Extraction and retrieval of potassium from water hyacinth ( Eichhornia crassipes)

Abstract

Studies were carried out on extraction and retrieval of potassium from water hyacinth ( Eichhornia crassipes). The stem and leaf were subjected to 13 treatments. The highest rate of K removal following HCl treatment was 69.7% K. Most effective removal of suspended organic substances, Ca 2+ and Mg 2+ were achieved at pH approximately 13, when 88.0% of K remained in filtrate. Maximum K in precipitate following this step was achieved with tartaric acid additions at n C 4 H 6 O 6 / n K + of 1.72 when precipitating at 4 °C for 3 h, which resulted in 72.3% of K removal from the solution. Over the entire process, 44.3% of K in the dried stem–leaf sample of water hyacinth was retrieved in the form of KC 4H 5O 6. This process demonstrated the potential for use of water hyacinth as a resource of potassium to produce potassium salts and provide a valuable end use for the plant, which could be highly invasive in aquatic ecosystems.