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Kinetics of Nutrient Removal by Nano Zero‐Valent Iron under Different Biochemical Environments
Author(s) -
Xu Shengnan,
Hu Zhiqiang
Publication year - 2015
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143014x13975035525582
Subject(s) - zerovalent iron , anoxic waters , chemistry , anaerobic exercise , denitrification , anammox , nitrate , environmental chemistry , phosphorus , nitrogen , ammoniacal nitrogen , heterotroph , ammonium , nitrite , nutrient , denitrifying bacteria , bacteria , biology , organic chemistry , physiology , genetics , adsorption
The effectiveness of nano zero‐valent iron (NZVI; an average size of 55 nm at a concentration of 200 mg Fe/L) in nutrient removal was determined under anaerobic, anoxic, and aerobic conditions. Compared to the rate of reduction of nitrate nitrogen (‐N) to ammoniacal nitrogen ( ‐N) by NZVI alone, the presence of activated sludge increased the rate of complete reduction by 300%. About 31% of ‐N was converted to ‐N through NZVI‐facilitated dissimilatory nitrate reduction to ammonium, while 56% of ‐N was removed by heterotrophic denitrification. The presence of sludge reduced the rates of phosphorus removal by NZVI, with the first‐order reaction rate constants of 0.06/hour, 0.42/hour, and 0.18/hour under anaerobic, anoxic, and aerobic conditions, respectively. The highest phosphorus removal efficiency (95%) by NZVI was observed under anoxic abiotic conditions, whereas the efficiency dropped to 31% under anaerobic biotic conditions, which was attributed to significant sludge‐facilitated NZVI agglomeration.