Changes In Functional Groups Research Articles

Water Hyacinth Plant Fibre Characterization

This work is on the specie of the water hyacinth (WH) in the Northern part of Nigeria taken from the lake in Jalingo in the Sahel region of the country. The basic characteristics of the fibres are studied for use in concrete and other allied construction works. They are subjected to physical and chemical tests for the determination of their properties. X-ray diffraction and scanning electron microscopy are applied to study the crystalline phases and mineral oxides, and the morphology and structural characteristics of the WHFs. The TGA/DTA and FTIR methods of analysis are applied to the WHFs to identify and investigate the thermal stability and percentage of weight loss on temperature, and the SEM for the morphology and structural characteristics of the WH fibre. The results show that the presence of peaks on the spectra of the cellulose samples corresponds to bands of microcrystalline cellulose. The WH plant fibre has a moisture content of approximately 13.7 %, density of 666.7 kg/m3, specific gravity of 0.86, and water absorption of 1067 %, and the cellulose, hemicellulose, lignin are 14.1, 21.5, 7.1 %, respectively. The WH fibre has a tensile strength of 0.12 MPa, Young Modulus of 7.7 GPa, elongation of 4.8 %, tensile extension at break of 2.89 mm, and energy at break of 1.04 x 10-3 J. The XRD diffractogram characterization shows that the WH fibre is crystalline in nature, while the FT-IR shows the functional group change of each treatment respectively. The thermal decomposition process of the WH fibre resulted in similar TG and DTG curves due to being lignin cellulosic material. These curves showed a distinct DTG peak (cellulose) and a high-temperature tail (lignin). The morphology of WH fibre shows a well-shaped fibril with a rigid lignin structure coated surface with the capacity to hold the liquid contents with good absorbency. The chemical compound compositions of the WH fibre contains Ca, K, Cl, C, Al, Si, Fe, S, Y, Ti, P, Mg, Na, and N.

Algal deterioration of PET (polyethylene terephthalate) plastic bottle in combination with physical and chemical pretreatments: A macrocosm study

Plastic pollution has become an environmental issue worldwide because of its slow degradation and persistent nature. Many traditional methods exist and are practiced here to handle and reuse plastic waste, but those need to be more capable of tackling increasing waste volume. Biological plastic waste management could be a sustainable way to ensure environmental quality. Therefore, this study aimed to screen the bio-deterioration of PET wastes using physical and chemical pretreatments. We kept PET samples in freshwater and marine water media designed to support algal growth and incubated those under direct or indirect sunlight or in dark conditions. We observed algal growth and measured deterioration of PET samples using the tensile strength test, FTIR, and viewed surface properties using FESEM. Acid pretreatment and exposure to direct sunlight left the PET most fragile. FTIR analysis also supported the observation, and changes in functional groups are evident. Heat pretreatment usually reduces the volume and thus increases strength. Bottles incubated under direct or indirect sunlight supported the algal growth. The most prevalent algal species found in freshwater environments include Volvox, Chlorella vulgaris, Craticula cuspidate, Navicula pupula, Synedra ulna, and marine environments include Palisada perforate, Ulva flexuosa, Cladoptera herpestica, and Blindingia minima. Algal growth increases the porosity and surface cracks of PET bottles. Though FTIR analysis did not show any change in functional groups, except for acid pretreatment, upon algal growth, the transmittance increase indicated decay of PET samples.

Antimicrobial and Antibiofilm Potential of PEGylated Chitosan-Based Nano-Antibiotics Against Multidrug-Resistant E Coli Strains

Antimicrobial and Antibiofilm Potential of PEGylated Chitosan-Based Nano-Antibiotics Against Multidrug-Resistant E Coli Strains

Study on the inhibitory effect of inhibitor based on the coal molecular structure analysis: A case study of Zhundong coal, Xinjiang, China

