Degree Of Biodegradation Research Articles

Disintegration and marine biodegradability of biocomposite using Pennisetum setaceum fiber and PLA as matrix

The accumulation of plastics in the environment is a well-recognized issue. To address this, biodegradable materials such polylactic acid (PLA) have been developed. In natural environments such as soil or water, PLA degradation progresses slowly but steadily. To accelerate the degradation of the material, this study investigates the degradation of a biocomposite material using PLA as a matrix and Pennisetum setaceum fiber as reinforcement. Disintegration and marine biodegradability tests, both at the seawater/sediment interface and in marine sediment, were conducted. Different measurement tests were employed to quantify the degradation of PLA and composite samples, focusing on the mass loss and the variation of the mechanical and thermal properties. The results consistently demonstrated greater mass loss and mechanical property deterioration during the disintegration test compared to the marine biodegradability tests. Notably, the composite material exhibits more significant degradation than the pure polymer without fiber. For composite, the addition of fiber increased the degree of biodegradability compared to the plastic matrix.

Circular Economy in Action: Transforming Textile Waste into sustainable soil additives - physicochemical properties and biodegradability

In recent years, there has been an increasing interest in soil additives used in environmental ecosystems. Currently, most soil amendments are produced from synthetic materials. Some synthetic amendments break down into microplastics, which persist in the environment and can be ingested by soil organisms, affecting soil health and biodiversity and the chemicals they contain can leach into groundwater. At the same time, the number and availability of biodegradable technologies are limited, and the aspects related to their biodegradation in soil are not sufficiently known. The study developed a sustainable water-saving and vegetation-supporting technology in the form of a biodegradable water-absorbing geocomposite (BioWAG). BioWAGs were produced using biodegradable materials derived from animal and plant waste, such as waste wool, jute, and linen. In a three-year field experiment, their physicochemical properties in the soil were analyzed. These were characterized using a.o. surface weight, scanning electron microscopy (SEM), and FTIR. The results indicate that the degree of biodegradation of materials used in BioWAG depended on the raw material and production technology. Needle-punched nonwovens underwent intensive biodegradation just 6 months after being buried in the soil, while stitched nonwovens retained their mechanical properties even for three growing seasons. In the case of seamed non-woven fabrics, a decrease in selected physical parameters was observed. The addition of wool-based soil additive, a decrease in surface mass was observed by 85% after 6 months, 88% after 18 months and 90% after 30 months. Regardless of the waste materials used, BioWAGs provided plants with continuous access to water and nutrients. The work indicates a sustainable method of managing textile waste and analyzes its properties in the soil, which enables the development of technologies based on natural fibers for applications such as geotextiles, mulches and controlled-release fertilizers. The technology was developed in line with the principles of a circular economy and can improve soil quality, mitigate the effects of climate change and reduce environmental pollution.

Mixed dimensional assembly of biodegradable and antifouling wood-based covalent organic framework composite membranes for rapid and efficient dye/salt separation

Manipulating materials of different dimensions into heterogeneous nanofiltration membranes with unique physicochemical properties and molecular sieving channels provides an effective way for accurate and fast molecular separation. Here we introduce a heterogeneous structure hybrid connection strategy to fabricate biodegradable wood-based covalent organic framework (COF) composite membranes. As a proof of concept, 3D Picea jezoensis (Siebold & Zucc.) Carrière was selected as the substrate of the membrane and in situ growth of 2D iCOF selective layers. Effective modulation of iCOF layers by 1D sulfonated polyaryletherketone (SPEEK-Na) using the “needle and thread” method. The rearrangement of the above multidimensional materials formed charge-regulated properties of laminar nano-channels and smooth hydrophilic contact area, thereby endowing specific molecular transport pathways and sieving capability for efficient dye/salt separation under ultra-low pressure of 0.5 bar. The wood-based heterostructured membranes exhibited high dye rejection (>97 %), low salt rejection (<10 %), and high permeance (172.34 L m−2 h−1 bar−1), which is superior to many reported dye/salt separation membrane materials. In addition, the system exhibited a certain degree of operational stability, good antifouling, and soil biodegradability. Overall, this work enables the design and fabrication of heterostructured separation membranes to be obtained from nature and used in nature, resulting in efficient and sustainable water purification applications.

