Phosphate and ammonium adsorption of the modified biochar based on Phragmites australis after phytoremediation

• Published in: Environmental science and pollution research international Vol. 24; no. 9; pp. 8326 - 8335
• Main Authors: Gong, Yu-Peng, Ni, Zhi-Yi, Xiong, Zhao-Zhao, Cheng, Li-Hua, Xu, Xin-Hua
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2017; Springer Nature B.V
• Subjects: Adsorption; Ammonium; Ammonium Compounds - isolation & purification; ammonium nitrogen; Aquatic plants; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; biochar; Biodegradation, Environmental; Charcoal; Charcoal - chemistry; Computer simulation; Diffusion; Diffusion models; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Eutrophic environments; Eutrophic lakes; Eutrophic rivers; Eutrophic waters; Eutrophication; Functional groups; Harvesting; Inflow; Kinetics; Lakes; Magnesium; Magnesium Chloride; nitrogen; Particle diffusion; phosphates; Phosphates - isolation & purification; Phragmites australis; Physiochemistry; Phytoremediation; Poaceae; Research Article; Rivers; Solutions; Waste Water Technology; Water inflow; Water Management; Water Pollution Control; Water Purification - methods; Water treatment; Ammonium adsorption; Tai lake; Modified biochar; Phosphate adsorption; Eutrophic water; Phragmites australis
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-017-8499-2

To effectively remove N and P from eutrophic water, the Phragmites australis after phytoremediation was harvested for preparation of modified biochar. The MgCl 2 -modified biochar (MPB) was successfully synthesized at 600 °C under N 2 circumstance. The physiochemical characteristics, the adsorption capacity for N and P in the simulated solution, and their adsorption mechanism of MPB were then determined, followed by the treatment of eutrophic water of Tai lake and its inflow river from agricultural source. The results demonstrated that the MPB presented high adsorption capacity to both simulated NH 4 -N and PO 4 -P with the maximum adsorption capacity exceeding 30 and 100 mg g −1 , respectively. The entire ammonium adsorption process could be described by a pseudo-second-order kinetic model whereas the phosphate adsorption process could be divided into three phases, as described by both intra-particle diffusion model and the pseudo-first-order kinetic. It was further found that the dominant mechanism for ammonium adsorption was Mg 2+ exchange instead of functional groups and surface areas and the Mg-P precipitation was the main mechanism for phosphate adsorption. The MPB also showed high removal ratio of practical TP which reached nearly 90% for both the water in Tai lake and its agricultural source. It suggested that MPB based on harvested P. australis was a promising composite for eutrophic water treatment and it could deliver multiple benefits. Graphic abstract