Production Of Biodegradable Plastics Research Articles

Hydrogen Bond-Mediated Strong Plasticization for High-Performance Alginate Plastics.

The increasingly severe plastic pollution has urged an inevitable trend to develop biodegradable plastic products that can take over synthetic plastics. As one of the most abundant natural polymers, polysaccharides are an ideal candidate to substitute synthetic plastics. The rigidity of polysaccharide chains principally allows for high strength and stiffness of their materials, however, challenges the facile orientation in material processing. Here, a general hydrogen bond-mediated plasticization strategy to regulate isotropic sodium alginate (SA) chains to a highly ordered state is developed, and alginate plastics with high performances are fabricated. It is revealed that hydroxyl groups in glycerol modulate the viscoelasticity of SA solids by forming strong hydrogen bonds with SA chains, achieving a large stretchability at a high solid content. Highly orientated alginate films exhibit a superior tensile strength of 575MPa and toughness of 60.7MJ m-3, outperforming most regenerated biomass films. The high solid content and large stretchability mediated by strong hydrogen bonding ensure plastic molding of solid-like SA with high fidelity. This hydrogen bond-mediated plasticity provides a facile but effective method to justify the high performances of polysaccharide-based plastics.

Elucidating the atomic stacking structure of nickel phyllosilicate catalysts and their consequences on efficient hydrogenation of 1,4-butynediol to 1,4-butanediol

The hydrogenation of 1,4-butynediol (BYD) to 1,4-butanediol (BDO) plays a pivotal role in the production of biodegradable plastics, including PBAT and PBS. Herein, we prepared a range of nickel phyllosilicate catalysts with diverse atomic stacking configurations for the direct synthesis of BDO via BYD hydrogenation. In comparison to conventional supported Ni catalysts, the metal sites derived from nickel phyllosilicate demonstrated remarkable hydrogenation activity for the conversion of CC-C-OH alkynol to C-C-C-OH alkanol. Both the physical structures and -importantly- chemical properties of these catalysts were crucial for product selectivity and yield; and a BDO yield of 93.4 % with complete conversion of BYD was achieved at 50 °C and 1 MPa H2 over the Niphy@SiO2-UDP catalyst with a pure 1:1 Ni phyllosilicate structure. Kinetic experiments and theoretical calculations confirmed that the initial hydrogenation of BYD to 1,4-butenediol (BED) was the rate-determining step for the saturated hydrogenation to BDO. The metallic Nisite is responsible for the dissociation of hydrogen, while due to the enhanced synergism derived from the 1:1 atomic stacking phyllosilicate structure, a type of cooperated Ni-Niδ+-acid sites can stabilize the CC electron cloud over the carbon chain of BED intermediate, hence benefiting its further hydrogenation, and suppressing its isomerization to undesired aldol condensation byproduct. Our findings provide valuable insights into the atomic stacking structures of metal phyllosilicate catalysts, revealing the micro-environment of chemical properties and interactions that govern the state/activity of Ni species, which is helpful for the rational design of other hydrogenation catalysts with enhanced performance.

Taguchi approach for assessing supercritical CO2 (sCO2) fluid extraction of polyhydroxyalkanoate (PHA) from Chlorella Vulgaris sp. microalgae

