Preparation and characterization of composite anthill-chicken eggshell adsorbent: Optimization study on heavy metals adsorption using response surface methodology

Abstract

Background and Objective: The generation of wastewater containing heavy metals has become an issue as their release into the environment has increased as a result of industrialization. This wastewater contains amounts of heavy metals that are harmful to human beings and aquatic species. This present study was aimed to develop mixed anthill-chicken eggshell as composite adsorbent and use to remove heavy metals contained in an aqueous solution via adsorption process. Materials and Methods: The stock solution was prepared by dissolving desired amount of Cu(II) and Zn(II) nitrate in a known volume of deionized water. After preparation of anthill and eggshell powders, the mixed anthill-eggshell preparation conditions were optimized by maximizing the heavy metals uptakes using Central Composite Design (CCD) of response surface methodology (RSM) in design expert 7.0.0 as an optimization tool. The fitness of the developed models was evaluated by analysis of variance (ANOVA-Type III). Results: Findings revealed that the predicted Cu(II) and Zn(II) ions uptakes from the two suggested models agreed reasonably well with the experimental values. The obtained data showed that at 863.78EC calcination temperature, 4 h calcination time and eggshell/anthill mixing ratio of 1.86, the percentages of Cu(II) and Zn(II) ions removed from aqueous solution by optimal composite anthill-eggshell adsorbent were 97.89 and 99.34% respectively. Conclusion: The analyses results revealed that composite anthill-eggshell adsorbent was porous, possessed active functional groups on its surface and made up of active mixed metal oxides with close interaction.