White Pollution Research Articles

Microbial fuel cell-based biosensor for monitoring anaerobic biodegradation of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)

Poly-3-hydroxybutyrate-co-4-hydroxybutyrate (P34HB) polymer, which is a common type of polyhydroxyalkanoates (PHAs), may provide alternative solutions to the white pollution issues. In this study, its anaerobic biodegradation was investigated through the microbial fuel cell (MFC) system, by monitoring several parameters, including the time-dependent changes in the electrical signals, the concentration of the P34HB degradation products, biogas production, the weight loss of P34HB films, and the morphological and chemical structure of the test materials during the degradation. Notably, the electrical signal was selected as an indicator to online monitor the anaerobic biodegradation of P34HB films. After 40 days of degradation, the coulombic yield biodegradability (Q-biodegradability) of P34HB films reached 37.59%. A linear relationship among the weight loss biodegradability of P34HB films and Q-biodegradability with high correlation coefficient of R2 = 0.998 was established. The results suggested that the anaerobic biodegradability of P34HB films can be efficient measured by using the Q-biodegradability compared to conventional methods. Microbial community analysis also indicated that the genus Desulfovibrio and Enterobacter contributed to the biodegradation of P34HB films and the electrical signals production via the cooperation among other microorganisms. This study presented the online monitoring of the anaerobic biodegradation of P34HB films through MFC-based sensors, which provided an alternative approach to evaluate the anaerobic biodegradability of biodegradable plastics.

Understanding Plastic Bag Consumption and Management in Thailand: Integrating a KAP Model

Since January 1, 2020, Thailand has implemented a campaign to stop giving free single-use plastic bags in 75 major retail stores. This study aims to (1) understand the status quo and effectiveness of the plastic bag ban campaign by estimating the number of plastic bags used in Bangkok and Phuket (2) understand the consumers’ behavioural on plastic bag consumption and management by integrating a knowledge, attitude, and practice (KAP) model (3) provide policy recommendation to strengthen the country plastic waste management roadmap. The results showed that the ban on plastic bag campaign is effective, especially in the supermarkets and convenience stores in Bangkok. The numbers of plastic bags used per visit at supermarkets and convenience stores are approximately 1.9 bags and 1.7 bags, respectively, whereas the plastic bags used at fresh markets, restaurants, and food delivery services are, on average, up to 3.7, 3.1, and 2.8 bags per visit, respectively. On average, people in Bangkok use approximately 1.2 bags/person/day, while only 0.7 bags/person/day are used in Phuket. According to the KAP model, attitude is more crucial than knowledge towards pro-environmental behaviour. Bangkok residents’ trend to show more pro-environmental behaviour than Phuket residents. For policy implication, it is important to continuously communicate the environmental impact of plastics and emphasise the proper knowledge and attitudes toward plastic bags among people to encourage their cooperative behaviours in reducing the use of plastic bags and sorting waste for recycling.

Effects of operating conditions on supercritical methanol liquefaction of polypropylene

Plastic waste has grown at a dramatical rate over recent years, resulting in an emerging global environmental issue of white pollution. However, it also represents a potential and untapped resource for its rich carbon and hydrogen content. This work converts plastic waste into high quality oil by employing supercritical methanol. Polypropylene was liquefied at the temperature range of 330–400 °C and reacting time of 0–70 min to evaluate the effect of temperature and time on liquefaction. The results show that both increasing temperature and reaction time could promote PP conversion, thus increasing oil yield. Among parameters tested, conversion rate could achieve as high as 95.2 % at 390 °C for 70 min. Hydrocarbons and oxygenates were main compounds in the oil according to GC-MS. Reaction time led a slight difference in the oil composition while temperature led more significant variation. 72.83 % and 71.55 % of hydrocarbon in oil were obtained at 390 °C for 60 min and at 370 °C for 0 min, respectively. With temperature and time increasing, long chains were further cracked into short chains and the carbon distribution of oil became more concentrated, thus improving oil quality. These results imply that supercritical methanol could work well as a solvent to liquefy plastic into high quality oil, which provides a feasible way to solve the plastic pollution.

