journal article·2025-12-17Open access

Anionic Effects on Flocculation and Consolidation of Sediments Contaminated by Heavy Metals

Wenjing Sun, Yijie Sun, Yitian Lu

Applied Sciences· Volume 15· Issue 24

Abstract

The remediation of heavy metal-contaminated sediments is a significant environmental challenge. While cation effects are well studied, the influence of common co-existing anions on treatment efficiency remains poorly quantified. This study systematically investigates the effects of nitrate (NO3−), chloride (Cl−), and sulfate (SO42−) ions on the flocculation and consolidation of copper (Cu)- and zinc (Zn)-contaminated sediments through settling column tests, turbidity measurements, and oedometer consolidation tests. Results demonstrated that NO3− achieved the highest flocculation efficiency, with a final settling height of 3.52 cm and a supernatant turbidity of 4.6 NTU, and the best consolidation performance, with a coefficient of 1.27 × 10−3 cm2/s. In contrast, SO42− yielded the poorest outcomes. The superior performance of NO3− is attributed to its low charge density, which promotes the formation of denser flocs. These findings underscore that anion selection is a critical factor for optimizing sediment dewatering processes, suggesting that strategies favoring nitrate conditions can enhance the efficiency of techniques like pressure filtration and vacuum pre-compression.
Source: crossref · Quality: baseline

Research context

OpenAlex topics: Coagulation and Flocculation Studies · Environmental remediation with nanomaterials · Constructed Wetlands for Wastewater Treatment

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China

Funding

the National Natural Science Foundation of China · the Natural Science Foundation of Shanghai Province

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