Pretreatment Methods Research Articles

Freezing Method Assists Peracetic Ac98uid Oxidation for Promoting the Methane Production from Sludge Anaerobic Digestion

Peracetic acid (PAA) oxidation, which is a kind of chemical method for sludge pretreatment, has been verified to be valid for promoting sludge anaerobic digestion performance. However, the methane production is still limited at certain levels by this method, because excess PAA has negative effects on methanogens. This work selected a freezing method combined with PAA to form a composite sludge pretreatment technology for synergistically improving the biomethane production. According to the experimental data, the methane yield was largely enhanced from 166.4 ± 5.6 mL/g volatile suspended solids (VSS) in the control to 261.5 ± 7.3 mL/g VSS by the combined freezing (−10 °C) and PAA (0.08 g/g TSS) pretreatment, with a 57.2% increase rate. Kinetic analysis showed that the methane production potential, methane production rate, and hydrolysis rate were promoted, respectively, from 159.4 mL/g VSS, 17.18 mL/g VSS/d, and 0.104 d−1 to 254.9 mL/g VSS, 25.69 mL/g VSS/d, and 0.125 d−1 by the freezing + PAA pretreatment. Mechanism analysis revealed that the freezing + PAA pretreatment destroyed both extracellular polymeric substances (EPS) and microbial cells in the sludge, resulting in the increase in hydrolysis efficiency. Gene analysis showed that the hydrolytic microbes (Hyphomicrobium and norank_f_Caldilineaceae), acidogens (e.g., Petrimonas, Tissierella, and Mycobacerium) and methanogens (Methanosaeta, Methanosarcina, and Methanobacterium) were all enriched by the freezing + PAA pretreatment, with the total abundances calculated to be 10.65% and 22.07% in the control and pretreated reactors, respectively. Considering both technical and economic factors, the freezing + PAA method is feasible for sludge pretreatment.

Mechanism analysis of mechanical extraction of Pleioblastus amarus fibers by saturated steam pretreatment

Currently, bamboo fibers (BFs) are commonly processed through alkali boiling softening pretreatment, which generates wastewater that poses environmental pollution risks. This process is also complex and requires significant human and material resources. In contrast, the saturated steam softening pretreatment method studied in this study is environmentally friendly and significantly simplifies the post-processing of bamboo fiber preparation. Additionally, it provides methods and parameters for the hygrothermal-mechanical extraction of bamboo fibers. In this study, three-year-old bitter bamboo (Pleioblastus amarus) growing in Zhongtai town, Yuhang district, Hangzhou city, China was selected as the raw material. Firstly, bamboo fibers were prepared by crushing and mechanical extraction after softening through alkaline boiling and saturated steam pretreatment, respectively. The yield, mechanical properties, and other indicators of the fibers were then tested and compared. Subsequently, Scanning electron microscopy (SEM) was employed to observe and comparatively analyze the microstructural morphology of the two types of fibers. Infrared spectroscopy (IR) was performed on the functional groups of bamboo after alkali boiling and saturated steam softening to investigate changes in cellulose, hemicellulose, and lignin. Finally, the mechanism of mechanical extraction of bitter bamboo (Pleioblastus amarus) fibers by saturated steam pretreatment was further analyzed.

Atezolizumab neutralizing assay development: a novel way of evaluating assay cutpoint after sample pretreatment

Atezolizumab, a biotherapeutic monoclonal antibody directed against PD-L1, has been shown to be efficacious in multiple oncology indications. In clinical trials, a subset of patients developed anti-atezolizumab antibodies, necessitating the development of a neutralizing antibody (NAb) assay. A bead-based sample pretreatment method was developed to reduce high levels of therapeutic in patient serum samples. Untreated sample variability is reduced by this sample pretreatment, based on this, a novel approach was taken for determining an appropriate assay decision threshold (cutpoint). The therapeutic was added to the samples to mimic typical patient samples. The resulting assay was successfully validated and applied to sample analysis from multiple clinical trials.

