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This study is aimed at characterizing the thermal stability and evaluating the conversion of Arthrospira platensis ( Spirulina platensis ), a species of microalgae, to various chemicals and intermediates via non-catalytic and catalytic fast pyrolysis using different zeolites. Thermogravimetric analysis was performed to evaluate the kinetics of decomposition of the algae using integral isoconversional method of Vyazovkin, and fast pyrolysis experiments were performed in a micropyrolyzer and the relative composition of the pyrolysates was analyzed in a gas chromatograph/mass spectrometer. The effects of (i) temperature during non-catalytic fast pyrolysis, and (ii) zeolite type, zeolite:algae mass ratio and temperature during catalytic fast pyrolysis on pyrolysate composition were analyzed. The formation of long chain organics like alkanes, alkenes, carboxylic acids and nitriles decreased, while that of CO 2 increased with increase in pyrolysis temperature from 350 to 800 °C. The addition of ZSM5, zeolite-β and zeolite-Y catalysts at 10:1 wt./wt. loading to algae at 600 °C significantly altered the product spectrum involving the formation of nitriles, aromatics, and cycloalkanes. Acetonitrile, benzene, toluene, xylene, cyclobutane and dimethyl cyclopropane were the major organics. Calorific value of the organic components in the pyrolysate (>30 MJ kg −1 ) was significantly higher than that of the raw algae (20.75 MJ kg −1 ). Increase in catalyst loading (from 2:1 to 50:1 wt./wt.) and temperature (from 350 to 600 °C) resulted in significant increase in production of monoaromatics, polyaromatics and cycloalkanes, whereas the formation of nitriles increased and decreased with catalyst loading and temperature, respectively. Plausible reactions leading to the observed product distribution are discussed. This study shows that useful organic intermediates can be obtained via catalytic fast pyrolysis of spirulina. [ABSTRACT FROM AUTHOR]

Aged automobile engine oils contain highly oxidized and hazardous organic compounds, and their disposal adversely affects the environment, underground, and surface waters. Therefore, it is imperative to develop innovative strategies to solve the problem of disposal of waste engine oils. One way is to recover value added chemicals and intermediates from it. This study focuses on recovery of useful hydrocarbons from highly oxidized, waste motorbike engine oils via catalytic fast pyrolysis using zeolites belonging to ZSM-5, Zeolite-β and Zeolite-Y (ZY) families. Pyrolysis experiments were conducted in a micropyrolyzer connected to a gas chromatograph–mass spectrometer. Initially, non-catalytic fast pyrolysis was performed at temperatures from 300 to 800 °C, and it was found that high temperatures led to the formation of C 3-10 alkenes, while low temperatures resulted in high yields of heavy fractions like C 31-60 alkanes and oxidized aromatics. In order to selectively improve the production of C 6-15 alkanes that are valuable as fuel molecules, catalytic fast pyrolysis was performed at 400 °C using 1:1 wt./wt. of oil:zeolites. Hydrogen form of ZY resulted in c.a. 65% of C 6-15 linear, branched, and cyclic alkanes, while other catalysts promoted the formation of alkenes. The yields of C 6-15 linear and cyclic alkanes increased with micropore area, pore volume, and surface acidity of the zeolites. An increase in catalyst quantity significantly increased the yield of C 6-10 alkanes, while reducing the C 11-15 alkane yield and promoting the formation of C 3-5 alkanes. High temperatures led to a significant drop in the production of linear and branched alkanes, but promoted the formation of alkenes and cyclic hydrocarbons. This work has demonstrated that catalytic fast pyrolysis using zeolites is a potential technique to selectively recover value added hydrocarbons from highly oxidized engine oils. [ABSTRACT FROM AUTHOR]

It is important to devise new strategies to derive value from lignin, which is a potential waste by-product from paper industries and present day biorefineries. In this research, we report, for the first time, a facile preparation and characterization of a range of chitosan-alkali lignin composites for the removal of harmful effluents present in wastewater. The composites were characterized by the presence of weak bonding between β-1,4-glycosidic linkage, amide and hydroxyl groups of chitosan, and ether and hydroxyl groups of alkali lignin. Various reaction parameters like chitosan content in the composite, initial pH and adsorbent dosage were optimized. Batch adsorption studies showed that chitosan-alkali lignin (50:50) composite exhibited maximum percentage removal of anthraquinonic dye, Remazol Brilliant Blue R (RBBR), and Cr(VI) compared to other composites, chitosan and alkali lignin. Adsorption of RBBR on the composite followed Langmuir isotherm, and the adsorption of both RBBR and Cr(VI) followed pseudo second order kinetics. A mechanism of adsorption that involves (i) electrostatic interaction of protonated amino and hydroxyl groups of the composite with anionic SO3- and HCrO4- groups of dye and Cr(VI), respectively, and (ii) chemical interaction between amino and hydroxyl groups of the composite, and carbonyl moiety of the dye, was proposed. [ABSTRACT FROM AUTHOR]

Employing endothermic hydrocarbon fuels in high speed flights aids in regenerative cooling of the aircraft surfaces and components due to the physical and chemical heat sink mechanisms they offer. The development of such fuels involves a thorough understanding of its pyrolysis characteristics in the presence of additives. In this study, analytical Curie point pyrolyzer is used to conduct pyrolysis of Jet-A1 fuel, and investigate the effect of temperature and free radical initiators on the pyrolysate composition. The temperatures were 590 °C, 740 °C and 920 °C, and the initiators were triethylamine (TEA), 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), phenyl hydrazine (PH), 1-nitropropane (NP), di-tert-butyl peroxide (DTBP), and cumene hydroperoxide (CH). The results showed that, at 590 °C, the addition of TEMPO, NP and PH, all at 5 wt% to the fuel, improved the cracking reactions with 25% decline in yield of alkanes compared to pyrolysis of neat Jet-A1. It was also observed that the yield of alkyl-substituted benzenes was high in presence of TEMPO and PH, while the yield of iso-alkanes was high in the presence of DTBP, CH and TEA. At 920 °C, the yield of low molecular weight alkenes (C3-C7) was high with TEMPO (11.6%) followed by PH (6.8 wt%), TEA (6.7 wt%) and NP (6.5 wt%). The plausible reactions occurring in the presence of initiators are discussed by thoroughly analyzing the pyrolysates. [Display omitted] • Low molecular weight (C3-C7) alkenes were produced at 920 °C using initiators. • Light alkenes yield: TEMPO (11.6%) > Phenyl hydrazine, Triethyl amine, Nitropropane (6.5–6.8%). • Alkyl benzenes production was high using TEMPO, phenyl hydrazine, triethyl amine and nitropropane. • With cumene hydroperoxide and di-tert-butyl peroxide, high isoalkanes were produced. [ABSTRACT FROM AUTHOR]

