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Go to Editorial ManagerIn this study, low cost biosorbent ? inactive biomass (IB) granules (dp=0.433mm) taken from drying beds of Al-Rustomia Wastewater Treatment Plant, Baghdad-Iraq were used for investigating the optimum conditions of Pb(II), Cu(II), and Ni(II) biosorption from aqueous solutions. Various physico-chemical parameters such as initial metal ion concentration (50 to 200 mg/l), equilibrium time (0-180 min), pH (2-9), agitation speed (50-200 rpm), particles size (0.433 mm), and adsorbent dosage (0.05-1 g/100 ml) were studied. Six mathematical models describing the biosorption equilibrium and isotherm constants were tested to find the maximum uptake capacities: Langmuir, Freundlich, Redlich–Peterson, Sips, Khan, and Toth models. The best fit to the Pb(II) and Ni(II) biosorption results was obtained by Langmuir model with maximum uptake capacities of 52.76 and 36.97 mg/g for these two ions respectively. While for Cu(II) the corresponding value was 38.07 mg/g obtained with Khan model. The kinetic study demonstrated that the optimum agitation speed was 400 rpm, at which the best removal efficiency and/or minimum surface mass transfer resistance (MSMTR) was achieved. A pseudo-second-order rate kinetic model gave the best fit to the experimental data (R2=0.99), resulting in mass transfer coefficient values of 42.84× , 1.57× , and 2.85× m/s for Pb(II), Cu(II), and Ni(II) respectively. The thermodynamic study showed that the biosorption process was spontaneous and exothermic in nature.
The ability of fungal waste biomass type White Agaricus Bisporus to biosorb Pb(II) ,Cr(III), Cd(II) and Co(II) from wastewater was investigated in batch process. Single and binary mixtures were used at low metal concentration wastewater treatment. The size of the biosorbent ranged 0.3-1 mm. The biosorption capacity of the biosorbent was evaluated under equilibrium conditions at 25 °C. Results indicated that the biosorption capacity of waste of fungi for the binary mixture was always lower than that for a single component system. Eight isotherm models were used to fit the experimental data of single system and Langmuir model was found a suitable to describe the biosorption data. The maximum uptake capacity (qe) of Pb(II), Cr(III), Cd(II) and Co(II) in single system was 158.73, 46.94, 40.16 and15.94 mg/g respectively with correlation coefficients 0.999,0.998,0.988 and 0.991 respectively. For binary system, four biosorption models were used to fit the experimental data. Extended Langmuir model gave the best fitting. The removal percentage of heavy metals onto fungal waste biomass was in order of Pb(II) > Cr(III) > Cd(II) > Co(II) in both single and binary system. The results show that the using waste of fungi as a biosorbent of heavy metals gave a higher uptake capacity of four heavy metals.