Paper Waste Co-Digestion, Combined Milling, and Hydrothermal Pretreatment for Improved Biogas Production

This research, conducted in two experiments, focused on the effect of co-digestion and combined hydrothermal with milling pretreatment of paper waste (PW) and chicken manure (CM) on biogas production. In the first experiment, three reactors labeled B-D contained varying ratios of the feedstock (4:1, 3:2, 1:1) with control reactors A and E respectively containing milled paper waste (MPW) and chicken manure (CM) alone were prepared and assessed for biogas production. In the second experiment, the optimum co-digested mixture (reactor D) with a ratio of 1:1 and cumulative biogas volume (633.5mL/gVS) was selected from the first experiment and duplicated (reactor F) for the hydrothermal pretreatment. All digesters were operated at a temperature of 45oC for 32 days. The results revealed that reactor F, which contained the hydrothermally pretreated paper waste, showed a significant cumulative biogas yield of 1095.5 mL/gVS which was 1.7 times higher, surpassing control reactor D with a yield of 633.5 mL/gVS. Bacterial isolates present in the substrates and inoculum belonged to the following genera: Staphylococcus (50%), Lactobacillus (22.2%), Micrococcus (16.7%), and Bacillus (11.1%). The research outcome showed that co-digestion combined with hydrothermal pretreatment method led to enhanced biogas production. These results highlight how creative pretreatment methods can optimize waste-to-energy operations, supporting both renewable energy production and sustainable waste management.

Application of nail analysis in human biomonitoring of toxic pollutants: a review.

Nail tissue, as a keratinized biomatrix, serves as a valuable indicator of chronic human exposure to toxic pollutants. The analysis of nail samples has emerged as a prominent method for human exposure assessment, primarily due to its non-invasive sampling procedure and ease of sample storage and transportation. This review examines recent applications of nail analysis in human biomonitoring of toxic organic compounds and heavy metals, along with the various pretreatment methods that have been developed. Studies of human nail samples have revealed distinctive patterns in toxic pollutant accumulation. Brominated flame retardants exhibit significant occupational exposure differences, with concentrations reaching 2.20×106 ng/g in manufacturing workers compared to 67 ng/g in the general population. Organophosphate esters demonstrate notable regional variations, as evidenced by Triphenyl phosphate concentrations of 19.6 ng/g in China versus 770 ng/g in the United States. Additionally, the detection of organic pollutant metabolites in nails provides direct evidence of internal exposure. The 5-14 months detection window characteristic of nail samples enables retrospective exposure analysis, highlighting the promising potential of nail analysis in human biomonitoring. Recent developments include the implementation of in situ analytical methods for rapid heavy metal detection in nail samples. However, a significant challenge remains in differentiating between internal and external sources of most compounds in nails, although the identification of metabolic biomarkers for certain pollutants can minimize external interference and better reflect actual body burden. Further research is required to elucidate the relationships between nail pollutant levels, environmental exposure, and health effects. While existing studies demonstrate the considerable potential of nail analysis in human biomonitoring of toxic pollutants, additional research is necessary to validate and fully realize its practical applications.

Flowers marigold fermentation influence on the flavonoids content and polyphenoloxidase activity

Introduction. Fermentation is a biochemical process that changes the qualitative and quantitative composition of biologically active substances (BAS) and, accordingly, may change the pharmacological activity and toxicity of medicinal plants. Fermentation usually carried out for fresh medicinal plant raw materials (MPRM). However, to date, there is no information on the relationship between enzyme activity (in particular, polyphenol oxidase) and the BAS content. In this work, calendula flowers standardized for flavonoids were used as a model object. Purpose of the study. To assess the effect of calendula flower fermentation on the flavonoid content and polyphenol oxidase activity. Material and methods. The object of the study was calendula flowers (Calendulae flos, Calendula officinalis L., Asteraceae). The following fermentation options were studied: hot fermentation at 40 and 60°С; fermentation under natural conditions; cold fermentation, as well as thermal and ultrasonic pre-treatment. Immediately after the completion of fermentation, heat and ultrasound treatment, the polyphenol oxidase activity was determined in the processed fresh MPRM using the method of A.N. Boyarkin. After 6 hours of fermentation of fresh MPRM at 40 and 60°С; after 1 day of fermentation under natural conditions; after cold fermentation and ultrasound treatment, heat treatment was carried out to stop the polyphenol oxidase activity. The flavonoid content was determined spectrophotometrically by the reaction with aluminum chloride. Results. Hot fermentation of fresh calendula flowers at 40°С for 2–3 hours leads to a significant increase in the flavonoid content; hot fermentation at 60°С reduces the its content. The flavonoid content and polyphenol oxidase activity at 40°С are higher than at 60°С. A reliable relationship was revealed between the flavonoid content and polyphenol oxidase activity. Cold fermentation reduces the flavonoid content and polyphenol oxidase activity. Natural fermentation for 3 days increases the flavonoid content. Ultrasonic treatment significantly increases the flavonoid content. Heat treatment does not significantly increase the its content. Thermal inactivation of the enzyme after hot, cold and natural fermentation and ultrasonic treatment reduces the flavonoid content. Conclusion. Among all the studied methods of pre-treatment of fresh calendula flowers (hot, cold and natural fermentation, heat and ultrasonic treatment with and without thermal inactivation), the most significant increase in flavonoid content was achieved with ultrasonic treatment.

