Central composite design optimization of copper (ii) ions removal in aqueous solution using azadirachta indica (neem) leaf powder

Abstract

Biosorption is considered as a potential method for the removal of heavy toxic metals from waste solution and as alternative to other conventional process such as precipitation, ion exchange, electrochemical treatment and evaporative recovery, especially, when the concentration of the heavy metal ion is low. In the present study, (Azadirachta indica) neem leaves Powder (NLP), was investigated for the removal of Cu(II) ions from aqueous solution based on modelling and optimization. Central composite design was successfully applied to develop a response surface to optimize medium conditions. Characterisations of the NLP was conducted, and the effects of contact time (0-180 minutes), Cu(II) ion concentration (10
(298-318 K) and dosage (0.52.5 g/L) were studied in batch process. The optimal adsorption of copper obtained was found to be 308 K, 97.5min and 1.5g respectively resulting in 100% of adsorption of copper The analysis with FTIR indicated thyat possible hydroxyl and carboxyl functional groups are involved in metal CU(II) ions biosorption. Adsorption isotherms were modelled by the Langmuir and Freundlich isotherm equations, with the former providing a better fit for the data. Results obtained from this study indicate that NLP is a very promising candidate for the low-cost and high-capacity removal of Cu(II) ions from aqueous solution.