Modeling speciation effects on biodegradation in mixed metal/chelate systems
Modeling speciation effects on biodegradation in mixed metal/chelate systems
复制标题
模拟混合金属/螯合物系统中生物降解的形态效应
作者：
J. Vanbriesen;B. Rittmann
新模型 CCBATCH 将微生物催化反应与水体地球化学全面耦合。 CCBATCH 中明确包含水体形态对生物降解反应的影响以及生物反应对化学物质（例如 H2CO3、NH4+、O2）浓度的影响，从而可以对动力学控制的生物反应进行系统研究。包括酸/碱和络合在内的体相化学形态反应被建模为热力学控制，而生物反应被建模为动力学控制。生物降解反应的双 Monod 动力学公式与降解反应的化学计量相结合，以预测受生物反应影响的所有生物和化学物质的变化率。 CCBATCH 捕获 pH 值和形态对生物反应的影响的能力通过柠檬酸盐/Fe(III) 系统的一系列建模示例得到证明。 pH 控制潜在的生物利用形式柠檬酸盐的浓度。当可降解底物的百分比由于络合或酸/碱形态而较低时，尽管底物浓度较高，但降解速率可能很慢。以不可降解形式螯合底物的络合反应可以在底物完全利用之前防止降解或停止降解反应。 CCBATCH 将水体形态变化与生物降解反应动力学和化学计量耦合的能力允许预测混合金属/螯合物系统中的这些关键行为。
A new model, CCBATCH, comprehensively couples microbially catalyzed reactions to aqueous geochemistry. The effect of aqueous speciation on biodegradation reactions and the effect of biological reactions on the concentration of chemical species (e.g. H2CO3, NH4+, O2) are explicitly included in CCBATCH, allowing systematic investigation of kinetically controlled biological reactions. Bulk-phase chemical speciation reactions including acid/base and complexation are modeled as thermodynamically controlled, while biological reactions are modeled as kinetically controlled. A dual-Monod kinetic formulation for biological degradation reactions is coupled with stoichiometry for the degradation reaction to predict the rate of change of all biological and chemical species affected by the biological reactions. The capability of CCBATCH to capture pH and speciation effects on biological reactions is demonstrated by a series of modeling examples for the citrate/Fe(III) system. pH controls the concentration of potentially biologically available forms of citrate. When the percentage of the degradable substrate is low due to complexation or acid/base speciation, degradation rates may be slow despite high concentrations of substrate Complexation reactions that sequester substratein non-degradable forms may prevent degradation or stopdegradation reactions prior to complete substrate utilization. The capability of CCBATCH to couple aqueous speciation changes to biodegradation reaction kinetics and stoichiometry allows prediction of these key behaviors in mixed metal/chelate systems.