VEGETABLE COMPOSTS FOR SEA-WATER URANIUM EXTRACTION

Composting wood or crop residues by the addition of tanneries sludge a s nitrogen supplement yields products having lower polysaccharides and protein content, but higher relative concentration of lignin material than the starting mixture. When used as sea water uranium adsorbents, the compost products exhibit higher uranium uptake (3.0-100 mug g-1) than parent ligno-cellulosic materials (0.3-9 mug g-1), thus achieving over 10(4)-fold uranium concentration relative to sea water. An addit ional distinguishing feature is the strong pH effect observed on uptak e by products. The results are consistent with the expected change of parent lignin to lignin-humus in the compost product.