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Microalgal biomass can be utilized for the production of value-added chemicals and fuels. Within this research, Chlorella vulgaris biomass left behind after the extraction of lipids and proteins was converted to valuable sugars, organic acids and furanic compounds via hydrolysis/dehydration using dilute aqueous sulfuric acid as a homogeneous catalyst. Under mild conditions, i.e., low temperature and low sulfuric acid concentration, the main products of hydrolysis/dehydration were monomeric sugars (glucose and xylose) and furanic compounds (HMF, furfural) while under more intense conditions (i.e., higher temperature and higher acid concentration), organic acids (propionic, formic, acetic, succinic, lactic, levulinic) were also produced either directly from sugar conversion or via intermediate furans. As a second valorization approach, the residual microalgal biomass was converted to value-added sugar alcohols (sorbitol, glycerol) via hydrogenation/hydrogenolysis reactions over metallic ruthenium catalysts supported on activated carbons (5%Ru/C). It was also shown that a low concentration of sulfuric acid facilitated the conversion of biomass to sugar alcohols by initiating the hydrolysis of carbohydrates to monomeric sugars. Overall, this work aims to propose valorization pathways for a rarely utilized residual biomass towards useful compounds utilized as platform chemicals and precursors for the production of a wide variety of solvents, polymers, fuels, food ingredients, pharmaceuticals and others. [ABSTRACT FROM AUTHOR]

The demand for high-performance bio-based materials towards achieving more sustainable manufacturing and circular economy models is growing significantly. Kraft lignin (KL) is an abundant and highly functional aromatic/phenolic biopolymer, being the main side product of the pulp and paper industry, as well as of the more recent 2nd generation biorefineries. In this study, KL was incorporated into a glassy epoxy system based on the diglycidyl ether of bisphenol A (DGEBA) and an amine curing agent (Jeffamine D-230), being utilized as partial replacement of the curing agent and the DGEBA prepolymer or as a reactive additive. A D-230 replacement by pristine (unmodified) KL of up to 14 wt.% was achieved while KL–epoxy composites with up to 30 wt.% KL exhibited similar thermo-mechanical properties and substantially enhanced antioxidant properties compared to the neat epoxy polymer. Additionally, the effect of the KL particle size was investigated. Ball-milled kraft lignin (BMKL, 10 μm) and nano-lignin (NLH, 220 nm) were, respectively, obtained after ball milling and ultrasonication and were studied as additives in the same epoxy system. Significantly improved dispersion and thermo-mechanical properties were obtained, mainly with nano-lignin, which exhibited fully transparent lignin–epoxy composites with higher tensile strength, storage modulus and glass transition temperature, even at 30 wt.% loadings. Lastly, KL lignin was glycidylized (GKL) and utilized as a bio-based epoxy prepolymer, achieving up to 38 wt.% replacement of fossil-based DGEBA. The GKL composites exhibited improved thermo-mechanical properties and transparency. All lignins were extensively characterized using NMR, TGA, GPC, and DLS techniques to correlate and justify the epoxy polymer characterization results. [ABSTRACT FROM AUTHOR]

Sub‐micro organosolv lignin (OBs) isolated from beechwood biomass, comprising of sub‐micro sized particles (570 nm) with low molecular weight and dispersity and relatively high total phenolic −OH content, is utilized for the production of bio‐based epoxy polymer composites. OBs lignin is incorporated into the glassy epoxy system based on diglycidyl ether of bisphenol A (DGEBA) and aliphatic polyoxypropylene α,ω‐diamine (Jeffamine D‐230), being utilized both as a curing agent, partially replacing D‐230, and as an additive, substituting part of both petroleum‐derived components. Up to 12 wt % replacement of D‐230 by OBs lignin is achieved, whereas approximately 17 wt % of OBs effectively replaces the conventional epoxy polymer. The incorporation of OBs lignin in the polymeric matrix is achieved without the use of any solvent or previous functionalization. Enhanced properties are obtained, with substantial increases in tensile strength, strain, stiffness, glass transition temperature, antioxidant activity, and resistance to solvents. [ABSTRACT FROM AUTHOR]