The aim of this work is to use the changes in coal molecular structure to study the effect and mechanism of inhibitors, and to provide a reference for better preventing and controlling coal spontaneous combustion. In this study, Xinjiang Zhundong coal was used to construct the macromolecular structure. The changes in the molecular structure of the coal under different inhibitor concentrations and temperature conditions were analyzed by Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis. ChemDraw and Materials Studio were used to construct a coal molecular structure model with an inhibitor concentration of 20 % at 50 ℃. Results showed that the molecular formula of the ZD2–1 is C222H123O39N. The coal molecule contained a higher number of aliphatic hydrocarbon branches and a lower degree of aromatic ring condensation. When heated to 300 ℃, the proportion of adsorbed oxygen in raw coal decreased obviously, while the reduction of adsorbed oxygen was inhibited under inhibitor conditions. The change of functional groups of coal samples was obvious under 20 % inhibitor concentration, and the dosage was less than that of 30 % inhibitor concentration, revealing the optimal inhibitory effect on coal samples of Zhundong with this concentration.

Effect of AES anionic surfactant on the microstructure and wettability of coal

The paper object is high-quality Shenmu bituminous coal modified by fatty alcohol polyoxyethylene ether sodium sulfate (AES) surfactant. The changes in functional groups, free radicals, Zeta potential, and contact angle of coal modified in AES anionic surfactant were analyzed. Based on the molecular structure of Shenmu coal, a coal-AES-water three-phase dynamic model was constructed. The wetting mechanism of coal was studied by molecular dynamics. The research has demonstrated that as the mass fraction of AES surfactant increases, the proportion of polar groups (-OH, C–O–C, –COOH, –CO), free radical content and Zeta potential increased significantly. The size of contact angle displayed a major negative linear correlation with the proportion of polar groups and free radicals, but positively linearly correlated with the Zeta potential. In the coal-AES-water three-phase dynamic model, the AES molecules adhere to coal molecules as hydrophobic group, while hydrophilic groups extended into the water. This increased H2O diffusion coefficient, enhanced action energy between coal and water interface, decreasing surface tension and achieving effective wetting of the coal. This paper supplies s a new idea for selecting efficient surfactants to change the coal microstructure. It is of major importance for improving coal wettability and offers a theoretical foundation for gas drainage and disaster prevention.

Structural, chemical and technofunctional properties pectin modification by green and novel intermediate frequency ultrasound procedure

The impact of intermediate frequency ultrasound (IFUS, 582, 864 and 1144 kHz), mode of operation (continue and pulsed) and ascorbic acid (Aa) addition on the structural, chemical and technofunctional properties of commercial citrus high methoxyl-grade pectin (HMP) was investigated. The chemical dosimetry of IFUS, monitored by the triiodide formation rate (I3−), demonstrated that the pulsed ratio (1900 ms on/100 ms off) at the three frequencies was similar to that of continue mode but IFUS1144 kHz produced more acoustic streaming demonstrated by the height liquid measured using image analysis. In presence of Aa, HMP presented higher fragmentation than in its absence. IFUS did not give rise any changes in the main functional groups of the HMP. In general, a reduction in molecular weight was observed, being the presence of Aa the most influencing factor. Regarding monosaccharides, IFUS modified the structure of homogalacturonan and rhamnogalacturonan-I and increased of GalA contents of the HMP in presence of Aa at the above three frequencies. A reducing of the consistency index (k) and increasing of the flow index (n) of HMP were showed by IFUS frequency and Aa addition. The emulsifying activity and stability index were increased for HMP treated by IFUS in continue mode at all frequencies and in presence of Aa. The results presented in this research shown the effectiveness of IFUS as tool to modify pectin into different structures with different functionalities.

An investigation on the structural stability of ZIF-8 in water versus water-derived oxidative species in aqueous environment

