Solid-liquid Ratio Research Articles

An environmentally friendly production method: The pectin and essential oil from the waste peel of juvenile pomelo (Citrus maxima ‘Shatian Yu’) were extracted simultaneously in one step with an acid-based deep eutectic solvent

In agricultural production, the juvenile pomelo (Citrus maxima ‘shatian Yu’) is sometimes disregarded, yet its peel is rich in pectin and essential oils. The following parameters were found to be ideal for the extraction of pectin and essential oil: pH of 5.75, a liquid-solid ratio of 4 mL/g, a microwave power of 560 W, and a 30-min irradiation period. The maximum production of pectin was 26.70% ± 1.35% and the greatest output of essential oil was 2.09% ± 0.11% under these circumstances, both exceeding the yields of traditional steam distillation. Utilizing gas chromatography-mass spectrometry, the constituents of the essential oil were identified. There were 62 chemicals were found in the oil that was prepared by combining eutectic solvent extraction with microwave assistance, which better conserved the biological activity of juvenile pomelo peel essential oil. Overall, this technique shows how effective and eco-friendly acid-based deep eutectic solvent microwave-assisted extraction can be as a solution for treating agricultural waste.

Radiation reduction modification of sp2 carbon-conjugated covalent organic frameworks for enhanced photocatalytic chromium(VI) removal

A sp2 carbon-conjugated covalent organic framework (BDATN) was modified through γ-ray radiation reduction and subsequent acidification with hydrochloric acid to yield a novel functional COF (named rBDATN-HCl) for Cr(VI) removal. The morphology and structure of rBDATN-HCl were analyzed and identified by SEM, FTIR, XRD and solid-state 13C NMR. It is found that the active functional groups, such as hydroxyl and amide, were introduced into BDATN after radiation reduction and acidification. The prepared rBDATN-HCl demonstrates a photocatalytic reduction removal rate of Cr(VI) above 99% after 60 min of illumination with a solid-liquid ratio of 0.5 mg/mL, showing outstanding performance, which is attributed to the increase of dispersibility and adsorption sites of rBDATN-HCl. In comparison to the cBDATN-HCl synthesized with chemical reduction, rBDATN-HCl exhibits a better photoreduction performance for Cr(VI), demonstrating the advantages of radiation preparation of rBDATN-HCl. It is expected that more functionalized sp2 carbon-conjugated COFs could be obtained by this radiation-induced reduction strategy.

Porous red mud ceramsite for aquatic phosphorus removal: Application in constructed wetlands

Red mud (RM) and spent oyster mushroom substrate (SOMS), by-products of industrial and agricultural production, can be recycled for polluted freshwater purification, bringing about a win-win situation. In this study, unacidified RM and RM acidified with oxalic acid (O-RM) and hydrochloric acid (H-RM), respectively, were mixed with SOMS to produce a porous ceramsite as a potential constructed wetlands (CWs) substrate. The results showed that the O-RM, H-RM, and RM ceramsites displayed fine compressive strengths of 7.75 ± 1.14, 8.40 ± 1.30, and 8.84 ± 0.69 MPa after calcining at 950 °C for 30 min, respectively. The phosphorus adsorption capacities of H-RM, O-RM, and RM ceramsite at a solid-liquid ratio of 25 g/L were 1.18 mg/g, 0.88 mg/g, and 1.06 mg/g, respectively. Toxicity release experiments showed that the ceramsites did not cause secondary environmental pollution, except for arsenic (ranging from 0.210 to 0.238 mg/L). The H-RM ceramsite was tested in a tidal flow-vertical flow CW (TF-VFCW) with Iris pseudacorus L. and Canna indica L plants. In the TF-VFCW, the average chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) removal rates were 81.01, 90.25, 66.90, and 77.32 %, respectively. Plant growth had less impact on COD and NH4-N removal but had greater limited TN and TP removal. Scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction analysis confirmed that acid pretreatment and the incorporation of SOMS significantly increased the surface and interior porous structures of the ceramsite and enhanced phosphate adsorption by the polyhydroxyl aluminum-iron complex ions. Bacteroides and Campylobacter used the energy produced during polyhydroxyalkanoic acid (PHA) catabolism to absorb phosphorus. Therefore, the synergistic effect of the substrate, plants, and microorganisms achieved the removal of phosphorus from CWs and offered effective and environmentally friendly recycling of RM and SOMS.

