In this study, we developed a highly active floatable photocatalyst by incorporating BiOCl/BiOBr heterojunctions with abundant oxygen vacancies (OVs) onto fly ash cenospheres (FACs) composites, aiming to enhance the efficiency of tetracycline (TC) removal. The physicochemical properties of resulting composites were analyzed using various characterization techniques. The findings demonstrated the uniform anchoring of nanosheet-array-like BiOCl, BiOBr, or BiOCl/BiOBr heterojunctions on the surface of FACs. Intriguingly, the BiOCl/BiOBr heterojunctions exhibited an increased content of OVs compared to BiOCl and BiOBr alone. The degradation experiments of TC revealed that the BiOCl/BiOBr@FACs composites displayed optimal photodegradability, which was further enhanced by the assistance of peroxymonosulfate (PMS). Furthermore, through active species capture experiments and ESR analysis, we proposed a synergistic reactive mechanism that differed from single photocatalytic processes and traditional PMS activation. Active species such as h+, 1O2, ·O2-, ·OH and ·SO4- were found to participate in the synergistic process of TC degradation, in which the presence of PMS promoted the production of ·O2- via OVs active sites instead of inhibition. Importantly, the immobilized BiOCl/BiOBr@FACs composites exhibited floatability on the water surface and were readily excited by visible light, making them suitable for reuse and practical applications. This study presents an innovative approach for designing recyclable photocatalysts and achieving efficient wastewater treatment with the assistance of PMS.

Nowadays, ammonia-responsive biopolymer-based intelligent active films are of great interest for their huge potential in maintaining and monitoring the freshness of seafood. However, it is still a challenge to create biopolymer-based intelligent active films with favorable color stability, antibacterial and visual freshness indication functions. Herein, cobalt-based metal-organic framework (Co-MOF) nanosheets with ammonia-sensitive and antibacterial functions were successfully synthesized and then embedded into carboxymethyl cellulose (CMC) matrix to develop high performance and multifunctional CMC-based intelligent active films. The influence of Co-MOF addition on the structure, physical and functional characters of CMC film was comprehensively studied. The results showed that the Co-MOF nanofillers were homogeneously embedded within the CMC matrix, bringing about remarkable promotion on tensile strength (from 45.3 to 62.2 MPa), toughness (from 0.7 to 2.3 MJ/m3), water barrier and UV-blocking performance of CMC film. Notably, the obtained CMC/Co-MOF nanocomposite films also presented excellent long-term color stability, antibacterial activity (with the bacteriostatic efficiency of 99.6 % and 99.3 % against Escherichia coli and Staphylococcus aureus), and ammonia-sensitive discoloration performance. Finally, the CMC/Co-MOF nanocomposite films were successfully applied for realtime visual monitoring of shrimp freshness. The above results demonstrate that the CMC/Co-MOF nanocomposite films possess huge potential applications in intelligent active packaging.

Fly-ash-based geopolymer pastes with the addition of expanded vermiculite (EV) powder were synthesised and their microstructure, compressive strength, setting time, moisture control, extent of efflorescence and thermal conductivity were studied. It was found that the addition of EV resulted in an increase in the standard-consistency water consumption and setting times. As a consequence, excessive addition of EV resulted in a larger amount of harmful pores, which was detrimental for the compressive strength of the paste. However, geopolymer pastes with an appropriate amount of EV (2–7 wt%) showed a slight increase in compressive strength because of the filler effect. Mg 2+ and Fe 3+ diffused from the EV interlayers through ion exchange between the EV and the geopolymer, and participated in geopolymerisation. This was reflected by the formation of N-(M)-A-(F)-S-H, as evidenced by scanning electron microscopy with energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. In addition, Na + /Mg 2+ or Na + /Fe 3+ ion exchange reduced the mobility of Na + the ions and therefore decreased the extent of efflorescence. Moreover, EV addition favoured an improvement in moisture content and the thermal conductivity properties of the geopolymer paste.