APPLICATION OF BENZOCARBAZOLE MOLECULAR MIGRATION MARKERS IN RECONSTRUCTING RESERVOIR FILLING AT THE SOLVEIG FIELD, NORWEGIAN NORTH SEA

Benzocarbazole (BC) migration tracers were used to investigate the complex filling of reservoir segments at the Solveig field in the Norwegian North Sea. The study suggests that the benzocarbazole ratio [a]/([a]+[c]) of crude oils and extracts decreases with inferred increasing migration distance. The complex filling history of the Solveig field is evident from the observation of variable degrees of palaeo biodegradation associated with two palaeo oil‐water contacts in residual oil zones below non‐ to moderately biodegraded live oil columns. Live oil properties also vary significantly across the field. Benzocarbazole ratios (BCRs) obtained from oils and reservoir core extracts appear not to be affected by biodegradation and indicate a migration and filling trend from NW to SE. The BCR values were set by the initial phase of filling and do not show any overprint effects as a result of later and more mature oil charges.BCRs from both oils and extracts of reservoir cores, particularly those composed of clean sands, helped to reconstruct migration processes in the Solveig field. Migration is construed to have first filled reservoir segment D in the NW of the field and to have continued further east towards segment C, and then via segment B and finally into segment A. Migration then continued along the southern margin of the Haugaland High to a well location to the east of the Solveig field. A fractionation effect for benzocarbazoles derived from oils versus those from extracts was noted and was attributed to differential partitioning behavior. Nevertheless, spatial trends for oil‐ and extract‐derived BCRs were congruent. This allowed the generation of spatially more highly‐resolved benzocarbazole datasets for migration assessment by combining data from both samples types (oil and reservoir extracts) if partitioning is accounted for.

An Assessment of Biodegradability and Phytotoxicity of Natural Rubber in a Simulated Soil Condition via CO2 Evolution Measurement.

In this study, the biodegradation of various natural rubber (NR) samples, i.e., neat NR and NR filled with two different curative contents was investigated under a long-term simulated soil condition at a temperature of 25 ± 2 °C in accordance with ISO 17556. Natural clay loam soil, with a pH of 7.2 and a water holding capacity of 57.6%, was employed. Under controlled test condition both unvulcanized and vulcanized NR samples having low curative content, respectively designated as UNRL and VNRL, exhibited similar biodegradation behaviors to the neat NR. They showed fast biodegradation at the early stage, and their biodegradation rate did not significantly change throughout the test period (365 days). However, for the NR samples having high curative content, respectively called UNRH and VNRH for the unvulcanized and vulcanized samples, a biodegradation delay was observed within the first 130 days. Surprisingly, the UNRH showed a relatively high biodegradation rate after the induction period. At the end of the test, most of the rubber samples (the neat NR, UNRL, VNRL, and UNRH) showed a comparable degree of biodegradation, with a value ranging from 54-59%. The VNRH, on the other hand, showed the lowest degree of biodegradation (ca. 28%). The results indicate that the number of curatives does not significantly affect the biodegradability of unvulcanized NR in the long term, despite the fact that a high curative content might retard microorganism activity at the beginning of the biodegradation process. Apparently, crosslink density is one of the key factors governing the biodegradability of NR. The phytotoxicity of the soils after the biodegradation test was also assessed and represented in terms of seedling emergence, survival rate, and plant biomass for Sorghum bicolor. The values of seedling emergence (≥80%), survival rate (100%), and plant biomass of all soil samples were not statistically different from those of the blank soil, indicating the low phytotoxicity of the tested soils subjected to the biodegradation of the rubber samples. Taken as a whole, it can be concluded that the CO2 measurement technique is one of the most effective methods to assess the biodegradability of rubbers. The knowledge obtained from this study can also be applied to formulate more environmentally friendly rubber products.

Maleated epoxidized natural rubber grafted cassava starch/silver composite coating for cloth glove: Preparation and physical properties

The green composite was obtained from maleated epoxidized natural rubber (MENR) latex grafted cassava starch (CS) (MNS) and silver nanoparticles (AgNPs) by using a green route process. The immersion of AgNPs in the MNS matrix was checked with UV–visible spectrometer. The SEM was applied to study the morphology of AgNPs particle. The thermal stability of the MNSAg composite increased with increasing AgNPs. The AgNPs well distributed in the MNS matrix. The silver was used to facilitate the facile and fast preparation and to improve the mechanical strength and thermal stability at 420–450 °C of the MNSAg composites. The MNSAg composite containing AgNPs exhibited excellent antibacterial activities against both Escherichia coli and Staphylococcus aureus. Moreover, it showed the high UV absorption. It was used to coat with cloth gloves. The degree of biodegradation of this sample was about 80–90 % after being buried in soil.

