Production of Biosorbents from Waste Olive Cake and Its Adsorption Characteristics for Zn2+ Ion

Abstract

In this study, waste olive cake (OC) was utilized as the raw material for the production of biosorbents by chemical treatment and its adsorption capacity for zinc ion was evaluated. Tests were conducted with the total biomass (T) and with the fraction > 2.00 mm (P), in order to determinate the influence of this fractionation step on subsequent treatments. Two chemical agents were used: sulfuric acid and sodium hydroxide. The parameters studied include physical and chemical properties of materials, contact time, pH, adsorbent dose and initial concentrations. The kinetic data were best fitted to the pseudo-second order model. Zinc binding is strongly pH dependent, with more zinc ions bound at a higher pH (5-7 in a range of 3-7). Both Langmuir and Freundlich models are well suited to fit the data on sorption of zinc by OC. Data on sorption of zinc by waste olive cake treated with sulfuric acid (OC-H) was better described by the Freundlich model. Zinc sorption by waste olive cake treated with sodium hydroxide (OC-OH) was better described by the Langmuir model. Results show OC-OH is a biosorbent with a superior adsorption capacity for zinc than OC-H. The maximum adsorption capacity obtained from the Langmuir isotherms increases in the order (mg/g): OC-HT (14), OCT (22) and OC-OHT (27). Results also indicate that the previous fractionation step doesn´t produce a biosorbent with a superior adsorption capacity

Removal of heavy metals by biosorption

“…The removal of Zn 2? from effluents is a major problem due to the difficulty in treating such wastewaters by conventional treatment methods (Fernando et al 2009). Hence, substantial research is currently under progress to find suitable, highefficiency and low-cost natural sorbents for Zn 2?…”

The Suitability of Jatropha Seed Press Cake as a Biosorbent for Removal of Hexavalent Chromium from Aqueous Solutions

“…This technology is based on the capacity of many biological materials to bind and remove heavy metals from aqueous effluents (Vieira and Volesky 2000;Volesky 2001). It employs the use of various divergent biomass, such as algae (Rathinam et al 2010), seaweeds (Baral et al 2008), bacteria (Wang et al 2010), fungi (Ahluwalia and Goyal 2010), agrowastes including husk (Boucher et al 2008), fibers (Makehelwala et al 2009), sawdust (Ting et al 2010), tea waste (Prabhakaran, Vijayaraghavan, and Balasubramanian 2009), bagassae (Samadi et al 2009), seed cake (Boucher et al 2008;Fernando et al 2009), etc. Seed cakes are the secondary by-product generated after the oil extraction from oleaginous seeds, which are poorly utilized.…”

CHAPTER 15. Biosorption of Metals – From the Basics to High Value Catalysts Production

“…37 The removal of Zn 21 from effluents is a major problem due to the difficulty in treating such wastewaters by conventional treatment methods. 37,67,68 Biosorption could be the appropriate alternative and several studies reported in the literature for the removal of this metal support the feasibility of this removal technique. 67,68…”