Different Types Of Pretreatment Research Articles

DRY biorefineries: Multiscale modeling studies and innovative processing

Abstract This paper reviews studies on green resource fractionation for two different types of material displaying a lignocellulosic or granular-type structure or a composite of the two. It explains how the identification of specific biochemical or spectral markers helps monitor tissue fate along processing and thus increase our knowledge on material fractionation. The key role of tissue mechanical properties in fracture behavior and the value of characterizing them were highlighted to better understand particle composition and properties. The effect of different modes of mechanical stress and strain during grinding as the main step of fractionation was illustrated. The value of different types of pre-treatment before or at grinding to reduce energy required to fracture and enhance dissociation or compound accessibility was presented. Separation methods based on differences in properties of the generated particles, and particularly innovative developments based on electrostatic sorting, were reviewed.

Production of prebiotic-xylooligosaccharides from alkali pretreated mahogany and mango wood sawdust by using purified xylanase of Clostridium strain BOH3

Xylooligosaccharides (XOS) are emerging prebiotics which can be produced from lignocellulosic biomass including agro-residues and hardwood. In this study, we report the production of XOS from thermal-alkali pretreated hardwood such as mahogany and mango by using a purified xylanase from Clostridium strain BOH3. In the first approach, pure xylan is extracted from mahogany and mango hardwood and then the pure xylan is hydrolyzed by using the xylanase. In this case, 572 and 504mg XOS/g pure xylan were obtained from mahogany and mango woods, respectively. In the second approach, the same xylanase is employed to hydrolyze sawdust of hardwood after different types of pretreatments. After a thermal (121°C for 15min) pretreatment under a mild alkaline (0.05N NaOH) condition, the pretreated mahogany and mango sawdust can be utilized directly to produce 89.5 and 67.6mg XOS/g pretreated sawdust, respectively. XOS produced from the pretreated sawdust show strong prebiotic effects on Bifidobacteria and Lactobacilli. This report shows the possibility of producing XOS from pretreated woody wastes without using pure xylan as a substrate.

The influence of enzymatic treatment on antimicrobial properties of knitted fabrics dyed with plant extracts

In this paper the influence of different types of pretreatment (hydrogen peroxide and enzymes) on antimicrobial properties of knitted fabrics dyed with plant extracts of Achillea millefolium L. was examined. Three different cotton fabrics with different constructional characteristics and surface masses were used. Knitted fabrics were treated with methanolic plant extract (concentration 25 mg/mL) by using bath exhaustion method and subsequently treated with alginate. Antimicrobial properties of knitted fabrics treated with plant extract of Achillea millefolium L. on Escherichia coli, Staphylococcus aureus by using parallel streaking method (AATCC TM 147) were tested. In addition to antimicrobial properties testing, the mass loss of pretreated knitted fabrics, water retention value and color difference of pretreated and dyed knitted fabrics were also tested, depending on the type of applied pretreatment of knitted fabrics. It was found that the enzymatically treated knitted fabrics dyed with methanolic extract of the plant Achillea millefolium L. (concentration 25 mg/mL) and subsequently treated with alginate had better antimicrobial activity against Escherichia coli, compared to knitted fabrics treated with H2O2.

Influences of mechanical pretreatment on the non-biological treatment of municipal wastewater by forward osmosis

ABSTRACTMunicipal wastewater treatment involves mechanical, biological and chemical treatment steps for protecting the environment from adverse effects. The biological treatment step consumes the most energy and can create greenhouse gases. This study investigates municipal wastewater treatment without the biological treatment step, including the effects of different pretreatment configurations, for example, direct membrane filtration before forward osmosis. Forward osmosis was tested using raw wastewater and wastewater subjected to different types of mechanical pretreatment, for example, microsieving and microfiltration permeation, as a potential technology for municipal wastewater treatment. Forward osmosis was performed using Aquaporin Inside™ and Hydration Technologies Inc. (HTI) membranes with NaCl as the draw solution. Both types of forward osmosis membranes were tested in parallel for the different types of pretreated feed and evaluated in terms of water flux and solute rejection, that is, biochemical oxygen demand (BOD7) and total and soluble phosphorus contents. The Aquaporin and HTI membranes achieved a stable water flux with rejection rates of more than 96% for BOD7 and total and soluble phosphorus, regardless of the type of mechanical pretreated wastewater considered. This result indicates that forward osmosis membranes can tolerate exposure to municipal waste water and that the permeate can fulfil the Swedish discharge limits.

