Title:Optimization Removal of Cd (II) from Aqueous Solution by Exhausted Kahwa Coffee Biochar under Various Carbonization Parameters
Volume: 18
Issue: 2
Author(s): Nika R. Yanti, Aninda T. Puari*, Rusnam Rusnam and Irriwad Putri
Affiliation:
- Department of Agricultural and Biosystem Engineering, Faculty of Agricultural Technology, Andalas
University, Padang, West Sumatera, 25163, Indonesia
Keywords:
Biosorption, exhausted kahwa coffee, heavy metal, carbonization parameters, Cd (II), pseudosecond- order (PSO).
Abstract:
Introduction: Recently, abundant agricultural solid waste has been utilized as
sustainable biosorbents for removing heavy metals from aqueous solutions. However, the
influence of the carbonization parameters on the specified biosorbent performance has not
been well discussed. In this study, we developed the removal efficiency (RE) of Exhausted
Kahwa Coffee (EKC) as a low-cost and high-efficiency biosorbent for Cd (II) under various
carbonization temperatures (300 – 600°C) and time (1- 4 h).
Methods: The batch biosorption test showed that the EKC biochar with a carbonization
temperature of 500˚C and time of 4 h removed 97% of Cd (II) from the solution. The biosorption
performance was further investigated by integrating the physicochemical changes
in the surface and functional groups of the EKC biochar at different temperatures using
BET, SEM, and FT-IR instruments.
Results: The FT-IR showed alterations in the functional groups, while the BET data and
SEM images demonstrated that the porous surface of the biochar developed as the temperature
increased. Furthermore, the biosorption test data was plotted in the Langmuir and
Freundlich isotherm models, where the Langmuir isotherm model showed the better fit of
EKC biochar. The maximum biosorption capacity of the EKC biochar on Cd (II) was calculated
at 3.41 mg/g by fitting the equilibrium data to Langmuir isotherm equations.
Conclusion: It was found that the kinetic data fitted well with Pseudo-Second-Order (PSO)
with a correlation coefficient of R2 = 0.99. These findings imply the influence of the carbonization
parameter on the potential biosorption of the EKC biochar on Cd (II).