Effect Of Pretreatment Research Articles

Quantitative assessment of ash effects on densifying lignocellulosic biomass with chemicals followed by autoclave (DLCA) pretreatment

Ash in lignocellulose is critical in interfering biomass pretreatment. Densifying Lignocellulosic biomass with Chemicals followed by Autoclave (DLCA) is a novel and efficient pretreatment method, whereas the specific effects of ash on DLCA pretreatment remain unclear. Herein, we quantitatively investigated the impacts of ash contents on the pretreatment effectiveness, enzymatic digestibility, and fermentability of DLCA pretreated corn stover (DLCA-CS). With the ash contents increasing from 3.36 % to 9.50 %, the DLCA-CS with addition of sulfuric acid (sa) showed decreased pretreatment efficiency and enzymatic digestibility, whereas these characteristics of DLCA-CS with addition of calcium hydroxide (ch) were improved with increasing ash contents. Further pH measurement during the biomass pretreatment revealed that the anions involved in ash neutralized the sulfuric acid, thus decreasing the pretreatment efficiency and enzymatic digestibility of DLCA(sa)-CS, while the anions can cooperated with the calcium hydroxide, thus increasing the pretreatment efficiency and enzymatic digestibility of DLCA(ch)-CS. The highest ethanol production of DLCA(sa)-CS (60.7 g/L) and DLCA(ch)-CS (66.5 g/L) at 25 % solid loading was achieved with a low ash content of 3.36 % without detoxification step. This study highlights the importance of controlling the ash contents for enhancing the efficiency of DLCA pretreatment.

Supercritical CO2 extraction increases the recovery levels of omega-3 fatty acids in Tetraselmis chuii extracts

Tetraselmis chuii is a microalgae marketed as ingredient meeting the acceptance criteria for novel foods established by the European Union and can be an important source of healthy fatty acids (FA). The aim of this research was to characterize the FA profile of T. chuii fractions obtained by supercritical carbon dioxide (SCCO2) extraction operating with two sequential co-solvents and to evaluate the effect of biomass pretreatment (freeze/thaw cycles followed by ultrasounds). T. chuii biomass was confirmed to be an important source of omega-3 FA, mainly due to the abundance of α-linolenic acid, and pre-treatment significantly improved the lipid yield. Other omega-3 FA, such as 16:3, 16:4, 18:4, 18:5, 20:3 and 20:5, were also detected in different proportions. When SCCO2 extraction of pretreated and un-pretreated T. chuii was compared with conventional solvent extraction, the nutritional quality indices of the extracts were improved by the use of SCCO2.

Effect of alkaline deep eutectic solvents pretreatment on CH4 yield from anaerobic digestion of corn stover

Deep eutectic solvents (DES), comprising hydrogen bond donors (HBD) and acceptors (HBA), are gaining prominence in biomass pretreatment due to their excellent lignin depolymerization capabilities. This study explored the impact of alkaline DES pretreatment, specifically focusing on CH4 yield from corn stover anaerobic digestion. Batch experiments were conducted to assess the influence of ethylene glycol (EG) concentration, pretreatment time, and organic loading rate (OLR) on CH4 yield. Results indicated that these factors markedly affected the cumulative CH4 yield. Subsequent optimization using Box-Behnken design (BBD) significantly enhanced the CH4 yield by 1.16 times, achieving the optimal conditions at 0.4 v/v EG concentration, 33.8 min of pretreatment, and 22.2 w/v OLR. Notably, DMER64 and Methanobacterium emerged as the dominant bacterial and archaeal communities, constituting 40.2 % and 71.9 % respectively. Spearman correlation analysis underscored that enhanced substrate accessibility fostered a hydrogen-based, CH4-producing synergistic metabolic pathway. Alkaline DES pretreatment notably resulted in 20.5 % of the carbon flow being directed to CH4, demonstrating its efficacy in converting corn stover into a viable clean energy source and mitigating the environmental impact of agricultural waste.

