Pretreatment Process Research Articles

Direct Recycling of Cathode Materials from Spent Lithium-ion Batteries: Principles, Strategies, and Perspectives.

In recent years, lithium-ion batteries have become an important part of the global transition to green and low-carbon energy. However, due to the rapidly increasing demand and production of lithium-ion batteries, there is a large amount of spent batteries that need to be disposed of. The most critical and valuable recycling of spent batteries is the recycling of cathode materials. Pyrometallurgy and hydrometallurgy are traditional recycling processes aimed at extracting valuable metal elements from cathode materials. However, these methods have several disadvantages, including destruction of the structure of cathode materials, lengthy repair processes, high energy consumption and high environmental pollution. The direct recycling process is a popular repair technology for cathode materials in lithium-ion batteries. The aim is to restore or upgrade the cathode materials in a non-destructive manner or convert them into other functional products for secondary use, characterized by a short repair process, high atom utilization, lower costs and lower carbon emissions. This perspective summarizes the current status of lithium-ion battery recycling, with a focus on direct recycling of cathode materials. It describes the pretreatment process, theoretical foundations, direct regeneration strategies and perspectives and provides insights for relevant researchers.

Boosting 2G bioethanol production by overexpressing dehydrogenase genes in Klebsiella sp. SWET4adh1+adhE: ANN optimization, scale-up, and economic sustainability

Boosting 2G bioethanol production by overexpressing dehydrogenase genes in Klebsiella sp. SWET4adh1+adhE: ANN optimization, scale-up, and economic sustainability

Enhancing resource recovery from acid whey through chitosan-based pretreatment and machine learning optimization

Acid whey, a dairy byproduct with low pH and high organic content, presents disposal challenges but also potential for resource recovery. In this study, chitosan gel was synthesized and evaluated for turbidity reduction of acid whey. Machine learning (ML) models were employed to predict and optimize the pretreatment process, with the Random Forest algorithm achieving a prediction accuracy of 0.78. Using the Simulated Annealing algorithm, optimal conditions were identified, applying a 2.2% chitosan solution gel at a dosage of 24g/L to acid whey at pH 4.6 for 12h, achieving a 91% turbidity reduction, a significant improvement over the 71% obtained prior to optimization. Validation experiments confirmed its effectiveness in predicting and optimizing the pretreatment process. These findings highlight the feasibility of ML in optimizing chitosan pretreatment and demonstrate chitosan gel as a cost-effective, efficient option for acid whey, with potential to enhance resource recovery in the dairy industry.

Rapid Detection of Soil Available Phosphorus using Capacitively Coupled Contactless Conductivity Detection

Background: In China, the traditional method for analyzing soil available phospho-rus is inadequate for large-scale soil assessment and nationwide soil formulation demands. To address this, we propose a rapid and reliable method for soil-available phosphorus detection. The setup includes an on-site rapid pre-treatment device, a non-contact conductivity detection device, and a capillary electrophoresis buffer solution system composed of glacial acetic acid and hydroxypropyl-β-cyclodextrin. Methods: The on-site rapid pre-treatment process includes fresh soil moisture content detec-tion (moisture rapid detector), weighing (handheld weighing meter), stirring (handheld rapid stirrer), and filtration (soil rapid filter) to obtain the liquid sample, and direct injection (capil-lary electrophoresis detector). The phosphate ion detection parameters include capillary size, separation voltage, injection parameters, and electric injection. We used Liaoning brown soil, Henan yellow tidal soil, Heilongjiang black soil, and Anhui tidal soil as standard samples. Additionally, we used mathematical modeling methods and machine learning algorithms to analyze and process research data. Results and Conclusion: Following calibration with standard samples, the experimental blind test samples demonstrated conformity with the national standard method, exhibiting a relative standard deviation of less than 3%. The proposed pre-treatment device and non-contact con-ductivity detector are powered by lithium-ion batteries, rendering them ideal for extended field operations. The non-contact conductivity detector obviates the need for direct contact with test samples, mitigating environmental pollution. Furthermore, the neural network model exhibited the highest level of goodness of fit in chemical data analysis.