Two different silica conformations (xerogels and nanoparticles), both formed by the mediation of dendritic poly (ethylene imine), were tested at low pHs for problematic uranyl cation sorption. The effect of crucial factors, i.e., temperature, electrostatic forces, adsorbent composition, accessibility of the pollutant to the dendritic cavities, and MW of the organic matrix, was investigated to determine the optimum formulation for water purification under these conditions. This was attained with the aid of UV-visible and FTIR spectroscopy, dynamic light scattering (DLS), ζ-potential, liquid nitrogen (LN2) porosimetry, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Results highlighted that both adsorbents have extraordinary sorption capacities. Xerogels are cost-effective since they approximate the performance of nanoparticles with much less organic content. Both adsorbents could be used in the form of dispersions. The xerogels, though, are more practicable materials since they may penetrate the pores of a metal or ceramic solid substrate in the form of a precursor gel-forming solution, producing composite purification devices. [ABSTRACT FROM AUTHOR]

Textile effluents pose a massive threat to the aquatic environment, so, sustainable approaches for environmentally friendly multifunctional remediation methods degradation are still a challenge. In this study, composites consisting of bismuth oxyhalide nanoparticles, specifically bismuth oxychloride (BiOCl) nanoplatelets, and lignin-based biochar were synthesized following a one-step hydrolysis synthesis. The simultaneous photocatalytic and adsorptive remediation efficiency of the Biochar–BiOCl composites were studied for the removal of a benchmark azo anionic dye, methyl orange dye (MO). The influence of various parameters (such as catalyst dosage, initial dye concentration, and pH) on the photo-assisted removal was carried out and optimized using the Box–Behnken Design of RSM. The physicochemical properties of the nanomaterials were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, nitrogen sorption, and UV–Vis diffuse reflectance spectroscopy (DRS). The maximum dye removal was observed at a catalyst dosage of 1.39 g/L, an initial dye concentration of 41.8 mg/L, and a pH of 3.15. The experiment performed under optimized conditions resulted in 100% degradation of the MO after 60 min of light exposure. The incorporation of activated biochar had a positive impact on the photocatalytic performance of the BiOCl photocatalyst for removing the MO due to favorable changes in the surface morphology, optical absorption, and specific surface area and hence the dispersion of the photo-active nanoparticles leading to more photocatalytic active sites. This study is within the frames of the design and development of green-oriented nanomaterials of low cost for advanced (waste)water treatment applications. [ABSTRACT FROM AUTHOR]

Fluid Catalytic Cracking (FCC) has traditionally been a key refining process in generating transportation fuels. Recently, the focus on FCC has been further intensified as it plays an increasingly important role in the generation of key building blocks for the petrochemical industry. Nickel is considered as one of the most challenging contaminants in FCC and originates from Ni-containing compounds in petroleum fractions, not only during unit operation but also in handling of the equilibrium and spent catalysts. Despite this critical role it plays throughout the complete lifecycle of an FCC catalyst, the nature of Ni is not yet well understood at various stages of its journey after depositing on the catalyst surface. The main objective of this contribution is the qualitative and quantitative identification of the various possible phases of Ni that are usually present in an equilibrium FCC catalyst (Ecat). A series of conventional and advanced analytical techniques have been employed, including XRF, ICP-AES, PXRD, FT-IR, UV-Vis-NIR, SEM-EDS, TEM/HRTEM and STEM/EXDS, XPS, RAMAN and TPR-H2, on prototype Ni-impregnated SiO2, Al2O3 and USY zeolite samples, Ni-impregnated and lab-deactivated FCC samples, and equilibrium FCC catalysts obtained from different refineries. Detailed analysis of the obtained results on the basis of background information, showed the strengths and weaknesses of the various methods. It was shown that powder x-ray diffraction (pxrd) can be effectively used for the quantitative determination of the NiO (bunsenite) phase at levels representative of equilibrium FCC catalysts. A comparison of conventional versus boron-based Ni-passivation is presented. It was shown that catalysts from boron-based technology (BBT) can keep Ni at a less-reducible state, effectively hindering its deleterious role in FCC operations. [ABSTRACT FROM AUTHOR]

