Kinetic Adsorption of Heavy Metal (Copper) On Rubber (Hevea Brasiliensis) Leaf Powder

Abstract

This research was carried out to study the adsorption of copper from aqueous solution onto rubber leaves powder (RLP) using a batch adsorption process. The functional groups responsible for the adsorption of copper onto the rubber leaves surface were investigated using the Fourier Transform Infra-red (FTIR). Factors influencing adsorption, for example, contact time, adsorbent dosage, pH, copper concentration, particle size, and temperature were also studied. The maximum Cu (II) ions adsorption was observed to have occurred at a pH of 5. The adsorption capacity of Cu (II) ions reduced as the particle size and adsorbent dose increased. The Kinetic studies showed a good correlation and best matched the kinetic model of a pseudo-second order. The Freundlich and Langmuir isotherm models were used to describe the Cu (II) adsorption onto the rubber leaves powder. The data gotten from the adsorption process were best compliant with the Langmuir model with a correlation value of 0.9912 and a maximum adsorption capacity of 9.074 mg / g. The thermodynamic variables (parameters) like entropy change (∆S°), Gibbs-free energy change (∆G°) and enthalpy change (∆H°) were determined and the adsorption process was observed to be an exothermic and a spontaneous process. The adsorption of copper ions from aqueous solution using rubber leaves power involved physisorption mechanism.

Keywords

• Adsorption
• Copper
• Isotherm
• Kinetic
• Rubber leaf powder