Phytoremediation potential of water hyacinth (Eichhornia crassipes) for phenol and cyanide elimination from synthetic/simulated wastewater

Abstract

Water pollution is increasing due to urbanization and industrialization. Waste water pollution raised concern because of its influence on plants and humans. Water hyacinth (Eichhornia crassipes) is used for the removal of pollutants because of its phytoremediation efficiency. In this study, water hyacinth (Eichhornia crassipes) has been tested for simultaneous elimination of phenol and cyanide from mono and binary component aqueous solution in batch systems. The plant was grown at six concentrations of phenol and cyanide in the ratio of (10:1), i.e. 100:10, 200:20, 300:30, 500:50, 700:70 and 1000:100 mg/L in aqueous solution. The effect of process parameters such as initial concentration of phenol and cyanide and pH was evaluated. The plant was found capable of eliminating up to 96.42% of phenol (300 mg/L) and 92.66% of cyanide (30 mg/L) during the 13 days cultivation time at pH 8. The calculated Km of the root length elongation for phenol was 5.20 mm and the Vmax was 12.52 μg phenol/g root/h. However, the calculated Km of the root length elongation for cyanide was 0.39 mm and the Vmax was 14.99 μg cyanide/ g root/h. In the Eichhornia crassipes plant, the biochemical parameters such as chlorophyll, protein and sugar content have been indicated a decreasing trend due to uptake of phenol and cyanide throughout cultivation. Toxicity to 100–1000 mg/L of phenol and 10–100 mg/L of cyanide was measured by measuring the relative transpiration over 13 days. At 100 mg/L of phenol and 10 mg/L of cyanide, only a small reduction in transpiration but no morphological changes were noticed. Both pollutants are absorbed through the root of the Eichhornia crassipes plant by plasmalemma and become accumulated into the root cells and stem of a plant. Thus, this study will be beneficial for the decontamination of highly polluted waste water.