The zeolitic-imidazolate-framework-8 (ZIF-8) is one of the extensively studied metal-organic frameworks (MOF) materials because of its unique structure. For its potential applicability in numerous fields, it becomes crucial to have detailed studies on the structural stability of ZIF-8, especially in aqueous environments. A number of studies have been conducted to investigate the breakdown process of the ZIF-8 structure in water; which is known as the hydrolysis of ZIF-8. However, those studies reported different opposing experimental observations on the role of water on the structural stability of ZIF-8, which created obscurity in understanding this phenomenon. This study explored the effects of different water-derived species on the structural stability of ZIF-8; specifically, examined the effects of only water and water with different oxidative species that may be generated by water molecules' dissociation under external energy or catalyst presence. To this effort, we experimentally probed the physical and chemical structural changes of ZIF-8 in DI water and three different solutions of hydrogen peroxides (H2O2); taking H2O2 as the source of oxidative species. To assess the changes in elemental compositions, chemical bonds, functional groups, crystal structure, and morphology, all the samples were analyzed by X-ray photoelectron spectroscopy (XPS), energy-dispersive x-ray (EDX) spectroscopy, Fourier Transform Infrared (FTIR) spectroscope, X-ray diffractometer (XRD), and scanning electron microscope (SEM). Significant structural changes in ZIF-8 occurred mainly in the presence of oxidative species in water. Notably, oxidative species’ concentration exceeding 1 M heightened the deformation of the ZIF-8 structure.

Insight into the effect of osmosis agents on macro- and micro- texture, water distribution, and thermal stability of instant controlled pressure drop drying peach chips

To investigate the influence of sugar structure on the quality of peach chips produced using osmotic dehydration (OD) in combination with instant controlled pressure drop (DIC) drying, erythritol, glucose, maltose, and trehalose were selected as osmotic agents. The properties of the osmotic solutions, as well as the macro- and micro-texture, water distribution, and thermal stability of peach chips were investigated. Results showed that OD pretreatments inhibited the formation of large cavity structures. The highest hardness (101.34 N) and the lowest hydrophobicity (0°) were obtained in erythritol-OD samples. Trehalose-OD samples with the most homogeneous pore structure exhibited the highest crispness (1.05 mm) and the highest glass transition temperature (52.06 °C). Various absorption peaks of peach chips pretreated with different OD methods, characterized by Raman spectroscopy, suggested changes in composition and functional groups due to the diffusion of sugars into the cells of peach tissues, which also contributed to the higher Tg.

Molecular insights into the bonding mechanisms between selenium and dissolved organic matter

Natural organic matter (NOM) plays a critical role in the mobilization and bioavailability of metals and metalloids in the aquatic environment. Selenium (Se), an environmental contaminant of aquatic systems, has drawn increasing attention over the years. While Se is a vital micronutrient to human beings, animals and plants, excess Se intake may pose serious long-term risks. However, the interaction between Se and dissolved organic matter (DOM) remains relatively unexplored, especially the reaction mechanisms and interactions of specific NOM components of certain molecular weight and the corresponding functional group change. Herein, we report an investigation on the interactions between Se and DOM by focusing on the mass distribution profile change of operationally defined molecular weight fractions of humic acid (HA) and fulvic acid (FA). The results showed that across all molecular weights studied, HA fractions were more prone to enhanced aggregation upon introduction of Se into the system. For FA, the presence of Se species results in aggregation, dissociation, and redox reactions with the first two being the major mechanisms. Total organic carbon analysis (TOC), UV–vis spectroscopy (UV–vis), and Orbitrap MS data showed that [10, 30] kDa MW fraction had the largest aromatic decrease (CRAM-like, lignin-like and tannin-like) upon addition of SeO2 via dissociation as the dominant mechanism. Fourier transform infrared spectroscopy (FT-IR) revealed that Se based bridging or chelation of functional groups from individual DOM components through hydrogen bonding in the form of SeO⋯H and possibly Se⋯H and/or attractive electrostatic interactions lead to aggregated DOM1⋯Se⋯DOM2. It was concluded from two-dimensional correlation analyses of excitation emission matrix (EEM) and FT-IR that the preferred Se-binding follows lipid ➔ peptide ➔ tannin ➔ aromatic functionalities. These results provide new understanding of Se interactions with various NOM components in aquatic environments and provide insight for Se assessing health risk and/or treatment of Se contaminated water.

