Electrospun nylon 6,6 membrane as a reusable nano-adsorbent for bisphenol A removal: Adsorption performance and mechanism.

Bisphenol A (BPA) is highly considered as an emerging contaminants (ECs) due to their endocrine disrupting and reproductive toxicant nature. It has been detected in drinking water sources in many countries. This study deals with the adsorptive removal of BPA using nylon 6,6 nanofibrous membrane (NNM) fabricated by electrospinning technique. Langmuir and Freundlich isotherm models (R2=0.99) were obeyed for BPA adsorption, which indicates the monolayer adsorption of BPA and also surface heterogeneity of NNM. The adsorption kinetics of BPA was followed pseudo second order rate (R2=0.89-0.99), which suggests the occurrence of rapid adsorption rate through interaction of surface functional groups present in NNM. The maximum adsorption of BPA (91.3mgg-1) was attained at 30°C. The hydroxyl groups of BPA form hydrogen bonding with carbonyl groups of NNM during the adsorptive removal process. Reusability study confirmed a much better stability of NNM in the recyclic application. Finally, this study suggests that NNM might be an outstanding nano-adsorbent for the emerging contaminants removal, including BPA from drinking water sources.

Fabrication, characterization and application of laccase-nylon 6,6/Fe3+ composite nanofibrous membrane for 3,3'-dimethoxybenzidine detoxification.

In this study, laccase was immobilized on nylon 6,6/Fe3+ composite (NFC) nanofibrous membrane and used for the detoxification of 3,3'-dimethoxybenzidine (DMOB). The average size and tensile strength of the NFC membrane were found to be 60-80 nm (diameter) and 2.70 MPa, respectively. The FTIR results confirm that the amine (N-H) group of laccase was attached with Fe3+ particles and the carbonyl (C=O) group of NFC membrane via hydrogen bonding. The half-life of the laccase-NFC membrane storage stability was increased from 6 to 11 weeks and the reusability was significantly extended up to 43 cycles against ABTS oxidation. Enhanced electro-oxidation of DMOB by laccase was observed at 0.33 V and the catalytic current was found to be 30 µA. The DMOB-treated mouse fibroblast 3T3-L1 preadipocytes showed maximum (97 %) cell inhibition at 75 µM L-1 within 24 h. The cytotoxicity of DMOB was significantly decreased to 78 % after laccase treatment. This study suggests that laccase-NFC membrane might be a good candidate for emerging pollutant detoxification.