FTIR Analysis Research Articles

Microwave Properties of Composite Films Based on Polyvinyl Chloride and Brominated Activated Carbon

AbstractBrominated activated carbon (AC/Br2) powder was used as a filler in poly(vinyl chloride) (PVC) to prepare PVC‐based composite films by hot pressing. The AC/Br2 filler was obtained by liquid phase bromination and contained both oxygen and bromine. In comparison with the unmodified AC, the AC/Br2 was subjected to thermogravimetric analysis in air and argon and temperature‐programmed desorption mass spectrometry in vacuum, which identified carbon‐oxygen and bromine groups and showed the comparable thermal stability of AC/Br2 and AC. XPS shows the predominance of phenolic groups among the carbon‐oxygen groups. Scanning electron microscopy and transmission electron microscopy showed preserved morphology and microstructure, while N2 adsorption showed a microporosity decrease after bromination. FTIR analysis suggested non‐chemical interactions between PVC and AC/Br2. As the AC/Br2 content in the PVC‐based composite films increases from 0.2 to 30 wt %, the electromagnetic radiation (EMR) reflection at Ka‐band microwave frequencies increases. To reduce the EMR reflection, the proposed composite films should contain a maximum of 0.2 wt % AC/Br2. The results indicate that the microwave properties of PVC‐based composite films can be tuned by adjusting the AC/Br2 content.

Isolation, characterization and optimization of oleaginous Providencia vermicola as a feedstock for biodiesel production using Response Surface Methodology

Oleaginous organisms accrue more than twenty percent of their biomass as lipids and hence are promising feedstocks for biodiesel production. In this study, lipid accumulating bacteria were isolated from diesel-contaminated soils and screened with Sudan black B stain. The most oleaginous was done using 16s rRNA gene sequencing. Lipid production was initially optimized based on media, nitrogen source, pH and temperature. Response surface methodology (RSM) was then employed for the enhancement of lipid weight and content. Obtained lipid was converted to biodiesel using direct transesterification, and both lipid and biodiesel were characterized using FTIR. A total of thirteen bacteria were isolated and the most prominent lipid producer was identified as Providencia vermicola with lab number BA6. Preliminary optimization studies revealed optimum lipid production when nutrient broth and acetic acid served as carbon source; KNO3 as nitrogen source, pH 7.0 and 30 °C. Optimization using RSM resulted in a 5.1% and 74.1% increase in the biomass and lipid content of BA6 respectively. FTIR analyses confirmed the presence of functional groups characteristic of lipids and biodiesel. P. vermicola is a novel oleaginous organism that represents a promising feedstock for biodiesel production. HIGHLIGHTS The bacterium designated as BA6 identified as Providencia vermicola has the highest lipid contents of the oleaginous bacteria isolated. It accumulates lipids up to 47.73 % of its biomass The percentage lipids accumulation increased to about 74 % when RSM was used. Providencia vermicola is being reported as an oleaginous organism for the first time.

DEVELOPMENT OF MYCROCRYSTALLINE CELLULOSE ORIGINATE FROM SAGO (METROXYLON SAGU) STEM BARK BY HYDROLISIS METHODE USING NITRIC ACID

Objective: Microcrystalline cellulose (MCC) is an essential excipient in tablet formulation. Mostly MCC was obtained from wooden conifer stem fiber, therefore environment issues had been came up. Alternative sources for MCC which offer friendly conifer wood need to be explored. This study aimed to isolate and determine the characteristics of MCC originated from Sago (Metroxylon sago Rottb.) stem fibers as an promising alternative of MCC. Methods: MCC was prepared through pre-hydrolysis using an acetic acid solution, alkali heating using NaOH solution, and acid hydrolysis using nitric acid 0.3 N using three variations of heating temperature, namely 90, 95 and 100 °C. The characterization carried out were pharmaceutical grade, powder properties, FTIR analysis and powder morphology by SEM. Results: The yields obtained were 66.02; 65.53 and 65.08%, respectively. The characteristics of the MCC sample based on pharmaceutical grade quality were white to yellowish white powder, odorless, tasteless, insoluble in: ether, 96% alcohol, HCl 2N and NaOH 1N. The pH of the MCC suspension were 5.07-5.12, while moisture content were 3.67-4.17%, with loss on drying value as much as 0.37-0.4%, and ash content 1-2.17%. The value of permanganate number were 0.09-0.11, Hausner factor was between 1.05-1.25, and angle of repose were between 11.4-24.8°. Conclusion: Based on the results, it can be concluded that Sago is potent natural resource for MCC. The resulting MCC revealed physicochemical and characteristic of MCC, which almost similar to Avicel PH 102 as standard.

