Copper scavenging efficiency of adsorbents prepared from Raphia hookeri fruit waste

Low cost adsorbents prepared from the epicarp of Raphia hookeri fruit were used for the removal of copper (II) ion from aqueous solution. The effects of operational parameters such as pH, concentration and contact time, dosage as well as interference of other ions were studied. Optimum pH for raw and modified biomass were 5.0 and 5.5 with percentage removal of 75.08% and 95.62% respectively. Concentration of competing ions greatly reduced Cu²⁺ removal with both adsorbents while agitation speed had negligible effect on Cu²⁺ uptake. Adsorbents surfaces were activated as temperature increased thus enhancing adsorbent adsorption capacity at high temperature. Adsorption kinetic data fitted best into the pseudo second order model while the thermodynamics studies confirmed adsorption spontaneity and feasibility. The Freundlich adsorption isotherm best described the adsorption process and the Langmuir maximum monolayer adsorption capacity for the raw (RHE) and acid treated (ARHE) biomass were 81.97 and 103.09 mg/g respectively. Chemisorption predominate the Cu²⁺-ARHE system hence desorption efficiency was obtained to be 72.65% with CH₃COOH as eluent.