This research explicitly investigates the utilization of Chlorella Vulgaris sp. microalgae as a renewable source for lipid production, focusing on its application in bioplastic manufacturing. This study employed the supercritical fluid extraction technique employing supercritical CO2 (sCO2) as a green technology to selectively extract and produce PHA's precursor utilizing CO2 solvent as a cleaner solvent compared to conventional extraction method. The study assessed the effects of three extraction parameters, namely temperature (40–60 °C), pressure (15–35 MPa), and solvent flow rate (4–8 ml/min). The pressure, flowrate, and temperature were found to be the most significant parameters affecting the sCO2 extraction. Through Taguchi optimization, the optimal parameters were determined as 60 °C, 35 MPa, and 4 ml/min with the highest lipid yield of 46.74 wt%; above-average findings were reported. Furthermore, the pretreatment process involved significant effects such as crumpled and exhaustive structure, facilitating the efficient extraction of total lipids from the microalgae matrix. This study investigated the microstructure of microalgae biomatrix before and after extraction using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Fourier-transform infrared spectroscopy (FTIR) was utilized to assess the potential of the extracted material as a precursor for biodegradable plastic production, with a focus on reduced heavy metal content through inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis. The lipid extracted from Chlorella Vulgaris sp. microalgae was analysed using gas chromatography-mass spectrometry (GC-MS), identifying key constituents, including oleic acid (C18H34O2), n-Hexadecanoic acid (C16H32O2), and octadecanoic acid (C18H36O2), essential for polyhydroxyalkanoate (PHA) formation.

Mimicking real-field degradation of biodegradable plastics in soil and marine environments: From product utility to end-of-life analysis

Biodegradable plastics can mitigate plastic waste issues by undergoing hydrolysis and microbial digestion. However, biodegradable plastics face unjust accusations of not decomposing in natural environments, including barren soil or cold oceans, under unsuitable conditions. In this study, we simulated end-of-life of biodegradable plastic products under real-field soil and seawater conditions. Replenishing vermicompost in horticultural topsoil (3:7 wt ratio) activated microbial growth, resulting in significant degradation. In fertile soil, polycaprolactone (PCL) and poly(butylene succinate) (PBS) required fewer than 6-months, for complete degradation, while poly(butylene adipate-co-terephthalate) (PBAT) with more than 51 mol% terephthalate content was rarely degraded. In an artificial seawater aquarium, PCL degraded at the rate of 30 μm per month. The degradation of bioplastics enclosed in coarse nets was superior to that in fine nets, owing to higher aeration and water circulation. Sea waves and current significantly accelerated the rate of PCL-degradation to 89 μm per month in a coastal marine environment; the ranking of rate of decomposition was PCL > PBS > PBAT. After 12 months of biodegradation, the tensile strength and elongation of a 2 mm-thick sample of PCL decreased to 15 MPa and almost 0 %, respectively. 3D-printed jars, designed for octopus fishing, is widely used and its designed mechanical decay aids in preventing the ghost fishing of abandoned gear as demonstrated by artificial conches, illustrating the potential for biodegradable fishing gear.

Assessing the adverse impacts of biodegradable plastic bags: Chemical elements and radionuclides considerations

Biodegradable plastic (BP) products are considered potential substitute for conventional plastics and are increasingly used in various fields and applications. However, concerns remain regarding their safety and potential impact on the humans and ecosystems. This research examined pristine BP shopping bags (collected from local market in Jeddah, Kingdom of Saudi Arabia) for their elemental content and natural radionuclides, 40K, Th, and U, using neutron activation analysis. The results obtained revealed that BP bags contain higher mass fractions of potentially toxic elements (e.g., Cr, Co, Ba, Zn, Mn, V, Cd, Mo), halogens (Br and Cl), and natural radionuclides compared to conventional plastic bags. To assess the potential human health risks associated with BP shopping bags, the radiological and elemental hazards were evaluated by calculating the relevant hazard indices over a long exposure period. For non-carcinogenic risks, the average daily intake of each element through different exposure pathways, as well as the hazard quotient, hazard index, and total exposure hazard index, were estimated. For carcinogenic risks, the incremental lifetime cancer risk was calculated. Possible hazards arising from radiological exposure were assessed by determining the excess lifetime cancer risk and other indices. Overall, the results showed that BP bags don’t pose a significant radiological or elemental threat to human health. However, attention should be given for controlling and monitoring the Cr content in BP bags. For more accurate health risk assessment, studies on leaching of chemical elements and radionuclides under different environmental and biological conditions will be carried out in future works.

Poly-β-hydroxybutyrate production by Synechocystis MT_a24 in a raceway pond using urban wastewater.