Growth of L asparagine monohydrate doped potassium dihydrogen phosphate semiorganic crystals and its structural, thermal and optical properties

A novel semiorganic crystal is harvested by doping organic amino acid L asparagine monohydrate (LAM) with inorganic compound Potassium dihydrogen phosphate (KDP) by adopting slow evaporation method. Rietveld refinement of the XRD data was performed and the structural study exhibits single phase nature of the LAM doped KDP (LAM-KDP) crystals with a slight decrease in c-axis of the unit cell parameters. Other crystallographic parameters such as crystallite size and strain were also evaluated. The interaction of LAM with KDP was studied from FT-IR analysis by detecting functional groups. The constituting elements of the crystal were identified by energy dispersive X-ray (EDX) analysis. Etching study has been employed to study surface morphology of these crystals. From UV–vis transmittance data, optical band gap and different optical constants like Urbach energy, dielectric constants, electrical and optical conductivities were evaluated. Optical transparency of the LAM-KDP crystals is observed to increase. The third order nonlinear susceptibility χ(3) and nonlinear refractive index n2 of the grown crystals have been predicted using empirical Miller's rule. The value of χ(3) has increased from 1.87 × 10−13 esu to 4.29 × 10−13 esu due to LAM doping. Change in enthalpy (ΔH), change in Gibb's free energy (ΔG) and activation energy Ea during chemical reaction were calculated by thermogravimetric analysis (TGA). Thermal decomposition characteristics of the crystals were analyzed by differential scanning calorimetry (DSC). The high transparency of LAM-KDP crystals in the entire visible spectrum and larger values of nonlinear susceptibility χ(3) and nonlinear refractive index n2 make the synthesized crystal applicable for NLO and optoelectronic devices applications.

Kinetic and Mechanism of Zerumbone Release from Cross-linked Gelatin-Zeolite Y Hybrid for Oral Anticancer Drug Delivery

A hybrid of zeolite Y-gelatin film as an oral dosage form for the natural anticancer drug was achieved by homogenously incorporating the drug-loaded zeolite Y into the gelatin solution. Drug ability was analyzed using computational and experimental approaches, drug encapsulation efficiency via the BET method, and possible interactions by FTIR analyses. Zerumbone released was done in both pH 1.2 and pH 7.4 mimicking the human gastrointestinal tract conditions for 24 hrs and subjected to kinetics study via suitable mathematical models to determine what governs the drug release with the results indicating that a sustained delivery of once-daily oral dosage form could be achieved.

Preparation, physicochemical analyses, and comparative evaluation studies of deep eutectic solvents (DES) from non-conventional precursor materials applied as catalytic curing agents for epoxy resin

Curing agents for epoxy resins play a significant role in initiating crosslinking reactions resulting in the hardened and durable material with enhanced properties as per end-user applications. The industrial world still lacks efficient, environmentally friendly, and cheap curing agents for epoxy resins. Here, we report the development of deep eutectic solvents (DESs) based on N, N’-Bis(2-aminoethyl)ethane-1,2-diamine (commonly known as triethylenetetramine, TETA) as hydrogen bond donor (HBD), and salicylic acid (SA) and choline chloride (CC) as hydrogen bond acceptor (HBA). The formulated DESs are suggested to be relatively safe, affordable, and eco-friendly and the active groups in the DESs are capable of initiating crosslinking reactions. The physical stability of the formulated deep eutectic solvents was examined by polarizing optical microscopic (POM) analysis, which confirmed the absence of any crystals or residues. The purity was ensured by 13C nmr spectroscopy. Additionally, supportive evidence for the hydrogen bond formation between the constituents was gained from the outcomes of FTIR, 1H nmr, and mass spectrometry. Deep depression in melting points was confirmed from DSC studies, and TGA suggested better thermal stability for DESs than its constituents. Density functional theory (DFT) at B3LYP6-31G* of Gaussian computational framework was applied to energetically optimize the isolated structure and determine the bond lengths in angstroms. The structural characteristics and nonbonding interactions of DESs were investigated by the same. In addition, the density and rheological characteristics were assessed for the ideal utilization of the formulated DESs as epoxy resin curing agents. The detailed comparative studies demonstrated the advantages of deep eutectic solvents over conventional curing agents. The efficacy of the formulations as a curing agent was primarily confirmed from FTIR analysis and the curing behavior was investigated by DSC studies.

