Phosphate and ammonium adsorption of the modified biochar based on Phragmites australis after phytoremediation.
To effectively remove N and P from eutrophic water, the Phragmites australis after phytoremediation was harvested for preparation of modified biochar. The MgCl2-modified biochar (MPB) was successfully synthesized at 600 °C under N2circumstance. 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 NH4-N and PO4-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 Mg2+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.
Department of Environmental Engineering, Zhejiang University, Zhejiang, 310058, People's Republic of China.
Yu-Peng
YP
Gong
Department of Environmental Engineering, Zhejiang University, Zhejiang, 310058, People's Republic of China.
Zhi-Yi
ZY
Ni
Department of Environmental Engineering, Zhejiang University, Zhejiang, 310058, People's Republic of China.
Zhao-Zhao
ZZ
Xiong
Department of Environmental Engineering, Zhejiang University, Zhejiang, 310058, People's Republic of China. chenglihua@zju.edu.cn.
Li-Hua
LH
Cheng
Department of Environmental Engineering, Zhejiang University, Zhejiang, 310058, People's Republic of China.
Xin-Hua
XH
Xu
D000327:Adsorption; D064751:Ammonium Compounds / Q000302:isolation & purification*; D001673:Biodegradation, Environmental; D002606:Charcoal / Q000737:chemistry*; D004058:Diffusion; D007700:Kinetics; D015636:Magnesium Chloride; D010710:Phosphates / Q000302:isolation & purification*; D006109:Poaceae; D012996:Solutions; D018508:Water Purification / Q000379:methods*
D064751:Ammonium Compounds; D010710:Phosphates; D012996:Solutions; C540010:biochar; D015636:Magnesium Chloride; D002606:Charcoal
Ammonium adsorption; Eutrophic water; Modified biochar; Phosphate adsorption; Phragmites australis; Tai lake