Abstract. Understanding phenolic pollutants interaction with soil colloids has been a focus of extensive research, primarily under controlled conditions. This study addresses the need to explore these processes in a more natural, complex soil environment. We aim to enlighten the underlying mechanisms of hydroquinone (a representative phenolic pollutant) oxidation in ambient, MnO₂-rich sandy soil within soil columns designed for breakthrough experiments. Our innovative approach combines noninvasive electrical measurements, crystallographic and microscopic analyses, and chemical profiling to comprehensively understand soil-pollutant interactions. Our study reveals that hydroquinone oxidation by MnO₂ initiates a cascade of reactions, altering local pH, calcite dissolution, and precipitating amorphous Mn-oxides, showcasing a complex interplay of chemical processes. Our analysis, combining insights from chemistry and electrical measurements, reveals the oxidation process led to a constant decrease in polarizing surfaces, as indicated by quadrature conductivity monitoring. Furthermore, dynamic shifts in the soil solution chemistry (changes in the calcium and manganese concentrations, pH, and EC) correlated with the non-monotonous behavior of the in-phase conductivity. Our findings conclusively demonstrate that the noninvasive electrical method allows real-time monitoring of calcite dissolution, serving as a direct cursor to the oxidation process of hydroquinone, enabling the observation of soil surface processes, and chemical interactions.

中文翻译：

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土壤中锰氧化物的有机污染物氧化——地电和化学分析表明方解石的作用


摘要。了解酚类污染物与土壤胶体的相互作用一直是广泛研究的焦点，主要是在受控条件下。这项研究解决了在更自然、更复杂的土壤环境中探索这些过程的需要。我们的目标是揭示为突破性实验而设计的土柱内富含 MnO ₂的沙质土壤中对苯二酚（一种代表性酚类污染物）氧化的潜在机制。我们的创新方法结合了无创电测量、晶体学和显微分析以及化学分析，以全面了解土壤与污染物的相互作用。我们的研究表明，MnO ₂氧化氢醌会引发一系列反应，改变局部 pH 值、方解石溶解并沉淀无定形锰氧化物，展示了化学过程的复杂相互作用。我们的分析结合了化学和电气测量的见解，揭示了氧化过程导致极化表面不断减少，如正交电导率监测所示。此外，土壤溶液化学的动态变化（钙和锰浓度、pH 值和 EC 的变化）与同相电导率的非单调行为相关。我们的研究结果最终证明，非侵入性电方法可以实时监测方解石溶解，作为对苯二酚氧化过程的直接指标，从而能够观察土壤表面过程和化学相互作用。