As an object is passing through a static scattering medium, a speckle is formed. We can reconstruct the image from the speckle, based on the principle of optical memory effect. However, when the object passes through a dynamic scattering medium, such as fog, the reconstructed image quality will be degraded even blurred. In this paper, we want to investigate the reconstructed image as the object passes through the dynamic scattering medium, which is simulated by a rotating ground glass. We focus on studying the influence of both the acquisition time of the CCD and the angular velocity of the rotating ground glass on the fidelity of the reconstructed image. The experimental results show that appropriately reducing the acquisition time of the CCD is beneficial to reconstruct image from the single speckle in the dynamic scattering imaging. The proposed results may have applications in imaging through fog and biological tissues. [ABSTRACT FROM AUTHOR]

• Detailed study on analytical fast pyrolysis of washed and unwashed empty fruit bunch. • Apparent activation energy of fast pyrolysis was 30–39 kJ/mol. • High selectivity to long chain carboxylic acids (37%) in Py-GC/MS pyrolysates at 700 °C. • High selectivity to phenolic compounds (74%) in bio-crude from microwave pyrolysis. • Higher heating value of bio-crude from microwave pyrolysis was 30 MJ/kg. This study is focused on kinetics and product distribution from untreated empty oil palm fruit bunch (EOPFB) biomass and treated EOPFB using analytical pyrolysis combined with gas chromatograph/mass spectrometer and Fourier transform infrared spectrometer, and microwave pyrolysis. Industrial water wash led to significant reduction in ash content of EOPFB from 5.9 wt% to 0.7 wt%. Isothermal mass loss data collected in the temperature range of 400–700 °C showed that fast pyrolysis in the Pyroprobe® reactor followed diffusion-controlled kinetics with apparent activation energies of 30.4 and 39.6 kJ mol−1 for untreated and treated EOPFB, respectively. Analytical pyrolysis of untreated EOPFB resulted in high selectivity to fatty acids, while phenolics dominated the pyrolysates from treated EOPFB. The selectivities to phenolic compounds were 74% and 57% from treated and untreated EOPFB, respectively, via microwave pyrolysis. The higher heating values of bio-crude from microwave pyrolysis of untreated and treated EOPFB were 30.1 and 29.7 MJ kg−1, respectively. [ABSTRACT FROM AUTHOR]

While oleaginous yeasts have been extensively investigated for single-cell oil production, less attention has been paid towards valorization of the erstwhile-discarded de-oiled biomass. The current study demonstrates the valorization potential of the de-oiled biomass through production of bio-crude by hydrothermal liquefaction process. The performance of the process was enhanced by using glycerol as co-solvent and also by optimizing the processing conditions. Glycerol addition enhanced the bio-crude yield up to 50 wt% with an improved energy content of 32 MJ/kg. The major organic groups found in the bio-crude are acids, esters and phenolics. Typical energy recovery achieved in bio-crude was in the range of 43–62%. Thus, strategic valorization of yeast into green crude with net energy gain, as evident from the energy balance, implies the process is energetically favourable. Image 1 • De-oiled yeast biomass was successfully used as a feedstock for HTL. • Glycerol, used as a co-solvent for HTL, improved the bio-crude yield. • HTL process parameters were optimized. • Characterization of bio-crude and bio-char were performed. • Mass and energy balance of HTL implied a net energy gain. [ABSTRACT FROM AUTHOR]

Highlights • PMMA pyrolysis kinetics was studied in the broad temperature range of 315÷500 °C. • The kinetic data were obtained using first order model and iso-conversion method. • The kinetic data validity was verified by modeling reaction rate versus temperature. • The kinetic parameters may be used in numerical simulation of PMMA combustion. Abstract Using the methods of differential mass-spectrometric thermal analysis (DMSTA), thermogravimetric analysis (TGA), microscale combustion calorimetry (MCC), and fast pyrolysis (FP), thermal decomposition of high-molecular-weight polymethylmetacrylate (PMMA) has been investigated in the temperature range of 315÷500 °C. Based on these data, the kinetic parameters (the activation energy, the pre-exponential factor) were obtained of a one-step pyrolysis reaction in supposition of a first-order reaction using simple mathematical fitting and an iso-conversion method. Validity of the obtained kinetic parameters was verified by comparing the experimental data on dependence of the decomposition rate on temperature in the broad range of the heating rates with the results of simulating the above dependence, using these kinetic parameters. These parameters, obtained in the broad temperature range, may be further used in numerical simulation of PMMA combustion under fire conditions and for assessing the polymer's flammability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Microwave pyrolysis of lignin performed with activated carbon, charcoal and graphite. • High yield and selectivity of simple phenols over guaiacols and syringols. • Maximum bio-oil yield of 66 wt% obtained with 10 g:90 g lignin:activated carbon. • Maximum selectivity of 79% for phenol and 34% for cresol achieved in bio-oil. • Effects of bound moisture in the susceptor on heating rate and product distribution elucidated. Abstract With an objective to improve the yield and selectivity of phenols in pyrolysis bio-oil from lignin, this study investigates the effects of mass ratio of lignin-to-susceptor and different types of susceptors (activated carbons of different particle sizes, charcoal and graphite) in microwave pyrolysis. Pyrolysis was carried out in a batch microwave reactor, and the temperature profiles at different operating conditions were captured. Increasing the mass of susceptor with respect to lignin enhanced the bio-oil yield, and maximum yield of 66 wt% with >90% selectivity to phenols was obtained with 10 g lignin:90 g activated carbon. Moisture present in the susceptor is shown to control the pyrolysis severity and lead to better phenol yields. This was verified by the high yield of hydrogen gas formed due to the steam-assisted cracking of lignin. With highly porous activated carbon, 80% selectivity of phenol was obtained, albeit with a low yield of bio-oil. [ABSTRACT FROM AUTHOR]

