Since the 1960's the aquaculture industry has grown enormously and is one of the fastest growing sectors in the food industry. This massive growth has been influenced by changes in diet worldwide as well as improved aquaculture practices that have led to lower production costs and greater yields. In 2020, worldwide aquaculture production reached a remarkable 87.5 million tons, worth USD 265 billion, with a further 15% increase expected by the year 2030. Molluscs, the class of seafood most relevant to this research, play a vital role in the advancement of aquaculture, and accounted for 17.7 million tons, that is, 14% of total aquaculture production. Since a substantial proportion of the entire mollusc is the inedible shell, a considerable quantity of byproduct is generated. This byproduct stream, along with waste generated pre-consumption (i.e. waste from discards of premature or dead catches) consist predominantly of calcium carbonate and can serve as a significant feedstock for low cost, renewable calcium carbonate materials. Many uses of biogenic calcium carbonate from shells have been explored over the years providing valuable alternatives to landfill disposal and sea dumping, which could impact land and marine ecosystems. Such approaches offer a more environmentally benign approach to waste management and promote the concept of a circular economy. Soft calcite (SC) is a material that was previously reported by the Kerton group and was obtained upon treatment of blue mussels (Mytilus edulis), a native species of mussels harvested in Newfoundland and Labrador, with dilute acetic acid. Blue mussel shells consist of two polymorphs of calcium carbonate, namely calcite and aragonite. However, SC made from treated shells consists only of calcite which presents a different morphology from the calcite present in the original shell material. Initial experiments using the SC material showed promise for use as an adsorbent material for wastewater treatment. The potential utilization of the SC as an adsorbent could potentially render wastewater treatment more viable, cost-effective, and readily available, especially for developing nations and rural populations that continue to grapple with water quality concerns. For one, the cost of raw materials and the processing of these for making an adsorbent is oftentimes high, which ultimately results in the cost of the adsorbent being unattractive to industries. In fact the cost of adsorbents can account for almost ¾ the total operational cost of a waste facility. These adsorbents include activated carbon/charcoal, zeolites and bentonites clays. SC could be an economically viable option for the replacement of these 'expensive adsorbents' since waste mussel shells would be obtained at a much reasonable price and their processing would not be costly. Secondly, SC could be a renewable alternative to some unsustainable adsorbents such as petrochemically derived activated carbon materials which have come under scrutiny over the years for its environmental impact. Within this paper, further investigations into the adsorptive properties of SC are described via isothermal and kinetic modelling of two cationic dyes, methylene blue (MB) and safranin-O (SO), whose structure are shown in Figure .