Characterisation of waste derived intermediate pyrolysis oils for use as diesel engine fuels

This paper studies the characteristics of intermediate pyrolysis oils derived from sewage sludge and de-inking sludge (a paper industry residue), with a view to their use as fuels in a diesel engine. The feedstocks were dried and pelletised, then pyrolysed in the Pyroformer intermediate pyrolysis system. The organic fraction of the oils was separated from the aqueous phase and characterised. This included elemental and compositional analysis, heating value, cetane index, density, viscosity, surface tension, flash point, total acid number, lubricity, copper corrosion, water, carbon residue and ash content. Most of these results are compared with commercial diesel and biodiesel. Both pyrolysis oils have high carbon and hydrogen contents and their higher heating values compare well with biodiesel. The water content of the pyrolysis oils is reasonable and the flash point is found to be high. Both pyrolysis oils have good lubricity, but show some corrosiveness. Cetane index is reduced, which may influence ignition. Also viscosity is increased, which may influence atomisation quality. Carbon residue and ash content are both high, indicating potential deposition problems. Compared with de-inking sludge pyrolysis oil (DSPO), sewage sludge pyrolysis oil (SSPO) has a higher heating value, but higher corrosiveness and viscosity. The conclusions are that both intermediate pyrolysis oils will be able to provide sufficient heat when used in diesel engine; however poor combustion and carbon deposition may be encountered. Blending of these pyrolysis oils with diesel or biodiesel could overcome these problems and is recommended for further investigation.

Dry powder inhalation of macromolecules using novel PEG-co-polyester microparticle carriers

This study investigated optimizing the formulation parameters for encapsulation of a model mucinolytic enzyme, a-chymotrypsin (a-CH), within a novel polymer; poly(ethylene glycol)-co-poly(glycerol adipate-co-?-pentadecalactone), PEG-co-(PGA-co-PDL) which were then applied to the formulation of DNase I. a-CH or DNase I loaded microparticles were prepared via spray drying from double emulsion (w(1)/o/w(2)) utilizing chloroform (CHF) as the organic solvent, l-leucine as a dispersibility enhancer and an internal aqueous phase (w(1)) containing PEG4500 or Pluronic(®) F-68 (PLF68). a-CH released from microparticles was investigated for bioactivity using the azocasein assay and the mucinolytic activity was assessed utilizing the degradation of mucin suspension assay. The chemical structure of PEG-co-(PGA-co-PDL) was characterized by (1)H NMR and FT-IR with both analyses confirming PEG incorporated into the polymer backbone, and any unreacted units removed. Optimum formulation a-CH-CHF/PLF68, 1% produced the highest bioactivity, enzyme encapsulation (20.08±3.91%), loading (22.31±4.34µg/mg), FPF (fine particle fraction) (37.63±0.97%); FPD (fine particle dose) (179.88±9.43µg), MMAD (mass median aerodynamic diameter) (2.95±1.61µm), and the mucinolytic activity was equal to the native non-encapsulated enzyme up to 5h. DNase I-CHF/PLF68, 1% resulted in enzyme encapsulation (17.44±3.11%), loading (19.31±3.27µg/mg) and activity (81.9±2.7%). The results indicate PEG-co-(PGA-co-PDL) can be considered as a potential biodegradable polymer carrier for dry powder inhalation of macromolecules for treatment of local pulmonary diseases.

Intermediate pyrolysis of biomass energy pellets for producing sustainable liquid, gaseous and solid fuels

This work describes the use of intermediate pyrolysis system to produce liquid, gaseous and solid fuels from pelletised wood and barley straw feedstock. Experiments were conducted in a pilot-scale system and all products were collected and analysed. The liquid products were separated into an aqueous phase and an organic phase (pyrolysis oil) under gravity. The oil yields were 34.1 wt.% and 12.0 wt.% for wood and barley straw, respectively. Analysis found that both oils were rich in heterocyclic and phenolic compounds and have heating values over 24 MJ/kg. The yields of char for both feedstocks were found to be about 30 wt.%, with heating values similar to that of typical sub-bituminous class coal. Gas yields were calculated to be approximately 20 wt.%. Studies showed that both gases had heating values similar to that of downdraft gasification producer gas. Analysis on product energy yields indicated the process efficiency was about 75%. © 2014 Elsevier Ltd. All rights reserved.

