Potential of Chitosan (Chemically Modified Chitin) for Extraction of Lead-Arsenate Contaminated Soils

ABSTRACT

Arsenic, lead, and phosphorous contamination in soils represents a health risk. Chitosan (poly-N-acetyl glucosamine) inexpensive by-product derived from chitin has been used as a metals adsorbent. Objectives of this research were to evaluate the effectiveness of chitosan solution for arsenic, lead, and phosphorous extraction from lead-arsenate contaminated soils, and evaluate the effectiveness of protonated chitosan flakes (PCF) and ferric hydroxide chitosan beads (Fe(III)-CB) for water-soluble As removal from these soils. Percentage of arsenic, lead, and phosphorous removed from the soils by chitosan solution ranged from 0.96% to 17%, 1.80% to 31%, and 0.66% to 11%, respectively. Percentage of water-soluble arsenic removed by PCF and by Fe (III)-CB ranged from 12% to 47% and 36% to 77%, respectively. Averaged over soils, Fe (III)-CB removed slightly more arsenic (As) (42 mg kg⁻¹) compared to Mehlich III (40 mg kg⁻¹) extractant. Results indicate potential for the use of chitosan as an extraction for lead-arsenate contaminated soils.

KEYWORDS:

• Adsorption
• by-products
• chitosan
• extraction
• flakes

Acknowledgments

The authors would like to acknowledge the technical assistance of M. Gesese in conducting the study. Abigail Padilla-Rodríguez would like to thank Dr. Félix Román and Dr. Oscar Perales for their help.