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The increase in the polymer-based materials needs has induced along the waste accumulation, thus argued higher interest in recycling. The study aims to assess the structural, morphological, mechanical resistance, physical–chemical and biochemical characteristics, as well as the preservative role during the curd cheese storage of a recycled polylactic acid (PLA)-based film modified with Ag-graphene-TiO2 nanostructured composite, obtained by recovering the composite from the used film, followed by its incorporation in new PLA. The breaking load of the recycled film was 24% lower than that of the new film and 10% higher than of the neat PLA. Differential scanning calorimetry (DSC) showed changes of the recycled PLA's surface tension and crystallization degree in a greater extent than in the newly prepared film, revealing better incorporation of the recovered composite into the PLA matrix. Fourier transformed infrared spectroscopy showed the formation of C–O–Ti bridges between composite and PLA both in new and recycled film. Oxygen transmission rate (OTR) of the new and recycled film decreased by 33% and 45%, respectively, in comparison with reference PLA. The curd cheese was successfully stored in the recycled packaging; the organoleptic characteristics of cheese wrapped in recycled film were superior in comparison with the new film. The variation of fat and protein contents and mass loss was the lowest when the recycled film was used as packaging material. The study successfully showed the possibility to recover and recycle the used PLA-based films modified with inorganic nanocomposites. [ABSTRACT FROM AUTHOR]

Antimicrobial packaging is an active system used to prevent the development of surface microflora, obtained by adding active agents into the packaging film. The active packaging systems that can extend the shelf life and food safety of products by antimicrobial protection gained interest. The aim of this paper was to obtain modified films based on polyvinyl alcohol (PVA), by adding carvacrol, nutmeg and oregano essential oils, respectively and characterize them by evaluating the tensile strength, the elongation at break and the antimicrobial activity. Moreover, the wettability of the PVA modified with carvacrol onto three types of cheese was also determined. The results have showed that the tensile strength and the elongation at break decrease as the essential oil concentration rises up to 0.75% (mass percentage). No microbial cultures developed at the contact between the film and the culture medium showing that no microorganisms would develop even at the contact of the film with food. The wettability results demonstrated that PVA modified with carvacrol 0.25 % and 0.50 %, respectively are appropriate for the storage of cheese with different moisture and fat content. [ABSTRACT FROM AUTHOR]

Abstract: Three active cellulose-based papers coated in chitosan (P-CH), chitosan-TiO2 (P-CH-TiO2) and chitosan-Ag/TiO2 (P-CH-Ag/TiO2), respectively were real-time aged for 6 months at 4°C, 55% relative humidity, 15 h light/9 h dark cycle and characterized in relation to plain paper (P). The reduction in the chitosan cristallinity, N-deacetylation of chitosan, degradation of cellulosic fibers and loss in the active agents (proven by SEM, FTIR, EDX techniques and physical-chemical-microbial measurements) occurred during storage explains the deterioration of the barrier and antimicrobial properties of the active papers and subsequently the decrease in their preservation efficiency. Experimental results indicate that after storage for 6 months of the clarified butter the most effective package was P-CH-Ag/TiO2 for which the lowest levels of PV (2.72 mEq O2/kg), yeasts and molds (5.8 CFU/g) and E. coli (6.12 CFU/g) counts were measured. By mathematical modeling of the evolution of the PV, E. coli, yeasts and molds experimental profiles the shelf-life of the clarified butter packed in P, P-CH, P-CH-TiO2 and P-CH-Ag/TiO2 was assessed in respect to their admitted limits to 1.6, 2, 4 and 9.3 months, respectively. At the end of storage the appearance of P-CH-Ag/TiO2 package was clean, without greasy spots, as opposed to that of P, P-CH and P-CH-TiO2, which proves its self-cleaning property.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Cotton fabric decorated with TiO2 synthesized by sol‐gel approach was investigated as a self‐cleaning material depending on the TiO2 loading (1.5 wt% in the case of single layered fabric and 3 wt% in the case of double layered). The materials were investigated by SEM, EDX, XRD, FTIR, and photoactivity. The self‐cleaning property was established by determining the amount of the coated dust, the elemental composition, the carbon content, the opacity, and the water contact angle. The self‐cleaning property of the impregnated fabric was accentuated by TiO2 loading. The dust deposited on the single layer fabric stored inside was 3.8 wt% lower than on the nonimpregnated fabric and that deposited on double layer fabric, respectively, was reduced by 9.1 wt%. The decrease in the deposited dust was more accentuated for the samples stored outside (4.2 wt% for the single layer fabric and 16 wt% for the double layer fabric, as compared with the nonimpregnated textile). Schematic mechanism of self‐cleaning [ABSTRACT FROM AUTHOR]

