Aggregation-induced type I&II photosensitivity and photodegradability-based molecular backbones for synergistic antibacterial and cancer phototherapy via photodynamic and photothermal therapies.

The clinical applications of phototherapy nanomaterials are still limited due to concerns regarding their phototoxicity and efficacy. Herein, we report a novel type of D-π-A molecular backbone that induces type I/II photosensitivity and photodegradability by forming J-aggregates. The photodegradation rate can be regulated by changing the donor groups to regulate the photosensitivity of their aggregates because the photodegradability performance results from their oxidation by 1O2 generated by their type II photosensitivity. AID4 NPs possess faster photodegradation because of their better type I&II photosensitivity, which can also self-regulate by inhibiting type II and improving type I under hypoxic conditions. Moreover, they exhibited good photothermal and photoacoustic performance for improving their therapeutic effect by a synergistic effect and achieving photoacoustic imaging in vivo. The experimental result also showed that they can be effective for antibacterial and anti-tumor treatment and the photodegradation products of AID4 NPs possess low biological toxicity in the dark or under light. This study could provide a novel strategy for improving the safety and treatment effects of phototherapy.

Hybrid functionalized chitosan-Al2O3@SiO2 composite for enhanced Cr(VI) adsorption.

In this study, we prepared a novel hybrid functionalized chitosan-Al2O3@SiO2 composite (FCAS) for removing hexavalent chromium [Cr(VI)] from aqueous system. Spectroscopic studies like Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive spectroscope (EDS) were characterized. The effects such as dosage of adsorbent, pH, contact time and initial Cr(VI) concentration were evaluated. It has been illustrated that a wide acidic condition in the pH range of 2-6 was conducive to Cr(VI) adsorption and only 10 min was required to reach about 80% adsorption. Also, the adsorption properties of prepared adsorbent such as kinetics, thermodynamics and isotherms were comprehensively studied. Additionally, the adsorption capacity barely declined even after five cycles. Studies found that FCAS with characteristics of high performance of adsorption rate and capacity and better reusability would be a potential adsorbent for wastewater treatment.

Performance and microbial population dynamics during stable operation and reactivation after extended idle conditions in an aerobic granular sequencing batch reactor.

The evolution of removal performance and bacterial population dynamics of an aerobic granular sequencing batch reactor were investigated during stable operation and reactivation after prolonged storage. The system was run for a period of 130days including the stable condition phase, storage period and the subsequent reactivation process. Excellent removal performance was obtained during the stable operation period, which was decayed by the extended idle conditions. The removal efficiencies for both carbon and nitrogen decayed while phosphorus removal remained unaffected. Both granules structure and physical properties could be fully restored. Microbial populations shifted sharply and the storage perturbations irreversibly altered the microbial communities at different levels. Extracellular polymeric substances (especially protein) and key groups were identified as contributors for storage and re-startup of the aerobic granular system.

Chronic responses of aerobic granules to zinc oxide nanoparticles in a sequencing batch reactor performing simultaneous nitrification, denitrification and phosphorus removal.

The reactor performance, granules characteristics and microbial population dynamics were investigated to assess the chronic responses of aerobic granules to zinc oxide nanoparticles (ZnO NPs) of 0, 5, 10 and 20mg/L for a period of 180days. The results showed that ZnO NPs stimulated COD removal, whereas caused inhibition to both nitrification and denitrification. However, biological phosphorus removal remained effective and stable. Introduction of ZnO NPs sharply decreased the respiration of granules, while did not change the settleability. Both content of extracellular polymeric substances (EPS) and the ratio of protein to polysaccharides (PN/PS) rose significantly. MiSeq pyrosequencing was employed to explore the microbial population dynamics. Results demonstrated that up to 20mg/L reduced the alpha-diversity of bacterial communities. Finally, phylogenetic classification of the dominant functional species involved in biological nutrients removal were identified to assess the effects of ZnO NPs to aerobic granules from the molecular level.

Insight into the impact of ZnO nanoparticles on aerobic granular sludge under shock loading.

The increasing use of zinc oxide nanoparticles (ZnO NPs) has raised concerns about the environmental threats to the wastewater treatment systems. Shock loading of 10, 50 and 100 mg/L ZnO NPs was conducted to evaluate impacts on reactor performance, microbial activities and extracellular polymeric substances (EPS) in parent aerobic/oxic/anoxic (A/O/A) granular sequencing batch reactors (SBRs). The results showed that ZnO NPs caused inhibition to nitrogen transformations due to acute toxicity to nitrification and denitrification. However, phosphorus removal remained unaffected by the exposure to ZnO NPs. Besides, ZnO NPs significantly enhanced the oxygen respiration rate and caused acute toxicity to ammonia oxidizing rate (10.40-35.21%), phosphorus release rate (37.79-19.80%), aerobic phosphorus uptake rate (36.95-20.69%) and total phosphorus uptake rate (32.77-16.91%) of aerobic granules. ZnO NPs stimulated the secretion of EPS, especially the content of protein (PN), which could relieve the toxicity of ZnO NPs.

Unraveling characteristics of simultaneous nitrification, denitrification and phosphorus removal (SNDPR) in an aerobic granular sequencing batch reactor.

An aerobic granular sequencing batch reactor (SBR) on an aerobic/oxic/anoxic (AOA) mode was operated for 50days with acetate sodium as the sole carbon source for simultaneous carbon, nitrogen and phosphorus removal. Excellent removal efficiencies for chemical oxygen demand (COD) (94.46±3.59%), nitrogen (96.56±3.44% for ammonia nitrogen (NH4(+)-N) and 93.88±6.78% for total inorganic nitrogen (TIN)) and phosphorus (97.71±3.63%) were obtained over operation. Mechanisms for simultaneous nutrients removal were explored and the results indicated that simultaneous nitrification, denitrification and phosphorus removal (SNDPR) under aerobic conditions was mainly responsible for most of nitrogen and phosphorus removal. Identification and quantification of the granular AOA SBR revealed that higher rates of nutrients removal and more potentials were to be exploited by optimizing the operating conditions including time durations for AOA mode and the feeding compositions.