Lignin, being one of the main structural components of lignocellulosic biomass, is considered the most abundant natural source of phenolics and aromatics. Efforts for its valorisation were recently explored as it is mostly treated as waste from heat/energy production via combustion. Among them, polymer-based lignin composites are a promising approach to both valorise lignin and to fine tune the properties of polymers. In this work, organosolv lignin, from beech wood, was used as fillers in a poly (lactic acid) (PLA) matrix. The PLA/lignin composites were prepared using melt mixing of masterbatches with neat PLA in three different lignin contents: 0.5, 1.0 and 2.5 wt%. Lignin was used as-isolated, via the organosolv biomass pretreatment/fractionation process and after 8 h of ball milling. The composites were characterised with Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy, X-ray Diffraction (XRD), and Differential Scanning Calorimetry (DSC). Additionally, their antioxidant activity was assessed with the 2,2-Diphenyil-1-picrylhydrazyl (DPPH) method, the colour was measured with a colorimeter and the mechanical properties were evaluated with tensile testing. Ball milling, at least under the conditions applied in this study, did not induce a further substantial decrease in the already relatively small organosolv lignin primary particles of ~1 μm. All the produced PLA/lignin composites had a uniform dispersion of lignin. Compression-moulded films were successfully prepared, and they were coloured brown, with ball-milled lignin, giving a slightly lighter colour in comparison with the as-received lignin. Hydrogen bonding was detected between the components of the composites, and crystallization of the PLA was suppressed by both lignin, with the suppression being less pronounced by the ball-milled lignin. All composites showed a significantly improved antioxidant activity, and their mechanical properties were maintained for filler content 1 wt%. [ABSTRACT FROM AUTHOR]

The main objective of this study was to investigate the characteristic properties of lignin-modified bitumen with different lignin contents. The first step was the characterization of the physicochemical and thermal properties of the kraft lignin powder along with the determination of its microstructure. This was achieved by carrying out an elemental analysis, Gel Permeation Chromatography (GPC), Thermogravimetric Analysis (TGA)/Derivative Thermogravimetry (DTG), Fourier Transformation Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS) and Confocal Microscopy. After the latter tests, three (3) blends with different lignin contents (5%, 10% and 15% by weight of bitumen) were produced. Characteristic properties such as penetration, softening point, elastic recovery, force ductility, dynamic viscosity and storage stability were determined for the reference bitumen and the three lignin blends. The main conclusion was that kraft lignin powder hardens the conventional bitumen. Specifically, the addition of 15% lignin to the bitumen hardened the blend to such a degree that the bitumen changed category from 50/70 to 35/50 with respect to EN 12591. [ABSTRACT FROM AUTHOR]

Within the frame of this article, briefly but comprehensively, we present the existing knowledge, perspectives, and challenges for the utilization of Layered Double Hydroxides (LDHs) as adsorbents against a plethora of pollutants in aquatic matrixes. The use of LDHs as adsorbents was established by considering their significant physicochemical features, including their textural, structural, morphological, and chemical composition, as well as their method of synthesis, followed by their advantages and disadvantages as remediation media. The utilization of LDHs towards the adsorptive removal of dyes, metals, oxyanions, and emerging pollutants is critically reviewed, while all the reported kinds of interactions that gather the removal are collectively presented. Finally, future perspectives on the topic are discussed. It is expected that this discussion will encourage researchers in the area to seek new ideas for the design, development, and applications of novel LDHs-based nanomaterials as selective adsorbents, and hence to further explore the potential of their utilization also for analytic approaches to detect and monitor various pollutants. [ABSTRACT FROM AUTHOR]

