The nanoscale zero valent iron supported on pillared clay (NZVI/PILC) was prepared, and used for nitrate
removal with the objective of enhanced efficiency. The composite NZVI/PILC was characterized by transmission
electron microscope (TEM), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET). Good
dispersion of NZVI particles (ca. 30–70 nm) in the clay phase was observed. The removal efficiency of
nitrate by this composite was investigated, and compared with commercial iron powder and NZVI containing
the same amount of iron. Results showed nitrate could be completely removed by NZVI/PILC
within 120 min. This efficiency was not only much higher than that (62.3%) by NZVI alone, but also
superior to the sum (71.5%) of reduction by NZVI plus adsorption (9.19%) by PILC. The kinetic studies
indicated that the rate of nitrate removal was positively related to the adsorption. So we suggested that
the adsorption of nitrate by PILC enhanced the mass transfer of nitrate from solution to iron surface,
therefore accelerated the reduction rate. The end-products of nitrate reduction by NZVI/PILC were identified
as ammonium and nitrogen gas, implying NZVI/PILC may help cut down the total nitrogen amount
in water.
The nanoscale zero valent iron supported on pillared clay (NZVI/PILC) was prepared, and used for nitrateremoval with the objective of enhanced efficiency. The composite NZVI/PILC was characterized by transmissionelectron microscope (TEM), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET). Gooddispersion of NZVI particles (ca. 30–70 nm) in the clay phase was observed. The removal efficiency ofnitrate by this composite was investigated, and compared with commercial iron powder and NZVI containingthe same amount of iron. Results showed nitrate could be completely removed by NZVI/PILCwithin 120 min. This efficiency was not only much higher than that (62.3%) by NZVI alone, but alsosuperior to the sum (71.5%) of reduction by NZVI plus adsorption (9.19%) by PILC. The kinetic studiesindicated that the rate of nitrate removal was positively related to the adsorption. So we suggested thatthe adsorption of nitrate by PILC enhanced the mass transfer of nitrate from solution to iron surface,therefore accelerated the reduction rate. The end-products of nitrate reduction by NZVI/PILC were identifiedas ammonium and nitrogen gas, implying NZVI/PILC may help cut down the total nitrogen amountin water.
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