Rapid and well-controlled degradation of polylactic acid materials with bio-based GEL(pectin/α-cellulose/SiO2/CaCl2).

Polylactic acid (PLA) has been a subject of considerable interest as a degradable polymer. However, the degradation process is slow and uncontrollable. In this work, controlled degradable PLA/bio-based GEL (pectin/α-cellulose/SiO2/CaCl2) hydrophilic plasticizer composite material was successfully prepared by solution blending process. The bio-based GEL was proven to have strong water absorption properties and the ability to improve and regulate the degradation performance of PLA. The results declared that the addition of 5% GEL and 15% polyethylene glycol (PEG) to the PLA composites resulted in a degradation degree of 83% within 12h in an alkaline solution. And the rate represents a 21.2-fold increase in speed compared to pure PLA material. Under neutral and acidic conditions, the degradation degree of the modified composites was approximately 169 times faster than that of pure PLA. Meanwhile, the tensile strength of PLA composites decreased from 44.8MPa to 16.7MPa, but the elongation at break increased from 5.8% to 172% compared to pure PLA. Furthermore, the initial decomposition temperature and maximum thermal decomposition rate temperature of PLA composites were found to be reduced. The controlled degradation of PLA composites was accomplished through the regulation of GEL content. The hydrolysis degradation process under different pH laid a foundation for the pretreatment process of soil microbial degradation of PLA. The mechanism suggested that the GEL created a large number of pores on the surface and inside the material within an extremely short period of time, providing ample opportunities for soil microorganisms to invade.

Synergistic Effect of Ultrasound and Osmotic Pretreatment on the Drying Kinetics and Antioxidant Properties of Satkara (Citrus macroptera): A Novel Preservation Strategy

This study aimed to investigate the effects of combined ultrasound and osmotic pretreatment conditions on the drying kinetics and antioxidant properties, such as total phenolic content (TPC), total flavonoid content (TFC), vitamin C content, and DPPH radical scavenging activity, of dried Citrus macroptera (Satkara) fruits. The fruit slices were immersed in 10% aqueous solutions of sucrose (S), glucose (G), and fructose (F) followed by an ultrasound treatment (40 kHz) for 10, 20, or 30 min. The samples were then dried in a convective oven at 50, 60, or 70 °C and 30% relative humidity with a constant air velocity of 3 m s−1. Four thin-layer kinetic models, namely Page, Newton, Henderson and Pabis, and Logarithmic, were evaluated. Among these, Page was found to be the most suitable model for predicting the drying kinetics. The pretreatment process accelerated the drying process significantly, reducing the drying time up to 6 h. Additionally, the pretreated samples exhibited improved retention of quality attributes, with vitamin C being best preserved in S solutions, TPC in both S and F solutions, TFC in F solutions, and DPPH in all three sugar solutions (S, F, and G). The application of ultrasound during osmotic treatment also had a positive impact on TPC and TFC retention, whereas it presented a negative effect on vitamin C when used for a prolonged duration and a negligible one on the antioxidant capacity. Overall, this study provides a new perspective on the drying kinetics of Satkara fruits, and their respective properties after drying, and being subjected to combined ultrasound and osmotic pretreatment. These findings will contribute to the development of effective and efficient drying methods suitable for industrial applications to produce dried Satkara products with a minimum quality degradation.

Research on the Pretreatment Process of Rubber Powder for Modified Asphalt Applications

The application of rubber powder in modified asphalt has garnered significant attention in the field of road engineering and materials science. This paper discusses the advantages and methods of pretreating rubber powder in the process of modified asphalt application, including thermal mechanical method, chemical method, microwave radiation method, supercritical fluid induction, and biological method. By breaking the sulfur cross-linking bonds of rubber powder, increasing its surface activity, improving its dispersibility and reactivity, rubber powder modified asphalt shows significant improvements in high-temperature stability, low-temperature crack resistance, storage stability, and anti-aging performance. Future research should focus on optimizing pretreatment technology, improving desulfurization efficiency, and enhancing economic and environmental benefits to fully leverage the potential of rubber powder modified asphalt.