Hydrothermally stable, conformal, sulfated zirconia monolayer catalysts for glucose conversion to 5-HMF

The grafting and sulfation of zirconia conformal monolayers on SBA-15 to create mesoporous catalysts of tunable solid acid/base character is reported. Conformal zirconia and sulfated zirconia (SZ) materials exhibit both Brönsted and Lewis acidity, with the Brönsted/Lewis acid ratio increasing with film thickness and sulfate content. Grafted zirconia films also exhibit amphoteric character, whose Brönsted/Lewis acid site ratio increases with sulfate loading at the expense of base sites. Bilayer ZrO2/SBA-15 affords an ordered mesoporous material with a high acid site loading upon sulfation and excellent hydrothermal stability. Catalytic performance of SZ/SBA-15 was explored in the aqueous phase conversion of glucose to 5-HMF, delivering a 3-fold enhancement in 5-HMF productivity over nonporous SZ counterparts. The coexistence of accessible solid basic/Lewis acid and Brönsted acid sites in grafted SZ/SBA-15 promotes the respective isomerization of glucose to fructose and dehydration of reactively formed fructose to the desired 5-HMF platform chemical.

Novel input-output prediction approach for biomass pyrolysis

Biomass pyrolysis to bio-oil is one of the promising sustainable fuels. In this work, relation between biomass feedstock element characteristic and pyrolysis process outputs was explored. The element characteristics considered in this study include moisture, ash, fix carbon, volatile matter, carbon, hydrogen, nitrogen, oxygen, and sulphur. A semi-batch fixed bed reactor was used for biomass pyrolysis with heating rate of 30 °C/min from room temperature to 600 °C and the reactor was held at 600 °C for 1 h before cooling down. Constant nitrogen flow rate of 5 L/min was provided for anaerobic condition. Rice husk, Sago biomass and Napier grass were used in the study to form different element characteristic of feedstock by altering mixing ratio. Comparison between each element characteristic to total produced bio-oil yield, aqueous phase bio-oil yield, organic phase bio-oil yield, higher heating value of organic phase bio-oil, and organic bio-oil compounds was conducted. The results demonstrate that process performance is associated with feedstock properties, which can be used as a platform to access the process feedstock element acceptance range to estimate the process outputs. Ultimately, this work evaluated the element acceptance range for proposed biomass pyrolysis technology to integrate alternative biomass species feedstock based on element characteristic to enhance the flexibility of feedstock selection.

Sustained delivery of salbutamol and beclometasone from spray-dried double emulsions

The sustained delivery of multiple agents to the lung offers potential benefits to patients. This study explores the preparation of highly respirable dual-loaded spray-dried double emulsions. Spray-dried powders were produced from water-in-oil-in-water (w/o/w) double emulsions, containing salbutamol sulphate and/or beclometasone dipropionate in varying phases. The double emulsions contained the drug release modifier polylactide co-glycolide (PLGA 50 : 50) in the intermediate organic phase of the original micro-emulsion and low molecular weight chitosan (Mw<190 kDa: emulsion stabilizer) and leucine (aerosolization enhancer) in the tertiary aqueous phase. Following spray-drying resultant powders were physically characterized: with in vitro aerosolization performance and drug release investigated using a Multi-Stage Liquid Impinger and modified USP II dissolution apparatus, respectively. Powders generated were of a respirable size exhibiting emitted doses of over 95% and fine particle fractions of up to 60% of the total loaded dose. Sustained drug release profiles were observed during dissolution for powders containing agents in the primary aqueous and secondary organic phases of the original micro-emulsion; the burst release of agents was witnessed from the tertiary aqueous phase. The novel spray-dried emulsions from this study would be expected to deposit and display sustained release character in the lung.

Carbon nanotube-supported metal catalysts for NOx reduction using hydrocarbon reductants. Part 1:catalyst preparation, characterization and NOx reduction characteristics

A dual catalyst system for the Selective Catalytic Reduction of NOx with hydrocarbons (HC-SCR), including distinct low and high temperature formulations, is proposed as a means to abate NOx emissions from diesel engines. Given that satisfactory high temperature HC-SCR catalysts are already available, this work focuses on the development of an improved low temperature formulation. Pt supported on multiwalled carbon nantubes (MWCNTs) was found to exhibit superior NOx reduction activity in comparison with Pt/Al2O3, while the MWCNT support displayed a higher resistance to oxidation than activated carbon. Refluxing the MWCNT support in a 1:1 mixture of H2SO4 and HNO3 prior to the metal deposition step proved to be beneficial for the metal dispersion and the NOx reduction performance of the resulting catalysts. This support effect is ascribed to the increased Brønsted acidity of the acid-treated MWCNTs, which in turn enhances the partial oxidation of the hydrocarbon reductant. Further improvements in the HC-SCR performance of MWCNT-based formulations were achieved using a 3:1 Pt–Rh alloy as the supported phase.

