Adsorption of Lead and Cadmium in Aqueous Solution onto Oil-Palm Solid Wastes, Bentonite and Amberlite Polymeric Adsorbents

The adsorption of heavy metals ion (Pb2+ and Cd2+) onto three types of adsorbents;
bentonite, oil-palm solid waste and Amberlite XAD polymeric adsorbents is described in
this report. The studies were done in batch, as the samples were mixed with a dosage of
2.5g/l of each adsorbent and shake at 150rpm until it reaches equilibrium. Kinetics
studies show that bentonite is the best adsorbent, while oil-palm solid waste and
Amberlite XAD polymeric adsorbents are comparable. The adsorption isotherm
parameters were calculated and fitted into Langmuir isotherm and Freundlich isotherm.
All adsorption can be described by Freudlich isotherm with the highest degree of fit of
lead on OPEFB (0.954) and cadmium on XAD16 (0.99). The effect of pH is examined
over the range of 1-5.5. The adsorption of Pb2+ and Cd2+ increase with increasing pH and
bentonite was highly affected by the increment. Finally, the adsorbents were analyzed by
using FTIR to get the infrared spectra, and the functional groups were determined while,
the infrared spectra for Amberlite XAD polymeric adsorbents were acquired from
product data sheets.