Converting waste expanded polystyrene into higher-value-added hyper-crosslinked porous polymer for rapid and high-efficient adsorption of aflatoxins

White pollution caused by the massive discharges of waste expanded polystyrene (WEPS) has become a critical global issue, so the effective conversion of WEPS is of great significance to reduce white pollution. Herein, adopting WEPS as raw material, three high-value-added hyper-crosslinked polymers (WEPS-HCPs) with high surface areas and abundant micro/mesoporous structures were synthesized via Friedel-Crafts alkylation reaction using dimethoxymethane, dichloroxylene and 4,4′-bis(chloromethyl)-1,1′-biphenyl (BCB) as cross-linker, respectively. The WEPS-HCPs were used as sorbent to extract aflatoxins (AFs) and all the HCPs exhibited high adsorption capacity. For the fast separation and recovery of the sorbent, WEPS-BCB was chosen as a model HCP to be magnetically functionalized to obtain a magnetic HCP (mWEPS-BCB) for the first time. Based on magnetic solid phase extraction with the mWEPS-BCB as sorbent, a fast and sensitive method was developed to determine trace level of AFs in grain food. Under the optimal conditions, the proposed method presented wide linear range (0.008–10.0 ng g−1), low detection limit (0.002–0.015 ng g−1) and satisfactory precision (relative standard deviation < 7%). Converting WEPS into a high-value-added sorbent not only provided a facile strategy for effective recycling of WEPS, but also developed a sensitive method for accurate determination of AFs in grain food, achieving significant economic and environmental benefits.

Tuning the surface hydrophilicity of a C3N4 nanosheet for efficient photocatalytic H2 evolution coupled with microplastic degradation

Simultaneously realizing highly-efficient degradation of microplastics coupled with H2 evolution is urgently demanded to solve the white pollution and energy shortage issues. Herein, we fabricate a series of fragmented hydrophilic homogeneous carbon nitride (TP-PCN) by terminating the polymerization of carbon nitride using iodide ions (I−), which acts as an invisible inhibitor by breaking the π-π bond to reduce the accumulation of ultra-thin layers in PCN to inhibit the polymerization. The H2 evolution rate of resultant photocatalyst could reach 600.3 μmol g−1 h−1 in alkaline polyethylene terephthalate (PET) solution, exhibiting outstanding photocatalytic activity. Meanwhile, the PET was also degraded into small molecules, which were used in agricultural production, food processing and pharmaceuticals. The high photocatalytic activity of the TP-PCN photocatalyst can be ascribed to the promoted hydrophilicity and charge separation ability. This work supplies new insights for the design of functional photocatalysts and developing green technologies to solve environment pollution.

The implementation effects of different plastic bag ban policies in China: the role of consumers’ involvement

This study selects three cities in China that implement plastic bag ban policies with different levels of consumer involvement to compare the effects of policy implementation. In general, consumer plastic bag usage behaviour becomes more environmentally friendly when plastic bag ban policies became more stringent. High consumer involvement policies induces changes in pro-environmental bag use; however, their plastic-reducing effects are uncertain and compounded. In contrast, low-consumer-involvement policies could reduce plastic waste damage but could not make consumers’ more environmentally conscious with regard to bag usage. Moreover, this study confirms robust bag usage differences across different groups of consumers. These findings provide valuable insights into the patterns of influence of different types of plastic bag bans. Based on these insights, plastic crisis managers can create more effective and targeted policies to combat the growing plastic crisis.

