Effect Of Thermal Pretreatment Research Articles

Effect of thermal pretreatments on the quality attributes and irradiation markers of sesame oil extracted from sesame seeds without and with gamma irradiation

This study comparatively studied the effects of three thermal pretreatment methods, i.e., wet-heat (WT), roasting (RT) and microwave (MT), on the quality attributes and irradiation markers of sesame oil obtained from sesame seeds without and with gamma irradiation. Results showed that gamma irradiation had negligible effect on the quality of sesame seeds and their extracted oils. The effects of thermal pretreatments on irradiated and non-irradiated sesame seeds and their oils were similar, little synergistic effects were observed. The RT-treated oils had more carotenoids, chlorophyll, total phenols, tocopherols, and heterocyclic volatiles content, as well as longer oxidation induction time, but darker color compared with their WT- and MT-treated counterparts. All oil samples had identical FTIR spectra. Eight radiolytic hydrocarbons were identified in the irradiated sesame oils. Thermal pretreatments reduced the content of radiolytic hydrocarbons, but did not significantly change their composition. Our study helps to identify products from irradiated sesame seeds.

Effect of thermal pretreatment on the reactivity of red mud valorized as aluminosilicate precursor for geopolymer production

Thermal pretreatment has proven to be an effective method to improve the reactivity of red mud to be valorized as an aluminosilicate precursor for geopolymer production. This approach offers the dual advantage of recovering caustic residue in red mud and encapsulating heavy metal, thus, achieving the transformation of red mud into a cleaner and value-added construction material. However, the inconsistent properties of red mud, including variations in chemical composition, particle size, and amorphous content pose challenges and can lead to instability in geopolymer as well as the effectiveness of thermal pretreatment, limiting the scalability of red mud valorization. Here in this study, thermal pretreatment was employed on five types of red mud from three refineries by calcining each red mud at 800 ○C for 2 h and its effect on the reactivity of each red mud was evaluated by comparing the performance of the resultant geopolymer. The results demonstrated a significant enhancing effect from thermal pretreatment, particularly noticeable at NaOH concentrations of 4 M and 8 M. This again highlighted the potential of thermal pretreatment in the conversion of red mud into construction material. However, amplified disparities between each thermal pretreated-red mud were also observed. To further address the challenges associated with thermal pretreatment variability, the dissolubility of reactive content from each thermal pretreated-red mud under alkali environments was quantified through alkali leaching tests and correlated to the mechanical properties of its resultant geopolymer. A strong negative correlation was observed between the concentration of Si, Al, and Fe from thermal pretreated-red mud and the mechanical properties of its resultant geopolymer. This correlation has the potential to facilitate quality control measures for thermal pretreated-red mud and its derived geopolymer, enabling better process optimization and consistency in geopolymer production.

Effect of Thermal Pre-treatment on Thermal Gradient Response of Granitic Rocks: Insights from Optical Microscopy and Digital Image Correlation

Effect of Thermal Pre-treatment on Thermal Gradient Response of Granitic Rocks: Insights from Optical Microscopy and Digital Image Correlation

Effect of thermal pretreatment and nanobubble addition water on methane production from cowpea hull anaerobic digestion

Effect of thermal pretreatment and nanobubble addition water on methane production from cowpea hull anaerobic digestion

Effects of thermal pretreatment and puffing medium variously modify the microstructure and quality of crisps obtained from two banana varieties

Fat-free crisp food products are garnering more attention from modern consumers. Hot air combined explosion puffing is one processing method that can produce a crisp food snack. Therefore, the influences of thermal pretreatment, banana variety, puffing medium, and puffing temperature upon the microstructural changes, drying time, specific energy consumption (SEC), and banana crisp qualities were studied. The banana slices, Namwa (NW) and Homtong (HT) varieties, were blanched with hot water (HW) then hot air-dried at 90 °C and combined with explosion puffing with either superheated steam (SS-puffing) or hot air (HA-puffing) from 170 to 190 °C for 2 min. The experimental results showed a stronger cellular structure and lower enzymatic activities for NW samples compared to the HT samples. This led to a harder texture, longer total drying time, and less browning for NW crisps. The cellular structure of HT was more disrupted than NW after HW pretreatment. Such modified structure characteristics caused a decrease in volume ratio and lower crispiness for HT products, whereas the NW crisp had increasing volume ratio and higher crispiness relative to the non-blanched crisps. Even though the blanching pretreatments retarded browning and improved color uniformity for both banana varieties, the process increased the total drying time and the SEC values of the drying process. By applying SS-puffing and raising the puffing temperature of blanched NW samples, higher puffed volume and crispier texture products were obtained. Additionally, the total drying time and the SEC value were also reduced. The SS-puffing also led to browner products for both NW and HT samples. Finally, the overall preference score was markedly higher for blanched NW crisp compared to blanched HT crisp; however, neither score exceeded that of commercial products.

