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This study investigates the efficacy of a prepared Ni/θ-Al2O3 catalyst during the pyrolytic conversion of Parachlorella kessleri HY-6 and compares the results with non-catalytic conversion. The catalyst was characterized by techniques such as Brunauer–Emmett–Teller (BET) for surface area, acidity, and X-ray powder diffraction (XRD). Isoconversional and combined kinetic methods were used to study the pyrolytic kinetics of the process. Ni/θ-Al2O3 was used at 10, 20, and 30% of the algal biomass. The addition of Ni/θ-Al2O3 facilitated the conversion by lowering the mean activation energy during pyrolysis. The catalytic effect was more pronounced at lower and higher conversions. The presence of the catalyst facilitated the pyrolysis as indicated by the lower value of activation energy and ∆H, and ∆G. Gases evolved during pyrolysis were qualitatively analyzed by FTIR to see the effect of catalyst on evolved gas composition during the pyrolysis process.

In this study, three kinds of amide functional group modified hyper-cross-linked adsorption resin were synthesized by alternating radical copolymerization in simple one-step and applied for 5-hydroxymethylfurfural (5-HMF) adsorption. The successful synthesis and properties of adsorbents were evaluated with Fourier transform infrared spectroscopy, scanning electron microscopy, nitrogen adsorption–desorption isotherms, thermogravimetric analysis, and elemental analysis. Poly (N, N’-4,4’-diphenylmethane-bismaleimide-alt-divinylbenzene) (poly (BDM-alt-DVB)) resin exhibited highest adsorption capacity for 5-HMF (64.0 mg·g–1 wet resin) and excellent adsorption selectivity (α5-HMF/LA=2.71±0.12, α5-HMF/FA=13.88±0.15, α5-HMF/Glucose=11.91±1.11) in the multi-component solution at 25 °C. Langmuir isotherm model well fitted the equilibrium adsorption data within the initial 5-HMF concentration range of 0.5–10.0 g·L–1 with highest correlation coefficient. Furthermore, the thermodynamic parameters demonstrated that the adsorption of 5-HMF onto poly (BDM-alt-DVB) resin was spontaneous and exothermic. Kinetic study revealed that the adsorption process was fast, reaching equilibrium within 12 min. Importantly, the poly (BDM-alt-DVB) resin also demonstrated excellent reusability. In summary, the poly (BDM-alt-DVB) resin will be useful in 5-HMF hydrolysate separation applications.

Hydrogenation of aldehydes (RHO) is one of the frequently used reactions in organic synthesis and pharmaceuticals industries. In this contribution, we have synthesized control shaped and nano-sized tetragonal zirconia (t-ZrO2), palladium supported on zirconia (Pd/t-ZrO2) and nickel promoted palladium supported on zirconia (Ni-Pd/t-ZrO2) though modified microwave irradiation method. All the prepared samples were characterized by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Diffractometry (XRD), Thermal Gravimetric Analysis (TGA), Brunauer-Emmett-Teller (BET) surface area and pore size analysis, and Fourier Transform Infrared Spectroscopy (FT-IR). Theoretical calculation (DFT) revealed high interaction of Pd with t-ZrO2(101) surface. Furthermore, adsorption energy, support relaxation and charge transfer studies confirmed the stability of Pd on t-ZrO2(101) surface. The catalytic activity of catalysts was tested for cinnamaldehyde (CAL) hydrogenation in a modified microwave reactor. The comparative study of microwave irradiated (MW) and conventional heating (C-Heating) systems show supremacy of MW over C-Heating by a factor of 46% under optimal reaction parameters for Pd/t-ZrO2 catalyst. The stability, life span, conversion and selectivity of Pd/t-ZrO2 under MW system suggest the applicability of the catalysts for a variety of organic hydrogenation reactions.

In the present work, Olive Husk (OH) waste is successfully utilized to produce cellulose by degreasing, eliminating hemicelluloses, and bleaching with a 74% yield. Fourier transform infrared spectroscopy (FTIR) analysis is used to characterize the structural properties of OH and cellulose samples. FTIR depicts the transmission peak 1745, 1375 and 1260 cm−1 due to wax, hemicellulose and lignin respectively. The thermal stability of OH and extracted cellulose was investigated by thermogravimetric analysis (TGA). The extracted cellulose had good thermal stability, the degradation temperature of the extracted cellulose.

Dianhydride (3′, 4, 4′-biphenyltetracarboxylic dianhydride (BPDA) and Diamine (p-phenylediamine (PDA) in a ratio of 1:1 polymerize Polyimide (PI) in N-Methyl-2-Pyrrolidone (NMP) as solvent. A series of PI films were made in presence of BPDA and two types of Diamines (PDA and HAB (4, 4′-Diamino-3, 3′-dihydroxybiphenyl) where Diamines ratios were 95:5, 90:10, 80:20, 50:50, 0:100. HAB was introduced as source of benzoxazole. Fourier transform infrared (FTIR) confirmed that there was benzoxazole ring in polyimide after curing. FTIR, Differential scanning calorimetry (DSC), UV-spectrophotometer, Scanning electronic microscope (SEM), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and stress-strain tests were used to measure the performance of the films. The results indicated that small content of benzoxazole (5%) increase thermal stability, glass transition temperature and tensile strength prominently than the pristine PI which may use for microelectronics.

