Acid Pretreatment Process Research Articles

Efficient Production of Fermentable Sugars from Common Reed Biomass Through Hydrothermal and Citric Acid Pretreatment Processes

Efficient Production of Fermentable Sugars from Common Reed Biomass Through Hydrothermal and Citric Acid Pretreatment Processes

Organic solvent extraction and characterization of Antarctic krill protein with high crystallinity and high molecular weight

A novel extraction method of high-performance Antarctic krill protein (AKP) by organic solvent was proposed. The optimal parameters of the acid pretreatment process were determined by response surface methodology, and then the optimal process of the organic solvent method was determined by an orthogonal test. The effect of the organic solvent method on the hydrogen bond interaction, secondary structure, and molecular weight of AKP was studied by Fourier infrared spectroscopy, X-ray diffraction, and gel electrophoresis. The result showed that, compared with the AKP extracted by the alkaline solvent method, the AKP extracted by the organic solvent method had more intermolecular hydrogen bonds, more β-corner, higher crystallinity, and higher molecular weight. High-performance AKP broadens the application of AKP in biomedical materials.

High-performance poplar-polyethylene laminates based on microwave-assisted acetic acid pretreatment process with potential application in construction

High-performance poplar-polyethylene laminates based on microwave-assisted acetic acid pretreatment process with potential application in construction

Preparation of Taraxacum kok-saghyz Rubber and Biofuel Ethanol Simultaneously by the Yeast Fermentation Process.

Taraxacum kok-saghyz(TKS) rubber is considered the most ideal alternative source of natural rubber (NR). Extracting rubber from TKS with high quality, low cost, and low pollution is the basis of commercial development. The TKS roots were subjected to morphological observation and detailed compositional analysis. Scanning electron microscopy (SEM) images confirm that rubber filaments are physically entangled with plant tissues due to differences in molecular polarity. Compared with the traditional solvent TKS rubber extraction process, a new rubber extraction process developed in this study, namely, the microbial extraction (″ME″) process, is less harmful to the environment and lower in cost. The ″ME″ process is divided into three steps: dilute acid pretreatment process, enzyme degradation process, and fermentation process. After each step is completed, the purity of TKS rubber will gradually increase from 84.8% to 93.8 to 95.5%. The TKS rubber finally obtained fully meets the requirements of the traditional rubber industry, especially the tire industry. Besides, the yield of biofuel ethanol, a by-product of cellulose fermentation, reaches 2.05 g/100 g of TKS roots (dry weight), which can effectively reduce the production cost of TKS rubber. In the rubber extraction process, microorganisms have little effect on the quality of TKS rubber. The results show that the molecular weight and chemical structure of TKS rubber is very close to NR, so the ″ME″ process can be used as a new method for large-scale extraction of TKS rubber.

Selective saccharification of crude glycerol pretreated sugarcane bagasse via fast pyrolysis: Reaction kinetics and life cycle assessment

Saccharification is a pivotal step in the conversion of lignocellulose to biofuels and chemicals. In this study, crude glycerol derived from biodiesel production was used in pretreatment to facilitate efficient and clean pyrolytic saccharification of sugarcane bagasse. Delignification, demineralization, destruction of lignin-carbohydrate complex structure, and cellulose crystallinity improvement in crude glycerol pretreated biomass could enhance levoglucosan producing reactions against competitive reactions, and therefore facilitate a kinetically controlled pyrolysis with apparent activation energy increased by 2-fold. Accordingly, selective levoglucosan production (44.4%) was promoted by 6-fold whilst light oxygenates and lignin monomers were limited to <25% in bio-oil. Owing to the high-efficiency saccharification, life cycle assessment suggested that the environmental impacts of the integrated process were less than those of typical acid pretreatment and petroleum-based processes, especially on the acidification (8-fold less) and global warming potential. This study provides an environmentally benign approach to efficient biorefinery and waste management.

Detoxification Approaches of Bagasse Pith Hydrolysate Affecting Xylitol Production by Rhodotorula mucilaginosa.