The continuous increase of the demand in merchandise and fuels augments the need of modern approaches for the mass-production of renewable chemicals derived from abundant feedstocks, like biomass, as well as for the water and soil remediation pollution resulting from the anthropogenic discharge of organic compounds. Towards these directions and within the concept of circular (bio)economy, the development of efficient and sustainable catalytic processes is of paramount importance. Within this context, the design of novel catalysts play a key role, with carbon-based nanocatalysts (CnCs) representing one of the most promising class of materials. In this review, a wide range of CnCs utilized for biomass valorization towards valuable chemicals production, and for environmental remediation applications are summarized and discussed. Emphasis is given in particular on the catalytic production of 5-hydroxymethylfurfural (5-HMF) from cellulose or starch-rich food waste, the hydrogenolysis of lignin towards high bio-oil yields enriched predominately in alkyl and oxygenated phenolic monomers, the photocatalytic, sonocatalytic or sonophotocatalytic selective partial oxidation of 5-HMF to 2,5-diformylfuran (DFF) and the decomposition of organic pollutants in aqueous matrixes. The carbonaceous materials were utilized as stand-alone catalysts or as supports of (nano)metals are various types of activated micro/mesoporous carbons, graphene/graphite and the chemically modified counterparts like graphite oxide and reduced graphite oxide, carbon nanotubes, carbon quantum dots, graphitic carbon nitride, and fullerenes. [ABSTRACT FROM AUTHOR]

The management of municipal and industrial organic solid wastes has become one of the most critical environmental problems in modern societies. Nowadays, commonly used management techniques are incineration, composting, and landfilling, with the former one being the most common for hazardous organic wastes. An alternative eco-friendly method that offers a sustainable and economically viable solution for hazardous wastes management is fast pyrolysis, being one of the most important thermochemical processes in the petrochemical and biomass valorization industry. The objective of this work was to study the application of fast pyrolysis for the valorization of three types of wastes, i.e., petroleum-based sludges and sediments, residual paints left on used/scrap metal packaging, and creosote-treated wood waste, towards high-added-value fuels, chemicals, and (bio)char. Fast pyrolysis experiments were performed on a lab-scale fixed-bed reactor for the determination of product yields, i.e., pyrolysis (bio)oil, gases, and solids (char). In addition, the composition of (bio)oil was also determined by Py/GC-MS tests. The thermal pyrolysis oil from the petroleum sludge was only 15.8 wt.% due to the remarkably high content of ash (74 wt.%) of this type of waste, in contrast to the treated wood and the residual paints (also containing 30 wt.% inorganics), which provided 46.9 wt.% and 35 wt.% pyrolysis oil, respectively. The gaseous products ranged from ~7.9 wt.% (sludge) to 14.7 (wood) and 19.2 wt.% (paints), while the respective solids (ash, char, reaction coke) values were 75.1, 35, and 36.9 wt.%. The thermal (non-catalytic) pyrolysis of residual paint contained relatively high concentrations of short acrylic aliphatic ester (i.e., n-butyl methacrylate), being valuable monomers in the polymer industry. The use of an acidic zeolitic catalyst (ZSM-5) for the in situ upgrading of the pyrolysis vapors induced changes on the product yields (decreased oil due to cracking reactions and increased gases and char/coke), but mostly on the pyrolysis oil composition. The main effect of the ZSM-5 zeolite catalyst was that, for all three organic wastes, the catalytic pyrolysis oils were enriched in the value-added mono-aromatics (BTX), especially in the case of the treated wood waste and residual paints. The non-condensable gases were mostly consisting of CO, CO2, and different amounts of C1–C4 hydrocarbons, depending on initial feed and use or not of the catalyst that increased the production of ethylene and propylene. [ABSTRACT FROM AUTHOR]

This review sheds light on urgent questions that arise from the need to replace a polymer resin,–poly(ethylene terephthalate), which represents 7.7% market-share in the global plastic demand (Plastics–the Facts 2019), by renewable alternatives. The main question that this review will address is: what are the most promising PET replacements made from biomass? Currently, under debate is naturally its biobased counterpart bio-PET (or even recycle rPET), as well as other aromatic key-players with comparable thermo-mechanical performance and enhanced barrier properties, such as poly(ethylene 2,5-furandicarboxylate) (PEF) and poly(trimethylene 2,5-furandicarboxylate) (PTF). They are most adequate for packaging, but not restricted to. Additional alternatives are the miscellaneous of lignin-based thermoplastic polymers, although the technology involved in this latter case is still premature. (Bio)degradable aliphatic polyesters, despite their typical inferior thermo-mechanical properties, can also play a role e.g., among PET fiber industry applications. Poly(lactic acid) (PLA) is the most developed renewable polyester, already a commercial reality. All biobased polymers reviewed face a major hindrance for their wider deployment their cost-competitiveness. A pertinent question arises then: Are these alternatives, or will they be, economically feasible? Social, political and legal frameworks together with supportive financial schemes are boosting rapid changes. In the future, most probably more than one polymer will come to the market and will be used in some of the panoply of PET applications. This evaluation overviews sustainability issues, including perspectives on their green synthesis. Moreover, this review does also not neglect the accumulation of plastics waste in the environment and the inherent challenges of polymers' end-of-life. Approximately 8 M tons of polymers waste leaks into the environment each year, a fact not disconnected to PET's non-biodegradability and still insufficient collection and recycling rates. [ABSTRACT FROM AUTHOR]

