Fuente: Sustainability - Revista científica (MDPI) Sustainability, Vol. 18, Pages 612: Purple Ipe Leaf as a Sustainable Biosorbent for the Removal of Co(II) and Cd(II) Ions from Aqueous Samples
Sustainability doi: 10.3390/su18020612
Authors:
Bárbara Poso Gregnanin
Toncler da Silva
Marcos Vinícius Nunes Filipovitch Molina
Adrielli Cristina Peres da Silva
Diego Rafael Nespeque Corrêa
Margarida Juri Saeki
José Fábian Schneider
Valber de Albuquerque Pedrosa
Marco Antonio Utrera Martines
Gustavo Rocha de Castro

The increasing contamination of water resources by wastewater has stimulated extensive research into advanced methods for effluent analysis, monitoring, and treatment. Heavy metals are among the most concerning pollutants due to their toxicity, persistence, and potential for bioaccumulation and biomagnification in living organisms. This study investigates the use of purple ipe (Handroanthus impetiginosus) leaves as a biosorbent for the removal of Co(II) and Cd(II) ions from aqueous solutions. The biosorbent was characterized using FTIR, NMR, EDX, SEM, and elemental analysis, revealing a porous and heterogeneous surface with functional groups suitable for metal adsorption. The point of zero charge (pHPZC) was 5.8, and the zeta potential was −14.7 mV, indicating a negatively charged surface at higher pH values. Maximum removal efficiency was observed in the pH range of 5–6. Kinetic data showed the best fit to a pseudo-second order model, while adsorption equilibrium was most accurately described by the Langmuir isotherm, suggesting a monolayer adsorption process. The maximum adsorption capacities were 0.823 mmol g−1 for Co(II) and 0.270 mmol g−1 for Cd(II). The results demonstrate that purple ipe leaves are a sustainable, efficient, and low-cost biosorbent for wastewater treatment, showing great potential for mitigating environmental impacts associated with heavy metal pollution.