Bioeconomic transformation of bio-oil production wastes: a novel adsorbent material for toxic dye adsorption and optimization of process parameters

In this study, for the first time, an adsorbent material was produced from the waste left behind after the bio-oil production process from Terebinth (Pistacia Terebinthus L.) seeds as part of bioconversion, and the adsorption of the hazardous dyestuff methylene blue from aquatic media was investigated. The characterization of the adsorbent was performed using FT-IR, SEM, and BET analysis. The characterization of methylene blue adsorption was conducted to fully understand its nature, including its kinetics, equilibrium, and thermodynamic works. The maximum adsorption capacity (q max) of the monolayer, as determined from the equilibrium data, was calculated to be 166.07 mg g−1. Additionally, the experimental design method was utilized to determine the optimum conditions of the methylene blue adsorption process under various conditions. This study revealed that activated carbons from Terebinth seeds can be used as an economical and environmentally friendly adsorbent, which is very suitable for the removal of highly toxic dyes.

Assessment of bioactive compound variations and in-vitro and in-vivo antioxidant activity in edible fresh and processed Bambusa nutans shoot through FTIR, GC/MS and HPLC analyses

This study explores the impact of processing techniques on the bioactive composition and antioxidant properties of Bambusa nutans shoots, an underutilized superfood. Boiling resulted in a significant reduction of total phenols (39.52%), flavonoid (8.07%), and tannin (27.77%). Conversely, fermentation increased total phenols (25.92%), tannin (34.72%), and phytosterol (75.39%). Antioxidant activities were notably higher in fermented-shoots, as indicated by DPPH and FRAP assays, and in-vivo experiments demonstrated increased GSH (31.85%) and decreased LPO levels (11.12%) post-administration of fermented-shoots extract. Spectral analysis revealed an increased diversity of compounds in fermented shoots, with GC/MS identifying hexadecane-1-ol in significantly higher proportions and 11 characteristic bands in FTIR spectra. HPLC analysis demonstrated changes in phenolic acids and flavonoid content, with fermentation enhancing 3,4,5-trihydroxybenzoic acid, 4′-hydroxycinnamic acid, benzene-1,2-diol, and luteolin contents. This study underscores the dynamic nature of B. nutans shoots, highlighting the potential for enhanced bioactivity and antioxidant properties through fermentation, offering promising avenues for culinary and pharmaceutical developments.

Sustainable and efficient oil-water separation using bio tin oxide-based superhydrophobic membrane