Killing three birds with one stone: A novel valorization strategy for comprehensive utilization of waste titanium gypsum

This study proposed a novel process of killing three birds with one stone for valorizing titanium gypsum, which benefits the reduction of CO2 emissions in cement industries, the production of vaterite CaCO3 as potential feedstock of construction materials, and the fabrication of adsorbent for wastewater treatment. The indirect carbonation process of titanium gypsum was optimized considering the extractant type, extractant concentration, liquid-solid ratio, and temperature. Under the optimal conditions of CH3COONH4 6 M, liquid-solid ratio 15, and temperature 60 °C, the weight loss of titanium gypsum reached 75.01 %. The carbonation efficiency was 97.28 %, and the vaterite CaCO3 was produced. The co-carbonization of leaching residue and waste peanut shell produced biochar-based adsorbent with good adsorption performance of organic pollutants. The removal rate of rhodamine B at 60 min was close to 100 %, while the adsorption capacity reached 468.26 mg/g. The adsorption mechanism was discussed based on adsorption kinetics, isotherms, and characterizations. The economic evaluation of the proposed process clarifies the feasibility of the valorization strategy of waste titanium gypsum.

Ultrasonic-Assisted Extraction of Phytochemicals Such as L-Tryptophan, Serotonin, and Melatonin from Tomatoes

Large amounts of byproducts are generated by the food processing industries in the 21st century including bioactive compounds such as polysaccharides, polyphenols, carotenoids, and dietary fiber. Due to a lack of sustainable extraction techniques, these processing wastes are regarded as having negligible value in comparison to processed fruit or vegetables. Conventional extraction has limitations in terms of time, energy, and solvent usage. In comparison with conventional methods of extraction, ultrasonic-assisted extraction can extract bioactive components in a short period, at low temperatures, and with less energy and solvent, as well as maintaining the functionality of the components. However, UAE-related variables such as frequency, power, duty cycle, temperature, time, solvent type, and liquid-solid ratio must be understood and optimized for each byproduct. This article provides the mechanism, concept, and factors that influence bioactive compound extraction, with a focus on tomatoes.

Recovery of Cu, Co, and Fe from Pyrite Cinder Based on Mineral Phase Reconstruction.

Pyrite cinder (PyC) containing polymetallics is difficult to use due to the low grade of metals and complex mineral phase composition, the low reutilized rate of which causes the wastage of resources. In this paper, a novel approach based on mineral phase reconstruction was proposed to recover Cu, Co, and Fe from PyC. A feasible reduction roasting process was developed for mineral phase reconstruction, followed by leaching with sulfuric acid to recover Cu and Co; finally, the leaching residue was separated by a magnetic tube to recover Fe. The maximum copper and cobalt extract rates of 86.15 and 79.61% were achieved respectively under the optimized conditions of reduction roasting for 30 min at 550 °C and 30% CO/N2 volume fraction, followed by leaching for 4 h at a liquid-solid ratio of 4:1 (mL/g), a mass concentration of 160 g/L sulfuric acid, and a temperature of 70 °C. The iron concentrate can be obtained with 63.08% Fe grade and 98.91% recovery rate by magnetic separation at a magnetic field strength of 28.26 kA/m. The mechanism analysis results of mineral phase reconstruction revealed that the primary copper sulfide in PyC was transformed into free copper oxide, combined copper oxide, and secondary copper sulfide without changing the valence state of copper by reduction roasting, resulting in a higher extraction rate of copper. Meanwhile, cobaltosic oxide and cobalt ferrite in PyC were transformed into cobalt sulfate and cobalt sulfide with the reduction of Co(III) to Co(II), improving the extraction rate of cobalt.