In the present communication, we have synthesized iron oxide nanoparticles through a greener method. The adopted method is highly efficient because of its sustainable and eco- friendly approach. The conventional routes of synthesis require high temperature and large volume of solvents which are not suitable for environment applications. The adopted method is applied to synthesize magnetic and optical iron oxide nanoparticles. The iron oxide nanoparticles were prepared using the water extract of Hylocereus undantus (pitaya) which acts as a reducing agent. The as obtained nanoparticles obtained were characterized through PXRD (Powder X-ray Diffraction), UV–Vis (Ultraviolet– Visible Spectroscopy), TEM (Transmission electron microscopy), SAED (Selected Area Electron Diffraction), FT-IR (Fourier transform infrared spectroscopy), DLS (Dynamic Light Scattering) and TGA (Thermogravimetric analysis). According to various methods of characterization, it was revealed that the nanoparticles were spherical in shape and the size were in the range of 10–15 nm. The major lattice planes present in the synthesized crystalline iron oxide nanoparticles were known through XRD and SAED. The synthesized nanoparticles were uniform in size as revealed through DLS. TGA was performed to testify the degradation of nanoparticles under high temperatures. So, the iron oxide nanoparticles formed were spherical, uniform, ultrafine, reusable and magnetic in nature.

The performance of composites reinforced with natural fibers increases depending on the nature of the fibers and the type of surface treatment applied to the fibers. To improve the interfacial properties of the naturel fibers, one of natural fibers was selected (Wood Flour (WF)) and we introduced Graphene oxide (GO). The hydrogen bonding interactions between the Wood Flour and the GO facilitate the dispersion of the latter on the surface of the fibers to gives composite fibers (WF/GO). Several characterization techniques including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA) and Scanning electron microscopy (SEM) have been used to study the structural, thermal stability and morphological properties of the prepared hybrid composite. Morphological analysis revealed that the applied surface treatment of the Wood Flour (WF) was efficient where a good distribution of the GO sheets on the fiber interface is detected.

This study investigated the influence of the torrefaction process on thermal degradation and chemical changes of oil palm solid waste (OPSW) through thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) analysis. Palm kernel shell (PKS) showed the highest mass and energy yield after the torrefaction process. Furthermore, torrefied PKS (TPKS) showed the highest heating value (23.10 MJ/kg). Weight loss in active pyrolysis stages was reduced after the torrefaction, thus indicates the lignocellulosic component decomposition. OPSW showed a reduction in hydroxyl group (−OH) after torrefaction resulting in hydrophobicity characteristic. Torrefaction has significantly enhanced the characteristics of OPSW as solid biofuel.

A novel Cu (II) based coordination polymer [Cu(ipa)(py)3]n (1) (ipa = Isophthalic acid) has been synthesized from isophthalate and heterocyclic pyridine ligand and was well characterized by Fourier Transform Infrared Spectroscopy and Single Crystal X Ray Diffraction (SCXRD). Phase purity of the compound was analysed by powder X ray Diffraction (PXRD). The thermal behaviour of the compound was also studied by Thermogravimetric analysis (TG) which revealed the thermal stability of synthesised compound over a wide temperature range. SCXRD studies revealed the compound to be a 1D-coordination polymer with asymmetric unit belonging to monoclinic crystal system with space group P 2(1)/n [a = 9.1209(2), b = 15.3603(3), c = 16.0084(3), α = 90.00, β = 92.2250(10), γ = 90.00] and the central atom Cu (II) possessing a triagonal bipyramidal based geometry.

Biodegradable and eco-friendly adsorbents composed of natural carbohydrates have been used to replace carbon-based materials. This study presents a natural carbohydrate-based chitosan/pectin (CS/Pec) hydrogel adsorbent to remove Pb(II) from aqueous solutions. The physical CS/Pec hydrogel was prepared by blending aqueous CS and Pec solutions at 65 °C, preventing the use of toxic chemistries (crosslinking agents). The thermosensitive CS/Pec hydrogel was quickly created by cooling CS/Pec blend at room temperature. The used strategy created stable CS/Pec hydrogel against disintegration and water dissolution. The as-prepared hydrogel was characterized by infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The adsorbent had 1.688 mmol -COO− for each gram. These ionized sites bind Pb(II) ions, promoting their adsorption. The adsorption kinetic and equilibrium studies indicated that the Elovich and pseudo-second-order models adjusted well to the experimental data, respectively. The maximum removal capacities (qm) predicted by the Langmuir and Sips isotherms achieved 108.2 and 97.55 mg/g at 0.83 g/L adsorbent dosage (pH 4.0). The hydrogel/Pb(II) pair was characterized by scanning electron microscopy (SEM), X-ray dispersive energy (EDS), and differential scanning calorimetry (DSC). The chemisorption seems to play an essential role in the Pb(II) adsorption. Therefore, the adsorbent was not recovered, showing low potential for reusability.

The capability to recycle waste materials, such as steel slag, has appealed to the construction industry, as the cement industry faces a major challenge to reduce carbon dioxide (CO2) emissions into the atmosphere. This paper investigated the obtainment of cement pastes with Kanbara reactor desulfurization waste slag (KR slag) through alkaline activation using silicate and sodium hydroxide solutions. The mixtures were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), compressive strength, and physical property tests. The FTIR, XRD, and TGA results pointed to chemical activation, forming C-S-H and C-(A)-S-H gels. The formation of these compounds indicated the possibility of using KR slag in cementitious composites for civil construction.