The Effect of Pre-Treatment on the Rehydration of Dried Apple Cube

The subject of the research was a comparative analysis of the rehydration process of dried apples in cubic form. Cubes of dried Idared apples were subjected to various pre-treatment processes, including steam blanching, microwave heating and osmotic dehydration in a sucrose solution. The pre-treatment was followed by a convection drying process conducted using two different drying systems. The rehydration process was carried out at a water temperature of 20 °C for 150 min. Rehydration kinetics, instantaneous increments in rehydrate mass and the relative and absolute moisture content of rehydrated samples were analyzed based on the tests. The rehydration process rates were also determined. It was observed that osmotic drying in a 10% sucrose solution reduced the rehydration process of dried apples by up to 32%.

Energy-Related Assessment of a Hemicellulose-First Concept—Debottlenecking of a Hydrothermal Wheat Straw Biorefinery

A hemicellulose-first approach can offer advantages for biorefineries utilizing wheat straw as it combines lignocellulose fractionation and potentially higher added value from pentose-based hemicellulose. Therefore, a tailored hydrothermal concept for the production of xylooligosaccharides and xylan was investigated. The focus was on assessing the energy requirements and potential improvements based on experimental results. The wheat straw pretreatment and the downstream processing of hemicellulose hydrolysate were modeled at a scale of 30,000 tons of wheat straw dry mass per year. The results confirmed that the hydrothermal concept can be implemented in an energy-efficient manner without the need for additional auxiliaries, due to targeted process design, heat integration and a high solids loading during hydrolysis. The resulting specific energy requirements for pretreatment and hydrolysate processing are 0.28 kWh/kg and 0.13 kWh/kg of wheat straw dry mass, respectively. Compared to thermal hydrolysate processing alone, the combination of a multi-effect evaporator and pressure-driven ultrafiltration can reduce the heating and cooling energy by 29% and 44%, respectively. However, the ultrafiltration requirements (e.g., electrical energy, membrane area and costs) depend heavily on the properties of the hydrolysate and its interactions with the membrane. This work can contribute to the commercially viable ramp-up of wheat straw multi-product biorefineries.

Synthesis and Application of LTA Zeolite for the Removal of Inorganic and Organic Hazardous Substances from Water: A Review

Industrialization and human activities have caused significant environmental challenges, with water pollution posing severe risks to human health. This underscores the urgent need for effective water treatment solutions. Zeolites, known for their high specific surface area and stability, have gained increasing attention as adsorbents for water treatment. Among zeolites, LTA varieties stand out due to their low Si/Al ratio, which enhances ion-exchange capacity, and their cost-effectiveness. This review focuses on the synthesis of low-silica LTA zeolites, particularly zeolite A, using natural materials and solid wastes without relying on organic-structure-directing agents (OSDAs). Common pretreatment processes for such synthesis are also highlighted. The review further explores the applications of LTA zeolites in water treatment, emphasizing their exceptional performance in adsorbing inorganic and organic pollutants. In particular, LTA zeolites are highly effective at removing inorganic cation pollutants through ion exchange. An updated ion-exchange selectivity order, based on previous studies, is provided to support these findings. Overall, this review aims to guide future research and development in water treatment technologies.

Automatic gripping strategy for package yarn end by composite robot based on RGB-D camera

In the pretreatment process of warping, it is extremely tedious work to take out a large number of package yarn ends from the warping frame and pull them to the warping machine; this task is currently completed manually. To automate this process, in this work, a composite robot equipped with a red-green-blue-depth (RGB-D) camera is adopted to automatically identify, locate, and grasp the package yarn ends on the warping frame. This work builds on previous research, where the yarn end was made to protrude from the package surface through the application of negative pressure. With the aim of addressing the challenge of determining depth accurately, owing to the weak features of single yarn ends, a novel approach is proposed that combines point cloud and image processing to estimate the precise spatial pose of the robot when grasping yarn ends. First, point cloud processing enables precise identification and spatial localization of the circular contour on the package end. Subsequently, image processing, with the introduction of a reinforcement operator for weak features, facilitates extraction of the yarn end and accurate determination of its relative position with the center of the circular contour on the package end. Finally, an automated grasping path for the composite robot is planned, based on geometric information about the spatial circle on the package end and the relative positioning between it and the yarn end. The accuracy of identifying and localizing yarn ends detached from the packages, as well as the effectiveness of the automatic robot gripping strategy, are validated through simulation and experimentation.

