Enhanced Adsorptive Removal of Dyes Using Mandarin Peel Biochars via Chemical Activation with NH4Cl and ZnCl2

초록

This study examined differences in the adsorption kinetics, isotherms, and thermodynamics of the dyes (methyl orange and fast green FCF) by pristine (M-biochar) and chemical activated mandarin peel biochars (MN-biochar and MZ-biochar). The specific surface area (1085.0 m(2)/g) and pore volume (0.194 cm(3)/g) of MZ-biochar much higher than those of the M-biochar (specific surface area = 8.5 m(2)/g, pore volume = 0.016 cm(3)/g) and MN-biochar (specific surface area = 181.1 m(2)/g, pore volume = 0.031 cm(3)/g). The equilibrium adsorption capacities (mg/g) of MO and FG using M-biochar (MO = 0.95, FG = 0.78) MN-biochar (MO = 2.52, FG = 2.13), and MZ-biochar (MO = 16.27, FG = 12.44) have well-matched the pseudo-second-order model (R-2 >= 0.952) compared with the pseudo-first-order model (R-2 >= 0.008). Furthermore, the better explanation of the adsorption behavior of dyes by the Freundlich isotherm model (R-2 >= 0.978) than the Langmuir isotherm model (R-2 >= 0.881) supports the assumption that the multilayer adsorption governed the adsorption of dyes using mandarin peel biochars. The adsorptions of dyes were significantly dependent on the solution pH and temperature since the electrostatic and spontaneous endothermic reactions governed their removal using the pristine and chemical activated mandarin peel biochars.

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