Eco-design of a low-cost adsorbent produced from waste cherry kernels

Industrial wastewater polluted with heavy metals presents significant ecological and health risks. Such wastewater can be efficiently decontaminated with activated carbon. Waste cherry kernels are a low-cost material used to produce non-conventional activated carbon. This research applies life cycle assessment, comparative adsorption study, and cost analysis to achieve an eco-design-based process to produce activated carbon from waste cherry kernels. The results from three analyses of commercial activated carbon and a low-cost adsorbent made from waste cherry kernels were compared. Producing activated carbon from waste cherry kernels had major environmental impacts associated with consumption of electricity and phosphoric acid. For the human toxicity impact category, characterization results were 3.91E-07 and 1.17E-07 disability-adjustment life years for electricity and phosphoric acid consumption, respectively. Endpoint results from all categories showed that alternative activated carbon has the lowest total environmental impact, a total of 585 mPt, whilst the largest impact, 739 mPt, is due to commercial activated carbon. The adsorption study showed that activated carbon produced from waste cherry kernels had heavy metal removal rates of 79–95% and 90–92% for Pb2+ and Cd2+, respectively. On the other hand, with a removal rate of 84–88%, commercial activated carbon showed better results for Ni2+. The cost analysis results indicated that activated carbon produced from waste cherry kernels is more than six times cheaper than commercial activated carbon and can provide savings of 229 US$/kg. The practical applications of activated carbon made from waste cherry kernels are the same as those of commercial activated carbon, and include use in air and water purification filters for heavy metals, hydrocarbons, and organic contaminants.