ISSN: 1304-7191 | E-ISSN: 1304-7205
Relational description of an adsorption system based on isotherm, adsorption density, adsorption potential, hopping number and surface coverage
1Chemical Eng. Department, Nnamdi Azikiwe University, Awka, NIGERIA
Sigma J Eng Nat Sci 2020; 38(3): 1073-1098
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Abstract

Gossweilerdendron balsamiferum (Tola wood) dust, as a precursor was used for the production of acid-activated carbon (TDAC) employed in the adsorptive removal of Cu2+ and Pb2+ ions. The relational adsorptive behaviour of TDAC, equilibrium studies and statistical evaluation of the data prediction performance of the respective models were conducted. The adsorbent was characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. Removal efficiencies of 75.66 % (for Cu-loaded TDAC) and 72.22 % (for Pb-loaded TDAC) were recorded at optimum pH (pH 6.0). The values of adsorption density, adsorption potential, hopping number and surface coverage were 7.256E-13 mol/L; -4920.78 J/mol; 8.44; 0.86 and 9.623E-13 mol/L; -5648.6 J/mol; 8.53; 0.86, for Cu- and Pb-loaded TDAC, respectively. Modified Langmuir model emerged as the best fit model for both adsorption system, as it depicted the lowest average error values of 1.8E-11 (for Cu-loaded TDAC) and 1.43E-12 (for Pb-loaded TDAC). Furthermore, model prediction performance showed that 5-parameter equation with t- and p-values of -0.862; 0.439 (for Cu-loaded TDAC) and -0.804; 0.466 (for Pb-loaded TDAC), was the least predictive among the isotherm models. The study demonstrated the effective application of TDAC in Cu2+ and Pb2+ adsorption, with the Cu-loaded TDAC being more efficient.