The Power of Potassium: A Smart Solution to Remove Toxic Chromium from Water

This study introduces a novel hexavalent chromium removal approach using a potassium bicarbonate-modified pyrite/porous biochar composite. Demonstrating effectiveness over a wide pH range, the composite’s Fe(II)/Fe(III) redox cycle, facilitated by potassium, ensures continuous chromium reduction. The findings contribute insights into sustainable wastewater treatment solutions.

March 6, 2024

1–2 minutes

Zhao, Li, et al (2024) Efficient Cr(VI) removal by pyrite/porous 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: Critical role of potassium salt and sulphur. *Environmental Pollution.* https://doi.org/10.1016/j.envpol.2024.123641

In this study, a one-step process yielded a potassium bicarbonate-modified pyrite/porous biochar composite (PKBC) for efficient hexavalent chromium (Cr(VI)) removal from wastewater. The composite exhibited significant Cr(VI) removal within a broad 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 range (2–11) and demonstrated resistance to interference from complex ions. The addition of potassium bicarbonate enhanced pore structure and facilitated the release of Fe2+, attributing to the Fe(II)/Fe(III) redox cycle responsible for Cr(VI) reduction. Sulphur species played a crucial role in maintaining the Fe(II)/Fe(III) cycle through electron transfer with iron, ensuring continuous reduction capacity. The removal rate remained above 85% in actual water samples, showcasing practical applicability.

The study addresses the environmental risk posed by Cr(VI) accumulation resulting from industrial manufacturing. Hexavalent chromium is known for its significant toxicity, emphasizing the necessity to regulate its environmental concentration. The PKBC composite utilized pyrite, a sulphide ore rich in iron, loaded onto biochar as a support material. This approach aimed to overcome limitations like agglomeration and low dispersibility associated with small-size natural pyrite.

Furthermore, the introduction of potassium bicarbonate proved instrumental in enriching the biochar’s pore structure, providing more loading sites for pyrite, and catalytically improving composite material properties. The research not only contributes to the development of an effective Cr(VI) treatment method but also sheds light on the critical role of potassium bicarbonate in the system. Overall, this work introduces a promising approach for wastewater remediation, offering valuable insights into the mechanisms of hexavalent chromium removal and the influence of potassium bicarbonate.