Dual affinity method for plasmid DNA purification in aqueous two-phase systems

The DNA binding fusion protein, LacI-His6-GFP, together with the conjugate PEG-IDA-Cu(II) (10 kDa) was evaluated as a dual affinity system for the pUC19 plasmid extraction from an alkaline bacterial cell lysate in poly(ethylene glycol) (PEG)/dextran (DEX) aqueous two-phase systems (ATPS). In a PEG 600-DEX 40 ATPS containing 0.273 nmol of LacI fusion protein and 0.14% (w/w) of the functionalised PEG-IDA-Cu(II), more than 72% of the plasmid DNA partitioned to the PEG phase, without RNA or genomic DNA contamination as evaluated by agarose gel electrophoresis. In a second extraction stage, the elution of pDNA from the LacI binding complex proved difficult using either dextran or phosphate buffer as second phase, though more than 75% of the overall protein was removed in both systems. A maximum recovery of approximately 27% of the pCU19 plasmid was achieved using the PEG-dextran system as a second extraction system, with 80-90% of pDNA partitioning to the bottom phase. This represents about 7.4 microg of pDNA extracted per 1 mL of pUC19 desalted lysate.

Three-dimensional nitrogen-doped graphene supported molybdenum disulfide nanoparticles as an advanced catalyst for hydrogen evolution reaction

An efficient three-dimensional (3D) hybrid material of nitrogen-doped graphene sheets (N-RGO) supporting molybdenum disulfide (MoS2) nanoparticles with high-performance electrocatalytic activity for hydrogen evolution reaction (HER) is fabricated by using a facile hydrothermal route. Comprehensive microscopic and spectroscopic characterizations confirm the resulting hybrid material possesses a 3D crumpled few-layered graphene network structure decorated with MoS2 nanoparticles. Electrochemical characterization analysis reveals that the resulting hybrid material exhibits efficient electrocatalytic activity toward HER under acidic conditions with a low onset potential of 112 mV and a small Tafel slope of 44 mV per decade. The enhanced mechanism of electrocatalytic activity has been investigated in detail by controlling the elemental composition, electrical conductance and surface morphology of the 3D hybrid as well as Density Functional Theory (DFT) calculations. This demonstrates that the abundance of exposed active sulfur edge sites in the MoS2 and nitrogen active functional moieties in N-RGO are synergistically responsible for the catalytic activity, whilst the distinguished and coherent interface in MoS 2 /N-RGO facilitates the electron transfer during electrocatalysis. Our study gives insights into the physical/chemical mechanism of enhanced HER performance in MoS2/N-RGO hybrids and illustrates how to design and construct a 3D hybrid to maximize the catalytic efficiency.

Effect of preparation conditions on the formation of the active phase of carbon fiber catalytic systems for the low-temperature oxidation of carbon monoxide

We studied the effects of the composition of impregnating solution and heat treatment conditions on the activity of catalytic systems for the low-temperature oxidation of CO obtained by the impregnation of Busofit carbon-fiber cloth with aqueous solutions of palladium, copper, and iron salts. The formation of an active phase in the synthesized catalysts at different stages of their preparation was examined with the use of differential thermal and thermogravimetric analyses, X-ray diffraction analysis, X-ray photoelectron spectroscopy, and elemental spectral analysis. The catalytic system prepared by the impregnation of electrochemically treated Busofit with the solutions of PdCl, FeCl, CuBr, and Cu(NO ) and activated under optimum conditions ensured 100% CO conversion under a respiratory regime at both low (0.03%) and high (0.5%) carbon monoxide contents of air. It was found that the activation of a catalytic system at elevated temperatures (170-180°C) leads to the conversion of Pd(II) into Pd(I), which was predominantly localized in a near-surface layer. The promoting action of copper nitrate consists in the formation of a crystalline phase of the rhombic atacamite CuCl(OH). The catalyst surface is finally formed under the conditions of a catalytic reaction, when a joint Pd(I)-Cu(I) active site is formed. © 2014 Pleiades Publishing, Ltd.