Impact of Ohmic Heating and Ultrasound Pretreatments on Oil Absorption and Other Quality Parameters of Fried Potato

Impact of Ohmic Heating and Ultrasound Pretreatments on Oil Absorption and Other Quality Parameters of Fried Potato

Effect of Scanning Electron Beam Pretreatment on Gas Carburization of 22CrMoH Gear Steel

22CrMoH was selected for the gear steel material in this work, and the temperature field change in the scanning electron beam was analyzed to determine the optimal scanning parameters and explored the effect of scanning electron beam pretreatment (Abbreviated as: SEBP) on gas-carburizing (GC) efficiency and organizational properties of gear steel. The results showed that the scanning electron beam caused the material to form a thermally deformed layer 110 μm thick, and it promoted the adsorption of carbon atoms on the surface and their inward diffusion. Under the same gas-carburizing conditions, the carburizing efficiency was improved, and the thickness of the carburized layer increased from 0.78 to 1.09 mm. Furthermore, the hardness of the GC specimens with the SEBP increased from 615 to 638 HV0.05 at 0.1 mm of the sample surface, whereas the hardness of the cross-sectional region decreased gradually, indicating that the scanning electron beam enhanced the adhesion between the carburized layer and matrix zone. A comparative analysis of the microstructures of the GC specimens with and without the SEBP showed that the carbide particles in the surface layer of the samples become smaller and that of volume fraction of residual austenite reduced in size. In terms of the mechanical properties, the surface friction coefficient decreased from 0.87 to 0.46 μ and the GC specimen with the SEBP had a higher cross-sectional hardness gradient. Its friction coefficient was reduced from approximately 0.8 to almost 0.45 μ, and the wear amount of the specimens with SEBP was 47.7% of that of the matrix specimens.

Effects of pretreatment on the recycling properties of birch holocellulose paper

Effects of pretreatment on the recycling properties of birch holocellulose paper

Pretreatment of lignocellulosic biomass for bioethanol production

This review surveys recent progress in pretreatment methods for enhancing bioethanol production from lignocellulosic biomass. Various pretreatment techniques, including physical, chemical, and biological approaches, are evaluated for their efficacy in breaking down biomass structure and improving enzymatic digestibility. Key parameters influencing pretreatment effectiveness and integration with downstream processes are discussed. The review highlights promising strategies and identifies areas for further research to optimize bioethanol production from lignocellulosic feedstocks.

Effects of Ibuprofen and Diclofenac Pre-Treatment on Viability and Apoptosis Processes in Human Dental Pulp Stem Cells.

Background and Objectives: Stem cell-based regeneration strategies have shown therapeutic efficacy in various fields of regenerative medicine. These include bone healing after bone augmentation, often complicated by pain, which is managed by using nonsteroidal anti-inflammatory drugs (NSAIDs). However, information is limited about how NSAIDs affect the therapeutic potential of stem cells. Materials and Methods: We investigated the effects of ibuprofen and diclofenac on the characteristics, morphology, and immunophenotype of human mesenchymal stromal cells isolated from the dental pulp (DPSCs) and cultured in vitro, as well as their effects on the expression of angiogenic growth factors (VEGFA and HGF) and selected genes in apoptosis signalling pathways (BAX, BAK, CASP3, CASP9, and BCL2). Results: Ibuprofen and diclofenac significantly reduced the viability of DPSCs, while the expression of mesenchymal stem cell surface markers was unaffected. Both ibuprofen and diclofenac treatment significantly upregulated the expression of HGF, while the expression of VEGFA remained unchanged. Ibuprofen significantly altered the expression of several apoptosis-related genes, including the upregulation of CASP9 and BCL2, with decreased CASP3 expression. BAK, CASP3, CASP9, and BCL2 expressions were significantly increased in the diclofenac-treated DPSCs, while no difference was demonstrated in BAX expression. Conclusions: Our results suggest that concomitant use of the NSAIDs ibuprofen or diclofenac with stem cell therapy may negatively impact cell viability and alter the expression of apoptosis-related genes, affecting the efficacy of stem cell therapy.

Minimally Invasive Semiconductor Laser Surgery Combined with 5-ALA Photodynamic Therapy for a Chronic Hyperplastic Candidiasis Patient Who Is Ineffective to Antifungal Therapy.

