Sustainable struggling: decoding microplastic released from bioplastics-a critical review.

This comprehensive review delves into the complex issue of plastic pollution, focusing on the emergence of biodegradable plastics (BDPs) as a potential alternative to traditional plastics. While BDPs seem promising, recent findings reveal that a large number of BDPs do not fully degrade in certain natural conditions, and they often break down into microplastics (MPs) even faster than conventional plastics. Surprisingly, research suggests that biodegradable microplastics (BDMPs) could have more significant and long-lasting effects than petroleum-based MPs in certain environments. Thus, it is crucial to carefully assess the ecological consequences of BDPs before widely adopting them commercially. This review thoroughly examines the formation of MPs from prominent BDPs, their impacts on the environment, and adsorption capacities. Additionally, it explores how BDMPs affect different species, such as plants and animals within a particular ecosystem. Overall, these discussions highlight potential ecological threats posed by BDMPs and emphasize the need for further scientific investigation before considering BDPs as a perfect solution to plastic pollution.

Harnessing bio-based chelating agents for sustainable synthesis of AgNPs: Evaluating their inherent attributes and antimicrobial potency in conjunction with honey.

Greenly synthesized nanoparticles have garnered attention due to their low environmental footprint, but impurities limit their applications. A novel semi-organic method for synthesizing silver nanoparticles (AgNPs) using bio-based chelating fuels (Beta vulgaris subsp., Spinacia oleracea, and Ipomoea batatas) reduces the undesirable impurities. The study also showcases the impact of bio-based chelating fuel on various characteristics of AgNPs in comparison to synthetic chelating fuel. The antimicrobial efficacy of the synthesized AgNPs in conjunction with honey was also assessed against E. coli. The XRD analysis showed cubic structure of AgNPs. The FESEM and TEM analysis showed that the well-connected spherical-shaped AgNPs (∼3-120 nm diameter) while EDS confirmed the presence of Ag in all samples. The TEM analysis also revealed layers of carbonates in AgNPs synthesized using bio-based chelating fuels. XPS investigation confirmed the absence of any prominent impurities in prepared samples and AgNPs have not experienced oxidation on their surface. However, notable surface charging effects due to the uneven conductivity of the particles were observed. The broth dilution method showed that all mixtures containing AgNPs in combination with honey exhibited a significant bacterial growth reduction over a period of 120 h. The highest growth reduction of ∼75 % is obtained for the mixture having AgNPs (Ipomoea batatas) while the least growth reduction of ∼51 % is obtained for the mixture having AgNPs (Beta vulgaris subsp.). The findings affirm that AgNPs can be successfully synthesized using bio-based chelating fuels with negligible ecological consequences and devoid of contaminants. Moreover, the synthesized AgNPs can be employed in conjunction with honey for antibacterial purposes.

Innovative tarantula hair-inspired washing machine filters for enhanced microfiber capture.

Aquatic environments are being polluted by microplastics primarily originating from the washing of synthetic textiles. Microfibers (MF), which are microplastics in synthetic fibers, are consistently introduced into the environment with each domestic laundry cycle. To address this issue, we developed a specialized MF capture "barbed filter" (BF) by transforming PET monofilaments of different diameters (0.4, 0.6, and 0.8 mm) into structures that closely resemble the characteristics of tarantula urticating hairs. BFs feature sharp barbs that effectively capture and retain microfibers of diverse lengths, surpassing the performance of conventional control filters. The BFs had a retention efficiency of 88-91 %, while the CFs had an efficiency of 79-86 %. Our findings revealed that the barbed filter significantly outperformed the conventional control filter in capturing microfibers due to its smaller pore size, shorter pore distance, and unique filter shape. This design not only enhances the surface area and friction, facilitating microfibril strong entrapment but also minimizes the probability of microfibril passage through the filter. This research offers a promising solution for reducing microfibril release from laundry and textile industrial wastewater. The implementation of BFs in real life has the potential to significantly reduce microplastic pollution and promote a cleaner and more sustainable environment.

Enhancing air treatment through controlled fabrication of transition metal-doped titanium dioxide nanocomposites for photocatalytic toluene degradation.

Rapid industrial growth and urbanization have resulted in a significant rise in environmental pollution issues, particularly indoor air pollutants. As a result, it is crucial to design and develop technologies and/or catalysts that are not only cost-effective but also promising high performance and practical applicability. However, achieving this goal has been so far remained a challenging task. Herein, a series of transition metal M - TiO2 (M = W, Fe, Mn) nanocrystals was prepared for photocatalytic degradation of volatile organic compounds (VOCs), i.e., toluene. Of the nanocomposites tested, W-TiO2 showed significantly improved photocatalytic activity for VOC degradation under UV irradiation compared to the others. In particular, the optimized W dopant amount of 0.5 wt% resulted in the outstanding degradation performance of toluene (96%) for the obtained W-TiO2(0.5%) nanocomposite. Moreover, W-TiO2(0.5%) nanocomposite exhibited good stability for 32 h working under high toluene concentration (10 ppm) compared to the pristine TiO2. The current work demonstrates the potential usage of M - TiO2 nanocrystals, particularly W-TiO2(0.5%), as a promising photocatalyst for efficient VOCs degradation.