Analyzing the Diversion Effect of Debris Flow in Cross Channels Utilizing Two-Phase Flow Theory and the Principle of Energy Conservation

The movement process of debris flow in the complex roads system is important for risk evaluation and emergency rescue. This paper presents an in-depth study of the diversion effect of debris flow in cross channels, a common branching structure in both natural and engineered environments, especially in the field of urban debris flow prevention. A mathematical model is established based on the conservation of mass, momentum, and energy, and a solid–liquid two-phase motion equation for debris flow is derived from two-phase flow theory. A numerical solution method, combining the finite difference method and finite volume method, is employed to discretize and solve the equation. The model’s validity and effectiveness are confirmed through a numerical simulation of a typical engineering case and comparison with existing experimental data or theoretical results. This study reveals that debris flow at cross channels exhibits a diversion phenomenon, with some debris flow continuing downstream along the main channel and some diverting into the branch channel. The diversion rate, defined as the ratio of outlet flow to inlet flow of the branch channel, indicates the magnitude of this effect. This research shows that the solid–liquid ratio, inflow, width ratio, height ratio, and angle of the cross channel significantly impact the diversion effect. A series of numerical simulations are conducted by altering these parameters as well as the physical properties of debris flow and boundary conditions. These simulations analyze changes in flow rate, velocity, pressure, and other parameters of debris flow at cross channels, providing insights into the factors and mechanisms influencing the diversion effect. This research offers a robust instrument for comprehending and forecasting the dynamics of urban debris flows. It contributes significantly to mitigating the effects of debris flows on city infrastructure and enhancing the safety of city dwellers.

Strongly acidic lead contaminated soil solidification/stabilization using metakaolin-modified fly ash phosphoric-based geopolymer

The existing binders are difficult to be compatible with the acidic environment of acidic heavy metal contaminated soil, it is hard to repair acidic heavy metal contaminated soil. In this study, a modified acid phosphorus-based geopolymer (MAPG) binder suitable for the solidification/stabilization (S/S) treatment of acidic heavy metal Pb2+ contaminated soil was fabricated using aluminum dihydrogen phosphate (ADP) as activator, fly ash and metakaolin (MK) as raw materials. The influences of liquid–solid ratio (L/S), MK content, ADP concentration, curing age and leaching environment on the compressive strength, toxic leaching, resistivity, pH and EC of MAPG stabilized acidic Pb2+ contaminated soil were studied. Meantime, the X-ray diffraction, scanning electron microscopy, fourier transform infrared spectroscopy, and mercury intrusion (MIP) experiments were used to study the chemical properties and microscopic performance of MAPG treated acidic Pb2+ contaminated soil. The results showed that the MAPG binder prepared from MK had an excellent S/S effect on the acidic Pb2+ contaminated soil, and the MAPG binders had good compatibility with the acidic environment. The compressive strength of each group of MAPG stabilized soil could meet the strength standard (>350 kPa) for solid waste landfill and Pb2+ leaching concentration is < 5 mg/L for toxicity identification criteria after 7 days of curing. With an increase in curing age, the strength of stabilized acidic contaminated soil decreased slightly, but the strength still met the requirements of landfill strength standard after 28 days of curing. In three different leaching environments, the Pb2+ leaching decreased with an increase in curing age. Microscopic analysis showed that the main crystalline compounds in stabilized contaminated soil were potassium feldspar, Berlinite and lead phosphate compounds, and their contents were related to L/S, MK content, ADP concentration, and curing time. Potassium feldspar, berlinite, and lead phosphate compounds could not only fill pores, but also had physisorption, encapsulation and chemical precipitation effects on Pb2+. The study could provide an economical, environmental friendly and efficient binder for the remediation of acidic Pb2+ contaminated soil, but the further investigation into the long-term effectiveness of the MAPG binder or its applicability to other types of contaminated soil is also needed.

