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Microwave-Enhanced Tea Saponin-Citric Acid Composite Leaching for Remediation of Heavy Metal-Contaminated Soil in Southern Yunnan Mining Areas

Xiaoyan Shang, Zhaojie Luo, Yingmei Li
Vol. 7, No. 12, pp. 103-115, 2025 DOI: 10.54691/43wszg35 December 20, 2025
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Abstract.This study investigates the removal efficiency of heavy metals (lead and copper) from heavily contaminated soils in the old mining area of southern Yunnan Province. Using microwave-enhanced composite leaching agents (tea saponin-citric acid), we conducted single-factor experiments to optimize parameters including microwave power, treatment duration, citric acid concentration, tea saponin concentration, and solid-to-liquid ratio. The optimal conditions were determined as follows: 539 W microwave power, 40-second treatment time, 0.60 mol/L citric acid concentration, 5% tea saponin concentration, and 1:25 solid-to-liquid ratio, achieving 46.86% lead removal and 40.49% copper removal. Subsequently, Plackett-Burman experiments were performed to identify factors significantly affecting lead and copper removal rates. The most efficient conditions for lead removal were 539 W microwave power, 38-second treatment time, 0.65 mol/L citric acid concentration, and 1:26 solid-to-liquid ratio, yielding 55.42% lead removal. For copper removal, the optimal conditions were 539 W microwave power, 34-second treatment time, 0.75 mol/L citric acid concentration, and 1:22 solid-to-liquid ratio, achieving 52.98% copper removal.
Keywords. Microwave Enhancement; Citric Acid; Tea Saponin; Soil Heavy Metal Pollution; Plackett-Burman Test.
APA Citation Xiaoyan Shang, Zhaojie Luo, Yingmei Li (2025). Microwave-Enhanced Tea Saponin-Citric Acid Composite Leaching for Remediation of Heavy Metal-Contaminated Soil in Southern Yunnan Mining Areas. Scientific Journal of Technology, 7(12), 103-115. https://doi.org/10.54691/43wszg35

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