IntroductionSuperhydrophobic materials are considered an ideal method for oil-water separation. However, existing oil-water separation methods have the problem of manufacturing complex and toxic chemical reagents. To address the limitation, we proposed a novel approach to sustainable and efficient oil-water separation using a superhydrophobic membrane based on the Bio Tin oxide nanoparticles (Bio-SnO2 NPs).MethodsThe study involves synthesizing Bio-SnO2 NPs from the sunflower leaf extract which was natural and non-toxic and modifying textile fabric with a superhydrophobic coating (S.T.F.). Characterization techniques including SEM, FTIR, and BET analysis are employed to assess the structural and textural properties of the modified membrane.Results and DiscussionThe textile fabric was modified with a superhydrophobic coating (S.T.F.), demonstrating enhanced wettability, oil absorption capacity, and oil-water separation performance. The Bio-SnO2 NPs exhibited crystalline structures with a length of 90 nm and a diameter of 20 nm, as confirmed by SEM analysis. FTIR results revealed characteristic peaks at 3410 cm-1 and 642 cm-1, indicating the presence of hydroxyl group and Sn-O bonds confirming the successful synthesis of Bio-SnO2 NPs. BET analysis showed a substantial specific surface area of 413 m2/g and a pore volume of 0.19 cm3/g, emphasizing the textural properties. The FTIR and SEM techniques were used to study the characteristics of the textile fabric before and after modification with the superhydrophobic coat. The S.T.F. exhibited remarkable superhydrophobicity with a water contact angle of 152° and a water sliding angle of 4°. Absorption capacities for coconut oil, diesel, and hexane were found to be 70.4 g/g, 63.5 g/g, and 49.6 g/g, respectively, with excellent cyclic stability. Separation efficiency for hexane, diesel, and coconut oil was found to be 99.5, 97.1%, and 96.3%, respectively, with excellent cyclic stability. Mechanical stability test revealed superhydrophobicity retention even after an abrasion length of 200 mm. The chemical stability test indicated that the superhydrophobicity was maintained in the pH range of 3-11. Moreover, the flux for hexane, diesel, and coconut oil was 9400 L m−2 h−1, 8800 L m−2 h−1, and 8100 L m−2 h−1, respectively, highlighting the membrane’s efficient oil-water separation capabilities. These results collectively position the developed S.T.F. as a promising and sustainable solution for diverse oil-water separation applications.

Innovative Acrylic Resin-Hydrogel Double-Layer Coating: Achieving Dual-Anchoring, Enhanced Adhesion, and Superior Anti-Biofouling Properties for Marine Applications.

Traditional anti-corrosion and anti-fouling coatings struggle against the harsh marine environment. Our study tackled this by introducing a novel dual-layer hydrogel (A-H DL) coating system. This system combined a Cu2O-SiO2-acrylic resin primer for anchoring and controlled copper ion release with a dissipative double-network double-anchored hydrogel (DNDAH) boasting superior mechanical strength and anti-biofouling performance. An acrylamide monomer was copolymerized and cross-linked with a coupling agent to form the first irreversible network and first anchoring, providing the DNDAH coating with mechanical strength and structural stability. Alginate gel microspheres (AGMs) grafted with the same coupling agent formed the second reversible network and second anchoring, while coordinating with Cu2+ released from the primer to form a system buffering Cu2+ release, enabling long-term antibacterial protection and self-healing capabilities. FTIR, SEM, TEM, and elemental analyses confirmed the composition, morphology, and copper distribution within the A-H DL coating. A marine simulation experiment demonstrated exceptional stability and anti-fouling efficacy. This unique combination of features makes A-H DL a promising solution for diverse marine applications, from ship hulls to aquaculture equipment.

Enhanced simultaneous phosphate recovery and organics removal by a nucleation crystallization pelleting process

Naturally co-occurring phosphate (P) and dissolved organic matter (DOM) in raised livestock wastewater have caused increasing public concerns. This study fabricated a novel nucleation crystallization pelleting process (NCP) showing orientated P recovery and HA (as a major fraction of DOM) removal from wastewater. Results showed that after 120 h of continuous operation, the total removal efficiency of P and HA stabilized at 97.5 % and 92 %, respectively, by using a three-stage NCP process. The NCP results further demonstrated that the main recovery mechanism of P involves surface-induced precipitation of P in the form of hydroxyapatite (HAP) on the seed surface by modulating the supersaturation of HAP in the system. The FTIR, SEM-EDS, and XPS analysis combined with DFT calculations revealed the molecular-level mechanisms for removing HA, which were mainly controlled by Calcium ions bridging, H-bonding, and π-π stacking. More importantly, the attached HAP on the seed surface would enhance the mutual interaction with HA, further enhancing the removal efficiency of HA. This contribution not only opens a high potential avenue for further research on the simultaneous capture of P and organic matter but also sheds light on the development of the practical application of the NCP remediation strategies.

