Author ORCID Identifier

https://orcid.org/0000-0002-1623-080X

Date of Award

6-5-2025

Document Type

Thesis

School

School of Civil Engineering

Programme

Ph.D.-Doctoral of Philosophy

First Advisor

Dr.Gautham B Jegadeesan

Keywords

Fe - Fe/Ni, Adsorption, Chromium, Uranium, Dye

Abstract

Access to clean water is a quality-of-life indicator. The availability of clean water apart from water scarcity is marred due to contamination by heavy metals and synthetic dyes, posing a grave environmental and public health challenge. This necessitates the implementation of advanced and sustainable treatment solutions towards water remediation. This research work focusses on the fabrication and application of biogenic and chemically synthesized metallic and bimetallic nanoparticles for the efficient removal of uranium, chromium, and toxic dyes from aqueous environments. The study particularly focuses on zero-valent (C-Fe and B-Fe) and bimetallic (C-NiFe and B-NiFe) nanoparticles, evaluating their adsorption capabilities and degradation efficiencies in treating contaminated water.

Conventional water treatment techniques, such as chemical precipitation, solid-phase extraction, ion exchange and membrane separation, often face limitations due to high operational costs and interference from competing ions. In response, this research investigates an innovative approach—nanoparticle-based remediation—leveraging both chemical reductions using sodium borohydride (for C-Fe and C-NiFe) and eco-friendly biogenic synthesis employing plant extracts (for B-Fe and B-NiFe).

Characterization through X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) confirms structural and morphological integrity of the synthesized nanoparticles. Experimental studies assess the adsorption efficiency of these nanoparticles under varying pH, contaminant concentrations, and adsorbent loadings. The results demonstrate the remarkable potential of biogenic nanoparticles, achieving 99.7% uranium removal at an initial concentration of 500 μg/L and an optimal pH of 7.0. Chromium removal efficiency reaches 95.5% at 100 mg/L, highlighting the effectiveness of both biogenic and chemically synthesized nanoparticles in mitigating heavy metal pollution.

Furthermore, the study addresses the degradation of Congo Red, a hazardous azo dye, utilizing advanced oxidation processes (AOPs). The findings reveal that biogenic nanoparticles facilitate over 90% dye removal, with a peak efficiency of 92.3% at 50 mg/L within 60 minutes. Kinetic studies further elucidate the adsorption mechanisms, showing rapid contaminant removal, with equilibrium achieved within 30 minutes for uranium and 45 minutes for chromium. The research underscores the significance of optimizing process parameters to enhance nanoparticle performance and maximize contaminant removal.

Overall, this thesis contributes to the advancement of environmentally sustainable water treatment technologies by demonstrating the superior performance of biogenic (B-Fe and B-NiFe) and chemically synthesized (C-Fe and C-NiFe) nanoparticles. The findings advocate for continued research into scalable applications of these materials, reinforcing their potential as viable alternatives to conventional water treatment methods for addressing global water pollution challenges.

Download

Share

COinS