Adsorption of lead and chromium ions from electroplating wastewater using plantain stalk modified by amorphous alumina developed from waste cans

E O Ajala; M O Aliyu; M A Ajala; G Mamba; A M Ndana; T S Olatunde

doi:10.1038/s41598-024-56183-2

Adsorption of lead and chromium ions from electroplating wastewater using plantain stalk modified by amorphous alumina developed from waste cans

Sci Rep. 2024 Mar 13;14(1):6055. doi: 10.1038/s41598-024-56183-2.

Authors

E O Ajala¹, M O Aliyu², M A Ajala², G Mamba³, A M Ndana⁴, T S Olatunde⁵

Affiliations

¹ Department of Chemical Engineering, University of Ilorin, Ilorin, Nigeria. ajala.oe@unilorin.edu.ng.
² Department of Chemical Engineering, University of Ilorin, Ilorin, Nigeria.
³ Institute for Nanotechnology and Water Sustainability, College of Science, Engineering, and Technology, University of South Africa, Florida, Johannesburg, 1709, South Africa.
⁴ Department of Chemical Engineering, Federal Polytechnic, Bida, Nigeria.
⁵ Department of Food Science and Technology, Federal University of Technology, Akure, Nigeria.

Abstract

Waste beneficiation is key to environmental protection and the realisation of a circular economy. Herein, amorphous alumina (a-Al₂O₃) derived from aluminium waste cans (AWC) was used to modify plantain stalk as an adsorbent for sequestration of lead (II) and chromium (VI) ions from electroplating wastewater. Raw plantain-stalk (RPS) and amorphous-alumina modified plantain stalk (APS) developed as adsorbents were characterised using various equipment such as x-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET). The FTIR revealed that the adsorbents are rich in functional groups that could promote the adsorption process which includes carboxyl, hydroxyl, and aliphatic groups. Also, the BET analysis showed a substantial increase in the surface area of APS (174.448 m²/g) compared to that of RPS (40.531 m²/g) which could be due to the effect of modification by the a-Al₂O₃. The batch adsorption studies revealed that the APS achieved 99.38% and 98.33% removal of Cr(VI) and Pb(II), respectively, which is superior to RPS adsorption efficiency. Also, the estimated and experimental data for the APS compared well under all the kinetic models studied with R² > 0.88. This suggested that chemisorption is the most plausible adsorption mechanism of Cr(VI) and Pb(II) onto the APS. Further analysis showed that the Cr(VI) and Pb(II) adsorption followed the Langmuir model with the R_L value of 0.038 and 0.999, respectively, which indicated that the two metal ions were effectively adsorbed onto the APS. Therefore, this work demonstrated that the modification of plantain-stalk with amorphous-alumina derived from AWC enhanced the characteristics of the APS and favoured its adsorption of the selected heavy metals.