Agricultural waste of sugarcane bagasse as efficient adsorbent for lead and nickel removal from untreated wastewater: Biosorption, equilibrium isotherms, kinetics and desorption studies

Highlights

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  Removal efficiency of 89.31 % (Pb) and 96.33 % (Ni) by sugarcane bagasse.

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  Optimum pH 6.0; temperature, 30 °C; contact time, 90 min. and adsorbent dose of 0.5 g.

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  Fitted by Freundlich and pseudo-second-order models.

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  Adsorption capacity of 1.61 mg/g (Pb) and 123.46 mg/g (Ni).

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  Desorption efficiency of 85.2 % by nitric acid.

Abstract

The aim of this study was to evaluate the removal of Pb (II) and Ni (II) from untreated waste water using sugarcane bagasse and possible desorption of the metal ions from the adsorbent for effective re-use. The effects of pH (4-6), temperature (30−70 °C), contact time (30−150 min) and adsorbent dosage (0.3−0.7 g) were examined. Optimum conditions for the removal efficiencies of Pb (89.31 %) and Ni (96.33 %) were pH, 6.0; temperature, 30 °C; contact time, 90 min. and adsorbent dosage, 0.5 g. The maximum monolayer adsorption capacities of Pb (II) and Ni (II) were 1.61 mg/g and 123.46 mg/g respectively, by fitting the equilibrium data to the Langmuir isotherm model. Freundlich isotherm and pseudo second order kinetic models were best fitted for Pb (II) and Ni (II) uptake. Desorption of the metal ions from the metal-loaded bagasse was best performed by HNO ₃ with removal efficiency of 85.2 %. Therefore, sugarcane bagasse has a high potential for removal of heavy metals from waste water and can be re-used at any time after desorption without losing its efficiency.