Pretreatment Methods Research Articles

Simultaneous determination of pesticides, mycotoxins and ferulic acid in Angelica sinensis by GC/LC-Q-TOF/MS

In this study, a strong applicable method that could determine a total of 33 pesticides (54 compounds), 11 mycotoxins and functional components (ferulic acid) simultaneously in Angelica sinensis was developed. The compatibility of the sample pretreatment method for pesticides, mycotoxins, and functional components was improved by optimizing the acidity of extraction solvents, the sequence of ice bath and oscillation, the volumetric solution, and so on. The PRiME HLB SPE pretreatment method was chosen as the optimal one when comparing four pretreatment methods. Among the 65 contaminants, 38 of those determined by liquid chromatography and 41 of those by gas chromatography, which showed good linearity (R2 > 0.9801), 97 % of them had a limit of quantitation (LOQ) of lower than 0.02 mg kg-1. The recovery of all compounds were suited between 70 % to 120 % and the RSD were all lower than 20 % at the spiked levels of LOQ, 2 × LOQ, and 10 × LOQ. For ferulic acid, the LOQ was 50 ng/mL, and it showed good linearity (R2=0.9988) within the range of 0.5 to 10 μg/mL. The recovery and RSD were 98.1 %, and 3.2 % (n = 6), respectively. The simultaneous determination of cross-category compounds in a single sample preparation was obtained by the combination of SPE and GC/LC-Q-TOF/MS. Therefore, this study could not only shorten the time for data acquisition and data analysis, but also improve the experimental efficiency.

A comparative study of pulsed electric field, ultrasound, milling and soaking as pre-treatments for assistance in the extraction of polyphenols from willow bark (Salix alba)

White willow (Salix alba) has a long history of use as an herbal remedy for treating common pain and inflammation. Pre-treatment is a crucial step that assists the subsequent extraction process and may affect the extraction efficiency of polyphenols from plant materials. The objective of this work was to study the impact of pre-treatment methods on the hot water extraction of polyphenols from willow bark. Pulsed electric field (PEF) and ultrasound (US) pre-treatments were compared to commonly used pre-treatment methods, milling and soaking. All pre-treatments significantly increased the total phenolic content (TPC) and antioxidant activity (p < 0.05) in willow extracts. At a similar energy level, PEF with 400 pulses yielded a higher TPC (44.33mg GAE/g d.w.) and antioxidant activity (DPPH of 74.58mg AAE/g and FRAP of 186.41mmol TE/g) than US pre-treated samples, but a small increase in ultrasonic energy resulted in the highest TPC (46.20mg GAE/g d.w.) and antioxidant activity (DPPH of 76.18mg AAE/g and FRAP of 220.20mmol TE/g) of all the pre-treatments. Compared with PEF and US, milling (42.69mg GAE/g d.w.) and soaking (40.29mg GAE/g d.w.) were less effective in recovering polyphenols but they were comparable with PEF and US when employed at low energy levels. Overall results indicate emerging technologies PEF and US can be alternatives to milling to enhance the extractability of polyphenols and to reduce energy consumption. The obtained willow extracts were a rich source of polyphenols that could be used for food and pharmaceutical applications.

Recent advances in nanocellulose pretreatment routes, developments, applications and future prospects: A state-of-the-art review.

In a quest to find eco-friendly materials from renewable resources, researchers have focused on cellulose materials, which is the primary reinforcing component of plant cell walls. Nanocellulose is at the forefront of research due to its wide range of sources, biocompatibility, large surface area and tunable surface chemistry. It has gained considerable attention in various industries as a nano-reinforcement for polymer matrices due to its hierarchical structure (medical and healthcare, oil and gas, packaging, paper, board, composites, printed and flexible electronics, 3D printing, aerogels). In this paper, we have reviewed the recent advances in nanocellulose production, physical properties, structural characterization, surface modification strategies, pretreatment methods, applications, limitations and future directions. This review emphasizes the quantification of nanocellulose extraction and applications of the most prevalent areas of nanocellulose research. In view of its increasing and broader applications, the demand for nanocellulose is expected to increase in the future.

