Table 1.
Weight variation during purification, Fe content, specific surface area, and mean diameter
| CEINs | Weight variation (wt%) |
Fe content (wt%) |
Surface area (m2/g) |
Mean diameter (nm) |
|---|---|---|---|---|
| Fe@C/Fe | N.A. | 69 | 60 | 56 |
| Fe@C | −33 | 50 | 77 | 52 |
| Fe@C–COOH | −47 | 40 | 95 | 46 |
| Fe@C–(CH2)2COOH | +37 | 35 | 75 | 47 |
Fe@C/Fe the raw CEINs containing carbon-coated iron and uncoated iron particles, Fe@C the purified Fe@C/Fe due to removing the uncoated iron particles; Fe@C–COOH the Fe@C oxidized in H2SO4/HNO3, Fe@C–CH 2 CH 2 COOH Fe@C functionalized by attack of 2-carboxyethyl (.CH2CH2COOH) radicals