Poly-β-hydroxybutyrate (PHB) is a potential source of biodegradable plastics that are environmentally friendly due to their complete degradation to water and carbon dioxide. This study aimed to investigate PHB production in the cyanobacterium Synechocystis sp. PCC6714 MT_a24 in an outdoor bioreactor using urban wastewater as a sole nutrient source. The culture was grown in a thin-layer raceway pond with a working volume of 100 L, reaching a biomass density of up to 3.5g L-1 of cell dry weight (CDW). The maximum PHB content was found under nutrient-limiting conditions in the late stationary phase, reaching 23.7 ± 2.2% PHB per CDW. These data are one of the highest reported for photosynthetic production of PHB by cyanobacteria, moreover using urban wastewater in pilot-scale cultivation which multiplies the potential of sustainable cultivation approaches. Contamination by grazers (Poterioochromonas malhamensis) was managed by culturing Synechocystis in a highly alkaline environment (pH about 10.5) which did not significantly affect the culture growth. Furthermore, the strain MT_a24 showed significant wastewater nutrient remediation removing about 72% of nitrogen and 67% of phosphorus. These trials demonstrate that the photosynthetic production of PHB by Synechocystis sp. PCC6714 MT_a24 in the outdoor thin-layer bioreactor using urban wastewater and ambient carbon dioxide. It shows a promising approach for the cost-effective and sustainable production of biodegradable carbon-negative plastics. KEY POINTS: • High PHB production by cyanobacteria in outdoor raceway pond • Urban wastewater used as a sole source of nutrients for phototrophic growth • Potential for cost-effective and sustainable production of biodegradable plastics.

Agricultural resources in focus: Eco-friendly bioplastic synthesis from corn starch

The current research focuses on the development of bioplastics from agricultural resources like banana peels, potato peels and corn starch. The specific focus here is the utilization of agricultural resources into bioplastics as an eco-friendly alternative to conventional plastics. The main objective of this research is to explore the manufacturing of biodegradable plastics by utilizing these materials. The formation of bioplastics from banana and potato peels is not as successful, while notably consistent formation for bioplastics derived from corn starch. The additional research has been conducted on corn starch based bioplastic films. The impact of various glycerol amounts (0.2 g to 0.8 g) was studied concerning the measurement of tensile strength (1.52 MPa to 5.08 MPa) in corn starch-derived bioplastics. The physico-chemical properties, availability of FT-IR functional groups (C-O-H, O-H, C-H, C = O, CONH, C-O, and C-O-C) and SEM analysis are confirming bioplastic films surface derived from corn starch and compared to existing literature. Furthermore, the research includes solubility and biodegradability tests were determined the most suitable and preferred agricultural resources for biodegradable plastic production.

Application And Research of Biodegradable Plastics in China and The United States

In this era of continuous economic growth, an increasing number of people have shifted their focus towards acquiring more convenience and benefits, thereby reducing their level of concern for the environment, ultimately giving rise to various forms of environmental pollution. Among these pollutants, the closest to us is "white pollution," which refers to a series of harms caused by non-degradable plastics. As one of the most essential materials in people's daily lives, plastics are virtually irreplaceable by other materials. Therefore, this paper will delve into the necessity and feasibility of using biodegradable plastics. It will further compare and analyze China and the United States' attitudes, specific policies, and industrial manufacturing status regarding biodegradable plastics. This paper, through an examination of relevant literature, national laws, policies, and data collection and analysis, identifies the differences between China and the United States in their attitudes and policies towards biodegradable plastics. It also analyzes the strengths and weaknesses of both countries in the biodegradable plastics market and production technology. Finally, it briefly assesses the prospects and outlook for both countries in the field of biodegradable plastics and environmental governance.