Abstract: Three active cellulose-based papers coated with chitosan (P-CH), chitosan-TiO2 nanocomposite (P-CH-TiO2) and chitosan-Ag/TiO2 nanocomposite (P-CH-Ag/TiO2), respectively, were subjected to real-time ageing for 6 months at 25 °C and 45% re humidity and characterized from a physical-chemical-antimicrobial perspective in relation to plain paper (P). Scanning electron microscopy pictures indicate a smooth morphology in the active papers, while the structure of P is rough with large pores. The fresh papers containing nanocomposites displayed enhanced barrier properties against water vapor, air and grease. The photocatalytic action of TiO2 during ageing results in the deacetylation of the chitosan layer and the degradation of cellulosic fibers with a reduction of barrier properties. Fresh P-CH-Ag/TiO2 displayed the highest value of inhibition index against yeasts and molds (95.65%), its value decreasing to 79.25% after 6-month storage. Walnut kernels were stored for 6 months at 25 °C and 45% RH in packages made of investigated papers and analyzed. It was found that P-CH-Ag/TiO2 is the most effective in the prolongation of the shelf-life of kernels. They are assessed to be safe in terms of peroxide value and yeasts and molds count for 11.6 and 15.1 months when stored in P-CH-Ag/TiO2 filled with 25 and 50 g kernels, respectively, as compared to 1.8 and 3.4 months, respectively when they are stored in P. The appearance of packages containing nanocomposites was clean without grease spots in opposition with that of P and P-CH and proves the self-cleaning property of P-CH-TiO2 and P-CH-Ag/TiO2. Cluster diagrams indicate a strong correlation between the quality and safety of kernels and properties of paper sheets in a paper type-depending manner.Graphical abstract: [ABSTRACT FROM AUTHOR]

This research was undertaken to establish the preservative role of lactic acid (LA) and salicylic acid (SA) included in a gelatin-glycerol film over the harvested plums. The results showed that highest catalase activity was achieved for the plums modified with LA 0.2% wt and with SA 0.00375 M, after 12 days of storage. The most reduced variation of the physical, chemical, and enzymatic parameters was noticed in the plums coated with LA 0.2% wt. Statistical processing showed that the variation of all physical-chemical parameters, excepting catalase is significant. Variation of catalase is significant only in the case of the plums modified with LA 3% wt and of reference plums. Thus, the coating of the harvested plums with a low amount of LA (≤0.2% wt) can be considered as preservation method during storage for 12 days. Practical applications Lactic acid (LA) and salicylic acid (SA) were coated on the harvested plums and their role as preservative during the fruit storage was established. The results showed that coating the harvested plums with a gelatin-glycerol film modified with LA at low concentration (≤0.2% wt) is an efficient method for preservation at room temperature for 12 days, taking in consideration that the commercial shelf life of harvested plums is 2-6 weeks, at 0 °C. [ABSTRACT FROM AUTHOR]