Review of pretreatment and analytical methods for environmental endocrine disruptors: Phthalates.

Phthalates, known as phthalate esters (PAEs), are among the most ubiquitous pervasive env7ironmental endocrine disruptors (EEDs), extensively utilized globally in various facets of modern life due to their irreplaceable role as plasticizers. The exponential production and utilization of plastic goods have substantially escalated plastic waste accumulation. Consequently, PAEs have infiltrated the environment, contaminating food and drinking water reservoirs, posing notable threats to human health. This review provides a comprehensive overview of research advancements in PAE detection and identifies key focal points from 2000 to 2022, utilizing the Web of Science Core Collection. Sample pretreatment and analytical methodologies for PAEs are examined based on bibliometric analysis findings. Pretreatment methods mainly include dispersive solid-phase extraction (DSPE), magnetic solid-phase extraction (MSPE), molecularly imprinted solid-phase extraction (MISPE) and solid-phase microextraction (SPME). Laboratory analytical methods such as gas chromatography (GC), liquid chromatograph (LC) and immunoassay have been described. Additionally, a discussion on the advantages and challenges of rapid on-site detection methods, in comparison to traditional approaches, is presented in alignment with the evolving demands of PAEs detection. Based on the current research progress, future studies can focus on the demand of rapid detection of PAEs.

Statistical Modeling of NaCl and FeSO4 Pretreatment Effect on Refractory Copper Ore Leaching

Black copper oxides, a significant copper resource, present challenges in leaching due to their refractory nature and complex mineralogical composition. This study investigates the sulfation dynamics of the reductive leaching process of black copper ores with the purpose of increasing the copper leaching, focusing on the influences of time and the addition of NaCl and FeSO4 on sulfation behavior. Experiments were designed to replicate industrial conditions using oxidized minerals from the Codelco Salvador hydrometallurgy plant. Multivariate nonlinear regression models and response surface methodology were employed to analyze sulfation behavior. The findings demonstrate that analytical acid consumption (AAC) exerts a consistently positive and statistically significant effect on sulfation across the sampled domain, while NaCl and FeSO₄ also influence the process. However, variations in their levels showed limited impact. Time was significant only within the 24–48 h range. The optimized model predicted maximum sulfation at 60 h with 60% AAC, 90 g NaCl, and 42 g FeSO₄, with strong alignment between the observed and predicted values. These insights emphasize the importance of pretreatment methods, including sulfuric acid curing and NaCl addition, in improving leaching efficiency.

Boosting the Reaction Rate of Blocky Aluminum-Water via Ultrasound-Based Surface Engineering in Room-Temperature Liquid Metal Solvent.

