Complementary Bifunctional Unique Properties of (α,β)‐PbO Nanoparticles for Efficient Catalysis and Adsorption for Water Remediation

Abstract

Lead oxides (PbO) of same chemical composition, but different crystallographic properties have been developed for complementary catalytic ozonation (designated by [PbO]a) and adsorption (designated by [PbO]b) of a model dye, reactive red–120 (RR‐120) with highest possible efficiency beyond the state‐of‐the‐art of individual processes. The highest extent of decolouration (∼99% after 4 min) with kappRR-120 1.77×10−2 s−1 and mineralization (50% after 15 min) of RR‐120 at pH 10.5 was achieved by ozonation using 0.5 g/L catalyst [PbO]a consisting major fraction of α‐PbO phase (α‐PbO: β‐PbO∼4:1) in its crystal structure. Minimum adsorption of RR‐120 (∼7%) on catalyst's surface [PbO]a led to higher accessibility of O3 to free catalyst surface sites and helped to achieve highest efficiency of catalytic ozonation. On the other hand, adsorbent [PbO]b mainly consisting of β‐PbO phase (α‐PbO: β‐PbO∼1:4) with a fractional coexistence of α‐PbO phase showed excellent adsorption of RR‐120 (571 mg/g at 320 K) at pH 7.5, but it showed inferior efficiency in catalytic ozonation. Both the materials were found to be reusable and environmentally acceptable.