Heavy metal application of response surface optimized-lipopeptide biosurfactant produced by Pseudomonas aeruginosa strain CGA-02 in low-cost substrate

Cost-effective methods of biosurfactant production with minimal environmental impact are needed as global demand continues to increase. This study evaluated lipopeptide biosurfactant production in a Pseudomonas aeruginosa strain CGA-02 using a low-cost carbon substrate. The structural properties of the biosurfactant and applicability of the biosurfactant in heavy metal removal were evaluated. Response surface methodology (RSM) involving central composite design (CCD) was used to optimize process parameters to maximize biosurfactant production. The study identified sugar cane molasses and sodium nitrate as carbon and nitrogen sources of choice for bacterial growth and biosurfactant production, with a relatively 2.64-fold increase in biosurfactant yield under optimized conditions. Analysis of the biosurfactant measured a surface tension reduction of water from 72.2 ± 0.26 to 30.5 ± 0.2 mN/m at 40 mg/L critical micelle concentration. GC–MS and FTIR analysis revealed structural properties of the lipopeptide biosurfactant, with fatty acid components predominantly 9-octadecenoic acid (oleic acid), n-hexadecanoic acid, cyclotetrasiloxane and trimyristin, and infrared peaks belonging to amine, carboxyl, nitrile, alkanol, ether and carbonyl groups. Capture of heavy metals using the biosurfactant was evaluated in soil microcosms. Removal rates of 80.47, 100, 77.57, 100, and 97.57% were recorded for As, Pb, Hg, Cd and Cr respectively after 12 weeks of incubation. There was no significant difference (p < 0.05) in the removal efficiency of the biosurfactant and an analogous chemical surfactant, sodium dodecyl sulphate. First and second-order kinetic models described heavy metal removal rates by the biosurfactant. We demonstrate the production of a useful biosurfactant using low-cost waste carbon.

Synergistic effects of nucleating agent, chain extender and nanocrystalline cellulose on PLA and PHB blend films: Evaluation of morphological, mechanical and functional attributes

The current study focuses on reactive extrusion of poly (lactic acid) (PLA) and polyhydroxybutyrate (PHB) based blend films using epoxide styrene–acrylic (ESA) chain extender, pentaerythritol (PEOL) as a nucleating agent and cellulose nanocrystal (CNC). The blown films were subjected to various mechanical, thermal, barrier, and microstructural analyses to determine their suitability for packaging. Test results indicated that the incorporation of 0.5 wt% of chain extender significantly improved the elastic modulus and yield strength of PLA/PHB blend films. Further addition of 1 wt% of PEOL improved the crystallinity as well as mechanical strength in the films. FTIR analysis suggested chain conformations in different crystalline regions of PLA/PHB blend films whereas nucleation density and arrangement in crystal growth have been analysed by POM and SEM micro graphical studies. Additionally, the presence of CNCs within the PLA/PHB blend films showed an improved water vapour transmission rate (WVTR) of 90.53 g/m2.day revealing the creation of a tortuous path. Evaluation of optimum glossiness and haze of the films were done and the co-efficient of friction analysis depicted more anti-slip properties of the films.

Preparation of wheat straw-based aerogel and the research of it’s flame retardancy

Using waste biomass resources wheat straw(WS) as raw material, sodium alginate(SA) as basic skeleton and phytic acid(PA) solution as flame retardant, WS based composite aerogel(CA) was prepared in this research. Single factor experimental variables were used to optimize the preparation process conditions, and the relevant properties of CA were determined by FT-IR, limiting oxygen index, Raman test, etc. The experimental results show that the preparation conditions with better performance: the mass ratio of SA to WS was 1:1, the concentration of PA was 75%, the mass ratio of PA to SA was 1:4, and the mass ratio of PA to WS was 1:4. The obtained CAs have low density characteristics, the lowest density is 0.0122 g/cm3, the limiting oxygen index(LOI) attains a high level of 30.2%, while the vertical burning test(UL-94) demonstrates an impressive V-0 grade. FT-IR analysis showed that WS, SA and PA were physically cross-linked. The results of thermogravimetry analysis(TGA) showed that WS based CA had similar thermal degradation behavior，and raman analysis showed that the mixture of SA/WS/PA CA greatly improved the graphitization degree of the CA material, which helped to improve the stability of residual carbon ratio. WS produces no additional carbon dioxide throughout its life cycle, and the use of waste biomass WS in whole components does not need to be separated in advance, which is good for the environment, and reduces a lot of manpower, material and financial resources, and has more economic and application prospects. It is meaningful for the high-value utilization of waste resources, turning waste into treasure.