Background: Chronic hyperplastic candidiasis (CHC) is a chronic oral mucosal infection caused by Candida, which has potential for malignant transformation. Diagnosing CHC can be challenging due to its various manifestations. In addition, fungal treatments often prove to be ineffective, highlighting the urgent need for a new safe and efficient treatment approach. Given the potential of CHC to transform into malignancy, it is crucial to emphasize dynamic monitoring and follow-up after treatment. Objective: We attempted to investigate the effect of semiconductor laser pretreatment combined with 5-amino-levulinic acid (5-ALA) photodynamic therapy (PDT) for CHC. Methods: We presented the successful treatment of CHC with mild dysplasia in a 30-year-old man using semiconductor laser and 5-ALA PDT after antifungal therapy proved ineffective. Toluidine blue staining, autofluorescence imaging, and DNA image cytometry were combined to dynamically monitor the progress of the disease. Results: We have obtained positive outcomes with the use of laser combined with PDT treatment. The patients experienced only mild adverse reactions after the treatment, and there was no indication of recurrence or malignant transformation during the subsequent follow-up period, as observed through various auxiliary examinations. Conclusions: This case report suggests that semiconductor laser surgery combined with PDT could be a promising treatment option for patients with CHC who do not respond to antifungal therapy. In addition, the use of combined noninvasive examinations might provide a more accurate assessment of malignant transformation in patients with CHC.

Torrefaction and hydrothermal carbonization of waste from the paper industry: Effects of atmosphere choice and pretreatment with natural acidic reagent on fuel properties

The hydrothermal carbonization (HTC) and torrefaction of paper sludges and biological sludges from the paper industry were investigated and the effect of pretreatment of the samples with alcoholic vinegar was evaluated. The HTC was performed at two different reaction times, while the torrefaction took place at two different temperatures and two atmospheres. The gas analysis showed that the optimal torrefaction time for the N2 atmosphere can be determined by observing the CO2 content in the gas phase, which is not possible for the CO2 atmosphere. The TGA analysis showed that the choice of atmosphere influences further combustion, with samples torrefied at lower temperatures being more sensitive to it. The carbon (C) content in the thermally treated samples increases from 39.85 to 48.06 wt% for biological sludge and from 40.02 to 60.21 wt% for paper sludge. The H/C and O/C ratios decrease and approach the values of conventional fuels. The fuel ratio is higher for the torrefied samples. The higher heating value (HHV) increased from 17.4 to 21.4 MJ/kg for biological sludge and from 16.2 to 22.4 MJ/kg for paper sludge. Higher temperature and longer treatment time led to products with a higher HHV and a higher energy density. The highest energy yields were achieved during torrefaction at 250 °C, regardless of the atmosphere, with temperature and type of material having the greatest influence. Acidification of the samples or acidic media in the HTC affects the properties of the products by increasing the C content and HHV and affecting combustion.

Municipal sewage sludge dewatering performance enhancement by ultrasonic cavitation and advanced oxidation: A case study.

The number of published literature on the effect of ultrasonic cavitation and advanced oxidation pretreatment on the dewatering performance of anaerobically digested sludge is very limited. This study aims at determining the optimum operating conditions of large-scale filtering centrifuges in wastewater treatment plants. The optimum dose of hydrogen peroxide, ultrasonic power, ultrasonic duration, ultrasonic pulse and particle size distribution for improved dewatering performance were determined in this study. In addition, shear stress-shear rate and viscosity-shear rate rheograms were developed to show the rheological flow properties for varying ultrasonic power and treatment duration. Optimum sonication power, time, pulse and amplitude were determined to be 14 W, 1 min, 55/5 and 20%, respectively. At a pH of 6.8, the optimum concentration of hydrogen peroxide was found to be 43.5 g/L. The optimum hydrogen peroxide dose in the combined conditioning experiments was determined to be 500 mg/L at a pH of 3. Under these optimum conditions, capillary suction time was reduced significantly by 71.1%. This study helps to reduce polymer consumption and provides the optimum pretreatment and dewatering operating conditions, and better monitoring and control in the dewatering unit has significant impact in the overall economy of wastewater treatment plants.