Effect of thermal pretreatment on the two-stage extraction of aluminum, sulfur and potassium from a fine-quartz bearing alunite

The extraction of aluminum, sulfur, and potassium from an alunite ore (Ghazvin, Iran) was studied by roasting followed by two-stage alkaline leaching. In the roasting stage, the effects of several key parameters including temperature (520 to 620 °C), reaction time (30–150 min), particle size (0.075 to 10 mm), and furnace medium (with and without diesel fuel and with charcoal) were investigated on the leachability of sulfur and potassium by sodium carbonate and of aluminum by sodium hydroxide. The first leaching stage was carried out with sodium carbonate at a pulp density of 20% (w/w), a reaction time of 4 h, a particle size of less than 75 µm, a temperature of 95 °C and a ratio of sodium carbonate to alunite of 1.5:1. The highest extractions of sulfur and potassium (99.9 % for both elements) were obtained with the ore roasted at 620 °C, a particle size of 3 mm, and a roasting time of 90 min. The extractions were significantly increased by increasing the temperature and roasting time. The second stage of leaching was conducted at the temperature of 95 °C, leaching time of 6 h and the sodium hydroxide concentration of 5 M at 15 % pulp density. The highest aluminum extraction (95.3 %) was obtained by reductive roasting with charcoal at a temperature of 570 °C, a roasting time of 30 min, and a particle size of less than 3 mm. For potassium and sulfur extraction, increasing the roasting temperature, reaction time and diesel fuel addition (above 3%) resulted in a decrease in aluminum extraction, which was attributed to the conversion of the alumina phase to a stable phase. The results of this study show that alunite ore could be an interesting alternative for alumina production.

Enhanced Biogas Production from Thermophilic Anaerobic Digestion of Poultry Slaughterhouse Sludge: Effect of Thermal Pretreatment and Micronutrients Supplementation

Enhanced Biogas Production from Thermophilic Anaerobic Digestion of Poultry Slaughterhouse Sludge: Effect of Thermal Pretreatment and Micronutrients Supplementation

Effects of thermal pretreatment and biotin supplementation on the anaerobic digestion of pineapple (Ananas comosus) wastes, kinetics of methane production, and statistical analysis

The anaerobic digestion (AD) of pineapple wastes (PW) was employed to understand the effects of design parameters, namely thermal pretreatment (TP) temperature (X1) and reaction time (X2), and biotin concentration (X3), to methane production. Kinetic parameters were evaluated by utilizing sigmoidal growth functions, whereas modified Gompertz (MGM) and Logistic function (LF) best described the system among all batch assays. Principal components analysis (PCA) and Pearson correlation matrix were used to understand the correlation and relationship between the design parameters, evaluated kinetic parameters, methane yield (Y), and process performance parameters, wherein it was found that the significantly statistical correlations were Rm-A, λ-X1, A-Y, A-%VS reduction, A-%pH change, Rm-Y, Y-%VS reduction, Y-%pH change, and %VS reduction-%pH change. Furthermore, the cumulative methane production profile in all reactors showed an increase of 19.2–169.2 % in Y compared to the control, suggesting that TP and biotin supplementation were suitable for the optimization of Y from the AD of PW. The Y among all reactors followed the order of A0 <A1 <A2 <A4 <A7 <A3 <A5 <A8 <A6 wherein the lowest Y from pretreated PW was observed at A1 (77.6478 mL/gVS), while the highest was recorded at A6 (175.3053 mL/gVS). The ANOVA results demonstrated that the contribution of main and interaction parameters to Y (X3 >X1X3 >X2X3 >X1 >X2 >X1X2) were statistically significant (p < 0.05), and therefore relevant in the microbial syntrophies during the AD of PW. From the regression analysis, a surrogate mathematical model was constructed with a goodness of fit R2adj= 0.998. Herein, the optimum design conditions in the methane production from AD of PW were found to be X1 = 80ºC, X2 = 120 min, and X3 = 0.25 mg/L.