• Soild "rich-hydrogen" donors act as "hydrogen sources" for coal pyrolysis. • Existing detection methods of free radicals indirectly reflect their properties. • Free radical behaviors signally affect the yield and quality of pyrolysis products. • Pyrolysis temperature is the most key influence factors of free radical behaviors. • Effects of free radical behaviors on coke/semi-coke and tar are more attention. Low-cost and accessible "hydrogen source" are the key to reducing the cost of coal hydropyrolysis technology. The mechanism of hydrogen supply is a crucial scientific issue in this technology. Solid "hydrogen-rich" donors, such as biomass, waste plastics, oil shale, and coal liquefaction residue, possess favorable characteristics such as affordability, abundant availability, high volatility and a high H/C ratio, which are considered ideal solid "hydrogen sources" for coal hydropyrolysis. The co-pyrolysis reactions between low-rank coal and solid "hydrogen donor" follow the mechanism of free radical reactions. Moreover, a clear investigation of the free-radical behaviors and synergistic interactions between them can clarify the hydrogen supply mechanism in the co-pyrolysis process of solid "hydrogen-rich" donors, resulting in the controlled production of high-quality oil and gas products. This review systematically summarizes the free-radical behaviors during the co-pyrolysis of low-rank coal and solid "hydrogen-rich" donors: Three detection methods of free radicals and their applications are first introduced. Then, the factors influencing the free-radical behaviors during the co-pyrolysis are discussed, and the influences of the free-radical behaviors on the products obtained by the co-pyrolysis are analyzed. Finally, the results and challenges of free-radical behaviors are outlined. This work is intended to provide a comprehensive and scientific basis for completing the mechanism of free-radical reactions in the co-pyrolysis of low-rank coal and solid "hydrogen-rich" donors. [ABSTRACT FROM AUTHOR]

The majority of ocean plastic wastes supposedly comes from land-based sources, while the remaining comes from marine-based activities and sources such as lines, fishing nets, abandoned vessels and ropes. In this study, plastic wastes were collected from the sea shore in Chennai, India, and thoroughly characterized to determine their composition and plastic types. Eight out of nineteen samples were polyethylenes (PE), and their thermal stability, functional group and elemental composition were assessed using different techniques. Analytical pyrolysis hyphenated with gas chromatograph/mass spectrometry (Py-GC/MS) was performed to identify impurities and quantify the volatile hydrocarbons. Thermal desorption indicated the presence of fatty acids and plasticizers such as dimethyl and diethyl phthalates in most of the samples. The PE samples varied significantly in terms of their typical decomposition products, and the overall selectivities to alkenes, alkanes and alkadienes were in the range of 44.79–53.15%, 21.77–29.0% and 17.56–22.56%, respectively. The major products, alkenes, were distributed in the carbon number range of C 5 -C 20. Upto 16 wt% of the hydrocarbons in the pyrolysate from various samples were quantified based on carbon number range. [Display omitted] • The beach plastics include polyethylene, polypropylene, polyurethane, polyvinyl chloride, polystyrene and polyester. • Polyethylenes of 8 different varieties were found in the plastic waste mixture. • Fatty acids, phthalate and non-phthalate plasticizers were identified in the wastes. • The selectivities to alkenes, alkane and alkadienes were 45–53%, 22–29% and 18–23%, respectively. • The quantified yields of alkenes, alkanes and alkadienes were comparable with literature. [ABSTRACT FROM AUTHOR]

In this study, Titania (TiO 2 ) based composites reinforced with 2 wt% of various carbon nanomaterials were prepared using spark plasma sintering (SPS). Prior to SPS, the samples were ball milled. The reinforcements used in the composites were graphene nanoplatelets (GNP), carbon nanotubes (CNT) and single walled carbon nanohorns (SWNH). The ball milled powders and SPS compacts were characterized using various techniques. Mechanical and photocatalytic properties of the SPS composites were evaluated and compared for different nano-carbon reinforced TiO 2 composites. X-ray diffraction and Raman spectroscopy studies confirmed that the milled powders comprised of Anatase phase which transformed into Rutile phase during SPS. Nano transformation twins were observed in Rutile grains. Fractured surfaces showed that the reinforcements were well bonded with the TiO 2 grains and the SWNH reinforcement resulted in comparatively finer grain size. Nanoindentation studies showed that the hardness and elastic modulus of GNP reinforced composites was 78% and 30% respectively higher compared to TiO 2 matrix. The hardness and modulus of the CNT reinforced TiO 2 increased by 22% and 5.4% respectively while that of the SWNH reinforced TiO 2 increased by 11% and 23% respectively. GNP and CNT reinforced TiO 2 exhibited superior photocatalytic activity for the degradation of methylene blue dye compared to pure TiO 2 . [ABSTRACT FROM AUTHOR]