Impurity Impacts of Recycling NMC Cathodes

AbstractThe skyrocketing demands for electric vehicles cause large quantities of spent lithium‐ion batteries (LIBs) and pressure on the global supply chain, leading to raw materials shortages and cost increases. In LIBs, LiNixMnyCozO2(NMC) cathodes are one of the major cathode materials. Thus, recycling NMC cathodes from spent lithium‐ion batteries is emerging because they contain abundant valuable materials, which can be considered unique “mineral” sources. Impurities are one of the main concerns for introducing recovered materials back into new battery manufacture because impurities are typically considered to impair the properties of recovered materials. However, some impurities can beneficially act as dopants or coatings. To comprehensively understand the effects of different impurities and treat impurities properly, this review summarizes the origin and species of possible impurities which can be introduced during different pretreatment processes, analyzes the methods to remove impurities, and discusses the effects of impurities on the regeneration process and recovered materials. This work also outlines future perspectives for fundamental research about impurities and relevant challenges of the recycling industry, helps academia and manufacturers to create new impurity standards of recovered cathode materials, and suggests opportunities for achieving a circular economy for the lithium‐ion batteries industry.

Using Polyvinyl Chloride and Screen-Printed Electrodes for the Determination of Levofloxacin in the Presence of Its Main Photo-Degradants in River Water: A Comparative Study

The application of membrane sensors for the detection and quantification of pharmaceutical environmental contaminants has become a significant goal in recent years. Due to the widespread application of levofloxacin hemihydrate (LEVO) in medicine, its occurrence in the environment, especially in surface water bodies like rivers, is quite likely. Extended exposure of river water to sunlight and the photo-degradability of LEVO may facilitate its photo-degradation. To measure LEVO in the presence of its principal photo-degradants, two sensitive and selective membrane electrodes were designed. A polyvinyl chloride electrode (PVCE) and a screen-printed electrode (SPE) were constructed for the selective analysis of the investigated drug. Phosphomolybdic acid was used to prepare a lipophilic ion pair with the studied drug. All test parameters were optimized to achieve the best electrochemical performance. The electrodes demonstrated a linear range from 1 × 10−6 M to 1 × 10−2 M. The PVCE and SPE demonstrated slopes of 55.80 ± 0.70 mV/decade and 56.90 ± 0.50 mV/decade, respectively. The aforementioned sensors demonstrated satisfactory performance within a pH range of 3.0 to 5.0. The fabricated sensors were successfully utilized to accurately quantify LEVO in the presence of its primary photo-degradants. The membranes were effectively utilized to measure LEVO in river water samples without requiring pre-treatment processes.

Membrane Foulant Removal by Ozone-Biocarrier Pretreatment Technology for Industrial Wastewater Reclamation

During wastewater reclamation, organic matter is considered the dominant foulant that shortens the lifetime of ultrafiltration (UF) membranes during operation. Additionally, the mineralization efficiency of organic matter in secondary effluent is typically low due to nonbiodegradable carbon sources. Herein, a combination of ozone and a porous biocarrier reactor was applied as a novel pretreatment system to enhance organic matter removal in the effluent in a lab-scale evaluation and pilot test. The results indicated that 70% of the biopolymer was removed, and the chemical oxygen demand (COD) removal efficiency was 1.8 times higher in this combined process than in the process with a porous biocarrier alone. The UF flux increased by 16% after the combined ozonation and porous biocarrier pretreatment process compared with the process with no pretreatment. Interestingly, the genus Flavobacterium (15.59%), containing biopolymer-degrading bacteria, was observed only in the combined ozone plus porous biocarrier process. Moreover, the results show that biopolymers can be removed through the combined ozone and porous biocarrier process due to partial ozone degradation, confirming that this combined process is one of the better pretreatment procedures for organic matter removal and improves the flux of UF during the wastewater reclamation process.