The encapsulation of phase change materials (PCMs) with typical core-shell structures is considered an effective and accessible technology to prevent liquid leakage and minimize the corrosion of PCMs. However, the poor solar-thermal conversion performance and significantly reduced energy storage density of microencapsulated PCMs seriously restrict their large-scale application. Herein, novel double-layered organic phase-changing microcapsules that contain n-eicosane as core material and polydopamine/poly(melamine-formaldehyde) resin (PDA@MF) as shell materials were designed and fabricated via a two-step polymerization. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the successful fabrication of the PDA@MF/n-eicosane microencapsulated phase change materials (PMPCMs), which exhibited a regular, spherical shape. Differential scanning calorimetry (DSC) results showed that PMPCMs possessed extremely high phase change enthalpies (PMPCM-85, 199.4 J/g) and excellent thermal durability. Solar irradiation experiments showed that the introduction of PDA effectively improved the solar-thermal conversion efficiency of PMPCMs. Thermogravimetric analysis (TGA) and thermal reliability measurements demonstrated that the developed microcapsules exhibited good thermal reliability and stability. Furthermore, the introduction of PDA can significantly reduce the leakage rate of the microcapsules and strengthen the shell layer of the microcapsules. In conclusion, the double-layered PMPCMs expressed tremendous potential for efficient solar energy storage.

In this study, NH2-MIL-101(Al) metal-organic frameworks (MOFs) covered with 3-aminopropyltriethoxysilane (APTES) were incorporated into the polyethersulfone (PES) to produce mixed-matrix membranes (MMMs) for CO2 separation. The APTES functionalization was performed to improve the MOF dispersion in the PES matrix. Different analyses such as X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM) revealed that the MOFs surface successfully functionalized with APTES. An improvement in CO2/CH4 separation efficiency was observed in MMMs, and the performance shifted towards Robeson upper bounds. Notably, the membrane containing 10 wt.% S-MIL-5 (NH2-MIL-101(Al) functionalized with 5.0 mL of APTES) showed an increment in CO2 permeability (50%), and ideal CO2/CH4 selectivity (80%) compared to the PES membrane. The FTIR, TGA, FESEM, and DSC analyses constituted an excellent dispersion of MOFs within the PES phase, which led to significant development in gas permeability and selectivity.

Carbon aerogel (CA) was prepared using the cellulose extracted from luffa sponge (LS). Trichlorosilane was employed to modify CA to enhance the adsorption capacity for diesel oil. The physical and chemical properties of aerogel, CA and modified CA were analyzed using XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), FTIR (Fourier Transform infrared spectroscopy), SEM (scanning electron microscope) and TGA/DTG (Thermogravimetric analysis/Derivative Thermogravimetry). Modified carbon aerogel (MCA) had better adsorption capacity for diesel oil (49.62 g/g) than aerogel (5.2 g/g) and CA (32.34 g/g). In addition, the adsorption capacity of MCA for other organics was also investigated, which indicated the abroad application scope for MCA. The reuse method (burning, suction filtration and pyrolysis) for diesel oil adsorption using MCA was investigated and pyrolysis shown the optimal effect for MCA regeneration. The cycle times of MCA for diesel oil adsorption was studied using pyrolysis to regenerate MCA and MCA still had good adsorption capacity for diesel oil (45.14 g/g) in the sixth use. This paper provides a novel strategy for resource utilization of LS and a fast and green method for diesel oil treatment.

A thermal protection material (TPM) was prepared using Al2O3-phosphate, expanded aluminosilicate, and phenolics through compression molding and the gradient heating reaction technique, and the effect of the high-temperature treatment on the properties of the composites were investigated. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy were used to analyze the structures and compositions of the composites. After the high-temperature treatment, the composites exhibited increased porosity, decreased density, and generated SiC particles with high strength and temperature resistance. The prepared composites have high compressive strength and compression deformation ability of the bending point. Thermogravimetric analysis, coefficient of thermal conductivity measurements, and expansion analysis were carried out to evaluate the thermal properties of the composites, and the effects of the preparation conditions on the thermal properties of the composites were investigated. The results showed that the prepared composites exhibited complete morphology, excellent high-temperature resistance, high compressive strength and toughness, and low thermal conductivity before and after the high-temperature treatment at 1000 °C, and hence showed great potential for future thermal protection applications.

The present work describes comparative study of annealing temperature in the range of 500–900 °C on the successful synthesis of Gd/Mn2SnO4 nanocomposite via sol gel method followed by hydrothermal method. Structural, optical, photoluminescence, photocatalytic activities against methylene blue and methyl orange; and antifungal features against Aspergillus niger of Gd/Mn2SnO4 nanocomposite were studied. The structural and optical properties were investigated using X-ray diffraction (XRD), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FTIR), UV–Visible spectroscopy and particle size analyzer (PSA) techniques. Crystallite size, particle size and optical band gap were calculated using XRD, PSA and Uv–visible spectroscopy, respectively. Gd/Mn2SnO4 nanocomposite annealed at 500 °C is found to be a competent photo catalyst for degradation of dyes used for the study and for the growth inhibition of Aspergillus niger.

