METAL-ION BINDING BY ALGAE AN HIGHER-PLANT TISSUES - A PHENOMENOLOGICAL STUDY OF SOLUTION PH-DEPENDENCE

Several biomaterials derived from blue-green algae and cells and tissu es from some higher plants were tested for their potential to remove m etal ions from solutions at different pH. Most biomaterials displayed pH-dependent binding profiles for Cu(II), Al(III), and Au(III). Howeve r, fragments of cultured Datura cells showed pH-independent binding of Au(III) binding of over 97%. Other biomaterials also showed high affi nity for Cu(II) and Au(III) at pH 5.0. These included freeze dried roo ts and stems of cattail plants (Typha latifolia), the leaves of tumble weeds (Salsola spp.). alfalfa sprouts (Medicago sativa), and sphagnum peat. Al(III) binding by most biomaterials was low. An exception to t his observation was Al(III) binding to alfalfa sprouts. The highest bi nding capacities for copper were exhibited by sphagnum peat moss and a lfalfa sprouts with 30 and 18 mg Cu/g biomaterial, respectively. The r eduction of Au(III) to Au(O) by several of these biomaterials was obse rved.