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Chemically oxidized pineapple fruit peel biomass has been used as a biosorbent for Cd(II) and Pb(II) removal from aqueous solutions. Fourier transform infrared spectroscopy and scanning electron microscopy techniques were used to characterize the treated pineapple fruit peel. The biosorption efficiency of pineapple fruit peel for Cd(II) and Pb(II) was greatly enhanced after chemical oxidation probably due to introduction of carboxylic and hydroxyl groups onto the biosorbent surface. Biosorption kinetics for both metals was well described by pseudo-second-order kinetic equation and intraparticle film diffusion. Langmuir, Freundlich, and Temkin isotherm models were applied to the biosorption equilibrium data and best results were obtained with Langmuir isotherm model. Maximum monolayer biosorption capacity was found to be 42.10 and 28.55 mg g−1 for Cd(II) and Pb(II), respectively. Thermodynamic study indicates that the biosorption was exothermic and the spontaneity of the process decreases with the ...

This work was aimed to evaluate the adsorptive nature of palm oil mill effluent sludge ash for methylene blue dye removal in aqueous solution. Two types of palm oil mill effluent sludge collected from different treatment ponds, i.e. anaerobic and biopolishing were burnt to ash, and treated with 5 M HCl. The treated and untreated adsorbents were characterized for surface area and morphology. Methylene blue dye adsorption was carried out in laboratory at room temperature, and the adsorption data were analyzed based on equilibrium isotherm and kinetic models. The surface area of ash-adsorbents was found to increase more than 12 times after HCl treatment. The highest surface area recorded was 218 m2/g. Equilibrium data of ash-adsorbents obeyed Langmuir isotherm to linear approximation suggesting the monolayer uptake of methylene blue dye. The highest maximum uptake of 50.7 mg/g methylene blue dye (50% removal) was demonstrated by HCl-treated biopolishing ash-adsorbent at initial concentration of 200 m...

The work was aimed to investigate the effect of heat treatment of manure-compost-based activated carbons on the adsorption of copper from aqueous solution. Activated carbons were characterized according to physical structures and surface functional groups. All equilibrium data of activated carbons formerly treated at different temperatures obeyed Langmuir model to linear approximation. Results showed that copper ions favorably adsorbed onto the mesopores at lower equilibrium concentrations and subsequently changed to the micropores at higher equilibrium concentrations. It was found that the increase in electron density upon heat treatment offered higher tendency for the uniform amount of protons to occupy the surface sites. Analysis of Scatchard plots suggested that the affinity driven by the mesopores toward copper ions was stronger than that of the micropores.