Effect of Ultrasonic Pre-Treatment on the Reverse Flotation of Kaolinite From Bauxite

ABSTRACT Cationic reverse flotation of kaolinite from bauxite is an alternative to adequate high silica bauxites to the specifications of the Bayer process. However, the presence of clay minerals influences the slurries rheology decreasing the flotation performance. The objective of this work was to investigate the use of ultrasonic pre-treatment on kaolinite flotation and contrast it with the traditionally used chemical dispersant. Two bauxite samples were characterized in terms of chemical and mineralogical composition, as well as particle size distribution. Flotation was accomplished after conditioning with sodium polyacrylate and/or pre-treatment in ultrasound. Determinations of viscosity, sedimentation yield, and screening followed by the analysis of available alumina and reactive silica were also conducted. By increasing the concentration of solids to more than 20 wt.%, the slurry behavior changed from a Newtonian to a non-Newtonian behavior, the viscosity increased, and the flotation performance decreased. The use of chemical dispersant and ultrasonic pre-treatment increased the flotation performance. The ultrasound had a more marked effect in slurries with higher concentrations of solids. This result is related to the synergic effect of particle dispersion and reduction of the slime coating promoted by kaolinite onto gibbsite particles.

Protein and Polysaccharide Recovery from Shrimp Wastes by Natural Deep Eutectic Solvent Mediated Subcritical Water Hydrolysis for Biodegradable Film.

Environmental pollution is a significant problem due to the improper disposal of plastics and shrimp shells outdoors. Therefore, the synthesis of biodegradable film from waste materials is highly important. The novelty of this research lies in the extraction of protein hydrolysates and chitosan from shrimp shells, as well as the fabrication of biodegradable film from these materials. In this study, the composite films were produced using the solution casting method. Moreover, the combined effect of ultrasound pretreatments (UPT) and natural deep eutectic solvents (NADES) was investigated as extraction media, to determine their potential impact on shrimp waste subcritical water hydrolysis (SWH). Shrimp shells were submitted to UPT in NADES solution, followed by SWH at different temperatures ranging from 150 to 230°C under 3MPa for 20min. Then, the physiochemical properties and bioactivities of the hydrolysates were assessed to determine their suitability for use in biodegradable packaging films. Additionally, the physiochemical properties and bioactivities of the resulting hydrolysates were also analyzed. The highest amount of protein (391.96 ± 0.48mg BSA/g) was obtained at 190°C/UPT/NADES, and the average molecular size of the protein molecules was less than 1000Da with different kinds of peptide. Overall, combined UPT and SWH treatments yielded higher antioxidant activity levels than individual treatments. Finally, the application of composite films was evaluated by wrapping fish samples and assessing their lipid oxidation. The use of higher concentrations of protein hydrolysates significantly delayed changes in the samples, thereby demonstrating the film's applicability.

Sustainable wheat straw pretreatment process by self-produced and cyclical crude lactic acid

The purpose of this study was to investigate an environmentally friendly and recyclable pretreatment approach that would enhance the enzymatic digestibility of wheat straw. Wheat straw was pretreated using self-produced crude lactic acid obtained from enzymatic hydrolysate fermentation by Bacillus coagulans. Experimentally, crude lactic acid at low concentration could achieve a pretreatment effect comparable to that of commercial lactic acid. After pretreatment at 180 °C for 60 min with 2.0 % crude lactic acid, hemicellulose could be effectively separated and high recovery of cellulose was ensured, achieving cellulose recovery rate of 95.5 % and hemicellulose removal rate of 92.7 %. Excellent enzymatic hydrolysis was accomplished with a glucose yield of 99.7 %. Moreover, the crude lactic acid demonstrated acceptable pretreatment and enzymatic hydrolysis performance even after three repeated cycles. This not only effectively utilizes the pretreatment solution, but also offers insights into biomass pretreatment using other fermentable acids.