Batch adsorption experiments were carried out to eliminating Congo red (CR) and methylene blue (MB) from aqueous solution using oxalic acid-modified jujube shells of Ziziphus lotus (OA-JS)/ZnFe2O4(OA-JS@ZnFe2O4) nanocomposite as a high efficient adsorbent. The Fourier transform infrared (FTIR), Brunauer Emmett Teller, thermogravimetric analysis–differential scanning calorimetry, scanning electron microscope, transition electron microscope, and X-ray diffraction techniques were used to characterize the OA-JS@ZnFe2O4. The equilibrium data fitted to Langmuir isotherm and the maximum adsorption capacities were determined as 980.39 mg g−1 and 476.18 mg g−1 for CR and MB, respectively. The pseudo-second-order model could be best described the sorption kinetics. The calculated thermodynamic suggests that the CR and MB adsorption on OA-JS@ZnFe2O4 is spontaneous and endothermic. The OA-JS@ZnFe2O4 recycled, and the removal CR and MB were 82.08% and 76.59% after seven cycles, respectively. The synthesis of OA-JS@ZnFe2O4 nanocomposite showed excellent potential adsorbent for dye removal from wastewaters.

In this paper, structure, chemical composition and physicochemical properties of the novel polysaccharide Amuniacum gum (AMG) were assessed. The AMG had 12.21% moisture, 3.76% ash, 0.31% protein, 73.06% carbohydrate, 1.24% fat and 10% uronic acids. The elemental analysis indicated the absence of sulfur. The HPLC demonstrated the presence of galactose and arabinose as dominant sugars. The X-ray diffraction (XRD) pattern of the native gum indicated a semicrystalline structure. Furthermore, gel permeation chromatography (GPC) showed that the average molecular weight included 35 kDa. The Fourier transform infrared (FTIR) spectroscopy showed the presence of hydroxyl, carboxyl and methyl groups. Moreover, 1H and 13C NMR analysis demonstrated that AMG included a backbone of β-D-Galp residues and was mainly branched through 4-O-methyl-α-D-glucopyranosyl units. Results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated that the thermal decomposition of AMG occurred at nearly 278 °C. In conclusion, these results highlight that the novel gum can be used in food and pharmaceutical industries.

There is a growing demand for biopolymers for packaging, dietary fiber, and as a food additive, where nanocellulose has become an important material for such purposes. In this study, a process utilizing successive steps in the same container was used, avoiding washing and neutralization between stages, showing nanocellulose isolation using a brown alga with a yield of 14.9%. Transparent films of pure 2D nanocellulose were prepared by the cast evaporation method, using Sargassum spp. as a raw material in a one-pot innovative process. Thermogravimetric analysis shows the presence of non-cellulosic components within the Sargassum and also the presence of nanocellulose at the end of the process. The obtained material was characterized by FTIR, NMR, and UV–Vis spectrophotometry, showing that the cellulose was successfully isolated, generating films with a transmittance of 81%. Finally, laser scanning microscope and the scanning electron microscope results corroborated the presence of cellulose nanoplatelets made of cellulose nanofibers with a thickness of ≈100 nm which explains the optical properties, such as the transmittance and constructive interference that facilitates characterization with a simple optical microscope.

The most important role of tissue engineering is to develop a biomaterial with a property that mimics the extracellular matrix (ECM) by enhancing the lineage-specific proliferation and differentiation with favorable regeneration property to aid in new tissue formation. Thus, to develop an ideal scaffold for bone repair, we have fabricated a composite nanofiber by the coaxial electrospinning technique. The coaxial electrospun nanofiber contains the core layer, consisting of polyvinyl alcohol (PVA) blended with oregano extract and mesoporous silica nanoparticles (PVA-OE-MSNPs), and the shell layer, consisting of poly-e-caprolactone blended with collagen and hydroxyapatite (PCL-collagen-HAP). We evaluated the physicochemical properties of the nanofibers using X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). In vitro biocompatibility, cell adhesion, cell viability, and osteogenic potential were evaluated by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenlytetrazolium bromide (MTT), calcein AM, and alkaline phosphatase (ALP) activity and Alizarin Red staining in NIH 3T3/MG-63 cells. The results showed that the nanoparticle-incorporated coaxial nanofiber was observed with bead-free, continuous, and uniform fiber morphology with a mean diameter in the range of 310 ± 125 nm. From the biochemical studies, it is observed that the incorporation of nanofiber with HAP and MSNPs shows good swelling property with ideal porosity, biodegradation, and enhanced biomineralization property. In vitro results showed that the scaffolds with nanoparticles have higher cell adhesion, cell viability, ALP activity, and mineralization potential. Thus, the fabricated nanofiber could be an appropriate implantable biomaterial for bone tissue engineering.

International audience; In order to study the release of cerium nitrate in a self-healing epoxy-based coating, poly (urea-formaldehyde) (PUF) microcapsules containing cerium nitrate were synthesized. The effects of healing agent concentration and weight percent of microcapsules in the epoxy resin were studied through the incorporation of microcapsules within an epoxy-based coating. The prepared microcapsules were characterized using thermogravimetric analysis and Fourier transform infrared spectroscopy and confirmed the successful encapsulation of cerium nitrate within PUF capsules. The self-healing performance of the prepared epoxy coating was investigated in 0.6 M NaCl solution using electrochemical impedance spectroscopy (EIS) tests. The EIS results indicated the successful release of encapsulated cerium nitrate from PUF microcapsules once the damage occurred in the epoxy coating, which led to effective self-healing of the epoxy-based coating. The presence of chlorine and cerium ions in the solution led to the precipitation of cerium hydroxides and oxides in the scratched area as a passive layer which hindered the corrosion in the damaged area. In addition, the EIS results showed that the healing performance of the coatings depends on the weight percent of microcapsules and the concentration of the self-healing agent. The highest self-healing performance was achieved for the maximum amount of microcapsule incorporation (10 wt %), while the increase in the microcapsule percent led to a decrease in the adhesion of the coating to the substrate.