A comprehensive review on natural macromolecular biopolymers for biomedical applications: Recent advancements, current challenges, and future outlooks

Versatile material properties coupled with high degree of biocompatibility and biodegradability has made biopolymers as potential candidates for diverse applications in the biomedical field. Natural biopolymers derived from various plant, animal and microbial sources with different biochemical compositions are extensively used in biomaterial industry with or without further medication to their native form. Biopolymeric biomaterials have been employed in a wide range of biomedical applications like tissue engineering, drug delivery, bone regeneration, wound dressings and cardiovascular surgery. Carbohydrate based biopolymers and protein based biopolymers are extensively used for several applications in the biomedical field including cartilage regeneration, periodontal tissue regeneration, bone regeneration, corneal regeneration, drug delivery and wound healing. This review work presents a comprehensive outlook on the applications of various biopolymers in biomedical field. The work elaborates the biochemistry of these polymers with special focus on their crucial properties in the biomedical industry. Further a detailed description on the most recent application of various biopolymers in the biomedical filed is presented in this review. This work further summarizes the current challenges and future prospects in the use of biopolymers in biomedical field.

Бактерии-деструкторы с ростстимулирующими свойствами для использования в экологической

A topical research trend in ecological biotechnology is the search and study of microorganisms-destructor resistant to additional pollutants and growth-stimulating to remediant-plants. Four strains of hydrocarbon-oxidizing microorganisms isolated from soil samples were identified on the basis of cultural-morphological, physiological-biochemical properties and a comparative analysis of the gene encoding 16S rRNA. The bacteria Acinetobacter calcoaceticus UOM 22 and UOM 29, A. courvalinii UOM 35 showed a significant degree of oil biodegradation in a liquid medium at 24 and 8 °C (93.0–95.6% and 78.4–81.1%, respectively). In the same conditions these indicators were 44.8 and 33.7%, respectively for strain Rhodococcus erythropolis UOM 33. All microorganisms grew in the presence of aromatic hydrocarbons (including polycyclic hydrocarbons), were resistant to NaCl (5–7%) and lead ions (1.00–1.25 g/L). They were capable of nitrogen fixation and inorganic phosphate dissolution, indole-3-acetic acid synthesis (150–1416 ng/ml of culture liquid) and hydrolytic enzyme lipase production. We found that A. calcoaceticus UOM 22 and A. courvalinii UOM 35 strains increased the barley seeds germination by 8.6 and 10.5%, as well as A. calcoaceticus UOM 29 and A. courvalinii UOM 35 stimulated the barley root growth by 16.3 and 18.1% respectively. The results of the experiments indicate the possibility of using A. calcoaceticus UOM 22 and UOM 29, and A. courvalinii UOM 35 strains for cleaning oil-contaminated soils, including in combination with remediant-plants.

Methodology for assessing the degree of biodegradability of plastics based on lignocellulose-containing raw materials without resins

Methodology for assessing the degree of biodegradability of plastics based on lignocellulose-containing raw materials without resins

Alternative end-of-life options for disposable bioplastic products: Degradation and ecotoxicity assessment in compost and soil

Four different end-of-life options for disposable bioplastic cups were investigated and compared based on their environmental implications. Two products with distinct polymeric composition were tested simulating the following scenarios at laboratory scale: i) industrial composting (180 days at 58 °C); ii) anaerobic digestion followed by industrial composting (45 days at 55 °C and 180 days at 58 °C); iii) anaerobic digestion followed by direct digestate use on soil for agricultural purposes (45 days at 55 °C and 180 days at 25 °C); iv) uncontrolled release into a soil environment (180 days at 25 °C). Ecotoxicity tests were run at the end of each experiment to investigate the effects of the materials on three main groups of terrestrial model organisms: plants, earthworms and nitrifying bacteria. Complete biodegradation of the cups was observed in 180 days in the scenarios involving composting environment. A low degree of biodegradation (22.9 ± 4.5%) of the digestates in soil was observed, warning for a potential micro-bioplastics discharge into the environment. No degradation was observed for the cups in soil during the same testing period. Ecotoxicity tests revealed a negative effect on plants biomass growth across all samples, which was 17–30% lower compared to the blank sample. The experimental campaign highlighted the need for a systematic assessment of controlled treatment of bioplastics, as well as the need for a harmonized legislative framework.