The present investigation employed transposon technology to enhance the degradation of recalcitrant petroleum hydrocarbons present in petroleum oil sludge by using biosurfactant hyper-producing strain Enterobacter xiangfangensis STP-3. Out of 2500 transposon induced mutants, mutants M 257 E.xiangfangensis and M 916 E.xiangfangensis hyper-produce biocatalytic lipoprotein biosurfactant by1.98 and 2.34 fold higher than wild-type strain. Transposon induced mutation also modified the amino acid composition which improved the hydrophobicity and thermal stability of the biosurfactants produced by mutants, compared to the wild-type biosurfactant. GC-MS and LC-MS-MS revealed that biosurfactants have pentameric lipid moiety and esterase as protein moiety. Increased biosurfactant hydrophobicity and yield by the mutants resulted in the enhanced bioavailability of petroleum hydrocarbons, thereby mutants M 257 E.xiangfangensis and M 916 E.xiangfangensis demonstrated better petroleum oil sludge degradation by 82% and 88% respectively, than wild-type (72%). Disrupted genes vgr G and pgm M in M257 E.xiangfangensis and M916 E.xiangfangensis respectively hyper-produce biosurfactant by competitive pathway inhibition and increased precursor availability mechanism. Hyper-production of biosurfactant was also validated by comparing the expression of biosynthetic genes ent E , ent F and est using qPCR. This is the first report on the application of transposon technology to hyper-produce biosurfactant for the effective bioremediation of hydrocarbon contaminated environments. [Display omitted] • A novel biocatalyst conjugated bioamphiphile is used for the treatment of oil sludge. • Transposon technology employed to improve the strain to overproduce bioamphiphile. • Improved strain produced highly efficient bioamphiphile with two-fold yield. • Mechanism behind the production of novel bio-amphiphile was hypothesised. • Achieved effective PHCs treatment with the intervention of novel amphiphile. [ABSTRACT FROM AUTHOR]

[Display omitted] • Milli-Q water, tap water, sea water, industrial waste water and recycled water were used. • High organic content in water enhanced the bio-crude yield up to 36.4 wt%. • Salt content in the water enhanced the yield and quality of hydrochar. • Salt content in the water reduced the total organic carbon in the aqueous phase. • K+, PO 4 3- and NH 4 + ions accumulated in the aqueous phase from rice straw. The need for fresh water limits the application and scale-up of hydrothermal technologies to convert waste biomass to energy and chemicals. In an effort to demonstrate the use of wastewater for sustainable process development, this work is focused on hydrothermal liquefaction (HTL) (350 °C, 18 MPa, 30 min) and carbonization (HTC) (200 °C, 7 MPa, 4 h) of rice straw with water from various sources (milli-Q water, tap water, seawater, recycled wastewater and industrial wastewater). The bio-crude yield from HTL was maximum (36.4 wt%) with industrial wastewater, while the yield of hydrochar from HTC was maximum (74.5 wt%) with seawater. The ions like K+, PO 4 3- and NH 4 + accumulated in the aqueous phase from rice straw. The hydrochars from HTL experiments contained significantly higher amount of ash compared to that from HTC experiments. Cyclopentenones and phenols were the major constituents of the bio-crude, whose HHV was 26.3 MJ/kg using seawater. [ABSTRACT FROM AUTHOR]

Schematic 1 BBAs-assisted microwave pyrolysis of coal. [Display omitted] • Three BBAs used in microwave pyrolysis of coal were successfully prepared. • Microwave absorbency of BBAs was decided by special structure and active component. • Excellent electromagnetic and catalytic property of BBA-BM due to cluster structure. • Microwave pyrolysis reactions of coal with adding BBAs were obviously enhanced. • "Hot-spots" effect and "rim-edge" effect might improve the H free radical. Microwave pyrolysis technology is a promising thermal processing technology of coal, but its absorbents do not get enough attention. In this study, waste bluecoke powder, used as a carbon matrix, and Fe compound, used as an active component, were employed to prepare three bluecoke-based absorbents (BBAs). Three methods were employed to prepare BBAs, viz., ultrasonic immersing (UI), ball milling (BM), and hydrothermal synthesis (HS). The structure, morphology, electromagnetic property, catalytic property and potential synergism induced by the BBAs on microwave pyrolysis were analyzed and discussed using different analytical techniques. The results showed that various morphologies and particle sizes of BBAs were obtained due to different preparation methods, and BBA-BM and BBA-HS presented the cluster and wrapped structures, respectively. The effect of bluecoke matrix on microwave absorbency of BBA was little, and this was mainly decided by the special structures and the active component. The permittivity loss and permeability loss factor of BBA-BM at 2.45 GHz were maximum at 0.2974 and 0.5263, respectively, which showed that the electromagnetic property of BBA-BM was the best. The yields of tar and coal gas were improved on adding BBA, and the quality of tar was also improved, especially with BBA-BM. The "hot-spot" effect and "rim-edge" effect of BBAs might promote the generation and activation of hydrogen free radicals, resulting in enhanced microwave pyrolysis of coal. [ABSTRACT FROM AUTHOR]

[Display omitted] • Use of alkali catalyst produced 62% deoxygenation in bio-crude from Kappaphycus alvarezii. • 99% energy recovery was observed in bio-crude and biochar from Eucheuma denticulatum. • Catalytic treatment resulted in high bio-crude yield (∼16 wt%) from both macroalgae. • High selectivity to cyclic oxygenates (84%) was observed in the bio-crude with K 2 CO 3. • The use of catalysts enhanced the release of sulphates, chlorides, and cations like Na+, K+. Hydrothermal liquefaction of red macroalgae species, Kappaphycus alvarezii (KA) and Eucheuma denticulatum (ED), was performed at 350 °C in the presence of 5 wt% neutral and alkali catalysts like Na 2 CO 3 , K 2 CO 3 , CaCO 3 , Na 2 SO 4 , NaOH, and KOH. The maximum bio-crude yield of 26.7 wt% and 18.5 wt%, on a dry ash-free basis, was obtained from Na 2 CO 3 treatment of KA and KOH treatment of ED, respectively. The bio-crude from both feedstocks mainly consisted of cyclic oxygenates, whose selectivities were maximum in K 2 CO 3 and CaCO 3 treatments. The calorific value of the bio-crude was 38.5 MJ/kg from KA and 30.8 MJ/kg from ED, while that of biochars was 20–24 MJ/kg. A high degree of deoxygenation (64.2%) was observed in bio-crude produced from Na 2 SO 4 treatment of KA biomass. Salts of Cl–, SO 4 2– and K+ constituted the major inorganic portion of the aqueous phase. Maximum energy recovery (99%) was observed from the Na 2 CO 3 treatment of ED. [ABSTRACT FROM AUTHOR]