Metabolic engineering of Escherichia coli for efficient production of 1,4-butanediol from crude glycerol

1,4-butanediol (1,4-BDO) is a significant non-natural chemical with diverse applications in various fields, particularly in the production of biodegradable plastic products as an essential monomer. The conversion of starch-based sugars using microbial cell factories provides a green alternative for the production of 1,4-BDO, but was limited by the low efficiency and high production cost. In this work, the classic CoA-dependent 1,4-BDO synthesis pathway was exogenously introduced into Escherichia coli, but the titer of 1,4-BDO was only 0.72 g/L using glucose as the substrate. The poorly expressed enzymes and the ineffective distribution of central carbon flux were considered the main limiting factors. Combined genetic manipulation of the synthesis pathway and bioprocess engineering, glycerol was proven to be a more favorable feedstock for 1,4-BDO synthesis, and a novel pathway functioned by carboxylic acid reductase could achieve one-step catalysis from 4-hydroxybutyric acid to 4-hydroxybutyraldehyde, which avoided the rate-limiting steps involved by hydroxybutyrate CoA transferase (Cat2) and alcohol dehydrogenase (Bld). The titer of 1,4-BDO reached 1.31 g/L and 1.07 g/L in the novel pathway using pure glycerol and the industrial by-product crude glycerol as the substrate, respectively. The fed-batch fermentation was finally conducted, and the titer of 1,4-BDO was increased to 5.75 g/L with a yield of 143.75 mg/g glycerol. Our work removed the bottleneck of the 1,4-BDO synthesis pathway by introducing carboxylic acid reductase and effectively converted crude glycerol to 1,4-BDO, which enabled us to build a sustainable microbial cell factory to cost-efficiently produce 1,4-BDO as well as other biochemicals from crude glycerol.

Polyhydroxyalkanoate production from food packaging waste paper

This study evaluated the production of marine biodegradable plastics, specifically polyhydroxyalkanoates (PHAs), using waste paper from food containers as a novel material source. The results showed that adding dilute sulfuric acid as a pretreatment may have a negative impact on enzyme hydrolysis efficiency. Without pretreatment, the highest glucose concentration was observed in the 50-min heating group. In the experimental group with 1% dilute sulfuric acid as a pretreatment, the highest average glucose concentration was observed in the 25-min treatment group. In flask scale experiments, the C/N ratio was controlled at 10, 20, and 30. The results showed that when the C/N ratio was 10, the PHA/CDM ratios were 16.3 and 23.6 at 48 and 72 h, respectively. After 96 h of cultivation using hydrolysis liquid from the waste paper container as the sole carbon source in a 5-L scale experiment, the PHA/CDM ratio was 28.7 and the PHA concentration was 0.95 g/L. The potential bacterial strain in this study was confirmed to be a Bacillus genus bacterium after strain identification. The signal peaks indicated that the PHA obtained from the Bacillus sp. production process was PHB.

Preparation of bioplastic film from chitosan and mango (Mangifera Indica L. Anacardiaceae) kernel starch by casting method

The accumulation of plastics in landfills and oceans has encouraged the development of biodegradable plastic products from renewable sources. Natural polymers are excellent candidates that need further modification of their functional and structural properties comparable to conventional plastics. This study aims to fabricate and optimize the formulation of bioplastic films from chitosan and mango kernel starch with glycerol as a plasticizer using response surface methodology (RSM). The chitosan-to-starch mass ratio (1:0.17 to 1:5.83) and glycerol concentration per gram of dry polymer (15.86% to 44.14%) were assigned as the independent variables to design an empirical model that describes the films’ elastic modulus as the sole response. The results yielded an optimal formulation of 1:0.17 chitosan-to-starch mass ratio (2% weight by volume chitosan solution blend) with 15.86% glycerol (per gram of dry chitosan and starch). Reproduction of the optimized film was carried out to validate the empirical model. Characterization of the films’ mechanical and barrier properties, surface morphology, and biodegradability were also investigated in this work. The results suggest that the functional properties of the bioplastic film surpass other chitosan-based bioplastic film blends and can be developed further to become a more sustainable alternative to conventional plastic packaging products.