• Small Ag crystals (25–35 nm) at high loadings via in situ reduction/deposition. • Larger Ag crystals (45–60 nm) on nonporous, nonacidic supports favor PO selectivity. • NaCl promotion is "reversible" due to gradual removal of Cl ions as allyl chloride. • Addition of steam in the feed enhances PO formation without reducing activity. • The supported Ag catalysts were stable over prolonged reaction testing. The direct gas-phase epoxidation of propylene using molecular oxygen remains a challenging method to produce propylene oxide (PO) with minimum environmental impact. The epoxidation of propylene using Ag catalysts supported on non-porous or low surface area supports, such as α-Al 3 O 2 , CaCO 3 , TiO 2 rutile, SiO 2 and ZrO 2 , as well as on meso/macroporous ZrO 2 and TiO 2 anatase, was thoroughly investigated in the present work. The catalysts (Ag loading 10–50 wt. %) were prepared by wet impregnation followed by in-situ reduction with amines or by ex situ treatment with H 2 at 350 °C. The combination of moderate surface area (ca. 60 m2/g) of the meso/macroporous ZrO 2 and TiO 2 anatase with the in situ reduction with amines method offered a relatively high Ag dispersion and small crystallite size of 25–35 nm, even at the high loading of 50 wt.%. Propylene conversion was as high as ca. 40% in the temperature range of 200–320 °C, depending on the type of the support and the preparation method, with the mesoporous ZrO 2 and the amines reduction method affording the most active catalysts. The selectivity of PO was maximized (ca. 6%) at ∼220–260 °C, i.e. 6.1% at 33.0% conversion for the TiO 2 rutile amine reduced catalyst. Promotion of the catalysts with NaCl (2–5 wt.%), led to significantly lower reactivity (conversion ≤ 15%) even at high temperatures, but the selectivity to PO increased up to ca. 14%, with the low surface area ZrO 2 and the TiO 2 rutile based catalysts being the most selective. However, propylene tends to react also with the chloride ions, being on the promoted catalyst surface, leading to allyl chloride co-production, thus leading to gradual decrease of Cl− ions and loss of their beneficial effect on PO formation. Co-feeding of the reactant gas mixture with steam offered an alternative method of promoting PO production, even in the absence of NaCl, with the TiO 2 rutile and CaCO 3 based catalysts being the most effective via this route. [ABSTRACT FROM AUTHOR]

Commercial micro/mesoporous activated carbons were utilized as metal-free catalysts for the desulfurization of a model fuel, i.e. 4,6-dimethyldibenzothiophene (4,6-DMDBT) in hexadecane under ambient conditions. Both adsorption and catalytic oxidation were investigated as means of 4,6-DMDBT removal. The effect of chemical modification/oxidation of the carbon surface via treatment with two different acids (HNO3 or H2SO4) aiming to introduce additional functional groups was also investigated. The catalysts were characterized by FT-IR spectroscopy, N2 porosimetry, potentiometric titration, Boehm titration, and SEM-EDX, while adsorption and catalytic oxidation activity towards sufloxides and sulfones were assessed by GC-MS and UV-Vis analysis. The surface chemistry of the carbons, expressed by the density of the acidic functional groups, was found to be the most critical parameter with regard to adsorption or to catalytic oxidative performance. The surface modification of carbons by oxidation had a positive impact on the catalytic oxidation activity, leading to a 100% conversion of 4,6-DMDBT towards the corresponding sulfoxide and sulfone, compared to 67% with the parent non-oxidized carbon. Reusability tests showed that the oxidation activity of the carbons can be maintained for at least 5 cycles. [ABSTRACT FROM AUTHOR]

