】：南京林业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U416.217

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