Phytoremediation of Copper-Contaminated Water with Pistia stratiotes in Surface and Distilled Water

Abstract

Copper contamination of industrial waste streams is increasingly common with copper used in an array of industrial processes. Phytoremediation of copper-contaminated water with Pistia stratiotes presents a cost-effective, efficient and uncomplicated alternative for copper removal from industrial wastewater. This study examines the ability of Pistia stratiotes to remove copper from distilled water representing a highly nutrient-deficient medium and natural surface water containing plant nutrients inherently. Control and experimental sets were set up with growth solutions of distilled water and natural surface water spiked with 5 g/mL, 10 g/mL, 15 g/mL, 20 g/mL and 25 g/mL copper. The control sets were devoid of Pistia stratiotes while the experimental sets contained Pistia stratiotes. Copper concentration and pH of the solutions were tracked over 10 days. This study revealed the ability of Pistia stratiotes to remove copper in both types of growth solution with contamination level ranging from 5 to 25 mg/L and pointed to its ability to phytoremediate higher level of copper contamination. Pistia stratiotes also raised the pH of the growth solutions. Copper removal from both types of growth solution demonstrated a predominantly first-order elimination kinetics except for copper concentrations above 15 mg/L in distilled water where the zero-order elimination kinetics predominated. Copper removal efficiency decreased with increasing copper concentrations in both types of growth solution with removal efficiency in natural surface water growth solutions consistently higher. It highlights the ability of Pistia stratiotes to phytoremediate highly nutrient-deficient and natural surface water media.