Metal–Organic Framework‐Assisted Rational Design of Multicolor Solid‐State Fluorescent Carbon Nanodots and Its Application for LEDs

AbstractCarbon nanodots (CDs) are a new type of carbon‐based fluorescent nanomaterials, but they are limited in many applications due to the inherent fluorescence weakening and quenching problems suffered in solid state. Herein, ZIF‐8, a class of metal–organic framework (MOF) is employed as a matrix to immobilize fluorescent CDs, resulting in the strong luminescence of CDs achieved in solid state. The as‐synthesized CDs@ZIF‐8 fluorescent powders possess blue, green, and red emissions with the main emission at ≈495, 528, and 600 nm, and the corresponding photoluminescence quantum yields (PLQYs) are as high as 25.89%, 52.24%, and 15.42%, respectively. It is found that the encapsulation of ZIF‐8 with CDs will increase the excitation dependence of the product fluorescence, which may be attributed to the carrier effect of ZIF‐8 as a carrier of CDs and some surface defects or surface functional groups change of the CDs introduced by ZIF‐8. In addition, the encapsulation of CDs with ZIF‐8 may result in the charge transfer. Importantly, the prepared CDs@ZIF‐8 phosphors present a promising application in the fabrication of monochromatic light‐emitting diodes (LEDs). The synthesis design is expected to provide technical support for future solid‐state fluorescent CDs preparation and applications.

Adjustable strength and toughness of dual cross-linked nanocellulose films via spherical cellulose as soft-phase

Nanocellulose films possess numerous merits ascribing to their inherent biocompatibility, non-toxic and biodegradability properties. The potential for practical applications would be improved if their mechanical strength and toughness requirements could be met simultaneously. Herein, dual cross-linked nanocellulose (DC) film was fabricated by the treatments of chemical and physical cross-linking, which was mechanically superior to pure nanocellulose (CNF) films. To further increase the toughness of DC films, spherical cellulose (Sph) was incorporated into DC film (DC-Sph film), and analyzed under different humidity conditions (RH) (from 10 % to 90 %). The changes of functional groups of CNF, DC and DC-Sph films were detected by FTIR and XPS spectrum. The epichlorohydrin and Sph content were optimized, followed by the investigation of RH on the toughness of films. The highest tensile strength (146.6 ± 4.6 MPa) was obtained in DC film at 50 % RH, while the DC-Sph film showed the largest toughness (40.3 ± 3.7 kJ/m2) at 70 % RH. Furthermore, the possible toughening mechanism of DC-Sph film was also discussed.

Novel rejuvenators for sustainable recycling of aged SBS modified bitumen: Performance evaluation and reactive mechanism analysis

The performance of aged styrene-butadiene-styrene (SBS) modified bitumen (SMB) is jointly dominated by the aging of bitumen and degradation of SBS crosslinking network structure. Despite some epoxy reactive rejuvenators which can re-crosslink SBS fragments are able to reconstruct the SBS cross-linking network compared with conventional rejuvenator, the performance of aged SMB regenerated by existing epoxy reactive reactants is unbalanced achieving good low temperature performance by sacrificing high temperature performance. In order to further improve the comprehensive road performance of regenerated SMB, a novel reactive rejuvenator was proposed and assessed in this study aiming at effectively improving the high temperature performance of regenerated SMB. The restoration effectiveness of the reactive rejuvenators was evaluated and compared by the physical properties, rheological properties and FTIR of rejuvenated SMB. The physical and rheological experimental results show that 2,2'-[1,3-phenylenebis (oxymethylene)] dioxirane (RDGE) and 1,6-hexanediol diglycidyl ether (HDDGE) are beneficial to high and low temperature performance of regenerated SMB, respectively, and their composite action can complement each other. Compared with N, N-dimthylbenzylamine (BDMA), 3,6,9,12-tetraazatetradecane-1,14-diamine (PEHA) with crosslinking effect can excellently make up for the disadvantages of epoxy rejuvenator, which has better and balanced recovery effect in consideration of both low and high temperature properties of regenerated SMB. The reactive rejuvenator containing PEHA and RDGE can further alleviate high temperature performance loss of regenerated SMB by an appropriate mix ratio. The changes of chemical functional groups of FTIR and fluorescence microscope directly prove that a novel recovery reaction for degraded SBS network structure via the introduction of PEHA (a kind of polybasic primary amines) is conducive to balancing high and low temperature performance of regenerated SMB.

