Date of Award

5-28-2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

Anindya Ghosh

Abstract

Nitrophenols (NPs) and their derivatives are highly toxic, mutagenic, and bio-refractory pollutants commonly present in natural water resources and industrial wastewater. Various types of materials and methods have been practiced removing the NPs from polluted water. In this research, we are focusing on synthesizing of inexpensive doped carbon-based materials using renewable and biodegradable polymers such as microcrystalline cellulose and nanocrystalline cellulose. Current work has been undertaken to develop doped carbon-based materials using a low-cost and straightforward method and characterized using different analytical techniques. The synthesized materials were used for the sustainable and efficient removal of NPs from an aqueous environment using two different techniques, such as adsorption and photocatalytic degradation. The adsorption experiments were performed by varying different parameters. The kinetics studies revealed that adsorption of 4-NP better fitted pseudo-second-order kinetics model. The adsorption isotherm studies showed that the adsorption 4-NP followed both Langmuir and Freundlich adsorption. Similarly, the data on photocatalytic degradation of NPs showed that prepared doped carbon-based material was visible light active and maintained its catalytic activity for multiple cycles. From the kinetics studies, it was observed that the degradation of 4-NP followed the first-order kinetics. Fitting of both Langmuir adsorption isotherm and Langmuir-Hinshelwood (L-H) kinetics model suggested that the adsorption of 4-NP on the photocatalyst occurred before their degradation. The degradation of 4-NP into its intermediates and the mineralized products were established through the GC-MS, ion-chromatography, and total organic carbon (TOC) techniques. Similarly, radical quenching experiments facilitated to propose a possible mechanism of NPs degradation.

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