Removal of lead ions from aqueous solutions, in the presence and in absence of commercial TiO2, under UV-light was studied. The influence of catalyst mass, concentration of Pb(II) ions and of citric acid in the starting solution as well as the impact of illumination conditions on the removal rate were also investigated. The results were fitted on the pseudo-first order, pseudo-second order and Elovich kinetic models, Weber-Morris intraparticle and liquid film diffusion models, in order to establish the photoreduction mechanism. The Pb removal rate increased in time by a combined linear-exponential mechanism. The catalyst had a positive influence on the removal rate at the start of the photoreduction. At a low concentration of Pb(II) ions (20 mg/L), the amount of photoreduced Pb(II) ions was proportional to the concentration of the citric acid solution, but at high concentrations (240 mg/L), the correlation was inversely proportional. The rate limiting steps in the removal of lead were both the photoreduction on the TiO2 surface and the diffusion through the film surrounding the catalyst particle. The lead removal was significantly influenced by the mobility and by the concentration of the species in solution. [ABSTRACT FROM AUTHOR]

Two types of graphene oxide-TiO2 composites were prepared: one by including graphene oxide flakes in the TiO2 sol, followed by thermal treatment (GI composite) at 300°C, and the second by including graphene oxide flakes in the calcined (at 500°C) TiO2 xerogel (GII composite). The composites were characterized by SEM, TEM-EDS, TEM-SADP, STEM-HAADF, HRTEM coupled with FT, XRD, and XPS. Photocatalysis results were fitted to different kinetic models (pseudo-first and pseudo-second kinetics, intraparticle Weber-Morris diffusion, film diffusion, and external mass transfer). The results showed that by introducing graphene oxide flakes in the TiO2 sol, followed by thermal treatment at 300°C (GI composite), an efficient graphene oxide-TiO2 catalyst with high specific surface area, heterogeneity, and many graphitized areas can be obtained. Complete crystallization of the composite is not the key issue for the best photoactivity achievement. The rate limiting step in the photocatalytic process is the photooxidation of SA molecules on the TiO2 surface. [ABSTRACT FROM AUTHOR]

Orange juice was stored in polyethylene packages containing Ag- TiO2- Fe or TiO2 composites to establish the extent to which these composites influence the physical-chemical, microbiological and organoleptic characteristics of the juice. The composites were characterized in terms of structure (X-ray diffraction, transmission electron microscopy, Fourier-transformed infrared) and photoactivity while the packages were profiled in terms of their UV-vis absorption and water vapor permeability. The acidity and the browning rate of the sample stored in the package with Ag- TiO2- Fe decreased after 10 days of storage, as compared with the sample deposited in TiO2 packages and with the reference sample (polyethylene). The microbial population in the orange juice increased after 10 days of storage in all packages, but the increase was smaller in the Ag- TiO2- Fe polyethylene package. The organoleptic properties of the fresh orange juice deposited in package with Ag- TiO2- Fe were almost identical with those of the freshly prepared sample (0 days), whereas those of the juice deposited in the reference package were unacceptable. Practical Applications The study provides evidence that the packages of polyethylene modified with Ag- TiO2- Fe can be used to store fresh orange juice for 10 days at room temperature (22.5C). [ABSTRACT FROM AUTHOR]

This study evaluates the photoactivity of novel zeolite-based Ti O2 composites modified with metal particles for the photoreduction of Cu2+, depending on the zeolite and metal particles ( Ag or Fe) content and to establish the photoreduction mechanism. The composites have been prepared by incorporating zeolite particles in the sols during the sol-gel preparation of the Ti O2, followed by impregnation of the gels in solutions containing metal ions. The zeolite-based Ti O2 composites have been characterized using X-ray diffraction, Raman and FTIR spectroscopy techniques and TEM microscopy. The role of zeolite particles in the photoreduction process was demonstrated by using different kinetic models. The apparent constant rate for photoreduction increases in direct proportion with the content of zeolite and is higher for the composites modified with Fe than for those modified with Ag nanoparticles. The results demonstrate that composites have a higher photocatalytic efficiency than Ti O2. The experiments in this study reveal that the migration of Cu2+ in solution occurs rapidly and that the diffusion through the film on the composite's surface and, subsequently, the photoreduction process are the rate limiting steps. The role of the zeolite in photoreduction is to diminish the recombination rate of the charge carriers. [ABSTRACT FROM AUTHOR]