Effect of the Type of Pretreatment on the Uniaxial Compressive Strength of a Rock Core Sample

Uniaxial compressive strength measurements were made on different artificial rock core samples with different mineral compositions, particle size distributions, permeability, void ratio, and other parameters and subjected to different types of pretreatment. Poisson’s ratio and the elastic modulus of the samples were measured. It was established that the best method for preparing the sample for the measurements is to saturate with water under vacuum and then heat the oil and gas under pressure, simulating formation pressure.

Physical and chemical differences between one-stage and two-stage hydrothermal pretreated hardwood substrates for use in cellulosic ethanol production.

BackgroundThere are many different types of pretreatment carried out to prepare cellulosic substrates for fermentation. In this study, one- and two-stage hydrothermal pretreatment were carried out to determine their effects on subsequent fermentations. The two substrates were found to behave differently during fermentation. The two substrates were then characterized using physical and chemical parameters.ResultsThe one-stage substrate was found to have higher carbohydrate content and lower lignin content. It exhibited a higher level of viscosity, a larger settled volume, and a slower settling time than the two-stage substrate. It also showed higher polarity and reduced crystallinity. Glycome profiling showed physical differences between the two substrates, specifically pointing toward higher levels of pectin and hemicellulose in the one-stage substrate (MS1112) as compared to the two-stage substrate (MS1107).ConclusionsWe hypothesize that these physical and chemical differences between the substrates contribute to the differences seen during fermentation including: ethanol yield, ethanol titer, fermentation rate, fermentation completion time, mixing, and substrate solubilization. These findings can be used in optimizing pretreatment parameters to maximize ethanol conversion and overall process yield for hardwood substrates.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0446-9) contains supplementary material, which is available to authorized users.

Comparison of different types of pretreatment and enzymatic saccharification of Macrocystis pyrifera for the production of biofuel

In this work, the brown algae Macrocystis pyrifera were pretreated with dilute sulfuric acid, water and three different types of ionic liquids (ILs): 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), 1,5-diazabicyclo[4.3.0]non-5-ene acetate ([DBNH][OAc]) and 1,8-diazabicyclo-[5.4.0]–undec-7-ene–sulfurdioxide–monoethanolamine (DBU–MEA–SO2–SIL), to disassemble the complex polysaccharide structure. After each pretreatment procedure, enzymatic saccharification was performed to release the monosaccharides. The main building blocks of M. pyrifera were processed by derivatization via acid methanolysis and subjected to gas chromatographic analysis. It was found that the main constituents were alginate (60.6wt.%) and cellulose (22.6wt.%) of total carbohydrate content. The degradation of alginate requires the action of alginate lyase and oligoalginate lyase, which hydrolyze the main chain in a synergistic mechanism releasing uronic acid (unsaturated uronate). Upon saccharification of cellulose, cellulases and β-glucosidase were used allowing the release of glucose. It was found that the best pretreatment strategy for M. pyrifera consisted of a pretreatment with 2vol.% sulfuric acid, followed by saccharification of cellulose with a mixture of cellulases at pH5.2 for 4h at 50°C or by saccharification of alginate with the enzyme lyase/oligoalginate lyase at pH7.5 for 2h at 37°C. The process resulted in a release of 68.4wt.% of glucose (55.74±0.05mg glucose/g algae) whereas in the case of alginate 85.8wt.% of uronic acid (193.7±10.6mg uronic acid/g algae) was released. To the best of our knowledge this is the first time that saccharification of both cellulose and alginate from brown algae is reported.

Inoculum pre-treatment affects the fermentative activity of hydrogen-producing communities in the presence of 5-hydroxymethylfurfural

To enhance the productivity of mixed microbial cultures for fermentative bio-hydrogen production, chemical-physical pre-treatments of the original seed are needed to suppress the activity of hydrogen (H2)-consuming microbes. This approach might influence negatively the composition and diversity of the hydrogen-producing community with consequences on the functional stability of the H2-producing systems in case of perturbations. In this study, we aimed at investigating the effect of different types of pre-treatment on the performance of hydrogen production systems in the presence of an inhibitor, such as 5-hydroxymethylfurfural (HMF). The efficiency and the microbial community structure of batch reactors amended with HMF and inoculated with non-pretreated and pretreated (acid, heat shock, and aeration) anaerobic sludge were evaluated and compared with control systems. The type of pre-treatments influenced the microbial community assembly and activity in inhibited systems, with significant effect on the performance. Cumulative H2 production tests showed that the pre-aerated systems (control and HMF inhibited) were the most efficient, while the difference of the lag phase of the pre-acidified control and HMF-added test was negligible. Analyses of the structure of the enriched microbial community in the systems through PCR-denaturing gradient gel electrophoresis (DGGE) followed by band sequencing revealed that the differences in performance were mostly related to shifts in the metabolic pathways rather than in the predominant species. In conclusion, the findings suggest that the use of specific inoculum pre-treatment could contribute to regulate the metabolic activity of the fermentative H2-producing bacteria in order to enhance the bio-energy production.