A novel sol-gel strategy for constructing wood fibers and aramid nanofiber nanocomposite with strong, tough and recyclable properties

Recently, biomass-based materials derived from wood processing residues have been developed to resolve the white pollution. However, the poor mechanical strength, weak water resistance, and non-recyclability still limit their practical applications. Aramid nanofiber (ANF) is a promising reinforcement due to the unique structural characteristics and exceptional mechanical properties. Here, a high-performance wood fibers-based nanocomposite was assembled based on chemically-modified wood fiber (CWF) and ANF via a sol-gel strategy with the solvent exchange. The dynamic noncovalent cross-linking with 3D reticular networks between CWF and ANF endow the as-prepared film with high tensile strength of 591.96 ± 11.05 MPa, high toughness of 38.68 ± 2.15 MJ/m3, and excellent solvent resistance. Moreover, the CWF-ANF gel can effectively repair the fractured CWF-ANF film under heating and maintain competitive mechanical properties after several dissolution-reconstruction, which shows the fascinating sustainability potential. Simultaneously, the as-prepared film is considered as a strong substrate to advance excellently conductive and anti-counterfeiting composite with double-layered structures. This effective strategy provides a novel pathway to reuse plant waste resources with competitive mechanical properties and high value-added utilization.

Catalytic Amounts of an Antibacterial Monomer Enable the Upcycling of Poly(Ethylene Terephthalate) Waste.

Poly(ethylene terephthalate) (PET) is an important polymer with an annual output second only to polyethylene. The development of PET recycling technologies is therefore necessary to not only eliminate the harm associated with white pollution and microplastics, but also to reduce carbon emissions. Antibacterial PET, one of the most high-value advanced materials, has improved the ability to treat bacterial infections. However, current methods of manufacturing commercial antibacterial PET require blending with an excess of metal-based antibacterial agents, which leads to biotoxicity and a nonpersistent antibacterial activity. In addition, high-efficiency organic antibacterial agents have yet to be employed in antibacterial PET due to their poor thermal stabilities. Herein, a solid-state reaction for the upcycling of PET waste using a novel hyperthermostable antibacterial monomer is described. This reaction is catalyzed by the residual catalyst present in the PET waste. It is found that a catalytic amount of the antibacterial monomer enabled the low-cost upcycling of PET waste to produce high-value recycled PET with a strong and persistent antibacterial activity, as well as similar thermal properties to the virgin PET. This work provides a feasible and economic strategy for the large-scale upcycling of PET waste and exhibits potential for application in the polymer industry.

Base- or acid-assisted polystyrene plastic degradation in supercritical CO2.

The online version contains supplementary material available at 10.1007/s42768-023-00139-1.

The Devastation of Waste Plastic on the Environment and Remediation Processes: A Critical Review

The devastating effect of plastic waste on the ecosystem due to the rapid increase in population has been a concern. Although stakeholders and governments invested in efforts to mitigate plastic waste, their exertions have limited to no effects as the demand for plastic increases annually. Emerging practical advancements in recycling plastic have been critical for achieving a sustainable circular economy. This study reviews the adverse effect of plastic waste on the environment and the inhabiting creature, the regulation for managing plastic waste, and their limitations. This scoping review also provides information on the current route for reducing plastic waste by defining its sources and their applications. After identifying the generation of plastic waste, the plastic polymers are categorized according to the hazard ranking of their monomers according to their environmental toxicity, damaging the inhabiting creature. The discharge pathways of plastic waste into the environment and aquatic systems leading to white pollution and climate change were also determined. Conversion of plastic waste through the remedial channel by manufacturing value-added products using techniques such as reusing, recycling, and energy recovery, reducing the disposal of plastic waste in landfills is outlined. The information on remedial processes provided in this study will help reduce plastic waste from the environment. In addition, correctly applying these suggestions may help reduce environmental pollution and the death of inhabiting creations. Further research is necessary to convert plastic waste as raw materials into high-value products to achieve a circular economy.

Mechanism and characterization of microplastic aging process: A review.

With the increasing production of petroleum-based plastics, the problem of environmental pollution caused by plastics has aroused widespread concern. Microplastics, which are formed by the fragmentation of macro plastics, are bio-accumulate easily due to their small size and slow degradation under natural conditions. The aging of plastics is an inevitable process for their degradation and enhancement of adsorption performance toward pollutants due to a series of changes in their physiochemical properties, which significantly increase the toxicity and harm of plastics. Therefore, studies should focus on the aging process of microplastics through reasonable characterization methods to promote the aging process and prevent white pollution. This review summarizes the latest progress in natural aging process and characterization methods to determine the natural aging mechanism of microplastics. In addition, recent advances in the artificial aging of microplastic pollutants are reviewed. The degradation status and by-products of biodegradable plastics in the natural environment and whether they can truly solve the plastic pollution problem have been discussed. Findings from the literature pointed out that the aging process of microplastics lacks professional and exclusive characterization methods, which include qualitative and quantitative analyses. To lessen the toxicity of microplastics in the environment, future research directions have been suggested based on existing problems in the current research. This review could provide a systematic reference for in-depth exploration of the aging mechanism and behavior of microplastics in natural and artificial systems.

