Scarcity of water is still the most critical issue facing the world today. It is further compounded by high population growth, pollution, and climate change. Traditional means of desalination are effective but tend to be energy-intensive, resource-expensive, and environmentally demanding. This research explores a novel, environmentally friendly method of seawater desalination in the creation of low-cost biofilters made from crop waste. Banana plant stems and orange peels were transformed into powdered and activated carbon forms and blended into polyurethane foam matrices to achieve bioadsorptive filters. The materials were examined through pH analysis, granulometry, ash content, zeta potential, and FTIR spectroscopy to identify their physicochemical properties. Experimental tests yielded impressive improvements in adsorption capacity, with orange-peel-filter-activated samples recording a 31.5% particle size reduction and up to 72% removal of copper (Cu²⁺) and 68% removal of cadmium (Cd²⁺) under optimized conditions. A portable appliance, the "Magique Cup," was also introduced in this study, which can be applied in homes for water treatment using filters. Regeneration tests also indicated that up to 85% of the original adsorption capacity could be recovered through acid or heat treatment. The findings show the potential of biodegradable, waste-derived biofilters to provide successful alternatives to traditional desalination processes. Scaling of the technology, long-term filter stability, and field-operating performance should be tackled in subsequent research.