The Fusion of Elemental Sulfur With Waste Cooking Oil-Based Derivatives: Beyond Renewability

Abstract

Elemental sulfur (S₈), previously the powerhouse of modern society, and waste cooking oil (WCO) are nowadays surplus industrial by-products from oil-refinery and food processing industries, respectively, generating growing environmental concerns and economic loss. These unavoidable wastes, which are inherent in the aforementioned processes, cannot be minimized without substantial advances in technology and/or significant modifications in consumer behavior. Indeed, there are ongoing research activities to enable a powerful strategy for upcycling these wastes into valuable and useful products, that is, conversion to high-sulfur content polymeric materials (also known as polysulfides). Among those research activities, the ones focusing on the utilization of the inverse vulcanization (IV), the reverse version of the well-known vulcanization process, provides a facile and straightforward method that allows the use of S₈ and the WCO derivatives as the respective olefin components essential for the process. Thus, in this mini-review a brief overview of the recent outcomes, challenges, and opportunities of the valorization of WCO and S₈ toward the synthesis of high-sulfur content polymeric materials are discussed. Besides, exemplary studies are provided to illustrate the versatility of these materials in applications ranging from energy storage to heavy metal remediation, as well as prospects for industrial use.

Practical Applications: Beyond highlighting existing applications, this review serves as a comprehensive guide to exploring new opportunities in the field, paving the way for future research and development. Crucially, the discussion extends to industrial scalability, commercialization prospects, and closed-loop production strategies, evaluating the feasibility of waste-cooking derived IV polymers in next-generation sustainable manufacturing and green technology solutions.