A Critical Review of Ion Flotation as a Sustainable Wastewater Treatment Technique: Scope, Efficiency, and Application

Ion flotation has developed as an important technology for selectively removing heavy metal ions from contaminated aquatic environments, including wastewater. This review meticulously analyzes the foundational principles, advancements, and practical implementations of ion flotation, with an emphasis on its efficacy, operational flexibility, and sustainability. The paper explores various flotation approaches, including conventional ion flotation, precipitate flotation, and hybrid sorptive and biosorptive systems, shedding light on their underlying mechanics, performance metrics, and operational variables.  Prior studies show that optimizing conditions can result in removal rates over 90% for pollutants like Pb²⁺, Cd²⁺, Cu²⁺, and Zn²⁺. Innovations in surfactant chemistry, Nano-enhanced collectors, and bio-sorbents have augmented selectivity, reduced chemical consumption, and bolstered environmental compatibility. Precipitate flotation demonstrates enhanced efficacy in multi-metal systems, while biosorptive flotation presents economical and ecologically sustainable alternatives. Nonetheless, obstacles such as collector recovery, foam stability, and challenges associated with scale-up persist as substantial impediments. This analysis finds that ion flotation, particularly in its advanced and hybridized forms, has significant potential for integration into sustainable wastewater treatment paradigms. Future inquiries should emphasize pilot-scale validation, system integration, and life-cycle analysis to facilitate broader industrial applicability and alignment with the objectives of a circular economy