Finding novel systems for controlled delivery of drugs is still a stringent need. Fabrication of drug delivery systems (DDS) having a cross-linked low molar mass synthetic polycation such as poly(ethylene imine) (PEI) entrapped into the pores of a mesoporous silica followed by coating the silica/PEI composite microspheres with a pH responsive layer-by-layer (LbL) film is presented for the first time in this work. The LbL film, which behaves as drug release lingering component of the composite, was constructed with carboxymethyl cellulose (CMC) and chitosan (CS) as building blocks. Silica/PEI/(CMC/CS)n composites were fully characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and EDX spectra, and by the nitrogen sorption/desorption isotherms (BET analysis). The dynamic of LbL film construction was followed by potentiometric and polyelectrolytic titrations. Diclofenac sodium (DS) was used as a model drug to demonstrate the potential of the as prepared composite as novel system for controlling the release of drugs. Investigation of the release kinetics evidenced the influence of the LbL film on the mechanism of DS release. Taking into account the values of nr in the Korsmeyer-Peppas equation, pseudo-Fickian release, with nr

The design and development of new catalysts with low cost, high selectivity, and sensitivity for the electrochemical sensor applications is of huge interest. In this report, novel zinc tetra [4-[2-(1H-benzimidazol-2-yl) phenoxy]] phthalocyanine (ZnTBImPc) is prepared in a pure state with 87% yield. The characterization of the ligands and complex is carried out by combination of techniques like elemental analysis, ultraviolet–visible (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), mass spectral, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and electrochemical techniques. FTIR is useful in monitoring the progress of the reaction. The benzimidazole moiety of ZnTBImPc undergoes electropolymerization and thin, uniform polymeric layer deposits on the glassy carbon surface. The polymeric film was characterized by impedance spectra and charge transfer studies. The fabricated polymeric film electrode is applied for voltammetric sensing of ammonia which showed linear characteristics in 0.1 to 1.0 µM concentration range. The LOD was 30 nM with sensitivity of 237.25 µA µM−1 cm−2. The efficiency and sensitivity of ammonia oxidation at the poly(ZnTBImPc) are compared with the composite hybrid electrode of poly(ZnTBImPc) and carbon nanoparticle (CNP). The amperometric sensing of ammonia showed linear behavior in 50 to 500 nM concentration range. The RDE experiment revealed that the number of electrons involved in the ammonia oxidation is nearly 3. The polymeric electrode was subjected to the interference studies to evaluate the selectivity of the fabricated electrode and found that the co-existing molecules do not show interference during the detection of ammonia. Schematic representation of electro-oxidation and detection of ammonia

Composite biomaterials based on hydrogel biopolymers and bioactive ceramic fillers are highly attractive to wound dressing applications due to the enhanced swelling properties of hydrogel towards blood and exudates and the tissue regeneration provided by inorganic fillers. This study highlights the fabrication of Chitosan-Hyaluronic Acid-Biosilicate® (CHI-HA-BioS) composite films as a matrix for wound healing applications. Firstly, a protocol to prepare the CHI-HA-BioS composite by solvent casting was assessed. Then, the films were characterized by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM); in addition, in vitro tests were conducted to evaluate their equilibrium water content (EWC), bioactivity, and cytotoxicity. The results showed that the protocol enabled the incorporation of HA into the CHI-BioS structure of the composite, increasing its EWC and cell cytocompatibility, but reducing its bioactivity. Therefore, the characterizations of the material validated the protocol and demonstrated its efficiency. The CHI-HA-BioS composite has great potential for biomedical applications, especially in the development of dermal wound dressings.

Immobilization of inorganic metal quantum dots (especially, noble transition metals) onto organic polymers to synthesize nanometal-polymer composites (NMPCs) has attracted considerable attention because of their advanced optical, electrical, catalytic/photocatalytic, and biological properties. Herein, novel, highly efficient, stable, and visible light-active NMPC photocatalysts consisting of silver quantum dots (Ag QDs) immobilized onto polymeric chitosan-polyethylene oxide (CTS-PEO) blend sheets have been successfully prepared by an in situ self-assembly facile casting method as a facile and green approach. The CTS-PEO blend polymer acts as a reducing and a stabilizing agent for Ag QDs which does not generate any environmental chemical pollutant. The prepared x wt % Ag QDs/CTS-PEO composites were fully characterized through X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis, and UV/visible spectroscopy. The characterization results indicated the successful synthesis of the Ag QDs/CTS-PEO composites by the interactions and complexation between x wt % Ag QDs and CTS-PEO blend sheets. TEM images revealed small granules randomly distributed onto the CTS-PEO blend sheets, indicating the immobilization of Ag QDs onto CTS-PEO composites. The presence of a surface plasmon resonance (SPR) band and the shifting of the absorption edge toward higher wavelengths in the UV/vis spectra indicated the formation of x wt % Ag QDs/CTS-PEO composites. The Ag QDs in the polymeric blend matrix led to remarkable enhancement in the optical, thermal, electrical, and photocatalytic properties of x wt % Ag QDs/CTS-PEO composites. The photocatalytic efficiency of the prepared composites was evaluated by the photodegradation of p-nitrophenol (PNP) under simulated sunlight. The maximum photocatalytic degradation reached 91.1% efficiency within 3 h for the 12.0 wt % Ag QDs/CTS-PEO photocatalyst. Generally, the Ag QDs immobilized onto CTS-PEO blend composites significantly enhance the SPR effect and the synergistic effect and reduce the band gap, leading to a high photocatalytic activity.