Value added liquid products from waste biomass pyrolysis using pretreatments

Douglas fir wood, a forestry waste, was attempted to be converted into value added products by pretreatments followed by pyrolysis. Four different types of pretreatments were employed, namely, hot water treatment, torrefaction, sulphuric acid and ammonium phosphate doping. Subsequently, pyrolysis was done at 500°C and the resulting bio-oils were analysed for their chemical composition using Karl Fischer titration, thermogravimetry, ion exchange, and gas chromatography. Pretreatment with acid resulted in the highest yield of bio-oil (~60%). The acid and salt pretreatments were responsible for drastic reduction in the lignin oligomers and enhancement of water content in the pyrolytic liquid. The quantity of xylose/mannose reduced as a result of pretreatments. Although, the content of fermentable sugars remained similar across all the pretreatments, the yield of levoglucosan increased. Pretreatment of the biomass with acid yielded the highest amount of levoglucosan in the bio-oil (13.21%). The acid and salt pretreatments also elevated the amount of acetic acid in the bio-oils. Addition of acid and salt to the biomass altered the interaction of cellulose–lignin in the pyrolysis regime. Application of pretreatments should be based on the intended end use of the liquid product having a desired chemical composition.

Analysis of alkali ultrasonication pretreatment in bioethanol production from cotton gin trash using FT-IR spectroscopy and principal component analysis

Abstract Background Cotton gin trash (CGT) is a lignocellulosic residue that can be used in the production of cellulosic ethanol. In a previous research, the sequential use of ultrasonication, liquid hot water, and ligninolytic enzymes was selected as pretreatment for the production of ethanol from CGT. However, an increment in the ethanol production is necessary. To accomplish that, this research evaluated the effect of pretreating CGT using alkaline ultrasonication before a liquid hot water and ligninolytic enzymes pretreatments for ethanol production. Three NaOH concentrations (5%, 10%, and 15%) were employed for the alkaline ultrasonication. Additionally, this work is one of the first applications of Fourier transform infrared (FT-IR) spectrum and principal component analysis (PCA) as fast methodology to identify the differences in the biomass after different types of pretreatments. Results The three concentrations employed for the alkaline ultrasonication pretreatment produced ethanol yields and cellulose conversions higher than the experiment without NaOH. Furthermore, 15% NaOH concentration achieved twofold increment yield versus the treatment without NaOH. The FT-IR spectrum confirmed modifications in the CGT structure in the different pretreatments. PCA was helpful to determine differences between the pretreated and un-pretreated biomass and to evaluate how the CGT structure changed after each treatment. Conclusions The combination of alkali ultrasonication hydrolysis, liquid hot water, and ligninolytic enzymes using 15% of NaOH improved 35% the ethanol yield compared with the original treatment. Additionally, we demonstrated the use of PCA to identify the modifications in the biomass structure after different types of pretreatments and conditions.

Oxytocin and social pretreatment have similar effects on processing of negative emotional faces in healthy adult males

Oxytocin has been shown to affect several aspects of human social cognition, including facial emotion processing. There is also evidence that social stimuli (such as eye-contact) can effectively modulate endogenous oxytocin levels. In the present study we directly tested whether intranasal oxytocin administration and pre-treatment with social stimuli had similar effects on face processing at the behavioral level. Subjects (N = 52 healthy adult males) were presented with a set of faces with expressions of different valence (negative, neutral, positive) following different types of pretreatment (oxytocin—OT or placebo—PL and social interaction—Soc or no social interaction—NSoc, N = 13 in each) and were asked to rate all faces for perceived emotion and trustworthiness. On the next day subjects' recognition memory was tested on a set of neutral faces and additionally they had to again rate each face for trustworthiness and emotion. Subjects in both the OT and the Soc pretreatment group (as compared to the PL and to the NSoc groups) gave higher emotion and trustworthiness scores for faces with negative emotional expression. Moreover, 24 h later, subjects in the OT and Soc groups (unlike in control groups) gave lower trustworthiness scores for previously negative faces, than for faces previously seen as emotionally neutral or positive. In sum these results provide the first direct evidence of the similar effects of intranasal oxytocin administration and social stimulation on the perception of negative facial emotions as well as on the delayed recall of negative emotional information.

