Abstract: Batch assays of litchi pericarps adsorbing malachite green (MG) in water were conducted were conducted for exploring its influencing factors, such as dosage of adsorbent, pH and duration of exposure, adsorption isotherm, kinetics and thermodynamics, and its mechanism as well. Results show that the optimal dosage of adsorbent for raw litchi pericarps (RLP) and modified litchi pericarps (MLP) adsorbing malachite green was 4 and 2 g•L^-1, respectively, the optimal pH, 7.0, and adsorption equilibrium time, 120 min. The adsorption processes of both RLP and MLP could be well described with the Langmuir and Freundlich isothermal models, and they fitted the pseudo-second-order dynamic model. The maximum MG adsorption capacities of RLP and MLP is 72.46 and 169.49 mg•g^-1, respectively. Additionally, results of the thermodynamics tests suggest that the MG adsorption processes by RLP and MLP are both spontaneous endothermic ones.

Key words: litchi pericarp, malachite green, adsorption, capacity, mechanism