Utilizing Undissolved Portion (UNP) of Cement Kiln Dust as a Versatile Multicomponent Catalyst for Bioethylene Production from Bioethanol: An Innovative Approach to Address the Energy Crisis.

This study focuses on upcycling cement kiln dust (CKD) as an industrial waste by utilizing the undissolved portion (UNP) as a multicomponent catalyst for bioethylene production from bioethanol, offering an environmentally sustainable solution. To maximize UNP utilization, CKD was dissolved in nitric acid, followed by calcination at 500 °C for 3 h in an oxygen atmosphere. Various characterization techniques confirmed that UNP comprises five different compounds with nanocrystalline particles exhibiting an average crystal size of 47.53 nm. The UNP catalyst exhibited a promising bioethylene yield (77.1%) and selectivity (92%) at 400 °C, showcasing its effectiveness in converting bioethanol to bioethylene with outstanding properties. This exceptional performance can be attributed to its distinctive structural characteristics, including a high surface area and multiple-strength acidic sites that facilitate the reaction mechanism. Moreover, the UNP catalyst displayed remarkable stability and durability, positioning it as a strong candidate for industrial applications in bioethylene production. This research underscores the importance of waste reduction in the cement industry and offers a sustainable path toward a greener future.