The ICGC-9 was organized by the Association of Greek Chemists (AGC) in collaboration with the IUPAC Interdivisional Committee on Green Chemistry for Sustainable Development (ICGCSD). Keywords: Green Chemistry; ICGC series; ICGC-9; IUPAC EN Green Chemistry ICGC series ICGC-9 IUPAC 463 464 2 07/14/23 20230501 NES 230501 The 9th IUPAC International Conference on Green Chemistry (ICGC-9), took place in Athens, Greece, on 5th-9th September 2022 at Zappeion Megaron, offering the choice of virtual participation. Green Chemistry, ICGC-9, IUPAC, ICGC series. [Extracted from the article]

Acetone and ethanol extraction of lignin deposits from the surface of hydrothermally (liquid hot water) pretreated beech wood biomass alleviates the lignin inhibitory effects during enzymatic hydrolysis of cellulose to glucose and boosts the enzymatic digestibility to high values (≈70 %). Characterization of the extracted lignins (FTIR, pyrolysis/GC–MS, differential thermogravimetry, gel permeation chromatography) indicated high purity, low molecular weight, and features that suggest that it consists mainly of fragments of the native wood lignin partially depolymerized and recondensed on the biomass surface during the hydrothermal pretreatment. The pyrolysis products of the extracted surface lignins suggest their high potential as a feedstock for the production of high added value phenolic compounds. When the enzymatic hydrolysis of the pretreated and extracted biomass solids was assisted by mild wet milling, near complete cellulose digestibility (≥95 %) could be achieved. In the context of the biorefinery and whole‐biomass valorization concept, it was also shown that the hydrothermally (hemicellulose‐deficient) pretreated and delignified biomass solids could be also successfully used for the production of crude cellulase from Trichoderma reesei cultures, providing a simple and low‐cost method for the complementary production of cellulases by utilizing fractions of the integrated hydrolysis process. Boosting biomass enzymatic digestibility: Acetone and ethanol extraction of lignin deposits from the surface of hydrothermally (liquid hot water) pretreated beech wood biomass alleviates the lignin inhibitory effects during enzymatic hydrolysis of cellulose to glucose and boosts the enzymatic digestibility to high values (≈70 %). [ABSTRACT FROM AUTHOR]

Abstract: Furfural takes an important position in hemicelluloses biorefinery platforms. It can be converted into a wide range of chemicals. One important valorization route is the catalytic hydrogenation. Whereas molecular hydrogen is mostly used in industrial hydrogenation processes, recent studies also showed that alcohols can be used as reductants from which hydrides can be transferred catalytically to furfural. This process is often assisted by the formation of significant amounts of side products, in despite of high yields to the hydrogenolysis product 2‐methylfuran. The present work explores the catalytic behavior in batch and continuous flow of mono‐ and bimetallic nickel catalysts supported on activated carbon for the catalytic transfer hydrogenation of furfural in isopropanol. [ABSTRACT FROM AUTHOR]

ZSM-5-containing catalytic additives are widely used in oil refineries to boost light olefin production and improve gasoline octanes in the Fluid Catalytic Cracking (FCC) process. Under the hydrothermal conditions present in the FCC regenerator (typically >700 °C and >8% steam), FCC catalysts and additives are subject to deactivation. Zeolites (e.g., Rare Earth USY in the base catalyst and ZSM-5 in Olefins boosting additives) are prone to dealumination and partial structural collapse, thereby losing activity, micropore surface area, and undergoing changes in selectivity. Fresh catalyst and additives are added at appropriate respective levels to the FCC unit on a daily basis to maintain overall targeted steady-state (equilibrated) activity and selectivity. To mimic this process under accelerated laboratory conditions, a commercial P/ZSM-5 additive was hydrothermally equilibrated via a steaming process at two temperatures: 788 °C and 815 °C to simulate moderate and more severe equilibration industrial conditions, respectively. n-Dodecane was used as probe molecule and feed for micro-activity cracking testing at 560 °C to determine the activity and product selectivity of fresh and equilibrated P-doped ZSM-5 additives. The fresh/calcined P/ZSM-5 additive was very active in C12 cracking while steaming limited its activity, i.e., at catalyst-to-feed (C/F) ratio of 1, about 70% and 30% conversion was obtained with the fresh and steamed additives, respectively. A greater activity drop was observed upon increasing the hydrothermal deactivation severity due to gradual decrease of total acidity and microporosity of the additives. However, this change in severity did not result in any selectivity changes for the LPG (liquefied petroleum gas) olefins as the nature (Brønsted-to-Lewis ratio) of the acid/active sites was not significantly altered upon steaming. Steam deactivation of ZSM-5 had also no significant effect on aromatics formation which was enhanced at higher conversion levels. Coke remained low with both fresh and steam-deactivated P/ZSM-5 additives. [ABSTRACT FROM AUTHOR]