A new method to quantify the source contribution of mixed biodegraded oil based on pareto-optimized nonnegative matrix factorization and chord diagram visualization

The biogenic information of different components in crude oils with varying degrees of biodegradation is partially obscured, making traditional molecular indicators ineffective in determining the contributions of mixed sources. Previous studies have mainly focused on calculating mixed source proportion for normal oils, with few investigations involving biodegraded mixed oils. Developing a quantitative method for the mixed source contribution of biodegraded oils using machine learning (ML) algorithms is a significant attempt both to the exploration practice and theoretical progress. Taking the biomarker parameters resistant to biodegradation of 150 oil samples as input datasets, a new method called Pareto-Optimized NMF (PONMF) was proposed in this study, which combines multi-objective optimization (Pareto optimization) with non-negative matrix factorization (NMF) to analyze the relationship between biodegraded oils in the absence of source rock samples or original end-member (EM) oils while satisfying non-negativity constraints and additional constraint conditions. This method decomposes the matrix of crude oil samples into multiple end-members, each representing a possible input from a hydrocarbon source rock. Analysis of the end-member characteristics facilitates the deduction of potential hydrocarbon source layers and the traits of their depositional environments. This examination is supported by data derived from 15 prospective hydrocarbon source rock samples, which were employed to ascertain the actual geological significance of the end-members. The chord diagram depicts the visualization results of the overall relative contribution of source rock end members to crude oil in each area after the PONMF calculation results. The relative contribution of source rocks in different areas to the investigated crude oil samples is proportionate, and the arc length can reflect the contribution of the three sets of source rocks to a certain area. The findings indicate that the oils extracted from the stratified reservoirs in Eastern Chepaizi are primarily derived from the Permian source strata within the Shawan Depression, with a significant contribution ranging from 30% to 90% (EM2), and a lesser extent from the Carboniferous sources, contributing between 5% and 30% (EM1). Conversely, the provenance of oil in Western Chepaizi is overwhelmingly attributed to the Jurassic source interval located in the Sikeshu Depression, where EM3 accounts for over 85% of the source. Meanwhile, the oils in the Central Zone exhibit a composite origin, intermingling contributions from both EM1 and EM3. The advantage of this method is that it does not require direct access to hydrocarbon source rock samples or end-member oils but infers potential hydrocarbon source layers through the existing mixed-source oil samples. The PONMF method provides an effective tool for identifying the sources of biodegraded oils and can be used to study potential hydrocarbon source rock analysis for oils that have undergone biodegradation after hydrocarbon accumulation.

Non-invasive measurement of spoilage of packed fish using halochromic sensor

Purpose This study aims to develop a pH-functional thin-film sensor for non-invasive measurement of spoilage of packed fish. Design/methodology/approach At first, polymers of natural origin such as hydroxy(propyl)methyl cellulose, potato dextrose agar and starch alongside a pH sensitive-mixed indicator formulation were used to produce thin film sensor. The developed thin film sensor was tested for monitoring the spoilage of seafood stored at 4°C. Using ultraviolet-visible and Fourier-transform infrared spectroscopy, the halochromic sensor was characterised. In addition, the halochromic response of the thin film was directly correlated to the total volatile base nitrogen emitted by the packaged fish, pH, microbial activity and sensory evaluation. Findings The results suggested the developed biopolymer-based thin film sensor showed different colours in line with the spoilage of the packed fish, which could be well correlated with the total volatile base nitrogen, microbial activity and sensory evaluation. In addition, the thin film sensors exhibited a high degree of biodegradability. The biopolymers-based thin film halochromic sensor has exhibited excellent biodegradability along with sensitiveness towards the spoilage of the packed fish. Originality/value In the future, consumers and retailers may prefer seafood containers equipped with such halochromic sensors to determine the degree of food deterioration as a direct indicator of food quality.

