Implementing a sustainability approach by converting plastic bottle waste from a mischievous substance to a beneficial material by means of zero residue level concept

Plastic waste represents a serious environmental and health hazard due to its non-biodegradability and toxic leachates. This study investigates the potential conversion of plastic waste into a sustainable raw material for producing a useful substance. This investigation focuses on repurposing PET beverage bottles—a major contributor to microplastic pollution—into high-value activated carbon (AC) for water treatment, aligning with circular economy principles. The chemical preparation method for AC using phosphoric acid as an activating agent was evaluated. Results demonstrated the successful conversion of 68% of plastic waste into AC under the following conditions: pyrolysis temperature of 700°C, pyrolysis time of 7 hours, and PET mass of 200 g. The highest surface area achieved was 590 m2/g under optimized conditions (72-hour impregnation at a 2.5 acid ratio, followed by calcination at 600°C). The environmental applicability of the prepared AC was confirmed through its efficient adsorption of erythrosin B stain (>87% removal at pH 1, 400 rpm agitation speed, and 10 ppm concentration), a common pollutant in textile wastewater. FTIR analysis identified functional groups critical for adsorption, while SEM revealed significant surface modifications post-adsorption (surface area reduction to 161.8 m2/g). To achieve a zero-waste solution, the spent AC was further tested as a rodenticide. Laboratory trials recorded mortality rates with an LD50 consistent with literature values, suggesting a potential dual-purpose application for plastic waste management and pest control. This study presents a scalable approach to addressing plastic pollution while generating value-added materials for environmental and industrial applications.