Identifying the active phase in Cs-promoted MgO nanocatalysts for triglyceride transesterification

Background: Biodiesel is a clean-burning, renewable and biodegradable diesel fuel substitute derived from animal fats and plant oils, which may play an important role in replacing diminishing fossil fuel reserves and combating climate change. Conventional biodiesel production uses soluble base catalysts, such as Na or K alkoxides, to convert oils into fuel, and as a result requires energy intensive aqueous quench cycles to isolate the biodiesel product. Results: Cs-doping nanoparticulate MgO, prepared via a novel, supercritical sol-gel method, yields a solid base catalyst with improved activity for the transesterification of pure triacylglycerides (TAGs) and olive oil. Conclusion: Here, X-ray absorption spectroscopy (XAS) is used to probe the local chemical environment of Cs atoms in order to identify the nature of the catalytically active species as CsMg(CO)(HO). © 2013 Society of Chemical Industry.

Enhanced selective aerobic alcohol oxidation through nanoengineered catalyst supports

The selective conversion of alcohols to their carbonyl derivatives is a critical step towards a sustainable chemical industry. Heterogeneous Pd catalysts represent some of the most active systems known, even so further studies into the active species and role of support are required. Through controlling support mesostructure, using non-interconnected SBA-15 and interlinked SBA-16 and KIT-6, we have evaluated the role of pore architecture on supported Pd nanoparticles and their subsequent activity for liquid phase aerobic allylic alcohol selective oxidation.[1,2] These synthesised silica supports exhibit high surface areas (>800 m2g-1), and similar mesopore diameters (3.5 to 5 nm), but differ in their pore connectivity and arrangement; p6mm (SBA-15), I3mm (SBA-16) and I3ad (KIT-6). When evaluated alongside commercial non-mesoporous silica (200 m2 g-1) they promote enhanced Pd dispersion with interpenetrating assemblies providing further elevation. Macropore introduction into SBA-15, producing a hierarchical macro-mesoporous silica (MM-SBA-15), allows control over mesopore length and accessibility which escalates Pd distribution to levels akin to KIT-6 and SBA-16. Controlling dispersion, and likewise nanoparticle size, is thus facilitated through the choice of support and additionally Pd loading, with cluster sizes spanning 3.2 to 0.8 nm. X-ray spectroscopies indicate nanoparticles are PdO terminated with the oxide content a function of dispersion. Kinetic studies allude to surface PdO being the active site responsible, with a constant TOF observed, independent of loading and support. This confirms activity is governed by PdO density, whilst also overruling internal mass diffusion constraints. MM-SBA-15 facilitates superior activity and TOFs for long chain acyclic terpene alcohols due to reduced internal mass transport constraints.

Glycerol valorization:dehydration to acrolein over silica-supported niobia catalysts

The catalytic dehydration of glycerol to acrolein is investigated over silica-supported niobia catalysts in a continuous fixed-bed gas-phase reactor. Various supported niobia catalysts are prepared and characterized using surface analysis and spectroscopic methods (XRD, UV-Vis, XPS, N2 adsorption), as well as with ammonia adsorption microcalorimetry. Good results are obtained with initial glycerol conversions of over 70% and with 50-70% selectivity to acrolein. We investigate the influence of changing the catalyst acid strength by varying the niobia content and catalyst calcination temperature. Glycerol conversion and acrolein selectivity depend on the surface acid strength. Catalyst deactivation by coking is also observed, but simple oxidative treatment in air restores the activity of the catalysts completely. © The Author(s) 2010.

Stabilization of catalyst particles against sintering on oxide supports with high oxygen ion lability exemplified by Ir-catalyzed decomposition of N2O

Iridium nanoparticles deposited on a variety of surfaces exhibited thermal sintering characteristics that were very strongly correlated with the lability of lattice oxygen in the supporting oxide materials. Specifically, the higher the lability of oxygen ions in the support, the greater the resistance of the nanoparticles to sintering in an oxidative environment. Thus with γ-Al2O3 as the support, rapid and extensive sintering occurred. In striking contrast, when supported on gadolinia-ceria and alumina-ceria-zirconia composite, the Ir nanoparticles underwent negligible sintering. In keeping with this trend, the behavior found with yttria-stabilized zirconia was an intermediate between the two extremes. This resistance, or lack of resistance, to sintering is considered in terms of oxygen spillover from support to nanoparticles and discussed with respect to the alternative mechanisms of Ostwald ripening versus nanoparticle diffusion. Activity towards the decomposition of N2O, a reaction that displays pronounced sensitivity to catalyst particle size (large particles more active than small particles), was used to confirm that catalytic behavior was consistent with the independently measured sintering characteristics. It was found that the nanoparticle active phase was Ir oxide, which is metallic, possibly present as a capping layer. Moreover, observed turnover frequencies indicated that catalyst-support interactions were important in the cases of the sinter-resistant systems, an effect that may itself be linked to the phenomena that gave rise to materials with a strong resistance to nanoparticle sintering.