Recent advances in lung cancer organoid (tumoroid) research (Review).

Lung cancer is the most critical type of malignant tumor that threatens human health. Traditional preclinical models have certain defects; for example, they cannot accurately reflect the characteristics of lung cancer and their development is costly and time-consuming. Through self-organization, cancer stem cells (CSCs) generate cancer organoids that have a structure similar to that of lung cancer tissues, overcoming to some extent the aforementioned challenges, thus enabling them to have broader application prospects. Lung cancer organoid (LCO) development methods can be divided into three broad categories based on the source of cells, which include cell lines, patient-derived xenografts and patient tumor tissue/pleural effusion. There are 17 different methods that have been described for the development of LCOs. These methods can be further merged into six categories based on the source of cells, the pre-treatment method used, the composition of the medium and the culture scaffold. These categories are: i) CSCs induced by defined transcription factors; ii) suspension culture; iii) relative optimal culture medium; iv) suboptimal culture medium; v) mechanical digestion and suboptimal culture medium; and vi) hydrogel scaffold. In the current review, the advantages and disadvantages of each of the aforementioned methods are summarized, and references for supporting studies are cited.

Waste-to-Energy technologies for municipal solid waste management: Bibliometric review, life cycle assessment, and energy potential case study

Inadequate municipal solid waste (MSW) management threatens public health and the environment. The waste-to-energy (WtE) route allows the production of electricity, heat, and other valuable chemical products. WtE consists of incineration, gasification, pyrolysis, and some emerging technologies. This study applies the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to conduct a bibliometric analysis of WtE technologies for MSW management research. Scopus-indexed articles were examined between 1971 and 2023. Four periods were determined and analyzed in terms of their most significant results. In addition, the most pertinent journals, Waste Management, Chemosphere, and Waste Management & Research, were ranked first, second, and third, respectively. Moreover, the top contributor countries are one in America (the United States), three in Asia (China, Japan, and India), and five in Europe (Spain, Italy, Germany, Sweden, and the United Kingdom). Throughout a Life Cycle Assessment (LCA) case study, the environmental performance of gasification and incineration as relevant technologies for treating MSW were contrasted. Gasification excelled in seven environmental parameters, suggesting that developing strategies for MSW gasification on a commercial scale should prioritize this aspect. Finally, the energy potential was assessed, which provided valuable information on the societal benefits of WtE technologies in various sectors, such as education, health, and electromobility. Under their respective contexts, stakeholders should enhance MSW sorting policies, pretreatment methods, and emerging valorization options. Increasing global interest in WtE requires a social, environmental, and economic evaluation before implementation.

Comparative study of different pretreatment methods on peanut oil quality characteristics, anti-oxidation attributes, and phenolic compound compositions

The peanuts heat pretreatment is a crucial step for the following oil extraction, influencing both efficiency and oil quality. The present study investigated the effects of oven roasting (OR, 150 °C, 25 min), infrared ray roasting (IRR, 150 °C, 25 min), and microwave roasting (MR, 700 W, 5 min) on the quality characteristics, anti-oxidation attributes, and phenolic compound compositions of peanut oil. All pretreatment methods changed the physicochemical properties and bioactive compounds of peanut oil. Notably, IRR resulted in the highest oxidation induction index (9.25 h) and enhanced free radical scavenging activity, with increases of 55 % (2,2-diphenyl-1-picrylhydrazyl (DPPH)) and 121 % (2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS)) compared with the control. Furthermore, the free phenolics content (Free-P) increased significantly, particularly with IRR, which was increased 6.00 times. Correlation analysis indicated that Free-P was the primary contributor to the anti-oxidation attributes of peanut oil. The results can provide valuable insights for optimizing peanut oil processing technologies.