Adsorption of Diclofenac Sodium and Tetracycline From Aqueous Solution Using PVA Films Prepared with Modal/Cotton Fiber Wastes

AbstractIn this study, fiber‐polymer composite films were prepared by adding 0.5 g, 1.0 g, and 1.5 g of modal/cotton (50 : 50) waste to 10 % PVA film, and the properties of the films were revealed by SEM, FTIR analyzes and swelling percentage. It is observed that the strength of the bonds in the FTIR analysis decreases when modal/cotton fibers are added to the PVA film. While a 406 % swelling is achieved in the PVA film, the swelling percentages of the films decrease when modal/cotton fibers are added to the PVA film, and a greater swelling is observed at pH 9 compared to pH 5. The adsorption efficiency of tetracycline and diclofenac sodium on the films was researched at different pH levels and film doses. Tetracycline removal reached its highest value at pH 9, while diclofenac sodium removal reached its highest value at pH 5. Langmuir and Freundlich isotherm models were determined for tetracycline and diclofenac sodium adsorption. Tetracycline removal is better described by the Freundlich isotherm model, whereas diclofenac sodium removal fits the Langmuir isotherm model better. As a result, films prepared with modal/cotton waste not only provide tetracycline and diclofenac sodium removal but also contribute to waste recycling by utilizing waste fiber materials.

Efficient biodegradation of low-density polyethylene by Pseudomonas plecoglossicida SYp2123 was observed through FT-IR and FE-SEM analysis

Efficient biodegradation of low-density polyethylene by Pseudomonas plecoglossicida SYp2123 was observed through FT-IR and FE-SEM analysis

Synthesis and characterization of selenium-polyvinyl alcohol nanoparticles as eco-friendly corrosion inhibitor for carbon steel in 1.0 M H2SO4

Selenium nanoparticles capped with polyvinyl alcohol (Se-PVA NPs) have been synthesized by chemical reduction using ascorbic acid as a reducing agent. The synthesized nanoparticles were characterized using XRD, DLS, zeta potential, FT-IR, and TEM analysis and found to be stable. The solution of Se-PVA NPs was used as a carbon steel corrosion inhibitor in 1.0 M H2SO4. The effect of the presence of Se-PVA NPs in the corrosion medium was studied by potentiodynamic polarization and gravimetric analyses In the presence of Se-PVA NPs with a concentration of 600 ppm at 303 K, corrosion inhibition efficiency values of 92.86 % and 92.3 % were recorded by potentiodynamic polarization and gravimetric analysis methods, respectively. Over the Se-PVA NPs concentration range 100–600 ppm, it was found that increasing the concentration increases the inhibition efficiency, while the temperature has an adverse effect, inhibition efficiency values of 80.0 % was recorded at 323 K for the 600 ppm Se-PVA NPs solution. The potentiodynamic polarization measurements suggested that Se-PVA NPs work as a mixed-type inhibitor. The corrosion inhibition process was confirmed by testing the used specimens’ metal surface using SEM and AFM techniques, which showed that the acidic medium’s negative impact (distortion and roughness) on the carbon steel surface was reduced significantly in the presence of Se-PVA NPs. The inhibitor’s adsorption on the metal surface was studied. It obeys the Langmuir isotherm with a mixed-type adsorption process. The related kinetic and thermodynamic parameters were investigated.