Gelatin methacrylate/poly(2-ethyl-2-oxazoline) porous hydrogel loaded with kartogenin drug as a biocompatible scaffold for cartilage tissue regeneration

Gelatin methacrylate (GelMA) is a biocompatible, and biodegradable macromolecule developed from a natural polymer, gelatin, via covalent bonding with methacrylic groups. In this research, GelMA/poly(2-ethyl-2-oxazoline) (PEtOx) hydrogel loaded with Kartogenin (KGN) drug was developed with the aim to regenerate the extracellular matrix of cartilage. The morphology, swelling ratio, degree of hydrophilicity, biodegradability, elastic modulus, blood compatibility, drug release and cytotoxicity were assessed. The hydrogel was found to be hydrophilic, highly porous and biodegradable, with 92 % porosity and ∼ 43 % weight loss within 14 days. Mechanical testing revealed that the elastic modulus of GelMA (20 wt%)/PEtOx (45 wt%) was close to that of cartilage. Good blood compatibility and sustained drug release in the damaged cartilage tissue environment were also detected. According to flow cytometry and MTT tests, due to the presence of KGN, up to 75 % of the cells can survive and easily adhere to the developed scaffold. The results confirm the ability of GelMA/PEtOx hydrogel containing KGN to increase cell adhesion by preserving cell population combined with minimal cytotoxicity, which may be advantageous for use in cartilage regeneration following in-vivo implantation.

Applications of Cellulose‐Based Nanomaterials for Sustainability and Therapeutics: A Review

AbstractCellulose is a natural fibrous carbohydrate, is the main structural element of plant cell walls, and is the most abundant natural polymer found in the biosphere. Due to its abundance and chemical stability, it has been used as a raw material in various industries for thousands of years. Due to developments in nanotechnology, materials that are used in macroscale abundantly are also utilized for nanomaterial design, and cellulose‐based nanomaterials have gained more interest in recent years. The unique properties of cellulose‐based nanomaterials including their chemical stability, high degree of crystallinity, biocompatibility, biodegradability, and tunability of their chemical (e.g., surface modification) and physical (e.g., shape) properties make them good candidates for functional nanomaterial design. This review brings advances in cellulose‐based nanomaterials for application in two major fields, sustainability and therapeutics.

Biodegradation of polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics by floc-forming bacteria, Bacillus cereus strain SHBF2, isolated from a commercial aquafarm.

The ubiquitous proximity of the commonly used microplastic (MP) particles particularly polyethylene (PE), polypropylene (PP), and polystyrene (PS) poses a serious threat to the environment and human health globally. Biological treatment as an environment-friendly approach to counter MP pollution has recent interest when the bio-agent has beneficial functions in their ecosystem. This study aimed to utilize beneficial floc-forming bacteria Bacillus cereus SHBF2 isolated from an aquaculture farm in reducing the MP particles (PE, PP, and PS) from their environment. The bacteria were inoculated for 60 days in a medium containing MP particle as a sole carbon source. On different days of incubation (DOI), the bacterial growth analysis was monitored and the MP particles were harvested to examine their weight loss, surface changes, and alterations in chemical properties. After 60 DOI, the highest weight loss was recorded for PE, 6.87 ± 0.92%, which was further evaluated to daily reduction rate (k), 0.00118 day-1, and half-life (t1/2), 605.08 ± 138.52 days. The OD value (1.74 ± 0.008 Abs.) indicated the higher efficiency of bacteria for PP utilization, and so for the colony formation per define volume (1.04 × 1011 CFU/mL). Biofilm formation, erosions, cracks, and fragments were evident during the observation of the tested MPs using the scanning electron microscope (SEM). The formation of carbonyl and alcohol group due to the oxidation and hydrolysis by SHBF2 strain were confirmed using the Fourier transform infrared spectroscopic (FTIR) analysis. Additionally, the alterations of pH and CO2 evolution from each of the MP type ensures the bacterial activity and mineralization of the MP particles. The findings of this study have confirmed and indicated a higher degree of biodegradation for all of the selected MP particles. B. cereus SHBF2, the floc-forming bacteria used in aquaculture, has demonstrated a great potential for use as an efficient MP-degrading bacterium in the biofloc farming system in the near future to guarantee a sustainable green aquaculture production.

Optimized Synthesis of Poly(Lactic Acid) Nanoparticles for the Encapsulation of Flutamide.