Research on biodeteriotration of plastics

Plastics and microplastics are attracting increasing public attention due to their wide occurrence in the environment and accumulation in plants, wildlife and humans. In addition to the vast quantity of packaging plastics discharged into the municipal waste stream, an increasing volume of industrial polymeric materials from the electronics industry, space and aviation is also accumulating in the environment. This latter group of materials has received far less attention than it deserves, including toxicological studies. The goals of engineers and materials scientists are to create materials with high durability and exceptional performance, but these are properties that prevent degradation occurring, at least within the designed life span. The public perception is that production of degradable and biodegradable plastics can reduce the negative environmental impacts from these materials. However, another feasible option is to enhance the non-degradability of these functional polymers and hence extend their life span to reduce wastes from their application. Microbial colonization and deterioration of these materials seriously affects their design properties. The most significant challenge is on the fate of industrially produced, mechanically strong, and chemically inert plastics and polymeric materials after disposal at the end of their service life. Biodegradation is the specific focus of this review, and we will discuss the current knowledge and key research questions that remain to be answered.

Replacing Traditional Plastics with Biodegradable Plastics: Impact on Carbon Emissions

In recent years, a great deal of attention has been focused on the environmental impact of plastics, including the carbon emissions related to plastics, which has promoted the application of biodegradable plastics. Countries worldwide have shown high interest in replacing traditional plastics with biodegradable plastics. However, no systematic comparison has been conducted on the carbon emissions of biodegradable versus traditional plastic products. This study evaluates the carbon emissions of traditional and biodegradable plastic products (BPPs) over four stages and briefly discusses environmental and economic perspectives. Four scenarios—namely, the traditional method, chemical recycling, industrial composting, and anaerobic digestion—are considered for the disposal of waste biodegradable plastic product (WBBPs). The analysis takes China as a case study. The results show that the carbon emissions of 1000 traditional plastic products (plastic bags, lunch boxes, cups, etc.) were 52.09–150.36 carbon emissions equivalent of per kilogram (kg CO2eq), with the stage of plastic production contributing 50.71%–50.77%. In comparison, 1000 similar BPPs topped out at 21.06–56.86 kg CO2eq, approximately 13.53%–62.19% lower than traditional plastic products. The difference was mainly at the stages of plastic production and waste disposal, and the BPPs showed significant carbon reduction potential at the raw material acquisition stage. Waste disposal plays an important role in environmental impact, and composting and anaerobic digestion are considered to be preferable disposal methods for WBBPs. However, the high cost of biodegradable plastics is a challenge for their widespread use. This study has important reference significance for the sustainable development of the biodegradable plastics industry.

Scalable production of hydrophobic starch/beeswax films by continuous solution casting

AbstractStarch is an appealing natural polymer for the scaled‐up production of biodegradable plastics. However, the low water resistance of starch has made its broad applicability largely doubted. In this study, starch was combined with beeswax (BW) through a pilot scale continuous solution casting (CSC) technique to reduce water affinity while keeping the ensuing films totally biodegradable. The phase morphology, surface wettability, and water vapor permeability (WVP) of films were examined over a broad BW–starch mass ratio (0.3–0.7). Emulsified, surfactant‐free starch/BW films were successfully obtained at a productivity of 0.55 m2 film h−1. The water contact angle increased nearly by 100% at 30 wt% BW, leading to remarkable reductions in WVP. BW droplets well distributed within the starch matrix played a key role in enhancing the water barrier properties of films. CSC of starch/BW films offers a basis to design new hydrophobic formulations for applications that require biodegradable plastics with high moisture resistance.