Extraction and Quality Control of Chitin and Chitosan from Shrimp (Vanami) Litophenause Vanamei Shells Wastes

Objective/Background: The biological value of chitin and chitosan obtained from shrimp, such as physiological compatibility, non-toxicity, bio digestibility, absorption and chelating capacity, depends on qualitative parameters that are directly related to raw material source. This study was carried out to investigate extraction and characterization of chitin and chitosan from shrimp Litophenause vanamei shells wastes. Methods: Chitin and chitosan was extracted and characterized from shrimp L. vanamei shells found in Iran, using conventional methods of pretreatment, demineralization, and deacetylation. In this study, commercial shrimp L. vanamei shell was used to extract chitin and chitosan. Results: The degree of deacetylation of shrimp chitosan (49%) is directly related to solubility of chitosan. Chitosan is considered to have excellent biological value with these qualitative parameters. The yield of shrimp chitosan was 13.96%. Conclusion: These results showed that use of shrimp shell waste to produce chitin and chitosan will have more economic and biological value along with reducing environmental pollution.

Enhanced biomass densification pretreatment using binary chemicals for efficient lignocellulosic valorization

Many effective pretreatment methods (such as dilute acid, dilute alkali, ionic liquids, etc.) have been developed for lignocellulose upgrading, but several defaults of low working mass, high sugar loss and extra cost of solid-liquid separation and water washing hinder their large-scale application in industry. Besides, the valorization of lignin-rich residue from pretreated biomass after hydrolysis or fermentation greatly contributes to the economy and sustainability of lignocellulosic biorefinery, which is usually underestimated. This study developed a densification pretreatment with binary chemicals (densifying lignocellulosic biomass with sulfuric acid (SA) and metal salt (MS) followed by autoclave treatment ((DLCA(SA-MS)), which was conducted under mild condition (121 °C) with a biomass working mass as high as 400 kg/m3. The DLCA(SA-MS) biomass achieved over 95% sugar retention, 90% enzymatic sugar conversion and a high concentration of fermentable sugar (212.3 g/L) with superior fermentability. Furthermore, bio-adsorbent derived from DLCA(SA-MS) biomass residue was highly adsorptive and suitable for dyeing wastewater treatment, providing a feasible and eco-friendly method for lignin-rich residue valorization. These findings indicated that DLCA(SA-MS) pretreatment enables the full-component utilization of biomass and boosts the economic viability of lignocellulosic biorefinery.

Clarifying the mechanism of peroxydisulfate and sulfite activated by Fe2+ for waste activated sludge pretreatment: Enhancement of dewaterabiliy, removal of antibiotic resistance genes and pathogenic microorganisms

The remarkable performance of SO4•— based advanced oxidation processes in improving waste activated sludge (WAS) dewatering has recently received considerable attention. However, its potential effect on the removal of emerging pollutants is often overlooked. In this study, two types of pretreatment methods (S2O82-/Fe2+ and SO32-/Fe2+) were employed to comprehensively evaluate their performance in improving the dewatering of WAS and the removal of antibiotic resistance genes (ARGs) and pathogenic microorganisms. At the optimal dosage of 1.2/1.5 mmol-S2O82-/Fe2+/g-VS, the capillary suction time reduction rate of WAS after S2O82-/Fe2+ was 1.8 times than that of SO32-/Fe2+. Notably, both S2O82-/Fe2+ and SO32-/Fe2+ could remove the 12 types of ARGs identified in WAS. Nonetheless, S2O82-/Fe2+ was more effective in removing ARGs, with a range of removal rate (0.96–2.17 log-units), and reduced the propagation and proliferation potential of residual ARGs. Furthermore, the coliforms content in WAS after S2O82-/Fe2+ decreased significantly with a minimum of 1.84 ± 0.24 log (MPN/g-TS) compared to SO32-/Fe2+. Further analysis indicated that the redistribution of bound extracellular polymeric substances (EPS) in WAS, especially the variations in protein, was the key factor affecting the dewaterability. In contrast to SO32-/Fe2+, the S2O82-/Fe2+ could quickly destroy the EPS structure to release bound water, accelerate the dissociation of WAS flocs, and cause cell lysis and DNA dissolution because of the continuous production and accumulation of SO4•— in the hostile conditions inside. Therefore, S2O82-/Fe2+ is an efficient, economical, and green method to improve WAS dewatering and the removal of pollutants.

