Robust optimization of sustainable omnichannel closed-loop food supply chain network: Integrating blockchain, IoT, and biofuel production

The increasing complexity of the global food supply chain network under demand uncertainties calls for solutions that improve efficiency, transparency, and sustainability. This study develops a bi-objective, multi-period omnichannel framework that integrates Internet of Things (IoT), blockchain technology, and food waste reuse for biofuel production. Omnichannel strategies optimize the flow of goods across multiple channels, addressing the fragmented nature of modern supply chains. The study highlights the role of blockchain in improving transparency in food transportation and tracking, while IoT-enabled RFID tracking facilitates real-time data collection and monitoring. Together, these technologies improve brand value by strengthening consumer trust and overall supply chain credibility. To address uncertainties in demand and supply, the framework uses robust optimization techniques. The model is solved using an ϵ-constraint method, capturing the trade-off between minimizing costs and reducing carbon emissions. We then use a Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to select the most preferred solutions for each instance. Numerical experiments on small-, medium-, and large-scale instances show that the integrated blockchain–IoT framework increases cost by 59%, 55%, and 39%, respectively, compared to 1–21% for IoT-only and 24–38.57% for blockchain-only implementations. Carbon emissions decrease by up to 3.81% in large-scale scenarios. The results also demonstrate that brand value increases with scale, with the highest brand value achieved when both IoT and blockchain are integrated. These findings provide valuable insights for designing sustainable, transparent, and efficient supply chains that balance cost, environmental impact, and brand reputation.