A green and efficient approach for the simultaneous extraction and mechanisms of essential oil and lignin from Cinnamomum camphora: Process optimization based on deep learning

The utilization and economic benefits of biomass resources can be maximized through rational design and process optimization. In this study, an innovative approach for the simultaneous extraction of essential oil and lignin from Cinnamomum camphora leaves by deep eutectic solvent (DES) and optimization of the process parameters was achieved using deep learning tools. With the water content of 40 %, liquid-solid ratio of 9.00 mL/g, and distillation time of 51.81 min, the yields of the essential oil and lignin reached 3.15 ± 0.02 % and 9.75 ± 0.15 %, respectively. Notably, the efficiency of simultaneous extraction of essential oil improved by 23 % compared to that of traditional steam distillation. Moreover, the extraction mechanism of the process was clarified. The connection between lignin with cellulose and hemicellulose was disintegrated by the DES, resulting in lignin shedding and hence accelerating the dissolution of essential oil. Moreover, the compositions of lignin and essential oil were also identified.

Comparison, optimization and antioxidant activity of ultrasound-assisted natural deep eutectic solvents extraction and traditional method: A greener route for extraction of flavonoid from Moringa oleifera Lam. leaves

To develop an environmentally sustainable and efficient extraction method for flavonoids from Moringa oleifera Lam. (M. oleifera) leaves, natural deep eutectic solvents (NADES) with ultrasound-assisted extraction was utilized in this study. After optimization of extraction parameters of NADES, including ultrasonic power, ultrasonic time, and liquid–solid ratio, the extraction yield of ultrasound-assisted NADES (UAN) composed of betaine and urea (Bet-Urea) reached 54.69 ± 0.19 mg RE/g DW, which made a 1.7-fold increase compared to traditional ultrasound-assisted traditional solvent (UATS). UPLC-Q Exactive/MS analysis revealed that M. oleifera leaves flavonoids (MOLF) was mainly composed of Quercetin 3-β-D-glucoside, Rutin, Kaempferol-3-O-glucoside, Vitexin and Quercetin. Furthermore, the COSMO-RS model was employed to verify the optimal compatibility of solubility and activity coefficient between Bet-Urea and the five primary flavonoids in MOLF. In vitro antioxidant assays verified that MOLF extracted by UAN exhibited superior antioxidant activity compared to MOLF extracted by UATS. Overall, the devised process not only augmented the extraction yield of MOLF but also effectively preserved the bioactive compounds, thus promoting the utilization of green extraction solvents in the food industry.

Extraction of ginkgolic acids from Ginkgo biloba L. exocarp and their efficacies against Tetranychuscinnabarinus

Spider mites cause substantial economic losses and are difficult to control in agricultural systems. Ginkgo biloba L. extract has potential as an acaricide, although its specific acaricidal components have yet to be identified. We used bioassay-guided isolation to isolate and purify three main ginkgolic acid (GA) compounds (C13:0, C15:1, and C17:1). Their chemical structures were identified as 1H, 13C, and IR, respectively. The LC50 values of GA C13:0, GA C15:1, and GA C17:1 against Tetranychus cinnabarinus were 777.75, 481.07, and 180.25 μg mL−1, respectively, demonstrating high toxicity. The efficacies of 23% GA soluble liquid (SL) with a dosage of 1500 a.i. g·hm−2 after 14 days were 82.45% and 85.41%, respectively, in Dali County and Chengcheng County, Weinan, China. The GA extraction process was optimized using methanol as the extraction solvent, heating and refluxing at 60 °C for 4 h at a solid-liquid ratio of 1:4, and repeating the process twice. The GA extraction rate of G. biloba exocarp was 43.2%, and the total extraction content of the three main GA compounds was 68.73%. Our optimization of the GA extraction process from G. biloba exocarp has the potential to be applied on an industrial scale, and GAs could be used as a commercial acaricide for controlling mites in the future.

