Effective Treatment of Mining Wastewater with Biochar-Based Persulfate System Across Variable pH Conditions

Researchers developed a potassium chloride-activated biochar and persulfate (KBBC/PS) system to treat flotation reagent-contaminated mining wastewater across varying pH levels. The study demonstrated efficient pollutant degradation through different reactive species and confirmed the system’s practical applicability in continuous flow experiments.

May 27, 2024

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Yang, et al (2024) Reactive species identification in KCl activated biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More/persulfate system under different pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More condition: Theoretical calculation and column experiments. *Chemical Engineering Journal.* https://doi.org/10.1016/j.cej.2024.151983

Researchers have tackled the issue of treating flotation reagent-contaminated wastewater, which poses significant challenges due to pH variability in mining areas. A study published in the Chemical Engineering Journal explores the use of metal-free biochar-based materials (KBBC) activated with potassium chloride (KCl) and combined with persulfate (PS) for effective wastewater treatment across a broad pH range (3.6 to 10.4). This research highlights the potential of KBBC/PS systems in degrading aniline aerofloat (AAF), a common flotation reagent.

The process leverages the enhanced graphitization of biochar through ball milling and the increased carbonyl groups facilitated by KCl, which boosts persulfate activation. Experimental results indicate that under acidic and neutral conditions, the degradation of pollutants is primarily driven by superoxide radicals and direct electron transfer. Conversely, under alkaline conditions, a variety of active species, including hydroxyl radicals (•OH) and sulfate radicals (SO4•−), as well as singlet oxygen, play a significant role.

Furthermore, continuous flow experiments confirmed the practical applicability of the KBBC/PS system in real-world scenarios, suggesting its effectiveness in treating mining wastewater with fluctuating pH levels. This study not only advances the understanding of persulfate activation by metal-free carbon-based materials but also expands their potential application in environmental remediation, particularly in the context of mining operations. This innovative approach offers a promising solution for mitigating the environmental impact of mining activities by efficiently degrading persistent pollutants in wastewater.