Bioinspired Synthesis of Photocatalytic Nanocomposite Membranes Based on Synergy of Au-TiO₂ and Polydopamine for Degradation of Tetracycline under Visible Light

A bioinspired photocatalytic nanocomposite membrane was successfully prepared via polydopamine (pDA)-coated poly­(vinylidene fluoride) (PVDF) membrane, as a secondary platform for vacuum-filtrated Au-TiO₂ nanocomposites, with enhanced photocatalytic activity. The degradation efficiency of Au-TiO₂/pDA/PVDF membranes reached 92% when exposed to visible light for 120 min, and the degradation efficiency of Au-TiO₂/pDA/PVDF membranes increased by 26% compared to that of Au-TiO₂ powder and increased by 51% compared to that of TiO₂/pDA/PVDF nanocomposite membranes. The degradation efficiency remained about 90% after five cycle experiments, and the Au-TiO₂/pDA/PVDF nanocomposite membranes showed good stability, regeneration performance, and easy recycling. The pDA coating not only served as a bioadhesion interface to improve the bonding force between the catalyst and the membrane substrate but also acted as a photosensitizer to broaden the wavelength response range of TiO₂, and the structure of Au-TiO₂/pDA/PVDF also improves the transfer rate of photogenerated electrons; the surface plasmon resonance effect of Au also played a positive role in improving the activity of the catalyst. Therefore, we believe that this study opens up a new strategy in preparing the bioinspired photocatalytic nanocomposite membrane for potential wastewater purification, catalysis, and as a membrane separation field

Novel Graphene Oxide–Confined Nanospace Directed Synthesis of Glucose-Based Porous Carbon Nanosheets with Enhanced Adsorption Performance

Glucose-based porous carbon nanosheets (GPCNS) were synthesized by an integrated graphene oxide–confined nanospace directed KOH-activated process and were applied as adsorbent for efficient removal of sulfamethazine (SMZ). The effects of GO dosage on the structure, specific surface area, and adsorption capacity of GPCNS-<i>x</i> were investigated. The highest SMZ uptake of 820.27 mg g^–1 (298 K) was achieved in glucose-based porous carbon nanosheets inherited from using 1% GO relative to glucose (GPCNS-1). Also, the adsorption isotherms, thermodynamics, and kinetics of SMZ onto GPCNS-1 were studied in detail. In addition, the effects of ionic strength and solution pH on the adsorption capacity of GPCNS-1 were also investigated, indicating good environmental tolerance of GPCNS-1. Furthermore, regeneration experiments showed that GPCNS-1 has good reproducibility and durability. We believe that these graphene oxide–confined nanospace directed KOH-activated process biomass-based carbon nanosheets are highly promising as absorbents in the field of environmental protection

Bioinspired Synthesis of Janus Nanocomposite-Incorporated Molecularly Imprinted Membranes for Selective Adsorption and Separation Applications

Inspired from the biomimetic polydopamine (pDA)-based self-polymerization technique and Janus nanocomposite structure, an efficient yet simple method of pDA@Au-based Janus-incorporated molecularly imprinted nanocomposite membranes (MINCMs) has been developed. The Janus nanocomposite was obtained by using pDA nanospheres as the supports, and the catechol-reduced Au nanoparticles from Au ions were then grown on the surfaces of pDA nanospheres. Highly regenerative performance and selective separability toward tetracycline (TC) were finally obtained. Because of the formation of this membrane-based Janus nanocomposite surfaces, largely enhanced TC-rebinding capacities (67.43 mg/g), permselectivity (separation factors were all more than 10.5) and rebinding stability (93% of the saturated adsorption capacity after 11 cycling adsorption/desorption cycles) were finally obtained. These results strongly illustrated that incorporation of the Janus nanocomposite into molecularly imprinted membranes would achieve both the high rebinding capacity and the excellent permselectivity. All the synthesis processes were carried out at low temperature and ordinary pressure, which were energy-efficient and environmentally friendly for large-scale applications