Effect of phosphate on the reduction of U(VI) on nZVI was determined by batch, XPS, XANES and EXAFS techniques. The batch experiments showed that nZVI was quite effective for the removal of uranium under the anaerobic conditions, whereas the addition of phosphate enhanced uranium removal over wide pH range. At low pH, the reduction of U(VI) to U(IV) significantly decreased with increasing phosphate concentration by XPS and XANES analysis. According to EXAFS analysis, the occurrence of U

U shell at 10 mg/L phosphate and pH 4.0 was similar to that of U^(IV)O₂(s), whereas the UP and UFe shells were observed at 50 mg/L phosphate, revealing that reductive co-precipitate (U^(IV)O₂(s)) and precipitation of uranyl-phosphate were observed at low and high phosphate, respectively. The findings are crucial for the prediction of the effect of phosphate on the speciation and binding of uranium by nZVI at low pH, which is significant in controlling the mobility of U(VI) in contaminated environments.

中文翻译：

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XANES和EXAFS在磷酸盐存在下对nZVI中铀掺入的研究

通过分批，XPS，XANES和EXAFS技术确定磷酸盐对nZVI上U（VI）还原的影响。批处理实验表明，nZVI在厌氧条件下对铀的去除非常有效，而磷酸盐的添加则在较宽的pH范围内提高了铀的去除率。在低pH值下，通过XPS和XANES分析，随着磷酸盐浓度的增加，U（VI）还原为U（IV）的幅度显着降低。根据EXAFS分析，U的发生

在10 mg / L磷酸盐和pH 4.0下的U壳与U ^（IV） O ₂（s）相似，而UP和U在50 mg / L磷酸盐下观察到铁壳，表明在低磷酸盐和高磷酸盐下分别观察到还原性共沉淀物（U ^（IV） O ₂（s））和铀酰磷酸盐的沉淀。这些发现对于预测磷酸盐在低pH下对nZVI对铀的形态和结合的影响至关重要，这对于控制受污染环境中U（VI）的迁移性具有重要意义。