[Display omitted] • High selectivity to C9 alkyl guaiacols (51%) was obtained using Pd-Al 2 O 3 /activated biochar. • Pd0 catalyzes hydrogenation of C α =C β and Al catalyzes dehydroxylation of C γ −OH. • 4-Propyl guaiacol was obtained at 38% selectivity at 240 °C, 3 MPa H 2 , and 3 h. • Coniferyl alcohol was used as a model compound to probe surface reaction chemistry. • Propyl guaiacol formation mechanism is elucidated using DFT calculations. The conversion of biomass-derived lignin to valuable monomeric phenols at high selectivity is of paramount importance for sustainable biorefineries. In this study, a novel Pd-Al 2 O 3 supported on activated biochar catalyst is developed for lignin hydrogenolysis. The catalyst characterization revealed that the (1 1 1) planes of both of Pd0 and Al 2 O 3 were exposed to the surface. The maximum lignin conversion of 70.4% along with high liquid yield (∼57 wt%) was obtained at 240 °C, 3 h and 3 MPa H 2 pressure. The total monomeric phenols yield in the liquid was 51.6 wt%, out of which C9 monomeric guaiacols constituted ∼ 30.0 wt% with 38.0% selectivity to 4-propyl guaiacol. Using the reaction intermediate, coniferyl alcohol, chemoselective hydrogenation of C α =C β is proved to occur over the Pd site, while dehydroxylation of C γ –OH is shown to occur over the alumina site. An impressive carbon atom economy of 60% was achieved for the production of monomeric phenols. [ABSTRACT FROM AUTHOR]

[Display omitted] • High lignin conversion (67–69%) was achieved with Pd-metal oxide catalysts. • Pd-Mo/biochar promoted high selectivity (57%) to C9 monomers at 240 °C, 3 h. • The total monomer yield was high (42 wt%) with Pd-Mo/biochar with low amount of heavies. • Catalytic activity to form 4-propyl guaiacol is in line with electropositivity of metal oxides. Valorizing lignin to phenolic monomers and fine chemicals is an essential component of a sustainable biorefinery that uses lignocellulosic feedstocks. In this study, Pd-metal oxides (ZrO 2 , WO x , MoO 3) supported on activated biochar (ABC) catalysts were developed for hydrogenolysis of lignin. The metals (2% Pd, 5% Zr, 5% W, 5% Mo) were supported on activated biochar using the wetness impregnation method, and the catalysts were extensively characterized. The effect of addition of secondary metals on active surface properties such as acidity, Pd metal particle size and dispersion were also evaluated. The selectivity to C9 monomeric phenols followed the trend: 2Pd-5Mo/ABC (57.3%) > 2Pd-5Zr/ABC (49.2%) > 2Pd-5W/ABC (45%) > 2Pd/ABC (42.9%). The maximum C9 phenolic monomer yield achieved in this study was ~ 22 wt%. The fractional conversion of lignin was 67–69% with Pd-metal oxide catalysts. The presence of Mo in the catalyst inhibited the hydrogenation of aliphatic C α = C β in lignin and led to the formation of t -isoeugenol, while the presence of W and Zr resulted in selective formation of the hydrogenated product, propyl guaiacol. Using model compounds, it is proved that the formation of propyl guaiacol is via hydrogenation of t -isoeugenol, and not through dehydroxylation of propanol guaiacol. The dehydroxylation activity of the catalysts is attributed to the higher Lewis acidity and electropositive nature of the metals. A notable carbon atom economy of 47–50% towards total phenolic monomers was achieved with 2Pd/ABC, 2Pd-5Mo/ABC and 2Pd-5Zr/ABC catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recycled aqueous phase decreases the bio-crude yield and favors bio-char formation. • Quality of bio-crude and bio-char is improved with recycle. • Bio-char from rice straw exhibits good soil amendment characteristics. • Levulinic acid and its derivatives are the major compounds in the aqueous phase. • Accumulation of chloride ions in the aqueous phase hinders bio-crude formation. Aqueous phase (AP) recirculation is a promising process intensification strategy to improve the yield and quality of the products and cost efficiency of the hydrothermal liquefaction (HTL) process by replacing the fresh water used in the experiments. The results demonstrate that AP recirculation in the HTL of rice straw decreases the bio-crude yield from 32.6 wt% to 9.1 wt% after the third recycle, while enhancing the bio-char yield up to 64.1 wt%. The bio-crude and bio-char show improved carbon and hydrogen content with AP recirculation. The decrease in selectivity to aliphatic hydrocarbons in the bio-crude and bio-char, coupled with increase in H 2 content in the gaseous phase, suggests the prevalence of dehydrogenation reactions. The bio-char achieved better thermal stability, water retention and cation exchange capacity with AP recirculation. There was a significant accumulation of K+, Ca2+ and Cl– with a concomitant decrease in silicates, sulfate and phosphate in the AP. [ABSTRACT FROM AUTHOR]

