MWCNT-MnO₂ composite and microbial reactor for BPA removal: toxicity and in silico studies

Bisphenol A (BPA) is an emerging harmful endocrine disruptor pollutant, causing hormonal imbalances in the human body. The current study examined multiwalled carbon nanotubes doped with manganese oxide nanoparticle-nanocomposite in a sandwich-type fixed packed bed reactor system. The single-layered system demonstrated 45% removal in the initial 30 mins, whereas the double-layered system displayed 66% removal during the same time. A minimum leaching of Mn²⁺ ions was observed, resulting from oxidation of (BPA) molecules. Mn²⁺ ions leachate was treated at consecutive microbial reactor system, containing chitosan-entrapped Shewanella putrefaciens packed bed reactor, which exhibited a significant removal of both M²⁺ ions and untreated BPA molecules, culminating a pollutant-free discharge. Both treated and untreated BPA samples were screened for toxicity against zebrafish embryos, assisted with computational in silico studies, revealing structural and delayed growth effects by BPA. In contrast, the final treated sample displayed no adverse impacts on the natural growth cycle of zebrafish embryos.