1933Algae celk were successfully lmmoblllzed on a sllka substrate and used In a chromatographlc oeparatlon procedure that removed Pb from synthetlc solutlons. Characterlzatlon of the rerln In a chromatographlc extraction mode revealed acceptable flow rates and efflclent metal strlpplng by both HN03 and HCI. VarlaMllty arroclated wlth the growth, harvestlng, Immoblllzatlon, and column packlng procedures were evaluated. Results revealed excellent reproduclblllty for the lmmobllltatlon procedure, and the greatest source of varlatlon was arroclated wlth the algae growing process. The adsorption capaclty of the algae redn declined by 15 % over 20 adsorptlon-elutlon cycles, and attempt8 to ldentlfy and control the source (8) of the degradatlon were not succesdul. EquUikkrm parameters govemlng the metal adsorption process were obtalned by Schatchard analyrk, of the Pb blndlng data for both the free and lmmoMllzed algae. Comparlson of the extrapolated saturatlon values for the free (449 f 49 pmol of dtes/g of algae) and Immoblllzed algae (278 f 25 pmol of dtes/g of algae) reveal a 40 % loss of adsorptlon efflclency as a result of the Immoblllzatlon procedure. However, close agreement of the equlllbrlum constants calculated from the slope of the Wed regredon lines at hlgh Pb concentratlons for free (0.031 f 0.003) and lmmoblllzed (0.025 f 0.002) algae Indicate the Immoblllzatlon process ha8 mlnknal effeci on the Integrity of the remalnlng adsorption sltes. The dendty of adsorptlon 8Hes on the algae resln was also measured by a chromatographlc procedure (267 f 6 pmol of sltes/g of algae) and the results are In good agreement wlth the Scatchard method of data analysls.

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Three freshwater heat-killed, lyophilized blue-green algae strains have been characterized as to their ability to accumulate heavy metals with a focus on the utilization of these algae as an analytical preconcentration technique. This study examines the metal uptake in several multicomponent mixtures by using inductively coupled plasma optical emission spectrometry (ICP-OES). Six milligrams of a pure strain of algae was added to 20-mL aliquots of buffered (pH 5.5-6.5) multielement solutions containing 0.1, 0.5, 1.0, 2.0, and 4.0 mg/L of K, Mg, Ca, Fe, Sr, Co, Cu, Mn, Ni, V, Zn, As, Cd, Mo, Pb, and Se. All three algae strains exhibit relatively high adsorption affinities for Fe, Pb, and Cu, with uptake between 70 and 98% at the 4 ppm concentration level. Biosorption occurs for essentially every element with the relative affinities decreasing in the order Pb greater than Fe greater than Cu greater than Cd greater than Zn greater than Mn greater than Mo greater than Sr greater than Ni greater than V greater than Se greater than As greater than Co for Chlorella pyrenoidosa at the 4 mg/L concentration level. Although some minor differences were seen, the other algae strains (Stichococcus bacillaris and Chlamydomonas reinharti) displayed similar adsorption behavior over the concentration range studied, indicating similar cell wall binding sites. Langmuirian isotherms exhibited a minimum of two slopes over the concentration range of 0.1-4.0 mg/L, indicating the probable existence of at least two adsorption mechanisms.

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