Abstract:
The discharge of industrial wastewater containing toxic metals like Pb(II) and Cd(II) has raised concerns about pollution and health hazards. These contaminants, commonly originating from mining, battery manufacturing, electroplating, steel production, and explosives industries, often exceed safe limits due to inefficient treatment technologies.
Nanoparticle-based adsorbents are increasingly used for the mitigation of heavy metals owing to their exceptionally high surface area and reactivity. However, their scalability is hindered by potential leaching, posing obstacles to widespread implementation. Hence, the first part of this work investigates spherical hydroxyapatite nanoparticles (SHAP) and the impact of Mg doping in SHAP (Mg-SHAP) on enhancing the efficiency for the uptake of Pb(II) and Cd(II) from water. In the second part, a compact, reusable, and scalable alternative to conventional adsorbents was developed by immobilizing the most effective Mg-doped SHAP formulation onto a fabric substrate. This approach not only simplifies recovery of the adsorbent but also minimizes environmental risks owing to the possible leaching of nanoparticles, making it well-suited for real-world wastewater treatment applications.
Mg-SHAP has been synthesized with varying doping percentages (5, 10, 20, 30 %) through a facile coprecipitation method. State-of-the-art characterizations revealed defects in the SHAP lattice and a reduction in nanoparticle size from 27.5 nm for SHAP to 12.5 nm after Mg doping (10%). These alterations in the structure resulted in a significant enhancement in the adsorption capacity from 288 to 1942 mg/g for Pb(II) and 106 to 257 mg/g for Cd(II) by using SHAP with 10% Mg doping (10Mg-SHAP), over SHAP. Further, an enhanced rate of Pb(II) and Cd(II) removal was obtained using 10Mg-SHAP as compared to SHAP. The enhancement in the uptake efficacies can be attributed to smaller sizes of 10Mg-SHAP, lattice defects and greater amorphous nature.
Consequently, the optimal 10Mg-SHAP was selected and impregnated onto KMnO?- treated nylon-6 fabric through an in-situ deposition method. The surface morphology before and after impregnation was examined using SEM, which confirmed a uniform distribution of nanoparticles across the fabric surface. To evaluate the performance of 10Mg-SHAP on the fabric surface, batch adsorption using the composite has been performed, revealing a maximum adsorption capacity equivalent to 86 and 18 mg/g for Pb(II) and Cd(II), respectively.
Subsequently, to investigate the practical applicability of the composite towards industrial wastewater treatment, the batch process has been translated to a continuous lab-scale process. The composite showed an excellent reduction of Pb(II) and Cd(II) concentrations from an initial concentration of 10 ppm, achieving levels below the permissible discharge limits of
0.1 ppm for Pb and 1 ppm for Cd. Thus, this research aims to propose an efficient wastewater treatment technique to ensure clean and safe water, aligning with the Sustainable Development Goals for clean water, industry, and innovation.
Biography:
Yashvi Sheth is a Ph.D. student at the Centre for Research in Nanotechnology and Science (CRNTS), Indian Institute of Technology Bombay, under the supervision of Prof. Rajdip Bandyopadhyaya (Department of Chemical Engineering) and Prof. Amritanshu Shriwastav (Environmental Science and Engineering Department). She holds a B.Tech and M.Tech in Chemical Engineering. Her research focuses on the development of nanocomposite materials for the efficient removal of heavy metals from wastewater.
Copyright 2024 Mathews International LLC All Rights Reserved