A mini‐review of intensified synthesis of 1st and 2nd generation biofuels in the presence of perovskite catalysts

AbstractEnhancement of a sustainable environment through the choice of a selective catalyst with high activity, regeneration nature, and high stability is an important aspect to be focused on to achieve a high yield and maximum conversion of feedstock to biodiesel (1st generation biofuel), and also in the biomass valorization/pyrolysis (2nd generation biofuel synthesis). Depending on the nature of the catalyst and synthesis method adopted for biofuel production and biomass valorization, the variations in the process conditions, final yield, and conversion are varied accordingly. A prospective development and application of perovskite catalysts in the synthesis of 1st and 2nd generation biofuels using various process intensification strategies for the development of a clean and green environment is reviewed in this study. The synthesis of types of perovskite catalysts polycrystalline, nano‐sized, and powdered oxide are also discussed in this review. It is also concluded that, apart from other process parameters, molar ratio is one of the most influencing sensitive factors in the case of 1st generation biofuel synthesis, whereas during the production of 2nd generation biofuels, catalyst concentration and liquid–solid ratio are more significant process parameters that change based on the nature of the catalyst selected for the reaction.

Mechanics and microstructure analysis of geopolymer utilizing ilmenite tailing and metakaolin powder as alkali-activated materials

Geopolymers derived from bulk solid waste are considered ideal substitutes for cement-based materials in developing environmentally friendly construction materials. The utilization of solid waste tailings powder as a precursor for alkali activation of geopolymer can enhance the mechanical characteristics of geopolymer. This study conducted extensive experimental studies on the compressive strength, flexural strength, SEM microstructure, thermogravimetric curve, and variable influence of alkali-activated ilmenite tailings (IT) geopolymer mortar, using the liquid-solid ratio and the number of tailings as variables. An analysis was conducted on the mortar's mechanical characteristics, microstructure, and machine-learning properties. Furthermore, the impact of different atomic ratios on the structure and characteristics of geopolymer mortars was also examined. The test results revealed that the metakaolin-iron titanium tailings geopolymer, when doped with 10% ilmenite tailings, exhibited a compressive strength of 72.30MPa at 14 days. Similarly, the flexural strength of the geopolymer reached 4.76MPa at 14 days when doped with 30% ilmenite tailings. XRD analysis showed that Magnesiohornblende particles Mg-F-A-S-H and C-A-S-H gel had positive and negative correlations, respectively, with the tailings doping level. TG results indicated that the specimens exhibit enhanced thermal stability following treatment with tailings. SEM analysis revealed that combining ilmenite tailings with metakaolin formed Me-(F)-A-S-H gels. The examination of surface porosity, pore shape, and unreacted material determined that adding ilmenite tailings increased the Si/Al and Fe/Si ratios, enhancing the transformation of the lamellar structure to the three-dimensional disordered gel mesh structure. Additionally, the tailings contributed a significant amount of Ca, elevating the Ca/Na ratio (0.1−0.6) and triggering calcium precipitation within a Ca/Si range of 0.03−0.2. This increase in calcium led to a decrease in the sample's strength as the curing time was extended. Based on prior research and the application of the Gray Wolf optimization algorithm in extreme learning, a clear negative correlation was identified between the liquid-solid ratio and strength. Furthermore, increasing the Si/Al ratio enhanced the geopolymer's strength, while an extended curing time negatively correlated with strength. The impact of tailings mixing was deemed insignificant when the tailings amount did not exceed 20%. Geopolymers may derive significant environmental and industrial benefits from the improvement of their mechanical properties, thermal stability, and optimization using machine learning.

Optimizing Ultrasonic‐Assisted Extraction for Enhanced Yield of Phenolic Compounds and Antioxidant Activity in Cold Brew Coffee

ABSTRACTThis study aimed to identify the best conditions for ultrasonic‐assisted extraction (UAE) of DPPH and phenolic compounds from cold brew coffee using Box‐Behnken Design (BBD) and Response Surface Methodology (RSM). It explored the effects of solid‐liquid ratio (5%–15%), extraction time (40–50 min), and ultrasonic power (70%–80%) on these compounds, finding that all factors significantly influenced the outcomes. Statistical analysis showed the data fit a quadratic polynomial model well, with R2 values of 0.9981 for phenolic compounds and 0.9799 for DPPH radicals. Using 3D surface and contour plots from these models, the optimal extraction conditions for these compounds from cold brew coffee were determined. The highest yields of total phenolic compounds and DPPH radical were obtained when samples were extracted at a 10% solid–liquid ratio, 45 min extraction time, and 75% ultrasonic power. Under these optimal conditions, total phenolic compounds and DPPH radical were 64.10 ± 0.31 gGAE/mL and 61.90 ± 0.14%, respectively, with a maximum caffeine content of 213.13 ± 0.23 mg/L. Gamma irradiation at kGy also reduced cold brew coffee's microbial content. This research may be a new alternative for producing cold brew coffee that will save time and help extend the shelf life.