Johansen cointegration of frequency response functions contaminated with nonstationary colored noise for structural damage detection

This study proposes an effective damage detection method for laminated composite structures under the influence of nonstationary colored noise using condensed Frequency Response Functions (CFRFs) as damage-sensitive features (DSF). For structural health monitoring (SHM), the effect of FRF contamination with stationary white noise has primarily been explored for stationary white noise pollution, with only a few studies investigating contamination with highly correlated nonstationary colored noise, e.g., Brown noise. In the investigation, CFRFs are contaminated with signal noise produced by Brownian motion of two different signal-to-noise ratios, i.e., 20 and 10. This contamination leads to nonstationary patterns, which present a challenge for vibration-based damage detection. Therefore, in this study, a robust method based on Johansen cointegration – a concept from the field of econometrics – is developed. The proposed method aims at deriving a stationary representation of nonstationary measured CFRF signals to be subsequently fed into a sensitivity-based model-updating problem. To validate the method, it is applied to numerical examples of laminated composite plates with different numbers of ply orientations. The superior capabilities of the proposed method are demonstrated by comparing it against two state-of-the-art methods from the literature and a method based on the Sum of Unwrapped Instantaneous Hilbert Phase (SUIHP) of CFRFs previously developed by the authors. A novel metric based on the notion of mutual information is proposed to decipher why exactly the proposed method is superior to its preceding alternative. The results show that the new DSF can capture significantly more information from noisy CFRFs than the previously developed DSF. As such, for half of the cases, the proposed DSF was able to capture more than 80% of information from the colored-noisy CFRFs. This is in contrast to the previously developed method that can only capture less than 40% of information for all the cases.

Distinct distribution patterns and functional potentials of rare and abundant microorganisms between plastisphere and soils

The increasing application of plastic film has caused the “white pollution” of farmlands in greenhouses. To date, most studies on the ecology of the plastisphere have focused on the whole microbial community, with few on the rare and abundant taxa, especially in the terrestrial ecosystems. To understand the plastisphere rare and abundant taxa of bacterial and fungal communities, we collected residues of plastic film from plastic-covered soils in the greenhouse. The plastisphere was significantly different from surrounding soils in terms of alpha- and beta-diversities of abundant and rare taxa. Such discrepancies were greater in rare taxa than in abundant taxa. Besides, the enrichment of soil-borne plant pathogenic fungi in the plastisphere implied that plastic film residues can act as vectors for pathogen transmission. In the plastisphere, the stochastic process governed the assemblies of rare taxa, while deterministic assemblies dominated that of abundant taxa. However, in surrounding soils, the stochastic process played a larger role in abundant taxa as compared to rare taxa. The plastisphere showed a network of less complexity, more competitive connections, and more modules compared to surrounding soils, and rare taxa played greater roles than abundant taxa. There existed obvious discrepancies in the microbial functions between surrounding soils and plastisphere, including carbon, sulfur, nitrogen, and phosphorus cycling, and rare taxa contribute large proportions to the above cycling processes. Altogether, the findings advance our understanding of ecological mechanisms of abundant and rare taxa in the plastisphere in terrestrial ecosystems.

