Investigation of Brewery Spent Grain as Adsorbent for Removal of Heavy Metals from Wastewater
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Date
2016-06
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Addis Ababa University
Abstract
Heavy metals are considered a major cause for environmental problems. Several conventional treatment methods have been developed for removal of toxic metal ions from wastewaters. Currently biological materials have received attention for heavy metal removal and recovery due to their good performance, low cost and availability. Among the broad lists of biosorbent materials, brewery spent grain has utilized for this study to remove, lead and chromium from wastewater. BSG was modified with 1M NaOH and afterward it was washed, dried and grinded to have particles sizes of 250-500μm. Lead (II) and Chromium (VI) stock solutions were prepared and from which different concentrations were obtained by serial dilution. Batch adsorption of Lead (II) and Chromium (VI) onto BSG was studied. The results indicated that the maximum percentage removal of lead and chromium was found to be 96.53% and 79.47% at pH= 4 and pH=2 respectively.
The adsorption data of metal ions have been described by the Freundlich and Langmuir isotherm models. The sorption process conformed to both Langmuir and Freundlich isotherms with maximum sorption capacities of 26.3 and 10.75 mg/g for lead and chromium, respectively. Sorption kinetics for lead and chromium(VI) followed pseudo second order with regression coefficients of 0.9999 and 0.9998 respectively. Optimum operating conditions of 10 g/l adsorbent dose, 120 minutes and pH=2 for Cr(VI) and pH= 4 for Pb(II) solution were applied to remove lead and chromium ions from real electroplating wastewater. The results showed that brewery spent grain reduced lead ions from its initial concentration of 82 mg/l to 38.37 mg/l while chromium ion was reduced from 156.9 mg/l to 88.73 mg/l. Therefore, it can be concluded that modified spent grain as a new effective adsorbent has potential for Pb(II) and Cr(VI) removal from aqueous solutions.
Basic terms: Brewer’s Spent Grain, Lead, Chromium (VI), sorption, Isotherm, Kinetics, wastewater
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Brewer’s Spent Grain, Lead, Chromium (VI), Sorption, Isotherm, Kinetics, Wastewater, wastewater