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Mathematical modeling of encapsulated buffer performance in controllingpH during remediation of groundwater.

机译：地下水修复过程中控制pH值的封装缓冲液性能的数学模型。

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摘要

Mathematical modeling was used to investigate the performance of encapsulated buffers (microcapsule and macrocapsule) in controlling pH during groundwater remediation process. This research work involves two one-dimensional, one two-dimensional convective/dispersive models coupling chemical/biological reactions to describe the transport and fate of chemical species, and one optimization model for parameter determination. A one-dimensional model was developed to simulate pH control using a micro-encapsulated buffer (KH 2PO4) in a soil column. After verification with experimental data from a denitrification process in a sand column, the model was applied to analyze the influence of different physical and chemical parameters on the performance of an encapsulated phosphate buffer for controlling pH and enhancing a pH-dependent process in a soil column. The parameters required for the model were based on the physical measurement. In the hypothetical scenarios for the general application study, the production of base equivalents is countered by the release of the acidic core of the encapsulated phosphate, resulting in an enhanced removal of the target compound.; To increase the efficiency of the encapsulated buffer, a new macrocapsule was developed. The release of encapsulated buffer core was assumed to follow first order kinetics with a pH-dependent coefficient involving four constants. The constants value was determined by experimental data fit using an optimization model based on simulated annealing. The optimization model satisfactorily fit and predicted the batch experimental data and provided the release kinetics of the macrocapsule for the further research. It was also found that the acidic polymer coat (Eudragit S 100) caused pH drop through both the modeling and experimental investigation.; Based on the characteristics investigation of encapsulated buffer in batch and flow-through scenarios, the one-dimensional transport model was extended to two-dimensions simulating a horizontal domain for the practical engineering objectives of improving pH condition and increasing the removal efficiency of contaminants. The physical and chemical parameters for the base case study (e.g. influent concentration of species, pH) in the two-dimensional situation were based on the sensitivity analysis results from those parameters used in the column study. The two-dimensional modeling investigation provides a theoretical base for the application of the macrocapsules in engineering.
机译：使用数学模型研究了胶囊修复的缓冲液（微囊和大囊）在地下水修复过程中控制pH的性能。这项研究工作涉及两个一维，一个二维对流/扩散模型，它们结合化学/生物反应来描述化学物质的迁移和命运，以及一个用于确定参数的优化模型。开发了一个一维模型来模拟在土壤柱中使用微囊化缓冲液（KH 2PO4）进行的pH控制。在用砂柱中的反硝化过程的实验数据进行验证后，该模型被用于分析不同物理和化学参数对封装的磷酸盐缓冲液性能的影响，该缓冲液用于控制pH和增强土壤柱中的pH依赖性过程。模型所需的参数基于物理测量。在一般应用研究的假想场景中，碱当量的产生被包封的磷酸盐的酸性核的释放所抵消，从而提高了目标化合物的去除率。为了提高封装缓冲液的效率，开发了一种新的大胶囊。假定包封缓冲核的释放遵循一级动力学，其pH依赖性系数涉及四个常数。使用基于模拟退火的优化模型通过实验数据拟合确定常数值。该优化模型令人满意地拟合并预测了批量实验数据，并为进一步研究提供了大胶囊的释放动力学。还通过建模和实验研究发现，酸性聚合物涂层（Eudragit S 100）导致pH下降。基于批量和流通情况下封装缓冲液的特性研究，将一维传输模型扩展到二维模拟水平域，以实现改善pH条件和提高污染物去除效率的实际工程目标。在二维情况下，基础案例研究的物理和化学参数（例如物种的进水浓度，pH）是基于专栏研究中使用的那些参数的敏感性分析结果得出的。二维建模研究为大胶囊在工程中的应用提供了理论基础。

著录项

  • 作者

    Liu, Lubo.;

  • 作者单位

    University of South Carolina.;

  • 授予单位 University of South Carolina.;
  • 学科 Environmental Sciences.; Geochemistry.; Engineering Environmental.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 211 p.
  • 总页数 211
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境科学基础理论;地质学;环境污染及其防治;
  • 关键词

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