Life Cycle Assessment of the Decomposition of Perfluorooctanoic Acid in Water Using Three Environmentally Friendly Technologies

Perfluorooctanoic Acid (PFOA) is the most important derivative of the Perfluorinated Compounds (PFCs). It is an unnatural compound that appears in the environment as a result of human production processes. PFOA is used extensively in the manufacturing of fluoropolymers and a wide range of industrial products such as surfactants, fire retardants, as well as oil, stain and grease repellants. The life cycle of all PFOA related products including producing, using, and discarding, incurs the risk of water, air, and soil pollution, with water pollution being the most prevalent. Factors such as environmental persistence, bioaccumulation, long-range environmental transport issues, and potential toxicity to humans contribute to PFOA as being regarded as a one of the Persistent Organic Pollutants (POPs). Furthermore, PFOA is not easily destroyed by natural processes due to its extreme stability resulting from strong C-F bonds. There are currently a variety of methods for degrading PFOA in the water, however, these treatment processes may all cause direct or indirect impacts to the environment through the addition of chemicals, inefficient energy use, improper waste treatment, and so on. As such, a comprehensive assessment to determine appropriate treatment processes is essential. In this study, the main objective is using Life Cycle Assessment (LCA) to compare the environmental impacts of three environmentally friendly processes for the decomposition of PFOA from water. The three kinds of technologies are: (1) microwave-induced persulfate, MIPO; (2) sonication-assisted photo-catalytic oxidation, SAPO; and (3) electro-membrane filtration, EMF. Environmental assessments are carried out using SimaPro 7.2 LCA software and utilizing the IMPACT 2002+ methodology to evaluate the potential environmental impact. The results revealed the major causes of environmental impact for Case 1 (MIPO) and Case 2 (SAPO) are both materials preparation, and for Case 3 (EMF) is appling external magnetic field during electro-membrane treatment. The top three environmental impact categories for all three cases are non-renewable energy, global warming, and respiratory inorganics. While choose the functional unit of concentration standard (the concentration of PFOA removed to 30 ppm), the degree of environmental impact is Case 2 (SAPO) > Case 3 (EMF) > Case 1 (MIPO); and under the functional unit of weight (removal of 6.15 mg PFOA), the degree of environmental impact is Case 1 (MIPO) > Case 2 (SAPO) > Case 3 (EMF). Under two different functional units, the key factors are both energy consumption, so improving energy efficiency and reducing energy use are goals to reach in the future. The assessment of these laboratory-scale treatments for degrading PFOA from water will be valuable for real work sites. This may assist in identifying the most environmentally friendly technologies for achieving green chemistry goals, namely the minimization of environmental and health hazards.