Enhancing Textile Water Repellency with Octadecyltrichlorosilane (OTS) and Hollow Silica Nanoparticles.

Superhydrophobic coatings have attracted substantial attention owing to their potential application in various industries. Conventional textiles used in daily life are prone to staining with water and household liquids, necessitating the development of water-repellent and stain-resistant coatings. In this study, we fabricated a highly water-repellent superhydrophobic PET fabric by using an eco-friendly water-based coating process. Fluorine-free octadecyltrichlorosilane (OTS) solutions with various wt.% of hollow silica (HS) nanoparticles were used to produce a superhydrophobic surface via a facile dip coating method. Our findings revealed that the incorporation of HS nanoparticles substantially increased the water contact angle, with higher concentrations resulting in enhanced water repellency and increased surface roughness. The treated fabrics had a remarkable water contact angle of 152.4° ± 0.8°, demonstrating their superhydrophobic fiber surface. In addition, the durability of these superhydrophobic properties was investigated via a laundry procedure, which showed that the fabrics maintained their water repellency even after 20 laundering cycles. EDX and XRD analyses confirmed that the morphological evaluations did not reveal any substantial structural alterations. Significantly, the fibers maintained their strength and durability throughout the testing, enduring only minor hollow SiO2 nanoparticle loss. This eco-friendly and cost-effective method holds great potential for application in apparel and other industries, offering an effective solution to resist water stains and improve performance in various contexts.

SARS-CoV-2 airborne transmission: a review of risk factors and possible preventative measures using air purifiers.

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resulting worldwide death toll have prompted worries regarding its transmission mechanisms. Direct, indirect, and droplet modes are the basic mechanisms of transmission. SARS-CoV-2 spreads by respiratory droplets (size range >10 µm size ranges), aerosols (5 µm), airborne, and particulate matter. The rapid transmission of SARS-CoV-2 is due to the involvement of tiny indoor air particulate matter (PM2.5), which functions as a vector. SARS-CoV-2 is more contagious in the indoor environment where particulate matter floats for a longer period and greater distances. Extended residence time in the environment raises the risk of SARS-CoV-2 entering the lower respiratory tract, which may cause serious infection and possibly death. To decrease viral transmission in the indoor environment, it is essential to catch and kill the SARS-CoV-2 virus and maintain virus-free air, which will significantly reduce viral exposure concerns. Therefore, effective air filters with anti-viral, anti-bacterial, and anti-air-pollutant characteristics are gaining popularity recently. It is essential to develop cost-effective materials based on nanoparticles and metal-organic frameworks in order to lower the risk of airborne transmission in developing countries. A diverse range of materials play an important role in the manufacturing of effective air filters. We have summarized in this review article the basic concepts of the transmission routes of SARS-CoV-2 virus and precautionary measures using air purifiers with efficient materials-based air filters for the indoor environment. The performance of air-filter materials, challenges and alternative approaches, and future perspectives are also presented. We believe that air purifiers fabricated with highly efficient materials can control various air pollutants and prevent upcoming pandemics.

Melamine sponge-based copper-organic framework (Cu-CPP) as a multi-functional filter for air purifiers.

COVID-19 has drawn great attention on the necessity for establishing pathogen-free indoor air. This paper offers an insight into the potential application of a multi-purpose filter to remove fine particulates and disinfect pathogens using melamine sponge with a copper-organic framework. In-situ growth dip coating method was applied to coat Cu-based coordination polymer particle (Cu-CPP) on melamine sponge (MS). The integration of Cu-CPPs with high crystallinity and highly active surface area (1,318.1 m2/g) enabled Cu-CPP/MS to have an excellent capture rate (99.66%) and an instant disinfection rate of 99.54% for Escherichia coli. Electrostatic attraction seemed to play a crucial role in capturing negative-charged pathogens effectively by positive charges on Cu-CPP arising from unbalanced copper ions in Cu-CPP. Disinfection of pathogens was mainly attributed to catalytically active Cu2+ sites. Organic ligand played an important role in bridging and maintaining Cu2+ ions within the framework. This study highlights the design of a new capture-and-disinfection (CDS) air filter system for pathogens using Cu-CPP/MS. It can be applied as a substitute for conventional high-efficiency particulate air (HEPA) filters. Electronic Supplementary Material: Supplementary material is available for this article at 10.1007/s11814-021-1000-4 and is accessible for authorized users.