Ultrasonic-Assisted Biphasic Aqueous Extraction of Polyphenols from Vaccinium Dunalianum Leaves: Optimization, Antioxidant, and Tyrosinase Inhibition Activities.

To optimize the ultrasonic-assisted biphasic aqueous extraction conditions for polyphenolic compounds from Vaccinium dunalianum Wight leaves and investigate their antioxidant and tyrosinase inhibition activities, single-factor experiments were conducted to investigate the effects of ethanol volume fraction (%), ammonium sulfate mass fraction (%), solid-liquid ratio (g/mL), ultrasonic temperature (°C), and ultrasonic time (min) on polyphenolic content during extraction. Based on these experiments, three key factors influencing extraction were selected for response surface methodology (RSM) optimization. The results indicated that under conditions of 26 % ethanol, 20 % ammonium sulfate, a solid-liquid ratio of 1 : 30, and extraction for 35 minutes at 50 °C, the polyphenol content reached 61.62 mg/g. The relative contents of 6'-O-caffeoylarbutin, β-arbutin, and chlorogenic acid were 34.45 %, 4.56 %, and 31.06 %, respectively. The DPPH⋅ and ABTS+⋅ scavenging rates were above 95 % and 96 %, respectively, and the ferric reducing ability exhibited a significant dose-effect relationship. The inhibition rates of monophenolase and diphenolase activities of tyrosinase were 43.84 % and 35.73 %, respectively. The optimized process for ultrasonic-assisted biphasic aqueous extraction of polyphenols from Vaccinium dunalianum Wight leaves demonstrated significant antioxidant and tyrosinase inhibition activities.

Green and efficient extraction process of flavonoids from sea buckthorn fruits by natural deep eutectic solvents aided with ultrasound

In recent years, with the advantages of environment friendly, natural deep eutectic solvents (NADES) have been gradually applied for the extracting bioactive compounds from natural products. In this study, NADES-12 (betaine-lactic acid, n/n, 1:2) was selected for the first time to extract flavonoids from sea buckthorn fruit after screening of 23 NADES. The optimal technical conditions of NADES combined with ultrasonic assisted extraction (UAE) were determined by single factor test and response surface optimization test. The results showed that the optimal process for the extraction of antioxidant components by NADES-12 was 37 min extraction time, 40 °C extraction temperature, 17 % (v/v) water content, 40 mL mg−1 liquid–solid ratio, 160 W ultrasonic power, and a maximum extraction rate of 5.248 mg g−1, and the extraction yield is 2.4 and 3.1 times that of 60 % ethanol and water. The sea buckthorn extract by NADES has antioxidant activity. The study proposes a green and efficient method for the extraction of bioactive components from sea buckthorn fruit and provides a valuable basis for the exploitation of other natural plants.

Untargeted metabolomics reveals the mechanism for leaching rare earth elements from ion-adsorption rare earth ores using a composite lixiviant

Rare earth elements (REEs) are an important strategic scarce resource, and how to mine and utilise them efficiently and greenly is a difficult problem. In this study, to reduce the use of chemical reagents in the leaching process, Bacillus thuringiensis fermentation broth and magnesium acetate were used as composite lixiviants to leach REEs from ionic rare earth ores via biochemical synergy. The effectiveness of composite lixiviant for leaching REEs was studied, and the optimum leaching conditions were determined. In addition, untargeted metabolomics was used to explore metabolite differences and metabolic pathway profiles before and after leaching with the composite lixiviant. The interaction between the composite lixiviant and the rare earth minerals was also investigated by combining various characterisation tools. The results showed that the leaching rate was 96.3 % when the concentration of magnesium acetate in the composite lixiviant was 0.3 mol/L, the pH was 4, and the liquid–solid ratio was 2:1. Metabolomics analysis showed that lipids and lipid-like molecules, benzenoids, and organic acids, and derivatives contained in the fermentation broth of the complex leach play an important role in the leaching process. This study provides a new composite lixiviant for leaching ionic REEs, which can reduce the dosage of chemical reagents, provide a reference for the biochemical synergistic leaching of ionic rare earth ores, and help guide environmentally friendly and efficient leaching of ionic rare earth ores in the future.

