This work investigates the fabrication, characterization and testing of Opuntia ficus-indica mucilage nanofibers to be utilized in water filtration systems. These mucilage nanofibers are formed using different polymers through a process called electrospinning. The polymers used to promote the formation of nanofibers are poly vinyl alcohol (PVA) and polystyrene (PS). The mucilage is a jelly like substance extracted from the pads of the cactus plant. It is a mixture of proteins, complex polysaccharides and monosaccharaides. It is an inexpensive, non-toxic, biodegradable and biocompatible material which is present in abundance. The mucilage extracted from the pads is mixed with acetic acid to form the mucilage solution. The mucilage solution is then mixed by volume with co-spinning polymers, PVA and PS. PVA is a synthetic polymer that is water-soluble, and this work considers two types of PVA differentiated based upon molecular weight, such as low molecular weight PVA and high molecular weight PVA. Polystyrene is a synthetic polymer extracted from a monomer styrene, and it is inexpensive, biodegradable, and abundant. The polystyrene, in its solid form, is further decomposed using a solvent called D-Limonene. D-Limonene is a biodegradable, non-toxic solvent formed from the citrus extract of orange peelings. The PVA and PS solutions are mixed in several different volume ratios with the mucilage solutions. These solutions were electrospun and consistent nanofibers were obtained using the low molecular weight PVA solutions and the polystyrene solutions. The fibers and polymeric solutions were characterized by scanning electron microscopy (SEM), contact angle measurements, viscosity, and FTIR. Resulting mucilage nanofiber membranes were characterized by atomic fluorescence spectrometry (AFS) filtration testing. In addition, a life cycle analysis using the SimaPro software was performed to understand the environmental impact of solutions used to fabricate the mucilage nanofiber membranes. Characterization results confirm the formation of PVA:mucilage and PS:mucilage nanofibers. Filtration testing of the nanofiber membranes indicates better performance with membranes formed by PS: mucilage solutions as compared to PVA: Mucilage solutions. Overall, this work has shown that natural materials, such as cactus mucilage, can be synthesized with polymeric solutions to form environmentally friendly water filters.

Water is the essential part of every organism and it is also a vital constituent of healthy living and diet. Unfortunately water contamination over the past decade has increased dramatically leading to various diseases. As technology advances, we are detecting many pollutants at smaller levels of concentrations. Arsenic (As) is one of those major pollutants, and Arsenic poisoning is a condition caused due to excess levels of arsenic in the body. The main basis for Arsenic poisoning is from ground water which naturally contains high concentrations of arsenic. A case study from 2007 states that over 137 million people in 70 countries were affected by arsenic poisoning from drinking water [1]. This thesis work is motivated by this study and investigates the fabrication, characterization, and testing of Opuntia ficus-indica mucilage nanofiber membranes formed using a mucilage, polystyrene (PS) and iron oxide (Fe2O3) solution by an electrospinning process. Cactus mucilage is a jelly-like substance, which is extracted from the cactus pad, and is an inexpensive, biodegradable and biocompatible material. It is also an abundant material available in nature. Polystyrene is a synthetic aromatic polymer prepared from monomer styrene. Polystyrene is further dissolved using D-Limonene as a solvent. D-Limonene is a non-toxic solvent and is a citrus extract of orange peelings. In an effort to enhance adsorption capacity for the mucilage nanofiber membranes, iron oxide nanopowder is incorporated into the polymeric solution. A mucilage and polystyrene-iron oxide solution is mixed in different ratios and electrospun to obtain nanofibers. The fibers will be characterized by certain techniques such as Scanning electron microscopy (SEM), contact angle measurements, viscosity and Fourier transform infrared spectroscopy (FTIR). The fibers obtained from mucilage and PS-Fe2O3 will be further tested under Atomic fluorescence spectrometry (AFS) for testing the removal of arsenic from water. Also, a life cycle analysis (LCA) is conducted to evaluate the environmental impacts of the fabrication of the membranes by using SimaPro® software.