Effects of mechanical pre-treatment on the biogas yield from ley crop silage

Previous studies on substrates for biogas production have shown that different types of pre-treatments make the material more accessible for microbial degradation by breaking down the complex structure of the organic material, thereby increasing their potential for gas production. In this paper, two different mechanical pre-treatment apparatus, i.e. a Grubben deflaker (Gd) and a Krima disperser (Kd), were tested in a full scale setup to evaluate their effects on ley crop silage. The treatments were investigated with regard to their effects on particle size, methane potential, capacity and energy balance. The results after 115days of incubation in a batch assay show that methane production increased by 59% and 43% respectively after grinding with Gd and Kd. In both treatments, 90% of the ley crop was ground to particles of less than 2mm and more than 50% of the sample was reduced to particles smaller than 0.125mm. The energy balance was positive for Gd and around the break-even point for Kd. Analysis of the setup showed that Kd had almost twice the capacity of the Gd. If installed in the co-digestion biogas plant Växtkraft in Västerås, Sweden, the Gd and Kd could increase annual biogas yields by 790MWh and 585MWh respectively.

Ni/YSZ anode – Effect of pre-treatments on cell degradation and microstructures

Anode supported (Ni/YSZ–YSZ–LSM/YSZ) solid oxide fuel cells were tested and the degradation over hundreds of hours was monitored and analyzed by impedance spectroscopy. Test conditions were chosen to focus on the Ni/YSZ anode degradation and all tests were operated at 750 °C, a current density of 0.75 A cm −2. Oxygen was supplied to the cathode and the anode inlet gas mixture had a high p(H 2O)/p(H 2) ratio of 0.4/0.6. Commercially available gasses were applied. The effect of different types of pre-treatments on the Ni/YSZ electrode degradation during subsequent fuel cell testing was investigated. Pre-treatments included operating at OCV (4% and 40% H 2O in H 2) prior to fuel cell testing, cleaning of the inlet H 2 gas at 700 °C and processing the anode half cell via multilayer tape casting. Analyses of impedance spectra showed that the increase in the charge transfer reaction resistance in the Ni/YSZ ( R Ni,TPB) was decreased to ¼ or less for the pre-treated and fuel cell tested cells when compared with a non-pre-treated reference tested cell; all operated at the same fuel cell test conditions. Scanning electron microscopy and image analyses for the non-pre-treated reference tested cell and selected pre-treated cells showed significant differences in the area fractions of percolating nickel both in the active anode and support layer.

Selective Growth of Carbon Nanotubes on Printed Fe3O4 Nanoparticles

For selective growth of Carbon Nanotubes (CNTs) or Carbon Nanofibres (CNFs) a print technique was used to distribute the catalyst on the substrate surface. Suspensions of Fe3O4 nano-particles (NPs) (~ 15-20 nm) in chloroform (CHCl3) were prepared and printed by a soft nano-imprinting lithography process (NIL) on quartz and silicon substrates. After printing and evaporation of the solvent the catalyst distribution on the substrate surfaces was investigated. After different types of pre-treatments the hot-filament CVD followed depositing nanotubes and nanofibres.

Adhesion study of pulsed laser deposited hydroxyapatite coating on laser surface nitrided titanium

Hydroxyapatite (HA) coatings were fabricated by pulsed laser deposition (PLD) on commercially pure titanium which had been subjected to different types of pre-treatment. These include: (i) 60-grit SiC grinding, (ii) 320-grit SiC grinding, (iii) 1-µm diamond paste mirror-finishing, (iv) etching with Knoll solution, and (v) laser surface nitriding followed by selective etching. The HA coatings were pulsed laser deposited at different water-vapor pressures to determine the optimal processing conditions. The nitrided-etched specimen exhibits a three dimensional TiN dendritic network which promotes the adhesion between HA coating and titanium substrate. Among the specimens with different pre-treatments, the adhesion strength of HA is the highest for the nitrided-etched specimen, reaching about twice that for the mirror-finished specimen. Thin-film X-ray diffraction shows a high degree of crystallinity for the PLD deposited HA. According to energy-dispersive X-ray analysis, the Ca/P ratio of the deposited HA reaches an approximate value of 1.7, similar to that of the HA target. Scanning-electron microscopy reveals that the deposited HA is about 4 μm in thickness. Growth of apatite was rapidly induced on the HA coated specimens when immersed in Hanks' solution for 4 days, indicating that the PLD HA coating is highly bone bioactive. This could be partly due to the high wettability of the PLD HA surface.

