Document Type

Honors Thesis

Publication Date

Spring 2019

Abstract

Arsenic, a metalloid, is one of the most prominent toxins in Maine drinking water. There are approximately 86,500 Maine citizens exposed to water containing arsenic over the maximum contamination level causing adverse effects including nausea, multiple cancers, and a reduction of full scale IQ and executive function. In drinking water, arsenic arises both by the natural leaching from bedrock and from the use of chemicals such as pesticides, embalming fluids, and wood preservatives. Although there are many known arsenic water remediation techniques, finding a method compatible for multiple arsenic isotopes is challenging. In this work, we test the low-energy and low-cost technique coupling ferric chloride pre-treatment coagulation with liquid-gated membrane filtration. We find that flocs are formed under specific conditions and can be filtered out of the water, bringing the arsenic with it. We were additionally able to determine the size of these particles using dynamic light scattering and associated pH changes during pre-treatment steps. This work provides evidence that liquid-gated membrane filtration can be used to effectively filter out arsenic containing flocs. These experiments lay the groundwork for a new approach to arsenic remediation of Maine drinking water using membrane filtration, in a low-cost, self-cleaning system.

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