Common Pretreatment Methods Research Articles

Exploring Recent Advances in Lignocellulosic Biomass Waste Delignification Through the Combined Use of Eutectic Solvents and Intensification Techniques

Growing awareness of resource sustainability and waste management has driven the search for circular-economy solutions. Lignocellulosic biomass waste, the most abundant renewable carbon resource, offers green potential as an alternative to declining non-renewable fuels. However, due to its recalcitrant nature, it requires pre-processing to convert it into valuable products like energy and chemicals. Biorefineries play a key role in this process by promoting the integral use of biomass, by finding ways to utilize lignin, previously treated as waste. Common pretreatment methods are unsustainable, prompting research into eco-friendly solvents and advanced techniques like ultrasound- and microwave-assisted methods. Recent approaches have also explored the use of eutectic solvents, which, when combined with these intensification techniques, offer promising results. These green technologies improve delignification efficiency, which in turn improves the saccharification process, reduces solvent use, and minimizes environmental impact. Despite progress, challenges remain in making these methods economically viable and adaptable to diverse biomass types. This review article highlights recent advances in sustainable treatment technologies, including the combined use of eutectic solvents and process-intensification techniques, and the potential of the obtained lignin in various industrial applications. It also discusses future prospects for more environmentally friendly processes in biomass utilization.

Meta-Analisis Pengaruh Blansir terhadap Total Fenolik Buah dan Sayur

Blanching is the most common pretreatment method for fruits and vegetables to maintain product quality. Numerous studies revealed desirable impacts of the process to total phenolic content, while the others showed opposite results. In addition, some differences in the blanching condition such as methods and classification of fruits and vegetables were also known able to affect total phenolic content. This study aimed to analyze the effect of blanching on total phenolic content in vegetables and fruits through a meta-analysis approach. Study selection was conducted with a PRISMA method. There were 28 articles and 82 data used for meta-analysis. The data were analyzed by Hedges’d to calculate the effect size with confidence interval (CI) utilizing OpenMee software. The result showed that blanching demonstrated significant effects on the rise of total phenolic content (hedges’d[95% CI]: 0.782 [0.037 to 1.527]; p<0.05). Based on fruits and vegetables subgroups, the blanching significantly affected the increase of total phenolic content in leaves (hedges’d[95% CI]: 1.484 [0.185–2.782]) and fruits (hedges’d[95% CI]: 2.504 [0.153–4.854] compared to stems and stalks, fruits as vegetable, shoots and sprouts, pulse, and flowers. Meanwhile, in terms of blanching method subgroups, hot water blanching (hedges’d[95% CI]: 1.096 [0.234–1.959]) had significant effects on the rise of total phenolic content compared to steam blanching. Moreover, this meta-analysis was robust against publication bias.

Preliminary Study on the Treatment Efficiency of Pasteurized Lime Thermal Alkaline Hydrolysis for Excess Activated Sludge and Reduction of Tetracycline Resistance Genes

Thermal alkaline hydrolysis is a common pretreatment method for the utilization of excess activated sludge (EAS). Owing to strict environment laws and need for better energy utilization, new methods were developed in this study to improve the efficiency of pretreatment method. Direct thermal hydrolysis (TH), pasteurized thermal hydrolysis (PTH), and alkaline pasteurized thermal hydrolysis (PTH + CaO and PTH + NaOH) methods were used to treat EAS. Each method was compared and analyzed in terms of dissolution in ammonium nitrogen (NH4 + -N) and soluble COD (SCOD) in EAS. Furthermore, the removal of tetracycline resistance genes (TRGs) and class 1 transposon gene intI1 from EAS was investigated. The NH4 + -N and SCOD concentrations in EAS treated by PTH were 1.24 and 2.58 times higher than those of TH. However, the removal efficiency of total TRGs and intI1 between the groups was comparable. The SCOD concentration of the PTH + NaOH group was 4.37 times higher than that of the PTH group, and the removal efficiency of total TRGs was increased by 9.52% compared with that by PTH. The NH4 + -N and SCOD concentrations of the PTH + CaO group could reach 85.04% and 92.14% of the PTH + NaOH group, but the removal efficiency of total TRGs by PTH + CaO was 19.78% lower than that by PTH + NaOH. Thus, to reduce the financial cost in actual operation, lime (CaO) can be used instead of a strong alkali (NaOH), and pasteurized steam at 70°C instead of conventional high-temperature heating to treat EAS. This study provides a reference for the development of alkaline hydrolysis under moderate temperatures along with the removal of TRGs in EAS.

