area of the active carbon exceeded that of the modified rice
husk.
The equilibrium adsorptions by the RH-g-PMANa, qe
exceeded those of the unmodified rice husk by a factor of
3.0–8.6, indicating that MAA modification substantially
increased the adsorption capacity of the rice husk. The
amounts of adsorbed paraquat at equilibrium increased
with the grafting percentage of MAA in all adsorption
experiments, because more carboxylic acid groups
anchored in the modified rice husk were associated with a
larger grafting percentag