[Display omitted] • Impact of temperature, residence time and solvents on liquefaction of MSW was studied. • Maximum bio-crude yield (58 wt%) was obtained at 350 °C, 30 min using glycerol. • The bio-crude had C, H and HHV of 77 wt%, 6.8 wt% and 35.6 MJ/kg, respectively. • Deoxygenation achieved in the bio-crude was ~50% with energy recovery of 95%. • Phenols and cyclo -oxygenates were the major products in bio-crude. This study is focused on the valorization of heterogeneous municipal solid waste collected from the landfill using hydrothermal liquefaction process using glycerol as a co-solvent. The effects of temperature (300–350 °C) and residence time (15–45 min) on the yields and quality of the product fractions were investigated at 8 wt% solid loading. The yield of bio-crude significantly increased from 15.2 wt% with water as the solvent, to 58 wt% with water-glycerol (1:1 v/v) as the solvent possessing an energy content of 35.6 MJ/kg at 350 °C, 30 min. The quality of the bio-crude obtained using glycerol was comparable to that using tetralin as a hydrogen donor co-solvent. Phenolic compounds and cyclooxygenates were the major compounds in the bio-crude, and aliphatic hydrocarbons increased with residence time. Maximum energy recovery of 95% was achieved in the products with an energy consumption ratio of 0.43 for the bio-crude signifying the energetic feasibility of the process. [ABSTRACT FROM AUTHOR]

• Kinetics of PMMA decomposition is slowed down by the addition of 5 wt.% Exolit®. • Distributed activation energy model was developed to describe slow pyrolysis kinetics. • The addition of Exolit® delayed the time evolution of methylmethacrylate from PMMA. • The yield of methylmethacrylate from fast pyrolysis decreased by 10−20 wt.% with Exolit® addition. • Contracting cylinder and Avrami-Erofeev models describe the fast pyrolysis kinetics. In this study, thermal decomposition kinetics of poly(methylmethacrylate) (PMMA) is investigated in the presence of a phosphorus-based flame retardant (Exolit®) under slow and fast pyrolysis conditions. Multi-Gaussian distributed activation energy model (DAEM) is employed to determine the kinetic parameters at slow heating rates. The multi-Gaussian DAEM with five parallel independent reactions predicts well the experimental mass loss and differential mass loss profiles. The incorporation of 3 and 5 wt.% Exolit® in PMMA delays the decomposition temperature and slows down the rate of PMMA pyrolysis. Isothermal fast pyrolysis is carried out in the temperature range of 400−700 °C at short time intervals of 2−150 s. The rate constant of decomposition of PMMA + 5 wt.% Exolit® mixture was lower than that for pure PMMA. Through analytical pyrolysis coupled with Fourier transform infrared spectroscopy it is shown that the addition of Exolit® to PMMA significantly delays the evolution of methylmethacrylate, which is the major pyrolysate. [ABSTRACT FROM AUTHOR]

• Coking coals were free of liptinite, while non-coking coal was rich in liptinite maceral. • Naphthalene derivatives and polyaromatics were high in tar from microwave pyrolysis. • Monoaromatics were the major compounds from analytical pyrolysis at different heating rates. • Char yields from microwave and analytical pyrolysis were similar for all coals. • Core of the pellet was highly carbonized than its surface in microwave pyrolysis. Pyrolysis conditions and mechanism greatly influence the quality of tar and char from coal, which eventually determine their further usage. This work investigates the pyrolysis of three coking coals and a non-coking high ash Indian coal via microwave-assisted and conventional heating, and the influence of heating rate, coal type, and heating mechanism on product yields and tar composition. Microwave pyrolysis experiments were conducted in a home-built microwave reactor, and analytical pyrolysis experiments were conducted in a Pyroprobe® interfaced with gas chromatograph-mass spectrometer (Py-GC/MS). The tar yields from microwave pyrolysis of coking coals were similar (∼7 wt.%), while it was slightly high from high ash Indian coal (∼11 wt.%). Char yields from both microwave and analytical pyrolysis were similar (78 ± 1.5 wt.%). Microwave pyrolysis tars were rich in naphthalene derivatives and polyaromatics with more than 45% selectivity, while analytical pyrolysis tar was rich in monoaromatics (>30%). There was no significant variation in the selectivities of other organic fractions. High selectivity of polyaromatics in microwave pyrolysis tar is due to the generation of localized hotspots, which led to excessive cracking of primary pyrolysis vapors. The higher heating value (HHV) of microwave pyrolysis tar was 32–33 MJ kg−1, while that of analytical pyrolysis tar was higher (35–36 MJ kg−1), which is attributed to the presence of more monoaromatics in the latter. Hydrogen and methane were the major components in the gaseous fraction. Coal chars were characterized using different techniques, and they were rich in carbon (≈80 wt.%) with high energy content (29 MJ kg−1). [ABSTRACT FROM AUTHOR]

Ghost holography has attracted notable applied interest in the modern quantitative imaging applications with the futuristic features of complex field recovery in the diversified imaging scenarios. However, the utilization of digital holography in ghost frame works introduces space bandwidth or time bandwidth restrictions in the implementation of the technique in applied domains. Here, we propose and demonstrate a quantitative ghost phase imaging approach with holographic ghost diffraction scheme in combination with the phase-shifting technique. The approach makes use of an off-axis holography system by superposing the ghost diffraction fields with a reference random field generated from an independent diffuser. In addition, the technique utilizes the high-speed response of a spatial light modulator to introduce a fast temporal phase shifting to one of the ghost-diffraction fields that views the object, which practically results in the enhancement of the effective bandwidth in the frequency domain by suppressing redundant terms. The applicability of the technique is experimentally validated by demonstrating the quantitative phase imaging of various abrupt and continuous phase samples.

