Applications of Citric Acid Industrial Wastewater and Phosphonates for Soil Remediation: Effects on Temporal Change of Cadmium Distribution

Ying Ying Gu, Albert T. Yeung, Chiu Wa Tsang, Rong Bing Fu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

8 Citations (Scopus)

Abstract

Citric acid industrial wastewater (CAIW) and phosphonates are potentially useful for enhancing remediation of metal-contaminated soil. This study aimed to investigate the effects of these enhancement agents on temporal change of Cd distribution in a clayey soil, which probably correlates with the metal lability and bioavailability in the environment. Sequential extractions were performed on the soil samples from batch desorption experiments between 5 and 4320 min. The CAIW primarily enhanced Cd extraction from weakly bound fractions (i.e., exchangeable and carbonate fractions), which was relatively fast and took place in the first 60 min. On the other hand, (nitrilotrimethylene)-triphosphonic acid (NTMP) and ethylene diaminetetra-methylenephosphonic acid (EDTMP) provided a more significant Cd extraction from exchangeable, carbonate, and oxide fractions, with the change of Cd distribution occurring over the first 300 min. The differences in the extent and temporal change of metal extraction reflected the weaker complexation strength of CAIW compared to that of NTMP and EDTMP. Moreover, an increase of pH from 4 to 10 shifted the remaining Cd from exchangeable fraction to carbonate and oxide fractions. These distribution changes indicated that both CAIW and phosphonates were efficient at removing weakly bound Cd fractions in a short period of time, but alkaline conditions could hinder their effectiveness.
Original languageEnglish
Pages (from-to)876-889
Number of pages14
JournalSoil and Sediment Contamination
Volume22
Issue number8
DOIs
Publication statusPublished - 1 Nov 2013

Keywords

  • Citric acid industrial wastewater
  • metal distribution
  • phosphonates
  • soil remediation

ASJC Scopus subject areas

  • Environmental Chemistry
  • Soil Science
  • Pollution
  • Health, Toxicology and Mutagenesis

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