Physicochemical Characterization and Use of Heat Pretreated Commercial Instant Dry Baker's Yeast as a Potential Biosorbent for Cu(II) Removal

• Published in: Clean : soil, air, water air, water, 2014-11, Vol.42 (11), p.1632-1641
• Main Authors: Stanescu, Ana-Maria, Stoica, Ligia, Constantin, Carolina, Lacatusu, Ioana, Oprea, Ovidiu, Miculescu, Florin
• Format: Article
• Language: English
• Subjects: Adsorption; Biosorption; Commercial instant dry yeast; Copper; Heavy metals; Regeneration; Saccharomyces cerevisiae; Spectrum analysis; Yeast
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.201300484

Cu(II) is a naturally occurring microelement, essential for many biochemical pathways but its excess causes serious toxicological problems. This study evaluates the ability of heat pretreated commercial instant dry baker's yeast Saccharomyces cerevisiae (HPIBY) to remove Cu(II) ions from aqueous solutions. The importance of the biosorbent properties in the adsorption process was examined by scanning electron microscopy/energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry/thermogravimetric analysis, and zeta potential analysis. In order to establish the optimum operating parameters, the influence of pH, biosorbent dosage, and initial metal concentration was investigated. The equilibrium adsorption data were analyzed by using Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich adsorption models. The desorption efficiency and the regeneration potential of the HPIBY were evaluated by performing successive biosorption/desorption cycles. The monolayer adsorption capacity (Qm) determined from Langmuir model was 19.53 mg g−1. The maximum removal efficiency, 71.12% was obtained at pH 4.5, for a biosorbent dosage of 0.5% w/v and an initial metal concentration of 50 mg L−1. The zeta potential results suggested that the heat pretreatment enhanced the quantity of organic functional groups with negative charge present on the biosorbent cell walls. The physicochemical characteristics of the biosorbent after metal adsorption and the isotherm data suggested that Cu(II) immobilization by the HPIBY was simultaneously accomplished via electrostatic interactions and chemisorption. In this study, HPIBY was characterized and used as a potential biosorbent for Cu(II) ions removal from aqueous solutions. The FTIR, DSC/TGA and zeta potential results confirmed Cu(II) biosorption by HPIBY. Cu(II) was effectively removed by HPIBY (71.12%). The consecutive biosorption/desorption cycles showed that HPIBY presents a good regeneration potential.