The current investigation focuses on the copyrolysis of Mesua ferrea L. (a nonedible oilseed, also known as Nahar) and polyethyelene terephthalate (PET) plastic waste to gain insights into the composition of pyrolysates and the thermal decomposition of complex and mixed feedstocks. The physicochemical properties of the feedstocks were studied through thermogravimetric analysis at a heating rate of 15 °C min -1 , bomb calorimetry, and proximate/ultimate analysis. The proximate analysis revealed that both biomass and PET had relatively low moisture contents (3.33 and 0.61%, respectively) and high volatile matter (88% for biomass and 94.53% for PET). The pyrolysate composition studies using analytical pyrolysis coupled with a gas chromatograph/mass spectrometer revealed significant generation of fatty acids (∼79%) from Nahar and benzoic acid (24%) and acetylbenzoic acid (15.5%) from PET at 590 °C. The analytical pyrolysis of feedstock mixtures at biomass:PET (B:P) of 1:1, 2:1, and 1:2 w/w revealed the dominance of both aliphatic and carboxylic acids. Further, fixed-bed copyrolysis experiments were performed using Nahar, PET, and its mixtures in a temperature range of 550-650 °C at 15 °C min -1 heating rate. The optimal temperature of 600 °C was chosen for both biomass and copyrolysis (2:1 feed ratio) due to the high yield of pyrolytic liquid (27 wt % for biomass alone; 35 wt % for copyrolysis). The produced bio-oil was thoroughly characterized, and it was found that fatty acids and carboxylic acids such as n -hexadecanoic acid, octadecenoic acid, octadecanoic acid, and benzoic acid were found in a significant proportion. The mechanism of copyrolysis vapors was studied by analyzing the pyrolysates obtained at different operating conditions. Decarboxylation and decarbonylation fatty acid species were found to be typical pathways for the formation of hydrocrabons like hexadecane, pentadecane, heptadecane, and heptadecene., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

In order to obtain extended storage life of food-grade materials and better barrier properties against environmental factors, a multilayer plastic packaging (MLP) is often used. The multilayer packaging plastics are labelled as "other" (SPI#7) category, and are manufactured with a combination of barrier plastics, rigid plastics and printing surface. Owing to their complex composition and difficulty in separating the layers of MLP, its mechanical recycling is challenging. In this study, MLP wastes (MLPWs) were collected from zero-waste garbage collection center of IIT Madras, India, and thoroughly characterized to determine their composition and plastic types. MLPWs were characterized using various physico-chemical methods such as thermogravimetric/differential scanning calorimetric analysis, Fourier transform infrared spectroscopy, bomb calorimetry, and proximate and ultimate analyses. The MLPWs were mainly made up of polyethylene (PE) and polyethylene terephthalate (PET). Further, the non-catalytic and zeolite-catalyzed fast pyrolysis of these MLPWs were studied using analytical pyrolysis coupled with gas chromatograph/mass spectrometer (Py-GC/MS). The non-catalytic fast pyrolysis of MLPWs primarily produced a mixture of aliphatic and alicyclic hydrocarbons, while zeolite catalyzed fast pyrolysis resulted in the formation of mono-aromatic hydrocarbons (MAHs). The activity of HZSM-5, zeolite Y (HY) and zeolite beta (Hβ) catalysts were evaluated, and the salient products were quantified. The yields of MAHs like benzene, toluene, ethylbenzene and xylene using the zeolites followed the trend: HZSM-5 (14.9 wt%) > HY (8.1 wt%) > Hβ (7.8 wt%), at 650 °C. The use of HZSM-5 resulted in highest yield of MAHs, viz. 16.1 wt%, at the optimum temperature of 550 °C and MLPW-to-catalyst ratio of 1:15 (w/w). The superior activity of HZSM-5 is due to its nominal acidity and larger pore size of 4.24 nm, as compared to HY and Hβ. The MAHs yield from three other types of MLPWs varied in the range of 9-16 wt%. The present study demonstrates a promising pathway for the catalytic upcycling of highly heterogeneous MLPWs in the context of circular economy., Competing Interests: Declaration of competing interest It is declared that the authors have no conflicts of interest or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Computational methods have been established as cornerstones in optical imaging and holography in recent years. Every year, the dependence of optical imaging and holography on computational methods is increasing significantly to the extent that optical methods and components are being completely and efficiently replaced with computational methods at low cost. This roadmap reviews the current scenario in four major areas namely incoherent digital holography, quantitative phase imaging, imaging through scattering layers, and super-resolution imaging. In addition to registering the perspectives of the modern-day architects of the above research areas, the roadmap also reports some of the latest studies on the topic. Computational codes and pseudocodes are presented for computational methods in a plug-and-play fashion for readers to not only read and understand but also practice the latest algorithms with their data. We believe that this roadmap will be a valuable tool for analyzing the current trends in computational methods to predict and prepare the future of computational methods in optical imaging and holography., Supplementary Information: The online version contains supplementary material available at 10.1007/s00340-024-08280-3., Competing Interests: Conflict of interestThe authors declare no competing interests., (© The Author(s) 2024.)

During the COVID-19 pandemic, the world saw an exponential surge in the production of Personal Protective Equipment (PPE) kits, which eventually got discarded in the biomedical waste stream. In this study, thirteen different polymer samples from the PPE kit were collected and characterized using Fourier transform infrared spectrometer, thermogravimetric analysis, and analytical pyrolysis-gas chromatograph/mass spectrometry. The characterization data showed that about 94 % by mass of components were made of only three polymers, viz. polypropylene (PP, 75.6 wt %), polyethylene terephthalate (PET, 12.5 wt %), and polycarbonate (PC, 6 wt %). The analytical pyrolysis of the PPE coverall suit (PP) yielded mainly alkenes containing 2,4-dimethyl-1-heptene as the major compound with 17 wt % yield at 600 °C. The pyrolysates from face shield (PET) were rich in benzoic acid (5.8 wt %) and acetophenone (4.8 wt %), while those from safety goggles (PC) were rich in phenol (17.6 wt %) and p-cresol (12.4 wt %) at 600 °C. HZSM-5 and HY zeolites were used for the catalytic upgradation of pyrolysates especially from PP, PET and PC. The temperature and feed-to-catalyst ratio were optimized by performing catalytic fast pyrolysis experiments at 500 °C, 600 °C and 700 °C with different feed-to-catalyst ratios 1:2, 1:4, and 1:6 (w/w). The yield of aromatic hydrocarbons, viz., BTEX (benzene, toluene, ethylbenzene, xylenes) and naphthalene, was maximum (∼25.7 wt %) from PP coverall when HY catalyst was used at 600 °C and 1:6 (w/w) loading. In the case of PET face shield, the total yield of BTEX, naphthalene and biphenyl was maximum (27.9 wt %) at 600 °C and 1:4 (w/w) of HZSM-5, while in the case of PC goggles, it was maximum (18.6 wt %) at 700 °C and 1:4 (w/w) of HY. This study shows that the entire PPE kit can be valorized via catalytic fast pyrolysis to generate petrochemical products and platform molecules like monoaromatic hydrocarbons at high selectivities., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 Elsevier B.V. All rights reserved.)