Biopolymeric nanoparticles (NPs) have gained significant attention in several areas as an alternative to synthetic polymeric NPs due to growing environmental and immunological concerns. Among the most promising biopolymers is poly(lactic acid) (PLA), with a reported high degree of biocompatibility and biodegradability. In this work, PLA NPs were synthesized according to a controlled gelation process using a combination of single-emulsion and nanoprecipitation methods. This study evaluated the influence of several experimental parameters for accurate control of the PLA NPs' size distribution and aggregation. Tip sonication (as the stirring method), a PLA concentration of 10 mg/mL, a PVA concentration of 2.5 mg/mL, and low-molecular-weight PLA (Mw = 5000) were established as the best experimental conditions to obtain monodisperse PLA NPs. After gelification process optimization, flutamide (FLU) was used as a model drug to evaluate the encapsulation capability of the PLA NPs. The results showed an encapsulation efficiency of 44% for this cytostatic compound. Furthermore, preliminary cell viability tests showed that the FLU@PLA NPs allowed cell viabilities above 90% up to a concentration of 20 mg/L. The comprehensive findings showcase that the PLA NPs fabricated using this straightforward gelification method hold promise for encapsulating cytostatic compounds, offering a novel avenue for precise drug delivery in cancer therapy.

Physicochemical characterization of university campus’ wastewater for internal treatment system installation (Casablanca, Morocco)

Today, protecting water resources and their sustainable use has become an obligation of people and organizations. Wastewater management and reclamation are the most important solutions to protect these resources. This study aims to determine the wastewater physicochemical quality of the Faculty of Sciences Ben M'Sick (FSBM) (Casablanca, Morocco) to establish the appropriate system for their treatment and internal reclamation. The results show that averages of FSBM's wastewater temperature vary between 17.64 and 19.55 °C, 7.18 and 8.18 for pH, and 2.47 and 3.98 mS.cm-1 for electrical conductivity.. The COD, BOD5, and TSS average values oscillate respectively between 967.44-1,151.08 mg.L-1, 70.5-119.05 mg.L-1, and 223.64-1,659.74 mg.L-1, and those of total phosphorus between 2 and 3.99 mg.L-1. The determination of the biodegradability degree of the discharge, through the calculation of COD/BOD5, BOD5/COD, TSS/BOD5, COD/TP, COD/NH4+ ratios, and oxidizable matters (OM,) reveals that the FSBM's wastewater has a heterogeneous character with a high load of oxidizable matter difficult to biodegrade. Despite its low biodegradability, the FSBM’s wastewater could be treated using a biological treatment system, preceded by a physicochemical treatment to eliminate non-biodegradable chemical substances. Such a choice of wastewater treatment system requires prior experimental investigations and laboratory tests.

Geochemical Characteristic and Source Correlation of Biodegraded Oils from the Western Halaalate Area of Junggar Basin

The relationship between biodegraded oil and its source has long been a complex and contentious topic. The Western Halaalate area is located in the Piedmont area on the northwest margin of the Junggar Basin. Source rocks of the Fengcheng Formation exist both locally and in the nearby Mahu Depression. In order to determine the source of biodegraded crude oil in this area, the molecular marker characteristics of biodegraded crude oil were analyzed by gas chromatography-mass spectrometry. The results showed that the vitrinite reflectance (Ro) of source rocks of the Permian Fengcheng Formation in the nearby Mahu Depression is greater than 1.3% and has entered a high mature stage of condensate oil and moisture gas; the source rock of Permian Fengcheng Formation in Western Halaalate area is in a mature stage with Ro of 0.79%~1.13%. The ascending configuration of tricyclic terpenes C20-C21-C23 for the crude oil samples found in the Carboniferous strata of the Western Halaalate Area is consistent with the characteristics of the Fengcheng Formation source rocks, which are present in both the Western Halaalate Area and the nearby Mahu Depression. Chromatography spectrometry examination shows that crude oils have undergone a varying degree of biodegradation. The Carboniferous oil was originated from the in situ Fengcheng Formation source rocks based on the application of molecular markers resistant to biodegradation, such as maturity parameters, salinity parameters, the new gammacerane index, and aromatic hydrocarbon parameters, combined with the analysis of hydrocarbon migration pathway. In addition, the oil biodegradation alteration rules in the Western Halaalate area were clarified, which advances regional knowledge of the relationship between biodegraded oil and source rocks.

