Diffusion-Chemisorption and Pseudo-Second Order Kinetic Models for Heavy Metal Removal from Aqueous Solutions Using Modified and Unmodified Oil Palm Fruit Fibre

Aims: To investigate the kinetics of Cu(II), Pb(II), Ni(II) and Sn(II) absorption from aqueous solution using modified and unmodified oil palm fruit fibre using diffusion-chemisorption and pseudo-second order kinetic models.

Study Design: The use of oil palm fruit fibre as absorbent for heavy metals absorption from aqueous solution.

Place and Duration of Study: Physical Chemistry Laboratory, Department of Pure and Industrial Chemistry, Abia State University, Uturu, Abia State, Nigeria. The duration was about six (6) months.

Methodology: Majorly, instrumental methodology was used for the detection of the heavy metals. Batch absorption experiment for Cu(II), Pb(II), Ni(II) and Sn(II) were carried out for each absorbent (UOPF, 0.5MOPF and 1.0MOPF). Filtrations were done using whatman no 41-filter paper. The filtrate of each metal solution was analyzed using Shumadzu model 6650 Atomic Absorption Spectrophotometer.

Results: The results showed that chemical modification of the absorbent increased its absorption efficiency which followed the sequence; 1.0MOPF > 0.5MOPF > UOPF. The results also showed that Ni(II) was more removed than the other metals using the three absorbents. Diffusion-chemisorption and pseudo second order kinetic equations were used to model the sorption experimental data. The pseudo-second order model gave better fit to the sorption studies. This implies that the sorption process was of chemisorption mechanism. The initial sorption rate (ho) was higher for Ni (II) ions with values of 0.484, 3.675 and 2.964 for UOPF, 0.5MOPF and 1.0MOPF respectively, and lowest for Sn (II) with values of 0.035, 0.111 and 0.828 for UOPF, 0.5MOPF and 1.0MOPF respectively.

Conclusion: The results of this study showed that oil palm fruit fibre can be efficiently used as a low-cost alternative for the removal of Cu(II), Pb(II), Ni(II) and Sn(II) from aqueous solutions.