K2CO3‐loaded γ‐Al2O3 for acid removal in waste transformer oil

AbstractTransformer oil plays a critical role in ensuring the insulation and normal operation of power transformers. However, during operation, the transformer oil would undergo oxidation and degradation, leading to the formation of acids and polar compounds that increase its acidity and degrade its performance. Hence, the recycling and regeneration of aged transformer oil is an essential practice in transformer maintenance, contributing significantly to the extension of a transformer's operational lifespan and the reduction of potential risks. Adsorption separation is a preferred method for regeneration, offering simplicity and high efficiency. This study focuses on impregnated γ‐Al2O3 as an adsorbent for acidity removal in waste transformer oil. We conducted static adsorption experiments to investigate the optimal loading amount of the active component and the best calcination temperature for acid removal. XRD technique is employed to monitor the phase changes of the carrier during the calcination process. BET analysis is used to observe variations in the specific surface area and pore volume of the adsorbent during the modification process. DTG‐TGA is utilized to assess the weight loss during the calcination process. FTIR is employed to observe changes in functional groups during modification and adsorption processes. Along with these investigations, a study is also carried out to assess the dynamic acid removal performance of the acid‐removing adsorbent loaded into a fixed bed. The findings contribute to the development of sustainable methods for regenerating transformer oil, ensuring efficient and environmentally friendly operations.

Improving the Physical Properties of Starch-Based Powders for Potential Anti-Adhesion Applications.

Postoperative adhesion is one of the most common complications that occur during and after surgery; thus, materials that can prevent adhesion are often applied. Starch powders with a high water absorption capacity are preferred, and many studies have focused on increasing the water absorption of modified starches, as native starch powders display poor water-holding capacities. The effects of salts on the physical properties of acetylated distarch phosphate potato starch powders were investigated here. Changes in functional groups, the crystal structures of modified starch, particle morphologies, water absorption, viscosity, and in vivo adhesion were investigated. The results showed that salts greatly improved the water absorption and viscosity of acetylated distarch phosphate potato starch powders. Among the three different salt-modified starch powders, NaCl-modified starch powders displayed higher water absorption and viscosity and demonstrated better in vivo anti-adhesion performance. The results of this study propose a potential biomaterial that may function as an anti-adhesive, potentially leading to reduced surgical risks and a better quality of life for patients.

One-electron oxidant-induced transformation of dissolved organic matter: Optical and antioxidation properties and molecules

Dissolved organic matter (DOM) is a major sink of radicals in advanced oxidation processes (AOPs) and the radical-induced DOM transformation influences the subsequent water treatment processes or receiving waters. In this study, we quantified and compared DOM transformation by tracking the changes of dissolved organic carbon (DOC), UVA254, and electron donating capacity (EDC) as functions of four one-electron oxidants (SO4•−, Cl2•−, Br2•−, and CO3•−) exposures as well as the changes of functional groups and molecule distribution. SO4•− had the highest DOC reduction while Cl2•− had the highest EDC reduction, which could be due to their preferential reaction pathways of decarboxylation and converting phenols to quinones, respectively. Br2•− and CO3•− induced less changes in DOC, UVA254, and EDC than SO4•− and Cl2•−. Additionally, DOM enriched with high aromatic contents tended to have higher DOC, UVA254, and EDC reductions. Decreases in hydroxyl and carboxyl groups and increases in carbonyl groups were observed in these four types of radicals treated DOM using Fourier transform infrared spectroscopy. High resolution mass spectrometry using FTICR-MS showed that one-electron oxidants preferred to attack unsaturated carbon skeletons and transformed into molecules featuring high saturation and low aromaticity. Moreover, SO4•− was inclined to decrease oxidation state of carbon and O/C of DOM due to its strong decarboxylation capacity. This study highlights the distinct DOM transformation by four one-electron oxidants and provides comprehensive insights into the reactions of one-electron oxidants with DOM.