This paper presents the results obtained from the thermal analysis of a set of geomaterials (clays, pyroclastic materials, and industrial recycled materials) to be used as raw materials for the synthesis of geopolymers, specifically designed for the conservation of Cultural Heritage (CH) buildings, particularly in seismic hazard zones such as Sicily. X-ray diffraction and gas volumetric analysis (calcimetry) were applied to this set of raw materials in order to characterize the materials from the chemical and structural point of view. Thermogravimetric analysis (TG), TG coupled to Fourier transform infrared spectroscopy (TG-FTIR), and differential scanning calorimetry were used to characterize their thermal behavior. The statistical treatment of the thermogravimetric data by principal component analysis and hierarchical clustering analysis highlights the direct relation between the thermal data and the material composition that will be exploited for the selection of the best materials to obtain geopolymers specifically designed for the conservation of CH buildings.

In this project, pseudo-poly(amino acid)s (PAAs) containing different amino acids in main chain were synthesized by direct polyesterification of N,N-(pyromellitoyl)-bis-D-4-hydroxyphenylglycine dimethyl ester as biologically active diol with diacid monomer derived from different amino acids was carried by tosyl chloride/pyridine/N,N′-dimethylformamide as a condensing agent. All biological properties of the polymers were determined by biological evaluation in bacterial media. PAAs containing silver nanoparticles were fabricated by in situ method using dimethylformaide (DMF) as a solvent which leads to a spontaneous reduce in room temperature. Furthermore, these biopolymer nanocomposite/Ag thin films were immobilized on glass microbeads. The chemical structures of synthesized PAAs and PAA/Ag nanocomposite (NC) were considered by FTIR, 1H-NMR spectroscopy, transmission electron microscopy (TEM), elemental analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy, and energy dispersive X-ray (EDAX). The results of EDAX and TEM analysis of PAAs/Ag NC showed that silver particles have homogeneous dispersion and uniformity in nano-dimensions about 50 nm in PAAs matrix. The micro glass beads were coated with PAA/Ag nanocomposite thin film and placed in a column through for the disinfecting effect of Escherichia coli in water was evaluated very well.

In this study, a chitosan-based bioflame retardant additive (referred to as NCS) was prepared by chemically altering CS with silicon dioxide (SiO2) via an ion interchange reaction. The effect of NCS on the thermal stability and mechanical properties of vinyl ester/bamboo fiber (VE/BF) composites was studied. The composites were manufactured by a vacuum-assisted resin transfer molding (VARTM) process. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy and X-ray diffraction analysis were used to characterize the NCS. The spectral results revealed a new peak at 1560 cm−1 corresponding to NH3+–−O Si, indicative of bond between CS and SiO2. The SEM, and XRD results showed a diverse morphology (coarse surfaces) and a significant decrease in the intensity of the diffraction patterns, respectively, which further supported the formation of NCS. The heat release rate (HRR) of NCS was observed to decrease significantly by 76%, and the residual char content increased by 47% compared with CS. The flame retardant and thermal behavior of the NCS-VE/BF composites were examined by UL-94 standards, microcalorimetry, and cone calorimetry and thermogravimetric analysis (TGA). The results showed a 32% delay in burning time, a 14% enhancement in the limiting oxygen index (LOI), and an 18% decrease in the peak heat release rate (pHRR) and total heat release rate (THR) after incorporation of NCS in the VE/BF composites. The addition of NCS into the VE/BF composites also resulted in improved the mechanical properties of the composites, including the tensile, flexural and impact properties. Overall, the synthesized NCS proved to be suitable for the fabrication of sustainable flame-retardant natural fiber (NF) composites suitable for substructural parts in engineering applications without deterioration of mechanical properties.

Aerosol forming composite (AFC) is an important component of condensed aerosol-based fire extinguishing system (CAFES). As per literature no attempts have been made so far for the detailed study of AFCs. Therefore, for the insight AFCs were prepared with potassium nitrate as an oxidizer and phenol formaldehyde resin as a combustible binder. Five metal oxides, namely MnO2, Fe2O3, NiO, CuO and CeO2, (3%, w/w) were added as catalysts in AFC. The catalytic effect of these metal oxides was investigated for various parameters such as combustion efficiency, burn rate, minimum fire extinguishing concentration (MEC), decomposition temperature and activation energy. Addition of CuO, 3%, w/w increased the burn rate of AFC by 51.4% and reduced the MEC by 29.4%. Thermogravimetric analysis and differential scanning calorimetry analysis clearly indicated the reduction in decomposition temperature from 445.65 to 396.48 °C while adding CuO. Activation energies of decomposition for base AFC and AFC-CuO calculated using model-free methods of Kissinger, Ozawa–Flynn–Wall and Kissinger–Akahira–Sunose were found to be 181.12, 183.50 and 180.75 kJ/mol and 146.61, 149.98 and 163.18 kJ/mol, respectively. The functions 1−(1−α)2/3 (model F1/3: One-third order) and [1−(1−α)1/2] (model R3, F2/3: power law) were found as the most probable mechanism for the thermal decomposition of base AFC and CuO-AFC, respectively. Aerosol characterization with X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and particle counter indicated mostly 2 µm particles of potassium carbonate/bicarbonate. Total flooding and dispersion characteristics of aerosols were confirmed using pH measurements at various locations. Overall, prepared AFCs were found promising for use within CAFES.