A State-of-the-Art Review on the Technological Advancements for the Sustainable Management of Plastic Waste in Consort with the Generation of Energy and Value-Added Chemicals

Plastic waste poses a serious threat to the environment and it has been increasing at an alarming rate. In 2022, global plastic waste generation was reported to be around 380 million tonnes as compared to 353 million tonnes in 2019. Production of liquid fuel from plastic waste is regarded as a viable method for disposing of the plastic and utilizing its energy. Currently, a wide range of technologies have been explored for turning plastic waste into fuel, including the conventional pyrolysis, incineration, gasification and advanced oxidation. However, a systematic summary and comparative analysis of various technologies has still not reported. Traditional non-biodegradable plastic waste (NPW) treatment methods include landfilling and incineration, but these methods encounter bottlenecks and are unable to adequately address NPW issues. This review attempts to present a thorough summary of treatment methods for plastic waste (both conventional and novel treatment technologies that have recently been reported), examine their mechanism and their current state of development. Furthermore, the superiority and drawbacks of each technology are analysed and the prospects of technology application are proposed. By tackling the problems of white pollution and energy scarcity, this review intends to inspire the use of solid waste as a source of energy.

Simulating polyethylene pyrolysis from a generalized molecular-level kinetic model

Waste plastics have emerged as a global environmental issue. Polyethylene, accounting for about 25% of global plastic production, has been acknowledged as the major cause of “white pollution”. In this paper, a generalized molecular-level kinetic model was proposed to understand the pyrolysis of polyethylene applying structure-oriented lumping, Poisson distribution, and genetic algorithm. The number of ordinary differential equations derived from the reaction kinetics were dramatically reduced by this simplified network with 14-rule design. The generalizability was confirmed by case studies without any change in the rule design. Under most conditions, the mean relative error between experimental and model data could be controlled within 5%, while abnormal deviations indicate the obstacle of heat transfer. The simulation curve could provide guidance for the experiments by locating the peak value of products. From 400–470 °C in Case 2, the increase in the reaction proportion of producing light oil explains the experimental results from the perspective of molecular-level reaction network. The comparison between PE and PS pyrolysis elaborates different pyrolysis mechanisms based on the different molecular structures.

Binary asteroid scattering around white dwarfs

ABSTRACTIncreasing observations of white dwarf atmospheric pollution and disrupting planetesimals is driving increased studies into the fate of exo-asteroids around post-main-sequence stars. Planetesimal populations in the Solar System that are most likely to survive the violent post-main-sequence evolution, such as the Kuiper Belt, display a large binary fraction with a propensity for near equal-mass components and provide a previously unexplored population of planetesimals that are likely to exist around white dwarfs. Here, we simulate the dynamical evolution of equal-mass binary asteroid systems around white dwarfs using the N-body integrator REBOUND for 1 Gyr. We confirm that giant planets are efficient at dissociating and ejecting binary asteroid systems on eccentric orbits, while Earth-mass planets are better at keeping planetesimals in their planetary systems. We find binary systems can be dissociated and ejected from their systems across Myr time-scales, producing interstellar objects. We do not expect a population of free-floating binary asteroid systems as all ejected planetesimals are gravitationally unbound from each other. Further, we discuss the influence of asteroid binarity on the white dwarf pollution process and find there is little to no impact on how close a body can get to a star. However, the orbital evolution of binary asteroids changes the distribution of planetesimals available in a white dwarf planetary system to be further scattered onto white dwarf polluting orbits.

Comparing two types of mainstream disposable lunch boxes by LCA and exploring the possibility of converting carbon dioxide into products

BackgroundA disposable lunch box is an important cause of “white pollution”. Many people consider that the disposable polylactic acid (PLA) lunch box is more environmentally friendly than the disposable paper pulp lunch box and can substitute for the latter. ObjectiveWe can determine whether PLA tableware is more environmentally friendly than paper tableware by analyzing the product life cycle of two tableware types. At the same time, as a continuous compound, carbon dioxide has significant commercial value. Carbon dioxide materials' applications range from beverages to cosmetics and building materials. The future application of carbon dioxide in the field of lunch boxes is discussed in this paper. MethodsIn this paper, the production stages of the two types of disposable lunch boxes were compared and surveyed using the life cycle assessment (LCA) method. ConclusionThe results reveal that the main impact of the two types of lunch boxes is resource damage; the PLA lunch box is not better than the paper type; the production stage of the disposable PLA lunch box poses greater damage to the environment in all aspects than the paper type. DiscussionAgainst the background of carbon neutrality and based on the constantly mature carbon dioxide conversion technology, the author explored the possibility of making products from carbon dioxide and proposed to make product designs based on carbon dioxide.