Enhancing degradation of PLA-made rigid biodegradable plastics with non-thermal plasma treatment

This study evaluated the efficacy of Dielectric Barrier Discharge Non-Thermal Plasma (DDBD-NTP) as a pretreatment method to enhance the degradation of rigid biodegradable plastics (RBP) during composting, specifically focusing on polylactic acid (PLA) products such as drinking cups (CS) and spoon handles (SH). Using a Single-Factor-At-A-Time (SFAT) design, the impact of NTP parameters, including input voltage and treatment duration, on the physicochemical properties was evaluated, and the subsequent degradation rate of RBP was assessed by measuring the degree of disintegration in a home-scale composter. The filamentary discharge mode of the DDBD plasma system selectively altered the surface characteristics of RBP without significantly affecting their bulk properties. High-voltage treatments significantly increased surface roughness and accelerated degradation rates, while low-voltage and short-duration treatments enhanced oxidation, as indicated by the increased O/C ratio (85.5% for SH and 66.1% for CS), showing a non-linear response to plasma intensity. Furthermore, NTP treatment reduced water contact angles (up to a 39.79% reduction for SH and 82.65% for CS), indicating enhanced hydrophilicity. All NTP-treated samples demonstrated significantly higher degradation rates compared to both untreated and thermally treated counterparts. Notably, ‘high-voltage for short-duration’ treatments, such as CS-3 and SH-3, exhibited the highest degradation rates among the samples. CS-3 achieved complete disintegration (100%) within 20 days, markedly exceeding the 2% observed in untreated CS samples. Similarly, SH-3 reached 36% disintegration after 35 days, considerably surpassing the 9% seen in untreated SH samples. The findings indicate that NTP treatment is a viable and sustainable method to enhance the biodegradation of plastic waste.

Determination of multiple restricted and prohibited ingredients in hair dyes using a novel 3D stationary phase coupled with gas chromatography-mass spectrometry

Hair dyes (HDs) are mainly composed of various benzene series, amines, and phenolic compounds. These ingredients are well known to have allergenic, teratogenic, and carcinogenic properties. As such, the presence of these ingredients in HDs has received increased attention in recent years. At present, the applications of traditional analytical and detection methods and commercial chromatographic columns are limited by problems such as poor qualitative analysis and inaccurate quantification. Thus, the development of new analytical and detection technologies and stationary phases is an urgent endeavor. Moreover, HDs contain complex compounds and exhibit significant matrix interference. Hence, appropriate sample pretreatment methods are necessary to analyze HDs. In this study, the 3D nonpolar rigid structure of triptycene (TP) was combined with the polar flexible chains of polyethylene glycol (PEG) to design and synthesize a TP derivative, TP-PEG, as a stationary phase for chromatographic columns. The stationary phase enabled the expansion of the selection range for polar and nonpolar analytes. Subsequently, gas chromatography-mass spectrometry (GC-MS) was used to quantitatively analyze 22 ingredients in HDs. The experimental results demonstrated that analytes with different polarities exhibited sharp and symmetrical peak shapes on the stationary phase, and all 22 analytes achieved baseline separation on the chromatographic column. The 22 ingredients in HDs showed good linear relationships within their respective ranges, with correlation coefficients greater than 0.9985. The average recovery rates at three spiked levels were in the range of 89.2%-103.2%, and RSDs were less than 5%. Compared with traditional methods, the proposed method has higher efficiency and better accuracy, thus verifying the excellent separation performance of the new stationary phase and the effectiveness of the established GC-MS detection method. The findings indicated the applicability of the developed method to the detection and analysis of various compounds in HDs.