In this study, the potential of bagasse pith (the waste of sugar and paper industry) was investigated for bio-xylitol production for the first time. Xylose-rich hydrolysate was prepared using 8% dilute sulfuric acid, at 120 °C for 90 min. Then, the acid-hydrolyzed solution was detoxified by individual overliming (OL), active carbon (AC), and their combination (OL+AC). The amounts of reducing sugars and inhibitors (furfural and hydroxyl methyl furfural) were measured after acid pre-treatment and detoxification process. Thereafter, xylitol was produced from detoxified hydrolysate by Rhodotorula mucilaginosa yeast. Results showed that after acid hydrolysis, the sugar yield was 20%. Detoxification by overliming and active carbon methods increased the reducing sugar content up to 65% and 36% and decreased the concentration of inhibitors to >90% and 16%, respectively. Also, combined detoxification caused an increase in the reducing sugar content (>73%) and a complete removal of inhibitors. The highest productivity of xylitol (0.366 g/g) by yeast was attained after the addition of 100 g/l non-detoxified xylose-rich hydrolysate into fermentation broth after 96 h, while the xylitol productivity enhanced to 0.496 g/g after adding the similar amount of xylose-rich hydrolysate detoxified by combined method (OL+AC2.5%).

Optimization and evaluation of a three-step pretreatment process for PCB microdrills

The traditional Murakami two-step and three-step acid pretreatment processes were introduced to reduce the negative impact of Co on the cemented carbide tools during deposition of the diamond coatings. However, treatment methods requiring a longer etching time and a higher etching solution concentration lead to the formation of pores and cavities on the surface of the substrate, which would damage the substrate and thus significantly decrease the fracture load of the tools, especially microdrills with a small edge diameter. In this study, the pretreatment process of microdrills is optimized based on the traditional three-step process. The surface morphologies and Co content of the microdrills after pretreatment are investigated via scanning electron microscopy and energy-dispersive spectroscopy. The effect of the pretreatment on the fracture toughness of the microdrills and the adhesion of the diamond coatings is evaluated. The results show that the surface microstructure and fracture load of the microdrills are inevitably damaged during the acid and Murakami etching processes. Furthermore, the adhesion of the diamond coating depends on the final step of the acid etching process. The optimized three-step process consists of first etching with an acid solution for 10 s, then etching with a Murakami solution for 4 min, and finally etching with the acid solution for 30 s. This process improves the pretreatment efficiency and coating adhesion without significantly reducing the fracture load of the microdrills.

Extraction of Cellulose from Sugarcane Bagasse Optimization and Characterization

In this study, cellulose was extracted from sugarcane bagasse (SCB) through a convenient five-step treatment, and procedures were performed. During the alkaline curing process of the extraction of cellulose, NaOH has a concentration of (0.5, 1.5, 2.75, and 4%) and the extraction time (15, 30, and 45 min) at a constant temperature of 120°C were taken as variables and perfectly optimized by response surface methodology (RSM) for cellulose with the highest product. The optimum conditions were found to be 2.75% NaOH, 120°C, and 45 min with a cellulose yield of 73.71 ± 0.67% cellulose, 17.22 ± 0.82% hemicellulose, and 9.07 ± 0.95% lignin. Though most of the lignin was eliminated during the alkaline and dilute acid pretreatment process, the remaining lignin was removed by a solution treatment of 4% NaOH, and 21.92% H2O2 at 121°C for 44.97 min where the cellulose yield was found as 89.75 ± 0.64%, hemicellulose was 6.15 ± 0.83%, and lignin was 2.65 ± 0.66%. Morphological analysis revealed that the average diameter of the cellulose was 12.06 µm. Thermal and XRD diffraction analysis showed that the cellulose is thermally stable and has a crystallinity index of 31.63%. FTIR spectra demonstrate that cellulose was successfully extracted due to the removal of noncellulose components.

Experimental investigation on the mass-transfer area in a pilot-scale column with divided-wall structured packing under ship motions

A structured-packing column plays a crucial role in the acid pretreatment process for floating liquefied-natural-gas platforms. In columns, gas–liquid mass-transfer area directly affects the integral gas absorption performance. In this paper, we report an experimental investigation on the mass-transfer area in a pilot-scale column with Mellapak 250X structured packing divided by walls. Using the NaOH-Air test system, we compare the mass-transfer area between the present column and a column with regular structured packing under varying liquid loads, gas velocities, and ship movements. A surprising discovery was that adding walls into structured packing obviously increased the mass-transfer area, thereby converting ship motions from detrimental to beneficial.

Insights into the Influence of Different Pre-Treatments on Physicochemical Properties of Nafion XL Membrane and Fuel Cell Performance.

Perfluorosulfonic acid (PFSA) polymers such as Nafion are the most frequently used Proton Exchange Membrane (PEM) in PEM fuel cells. Nafion XL is one of the most recently developed membranes designed to enhance performance by employing a mechanically reinforced layer in the architecture and a chemical stabilizer. The influence of the water and acid pre-treatment process on the physicochemical properties of Nafion XL membrane and Membrane Electrode Assembly (MEA) was investigated. The obtained results indicate that the pre-treated membranes have higher water uptake and dimensional swelling ratios, i.e., higher hydrophilicity, while the untreated membrane demonstrated a higher ionic exchange capacity. Furthermore, the conductivity of the acid pre-treated Nafion XL membrane was ~ 9.7% higher compared to the untreated membrane. Additionally, the maximum power densities obtained at 80 °C using acid pre-treatment were ~ 0.8 and 0.93 W/cm2 for re-cast Nafion and Nafion XL, respectively. However, the maximum generated powers for untreated membranes at the same condition were 0.36 and 0.66 W/cm2 for re-cast Nafion and Nafion XL, respectively. The overall results indicated that the PEM’s pre-treatment process is essential to enhance performance.

Modelling and prediction approach for engine performance and exhaust emission based on artificial intelligence of sterculia foetida biodiesel

Sterculia foetida derived biodiesel is a potential fuel for a diesel engine. The Sterculia foetida biodiesel required a pre-refining process called degumming and an acid pretreatment process before converting them to methyl ester using the transesterification process. This study blended fuel from Sterculia foetida biodiesel and diesel with different volume ratios (5% to 30% of biodiesel blend with 95% to 70% diesel fuel). Sterculia foetida biodiesel and blended fuels met the ASTM D6751 and EN 14214 standards. The blended fuel is examined to obtain its influences on the performance and emission when operating at a diesel engine (1300 rpm to 2400 rpm). From the outcome, the engine performance of the SFB5 blend shows better performance than diesel fuel in terms of BTE (28.84%) and BSFC (5.86%). Artificial neural networks and extreme learning machines were employed to predict engine performance and exhaust emissions. The developed models gave excellent results, where the coefficient of determination is more than 99% and 98% for BSFC and BTE, respectively. When the engine is operated with SFB5, there is a significant reduction in CO, HC, and smoke opacity emissions by 8.26%, 2.08%, and 3.08%, respectively, and at the same time, an increase in CO2 by 3.53% and NOX by 22.39%. The comparison is made with diesel fuel. The extreme learning machine modelling is powerful for predicting engine performance and exhaust emission compared to artificial neural networks in terms of prediction accuracy. Sterculia foetida biodiesel–diesel blends of 5% show its capability to replace diesel fuel by providing engine peak performance than diesel fuel.

해조류 바이오매스로부터 Lactic acid를 제조하는 방법에 관한 연구

With the spread of COVID-19 worldwide, non-face-to-face services have grown rapidly, but at the same time, the problem of plastic waste is getting worse. Accordingly, eco-friendly policies such as carbon neutrality and sustainable circular economy are being promoted worldwide. Due to the high demand for eco-friendly products, the packaging industry is trying to develop eco-friendly packaging materials using PLA and PBAT and create new business models. On the other hand, Ulva australis occurs in large quantities in the southern seas of Korea and off the coast of Jeju Island, causing marine environmental problems. In this study, lactic acid was produced through dilute acid pretreatment, enzymatic saccharification, and fermentation processes to utilize Ulva australis as a new alternative energy raw material. In general, seaweeds vary in carbohydrate content and sugar composition depending on the species, harvest location, and time. Seaweed is mainly composed of polysaccharides such as cellulose, alginate, mannan, and xylan, but does not contain lignin. It is difficult to expect high extraction yield of the complex polysaccharide constituting Ulva australis with only one process. However, the fusion process of dilute acid and enzymatic saccharification presented in this study can extract most of the sugars contained in Ulva australis. Therefore, the fusion process is considered to be able to expect high lactic acid production yield when a commercial-scale production process is established.

Dilute Acid Pretreatment And Enzymatic Hydrolysis Of Lignocellulosic Biomass For Butanol Production As Biofuel

Biobutanol is one of the promising biofuel for substituting gasoline. Biobutanol produced from biomass fermentation using solventogenic clostridia which are able to convert a wide range of carbon sources to fuels such as butanol. Therefore, lignocellosic biomass has great potential as fermentation substrate for biobutanol production. Lignocellosic biomass should be hydrolized before fermentation by a pretreatment process and enzymatic hydrolysis. The various lignocellulosic biomass pretreatment will infl uence in butanol production depending on fermentable sugars content. The objective of this research is to get potential lignocellulosic biomass using dilute acid pretreatment and enzymatic hydrolysis process for biobutanol production. Eight types of biomass from sugarcane bagasse, rice straw, rice husk, empty fruit bunch (EFB) of palm oil, corn cob, pulp waste, traditional market organic waste, and microalgae were used in this experiment. After hydrolysis, the high result of total fermentable sugars in corn cobs, bagasse, rice straw, and rice husk, shows good opportunity of these biomass to be used as fermentation feedstocks for biobutanol production. In addition, pulp waste, organic waste, and microalgae are prospective as raw material but require more appropriate treatment either for to break down the cellulose/hemicellulose or to enhance reducing sugar content. Fine milling and delignifi cation have no signifi cant effect on cellulosic biomass conversion into fermentable sugars. Therefore, the production cost can be reduced. In order to enhance the sugar content and reduce the formation of inhibitor product, it is necessary to examine dilute acid pretreatment variations and appropriate operating conditions of enzymatic hydrolysis process

Saccharification of acid-alkali pretreated sugarcane bagasse using immobilized enzymes from Phomopsis stipata.

The online version contains supplementary material available at 10.1007/s13205-021-03101-2.

Mechanistic Insights into Morphological and Chemical Changes During Benzenesulfonic Acid Pretreatment and Ssf Process for Ethanol Production

Mechanistic Insights into Morphological and Chemical Changes During Benzenesulfonic Acid Pretreatment and Ssf Process for Ethanol Production

Progress of plated metallization for industrial bifacial TOPCon silicon solar cells

AbstractIndustrial tunnel oxide and passivated contact (i‐TOPCon) solar cells were metallized at Fraunhofer ISE using ultrashort pulse laser ablation of the passivation layers for the subsequent Ni/Cu/Ag plating process. The solar cells feature a tunnel SiOx and n‐type doped polysilicon layer covered by a SiNx at the rear side, whereas the front side is made of a boron emitter passivated with a AlOx/SiNx stack. The reference i‐TOPCon solar cells screen‐printed at the supplier reach an efficiency of 23.46% measured by Fraunhofer ISE CalLab. The impact of the laser process on the implied open circuit voltage (iVoc) is characterized showing minor impact on the TOPCon side, while the emitter side reveals an increased iVoc loss due to laser damage. Loss analysis by simulating the plated solar cells points out the benefit of reducing the laser contact opening (LCO) area in terms of shading and contact recombination. Optimization of laser ablation and hydrofluoric acid (HF) pretreatment process result in Voc &gt; 700 mV and FF &gt; 82% leading to a mean efficiency 23.6% measured in‐house and a champion efficiency of 23.84% measured at Fraunhofer ISE CalLab thus outperforming the references by 0.4%abs.

Revalorization of sunflower stalk pith as feedstock for the coproduction of pectin and glucose using a two-step dilute acid pretreatment process

BackgroundSunflower stalk pith, residue from the processing of sunflower, is rich in pectin and cellulose, thereby acting as an economic raw material for the acquisition of these compounds. In order to increase the commercial value of sunflower processing industry, a two-step dilute sulfuric acid treatment process was conducted on spent sunflower stalk pith to obtain the value-added products, pectin and glucose.ResultsIn this study, pectin was firstly extracted under mild acid condition to avoid pectin degradation, which was conducted at 90 °C with a pH of 2.0 for 2 h, and ~0.14 g/g of pectin could be recovered. Then the remaining solids after pectin extraction were subjected to the reinforced treatment process with 0.75% H2SO4 at 150 °C for 30 min to further improve enzymatic hydrolysis efficiency. Moreover, by combining a fed-batch enzymatic hydrolysis strategy, a solid loading content of 16% was successfully achieved and the glucose titer reached 103.1 g/L with a yield of 83.6%.ConclusionFinally, ~140 g pectin and 260 g glucose were produced from 1 kg of raw sunflower stalk pith using the integrated biorefinery process. This work puts forward a two-step dilute acid pretreatment combined with enzymatic hydrolysis method to produce pectin and glucose from sunflower spent waste.

Techno-economic analysis of bioethanol preparation process via deep eutectic solvent pretreatment

This study conducted a techno-economic analysis of the biorefining process via deep eutectic solvent pretreatment. Rice straw was the feedstock to prepare main product bioethanol, and by-product lignin. The economic analysis model with sensitivity analysis based on Aspen Plus was applied to evaluate the commercial potential and the impact of critical parameters on the minimum ethanol selling price (MESP). Acidic DES showed better results in biomass refining. MESP based on choline chloride/urea pretreatment process was 3049.9 $/ton, while the choline chloride/lactic acid pretreatment was 2128.1 $/ton. The bioethanol yield was 0.21 t/t via choline chloride/lactic acid pretreatment process, which was higher than choline chloride/urea. In choline chloride/lactic acid pretreatment, sensitivity analysis showed that due to the enzymatic hydrolysis of cellulose conversion rate, acetone price, and lactic acid price, MESP was fluctuated by 23.4 %, 6.25 %, and 5.31 %, respectively. Combined heat and power part could reduce MESP. High solid loading pretreatment had a positive impact on cost reduction.

Ni-CaO dual function materials prepared by different synthetic modes for integrated CO2 capture and conversion

Dual-functional materials (DFMs) present broad prospects in CO2 capture and in-situ conversion to value-added products using renewable energy. Herein, we proposed and demonstrated three different synthetic modes for preparing Ni-CaO DFMs using carbide slag as calcium precursor. CO2 sorption and in-situ hydrogenation performance of the Ni-CaO DFMs was evaluated using a fixed-bed reactor. Results indicated that CO2 sorption capacity and CO productivity of the synthesized Ni-CaO DFMs depended on the synthetic modes. The desired Ni/CS-P30-C synthesized by acid pretreatment of carbide slag followed by citric acid complex exhibited a high CO2 sorption capacity (13.28 mmol/g DFMs) and a great CO productivity (5.12 mmol/g DFMs) under the isothermal testing temperature of 650 °C. The sample also showed stable CO2 uptake and CO productivity within 17 cycles. The good CO2 sorption and in-situ hydrogenation performance were associated with the better textural properties, smaller particle size and more uniform dispersion of Ni species, which were resulted from propionic acid pretreatment and citric acid complex processes. In addition, Ni-CaO pellet with high mechanical strength (2.88 MPa) and abrasion ability (weight loss of 2.36% after 3000 rotations). had also been prepared by the extrusion-spheronization method. The pelletization process adversely affected the CO2 sorption and in-situ hydrogenation performance, but the pellet exhibited good stability in cyclic operations.

Understanding the effects of different residual lignin fractions in acid-pretreated bamboo residues on its enzymatic digestibility

BackgroundDuring the dilute acid pretreatment process, the resulting pseudo-lignin and lignin droplets deposited on the surface of lignocellulose and inhibit the enzymatic digestibility of cellulose in lignocellulose. However, how these lignins interact with cellulase enzymes and then affect enzymatic hydrolysis is still unknown. In this work, different fractions of surface lignin (SL) obtained from dilute acid-pretreated bamboo residues (DAP-BR) were extracted by various organic reagents and the residual lignin in extracted DAP-BR was obtained by the milled wood lignin (MWL) method. All of the lignin fractions obtained from DAP-BR were used to investigate the mechanism for interaction between lignin and cellulase using surface plasmon resonance (SPR) technology to understand how they affect enzymatic hydrolysisResultsThe results showed that removing surface lignin significantly decreased the yield for enzymatic hydrolysis DAP-BR from 36.5% to 18.6%. The addition of MWL samples to Avicel inhibited its enzymatic hydrolysis, while different SL samples showed slight increases in enzymatic digestibility. Due to the higher molecular weight and hydrophobicity of MWL samples versus SL samples, a stronger affinity for MWL (KD = 6.8–24.7 nM) was found versus that of SL (KD = 39.4–52.6 nM) by SPR analysis. The affinity constants of all tested lignins exhibited good correlations (r > 0.6) with the effects on enzymatic digestibility of extracted DAP-BR and Avicel.ConclusionsThis work revealed that the surface lignin on DAP-BR is necessary for maintaining enzyme digestibility levels, and its removal has a negative impact on substrate digestibility.