The hydroisomerisation/hydrocracking properties of Ni-zeolite catalysts (H-MFI and H-Beta) are studied using n-hexadecane as model compound and compared with those of Ni/ASA (amorphous silica-alumina) as reference catalyst. In the case of H-Beta, the effect of the introduction of mesoporosity by controlled desilication is also investigated. The results indicate that Ni on desilicated H-Beta catalysts shows very interesting characteristics for the potential use in the production of biofuel from vegetable/algal oil, or the upgrading of biomass-derived Fischer-Tropsch waxes. Ni/H-Beta shows lower activity with respect to Ni/H-MFI, but significantly lower formation of gases and much better hydroisomerisation activity. The introduction of mesoporosity by desilication enhances the activity, while still maintaining an acceptable gas formation and good hydroisomerisation properties. Furthermore, the desilication treatment improves the stability with respect to carbon formation. [ABSTRACT FROM AUTHOR]

Recently, the adsorption-based environmental remediation techniques have gained a considerable attention, due to their economic viability and simplicity over other methods. Hence, detailed presentation and analysis were herein focused on describing the role of biochar in oil spill removal. Oil removal by utilizing biochar is assumed as a green-oriented concept. Biochar is a carbon-rich low-cost material with high porosity and specific surface chemistry, with a tremendous potentiality for oil removal from aqueous solutions. Oil sorption properties of biochar mainly depend on the biochar production/synthesis method, and the biomass feedstock type. In order to preserve the stability of functional groups in the structure, biochar needs to be produced/activated at low temperatures (<700 ᵒC). In general, biochar derived from biomass containing high lignin content via slow pyrolysis is more favorable for oil removal. Exceptional characteristics of biochar which intensify the oil removal capability such as hydrophobicity, oleophilicity or/and specific contaminant-surface interaction of biochar can be enhanced and be tuned by chemical and physical activation methods. Considering all the presented results, future perspectives such as the examination of biochar efficacy on oil removal efficiency in multi-element contaminated aqueous solutions to identify the best biomass feedstocks, the production protocols and large-scale field trials, are also discussed. [Display omitted] • Physical and chemical methods of oil spill removal are comprehensively discussed. • Secondary pollution and high cost of operation, hinder utilization of these methods. • Utilizing biochar for the remediation of oil spill is a green oriented concept. • Modified biochar have shown a significant enhance in oil uptake. • Large scale application, cost-benefit analysis, regeneration studies are lacking. Successful large-scale field trials demonstrated high performance of biochar as a green material for removing oil spills, at multi-element contaminated systems. [ABSTRACT FROM AUTHOR]

In water and wastewater, phosphate anions are considered critical contaminants because they cause algae blooms and eutrophication. The present work aims at studying the removal of phosphate anions from aqueous solutions using silica particles functionalized with polyethylenimine. The parameters affecting the adsorption process such as pH, initial concentration, adsorbent dose, and the presence of competitive anions, such as carbonate, nitrate, sulfate and chromate ions, were studied. Equilibrium studies were carried out to determine their sorption capacity and the rate of phosphate ions uptake. The adsorption isotherm data fitted well with the Langmuir and Sips model. The maximum sorption capacity was 41.1 mg/g at pH 5, which decreased slightly at pH 7. The efficiency of phosphate removal adsorption increased at lower pH values and by increasing the adsorbent dose. The maximum phosphate removal was 80% for pH 5 and decreased to 75% for pH 6, to 73% for pH 7 and to 70% for pH 8, for initial phosphate concentration at about 1 mg/L and for a dose of adsorbent 100 mg/L. The removal rate was increased with the increase of the adsorbent dose. For example, for initial phosphate concentration of 4 mg/L the removal rate increased from 40% to 80% by increasing the dose from 0.1 to 2.0 g/L at pH 7. The competitive anions adversely affected phosphate removal. Though they were also found to be removed to a certain extent. Their co-removal provided an adsorbent which might be very useful for treating waters with low-level multiple contaminant occurrence in natural or engineered aquatic systems. [ABSTRACT FROM AUTHOR]