Effect of thermal pretreatments on biogas production and methane yield from anaerobic digestion of aquatic weed biomass Hydrilla verticillata

Effect of thermal pretreatments on biogas production and methane yield from anaerobic digestion of aquatic weed biomass Hydrilla verticillata

Efficient solvent-free hydrodeoxygenation of bio-lipids over bifunctional NiW catalyst: Manipulations of surface-active sites by thermal pretreatment

The effect of thermal pretreatment on the bifunctional NiW catalyst and its hydrodeoxygenation (HDO) performance on oleic acid were investigated. Increasing the calcination temperature (CT) not only led to the growth of NiW particles, but caused the migration of Ni to the surface that resulted in the segregation of W. The reduction temperature (RT) was also able to tune the catalyst surface composition. A lower RT (600 °C) led to a W-rich surface, while a higher one (700 °C) interestingly resulted in a Ni-rich surface. To this end, the ratio of surface-active sites, i.e., the partially reduced W species (Wδ+) to Ni0 ones (Wδ+/Ni0), was manipulated. The highest Wδ+/Ni0 ratio of 2.6 was reached at the CT and RT of 550 °C and 700 °C, respectively, which contributed to an impressively high solvent-free deoxygenation of 95.1% at only 300 °C. The deoxygenation rate (rdeoxy.) was much higher than that of the reported non-precious catalysts, even comparable to the precious ones. Additionally, a high catalyst durability was found on non-acid feedstocks like triglycerides, long-chain alcohols, etc., but an acidic substrate like oleic acid tended to leach the loaded metals that eventually lessened the HDO activity.

Influence of thermal pretreatments on dimensional change and humidity sensitivity of densified spruce and poplar wood

The effect of thermal pretreatments on the dimensional change and humidity sensitivity of densified spruce (Picea orientalis) and poplar (Populus nigra) wood were investigated. A thermal pretreatment was applied on the wood specimens at 140 °C, 160 °C, 180 °C, and 200 °C for 7 h and 9 h. Wood specimens were then compressed at ratios of 20 % and 40 % at a temperature of 150 °C. The results showed that spring-back and thickness swelling increased in all specimens (thermally pre-treated and untreated) depending on the increase in compression ratio. However, set-recovery was determined higher at 20 % compression ratio. The equilibrium moisture content values ​​of untreated specimens and thermally pre-treated specimens at low temperatures (140 ºC and 160 ºC) were found lower than uncompressed specimens. The impact of compression ratio on equilibrium moisture content was not clear. Thermal pretreatments significantly affected the dimensional stability and hygroscopicity of densified specimens (especially poplar wood). Depending on the increase in thermal pretreatment temperature and duration, spring-back, set-recovery and thickness swelling in wood specimens decreased up to 31 %, 67 % and 62 %, respectively. In addition, equilibrium moisture content and water absorption decreased with the increase in thermal pretreatment temperature and duration. Moreover, the thermal treatment temperature was more important than duration on the investigated properties.

Effects of thermal pretreatment and equivalence ratio on DME/$${\hbox {O}}_2$$/$${\hbox {O}}_3$$ detonations

Effects of thermal pretreatment and equivalence ratio on DME/$${\hbox {O}}_2$$/$${\hbox {O}}_3$$ detonations

Effect of Thermal Pretreatment on the Physiochemical Properties and Stability of Pumpkin Seed Milk

During the production of plant-based milk, thermal treatment of raw materials is an important processing method to improve the physicochemical and nutritional quality of the final products. The objective of this study was to examine the impact of thermal processing on the physiochemical properties and stability of pumpkin seed (Cucurbita pepo L.) milk. Raw pumpkin seeds were roasted at different temperatures (120 °C, 160 °C, and 200 °C), and then processed into milk using a high-pressure homogenizer. The study analyzed the microstructure, viscosity, particle size, physical stability, centrifugal stability, salt concentration, heat treatment, freeze-thaw cycle, and environment stress stability of the resulting pumpkin seed milk (PSM120, PSM160, PSM200). Our results showed that the microstructure of pumpkin seeds was loose and porous, forming a network structure because of roasting. As the roasting temperature increased, the particle size of pumpkin seed milk decreased, with PSM200 showing the smallest at 210.99 nm, while the viscosity and physical stability improved. No stratification was observed for PSM200 within 30 days. The centrifugal precipitation rate decreased, with PSM200 showing the lowest rate at 2.29%. At the same time, roasting enhanced the stability of the pumpkin seed milk in the changes in ion concentration, freeze-thaw, and heating treatment. The results of this study suggested that thermal processing was an important factor in improving the quality of pumpkin seed milk.