In this work, new bio-based copoly(ester amide)s were synthesized by a two-step melt polycondensation process, using 2,5-furanedicarboxylic acid dimethyl ester (DMFDC), 1,3-propanediol (PDO), and 1,3-diaminopropane (DAP), with different DAP content. The chemical structure of the obtained poly(trimethylene 2,5-furandicarboxylate)-co-poly(propylene furanamide) (PTF-co-PPAF) copolymers was confirmed by nuclear magnetic resonance (1H NMR) and Fourier-transform infrared (FTIR) spectroscopy. Gas chromatography/mass spectrometry was used to provide more details of the polycondensation process. Thermal properties of the obtained materials were characterized by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic–mechanical thermal analysis (DMTA). The copolymers were amorphous and their glass transition temperature increased with the increase in the poly(propylene furanamide) (PPAF) content. The synthesized PTF-co-PPAF copolymers exhibited improved thermal and thermo-oxidative stability up to 300 °C. In addition, from the performed mechanical tests, it was found that along with the increase in PPAF content, Young's modulus increased, while at the same time, the value of elongation at break decreased. Graphical Abstract

A novel arginine-modified Heliotrope leaf (Arg@HL) was used as adsorbent for the crystal violet (CV) dye adsorption in a batch process. The physicochemical and morphological composition of Arg@HL were characterized by field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The experiments were carried out to investigate the factors that influence the dye uptake by the adsorbent, such as the contact time under agitation, adsorbent amount, initial dye concentration, temperature and pH of dye solution. The optimum conditions of adsorption were found on the batch scale as followed: CV concentration of 20 mg·L−1, an amount of 0.75 g·L−1 of the adsorbent, 90 min contact time, 6 pH and 25 °C temperature for Arg@HL. The results confirmed a second-order model explaining the dye crystal violet's adsorption's kinetics by Arg-Heliotrope leaves. The Langmuir model effectively defines the adsorption isotherms. The results revealed that the Arg@HL has the potential to be used as a low-cost adsorbent for the removal of CV dye from aqueous solutions. HIGHLIGHTS The first effort to use a low-cost arginine-modified Heliotrope leaves material as an adsorbent for crystal dye elimination by adsorption procedures.; CV dye was efficiently removed using Arg@HL.; Arg@HL exhibited high adsorption capacity for CV dye.; Adsorption process follows the Langmuir isotherm.

Sodium lignosulfonate/chitosan-glutaraldehyde adhesive (L/C-G) has potential in environment-friendly wood-based panel adhesive applications. However, the effect of sodium lignosulfonate on the bonding strength and chemical structure of L/C-G was not elucidated. Herein, the role of sodium lignosulfonate in L/C-G was studied in detail by characterizing the mechanical properties and water resistance of medium-density fiberboards (MDFs) prepared using L/C-G as adhesives. The functional groups, thermal stability, and crystalline structure of L/C-G with various mass ratios of sodium lignosulfonate to chitosan were also characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction, respectively. The results show that an appropriate amount of sodium lignosulfonate in L/C-G was beneficial for its bonding strength, and the MDFs with 1:2 mass ratio of sodium lignosulfonate to chitosan showed superior mechanical properties and comparable water resistance with a commercial panel. Besides the reaction between sodium lignosulfonate and chitosan, guaiacyl units, or lateral chain of sodium lignosulfonate might also react with glutaraldehyde and result in C–O–C groups, helpful for the bonding strength of L/C-G.

This work presents a cost-effective approach for processing of renewable carbon-rich biomass using pyridinium-based Lewis acidic ionic liquids (LAILs). Rice husk as carbon-rich lignocellulosic waste was pretreated with a series of neutral and Lewis acidic ionic liquids to yield valuable intermediate platform monosaccharides. Novelty in the work lies in direct conversion of lignocellulosic carbohydrates into reducing sugars without their further conversion into 5-hydroxymethylfurfural or any other platform chemicals that are fermentation inhibitors for bioethanol production. The unconverted cellulose-rich material (CRM) is regenerated as a delignified material by the simultaneous addition of antisolvents. CRM and recovered lignin obtained after pretreatment were analyzed via scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. The process was optimized with respect to a high yield of platform sugars and the quantity as well as quality of recovered CRM and lignin contents. Various reaction parameters involving the molecular structure of ionic liquids (ILs), Lewis acidic strength of ILs, biomass loading into IL, time, temperature, and biomass particle size were screened thoroughly. From all of the tested ILs, unsymmetrical 3-methylpyridinium IL having N-octyl substitution and chloroaluminate anion showed a greater conversion efficiency at 100 °C for 1.5 h. FTIR and SEM analyses of recovered CRM justify >90% lignin removal from rice husk. From all of the removed lignin, 60 wt % of original lignin content was recovered. The Lewis acidic system possessed recycling ability up to 3 times for subsequent treatment of rice husk without a significant loss of efficiency.