Optimization of Extraction Conditions from Gac Fruit and Utilization of Peel-Derived Biochar for Crystal Violet Dye Removal.

Gac fruit (Momordica cochinchinensis Spreng.) is a prominent source of carotenoids, renowned for its exceptional concentration of these compounds. This study focuses on optimizing the extraction of active components from the aril of gac fruit by evaluating the effects of extraction temperature, solid-liquid ratio, and extraction time. The primary objective is to maximize the yield of gac oil while assessing its antioxidant capacity. To analyze the kinetics of the solid-liquid extraction process, both first-order and second-order kinetic models were employed, with the second-order model providing the best fit for the experimental data. In addition, the potential of gac fruit peel as a precursor for biochar production was investigated through carbonization. The resultant biochars were evaluated for their efficacy in adsorbing crystal violet (CV) dye from aqueous solutions. The adsorption efficiency of the biochars was found to be dependent on the carbonization temperature, with the highest efficiency observed for BCMC550 (91.72%), followed by BCM450 (81.35%), BCMC350 (78.35%), and BCMC250 (54.43%). The adsorption isotherm data conformed well to the Langmuir isotherm model, indicating monolayer adsorption behavior. Moreover, the adsorption kinetics were best described by the pseudo-second-order model. These findings underscore the potential of gac fruit and its byproducts for diverse industrial and environmental applications, highlighting the dual benefits of optimizing gac oil extraction and utilizing the peel for effective dye removal.

Optimization of mixed microbes pretreatment on corn straw for enhancing methane production

In order to efficiently utilize straw biomass resources, the mixed microbes were used to pretreat corn straw and anaerobic fermentation was carried out. The effects of the straw particle size, the solid-liquid ratio, and the initial pH value on both the pretreatment process and the anaerobic digestion were investigated. On the basis of single factor experiments, the pretreatment conditions were optimized using the response surface method. The pretreatment was conducted at a temperature of 30 °C for a duration of 15 days. The results indicated that the optimal parameters in pretreatment process were as follows: a straw particle size of 20 mesh, a solid-liquid ratio of 1:17, and an initial pH value of 6.5. The predicted cumulative methane production under these conditions was 3740 mL, while the experimental result obtained was (3805 ± 67) mL. With a relative deviation of 1.68% between the predicted and experimental values, the model optimized the pretreatment conditions and improved the prediction of cumulative methane production. The methane yield of corn straw achieved 243 mL/(g-VSadded).

Phase Transition and Vanadium Leaching Mechanism during Roasting of Vanadium‐Bearing Rock Coals

The phase transformation and vanadium leaching mechanism of stone coal during two blank calcined stages are systematically studied. Composition, structure, and morphology of the materials are analyzed by ICP‐AES, BPMA, XRD, FTIR, and SEM. The results show that the main components of stone coal are SiO2, C, aluminosilicate and FeS2, V2O5 is 0.70%. Two‐stage roasting is a process of deformation, melting, and reconstruction of stone coal, the oxidation of pyrite, decomposition of aluminosilicate, sulfation of calcite, combustion of carbon and the formation of calcium vanadate occur in the first stage, the oxidation of low‐price vanadium occurs in the second stage. At −0.074 mm ≥90%, liquid solid ratio 1.5:1, 10% sulfuric acid reaction at room temperature for 3 h, the vanadium leaching rate in each material is in the order of roasting slag&gt;decarbonized slag&gt;stone coal.