Ball-Milling Preparation of La3+/TiO2 Photocatalyst and Application in Photodegradation of PVC Plastics

The fact that the use of a large number of plastic products has brought serious pollution to the environment has always been the focus of global attention. The development of photocatalytic degradable plastics is one of the effective ways to solve the problem of “white pollution”. In this work, La3+ modified TiO2 nanoparticles were prepared by ball milling and characterized. La3+/TiO2 was mixed with Polyvinyl chloride (PVC) plastic to make a photodegradable composite film, and the photodegradation performance and mechanical properties of films were evaluated. The photodegradable films were characterized by infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). After 30 h UV irradiation, the weight loss rate of the PVC was only 2.12%, while that of the TiO2/PVC reached 8.94%. The accelerating of the degradation rate was due to the mixing of TiO2 into PVC. As for the La3+/TiO2/PVC composite film, when the mass percentage of La3+/TiO2 was 1.5%, the weight loss rate of La3+/TiO2/PVC sample reached a maximum of 17.78%, which was eight times the degradation rate of PVC and two times the degradation rate of TiO2/PVC. The La3+/TiO2/PVC film showed good photodegradability. La is a transition metal element with a special 4f electronic structure. The reaction mechanism of photodegradation of PVC by the interaction of La3+ and TiO2 were discussed.

Ecological technology of green building in the initial stage of design based on BIM technology

At present, the whole world is faced with a common topic, that is, the contradiction between energy consumption, serious fog, the continuous rise of PM2.5, plastic waste, white pollution and other environmental pollution and the worldwide energy shortage. In this paper, aiming at the international new town construction project in Xigu District, Lanzhou, Revit software is used to establish a physical model for data integration and integrated management of the geometric information of building space, functional information of building space, building materials and other related data information of the project, and an analysis model for the scheme design of the residential building of the project is obtained, and ecological and technical factors such as energy consumption analysis, lighting analysis, indoor lighting analysis, solar radiation analysis, shading and thermal comfort analysis of the project location are analyzed. The research shows that the thermal performance, energy consumption simulation analysis and hourly heat gain/loss analysis of the envelope in the coldest weather in the local area show that the heat conduction of the envelope is small under the three conditions of structural design (case A), standard limit (case B) and hypothetical construction (case C), which indicates that the solar radiant heat is mainly related to the material performance of the external window when the heat transfer coefficient of the roof is close, and the heat gain and loss between regions has little change.

Incorporation of ultrathin porous metal-free graphite carbon nitride nanosheets in polyvinyl chloride for efficient photodegradation

Solid-phase photocatalytic degradation of waste plastics is one of the promising approaches to solve the “white pollution” problem. In this work, a low cost, metal-free, environmentally friendly organic photocatalyst, graphite carbon nitride (g-C3N4), was used for the first time to successfully enhance the photodegradation of polyvinyl chloride (PVC) under simulated sunlight from its visible light photocatalytic capability, while its organic nature and abundant surface functional groups were beneficial for its good dispersion in plastics. It was found that the ultrathin porous g-C3N4 nanosheet synthesized from urea (the UCN sample) had much stronger photodegradation effect in PVC/g-C3N4 composite films than its thick block counterpart synthesized with melamine (the MCN sample) due to its larger specific surface area, higher pore volume, and enhanced photogenerated charge carrier separation. With the incorporation of only 1 wt% UCN sample into PVC, its mechanical properties were largely enhanced with the tensile strength increase of ∼ 45% and the elongation at break increase of ∼ 72%, and its weight loss increased ∼ 58% after 120 h irradiation in the weather resistance test chamber. ·O2- and h+ produced by the UCN sample were found as the main active species in the photocatalytic degradation of PVC to dechlorinate PVC and decompose its long-chain molecules into short-chain small molecules until its final degradation into CO2 and H2O under ideal conditions.