Microwave-assisted urea modified crop residue in Cu²⁺ scavenging

Raphia hookeri fruit epicarp (RHFE) was used in a novel adsorbent preparation via a combination of urea modification and microwave irradiation. The prepared adsorbent (URHFE) was characterized physicochemically, spectroscopically and microscopically characterized. URHFE efficiency in Cu²⁺ scavenging was tested with focus on operational parameters such as pH, dosage, concentration, contact time, ionic strength and temperature. Adsorption data were tested with isotherms and kinetics models. Optimum adsorption occurred at pH of 5.5. The presence of competing ion decreased Cu²⁺ removal and this varied with competing ion concentration. Cu²⁺ uptake decreased with increase in temperature. Percentage desorption was found generally low. The Langmuir monolayer adsorption capacity (q_max) was obtained to be 144.93 mg/g, this compared well in effectiveness with other adsorbent previously reported. Dubinin Radushkevich (D-R) isotherm model suggests that adsorption mechanism was chemical in nature. Pseudo second order kinetics best described the adsorption kinetics while multilinear adsorption was observed from the intraparticle diffusion model.