J.C.  Igwe, A.A.  Abia, C.Y.  Abasi, 
    Adsorption of Iron (III), Lead (II) and Cadmium (II) Ions by Unmodified Raphia Palm (<I>Raphia hookeri</I>) Fruit Endocarp,
    Environmental Research Journal,
    Volume 5,Issue 3,
    2011,
    Pages 104-113,
    ISSN 1994-5396,
    erj.2011.104.113,
    (https://makhillpublications.co/view-article.php?doi=erj.2011.104.113)
    Abstract: The efficiency of using Raphia palm fruit endocarp (nut) to adsorb metal ions from aqueous solution was studied in a batch system using Atomic Absorption Spectrometry (AAS). Equilibrium adsorption isotherms and thermodynamics studies were carried out. The influence of initial metal ion concentration, temperature and particle size was investigated and the results showed that particle size and temperature affected the sorption rate and that the adsorption was fast with a maximum percentage adsorption of 98.7% in 20 min as initial metal ion concentration was increased. Four isotherms; Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin were used to model the equilibrium sorption experimental data. Also, a normalized standard deviation, &#916;q was used to compare the validity of the isotherm models. The sorption process was found to follow chemisorption mechanism. Thermodynamic parameters were evaluated for the sorption experimental studies. Therefore, these experiments showed that Raphia palm fruit endocarp can be effectively used for the removal of iron (III) and lead (II) ions from dilute solutions.
    Keywords: mechanism;isotherms;metal ions;adsorption;Raphia palm fruit;Nigeria