Construction of energy consumption monitoring system for energy saving equipment in seawater desalination based on whale algorithm

ABSTRACT Seawater desalination has emerged as a pivotal solution to address freshwater scarcity in coastal regions, with China being a prominent adopter of this technology. This paper compares three large-scale seawater desalination projects in China: the Six Heng Water Treatment Plant, the Caofeidian Desalination Project, and the Huaihai Yu Huan Power Plant Desalination Project. Each project employs distinct desalination technologies, including reverse osmosis and dual-membrane processes. We evaluate these systems’ operational parameters, performance indicators, and cost-effectiveness over their operational lifespans. Key considerations include seawater intake, pretreatment processes, reverse osmosis desalination, energy recovery systems, and post-treatment mineralisation. The analysis highlights these desalination plants’ efficiency, sustainability, and economic viability in addressing freshwater demands in their respective regions. Insights from this comparative study contribute to optimising seawater desalination processes, enhancing water resource management, and guiding future infrastructure development efforts in coastal areas.

Enhancement of Photocatalytic Activity in BiFeO3 Nanoparticles through Electrical Polarization

This study investigates the enhancement of photocatalytic properties in BiFeO3 nanoparticles through an additional electrical polarization (poling) pretreatment process. BiFeO3, a promising multiferroic material with a narrow bandgap of ≈2. 12 eV, is well‐suited forvisible light‐driven photocatalysis. However, its photocatalytic efficiency isoften limited by insufficient photogenerated charge availability. To address this, a poling process was employed to align the ferroelectric domains within BiFeO3 nanoparticles, improving charge separation and enhancing photocatalytic activity. The findings reveal that the poling process preserves the intrinsic bandgap of BiFeO3, maintaining its visible light absorption capability. Steady‐state photoluminescence spectroscopy shows a marked increase in the intensity in poling‐treated samples, indicating enhanced charge carrier generation. Photo degradation experiments using Indigo dye as a model pollutant demonstrate that poling‐treated BiFeO3 achieves a remarkable photodegradation efficiency of 99%, compared to 56% for untreated BiFeO3. Additionally, the poling‐treated BiFeO3 retains 65% of its initial efficiency after four cycles, highlighting its durability for sustained environmental applications. This study underscores the effectiveness of poling in enhancing the photocatalytic performance of BiFeO3 nanoparticles, providing valuable insights into the development of efficient photocatalysts via domain engineering for environmental purification technologies.

The Effect of Alkaline Pretreatment of Spent Malting Grains for Biogas Production, Mathematical Modeling and Process Optimization

Spent grains from brewing industries are considered a suitable source for biogas production due to their high accessibility and affordability. However, lignocellulosic material, due to its fiber content (cellulose, hemicellulose, and lignin), meets implementation issues in the anaerobic digestion process. To enhance the efficiency of anaerobic digestion of brewery spent grain, an alkaline treatment was performed using sodium hydroxide (NaOH). The parameters of alkaline treatment were temperature (T) and soda-spent grain ratio (S/D). The characterization of the raw spent grains indicates that the organic matter (OM), total organic carbon (TOC), nitrogen (N), protein (P), N/C ratio, and pH were 99%, 57.39%, 3%, 18.75%, 19.13%, and 5.6, respectively. The respective contents of hemicellulose, cellulose, and lignin were 33.3%, 30.4%, and 6.5%. The pre-treatment process yielded a 5% reduction in hemicellulose and a 43% reduction in cellulose while increasing the volume of biogas produced from 0 to 577 mL. After pre-treatment, two biodigesters produced volumes of 23.03 mL/per day (100 °C with a soda/spent grain ratio of 0.01%) and 22 mL/per day (28 °C with a soda/spent grain ratio of 0.05%). The mathematical model showed an interaction between temperature and S/D ratio. The predictive modeling analysis presented that the maximum volume of biogas can be obtained as 23.3 mL/per day after pre-treatment of spent grains at 100 °C with a NaOH/spent grain ratio of 0.01.