The effect of pretreatment on the adsorption efficiency of activated carbon

Activated carbon (AC) is a very diverse adsorbent material with high porosity, high surface area, and excellent performance in vapor phase adsorption. The pretreatment provides a guaranteed way for the efficient adsorption performance of AC, which can remove the impurities and improve the porosity of AC. In this study, the difference between acid pretreatment and alkali pretreatment of coconut shell carbon was systematically investigated. The effect of heating with stirring pretreatment and ultrasonic pretreatment after acid treatment were also researched. The Brunauer-Emmett-Teller (BET) specific surface area, the N2 saturation adsorption, and the porosity of AC by acid-ultrasonic pretreatment can reach 1094.30 m2g−1, 352.51 cm3 (STP) g−1, and 0.5453 cm3g−1, respectively, which are higher than that of acid-heating with stirring pretreatment and alkali-heating with stirring pretreatment. Combined with the Scanning Electron Microscope (SEM) and X-ray Photoelectron Spectroscopy (XPS) analysis data, AC by acid-ultrasonic pretreatment has a better microstructure and clearer aperture. Among the three methods of preprocessing, acid-ultrasonic pretreatment yields the most favorable results. This work provides a possible way for AC pretreatment.

The effect of pretreatments on the drying of persimmon with infrared energy

AbstractThe effects of various pretreatments, including edible coatings, on drying kinetics and some physical quality parameters of persimmon varieties (Fuyu and Rojo Brillante) and differences between varieties were investigated. The experiments were conducted at an infrared radiation intensity of 1210 W m−2 and air velocity (v) of 1.5 m s−1. Drying time differed depending on pretreatments and varieties. Pretreatments generally shortened the Fuyu variety's drying time and increased the Rojo Brillante variety's drying time. Lower specific energy consumption and higher diffusion coefficient values were recorded for the Rojo Brillante variety compared to the Fuyu. In terms of quality parameters, the Fuyu variety generally obtained lower values for shrinkage. Rehydration rate was higher for the Rojo Brillante variety. Total color change was lower in the Rojo Brillante variety. Based on the pretreatments applied, xanthan gum gave better results in terms of operational parameters. In terms of quality parameters, ascorbic acid had better results for rehydration rate and shrinkage. For total color change, better results were obtained in arabic gum pretreatment. As a result, when an evaluation is made regarding variety differences and pretreatments applied, the Rojo Brillante variety can be recommended for drying.Practical applicationsPersimmon is a popular fruit in appearance, flavor, and rich nutritional content. The high moisture and sugar content in the fruit increases spoilage in a short time, making it difficult to consume in all seasons. For this reason, different preservation methods are being investigated to extend the shelf life. Sun drying and other drying methods developed as an alternative to these methods have many disadvantages. Different pretreatments prevent the negativities that occur in other drying methods. Especially, edible coatings can increase product quality by preserving color and appearance as well as controlling mass transfer, flavor, and aroma losses. This study investigated the effects of various pretreatments, including edible coatings, on drying kinetics and some physical quality parameters of persimmon varieties, as well the differences between varieties. Based on variety differences and pretreatments applied, the Rojo Brillante variety can be recommended for drying in terms of both processing and drying characteristics.

Effect of thermal pretreatment and gastrointestinal digestion on the bioactivity of dry-cured ham bone enzymatic hydrolyzates

This study reports the effect of thermal pretreatment and the use of different commercial proteolytic enzymes (Protamex, Flavourzyme, Protana prime, and Alcalase) on the free amino acid content (FAA), peptide profile, and antioxidant, antidiabetic, antihypertensive, and anti-inflammatory potential (DPPH, FRAP, and ABTS assay, DPP-IV, ACE-I, and NEP inhibitory activities) of dry-cured ham bone hydrolyzates. The effect of in vitro digestion was also determined. Thermal pretreatment significantly increased the degree of hydrolysis, the FAA, and the DPP-IV and ACE-I inhibitory activities. The type of peptidase used was the most significant factor influencing antioxidant activity and neprilysin inhibitory activity. Protana prime hydrolyzates failed to inhibit DPP-IV and neprilysin enzymes and had low values of ACE-I inhibitory activity. After in vitro digestion, bioactivities kept constant in most cases or even increased in ACE-I inhibitory activity. Therefore, hydrolyzates from dry-cured ham bones could serve as a potential source of functional food ingredients for health benefits.

