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A submerged photocatalytic membrane reactor (SPMR) was used with suspended and immobilized N–TiO2 under visible irradiation for diclofenac (DCF) removal from wastewater. The effects of initial N–TiO2 concentrations for the SPMR with suspended N–TiO2 were determined for batch processes. Hydrogen peroxide was also coupled with the photocatalytic process. In continuous conditions, a reverse osmosis (RO) membrane was combined with the SPMR for enhancing effluent quality. DCF removal by the SPMR with suspended and immobilized N–TiO2 at a low N–TiO2 dosage (0.5 g/L) was not much different between the two systems, but increased with higher N–TiO2 dosages for the reactor with suspended N–TiO2. Coupling H2O2 with the photocatalytic process under visible irradiation enhanced the DCF removal efficiency. In continuous conditions, DCF concentrations in the photoreactor increased during the reaction time, while those in the effluent (RO permeate) were steady for both systems and both processes. The permeate flux in the reactor with suspended N–TiO2 declined faster than in the reactor with the immobilized N–TiO2. Coupling H2O2 with the photocatalytic process yielded more resistant permeate flux rates. The cake layer formed on the microfiltration membrane of the SPMR with suspended N–TiO2 under visible irradiation was denser than others after completing the process.

Sustainable biopolymers are intriguing motifs for transferring the distinct biocompatibility and recognition into inorganic nanoparticles, which have a potential to be used in biomedicine applications. Here we report scalable production of water-soluble chitosan polymers from N-acetylation. One-pot aqueous synthesis of water-dispersible gold nanospheres is developed using the acetylated chitosan as a stabilizer and a reducing agent. The inherent aqueous solubility of the acetylated chitosan renders the gold nanospheres dispersible in water and enables for controlling the uniform size and monodispersity. The acetylated chitosan-stabilized gold nanospheres with plasmonic and biocompatible properties are used as efficient bioprobes for the selective detection of various biochemical agents of melamine, bacteria, and uric acid.

We introduce for the first time a paper-based analytical device (PAD) for the non-enzymatic detection of glucose by modifying a screen-printed carbon electrode with cobalt phthalocyanine, graphene and an ionic liquid (CoPc/G/IL/SPCE). The modifying composite was characterized by UV-visible spectroscopy, energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The disposable devices show excellent conductivity and fast electron transfer kinetics. The results demonstrated that the modified electrode on PADs had excellent electrocatalytic activity towards the oxidation of glucose with NaOH as supporting electrolyte (0.1M). The oxidation potential of glucose was negatively shifted to 0.64V vs. the screen-printed carbon pseudo-reference electrode. The paper-based sensor comprised a wide linear concentration range for glucose, from 0.01 to 1.3mM and 1.3-5.0mM for low and high concentration of glucose assay, respectively, with a detection limit of 0.67µM (S/N = 3). Additionally, the PADs were applied to quantify glucose in honey, white wine and human serum. The disposable, efficient, sensitive and low-cost non-enzymatic PAD has great potential for the development of point-of-care testing (POCT) devices that can be applied in healthcare monitoring.