Surface state study of the pre-treatment process for electroless plated aluminum alloys for EP mandrels

Surface state study of the pre-treatment process for electroless plated aluminum alloys for EP mandrels

Ecofriendly and biocompatible biochars derived from waste-branches for direct and efficient solid-phase extraction of benzodiazepines in crude urine sample prior to LC-MS/MS.

Biochars (BCs) derived from waste-branches of apple tree, grape tree, and oak were developed for direct solid-phase extraction (SPE) of five benzodiazepines (BZDs) in crude urine samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS)determination. Scanning electron microscopy, elemental analyzer, X-ray diffractometry, N2 adsorption/desorption experiments, and Fourier transform infrared spectrometry characterizations revealed the existence of their mesoporous structure and numerous oxygen-containing functional groups. The obtained BCs not only possessed high affinity towards BZDs via π-π and hydrogen bond interactions, but also afforded the great biocompatibility of excluding interfering components from undiluted urine samples when using SPE adsorbents. Variables affecting SPE of target analytes were systematically optimized including pH, ionic strength, dilution ratio, washing solution, desorption solvent, and its volume. The method of BC-based SPE combined with LC-MS/MS exhibited awide linear range of 0.03-100ng/mL, alow detection limit of 0.01-0.08ng/mL, and satisfactory recovery of 77.6-106% for the studied BZDs. Notably, this method allowed the possibility of direct loading of undiluted urine samples and avoided tedious filtration and dilution steps, which significantly simplified the pretreatment process. Additionally, these BC sorbents derived from waste-branches were ecofriendly and cost-effective, providing a sustainable alternative for the traditional SPE sorbents. Thus, the proposed method has promising application for ecofriendly, simple, efficient, and reliable monitoring of BZDs in urine samples.

Study on Refined Crushing Technology of RAP and Mechanical Properties of RAP-Doped Cement-Stabilised Macadam Base

In order to study the effect of the crushing process on the fine separation of reclaimed asphalt pavement (RAP) and the mechanical properties of cement-stabilised aggregate mixed with RAP, four crushing processes, namely small mesh hammer crushing, hammer crushing, jaw crushing, and double roller crushing, were used to separate the aggregate from asphalt in RAP materials. The effect of crushing on the grading characteristics and agglomeration condition of RAP material was investigated. RAP cement-stabilised aggregates were prepared and analysed for their mechanical properties and micro-morphology using RAP materials obtained from fine separation. The relationship between the RAP material properties and the mechanical properties of the RAP-added cement-stabilised aggregate was analysed on the basis of the tests. The results showed that crushing breaks down large-size RAP materials, leading to grade refinement, and that hammer crushing was the most effective in reducing the grade variability. The highest agglomerate dissociation rate of RAP material above 4.75 mm after small mesh hammer crushing treatment was 96.9%, and the residual mass ratios of RAP material in two grades of 0~3 mm and 3~5 mm after hammer crushing were lower than 90%. The unconfined compressive strength, splitting strength, and compressive resilience modulus of RAP cement-stabilised aggregate after crushing were greater than those of the uncrushed RAP cement-stabilised aggregate, and the crushing increased the amount of RAP in the mix to 60%. Compared with the unadulterated RAP cement-stabilised aggregate, the hydration products of the RAP cement-stabilised aggregate were reduced after crushing, and there were obvious gaps and discontinuities between the RAP material and the cement paste. The RAP gradation and agglomeration condition correlated strongly with the mechanical properties of the mixes, with RAP coarse aggregate agglomerates being the main cause of gradation variability. This paper provides theoretical support for the proposal of a pretreatment process to reduce the variability of RAP-doped cement-stabilised aggregate and improve the mechanical properties, and the research results are conducive to the recycling of high-volume RAP materials in the base.