2004 Volume 12 Issue 4 Pages 243-248
A paper sludge ash was subjected to NaOH hydrothermal condition. The component minerals of this modified paper sludge ash (MPS) were NaP1-type zeolite, gehlenite, talc, quartz and anatase, and their contents determined by standard addition method with X-ray diffraction measurement were 42.5, 20.5, 4.1, 3.0 and 1.3 mass%, respectively. The 28.5 mass% as the rest of MPS contents was amorphous calcium aluminosilicate hydrate (CASH), which was probably formed from Ca in paper additives, Al in water-clarifying reagent and Si in water glass. As a result of Pb adsorption experiments, the maximum adsorption on MPS was 20.58 μmol g-1, which was higher than those on pure mineral species such as NaP1 and gehlenite. It was thought that the large adsorption of MPS was owing to an excellent adsorption of CASH in MPS. The molecular orbital calculation supported a speculation that the Pb adsorption on CASH was principally specific one with which silanol groups were concerned.