Understanding the fouling characteristics in ultrafiltration membrane for marine algae-laden seawater pretreatment: Focus on the role of algal extracellular organic matter

The increasing frequency and extent of harmful algal blooms (HABs) due to global warming and environmental pollution pose significant challenges to the ultrafiltration (UF)-seawater reverse osmosis (SWRO) desalination process. The UF process is a dominant pretreatment method to reduce HAB fouling potential in subsequent SWRO processes. Herein, we systematically evaluate the UF membrane fouling characteristics at different growth phases of HAB algae in terms of reversible/irreversible fouling and pinpoint the fouling mechanisms on UF membranes in the real seawater matrix. We employed Prorocentrum donghaiense as a model marine HAB specie to characterize algal derivatives, including extracellular organic matter (EOM) and granule particles. LC-OCD, MFIs, 3D-EEM, and GPC were used to analyze algae-derived matters. Results from the multiple fouling model revealed that algal solution in both stationary and decline phases exhibit severe membrane fouling, characterized by rapid cake layer formation, swift flux decline, and high membrane resistance. Soluble EOM (S-EOM) was the primary contributor to membrane fouling, linked to its elevated concentrations of dissolved organic matters, polysaccharides, proteins, and humic substances, which are predominantly hydrophobic. Additionally, granule particles mitigated organic membrane fouling, as evidenced by the smaller permeate volume required for S-EOM cake layer formation (<5 mL), resulting in a faster initial flux decline. These results revealed a shift in released organic matter from protein-centric to humic substance-centric during the transition from exponential growth to the decline phase, with correlation analysis further underscoring the substantial contribution of humic substances to membrane resistance. This research highlights the distinct UF membrane fouling characteristics at different marine algal growth stages, offering theoretical support for predicting and managing HABs.

Nondestructive Detection of Corky Disease in Symptomless 'Akizuki' Pears via Raman Spectroscopy.

'Akizuki' pear (Pyrus pyrifolia Nakai) corky disease is a physiological disease that strongly affects the fruit quality of 'Akizuki' pear and its economic value. In this study, Raman spectroscopy was employed to develop an early diagnosis model by integrating support vector machine (SVM), random forest (RF), gradient boosting decision tree (GBDT), extreme gradient boosting (XGBoost), and convolutional neural network (CNN) modeling techniques. The effects of various pretreatment methods and combinations of methods on modeling results were studied. The relative optimal index formula was utilized to identify the SG and SG+WT as the most effective preprocessing methods. Following the optimal preprocessing method, the performance of the majority of the models was markedly enhanced through the process of model reconditioning, among which XGBoost achieved 80% accuracy under SG+WT pretreatment, and F1 and kappa both performed best. The results show that RF, GBDT, and XGBoost are more sensitive to the pretreatment method, whereas SVM and CNN are more dependent on internal parameter tuning. The results of this study indicate that the early detection of Raman spectroscopy represents a novel approach for the nondestructive identification of asymptomatic 'Akizuki' pear corky disease, which is of paramount importance for the realization of large-scale detection across orchards.

Stepwise oxidation of refractory pyrite using persulfate for efficient leaching of gold and silver by an eco-friendly copper(II)-glycine-thiosulfate system

Chemical oxidation is a promising pretreatment method for refractory pyrite enclosure to enhance Au/Ag extraction. Here, persulfate was employed for stepwise oxidation of a refractory pyrite concentrate with encapsulated Au/Ag: (i) pyrite oxidation began with heating-activation persulfate, where hydroxyl radical (•OH) acted as the primary oxidative species for fast-dissolving pyrite into Fe ions; (ii) pyrite self-dissolved Fe ions were in-suit used as a moderate activator of persulfate to generate •OH for sustainable oxidizing pyrite at room temperature. Mineralogical studies have confirmed that oxidation of the sulfide enclosure (FeS2) significantly reduced the particle size of pyrite, accompanied by pores creation and an increase in specific surface area. The variation of microstructure liberated Au and Ag particles to lixiviants for extraction, significantly improving leaching efficiency in an eco-friendly copper(II)-glycine-thiosulfate system to 92.2 % for Au and 88.6 % for Ag, respectively. This work provides a promising process for separating precious metals from refractory pyrite.

Deconstruction Engineering of Lignocellulose Toward High-Plateau-Capacity Hard Carbon Anodes for Sodium-Ion Batteries.