Printed circuit boards (PCBs) constitute an important segment of electronic waste that can be effectively utilized to recover valuable metals and organics. The present work is focused on the kinetics and product distribution from pyrolysis of three different PCB samples, viz., television PCB (TV PCB), motherboard PCB (MB PCB), and hard disk PCB (HD PCB). The PCBs were pretreated to eliminate most of the metallic constituents. Kinetic analysis was performed using Vyazovkin's isoconversional method and distributed activation energy model (DAEM). The average apparent activation energies obtained from the Vyazovkin method were 207.2, 158.9, and 179.7 kJ mol -1 for the TV PCB, MB PCB, and HD PCB, respectively. The DAEM with five, four, and four pseudo-components was used to describe the decomposition kinetics of the TV PCB, MB PCB, and HD PCB, respectively. Importantly, two types of distributions, viz., Gaussian and Weibull, were utilized to effectively model the nonisothermal data obtained from thermogravimetric analysis at 10 and 20 °C min -1 . The evolution of pyrolysates belonging to functional groups such as phenolics, aromatics, aliphatics, halogenated compounds, N-containing compounds, and oxygenates was studied at two different temperatures (500 and 700 °C) using analytical pyrolysis-gas chromatograph/mass spectrometry (Py-GC/MS). The Py-GC/MS results demonstrated an increase in selectivity to aromatics and straight-chain aliphatics at 700 °C with a concomitant decrease in selectivity to phenols and oxygenates., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

The present study on one non-edible oilseed (Mesua ferrea L) employs the pyrolysis process to understand the pyrolysate composition and the thermal degradation behavior of biomass. The physicochemical characterization of whole seed was investigated using thermogravimetric analysis at different heating rates (5, 10, 20, and 40 °C min -1 ), bomb calorimeter, proximate/ultimate analysis. FTIR analysis confirmed the presence of the lignocellulosic compounds. Kinetic analysis of biomass was investigated using iso-conversional models such as Friedman, Kissinger-Akhaira-Sunose, Ozawa-Flynn-Wall, Starink, Distributed Activation Energy model, and Avrami model. Further, composition analysis of the pyrolytic vapor was analyzed using analytical fast pyrolysis coupled with gas chromatogram/mass spectrometer (Py-GC/MS) at 400, 500, 600 °C. This study confirmed that alkenes were major pyrolysates, followed by alkanes and esters. The current investigation suggested that Mesua ferrea L whole seed can be converted to valuable chemicals using pyrolysis., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Lignin, a major component of lignocellulosic biomass, is a valuable source of phenolic and aromatic compounds. It is, therefore, vital to develop strategies to selectively deconstruct lignin to valuable chemicals. This study focuses on the kinetics of depolymerization of lignin and the production of phenols via a microwave-assisted catalytic process at mild conditions of 80 °C in dimethyl sulfoxide/water medium. Four different catalysts used in this study, viz., Fe 2 O 3 , LaFeO 3 , ZrO 2 , and zeolite-Y hydrogen (ZYH), were characterized for structure, specific surface area, and surface morphology. The molecular weight reduction of lignin and the evolution of phenolic monomers and oligomers were monitored using various techniques, and the rate constants of lignin degradation in the presence of different catalysts were determined using a continuous distribution kinetics model, assuming scission of the lignin macromolecule at any random position. The rate constants (min -1 ) followed the trend: ZYH (26 × 10 -4 ) ≈ LaFeO 3 (25 × 10 -4 ) > ZrO 2 (22 × 10 -4 ) > Fe 2 O 3 ≈ no catalyst (16 × 10 -4 ). Vanillic acid (15 mg g -1 ) and methyl phenol (17 mg g -1 ) were the major phenolics obtained with LaFeO 3 , whereas coniferaldehyde (13 mg g -1 ) was the major phenolic compound with Fe 2 O 3 . Vanillin was produced at ca. 11 mg g -1 with both Fe 2 O 3 and ZYH. LaFeO 3 is shown to be a promising catalyst for both molecular weight reduction of lignin and the production of monomeric phenols, whereas the use of Fe 2 O 3 results in the formation of only phenols, possibly via specific end-chain depolymerization. The selectivities of the monomeric phenols were higher with these two catalysts, whereas with ZYH and ZrO 2 , the selectivities of the oligomers were better. The reusability of the catalysts and the effect of catalyst loading on kinetics of lignin depolymerization were also evaluated., Competing Interests: The authors declare no competing financial interest.

In this study, mesoporous activated biochar with high surface area and controlled pore size was prepared from char obtained as a by-product of pyrolysis of Prosopis juliflora biomass. The activation was carried out by a simple process that involved H2O2 treatment followed by microwave pyrolysis. H2O2 impregnation time and microwave power were optimized to obtain biochar with high specific surface area and high adsorption capacity for commercial dyes such as Remazol Brilliant Blue and Methylene Blue. Adsorption parameters such as initial pH of the dye solution and adsorbent dosage were also optimized. Pore size distribution, surface morphology and elemental composition of activated biochar were thoroughly characterized. H2O2 impregnation time of 24h and microwave power of 600W produced nanostructured biochar with narrow and deep pores of 357m(2)g(-1) specific surface area. Langmuir and Langmuir-Freundlich isotherms described the adsorption equilibrium, while pseudo second order model described the kinetics of adsorption., (Copyright © 2016 Elsevier Ltd. All rights reserved.)