Enhanced nitrogen and phosphorus removal from eutrophic lake water by Ipomoea aquatica with low-energy ion implantation

• Published in: Water research (Oxford) 2009-03, Vol.43 (5), p.1247-1256
• Main Authors: Li, Miao, Wu, Yue-Jin, Yu, Zeng-Liang, Sheng, Guo-Ping, Yu, Han-Qing
• Format: Article
• Language: English
• Subjects: Applied sciences; bioaccumulation; Biodegradation, Environmental; Biomass; China; Environmental Restoration and Remediation - methods; enzyme activity; Eutrophication; Exact sciences and technology; Fresh Water - chemistry; Freshwater; Germination; Hydroponics; Ion implantation; Ions; Ipomoea - enzymology; Ipomoea - growth & development; Ipomoea - metabolism; Ipomoea aquatica; lakes; nitrate reductase; nitrogen; Nitrogen - isolation & purification; Nutrients; Other industrial wastes. Sewage sludge; peroxidases; phosphorus; Phosphorus - isolation & purification; Phytoremediation; plant growth; Pollution; Quaternary Ammonium Compounds; Wastes; Water Pollutants, Chemical - isolation & purification; water pollution; Water spinach; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2008.12.013

Ipomoea aquatica with low-energy N + ion implantation was used for the removal of both nitrogen and phosphorus from the eutrophic Chaohu Lake, China. The biomass growth, nitrate reductase and peroxidase activities of the implanted I. aquatica were found to be higher than those of I. aquatica without ion implantation. Higher NO 3–N and PO 4–P removal efficiencies were obtained for the I. aquatica irradiation at 25 keV, 3.9 × 10 16 N + ions/cm 2 and 20 keV 5.2 × 10 16 N + ions/cm 2, respectively ( p < 0.05). Moreover, the nitrogen and phosphorus contents in the plant biomass with ion implantation were also greater than those of the controls. I. aquatica with ion implantation was directly responsible for 51–68% N removal and 54–71% P removal in the three experiments. The results further confirm that the ion implantation could enhance the growth potential of I. aquatica in real eutrophic water and increase its nutrient removal efficiency. Thus, the low-energy ion implantation for aquatic plants could be considered as an approach for in situ phytoremediation and bioremediation of eutrophic waters.