Biofuel Production from Seaweeds: A Comprehensive Review

Seaweeds represent a promising and sustainable feedstock for biofuel production which raises increasing research interests. Their high availability, easy fermentable composition, and good degradation potential make them a suitable candidate for alternating fossil fuels as an advantageous energy resource. This comprehensive review aims to summarize and discuss data from the literature on the biochemical composition of seaweeds and its potential for biomethane and biohydrogen production, as well as to investigate the effect of the common pretreatment methods. Satisfactory yields comparable to terrestrial biomass could be obtained through anaerobic digestion; concerning dark fermentation, the challenge remains to better define the operating conditions allowing a stable production of biohydrogen. Finally, we propose a potential energy production scheme with the seaweed found by the Caribbean Islands of Guadeloupe and Martinique, as well as current techno-economic challenges and future prospects. An annual energy potential of 66 GWh could be attained via a two-stage biohythane production process, this tends to be promising in terms of energetic valorization and coastal management.

Short ozonation for effective removal and detoxification of fermentation inhibitors resulting from thermal pretreatment

Common pretreatment methods for bioethanol production from lignocellulosic biomass are carried out under acidic conditions at high temperatures and result in formation of by-products, such as formic acid, levulinic acid, furfural and HMF (5-hydroxymethylfurfural). These by-products have an inhibitory effect on yeasts, reducing yeast growth and fermentation, and thus ethanol production. In this study, the inhibitory dose of these by-products was investigated along with the use of short ozonation as a means of their detoxification. When the effect of ozone was tested directly on yeasts (without inhibitors), they exhibited tolerance to ozone, suggesting the utilization of ozonation in simultaneous saccharification and fermentation. Fifteen minutes of ozonation removed over 90% of the inhibitory effect originating from 50 mM furfural, 50 mM formic acid, 25 mM HMF, and 100 mM levulinic acid. Thermal pretreatment and enzymatic hydrolysis of pine sawdust resulted in inhibition of microaerobic yeast growth. This inhibition was relieved after short ozonation; however, continuous ozonation has motivated further inhibition, suggesting the formation of additional inhibitory compounds. The results demonstrate the applicability of short ozonation as a practical approach for removing by-products’ inhibitory effects originating from thermal pretreatment of lignocellulosic waste.

Determination of Cellulose, Water, and N-Methylmorpholine N-Oxide during the Production of Lyocell by Attenuated Total Reflection (ATR) – Fourier Transform Infrared (FTIR) Spectroscopy

Attenuated total reflection (ATR) – Fourier transform infrared (FTIR) spectroscopy with the pretreatment of converting the absorption spectrum into angle spectrum (CASAS) and partial least squares (PLS) was employed to rapidly and simultaneously determine the ingredients of cellulose slurries and solutions during lyocell production. ATR was employed to rapidly and conveniently collect the spectra of the swollen slurries and viscous solutions during production. CASAS was used to eliminate the influence on modeling by the optical path differences due to uneven ingredient distributions in the samples. The PLS models for the cellulose, water, and N-methylmorpholine N-oxide (NMMO) concentrations of the cellulose slurry/solution were constructed using the raw spectra, pretreated spectra by CASAS, and common pretreatment methods, respectively. The results show that CASAS eliminates interferences due to the differences in optical path and improves the performance of PLS model for each analyte. The standard errors of prediction (SEP) of models using CASAS for cellulose, NMMO, and water concentration of cellulose slurry were 0.368, 0.196 and 0.171, while the values for the cellulose solution were 0.442, 0.353, and 0.066, respectively. The standard errors of prediction (SEPs) of CASAS models are significantly lower than the reproducibility requirement of the reference method, 0.5. The reported approach using ATR-FTIR spectroscopy combined with CASAS and PLS is rapid and accurate for determining the ingredients of the cellulose slurries and solutions and offers potential for identifying similar samples.

