Date of Award
Master of Science in Biological and Environmental Sciences (MSBES)
Environmental and Earth Sciences
Soni M. Pradhanang
The increasing negative effects from anthropogenic activities has given rise for bioprospecting new and advanced materials intended for sustainable remediation and restoration efforts. There are currently efforts into exploring naturally found porous substrates to use in a variety of applications, however the cost and availability has been a limiting factor in introducing these into current practices. Many studies have explored and identified the high performance of granulated activated charcoal for water filtration but tend to disregard the environmentally harmful nuances that occur during the manufacturing process. Priority for these porous substrates focus on results, with little to no regard for environmental sustainability. In the case of this research, efforts were made to develop a low-cost, and widely applicable method for utilizing naturally occurring porous media in the form of crushed Quahog seashells for water treatment operations. Emphasis was put on using a porous media that is found naturally worldwide and simultaneously acts as a carbon sink instead of releasing carbon into the atmosphere such as is the case with activated charcoal. This study focused on exploring the versatility of different water treatment situations to show the wide range of potential applications seashells can offer in place of, or in combination with, granulated activated charcoal through chloride-based saltwater remediation and nitrogenous water scenarios. Efforts were made using bench-top water treatment system with different porous substrates, coupled with ICP-AES and ICS analytics. Results show that this method of substrate preparation is capable of producing a 99.2% pure amorphous calcium carbonate substrate (Yoon et al. 2003) (with pore sizes visible up to 2 nm in size, suggesting that Quahog shells could be a viable sorbent source for a wide range of different pollutants and analytes. Porosity values of crushed Quahog shells as a sediment has been observed between 49-67% (Pfeiffer & Rusch. 2000). To perform the analysis of CaCO3 in the water treatment study, anion quantification was conducted with an Ion Chromatography System (ICS-5000), and cation analysis was done by an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). Results from the water treatment section show that amorphous calcium carbonate (ACC) did not remove as much chloride-based road salts as activated charcoal did but removed more than gravel and sand. Additionally, with each column that contained shells, calcium was released into the collection containers indicating potential environmental benefits for organisms that rely on calcium for growth when shells are used in combination with road salts for deicing practices. During deicing of roadways, cations are depleted from the environment neglecting plants and organisms relying on those nutrients for growth (Kelting & Laxson, 2021.) When treating with nitrogenous waters, again activated charcoal was the top remediator, however ACC was able to remove up to 4x as much phosphate as did the gravel and sand. All results from this research will supplement the science of previous amorphous calcium carbonate water treatment studies, as well as promote the growth of aquacultures and bivalves for environmental sustainability.
McCarron, Brendan, "POTENTIAL APPLICATIONS OF AMORPHOUS CALCIUM CARBONATE (ACC) IN WATER TREATMENT OPERATIONS" (2023). Open Access Master's Theses. Paper 2329.