Effect of pretreatment and activation conditions on pore development of coal-based activated carbon

Abundant pore volume and appropriate pore configuration are two crucial characteristics of high-performance carbonaceous adsorbents and catalysts. In this study, influences of pre-treatments (e.g., breaking, sieving and ash removal by acid) and activation conditions (e.g., activation time) on pore parameters (including BET surface area, pore diameter and pore hierarchy degree) of resultant activated carbon were systematically investigated. In addition, the difference between conventional carbonization-activation (i.e., the two-step preparation method) and one-step activation in pore development of activated carbons was revealed. The sample prepared by a 120-minute one-step activation exhibited a BET surface area high to 1038.1 m2/g and a pore hierarchy at 50.7 %. Based on the kinetics analysis using TGA reactor, reaction between the activator (i.e., CO2) and carbon matrix was enhanced in one-step activation, contributing to the generation of mesopores. Remarkably, a new indicator, Effective Activation Rate (EAR) was proposed to accurately describe the activation rate in one-step synthesis after decoupling the release of moisture and volatile compounds. The above conclusions provide guidance for flexibly regulating the pore configurations of activated carbons derived from natural precursors.

Landfill-mined soil-like fraction (LMSF) use in biopolymer composting: Material pre-treatment, bioaugmentation and agricultural prospects

Polylactic Acid (PLA) based compostable bioplastic films degrade under thermophilic composting conditions. The purpose of our study was to understand whether sample pre-treatment along with bioaugmentation of the degradation matrix could reduce the biodegradation time under a simulated composting environment. Sepcifically, we also explored whether the commercial composts could be replaced by landfill-mined soil-like fraction (LMSF) for the said application. The effect of pre-treatment on the material was analysed by tests like tensile strength analysis, hydrophobicity analysis, morphological analysis, thermal degradation profiling, etc. Subsequently, the degradation experiment was performed in a simulated composting environment following the ASTM D5338 standard, along with bioaugmentation in selected experimental setups. When the novel approach of material pre-treatment and bioaugmentation were applied in combination, the time necessary for 90% degradation was reduced by 27% using compost and by 23% using LMSF. Beyond the improvement in degradation rate, the water holding capacity increased significantly for the degradation matrices. With pH, C: N ratio and microbial diversity tested to be favourable through 16s metabarcoding studies, material pre-treatment and bioaugmentation allow LMSF to not only replace commercial compost in polymer degradation but also find immense application in the agricultural sector of drought-affected areas (for better water retention) after it has been used for PLA degradation.

Comprehensive recycling of slag from the smelting of spent automotive catalysts

Spent automotive catalyst is a valuable source of platinum group metals (PGMs), making them crucial secondary resources. Currently, the main process for recovering PGMs from these catalysts is metal capture method. The smelting process would produce a significant amount of residual slags containing various components like SiO2, Al2O3, CaO, Fe2O3, Na2O, as well as high levels of heavy metals including Cr, Pb, and Ni. These slags are considered either solid waste or hazardous waste and usually disposed of in landfills, which can have detrimental effects on the environment. Furthermore, the smelting slags also contain approximately 2–5 % rare earth elements and trace amounts of precious metal elements. In this study, vacuum carbothermal reduction is employed to pretreat the smelting slags. This method not only successfully removes the heavy metal element lead, but also efficiently achieves the recovery of rare earths, and the enrichment of platinum group metals by mineral phase transformation of cerium-zirconium solid solution and in-situ iron capture. The lead removal rate exceeded 99 %, and the grade of precious metals in the enrichment process was approximately 12 times higher than the original material, with a recovery rate more than 90 %. The leaching rate of rare earths also increased from less than 50 % to more than 95 % after vacuum carbothermal reduction. The effect of vacuum carbothermal reduction pretreatment on the smelting slag phase was systematically studied, and the mechanism behind the increasing rare earth leaching rate due to this pretreatment was further analyzed.