Anaerobic biohydrogen production from biodetoxified rice straw hydrolysate

Thermal acid hydrolysis is the most common pretreatment method used to deal with waste lignocellulosic biomass. However, furan derivatives (5‑hydroxy-methylfurfural (5-HMF) and furfural) are unavoidably produced and influence downstream biofuel production. Biological methods are superior to physical and chemical methods in detoxifying 5-HMF and furfural because of economic concerns. Integrating the biodetoxification process into the lignocellulose pretreatment and downstream biofuel production procedure is an important issue. The previous novel strain Burkholderia cepacia H-2 capable of quickly degrading 5-HMF and furfural was applied in the biodetoxification process. In this study, the acid sorts and concentration effects on thermal acid rice straw hydrolysis were investigated first. Rice straw hydrolysates with various dilution ratios were then biodetoxified using on-site inoculating novel strain B. cepacia H-2. The biodetoxified rice straw hydrolysate was then used for biohydrogen production using dark fermentation. The highest hydrolysis efficiency and reducing sugar were 49% and 15.6 g/L, respectively when applying 0.5 M HCl to deal with 5% rice straw at 121°C for 15 min. The 5-HMF and furfural in the 2-fold diluted rice straw hydrolysate could be completely biodetoxified within 12 hrs. The hydrolysate hydrogen yields with and without biodetoxification were 0.90 and 0.64 mmol H2/mmol sugar, respectively. The biodetoxification process using the novel strain B. cepacia H-2 was successfully established and could be integrated into the lignocellulose pretreatment and downstream biofuel production procedure as using the rice straw as the feedstock.

Development of a simple nanofiber-based solid phase extraction procedure coupled with high performance liquid chromatography analysis for the quantification of eight sedative-hypnotic drugs in human urine samples

In this study, a novel solid phase extraction (SPE) method based on nanofibers was established and applied to the extraction and purification of eight sedative-hypnotic medications (zaleplon, zolpidem and six benzodiazepines drugs) from urine samples. A clean-up cartridge was homemade and polystyrene nanofibers were spun and selected as the adsorption material. After the SPE procedure, the obtained extraction solution was analyzed by high performance liquid chromatography (HPLC). The nanofibers type, adsorbent amount and desorption conditions were the main factors affecting the extraction efficiency and were optimized in detail. Under the optimal conditions, good linearity was obtained in the range of 1–10 μg/mL with the correlation coefficients (r) above 0.99. The LOD of the 8 analytes were 0.2–0.4 μg/mL, and the LOQ were 0.4–1 μg/mL. The intra- and inter-day precision (RSD) values of this method were within the acceptable ranges of 1.3–15.2% and 3.7–15.0%, respectively. The recoveries determined for the eight compounds at the three concentration levels were in the range of 90.4–113.3%. These results showed that the home-made cartridge has an excellent extraction efficiency for the studied compounds. Compared to other common pretreatment method, the proposed method is simple and reliable.

Comparison of three common pre-treatment methods for the determination of lead contents by GFAAS in Chinese health-care wines

ABSTRACT Sample pre-treatment plays an important role in sample analysis, which directly affects the accuracy and reliability of the results. In this work we studied the influence of three common sample pre-treatment methods (direct injection, microwave digestion and wet digestion) on the determination of lead (Pb) content of Chinese health-care wines by graphite furnace atomic absorption spectrometry (GFAAS). Six different brands of Chinese health wines were selected for the research. After each Chinese health-care wine was digested by three digestion methods, GFAAS was used to detect the Pb content of the samples. For the selected six different health-care wines, the results showed that the Pb content obtained by GFAAS with different pre-treatment methods were different. Microwave digestion had the best recovery, and was proposed to be applied to the pre-treatment of many kinds of health-care wines, while the direct injection method might be suitable only for health-care wine with lesser amounts of ingredients such as sugar. In the practical work, due to the complexity of the base composition of Chinese health-care wines, currently there is no relevant standard analysis method for the pre-treatment of Chinese health wines. According to the accuracies of the three chosen common pre-treatment methods, it was proposed that microwave digestion might be more suitable as a standard digestion method for the determination of Pb in Chinese health-care wines. This work could provide theoretical support for the further establishment of a standard analytical method for the determination of lead and other (heavy) metal elements in Chinese health wines by GFAAS and other methods.