Hydrogen gas holds immense promise as a clean fuel source, yet its widespread adoption faces significant challenges in storage and transportation due to its gaseous and highly flammable nature. An increasingly attractive approach to overcoming these limitations involves reacting aluminum (Al) blocks with water to produce hydrogen, providing an alternative distribution mechanism in which Al blocks can be used as "hydrogen storage" for on-demand production at any location. However, current methods suffer poor hydrogen production rates and yields, primarily influenced by the limited contact area between Al and the catalyst, such as Ga-based room-temperature liquid metal. Herein, we introduce an energy-efficient pretreatment method to enhance hydrogen conversion efficiency by leveraging ultrasound-based surface engineering of Al blocks in a Galinstan solvent. Our strategy facilitates rapid penetration of Galinstan into the Al block microstructures via ultrasound-induced metal jets, allowing maximum contact between Al and Galinstan within a short period of time, by which the hydrogen production rates and yields of block Al are greatly improved. Overall, our results mark a significant advancement in hydrogen production methods, presenting a viable pathway toward sustainable and efficient hydrogen generation and storage.

Technological Advancement in Product Valorization of Agricultural Wastes Treated with Deep Eutectic Solvents: A Review

AbstractThe current review article investigates the potential for producing highly valuable items solely from agricultural wastes treated with deep eutectic solvents (DES). A thorough explanation of the DES s’ reaction mechanism and biomass‐treating capabilities is provided, shedding light on how green pretreatment methods can be applied to agricultural wastes in order to form high‐value products. In view of that, the influences of crucial properties of DES like viscosity, density, and recycling ability of DES are well analyzed. This review article's next goal is to compile the most recent developments for the years 2018–2023 on DES‐based valorization of agricultural wastes into a range of products, including biogas such as biohydrogen, liquid biofuels like bioethanol and butanol, and platform chemicals and reagents that are followed by novel materials. A discussion of the current criticalities and prospective avenues for further research concluded the paper. For this reason, having a thorough grasp of product value in one review paper from the potential of DES to agricultural wastes will be very helpful to the readers.

Evaluating Acid and Alkali Pretreatment Methods for Optimizing Bioethanol Production from Rice Husks

The growing demand for sustainable energy sources has highlighted bioethanol as a promising alternative to fossil fuels due to its renewable nature and lower environmental impact. This study investigates the effectiveness of acid and alkali pretreatment methods in enhancing bioethanol production from rice husks which is a readily available agricultural waste. Saccharomyces cerevisiae, a yeast isolated from palm wine, was employed for the fermentation process. Rice husks were pretreated with dilute sulfuric acid and sodium hydroxide, respectively, to facilitate hydrolysis and the subsequent conversion of cellulose to fermentable sugars. The fermentation parameters, including ethanol yield, glycerol production and inhibitor concentrations, were analysed using gas chromatography-mass spectrometry. Results indicated that alkali pretreatment consistently yielded higher ethanol production compared to acid pretreatment, with maximum ethanol concentrations of 20.13 mg/L and 17.59 mg/L, respectively. Additionally, glucose levels were higher in acid hydrolysates, while xylose and arabinose levels were elevated in alkali hydrolysates. The study also revealed significant variations in inhibitor concentrations, with acetic and formic acids present in both hydrolysates and furfural detected only in acid hydrolysates on the final day of fermentation. However, the findings support the potential of rice husks as a viable substrate for bioethanol production, thus emphasizing the importance of pretreatment methods in optimizing yield. Moreover, the co-inoculation of S. cerevisiae with pentose-metabolizing organisms is suggested to further enhance bioethanol yield and reduce by-product formation. Following this, the research contributes to the sustainable utilization of agricultural waste while advancing the understanding of lignocellulosic biomass conversion for bioethanol production.

Effects of various physical pretreatments and dextranase on the structure and physicochemical properties of porous sweet potato starch: a comparative study

Abstract Porous starch is a type of modified starch that contains a high number of tiny micropores. Due to its natural absorbent properties, porous starch has broad application prospects. Currently, enzymatic hydrolysis is predominantly used for production of porous starch, however, the hydrolysis efficiency is relatively low. In this study, sweet potato porous starch was prepared by combining physical pretreatments with dextranase, and then its adsorption properties were investigated. Ultrasonic, moist heat, and microwave pretreatment methods were used, and the structure, physicochemical properties, and adsorption capacity of resulting porous starches were detected. The microwave-combined enzymatic hydrolysis resulted in a porous starch with more compact pore structure in a shorter time. Additionally, no new chemical groups were observed in the porous starch. The treatment not only increased the solubility of starch to 5.22%, but likewise reduced the swelling power to 6.92%. Furthermore, adsorption capacity of the starch improved remarkably due to increased porosity and specific surface area. Specifically, the oil absorption improved from 51.02 to 102.79%, while the water absorption improved from 58.63 to 120.40%. This study provides an efficient method to produce porous starch from sweet potato with enhanced water and oil absorption capacity, which has promising applications in the food and pharmaceutical industries.

