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a b s t r a c tThis work evaluated the fibre fruit lufa (FL) as a biosorbent thanks its ability to remove cadmium ions from aqueous media in a batch process. The effect of the experimental parameters such as initial cadmium concentrations, biosorbent dose, initial pH, ionic strength and temperature is investigated through a number of batch biosorption experiments. The results show that the increase of initial concentration, time contact, dose of FL, the temperature and pH has a positive impact on the % removal of Cd (II). However, the ionic strength has a negative effect on the % removal of metal. The biosorption kinetic uptake for cadmium onto FL at various initial pH solutions was analyzed using Lagergreen pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The biosorption kinetics for the cadmium on this biosorbent was best represented by the pseudo-second order kinetic model and the diffusion mechanism reveal that intraparticle diffusion is not the only rate limiting step. The experimental data biosorption equilibrium at different temperatures (298-328 K) were analyzed by the Langmuir, Freundlich, Temkin and Kiselev models. The results indicate that the Langmuir model, Freundlich and Temkin suggest that they were suitable to represent the experimental equilibrium data for the biosorption of cadmium onto FL. The monolayer biosorption capacity (q m ) by the Langmuir model was found to be 97.33 mg/g at 25°C. Thermodynamic parameters show that the biosorption process of FL is endothermic and the ∆G° values are negative, which indicates that the biosorption is spontaneous phenomena.

a b s t r a c tThe aim of the present work was to investigate the feasibility of Okoume (Aucoumea Klaineana) sawdust (OS) for Rhodamine B (RhB) adsorption from aqueous media. OS surface was characterized by the functional organic groups by the Boehm titration method, scanning electron microscopy (SEM) and isoelectric potential (pH ZPC ). The adsorption of RhB on OS material was studied as a function of solution pH 2-10, sodium chloride (0-5000 mg/L), solution temperature (25-45°C), contact time and initial concentration (5-30 mg/L). The influence of these parameters on the amount of RhB adsorbed was studied using the batch process. The results show that the increase of initial concentration, the temperature has a positive impact on the adsorption of RhB. However, the sodium chloride and pH have a negative effect to the dye removal, and a maximum adsorption was achieved at pH 3.0. Experimental kinetics data at different initial dye concentrations were analyzed using Lagergren pseudo-first-order, pseudo-second-order and Elovich models, and were found well described by the pseudo-second order model. The results for the mechanism adsorption, the intraparticle diffusion for all period was not the only rate-limiting step, it seems that other processes might implicate in control the rate. Equilibrium isotherm data at different temperatures (25-45°C) were analyzed according to Langmuir and Freundlich equations, and the adsorption isotherm was found to follow the Langmuir model. The monolayer adsorption capacity (q m ) was found to be 79.65 mg/g at 25°C. Furthermore, thermodynamic parameters such as ∆G°, ∆S° and ∆H° were calculated, and the results suggest that the adsorption is spontaneous, a physical process and endothermic in nature.