Continuous-flow metal biosorption in a regenerable Sargassum column

• Published in: Water research (Oxford) Vol. 37; no. 2; pp. 297 - 306
• Main Authors: Volesky, B., Weber, J., Park, J.M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2003; Elsevier Science
• Subjects: Adsorption; Applied sciences; Biomass; Biosorbent regeneration; biosorption; Column biosorption; Copper - chemistry; Copper - isolation & purification; copper removal; Cu biosorption; Exact sciences and technology; Hydrogen-Ion Concentration; Multi-cycle biosorption; Other industrial wastes. Sewage sludge; Pollution; Sargassum biosorbent; Sargassum filipendula; Seaweed - chemistry; Wastes; Water Pollutants - isolation & purification; Water Purification - methods; Water treatment and pollution; Multi-cycle biosorption; copper removal; Cu biosorption; Column biosorption; Biosorbent regeneration; Sargassum biosorbent; Packed bed; Algae; Desorption; Biomass; Sargassum; Mass transfer; Hydrochloric acid; Continuous process; Sorption; Heterokontophyta; Biosorption; Phaeophyceae; Thallophyta
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(02)00282-8

Metal biosorption behavior of raw seaweed S. filipendula in ten consecutive sorption–desorption cycles has been investigated in a packed-bed flow-through column during a continuous removal of copper from a 35 mg/L aqueous solution at pH 5. The elutant used was a 1% (w/v) CaCl 2/HCl-solution at pH 3. The sorption and desorption was carried out for an average of 85 and 15 h, respectively, representing more than 41 days of continuous use of the biosorbent. The weight loss of biomass after this time was 21.6%. The Cu-biosorption capacity of the biomass, based on the initial dry weight, remained relatively constant at approximately 38 mg Cu/g. Loss of sorption performance was indicated by a shortening breakthrough time and a broadening mass-transfer zone. The column service time, considered up to 1 mg Cu/L in the effluent, decreased continuously from 25.4 h for the first to 12.7 h for the last cycle. The critical bed length, representing the mass-transfer zone, increased almost linearly from 28 to 34 cm. “Life-factors” for S. filipendula were found to be 0.0008 h −1 for the breakthrough time and 0.008 cm/h for the critical bed length, using an exponential decay and linear fitting functions, respectively. Regeneration with CaCl 2/HCl at pH 3 provided elution efficiencies up to 100%. Maximum concentration factors were determined to be in the range 16–44, a decreasing tendency was observed with an increasing exposure time.