Biomass-derived hard carbon is a promising anode material for commercial sodium-ion batteries due to its low cost, high capacity, and stable cycling performance. However, the intrinsic tight lignocellulosic structure in biomass hinders the formation of sufficient closed pores, limiting the specific capacity of obtained hard carbons. In this contribution, a mild, industrially mature pretreatment method is utilized to selectively regulate biomass components. The hard carbon with a rich closed pore structure is prepared by optimizing the appropriate ratio of biomass composition. Optimized etching conditions enhanced the closed pore volume of hard carbon from 0.15 to 0.26 cm3 g-1. Consequently, the engineered hard carbon exhibited excellent electrochemical performance, including a high reversible capacity of 346 mAh g-1 with a high plateau capacity of 254 mAh g⁻¹ at 50 mA g⁻¹, robust rate capability, and cycling stability. The optimized hard carbon shows an 88 mAh g⁻¹ increase in plateau capacity compared to hard carbon from directly carbonizing bamboo fibers. This mature approach provides an easy-to-operate industrial pathway for designing high-capacity biomass-based hard carbons for sodium-ion batteries.

Designing a biochar-based pretreatment method for distillery effluents entering constructed wetlands

Spent lees is an important distillation waste by-product created during whisky production, characterised by low pH and high dissolved copper (dissCu) content. Constructed wetland systems (CWs) are used in some Scotch whisky distilleries to treat spent lees prior to surface water discharge to prevent substantial environmental risks of spent lees in aquatic ecosystems, by buffering the acidic nature and decreasing the dissCu and organics content. However, as these wetland systems are biological communities (containing bacteria, fungi, plants, etc.), direct disposal of spent lees into CW ecosystems presents a challenge given its nature. This study investigates the efficacy of modified biochar (waste) sourced from whisky cask cooperage operations, as an effluent pretreatment method. The aim is to transform this raw biochar into NaOH-modified biochar, which will be capable of buffering the effluent pH and removing dissCu from spent lees before it enters CWs. To enhance raw biochar, NaOH modification and additional heat treatment were utilised which increased the alkalinity, heavy metal removal capacity and pH buffering potential. Experiments with 0.2% and 2% NaOH treated biochar demonstrated its treatment performance using a diverse range of spent lees samples with varying characteristics, including pH (4.1–4.4), dissCu concentrations (33.8–59.5 mg/L), and total organic carbon (685–754 mg/L). Column studies further supported the efficacy of the modified biochars, showing significant pH elevation and efficient dissCu removal (of 5.72 mg of Cu per g of biochar) when treating spent lees. This dissCu removal capacity compares favorably with other wood-derived biochars studied in the literature, which have reported between 2.75 and 7.44 mg/g. Surface characterisation techniques (EDX, XPS, FTIR, XRD) showed how the Cu ions microprecipitated on the modified biochar surface, validating its remediation potential. This study highlights the potential of biochar as a sustainable pretreatment solution for distillery effluents, paving the way for enhanced and more circular waste management practices within the Scotch whisky industry.

Production and optimization of biofuels from locally isolated algal biomass: Strategies for circular economy integration

In the present study, we investigated the potential of locally isolated algal strains as alternative energy sources for sustainable biofuel production. The focus of this study was to identify algal strains that are capable of accumulating oils rich in essential fatty acids. Algal samples were collected from different areas and 14 isolates were obtained. Among the various pretreatment methods tested, hydrothermal pretreatment using sulfuric acid at 95 °C yielded the best results, with sample IIB-14 containing more than 2% reducing sugars. These sugars were then used for fermentation with the S. cerevisiae strain, resulting in an ethanol concentration of 3.52% ± 0.2%. This holistic approach contributes to the development of low-cost and environmentally friendly alternatives to traditional energy sources. While algal biofuels offer a promising substitute for fossil fuels, further advancements are needed before they can be widely adopted in the fuel market. Among these, isolates IIB-8 and IIB-9 showed the highest oil yields of 22.84% and 24.69% (w/w), respectively. The specific environmental settings for optimal growth of these strains were determined, and the physicochemical parameters of the oils, including iodine value, viscosity, density, acid value, saponification value, unsaponifiable mass, and peroxide value, were analyzed. The transesterification of oils into fatty acid methyl esters (FAMEs) revealed the presence of significant amounts of fatty acids, including EPA, DHA, and linoleic acid. Moreover, the study also explored the potential of algal biomass for bioethanol production, addressing the sustainability concerns of renewable energy supplies. Hydrothermal pretreatment using sulfuric acid at 95 °C yielded the highest concentration of reducing sugars (>2%) in IIB-14. Sugar extracted from algal biomass was used for fermentation. The Saccharomyces cerevisiae strain used for the fermentation process yielded an ethanol concentration of 3.52% ± 0.2%. This holistic approach contributes to the development of low-cost and environment-friendly alternatives to renewable energy sources. Algal biofuels may offer a practical substitute for fossil fuels, but there is still a long way to go before they can enter the fuel market and are widely used.