Effect of removal of organic material on stable isotope ratios in skeletal carbonate from taxonomic groups with complex mineralogies.

Stable oxygen and carbon isotope ratios are one of the most accurate ways of determining environmental changes in the past, which are used to predict future environmental change. Biogenic carbonates from marine organisms are the most common source of samples for stable isotope analysis. Before they are analyzed by mass spectrometry, any organic material is traditionally removed by one of three common pretreatment methods: roasting, bleaching, or with hydrogen peroxide at various strengths and durations. This study compares δ18 O and δ13 C values in a control with no pretreatment with those from five different pretreatment methods using conventional acid digestion mass spectrometry. The objectives are to: assess the impact of the most common pretreatment methods on δ18 O and δ13 C values from (1) taxonomically underrepresented groups in previous studies, and (2) those that precipitate a wide range of biomineralogies, in the debate of whether to pretreat or not to pretreat. We analyzed the following biomineralogically complex temperate marine organisms from southern New Zealand: four species of bryozoans, four species of molluscs, two species of arthropods, and one species each of annelid, red alga, brachiopod, and echinoderm (test plates and spines treated separately). These species precipitate aragonite, High-, Intermediate-, and/or Low-Mg calcite (LMC) in their skeletons. We used linear mixed statistical models to compare the effects of the pretreatments and mineralogical composition on their δ18 O and δ13 C values. Roasting was the most effective pretreatment for the removal of organic matter and light H2 O2 the least, but the former had corresponding impacts on isotope ratios. δ18 O values were not directly affected by wt% MgCO3 , but they were significantly affected by the interaction of roasting and wt% MgCO3 . This same negative effect of roasting on species with higher wt% MgCO3 occurred in δ13 C values, but it was much more pronounced in δ18 O values. Both H2 O2 pretreatments significantly and negatively affected δ18 O values at higher wt% MgCO3 . Neither bleaching pretreatment significantly affected δ18 O values. δ13 C values were most negatively affected in skeletons with high wt% MgCO3 . There was also a strong negative roasting effect and more so at higher wt% MgCO3 . Bleaching and H2 O2 did not significantly affect δ13 C values. Based on these results, and when using skeletal carbonate of complex mineralogies, we recommend considering the abandonment of pretreatment of biogenic carbonate for stable isotope analysis due to confounded results from previous studies, difficulties with preparation, and/or the absence of significant effects of organic material on isotope ratios. If pretreatment is necessary, avoid roasting especially at higher temperatures and durations, use minimal bleaching, and in general avoid using High-Mg calcite species in O and C stable isotope studies. If bleaching is used, clearly indicate the concentration and duration of exposure.

Fungal Pretreatment and Enzymatic Hydrolysis of Genetically-modified Populus trichocarpa

Fungal pretreatment of Populus trichocarpa wood genetically modified to reduce lignin and alter lignin chemistry is investigated for its effectiveness as an alternative to common pretreatment methods. The goal of this work is to improve biomass utilization for biofuel and biochemical applications by increasing sugar release. Sugar release after enzymatic hydrolysis was measured after various biomass pretreatments (including wood-rot fungus, hot water, and dilute acid). In the wildtype, and in constructs downregulated in PAL, 4CL, and C3H, the fungal pretreatment resulted in substantial improvements in sugar yields, up to 2.4-fold increase in glucose yield and 6-fold increase in xylose yield after enzymatic hydrolysis compared to the unpretreated control. However, the effects of fungal pretreatment were inconsistent, and in genetic lines down-regulated in 4CL, CCoAOMT, CAld5H, and C3H, fungal pretreatment yielded similar or decreased sugar release after enzymatic hydrolysis.

