Phosphorus removal by hydrotalcite-like compounds (HTLcs)

Hydrotalcite-like compounds (HTLcs), which are also called anionic clay minerals or Layered Double Hydroxides (LDHs), can be formulated by M(II)(1-x)M(III)(x)(OH)(2)(A(n-))(x/n)yH(2)O. This chemical, which has anoin exchange capacity, could be an alternative chemical for phophorus removal. The phosphate uptake by HTLcs containing Cl- as the interlayer anion was found to be 2.35-2.83 meg of P/g. The most serious obstacle anion against phosphate uptake was bicarbonate because the selectivity of carbonate by LDH is the highest. To investigate the possibility of LDH's recycle employing the ''Memory effect'', calcined LDH (CLDH) was repeatedly used for 6 times. From the fifth time, the final phosphate uptake capacity decreased. The consecutive reconstruction mechanism of CLDH is not yet known but it is certain that the possibility of LDH's recycle is promising. Copyright (C) 1996 IAWQ.