Biological pre-hydrolysis and thermal pretreatment applied for anaerobic digestion improvement: Kinetic study and statistical variable selection

In the present study, two pretreatment methods (thermal pretreatment and biological pre-hydrolysis) were suggested for food waste (FW) with the aim to enhance biomass conversion and biogas production by anaerobic. The effects of thermal pretreatment (TP), including TP at 60 °C and 80 °C for 60 min, and TP at 100 °C, 120 °C and 140 °C for 30 min, well as biological pre-hydrolysis (BPH) at 37 °C, 55 °C, 37 °C followed by 55 °C and 55 °C followed by 37 °C for 40 h on anaerobic digestion performance of FW were evaluated in batch tests. Results were compared with untreated FW. The BPH and TP caused an increase in the soluble chemical oxygen demand and hydrolysis efficiency. The methane yield (MY) increased from 371.17 mL CH4/g VS for untreated FW to 471.95 mL CH4/ g VS. The maximal MY was recorded for BPH at 37 °C for 20 h followed by 55 °C for 20 h. The pretreatments increased the biogas production rate and reduced the lag phase. The most influential variables on the methane yield were investigated using three statistical methods: Principal component analysis, Mutual Information and R-squared. The results allowed a good modeling of the methane yield and minimized the overfitting effect. For reproduction and solid contribution to the field, we have attached to our article all the necessary material to reproduce the same statistical work as in the paper body.

Effect of Thermal Pre-treatment and Anaerobic Co-Digestion of Sludge and Waste on Physical Characteristics and Total Organic Carbon Removal

Effect of Thermal Pre-treatment and Anaerobic Co-Digestion of Sludge and Waste on Physical Characteristics and Total Organic Carbon Removal

Biomethane production from Arachis hypogea shells: effect of thermal pretreatment on substrate structure and yield

Biomethane production from Arachis hypogea shells: effect of thermal pretreatment on substrate structure and yield

Effect of thermal pretreatment on porous structure of asphalt-based carbon

Effect of thermal pretreatment on porous structure of asphalt-based carbon

Effect of Thermal Pretreatment on the Kinetic Parameters of Anaerobic Digestion from Recycled Pulp and Paper Sludge

Effect of Thermal Pretreatment on the Kinetic Parameters of Anaerobic Digestion from Recycled Pulp and Paper Sludge

Optimization and system energy balance analysis of anaerobic co-digestion process of pretreated textile dyeing sludge and food waste

Anaerobic digestion treatment can transform textile dyeing sludge (TDS) to resources, but direct anaerobic digestion of TDS products only little biogas. In order to improve the effect of anaerobic digestion, pre-treatment and co-anaerobic digestion were performed in this study. Two pre-treatment methods, which are thermal pre-treatment and free nitrous acid (FNA) pre-treatment, were selected for comparison. Then, food waste (FW), as the co-digestion substance, co-digested with thermally pre-treated TDS to explored the optimized ratio of pre-treated TDS and FW. Results indicated that both the two pre-treatment methods have a certain solubilization effect on TDS, but the effect of thermal pre-treatment is better than that of FNA. The optimal mixing ratio of thermally pre-treated TD and FW is 1:1. The removal rates of soluble chemical oxygen demand and aromatic amines were the highest (75% and 64%, respectively). The cumulative methane yield reached 479.9 mL CH4/g VS, which was increased by 20–40% compared to others ratios and 66.6% to the TDS. Furthermore, system energy balance analysis was evaluated. Based on the dyeing wastewater treatment plant with a daily treatment capacity of 15000 t, electricity produced by biogas can completely satisfy the electric consumption of the wastewater treatment plant and the anaerobic co-digestion system with 57.69% and 41.78% for the respective. It was found that TDS can be reused resourcefully by the AcoD and costs can be significantly reduced.

Effect of Thermal Pretreatments on Phosphorylation of Corypha umbraculifera L. Stem Pith Starch: A Comparative Study Using Dry-Heat, Heat-Moisture and Autoclave Treatments.

Talipot starch, a non-conventional starch source with a high yield (76%) from the stem pith of talipot palm (Corypha umbraculifera L.) was subjected to three different thermal treatments (dry-heat, heat-moisture and autoclave treatments) prior to phosphorylation. Upon dual modification of starch with thermal treatments and phosphorylation, the phosphorous content and degree of crosslinking significantly increased (p ≤ 0.05) and was confirmed by the increased peak intensity of P=O and P–O–C stretching vibrations compared to phosphorylated talipot starch in the FT-IR spectrum. The highest degree of crosslinking (0.00418) was observed in the autoclave pretreated phosphorylated talipot starch sample. Thermal pretreatment remarkably changed the granule morphology by creating fissures and grooves. The amylose content and relative crystallinity of all phosphorylated talipot starches significantly decreased (p ≤ 0.05) due to crosslinking by the formation of phosphodiester bonds, reducing the swelling power of dual-modified starches. Among all modified starches, dry-heat pretreated phosphorylated starch gel showed an improved light transmittance value of 28.4%, indicating reduced retrogradation tendency. Pasting and rheological properties represented that the thermal pretreated phosphorylated starch formed stronger gels that improved thermal and shear resistance. Autoclave treatment before phosphorylation of talipot starch showed the highest resistant starch content of 48.08%.