Auditory fovea based speech enchancement and its application to human-robot dialog system

摘要

Bisphenol-A (BPA) is suspected of been endocrine-disrupter and carcinogen. Hence, removal of extensively used BPA by low-cost and efficient coupled-nanomaterials is viewed as vital to environmental protection. Herein, nanocomposite of ZnO doped with zinc-hexacyanoferrate (ZnO@ZnHCF) was employed for photodegradation of BPA. Green synthesized nanocomposite consisted of ZnO wrapped ZnHCF distorted nanocubes piled together. Under daylight, prompt early exponential decline in concentration over time revealed elevated photo-activity of nanocomposite. Improvement in surface-area (113.491 m²g^-1) and band-gap (2.2 eV) of catalyst was resulted from synergism of semiconducting and intercalative feature of ZnO and ZnHCF. At optimum catalyst-dose (25 mg) and neutral pH, photodegradation of BPA (97% of 2 mgL^-1) followed first-order-kinetics involving initial Langmuir adsorption isotherms (R² ≥ 0.996; p ≤ 0.05). Nanocomposites were more effective for greater adsorption of BPA (X_m = 18.0 mg g^-1) than the ZnHCF (10.8 mg g^-1) and ZnO (3.9 mg g^-1). Moreover, doped ZnO@ZnHCF reduced the half-life of BPA upto 2.8 h than that with bared ZnHCF (8 h) and ZnO (17.4 h). GC-MS revealed presence of smaller and safer byproducts clearly supported electron excitement from wrapped-nanocomposite followed by oxidation of BPA with countless OH. Degradation pathways were constructed to track-ways leading to mineralization. Overall, due to greater surface-activity, reusability upto ten-cycles and charge separation (e^-+h⁺ pairs) led to promotion of huge free radicals, ZnO@ZnHCF might be supposed a promising photocatalyst.