Vol.:(0123456789) 1 3 Chemistry Africa https://doi.org/10.1007/s42250-019-00113-7 ORIGINAL ARTICLE Adsorption Behaviour of Rhodamine B on Hen Feather and Corn Starch Functionalized with Green Synthesized Silver Nanoparticles (AgNPs) Mediated with Cocoa Pods Extracts Luqmon Azeez 1  · Agbaje Lateef 2  · Ayoade L. Adejumo 1  · Joshua T. Adeleke 3  · Rasheed O. Adetoro 1  · Zainab Mustapha 1 Received: 17 October 2019 / Accepted: 11 December 2019 © The Tunisian Chemical Society and Springer Nature Switzerland AG 2019 Abstract This study reports useful application of biodegradable polymeric materials functionalized with silver nanoparticle (AgNPs) biosynthesized from cocoa pods as efective adsorbent for dye wastewater purifcation. Corn starch and hen feather were functionalized with AgNPs for adsorption of rhodamine B (Rh-B). All adsorbents were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray difraction. Decreased intensities of peaks, superior rougher cavities and smaller grain diameter of functionalized biomaterials afrmed the functionalization. Efects of pH, contact time, initial Rh-B concentrations and temperature were investigated and found to be signifcantly important. Four isotherm models were used to describe the adsorption process with Freundlich being the most suitable for all adsorbents indicating Rh-B adsorbed on heterogeneous multilayer surfaces of adsorbents. AgNPs modifcation greatly enhanced maximum monolayer adsorption capacities (q max ) of feather (4.27–56.53 mg g −1 ) and starch (1.176–48.60 mg g −1 ) by 30- and 40-fold respectively. Kinetic rates of adsorption for starch best ftted Elovich, pseudo frst order for feather whereas pseudo second order best suit- able for starch-AgNPs and feather-AgNPs. Energies (3.89–7.68 kJ mol −1 ) of adsorption suggest that adsorption of Rh-B onto the adsorbents was by physiosorption. The negative values of ∆H° and ∆G° imply that adsorption processes were exothermic and spontaneous. Results in this study show that surface functionalization of starch and feather improved their adsorptive performances and will fnd valuable applications in dye remediation due to their biodegradability and cost-efectiveness. Keywords Feather-AgNPs · Starch-AgNPs · Surface morphology · Surface chemistry · Functionalization 1 Introduction Effluents resulting from applications of dyes in textile, papers, leather, plastics and paints industries have been burdens on ecology and aquatic ecosystems leading to dis- ruption of biological and ecological processes in water such as decreasing dissolved oxygen (DO), increasing chemical oxygen demand (COD), imparting colour, odour and taste which are not desirable. These efuents are non-biodegrad- able, and bio-accumulate with time in aquatic fauna which are eventually consumed by animals and humans. Dye efu- ents are carcinogenic, mutagenic, genotoxic, nephrotoxic, mutagenic, hepatotoxic and prompt allergic reactions [1–4]. Rhodamine B is a synthetic cationic dye belonging to xanthene class. It is basic, highly reactive and fnd appli- cations in textiles, paper, drinks, foods and leather owing solubility in water and excellent fastness. Rh-B has been reported to irritate the skin, eyes, respiratory tracts, induce hormonal disturbances in addition to being neurotoxic and genotoxic. Also, it readily undergoes anaerobic degradation in water producing carcinogenic amines from reductive ami- nation and remediation using conventional and biological methods has not yielded great results due to its complex structure, toxicity and high molecular weight [5–12]. * Luqmon Azeez luqman.azeez@uniosun.edu.ng 1 Department of Pure and Applied Chemistry, Osun State University, Osogbo, Nigeria 2 Nanotechnology Research Group (NANO+), Laboratory of Industrial Microbiology and Nanobiotechnology, Department of Pure and Applied Biology, Ladoke Akintola University of Technology, PMB 4000, Ogbomoso, Nigeria 3 Department of Physical and Mathematical Sciences, Osun State University, Osogbo, Nigeria