Effects of long-term soil amendment with sewage sludges on soil humic acid thermal and molecular properties

Sewage sludges are frequently used as soil amendments due to their high contents of organic matter and nutrients, particularly N and P. However, their effects upon the chemistry of soil humic acids, one of the main components of the soil organic matter, need to be more deeply studied in order to understand the relation between organic matter structure and beneficial soil properties. Two sewage sludges subjected to different types of pre-treatment (composted and thermally dried) with very different chemical compositions were applied for three consecutive years to an agricultural soil under long-term field study. Thermal analysis (TG–DTG–DTA) and solid-state 13C NMR spectroscopy were used to compare molecular and structural properties of humic acids isolated from sewage sludges, and to determine changes in amended soils. Thermally dried sewage sludge humic acids showed an important presence of alkyl and O/N-alkyl compounds (70%) while composted sludge humic acids comprised 50% aromatic and carbonyl carbon. In spite of important differences in the initial chemical and thermal properties of the two types of sewage sludges, the chemical and thermal properties of the soil humic acids were quite similar to one another after 3 years of amendment. Long-term application of both sewage sludges resulted in 80–90% enrichment in alkyl carbon and organic nitrogen contents of the soil humic acid fraction.

Development of Sample Pretreatment of Silk for Radiocarbon Dating

We have developed sample pretreatments for silk for radiocarbon dating. Characteristics of silk under different types of pretreatment were investigated, as well as the behavior of dye and possible contaminants. We found that dye could be removed completely, together with all other foreign materials bigger than 1.2 μm, using a glass microfiber filter after decomposition with 6N HCl. The decomposed proteins were concentrated using Centriprep® ultrafiltration concentrators with 3 different molecular weight cut-offs. By taking a molecular weight fraction—which selects for secondary structures of silk protein—14C dating of silk samples can be made more reliable. This study confirms that uniformly fractured polypeptide chains of silk provide an appropriate fraction for 14C age dating to select silk protein against dye particles and undecomposed foreign contaminants.

The removal of pathogens in surface-flow constructed wetlands and its implications for water reuse

Microbiological quality represents the biggest concern to the reuse of treated wastewater. This paper reports and discusses the results of an international survey on the removal of indicators of microbiological contamination in surface-flow constructed wetlands. Constructed wetlands consistently provide a reduction of 90-99% (1-2 log-removal) in the concentration of indicators such as coliform bacteria and faecal streptococci. This removal is found in wetlands treating water from different types of pretreatment (primary sedimentation, activated sludge, trickling filter, maturation ponds). On the other hand, when the influent is of high microbiological quality, wetlands act as sources of pathogenic contamination. The final water quality, however, is still compatible with medium to no-contact recreational activities and other final water uses. High variability in the effluent quality and seasonality might limit the opportunities for reuse. The role of constructed wetlands in different treatment schemes and the remaining open questions concerning removal mechanisms and reference pathogens are discussed.

Study of the deposition of cerium oxide by conversion on to aluminium alloys

This paper reports work aimed at finding an alternative treatment to chromate conversion coatings (CCC) that could meet all the requirements of industrial applications. A first step was made by carrying out the deposition of films of CeO 2·2H 2O on aluminium alloys in a few minutes at room temperature with or without a catalyst. Different types of pretreatment (acidic or alkaline) led to drastically different results. A model for the catalytic deposition mechanism is suggested which is consistent with scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) observations. The anticorrosive properties of these coatings were investigated by potentiokinetic curves measurements and by electrochemical impedance spectroscopy (EIS). Encouraging results were obtained though the performances still do not equal those of CCC. Some of the coating features (adhesion, sealing of the anodic sites, etc.) which should still be improved are highlighted.

The effect of heat, adsorption and mechanochemical treatments on stuck structure and adsorption properties of fumed silicas

The structural characteristics of fumed silicas synthesised under varied conditions and standard fumed silicas subjected to different types of pre-treatment, such as heating, suspending–ball-milling–drying, ball-milling of dry powder, and immobilisation of polymers, were studied using adsorption–desorption methods. Variations of preparation conditions and applied treatments influence the structure of finished samples in respect of both micropores and mesopores in primary particle swarms (aggregates, agglomerates) dependent on the treatment time nonlinearly. However, pre-treatments change the mesopore parameters of final adsorbents to a greater extent than those of micropores due to significant rearrangement of the primary particle agglomerates and gaps between aggregates. Application of the regularisation procedure to compute the pore size distributions using overall adsorption equation based on the combination of the Kelvin equation and the statistical adsorbed film thickness allows us to study the dependence of the structural characteristics of fumed silicas on treatment conditions in details.