Mesoporous silica-based nanoparticles (MSNs) are considered promising drug carriers because of their ordered pore structure, which permits high drug loading and release capacity. The dissolution of Si and Ca from MSNs can trigger osteogenic differentiation of stem cells towards extracellular matrix calcification, while Mg and Sr constitute key elements of bone biology and metabolism. The aim of this study was the synthesis and characterization of sol–gel-derived MSNs co-doped with Ca, Mg and Sr. Their physico-chemical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF), Brunauer Emmett Teller and Brunauer Joyner Halenda (BET/BJH), dynamic light scattering (DLS) and ζ-potential measurements. Moxifloxacin loading and release profiles were assessed with high performance liquid chromatography (HPLC) cell viability on human periodontal ligament fibroblasts and their hemolytic activity in contact with human red blood cells (RBCs) at various concentrations were also investigated. Doped MSNs generally retained their textural characteristics, while different compositions affected particle size, hemolytic activity and moxifloxacin loading/release profiles. All co-doped MSNs revealed the formation of hydroxycarbonate apatite on their surface after immersion in simulated body fluid (SBF) and promoted mitochondrial activity and cell proliferation. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is an abundant renewable source of chemicals and fuels. Lignin, one of biomass main structural components being widely available as by-product in the pulp and paper industry and in the process of second generation bioethanol, can provide phenolic and aromatic compounds that can be utilized for the manufacture of a wide variety of polymers, fuels, and other high added value products. The effective depolymerisation of lignin into its primary building blocks remains a challenge with regard to conversion degree and monomers selectivity and stability. This review article focuses on the state of the art in the liquid phase reductive depolymerisation of lignin under relatively mild conditions via catalytic hydrogenolysis/hydrogenation reactions, discussing the effect of lignin type/origin, hydrogen donor solvents, and related transfer hydrogenation or reforming pathways, catalysts, and reaction conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highly active bifunctional Ni/WO 3 -ZrO 2 catalyst for phenol hydrodeoxygenation to cyclohexane. • Beneficial acidic and textural properties offered by WO 3 addition to ZrO 2. • Efficient HDO upgrading of catalytic bio-oil to cycloalkanes and alkylbenzenes with Ni/WO 3 -ZrO 2 at mild conditions. The hydrodeoxygenation of pure phenol in hexane solution and of catalytic biomass fast pyrolysis oil (bio-oil) over 10 %Ni/ZrO 2 and 10 %Ni/WO 3 -ZrO 2 catalysts was investigated in the present study, at relatively mild conditions (ca. 50−250 °C, 30 bar H 2) in a continuous flow high-pressure fixed bed reactor. The catalysts were characterized for their structural, porosity, redox and acidic/basic properties which were used to rationalize the observed catalytic performance. The 10 %Ni/ZrO 2 catalyst was very active and selective towards cyclohexanol in the phenol HDO experiments (100 % conversion and selectivity at 110 °C) but the enhanced acidity offered by the addition WO 3 in ZrO 2 was necessary to succeed a complete hydrodeoxygenation of phenol to cyclohexane at the low temperature of 150 °C with the 10 %Ni/WO 3 -ZrO 2 catalyst. This catalyst was also proven very active in the hydrodeoxygenation of the catalytic bio-oil which consisted of mono-aromatics (i.e. alkyl-benzenes) and PAHs (mainly naphthalenes and indenes), and fewer oxygenated compounds (i.e. alkyl-phenols and benzofurans), providing a product oil containing mainly alkyl-cycloalkanes and fewer alkyl-benzenes, at the mild conditions of 210 °C and 30 bar H 2. [ABSTRACT FROM AUTHOR]