Improving Anaerobic Digestion Efficiency of Animal Manure Through Ball Milling Pretreatment

Anaerobic digestion (AD) can offer a promising pathway for converting animal waste into biogas. This process improves waste management practices while generating renewable energy. However, the lignocellulosic structure of animal manure, particularly in dairy and cattle manure, hinders digestion efficiency and limits biogas yield. This study investigates the application of ball milling as a pretreatment strategy to enhance the anaerobic digestion of dairy manure. By reducing particle size and disrupting lignocellulosic structures, ball milling increases the bioavailability of organic matter, thus promoting microbial conversion and boosting biogas production. Experimental results reveal that 1 h ball milling pretreatment increases biogas and biomethane production by more than 20% compared to untreated manure. Furthermore, microbial community analysis indicates that anaerobic microbes remain largely unaffected by ball milling pretreatment, unlike the changes observed with activated carbon addition. These findings suggest that ball milling is a practical, adaptable, and scalable pretreatment method to enhance the anaerobic digestion efficiency of dairy manure. It offers a sustainable solution for improved manure management and biogas production.

Utilization of municipal solid waste incineration fly ash with different pretreatments with gold tailings and coal fly ash for environmentally friendly geopolymers.

Municipal solid waste incineration fly ash (MSWIFA) is considered a hazardous solid waste, traditionally disposed by solidified landfill methods. However, solidified landfills present challenges with leaching heavy metals, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). To address this issue, this study examined two pretreatment methods for MSWIFA: sintering at 850℃ for 30 min and washing with three water baths (20 min each) at a 3:1 liquid-solid ratio. Then, the pretreated MSWIFA was employed in geopolymer synthesis, along with gold tailings (GT) and coal fly ash (CFA). The optimal raw material ratio was GT:CFA:MSWIFA = 5:4:1 after pretreatment, which resulted in maximum compressive strengths of 20.95 and 25.87 MPa for the sintered and washed samples, respectively. Washing removed 87.3 % of soluble chlorides from MSWIFA, enhancing the compressive strength of the geopolymer. High-temperature treatment effectively reduced the leaching concentrations of heavy metals and the toxic equivalent quantity (TEQ) of PCDD/Fs. The leaching concentrations of heavy metals (Cu, Zn, Cd, Pb) and the TEQ of PCDD/Fs were all below the limits established by Chinese standards GB 5085.3-2007 and HJ 1134-2020. X-ray Diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, and energy dispersive spectroscopy analyses revealed that the primary hydration products of the geopolymer are C-(A)-S-H gels. Washing treatment facilitated the formation of ettringite and Ca(OH)2, which enhanced the pore structure and optimized the performance of the geopolymer. Thermogravimetric analysis revealed the good thermal stability of the geopolymer, indicating that the high-temperature and washing pretreatments minimally impacted its thermal stability.

Effect of microwave treatment on the structural and physicochemical properties of amylose partially removed sorghum starch.

This study aimed to probe the influence of amylose in starch granules on starch modification. Part of the amylose from sorghum starch was removed through warm water leaching, and the samples were then microwaved. The effects of treatments on starch structure, physicochemical properties, and digestibility were researched. Compared to sorghum starch without partial amylose removal, warm water leaching of amylose resulted in deeper concavity of sorghum starch granules and lower crystallinity, short-range ordering, setback and breakdown values, which disrupted the structure and thus rendered the starch granules more susceptible to microwave radiation, amplifying the advantages of microwave-modified starch. In addition, the ordered arrangement of amylose and amylopectin structures within the microwave-treated sorghum starch with pre-removed amylose were more readily disrupted, allowing enzymes to pass through more readily, thus increasing the fast-digestible starch content and digestibility of the starch. In summary, partial amylose removal can be used as a pretreatment method for modifying and expanding starch utilization in food and non-food industries while providing a new idea for developing baked foods.