Synthesis and in silico inhibitory action studies of azo-anchored imidazo[4,5-b]indole scaffolds against the COVID-19 main protease (Mpro)

The present work elicits a novel approach to combating COVID-19 by synthesizing a series of azo-anchored 3,4-dihydroimidazo[4,5-b]indole derivatives. The envisaged methodology involves the l-proline-catalyzed condensation of para-amino-functionalized azo benzene, indoline-2,3-dione, and ammonium acetate precursors with pertinent aryl aldehyde derivatives under ultrasonic conditions. The structures of synthesized compounds were corroborated through FT-IR, 1H NMR, 13C NMR, and mass analysis data. Molecular docking studies assessed the inhibitory potential of these compounds against the main protease (Mpro) of SARS-CoV-2. Remarkably, in silico investigations revealed significant inhibitory action surpassing standard drugs such as Remdesivir, Paxlovid, Molnupiravir, Chloroquine, Hydroxychloroquine (HCQ), and (N3), an irreversible Michael acceptor inhibitor. Furthermore, the highly active compound was also screened for cytotoxicity activity against HEK-293 cells and exhibited minimal toxicity across a range of concentrations, affirming its favorable safety profile and potential suitability. The pharmacokinetic properties (ADME) of the synthesized compounds have also been deliberated. This study paves the way for in vitro and in vivo testing of these scaffolds in the ongoing battle against SARS-CoV-2.

Efficacy and Functional Mechanisms of a Two-Stage Pretreatment Approach Based on Alkali and Ionic Liquid for Bioconversion of Waste Medium-Density Fiberboard.

A novel pretreatment strategy utilizing a combination of NaOH and 1-Butyl-3-methylimidazolium chloride ([Bmim]Cl) was proposed to enhance the enzymatic hydrolysis of abandoned Medium-density fiberboard (MDF). The synergistic effect of NaOH and [Bmim]Cl pretreatment significantly improved the glucose yield, reaching 445.8 mg/g within 72 h, which was 5.04 times higher than that of the untreated samples. The working mechanism was elucidated according to chemical composition, as well as FTIR, 13C NMR, XRD, and SEM analyses. The combined effects of NaOH and [Bmim]Cl led to lignin degradation, hemicellulose removal, the destruction and erosion of crystalline regions, pores, and an irregular microscopic morphology. In addition, by comparing the enzymatic hydrolysis sugar yield and elemental nitrogen content of untreated MDF samples, eucalyptus, and hot mill fibers (HMF), it was demonstrated that the presence of adhesives and additives in waste MDF significantly influences its hydrolysis process. The sugar yield of untreated MDF samples (88.5 mg/g) was compared with those subjected to hydrothermal pretreatment (183.2 mg/g), Ionic liquid (IL) pretreatment (406.1 mg/g), and microwave-assisted ionic liquid pretreatment (MWI) (281.3 mg/g). A long water bath pretreatment can reduce the effect of adhesives and additives on the enzymatic hydrolysis of waste MDF. The sugar yield produced by the combined pretreatment proposed in this study and the removal ability of adhesives and additives highlight the great potential of our pretreatment technology in the recycling of waste fiberboard.

A synthesis of styrene-grafted starch accompanied with reaction condition optimization and microstructural and macroscopic property analysis

Styrene grafting is efficient to alter starch macroscopic property. Nevertheless, reaction mechanism, condition and products structure and properties are blurry. A deep exploration is necessary. Herein, K2S2O8 and styrene were chosen for corn starch modification. Reaction conditions involving K2S2O8 and styrene amounts, temperature and period were explored. Concurrently, microstructural and macroscopic properties of modified starches were explored via FT-IR, XPS, 13C NMR, GPC, XRD, SEM, TGA, DSC, CA and water dispersibility analysis. Main results reveal that K2S2O8 and styrene amounts, temperature and period as 3 and 200 wt%, 50 °C and 3 h is an optimized condition for starch grafting styrene, achieving a grafting yield (GY) as 45.8 wt%. GPC, XPS and 13C NMR analysis certified successful grafting and grafting mainly occurred at C-3 site OH within glucose unit. This variation converted starch crystalline shape transformation from A-typed to V-typed accompanied with crystallinity, thermal-stability and swelling characteristic decrease and surface hydrophobicity elevation. With GY increased from 0 to 45.8 wt% crystallinity decreased from 38.7 to 15.1%, thermal-decomposition temperature decreased by 10 °C, gelatinization temperature and CA increased by 50 °C and 70°, respectively. It seems a small amount styrene grafting can alter starch macroscopic property such as hydrophilicity efficiently, readily to manufacture hydrophobic starch. This hydrophobic starch might have a potential use in plastic industry, enlarging starch use application, meaningful.