Danimer Scientific and Chevron Phillips Chemical to collaborate to make biodegradable plastic products

Danimer Scientific and Chevron Phillips Chemical to collaborate to make biodegradable plastic products

Underutilized Malaysian Agro-Industrial Wastes as Sustainable Carbon Sources for Lactic Acid Production

Lactic acid is a versatile chemical with a wide range of industrial applications, including food additives as well as the production of biodegradable plastics, pharmaceuticals and cosmetics. LA can be produced through carbohydrate fermentation using various microorganisms, including lactic acid bacteria (LAB). However, the high production cost of commercial fermentation media for lactic acid raises concerns among researchers. Consequently, there is a demand for research to develop new, more affordable, and sustainable fermentation media. Utilizing underutilized agro-industrial wastes from Malaysia, particularly in the coconut, oil palm, rice, and sugarcane processing industries, offers several advantages. These include biomass reuse, cost-effective production of valuable chemicals, and agricultural waste reduction. This review discusses the potential of underutilized Malaysian agro-industrial waste from the coconut, oil palm, rice and sugarcane processing industries as sustainable carbon sources for LA production. The topics covered encompass the chemical and nutritional composition of the wastes, their potential for lactic acid fermentation with specific microorganisms, factors influencing lactic acid production, and potential applications. Additionally, this review also highlights the challenges and opportunities associated with reutilizing agricultural waste for lactic acid production.

New attempts on acidic anaerobic digestion of poly (butylene adipate-co-terephthalate) wastewater in upflow anaerobic sludge blanket reactor

Poly (butylene adipate-co-terephthalate) (PBAT) wastewater is a highly concentrated, acidic, and toxic wastewater generated from biodegradable plastics production. Large amounts of alkali would be consumed when treating PBAT wastewater by anaerobic digestion due to the low pH value. This study employed acidic anaerobic digestion to treat PBAT wastewater and compared to neutral anaerobic digestion. The results indicated that the COD removal rates in the acidic upflow anaerobic sludge blanket (UASB) reactor were 65.5% and 59.9%, respectively at influent pH 6.0 and 5.0 with the COD concentration of around 11,000 mg L−1, and the methane conversion efficiency were 172.5 and 183.8 mLCH4/gCODr (gCODr: COD removed amount), respectively. Correspondingly, the average COD removal and methane conversion efficiency in the neutral UASB reactor were 63.2% and 188.0 mLCH4/gCODr, respectively. The treatment efficiency of acidic and neutral UASB reactors for PBAT wastewater was similar. The hydrogenotrophic methanogenic activity was further enhanced in the acidic UASB reactor compared to the neutral one. The increase of alkalinity in the acidic UASB reactor (2.4 mmol L−1) was higher than the neutral (2.0 mmol L−1). A higher level of syntrophic acetate oxidation bacteria and hydrogenotrophic methanogen was enriched in the acidic UASB reactor, ensuring efficient treatment and saving costs.

Production of polyhydroxybutyrate from waste cooking oil using magnetically recoverable microbial-based nanocomposites as reusable inocula

Polyhydroxybutyrate (PHB) is produced during bacterial metabolism and can be used for the production of biodegradable plastics. The utilization of wastes as carbon sources and inoculum reuse are potential strategies to reduce production costs. In this study, a method for PHB production from waste cooking oil using a reusable inoculum was developed. Two microbial-based nanocomposites (fabricated bead and bacterial nanocomposites) were used as reusable inocula, and 6% waste cooking oil was used as a carbon source. The addition of 0.1% iron oxide (Fe3O4) increased PHB production and oil removal efficiency. Supplementation with 0.1% pumice enhanced the compressive strength and Young’s modulus of the fabricated bead nanocomposite containing a photosynthetic bacterium, alginate, Fe3O4, and pumice. The bead nanocomposite was reused for nine cycles with single harvesting of PHB. To improve the recycling time, free cells released from the bead nanocomposite were immobilized to generate a bacterial nanocomposite containing bacteria and Fe3O4. Bacterial nanocomposites showed the highest oil removal rates (38%–51%) and PHB contents in multiple harvests (19%–30%). The bacterial nanocomposite was recycled in 11 batches without deterioration and simplified using magnetic harvesting, which eliminated the incubation time and medium required for inoculum preparation. These results suggest that bead nanocomposites can be used to treat cooking oil until they disintegrate and release free cells that are immobilized with Fe3O4 to generate bacterial nanocomposites for unlimited recycling. This study introduces technology for PHB production from waste cooking oil.