Fungal pretreatment and enzymatic hydrolysis of genetically-modified Populus trichocarpa

Fungal pretreatment of Populus trichocarpa wood genetically modified to reduce lignin and alter lignin chemistry is investigated for its effectiveness as an alternative to common pretreatment methods. The goal of this work is to improve biomass utilization for biofuel and biochemical applications by increasing sugar release. Sugar release after enzymatic hydrolysis was measured after various biomass pretreatments (including wood-rot fungus, hot water, and dilute acid). In the wildtype, and in constructs downregulated in PAL, 4CL, and C3H, the fungal pretreatment resulted in substantial improvements in sugar yields, up to 2.4-fold increase in glucose yield and 6-fold increase in xylose yield after enzymatic hydrolysis compared to the unpretreated control. However, the effects of fungal pretreatment were inconsistent, and in genetic lines down-regulated in 4CL, CCoAOMT, CAld5H, and C3H, fungal pretreatment yielded similar or decreased sugar release after enzymatic hydrolysis.

Effects of microorganism within organic matter on the mechanical behaviour of solidified municipal dredged mud

Municipal mud consists of organic matter naturally deposited in a microbial-rich environment, and its common pre-treatment in the laboratory is normally different from that in situ. In this study, an improved pre-loading method and the common pre-treatment method (by air or oven drying) were first applied to investigate the effect of microorganisms within organic matter on performance of the solidified soils. Results reveal that (i) Atterberg limits in the pre-loading method were higher than those in the drying method; (ii) the time-dependent strength became stable for the solidified soils pre-treated by the drying method, while strength decreased for the soils pre-treated by the pre-loading method; (iii) pH value of solidified soils by the pre-loading method decreased more significantly. After excluding the possible porosity influence on solidified soils, the effects of microorganisms within organic matter were investigated by microbial identification tests, including fluorescence detection and high-throughput sequencing. The pre-treatment procedure changed the vitality and diversity of microorganisms, leading to a rebalance between acid erosion and cement hydration during long-term curing. At the end, the long-term strength of the solidified municipal mud by the traditional pre-treatment method (by air or oven drying) could be overevaluated.

Effect of Water and Acid Pre-treatment on the Physicochemical Properties of Rice Husk for Silica Extraction

Rice husks are residue materials from rice milling. These materials are mostly discarded after obtaining the rice, however, numerous studies have found out that rice husks are an excellent renewable source of silica. Rice husks are generally turned into rice husk ash in order to extract the silica in the material. Prior to the combustion process, pre-treatment methods are usually done in order to minimize the impurities in the husks. Failure to remove these impurities lead to undesired properties of the extracted silica. As such, we investigate some common pre-treatment methods, namely water and acid (HCl) treatment, and their effects on the surface morphology and elemental composition of the husks after treatment. It was found that H2O was more effective in removing the bromide ions Br−, while HCl becomes less effective at increasing concentration. Also, acid treatment was more effective in removing the sodium and potassium components compared to water treatment. However, efficiency decreases as the acid concentration increases due to interference of silica polymerization. Thus, for the removal of impurities in rice husk, lower concentration of acid pre-treatment is recommended.

Selection of characteristic wavelengths using SPA for laser induced fluorescence spectroscopy of mine water inrush.

