Abstract
The potential of uncharred biomaterial derived from dry leaves of Ficusbenjamina (Family: Moraceae,local name: Weeping Fig) plant to remove Cr(VI) from aqueous samples was investigated. In the present work, treatment of dilute acids was used for activating the adsorption centres on the biomass instead of cumbersome charring process. The plant material was characterized using FT-IR, FE-SEM and EDX. Various influencing factors such as pH of equilibrating solution, contact time, Cr (VI) concentrations, adsorbent dose and temperature were optimized to obtain maximum sorption efficacy. The interactions among the biomaterial and Cr (VI) in water were studied by fitting the sorption data in four different adsorption isotherms. The data fitting and experimental evidences indicated formation of monolayer of Cr(VI) over the biomass surface. The process followed pseudo-second order kinetics and was thermodynamically spontaneous under laboratory conditions and reached equilibrium in 24 hours. Maximum adsorption capacity of 56.82 mg/g was obtained at the pH 2 when the concentration before adsorption was 200 mg L−1 of Cr(VI) with 24 hours of equilibration time and 2.50 g L−1 of dose of biomaterial at room temperature. The sorption efficiency was found to be better than many charred bio-based materials.
Highlights
The most common industrial contaminants are heavy metals in their stable oxidation states
Untreated Ficus benjamina biomass (FBB) showed around 42% of Cr (VI) sorption, it was observed that the adsorbed Cr (VI) leaches out after 24 h
The present study has resulted into use of uncharred leaves of Ficus benjamina an effective adsorbent for Cr(VI) from aqueous solutions
Summary
The most common industrial contaminants are heavy metals in their stable oxidation states Their salts are soluble and highly mobile in water bodies and removing them presents a major challenge. There are various methods by which Cr(VI) can be removed from waste water that include chemical precipitation, membrane filtration, reverse osmosis and ion exchange ; these methods are either expensive or less efficient[7,8]. Over these methods bio-sorption serves as an effective strategy as it is cost effective, eco-friendly and logistically easier. Advantage of the method is better adsorption efficiency and reduction in the processing steps during material preparation
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