Award Date

5-1-2021

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Water Resource Management

First Committee Member

Erick R. Bandala

Second Committee Member

Jaeyun Moon

Third Committee Member

David Kreamer

Fourth Committee Member

Michael Wells

Number of Pages

62

Abstract

Zero-valent iron nanoparticles (nZVI) have been studied as an option for soil remediation and water treatment for many years. The capability of nZVI to produce oxidation/reduction processes, depending on the reaction conditions, has attracted great interest with their major drawback being reactivity loss through agglomeration. The loss in nZVI surface area has been reported to be prevented through immobilization onto a porous media (e.g., SBA-15, MCM-41, or zeolites). In this work, a mesoporous silica structure (SBA-15) is used as an nZVI supporting material to enhance its reactivity and promote peroxymonosulfate (PMS) catalytic decomposition for the degradation of antibiotics in aqueous phase through advanced oxidation processes (AOPs). The reactivity of the immobilized nZVI nanoparticles on SBA-15 (nZVI/SBA-15) for PMS decomposition and the potential of the nZVI/SBA-15/PMS system to degrade antibiotics (e.g., sulfamethoxazole, tetracycline and amoxicillin) was tested using three different nZVI/SBA-15 dosages (0.5, 1.0, and 1.5 g L-1) and two different PMS dosages (5, and 1.25 mmol L-1 ). The reactivity of the system using the different conditions tested was measured for hydroxyl radical production using a well- known free radical scavenger (p-nitroso-dimethylamine, pNDA) using UV-visible spectroscopy. The degradation curves for PMS and antibiotic concentrations were recorded using high performance liquid chromatography (HPLC) with a diode array detector. Samples were collected at approximately 5 min intervals with preliminary data showing a degradation rate > 97% using 1.5 g L-1 of nZVI/SBA-15 and 5 mmol L-1 PMS with a total reaction time of 30 min for sulfamethoxazole (SMX), 89.8% degradation using 0.5 g L -1 nZVI/SBA-15 and 1.25 mmol L-1 PMS of tetracycline (Tetra), and 63.9% using 1.0 g L-1 nZVI/SBA-15 and 5 mmol L-1 PMS of amoxicillin (AMX). It was observed that when lower nZVI/SBA-15 doses were used for the same concentration with PMS, the main reaction occurred within the first 5 min of the reaction. The same was observed when PMS was run alone (without nZVI/SBA-15). When high nZVI/SBA-15 doses, were used the initial reaction rate was found to be reduced suggesting different mechanisms for the degradation process might be at play. The nZVI/SBA-15/PMS system was found to be a highly interesting alternative for the removal of antibiotics in water.

Keywords

Advanced Oxidation Processes; Antibiotics; Catalysis; Fenton-like reactions; Nanomaterial Composites

Disciplines

Chemical Engineering | Nanoscience and Nanotechnology | Water Resource Management

File Format

pdf

File Size

1570 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Download


Share

COinS