Literature review on waste management of online food delivery industry in China

Meituan Waimai, which was officially launched in November 2013, has created a huge market for food delivery in China. After years of development, China’s online food delivery market reached RMB 664.62 billion in 2020. In 2022, Meituan Waimai and Ele.me, two food delivery platforms, have created a duopoly in China’s food delivery industry. Due to the success of the food delivery industry, a significant amount of food delivery packaging waste has caused far-reaching harm. This literature review primarily organizes the research on the impact of online food delivery packaging from the perspective of environmental protection. It uses the criterion layer index of online food delivery waste management ecosystem to analyze the impact of the government, environmental non-governmental organizations (NGOs), garbage recycling processors, consumers, online food delivery platforms, takeaway merchants, and takeaway packaging manufacturers. The review shows that scholars generally believe that takeaway waste management is a complex process involving multiple factors. The implementation of policies at the government level is inadequate, and studies at the environmental NGO level are scant. At the consumer level, more environmental awareness education is required. Online food delivery platforms and takeaway merchants should assume greater corporate social responsibility, and manufacturers of takeaway packaging need prioritize the substitution of environmentally friendly materials. There is a consensus that paper-made and recyclable packaging boxes are more environmentally friendly than degradable packaging, which is not as environmentally friendly as is commonly believed. The academia and the industry have conducted various studies and pilot projects on recyclable packaging. If all levels cooperate well, this will be an effective way to manage takeaway packaging garbage. At last, we propose the following assumptions for future research: Besides environmental hazards, takeaway garbage has caused direct or indirect physical harm to humans and animals. Increasing consumer awareness may increase their propensity to participate in governance. Additionally, existing food delivery platforms may need to improve their corporate social responsibility awareness to provide environmentally conscious consumers with sufficient and effective plastic reduction guidance measures during the ordering process. Moreover, will biodegradable plastic products face the same ironic situation as biofuels? That is, the initial intention of technology development is to improve the environment, but the actual process of production or processing may controversially aggravate the environment.

Aging behavior of biodegradable polylactic acid microplastics accelerated by UV/H2O2 processes

The usage of biodegradable plastics is expanding annually due to worldwide plastic limits, resulting in a substantial number of microplastics (MPs) particles formed from biodegradable plastic products entering the aquatic environment. Until now, the environmental behaviors of these plastic product-derived MPs (PPDMPs) have remained unclear. In this work, commercially available polylactic acid (PLA) straws and PLA food bags were used to evaluate the dynamic aging process and environmental behavior of PLA PPDMPs under UV/H2O2 conditions. By combining scanning electron microscopy, two-dimensional (2D) Fourier transform infrared correlation spectroscopy (COS) and X-ray photoelectron spectroscopy, it was determined that the aging process of the PLA PPDMPs was slower than that of pure MPs. The 2D-COS analysis revealed that the response orders for the functional groups on the PLA MPs differed during the aging process. The results demonstrated that the oxygen-containing functional groups of the PLA PPDMPs were the first to react. Subsequently, the –C–H and –C–C− structural responses began, and the polymer backbone was ruptured by the aging process. However, the aging of the pure-PLA MPs started with a brief oxidation process and then breakage of the polymer backbones, followed by continuous oxidation. Moreover, compared to the PLA PPDMPs, the pure-PLA MPs exhibited a greater adsorption capacity, which was increased by 88% after aging, whereas those of the two PPDMPs only increased by 64% and 56%, respectively. This work provides new insights into the behaviors of biodegradable PLA MPs in aquatic environments, which is critical for assessing the environmental risks and management policies for degradable MPs.