Di-(2-ethylhexyl) phthalate (DEHP) is a highly toxic and persistent contaminant. Elimination of DEHP from the environment is crucial to safe guard ecological and human health. Red seaweed-derived biochar (RSB), made from Agardhiella subulata residues, was used to activate sodium percarbonate (SPC) for the degradation of DEHP in contaminated estuarine surface sediments. The RSB was characterized by scanning transmission electron microscope-energy dispersive X-ray spectroscopy (STEM-EDS), micro-attenuated total reflectance-Fourier transform infrared spectroscopy (MATR-FTIR), elemental analysis (EA), thermogravimetric analysis (TGA), X-ray photoelectron spectrometry (XPS), linear sweep voltammetry (LSV), and Tafel measurements. Results revealed that the increase in SPC dosage, specifically, [DEHP] to [SPC] molar ratio of 1:1000, increased DEHP removal in the sediment. The pyrolysis temperature (300–900 °C) for biochar preparation significantly controlled the particle size and catalytic capacity of RSB. Pristine RSB contributed catalytic sites, which effectively activated SPC via electron transfer through the RSB matrix, that generated HO• and facilitated the carbocatalysis degradation of DEHP. RSB900 was the best-performing SPC activator. Under the optimal initial pH of 9, total DEHP degradation was 63% in 12 h. Treatment with RSB and SPC, significantly increased the bacterial abundance in the sediment. Results of next-generation sequencing analyses showed that Proteobacteria and Bacterioidetes were the dominant bacterial phyla. The microbial abundance and diversity of the sediment ecosystems were improved significantly upon treatment by the RSB–SPC process, indicating the efficacy of the remediation technology. Results provide valuable insights into the role of microbial communities as indicators of sediment quality.

邻苯二甲酸二（2-乙基己基）酯（DEHP）是一种剧毒且持久的污染物。从环境中消除DEHP对安全保护生态和人类健康至关重要。红海藻生物炭（RSB），由Agardhiella subulata制成残留物用于活化过碳酸钠（SPC），以降解受污染的河口表层沉积物中的DEHP。RSB的特征在于扫描透射电子显微镜-能量色散X射线光谱（STEM-EDS），微衰减全反射-傅立叶变换红外光谱（MATR-FTIR），元素分析（EA），热重分析（TGA）， X射线光电子能谱（XPS），线性扫描伏安法（LSV）和Tafel测量。结果表明，SPC剂量的增加，特别是[DEHP]与[SPC]摩尔比为1：1000，增加了沉积物中DEHP的去除。生物炭制备的热解温度（300–900°C）显着控制了RSB的粒径和催化能力。原始的RSB有助于催化位点，通过电子通过RSB基质有效激活SPC，产生HO•并促进DEHP的碳催化降解。RSB900是性能最佳的SPC活化剂。在最佳初始pH为9的情况下，12小时内DEHP的总降解率为63％。用RSB和SPC处理可显着增加沉积物中细菌的丰度。下一代测序分析结果表明细菌杆菌和细菌杆菌是主要的细菌门。通过RSB–SPC工艺处理后，沉积物生态系统的微生物丰度和多样性得到了显着改善，表明了修复技术的有效性。结果为微生物群落作为沉积物质量指标的作用提供了宝贵的见解。