Polymer microspheres with inter-connecting pores are widely used as microsphere materials. In the study, the ethyl cellulose microspheres (ECM) were prepared by using the solvent-evaporation method. Based on that, a method for the separation and purification of benzoic acid from crude extract of Cyclocarya paliurus was established by the ECM and high performance liquid chromatography (HPLC). The ECM after the sorption equilibrium was desorbed by using 40% methanol as the analytical solvent. The content of benzoic acid in eluent is up to 0.0216 mg/mL, and the benzoic acid can be obtained with a high purity of 82.22%. Furthermore, the adsorption-desorption behavior of benzoic acid onto ECM was investigated. The results of adsorption kinetics of benzoic acid showed that the adsorption followed the pseudo-first-order kinetic model. The ECM was characterized by using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and X-ray diffraction (XRD). The results showed that the ECM has a high adsorption property due to its more porous structure, phenolic hydroxyl group, and other oxygen-containing functional groups. This method and the ECM can be used stably, continuously, and efficiently to purify the benzoic acid from the methanol extract of C. paliurus on a large scale.

Casein (CS) and graphene oxide (GO) were employed for the fabrication of a casein/graphene oxide (CS/GO) aerogel by vacuum freeze drying. Fourier transform infrared spectroscopy, scanning electron microscopy, surface area and micropore analysis (BET), and thermogravimetric analysis were used to characterize the specific surface area, structure, thermal stability, and morphology of the CS/GO aerogel. The influence of experimental parameters such as the GO mass fraction in the aerogel, metering of the adsorbent, pH, contact time, and temperature on the adsorption capacity of the CS/GO aerogel on methylene blue (MB) was also investigated. According to Langmuir isotherm determination, the maximum removal rate of MB from the CS/GO aerogel was 437.29 mg/g when the temperature was 293 K and pH was 8. Through kinetic and thermodynamic studies, it is found that adsorption follows a pseudo-second-order reaction model and is also an exothermic and spontaneous process.

Hydrochar a carbon-rich material resulting from hydrothermal carbonization of biomass, has received substantial attention because of its potential application in various areas such as carbon sequestration, bioenergy production and environmental amelioration. A series of hydrochars were prepared by metal chloride-assisted hydrothermal carbonization of rice husk and characterized by elemental analysis, zeta potential, X-ray diffraction, Brunauer–Emmett–Teller measurements, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and scanning electron microscopy. The results reveal that the prepared hydrochars have carbon contents ranging from 45.01 to 58.71%, BET specific areas between 13.23 and 45.97 m2/g, and rich O-containing functional groups on the surfaces. The metal chlorides added in the feedwater could improve the degree of carbonization and show significant effects on the physical, chemical and adsorption properties of the hydrochars. The adsorption of the selected organics on the hydrochars is a spontaneous and physisorption-dominated process. The hydrochars possess larger adsorption capacities for 2-naphthol than for berberine hydrochloride and Congo red, and the modeling maximum adsorption capacities of 2-naphthol are in the range of 170.1–2680 mg/g. The adsorption equilibrium could be accomplished in 10, 40 and 30 min for 2-naphthol, berberine hydrochloride and Congo red, respectively. These results suggest metal chloride-assisted hydrothermal carbonization a promising method for converting biomass waste into effective adsorbents for wastewater treatment.

Four bioactive glasses (70 SiO2-(20-X) CaO-10 P2O5) containing low concentrations of silver (X Ag2O; where X = 0.5, 1, and 1.5 mol%) were synthesized by the conventional sol-gel method. Physical and structural characterization was realized using Fourier Transform Infrared (FT-IR), Thermogravimetric Analysis (TGA), X-ray Diffraction analysis (XRD), and Scanning Electron Microscopy (SEM-EDX). Acellular bioactivity tests were performed by immersion in the SBF solution. Escherichia coli and Staphylococcus aureus were used to evaluate the antibacterial activity of the prepared Ag-doped bioglasses. While FTIR, DRX, and SEM analysis displayed good acellular bioactivity for all bioactive glasses (Ag–70S), the antibacterial activity confirms well the bactericidal effect of 70S 1Ag and 70S 1.5Ag through total growth inhibition (100%) of the two pathogenic bacteria. It is also important to mention that low silver-doped bioglass nanoparticles (Ag2O ≤ 1.5 mol%) could be a required multifunctional candidate in bone tissue engineering.

The examination of graphitic carbon nitride (GCN) synthesis and its catalytic activity in hydrogen production from potassium formate was done as a function of the precursor selection. Four different precursors were assessed, namely urea, dicyandiamide, melamine and thiourea. The catalytic activity of the catalysts fabricated from different GCN precursors and palladium (Pd) was compared. The catalyst prepared from dicyandiamide, Pd-GCN(D), was found to be the most active of the four precursors tested during the first reaction cycle. Nonetheless, the catalyst prepared from urea, Pd-GCN(U), has been attributed by us as the preferred catalyst due to its excellent catalytic activity as well as its phenomenal stability over multiple cycles, which was not observed for the other three catalysts. The better catalytic activity of Pd-GCN(U) is correlated to the high surface area and pore volume of the material. Both the GCN and Pd-GCN samples were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, powder X-ray diffraction, Brunauer-Emmett-Teller methods, scanning tunneling electron microscopy, and X-ray photoelectron spectroscopy.