Among the four isotherm models, both Freundlich and Temkin models were
fitted with the equilibrium
isotherm for copper, while Temkin and Dubinin–Radushkevich models best correlated for nickel and
Langmuir isotherm model best describe the experimental data for chromium. The adsorption capacity for
each studied heavy metals is reported as follows: copper qe = 6.07 mg Cu/g MAG, nickel qe = 5.53 mg Ni/g
MAG and chromium qe = 5.497 mg Cr/g MAG with a removal percentage of 90%, 68% and 91%, respectively
for each ion at 1 g dose of biosorbent. Results also show that MAG pods are not a good biosorbent for the
removal of zinc from wastewater. Kinetics results were best described by pseudo-second order model for
all metals