Dielectric analysis of surface modified nano-graphite: effects of frequency and thickness

The nano-graphite (NG) and acid modified nano-graphite (ANG) have been synthesized from graphite powder via mixture of strong acid (sulphuric acid and nitric acid) respectively by a soft chemistry route involving microwave, ultrasonic method and characterized by high-resolution electron microscopy (HR-TEM), scanning electron microscopy (SEM), fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), clearly demonstrated the successful synthesis of acid modified NG. SEM images confirmed the surface morphology of NG, and ANG and HR-TEM study shows the nanoparticles size of NG and ANG. FTIR data confirmed the presence of acid functional groups on the surface of synthesized NG powder. XRD data of NG and ANG shows that 2θ is at 26.43° and 0.336 nm is an interlayer distance (d). NG and ANG pellets have been prepared for their dielectric analysis with frequency for different thickness. The dielectric loss tangent (tanδ) spectra show relaxation peak with frequency and peak shifts due to presence of polar groups in the ANG. The capacitance values of NG and ANG decrease with frequency and increase with thicknesses due to the capacitive nature of nanoparticles. The dielectric permittivity decreases with frequency and increases with thickness due to the charge orientation and dipole moment change of functional groups of synthesized NG, and ANG. The electrical conductivity of NG and ANG nanoparticles increases with frequency and thickness of NG and ANG pellets due to the conductive nature. Electrical conductivity and dielectric permittivity of NG and ANG are found to highly rely on thickness, according to the dielectric evaluation.

Acidity’s Impact on Yield, Morphological Structure, and Surface Functionalities of Polyaniline Synthesised via Oxidative Polymerisation

This research aimed to examine how varying the acidity levels during the chemical oxidative polymerisation (COP) of aniline affects the colour, yield, morphology, and surface functionalities of polyaniline (PANI). In the COP method, aniline monomer was first dissolved in hydrochloric acid (HCl) medium; the solution was then drop added with ammonium persulfate to initiate the polymerisation process. To answer the research objective, the medium acidity was manipulated using different concentrations of HCl (i.e., 0 M, 0.01 M, 0.1 M, 1 M and 10 M). The as-synthesised PANIs were then purified and characterised for their physicochemical properties. The findings revealed that reducing the medium pH from 2.35 (in distilled water) to 0.80 (in 10 M HCl) resulted in a colour change from light brownish to dark green, indicating the formation of emeraldine PANI. Furthermore, it was observed that the amount of PANI yield is inversely related to the medium pH. A decrease in medium pH from 2.35 to 0.80 remarkably increased the PANI yield by 3.2 times. Regarding morphological structure, higher medium acidity produced PANI with well-defined globule shapes, while lower HCl concentrations resulted in a mixed morphology including globules, tubes, and plate-like structures. In addition, it was found that the diameter of globule-like PANI has increased from ~266.67 nm to ~508.33 nm, when the HCl concentration was changed from 0 M to 10 M. Apparently, increasing the acidity of the COP medium promotes enlargement of the PANI size. Despite that, there is not much change in the surface functional groups of the formed PANI. Overall, this study offers insights into manipulating PANI properties by adjusting the medium acidity during the COP process. While the impacts of medium acidity on yield, morphology, and functionalities of PANI were revealed, further investigation is required to evaluate the effect on electrical properties.

Performance of HNO3-Activated Water Hyacinth-Eichhornia crassipes Bioadsorbent in Adsorbing Lead Metal Ions (Pb2+) in Battery Industry Wastewater Discharge

Elemental lead is one of the pollutants generated from batteries. To overcome this problem, technologies such as the use of bioadsorbents have been developed to reduce heavy metal content in wastewater. This study aims to determine the adsorption of lead metal ions (Pb2+) through the use of a water hyacinth (Eichhornia crassipe) bioadsorbent activated with nitric acid (HNO3). Another objective is to obtain the optimum adsorption time on battery industry waste discharges. Post-treatment characterization using FT-IR. Contact time variations (20, 30, 40, 50, 60, 70, 140, 210, and 280 minutes) were used to carry out the lead metal adsorption process on a standard solution of metal ions (Pb2+), 20 ppm. The results showed that the optimum contact time was 210 minutes. This achievement was used as the contact time for reducing the levels of Pb2+ metal ions. The quantity of the remaining Pb2+ metal ion content was 0.4184 ppm. Indirectly, the bioadsorbent performance was 94.8655%. Characterization through FT-IR equipment before activation of water hyacinth bioadsorbent gave results of O-H, C-H, C=O, and C-HO functional groups. These findings indicated the presence of lignin, hemicellulose, and cellulose compounds in the sample before activation. Then, the involvement of 1 N HNO3 solution (as an activator) resulted in a decrease in the quantity of C=O and C-OH functional groups. The process of applying the solution was able to break a number of chains between lignin and hemicellulose. After the adsorption process was given, the waste left the vibrations of O-H, C-H, and ≡C-H groups at wave numbers shifted in a smaller direction. This can occur due to changes in functional groups that have bound metal ions first.

