Resumo

BELHAMDI, Badreddine; MERZOUGUI, Zoulikha; TRARI, Mohamed  e  ADDOUN, Abdelhamid. A kinetic, equilibrium and thermodynamic study of L-phenylalanine adsorption using activated carbon based on agricultural waste (date stones). J. appl. res. technol [online]. 2016, vol.14, n.5, pp.354-366. ISSN 2448-6736.  https://doi.org/10.1016/j.jart.2016.08.004.

The main purpose of this work is to produce low cost activated carbons from date stones wastes for the adsorption of L-phenylalanine. The activated carbons were prepared by chemical activation with KOH (ACK) and ZnCl2 (ACZ) and characterized by scanning electron microscopy, N2 adsorption-desorption isotherms and FT-IR spectroscopy. Both The activated carbons ACK and ACZ have high specific surface areas and large pore volumes, favorable for the adsorption. Batch experiments were conducted to determine the adsorption capacities. A Strong dependence of the adsorption capacity on pH was observed, the capacity decreases with increasing pH up to optimal value of 5.7. The adsorption follows a pseudo-second order kinetic model. Additionally, the equilibrium adsorption data were well fitted to the Langmuir isotherm, and the maximum adsorption capacities of L-phenylalanine onto ACK and ACZ were 188.3 and 133.3 mg g−1 at pH 5.7, respectively. The thermodynamic study revealed that the adsorption of L-phenylalanine onto activated carbons was exothermic in nature. The proposed adsorption mechanisms take into account the hydrophobic and electrostatic interactions which played the critical roles in the L-phenylalanine adsorption.

Palavras-chave : Activated carbon; l-phenylalanine; Size distribution; Sorbent surface; Adsorption isotherm; Thermodynamic.

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