Eco-friendly chitin-MnO2-alginate nanobiocomposite spheres for enhanced heavy metal removal from wastewater

This study investigates a sustainable solution to heavy metal removal from water, addressing critical environmental and health concerns through the use of chitin-MnO2-alginate (Alg/CN-MnO2) nanobiocomposite spheres as high-efficiency adsorbents. Characterization techniques (SEM-EDS, XRD, FTIR) confirmed the composite's suitability for Cd(II) and Pb(II) adsorption, identifying functional groups crucial for metal binding and a predominantly negative surface charge (pHpzc= 3.6) optimal for cation adsorption. Adsorption data best aligned with the Langmuir model, showing maximum capacities of 519.2 mg/g for Cd(II) and 575.6 mg/g for Pb(II), with rapid adsorption and favorable intra-particle diffusion rates for Pb(II) over Cd(II). Column tests demonstrated removal efficiencies up to 74.2 % for Cd(II) and 84.9 % for Pb(II) at optimized flow rates, revealing the composite's robust performance in complex systems. Thermodynamic analysis indicated that the adsorption process is spontaneous and endothermic, supporting its application in real-world conditions. These findings position Alg/ CN-Mn nanobiocomposite spheres as a promising, eco-friendly solution with high potential for scalable, sustainable wastewater treatment, contributing to environmental remediation and public health protection.