An advanced oxidation process was developed under LED blue light (BL) photocatalysis in the presence of ammonium persulfate (APS) for effective degradation of tetracycline (TC) from contaminated water. Waste rock wool (RW) fibers modified with BiOBr nano-sheet (BiOBr/RW) using impregnation combined with hydrolysis process, was employed to activate APS to produce reactive radicals under LED BL irradiation (BiOBr/RW+APS+BL system). The influence factors on TC degradation were investigated. Besides, the radical scavengers such as methanol (MA), phenol (PN), tertbutanoland (TBA) and ethylene diamine tetraacetate (EDTA-2Na) combined electron spin paramagnetic resonance (EPR) analysis were used to confirm the reactive radical species. The developed BiOBr/RW+APS+BL system exhibited much higher TC removal efficiency compared with other reported oxidation systems. In addition, the BiOBr/RW could directly activate the APS leading to degrade TC in the darkness. A maximum TC removal of 84.3% was achieved under the optimal conditions such as initial concentration of APS 100 mg/L, BiOBr/RW dosage 0.1 g/L and pH 7 in 80 min. Results also ascertained that h(+), center dot OH and center dot SO4- over surface of the BiOBr/RW were the primary active chemical species in the BiOBr/ RW+APS+BL system. It was found that the center dot OH and center dot SO4- in solution play critical roles for degradation of TC on the BiOBr/RW+APS system in dark. Finally, the repeated experiments indicated the excellent stability, photocatalytic ability and cycling property of BiOBr/RW.

Nanocomposites of high-density polyethylene (HDPE) modified with 0.2 phr graphene-zinc oxide (GN-ZnO) exhibited optimal mechanical properties and thermal stability. Two other nano-materials—GN and nano-ZnO—were also used to compare them with GN-ZnO. Increasing the content of GN-ZnO gradually enhanced the antibacterial and barrier properties, but the addition of 0.3 phr GN-ZnO led to agglomeration that caused defects in the nanocomposites. Herein, we investigated the antibacterial and barrier properties of HDPE nanocomposites infused with different nanoparticles (GN, ZnO, GN-ZnO) of varying concentrations. HDPE and the nanoparticles were melt-blended together in a Haake-Buchler Rheomixer to produce a new environment-friendly nano-material with improved physical and chemical properties. The following characterizations were conducted: tensile test, thermogravimetric analysis, morphology, differential scanning calorimetry, X-ray diffraction, antibacterial test, and oxygen and water vapor permeation test. The results showed that the crystallinity of HDPE was affected with the addition of GN-ZnO, and the nanocomposites had effective antibacterial capacity, strong mechanical properties, high thermal stability, and excellent barrier performance. This type of HDPE nanocomposites reinforced with GN-ZnO would be attractive for packaging industries.

In this paper, nanosilver and carbon nanotubes was melt blended with HDPE and pet respectively to prepare HDPE/CNT/nanosilver and PET/CNT/nanosilver composites with antibacterial effect. After the preparation of samples, SEM, DSC, TGA, mechanical properties and antibacterial properties were tested. The possibility of preparing new materials by this method is studied. Compared with pure HDPE, when the content of CNT/nanosilver is 0.1 phr, the tensile strength of HDPE/CNT/nanosilver composite reach to the max value.

Graphene that consists of less than 10 layers is expensive; moreover, it tends to agglomerate. These disadvantages restrict its utility. In this regard, the present study aimed to reduce the number of layers of a functionalized graphene (FG) with 10-30 layers to less than 10 layers by using an ultrasonic processor. We prepared nanocomposite films of polyvinyl alcohol (PVA) incorporated with FG by a simple hydrothermal method and ultrasonic dispersion. Oxygen transmission rate and water vapor permeability were considerably increased on account of modifying PVA with FG. Furthermore, the mechanical properties, thermostability, and barrier properties were improved. The barrier efficiency of the nanocomposites at different temperatures remained high for long periods of operation because of the network bonding. A simple procedure involving relatively low-cost nanomaterials could unlock the potential of nanocomposite FG/PVA films in the fields of coating, packaging, and semiconductor materials.