Impacts of alkaline washing pretreatment on municipal solid waste incineration fly ash (MSWI FA) and resulting geopolymers

The safe disposal and utilization of municipal solid waste incineration fly ash (MSWI FA) has emerged as a crucial challenge, primarily due to elevated levels of heavy metals and chlorides. In this study, the influence of key factors in different pretreatment methods on the physicochemical properties of MSWI FA was analyzed, and the effects and mechanism of different pretreatment methods on the resulting geopolymers were studied. Under the conditions of a liquid-solid ratio (L/S) of 7 mL/g, a rotational speed of 500 r/min, and a stirring time of 20 min, the alkali washing with 1 mol/L NaOH solution exhibited better effect than water washing. The total content of chlorides and the content of soluble chloride in AFA (MSWI FA with alkali washing) were 1.53 % and 0.85 %, respectively. Alkali washing had a greater influence on the migration of heavy metals from MSWI FA to filtrate than water washing. Meanwhile, alkaline washing exhibited better effect in calcium retention and sulfur removal. The pretreatment process enhanced the gel formation in geopolymers, subsequently exerting a significant influence on the compressive strength and leaching concentration of heavy metals. Thermogravimetric analysis showed the bound water content in AG (8.46 %) was the greatest in all simples, indicating that exerted the most pronounced impact on the gel formation during geopolymerization. And, the lower ratio of Si-O-Na to Si-O-T in AG (0.20) indicated a longer geopolymeric chains, which explained the higher compressive strength of geopolymers during the initial curing period. This article provides a new pretreatment method to promote the resource utilization of MSWI FA.

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.

Rapid Lactic Acid Content Detection in Secondary Fermentation of Maize Silage Using Colorimetric Sensor Array Combined with Hyperspectral Imaging

Lactic acid content is a crucial indicator for evaluating maize silage quality, and its accurate detection is essential for ensuring product quality. In this study, a quantitative prediction model for the change of lactic acid content during the secondary fermentation of maize silage was constructed based on a colorimetric sensor array (CSA) combined with hyperspectral imaging. Volatile odor information from maize silage samples with different days of aerobic exposure was obtained using CSA and recorded by a hyperspectral imaging (HSI) system. Subsequently, the acquired spectral data were subjected to preprocessing through five distinct methods before being modeled using partial least squares regression (PLSR). The coronavirus herd immunity optimizer (CHIO) algorithm was introduced to screen three color-sensitive dyes that are more sensitive to changes in lactic acid content of maize silage. To minimize model redundancy, three algorithms, such as competitive adaptive reweighted sampling (CARS), were used to extract the characteristic wavelengths of the three dyes, and the combination of the characteristic wavelengths obtained by each algorithm was used as an input variable to build an analytical model for quantitative prediction of the lactic acid content by support vector regression (SVR). Moreover, two optimization algorithms, namely grid search (GS) and crested porcupine optimizer (CPO), were compared to determine their effectiveness in optimizing the parameters of the SVR model. The results showed that the prediction accuracy of the model can be significantly improved by choosing appropriate pretreatment methods for different color-sensitive dyes. The CARS-CPO-SVR model had better prediction, with a prediction set determination coefficient (RP2), root mean square error of prediction (RMSEP), and a ratio of performance to deviation (RPD) of 0.9617, 2.0057, and 5.1997, respectively. These comprehensive findings confirm the viability of integrating CSA with hyperspectral imaging to accurately quantify the lactic acid content in silage, providing a scientific and novel method for maize silage quality testing.