Source and geological significance of Jurassic asphalt in the Ruoqiang Sag of Southeast Depression, Tarim Basin, Northwestern China

The Southeast Depression of the Tarim Basin has a very low petroleum exploration degree, and currently, no industrial oil and gas have been discovered. Many hydrocarbon shows exist in the Ruoqiang Sag, where hydrocarbon sources and accumulation processes are unclear. Only two potential Jurassic hydrocarbon source rocks developed in the Ruoqiang Sag, the Yangye (J2y) lacustrine mudstone of the Middle Jurassic and the Kangsu (J1k) coal-bearing mudstone of the Lower Jurassic. In this study, the Jurassic asphalt found in the QD1 well, combined with the source rocks of drilling cores and outcrops, was used to explore the possible hydrocarbon source and forming process in the Ruoqiang Sag using oil-source correlation and hydrocarbon accumulation geochronology methods. The asphalts have lower light and heavy rare earth fractionation than the J2y mudstone, and the total rare earth element (ΣREE) content, chondrite-normalized curves, and δEu and Y/Ho values are similar to those of the J1k mudstone, especially for the J1k coal. The n-alkane ratios of the carbon preference index and the odd-to-even preference (OEP) of Jurassic asphalts are greater than 1.0, indicating that its source rock has experienced low thermal evolution. All Jurassic samples have similar source-related biomarkers but different maturity-related parameters, and the thermal evolution degree of asphalt is close to the J1k mudstone and coal but slightly higher than the J2y mudstone. Meanwhile, rhenium–osmium isotopes show the asphalts are formed in 192+30/−45 Ma, which is similar to the J1k sedimentation time. The asphalts contain coal macerals and probably derived from the asphaltene precipitated by the J1k coal during the early coalification. The low abundance of 25-norbornanes with a non- or slight petroleum biodegradation degree indicates the asphalt was generated relatively late and migrated into the J2y formation along the faults, possibly accompanied by the striking activities of the Altyn Tagh Fault during the Neotectonics movement. This study provides evidence for the J1k coal-bearing strata serving as the effective source rock in the Ruoqiang Sag and increases confidence for Jurassic petroleum exploration in the Southeast Depression of the Tarim Basin. The structural and lithological traps near hydrocarbon source stoves, where Jurassic strata were deeply buried and far from the Altyn Tagh Range, are favorable oil and gas exploration targets.

Effective prevention of structure II gas hydrate formation using the newly synthesized kinetic inhibitors

Gas hydrate deposition is a complex issue with significant implications for the oil and gas industry. The formation of solid gas hydrates in the hydrocarbon transportation pipelines leads to production disruptions and potentially even complete blockages, resulting in huge financial losses and operational difficulties. For over two decades, kinetic gas hydrate inhibitors have played a crucial role in preventing the formation of gas hydrates within the flow lines of oil and gas production. They directly influence the kinetics of hydrate formation, hindering nucleation and slowing down crystal growth. In this study, five new waterborne polyurethanes (WPUs) with varying degrees of hydrophobicity as inhibitors for cubic structure II gas hydrates were synthesized and tested using rocking cells and differential scanning calorimetry. The synthesis of WPUs involved the reaction between dialkylamines (diethyl, dipropyl, dibutyl, dibenzyl, and dioctyl) and glycidol under mild conditions. All WPUs effectively prevented gas hydrate formation, and a correlation between their efficiency and the alkyl chain length was observed. The inhibitory efficacy of WPUs increased with the extension of the alkyl chain from ethyl to butyl. WPU-DBuA, featuring butyl groups, exhibited the highest inhibition activity. It provided a subcooling temperature of 12.9 and 15.6 °C at 0.25 and 0.5 wt%, respectively, surpassing commercial samples, such as Luvicap EG and Luvicap 55 W. Additionally, the solutions containing 1 and 2 wt% of WPU-DBu exhibited maximum subcooling temperatures of 16.2 °C and 16.7 °C, respectively, which correspond to a 79.7 % and 85.4 % reduction in gas uptake during hydrate growth compared to pure water. However, the inhibitory power of WPUs diminished with larger alkyl (dioctyl) or aromatic groups (dibenzyl), indicating that dibutyl represents the optimal alkyl length for achieving maximum performance. Moreover, WPUs demonstrated a reduction in hydrate conversion under static conditions, signifying their efficiency when the flow is stopped. WPUs lowered the onset temperature of hydrate formation from 3 °C in pure water to temperatures below −12 °C. Thus, WPUs demonstrated a remarkable ability to prevent the formation of structure II gas hydrates, even under high subcooling conditions. Additionally, WPU-DBuA exhibits a considerable degree of biodegradability, as evidenced by its biodegradation level of 44 %, suggesting that it has the potential to break down more easily in the environment compared to Luvicap 55 W. This research contributes to a deeper understanding of the structure–property relationships of KHIs. This can facilitate the development of more effective and eco-friendly inhibitors, which helps address environmental concerns associated with using KHIs in the oil and gas industry.