In the process of prevention and control of water inrush disaster, it is of great significance to identify the type of water inrush source for coal mine safety production accurately and quickly. The application of laser induced fluorescence (LIF) technology to identify the water inrush in coal mine broke the shortage of the traditional hydrochemical method, which could realize the accurate and rapid identification of water inrush types. Firstly, in order to avoid the influence of random variations of spectral data, four kinds of common pretreatment methods were analyzed and compared, and the moving average smoothing method was chosen to preprocess the original fluorescence spectral data. Then, for the purpose of selecting the appropriate sample division method to improve the predictive performance of the model, four common sample division methods were compared, and the sample set partitioning based on joint x-y distance (SPXY) method was used to divide the samples into training set and test set. Further, the 10 characteristic wavelengths were selected by successive projections algorithm (SPA) to reduce the amount of data. Finally, the selected data was taken as input, the sigmoid function was selected as the activation function of extreme learning machine (ELM), and the number of hidden layer neurons was set to 34, which realized the construction of water source identification model. The prediction accuracy of ELM model for the training set and test set were 99.0% and 94.0%, respectively. In addition, the water samples collected at different time were mixed in the same way to form the independent verification set, and the prediction accuracy of the ELM water source identification model for independent verification set was 91.5%. The results shown that it was feasible to select the characteristic wavelengths of fluorescence spectra by using the SPA. The data of 10 characteristic wavelengths could fully represent the effective information of whole band spectrum. And it also provided a theoretical basis for the development of a special online identification instrument for mine water inrush.

Effect of Pretreatment on Allicin Degradation and Color Change in the Dehydration of Garlic

Abstract. Allicin is the most important active ingredient in garlic because it gives garlic its unique flavor and has a broad spectrum of antibiotic activities. It is also an indicator of garlic product quality. Color can also be used to determine the quality of dehydrated garlic. The allicin content and color of dried garlic are influenced by the processing method, such as pretreatment, and the drying parameters, primarily temperature. To explore the factors that affect the allicin content and color of dried garlic, this study compared the differences in allicin content and color for common pretreatment methods and drying temperatures (35°C for 22 h, 55°C for 12 h, and 75°C for 5 h, to simulate open-sun drying, solar drying, and factory drying, respectively). The results showed that high-temperature pretreatment had a negative effect on the color and allicin retention of dried garlic slices. Cold-water washing and 55°C drying temperature are recommended to produce good garlic color and preserve the allicin content (2.78 mg g-1) to meet both national and international standards. Keywords: Allicin, Color change, Dehydration, Drying, Garlic.

A Review of the Extraction and Determination Methods of Thirteen Essential Vitamins to the Human Body: An Update from 2010.

Vitamins are a class of essential nutrients in the body; thus, they play important roles in human health. The chemicals are involved in many physiological functions and both their lack and excess can put health at risk. Therefore, the establishment of methods for monitoring vitamin concentrations in different matrices is necessary. In this review, an updated overview of the main pretreatments and determination methods that have been used since 2010 is given. Ultrasonic assisted extraction, liquid–liquid extraction, solid phase extraction and dispersive liquid–liquid microextraction are the most common pretreatment methods, while the determination methods involve chromatography methods, electrophoretic methods, microbiological assays, immunoassays, biosensors and several other methods. Different pretreatments and determination methods are discussed.

Pilot-scale steam explosion pretreatment with 2-naphthol to overcome high softwood recalcitrance

BackgroundSteam explosion pretreatment has been examined in many studies for enhancing the enzymatic digestibility of lignocellulosic biomass and is currently the most common pretreatment method in commercial biorefineries. It is however not effective for overcoming the extremely high recalcitrance of softwood to biochemical conversion. Recent fundamental research in small-scale liquid hot water pretreatment has shown, though, that the addition of a carbocation scavenger like 2-naphthol can prevent lignin repolymerization and thus enhance the enzymatic digestibility of softwood cellulose. This work studies the technical application potential of this approach in a larger steam explosion pilot plant for surmounting softwood recalcitrance.ResultsThe addition of 35.36 g 2-naphthol to the steam explosion pretreatment of 1.5 kg spruce wood chips allowed to considerably enhance the enzymatic cellulose digestibility. Different ways of adding the solid 2-naphthol to steam pretreatment were tested. Mixing with the biomass before pretreatment could enhance digestibility by up to 55% compared to control experiments. Impregnation of the biomass with 2-naphthol was yet more effective. Acetone and ethanol were tested to dissolve 2-naphthol and impregnate the biomass. The solvents were then removed again by evaporation before the pretreatment. The impregnation allowed to enhance digestibility by up to 179 and 192%, respectively. A comparison to prevalent acid-catalyzed steam explosion pretreatments for softwood revealed that the scavenger approach allows for obtaining exceptionally high yields in enzymatic hydrolysis. The biomass impregnation with 2-naphthol even renders a complete enzymatic cellulose conversion possible, which is remarkable for a softwood pretreatment not removing lignin. Steam pretreatment experiments without explosive decompression revealed that the enhancing effects of the explosion and the scavenger complement each other well. The explosion enhances the accessibility of the cellulose while the use of the scavenger reduces particularly the deactivation of enzymes.ConclusionsThis is the first study to show that a carbocation scavenger in steam pretreatment can enhance the enzymatic digestibility of lignocellulosic biomass. The approach opens up a novel possibility for overcoming the high softwood recalcitrance in a process that does not require an acid catalyst or the removal of lignin from the biomass.

