Background: There are different types of pollutants in water hence they are constantly in
competition for active sites during the adsorption process. A key advantage of competitive adsorption
studies is that these inform regarding the adsorbent’s performance in real water treatment applications.
Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and
Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE.
Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and
Fourier Transform Infrared Spectroscopy (FTIR). The adsorption parameters, equilibrium isotherm
modelling and parametric studies were conducted based on data from the batch adsorption experiments.
Results: For both adsorbents, the removal efficiency was >99% over the entire investigation for
dosage and contact time, suggesting that they are very efficient for removing multiple heavy metals
from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact
time was 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second
order kinetic models were best-fit for the competitive adsorption process.
Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass
and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy
metals from aqueous media. This study bears a positive implication for environmental protection
and solid waste management.