<abstract> <p>The world is today faced with the problem of plastic waste pollution more than ever before. Global plastic production continues to accelerate, despite the fact that recycling rates are comparatively low, with only about 15% of the 400 million tonnes of plastic currently produced annually being recycled. Although recycling rates have been steadily growing over the last 30 years, the rate of global plastic production far outweighs this, meaning that more and more plastic is ending up in dump sites, landfills and finally into the environment, where it damages the ecosystem. Better end-of-life options for plastic waste are needed to help support current recycling efforts and turn the tide on plastic waste. A promising emerging technology is plastic pyrolysis; a chemical process that breaks plastics down into their raw materials. Key products are liquid resembling crude oil, which can be burned as fuel and other feedstock which can be used for so many new chemical processes, enabling a closed-loop process. The experimental results on the pyrolysis of thermoplastic polymers are discussed in this review with emphasis on single and mixed waste plastics pyrolysis liquid fuel.</p> </abstract>

The aims of this study were to synthesize highly positively charged chitosan nanoparticles (Ch-Np) using the electrospraying technique, and to test their antimicrobial activity against endodontic pathogens, and cytotoxicity against fibroblast cells. Ch-Np were synthesized from low molecular weight chitosan (LMW-Ch) using the electrospraying technique, and characterized. The antimicrobial activity was evaluated against Streptococcus mutans, Enterococcus faecalis, and Candida albicans in their planktonic state using a Time-Kill Test performed by using broth micro-dilution technique, and against biofilm biomass using a microtiter plate biofilm assay. The cytotoxicity was evaluated using Balb/c 3T3 fibroblast cells with the standard MTT assay. Electrospraying of LMW-Ch produced Ch-Np with an average size of 200 nm, and a surface charge of 51.7 mV. Ch-Np completely eradicated S. mutans and E. faecalis in the planktonic state and showed fungistatic activity against C. albicans. Furthermore, it significantly reduced the biofilm biomass for all the tested microbial species [S. mutans (p = 0.006), E. faecalis (p < 0.0001), and C. albicans (p = 0.004)]. When tested for cytotoxicity using 3T3 cells, Ch-Np showed no cytotoxicity. In conclusion, the highly positively charged, colloidal dispersion of Ch-Np are effective as a biocompatible endodontic antimicrobial agent.

The development of next-generation adsorption, separation, and filtration materials is growing with an increased research focus on polymer composites. In this study, a novel blend of chitosan (CS) and polyethylene oxide (PEO) nanofiber mats was electrospun on titanium (Ti)-coated polyethylene terephthalate (PET) track-etched membranes (TMs) with after-treatment by glutaraldehyde in the vapor phase for enhancing the nanofiber stability by crosslinking. The prepared composite, titanium-coated track-etched nanofiber membrane (TTM-CPnf) was characterized by Fourier transform infra-red (FTIR), water contact angle, and scanning electron microscopy (SEM) analyses. Smooth and uniform CS nanofibers with an average fiber diameter of 156.55 nm were produced from a 70/30 CS/PEO blend solution prepared from 92 wt. % acetic acid and electrospun at 15 cm needle to collector distance with 0.5 mL/h flow rate and an applied voltage of 30 kV on the TTM-CPnf. Short (15 min) and long (72 h)-term solubility tests showed that after 3 h, crosslinked nanofibers were stable in acidic (pH ¼ 3), basic (pH ¼ 13), and neutral (pH ¼ 7) solutions. The crosslinked TTM-CPnf material was biocompatible based on the low mortality of freshwater crustaceans Daphnia magna. The composite membranes comprised of electrospun nanofiber and TMs proved to be biocompatible and may thus be suitable for diverse applications such as dual adsorptionefiltration systems in water treatment.

This work was carried out in collaboration between all authors. Author KOEU designed the study and performed the remote sensing and geo statistic analysis. Authors MCI and GTA wrote the protocol and wrote the first draft of the manuscript. Author CCU reviewed and discussed further the implications of the result on the environment. Author IEO managed and reported various implications to the global climate and environmental sustainability. All authors read and approved the final manuscript Article Information