Pretreatment For Removal of Organic Material Is Not Necessary For X-Ray-Diffraction Determination of Mineralogy In Temperate Skeletal Carbonate

Abstract: Quantifying the effects of ocean acidification requires understanding the skeletal carbonate mineralogy in living marine organisms. X-ray diffractometry (XRD) is the simplest and most commonly used technique for determining this. Samples being analyzed by XRD are typically pretreated to remove organic material prior to grinding to a crystallite powder. This pretreatment was traditionally performed as organic material may obscure the mineral peaks on XRD traces. This study compared controls with no pretreatment with the most common pretreatment methods: roasting, immersion in chlorine bleach, and immersion in hydrogen peroxide. The latter two methods were performed at two strengths and two durations. We test the hypothesis that bleaching and/or roasting of skeletal carbonate to remove organic material does not affect the mineralogy of temperate skeletal carbonate at a scale detectable by XRD. This was done with biogenic skeletal carbonate from temperate marine environments around southern New Zealand. Specimens included 5 species of bivalve mollusks, 4 species of bryozoans, 2 species of barnacles, as well as 1 species each of serpulid worm, echinoid, gastropod mollusk, brachiopod, and coralline algae. Comparison to the untreated control showed that all pretreatments removed some organic matter and that the presence of organic matter in temperate skeletal carbonate does not affect the ability to qualitatively interpret mineralogy or semiquantitatively measure mineralogy using XRD. Given that pretreatment does not appear to be necessary and that some methods at least can cause unacceptable changes in mineralogy, we recommend that pretreatment for the removal of organic material be abandoned.

Techno‐economic analysis of cellulose dissolving ionic liquid pretreatment of lignocellulosic biomass for fermentable sugars production

Pretreatment of biomass is essential to produce fermentable sugars, which can be further transformed into biofuels. Most of the common pretreatment methods, including sulfuric acid pretreatment, lead to low sugar yields and high microbial inhibitors formation, and require an additional detoxification step prior to fermentation. Ionic liquid (IL) pretreatment has the potential to reduce or eliminate these problems, and, thus, recently, has gained significant attention as an alternative pretreatment technology. However, before commercial deployment, IL pretreatment requires a thorough assessment of its techno-economic feasibilities and bottlenecks. Thus, the main objective of this study was to assess the techno-economic feasibility of a commercial-scale IL pretreatment for a 113 million liter/year (30 million gal/year) cellulosic biorefinery and identify operational targets for process improvement. 1-ethyl-3-methylimidazolium acetate IL was used for analyses, which is one of the mostly investigated ILs and is currently best at dissolving the lignocellulosic biomass. Corn stover, poplar, and switchgrass were used as the model feedstock. Input data were obtained from recent literatures on IL pretreatment of these feedstocks. Estimated sugar production costs ($/kg) from corn stover, switchgrass and poplar were 2.7, 3.2, and 3.0, respectively. IL recovery was identified to be the most sensitive parameter followed by IL cost and heat recovery. Furthermore, for IL pretreatment to be economically competitive with sulfuric acid pretreatment, >97% IL recovery, ≤$1/kg IL cost, and >90% waste heat recovery are necessary, all of which are very optimistic considerations at the present state of technology, thus requires further research and development efforts. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd