Elution of Sulfuric Compounds from Na-sulfide Waste for Stable Management at a Disposal Site: an Experimental Investigation

Shun Ishii, Shigeshi Fuchida, Yutaro Takaya, Chiharu Tokoro*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We investigated the dissolution and oxidation behaviors of sulfuric waste from secondary batteries by reacting the waste with synthetic rainwater to examine the optimal management of this waste at a disposal site. Morphological observation and chemical analysis of bulk sulfur (S) wastes revealed heterogeneous distributions of sodium sulfide (NaS) and thiosulfate (Na2S2O3). Leaching experiments using crushed S-waste samples with oxygenated synthetic rainwater for 144 h showed that sulfide ion was the dominant eluent from the less-oxidized sample, whereas sulfate (SO4) and S2O3 ions were released from the well-oxidized sample (left for 6 months). An atmospheric oxidation experiment of S-waste was carried out to elucidate the relationship between sulfide oxidation on the S-waste surface and eluted species. X-ray photoelectron spectroscopy showed rapid oxidation of NaS to Na2S2O3 within the first 72 h, and time-of-flight secondary ion mass spectrometry revealed that the sulfide-oligomers species (S3 and S4) formed after reaction for 336 h. The kinetic analysis indicates that NaS was easily oxidized by atmospheric oxygen. The oxidation rate was 10–100 times higher than that of pyrite. The NaS oxidation and the formation of sulfide oligomer species inhibited the rapid dissolution of sulfuric components from a well-oxidized sample. Most S-waste could be exposed to atmospheric air before disposal; therefore, the main concern for this waste disposal could be SO4 and S2O3 ion dissolution and interaction (redissolution) with toxic compounds such as enhancement of leaching rate of heavy metals due to complex ion formulation.

Original languageEnglish
Article number28
JournalWater, Air, and Soil Pollution
Issue number1
Publication statusPublished - 2022 Jan


  • Atmospheric oxidation
  • Disposal site
  • Dissolution
  • Sulfuric waste

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Ecological Modelling
  • Water Science and Technology
  • Pollution


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