Browsing by Author "Ihle, C."

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    Evaluation of sulfate rhizofiltration by Carpobrotus chilensis for treating mining waters
    (2024) Tapia, Y.; Salazar, O.; Joven, A.; Castillo, B.; Urdiales, C.; Garcia, A.; Ihle, C.; Acuna, E.
    Chile, the world's leading copper producer, generates significant volumes of mining waters, some of which cannot be recirculated into the production process. These mining waters are characterized by elevated sulfate (SO42-) concentrations, requiring sustainable management strategies for potential reuse. This study aims to evaluate the rhizofiltration technique using Carpobrotus chilensis for treating mining waters with a high SO(4)(2- )concentration. Initially, the mining waters exhibited a pH of 7.97 +/- 0.16 and a SO42- concentration of 2,743 +/- 137 mg L-1, while the control water had a pH of 7.88 +/- 0.08 and a SO42- concentration of 775 +/- 19.0 mg L-1. The plants were hydroponically cultivated in 40 L containers with mining waters and drinking water as a control. Over an 8-week period, the pH of the mining water decreased to 3.12 +/- 0.01, and the SO42- concentration declined to 2,200 +/- 110 mg L-1. Notably, the fresh weight of roots was significantly higher in plants grown in mining water (22.2 +/- 6.66 g) compared to those in the control treatment (14.3 +/- 4.28 g). However, an undesirable increase in the acidity was observed in the mining waters after rhizofiltration, which was attributed to hydrogen sulfate (HSO4-) and/or root exudates. Despite the unexpected increase in acidity, C. chilensis effectively reduced the concentration of SO42- in mining waters by 20%. Additionally, the C. chilensis roots accumulated 4.84 +/- 1.40% of sulfur (S), a level comparable to thiophore plants. This study provides evidence that this non-aquatic plant can be used in sulfate rhizofiltration. NOVELTY STATEMENT Caprobrotus chilensis is a good candidate for sulfate rhizolfiltration in mining waters. The accumulation of sulfur by the roots of Carpobrotus chilensis reached 4.84% Mining waters with a high concentration of sulfates require control of the redox potential