Exploring genetic landscape of low-density polyethylene degradation for sustainable troubleshooting of plastic pollution at landfills

Plastic pollution increases globally due to the high volume of its production and inadequate mismanagement, leading to dumps in landfills affecting terrestrial and aquatic ecosystems. Landfills, as sink for plastics, leach various toxic chemicals and microplastics into the environment. We scrutinized the genetic expression for low-density polyethylene (LDPE) degradation via microorganisms to investigate cell viability and metabolic activities for biodegradation and genetic profiling. Samples were collected from the Pirana waste landfill at Ahmedabad, Gujarat, which is one of the largest and oldest municipal solid waste (MSW) dump sites in Asia. Results analyzed that isolated bacterial culture PN(A)1 (Bacillus cereus) is metabolically active on LDPE as carbon source during starvation conditions when incubated for up to 60 days, which was confirmed via 2,3,5-triphenyl-tetrazolium chloride (TTC) reduction test, reported cell viability and LDPE degradation. Abrasions, surface erosions, and cavity formations were analyzed via scanning electron microscopy (SEM), whereas the breakdown of high molecular polymers converted to low molecules, i.e., depolymerization, was also observed via Fourier-transform infrared (FTIR) spectroscopy over 90 days, along with changes in functional groups of carboxylic acids and aldehyde as well as the formation of polysulfide, aliphatic compounds, aromatic ethers, alcohols, and ether linkages. Further, transcriptomic analysis was performed via DESeq2 analysis to understand key gene expression patterns and pathways involved in LDPE degradation. During the initial phase of LDPE degradation, genes related to biological processes, like membrane transportation, ABC transporters, carbon and lipid metabolism, fatty acid degradation/oxidation, and TCA cycle, are likely to indicate pathways for stress response and molecular functions, like oxidoreductase, catalytic, lyase, transferase, and hydrolase activities were expressed. Interlinking between metabolic pathways indicates biodegradation process that mineralizes LDPE during subsequent incubation days. These pathways can be targeted for increasing the efficiency of LDPE degradation using microbes in future studies. Thus, considering microbial-mediated biodegradation as practical, eco-friendly, and low-cost alternatives, healthy biomes can degrade polymers in natural environments explored by understanding the genetic and enzymatic expression, connecting their role in the process to the likely metabolic pathways involved, thereby increasing the rate of their biodegradation.

Enhancing flame retardant and wrinkle-resistant performances of silk fabric with bio-based Maillard reaction products between glucose and poly(glutamic acid)

Bio-based materials have garnered considerable attention in the flame retardant field due to their inherent safety and environmental benefits. This study introduces a novel and eco-friendly flame retardant prepared through the Maillard reaction between glucose and poly(glutamic acid) for treating silk fabric. The study elucidates the synthesis of Maillard reaction products (MRPs) and verifies their deposition onto the silk fabric surface by observing changes in surface morphology, functional groups, and charged characteristics. The flammability tests demonstrate that MRPs treated silk fabrics had a high limiting oxygen index of over 27 % and a charred length of less than 12 cm, indicating effective flame retardancy. Moreover, the introduction of MRPs led to a significant decrease in smoke release when silk fabric underwent combustion. This observation can be attributed to the enhanced char formation and increased thermal degradation temperature of MRPs treated silk fabric. The electrostatic interaction between silk fiber and MRPs contributed to the fabric's resistance to repeated washing. Moreover, MRPs treated silk fabric retained their tensile properties and showed enhanced wrinkle-resistant performance. Generally, this research opens up a new path for the green preparation of halogen-free and phosphorus-free flame retardant protein fibers.