The catalysts derived from natural iron minerals in the advanced oxidation process offer several advantages. However, their utilization in soil remediation is restricted due to the presence of soil impurities, which can inhibit the catalytic activity of these minerals. The soils in tropical regions exhibit lower organic matter content, limited cation exchange capacity, and are non-saline, this enhances the efficiency of utilizing natural iron minerals from tropical soil as a catalyst. In this regard, the catalytic potential of naturally iron-bearing tropical soil was investigated to eliminate phenanthrene (PHE), pyrene (PYR), and benzo[α]pyrene (B[α]P) using an oxygenated reactor supported with persulfate (PS). The system showed an efficient performance, and the removal efficiencies under the optimum conditions were 81 %, 73 %, and 86 % for PHE, PYR, and B[α]P, respectively. This indicated that the catalytic activity of iron was working efficiently. However, there were changes in the soil characteristics after the remediation process such as a significant reduction in iron and aluminum contents. The scavenging experiments demonstrated that had a minor role in the oxidation process, and emerged as the primary reactive species responsible for the effective degradation of the PAHs. Moreover, the by-products were monitored after soil remediation to evaluate their toxicity and to propose degradation pathways. The Mutagenicity test showed that two by-products from each PHE and B[α]P had positive results, while only one by-product of PYR showed positive. The toxicity tests of oral rat LD and developmental toxicity tests revealed that certain PAHs by-products could be more toxic from the parent pollutant itself. This study represents a notable progression in soil remediation by providing a step forward in the application of the advanced oxidation process (AOP) without requiring additional catalysts to activate oxidants and degrade pollutant PAHs from the soil.

中文翻译：

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热带土壤中多环芳烃的高级氧化：过硫酸盐支持的氧化反应器中天然铁含量的自催化利用

在高级氧化过程中，源自天然铁矿物的催化剂具有多种优势。然而，由于土壤杂质的存在会抑制这些矿物质的催化活性，因此它们在土壤修复中的应用受到限制。热带地区的土壤有机质含量较低，阳离子交换能力有限，并且是非盐分的，这提高了利用热带土壤中的天然铁矿物质作为催化剂的效率。在这方面，使用过硫酸盐（PS）支持的氧化反应器研究了天然含铁热带土壤的催化潜力，以消除菲（PHE）、芘（PYR）和苯并[α]芘（B[α]P） ）。该系统表现出高效的性能，在最佳条件下对PHE、PYR和B[α]P的去除效率分别为81%、73%和86%。这表明铁的催化活性正在有效发挥作用。然而，修复过程后土壤特性发生了变化，例如铁和铝含量显着降低。清除实验表明，它在氧化过程中作用较小，并成为有效降解多环芳烃的主要活性物质。此外，在土壤修复后对副产物进行监测，以评估其毒性并提出降解途径。致突变性测试显示，PHE 和 B[α]P 各有 2 个副产物呈阳性，而 PYR 只有 1 个副产物呈阳性。大鼠口服 LD 的毒性测试和发育毒性测试表明，某些 PAH 副产物的母体污染物本身的毒性可能更大。这项研究代表了土壤修复领域的显着进展，在高级氧化工艺 (AOP) 的应用方面向前迈进了一步，无需额外的催化剂即可激活氧化剂并降解土壤中的污染物多环芳烃。