TITLE:
Optimization and Thermodynamic Studies of Lead (II) and Cadmium (II) Ions Removal from Water Using Musa acuminate Pseudo-Stem Biochar
AUTHORS:
Daniel Nimusiima, Irene Nalumansi, Paul Mukasa, Denis Byamugisha, Emmanuel Ntambi
KEYWORDS:
Adsorbent, Biochar, Lignocellulose, Heavy Metals, Water Treatment
JOURNAL NAME:
Green and Sustainable Chemistry,
Vol.13 No.4,
November
6,
2023
ABSTRACT: We recently found out that water from the Ugandan stretch of the Kagera
transboundary river (East Africa) is contaminated with lead (Pb2+)
and cadmium (Cd2+) ions at levels that are above permissible limits
in drinking water. Because lignocellulosic biomass-based adsorbents have been
explored for the remediation of metal ions from water, this study investigated
the potential of Musa acuminata pseudo-stem (MAPS) biochar for the
remediation of Pb2+ and Cd2+ ions from water. Batch
adsorption experiments were performed to optimize the adsorption conditions
while the isotherms were analyzed using Freundlich and Langmuir models. Results
showed that the maximum adsorption capacity at equilibrium was 769.23 mg/g and
588.23 mg/g for Pb2+ and Cd2+ ions, respectively.
Langmuir isotherm model provided the best fit for the data, and it was
favorable since all r2 values (Cd2+ = 0.9726 and Pb2+ = 0.9592) were close to unity. Gibb’s free energy change was found to be
negative for both metals, implying the feasibility of the adsorption process.
Correspondingly, the enthalpy change was positive for both metal ions which
revealed that the adsorption process was endothermic and it occurred randomly
at the solid-liquid
interface. These results suggested that biochar from MAPs could be utilized for
the removal of Pb2+ and Cd2+ from polluted water in the
Kagera transboundary river to make it suitable for domestic use. Further
studies should consider chemical modification of the biochar as well as
characterization to examine the chemical nature of the biochar.