Pre-Treatment and Characterization of Water Hyacinth Biomass (WHB) for Enhanced Xylose Production Using Dilute Alkali Treatment Method

Lignocellulosic biomass from water hyacinth, a readily available waste material, holds potential for producing commercial products such as xylose, which can be further converted into value-added products like xylitol. However, the complex structure of lignocellulosic biomass necessitates energy-intensive processes to release fermentable sugars. Chemical pre-treatment methods, such as alkali pre-treatment, offer a viable approach to degrade lignocellulose biomass. In this study, water hyacinth biomass (WHB) was treated with 3% potassium hydroxide and subjected to autoclaving to hydrolyse the sample. The total xylose released during the process was quantified using a UV-Vis spectrophotometer and was found to 0.253 g/g of water hyacinth biomass when the sample was treated for 20 min at 2% biomass concentration. The morphological changes in the treated biomass compared to the untreated sample were analysed using Field Emission Scanning Electron Microscopy (FE-SEM). Crystallinity alterations were evaluated through X-Ray Diffraction (XRD), while Fourier-Transform Infrared Spectroscopy (FTIR) was employed to study the changes in chemical states of the biomass. The primary objective of this study was to identify a reliable pre-treatment method for processing water hyacinth biomass, facilitating the efficient release of fermentable sugars for downstream applications.

The role of aging and various surface preparation methods in the repair of nanohybrid composites

BackgroundRepairing composite resins is a less invasive alternative to complete restoration replacement. To achieve a successful bond between the existing and newly applied composite materials, various surface preparation methods, such as sandblasting and acid etching, have been explored. The aim of the study was to evaluate the effect of different surface treatments on the repair bond strength of a universal nanohybrid composite resin restorative material before and after thermal aging, by utilizing a micro-shear bond strength (µSBS) test.MethodsFor the micro-shear bond strength test, a total of 120 cylindrical (3mmX2mm) nanohybrid resin based composite specimens were prepared. The prepared specimens were divided into three groups (n = 40/per group) based on surface treatment methods: a non-aged group, 10,000 thermal cycle aging and 50,000 thermal cycle aging. The aged and non-aged specimens were further divided into four groups according to adhesive application modes and surface pretreatment methods: 1.universal adhesive/self-etch mode, 2.aluminum oxide sandblasting + universal adhesive/self-etch mode, 3.universal adhesive/etch-and-rinse mode, 4.aluminum oxide sandblasting + universal adhesive/etch-and-rinse mode. Subsequently, 0.8mmX2mm disc shape light cure resin based composite specimens were applied with a direct placement technique on the treated surfaces of all samples for repair. µSBS test was performed using a universal testing machine at a crosshead speed of 1 mm/min. Kruskal-Wallis and Mann-Whitney tests were performed for statistical analysis.ResultsThe µSBS values of the non-aged group were higher than those of the 10,000 and 50,000 thermal cycle groups, with no significant differences within the non-aged subgroup (p > 0.05). In the aged groups, significant differences were observed between adhesive application modes and surface treatments. Specifically, the etch-and-rinse mode showed higher bond strengths than the self-etch mode after 50,000 thermal cycles (p < 0.05). Sandblasting combined with universal adhesive (self-etch mode) improved bond strength, especially in the 10,000 thermal cycle group (p < 0.05).ConclusionAging reduced the bond strength of composite resin repairs, with the etch-and-rinse mode outperforming the self-etch mode in aged specimens. Sandblasting alone did not enhance bond strength. These findings highlight the importance of considering aging and adhesive strategies to optimize repair outcomes, with further research needed on long-term durability.

Transforming Agricultural Food Waste Into Bioplastics: Methods, Potential, and Technological Advances

AbstractThe improper disposal of agricultural food waste (AFW) and its associated plastic packaging significantly exacerbates environmental degradation, including pollution, greenhouse gas emissions, and loss of valuable resources, while imposing substantial economic burdens. These pressing challenges have spurred advancements in bioplastics as sustainable and eco‐friendly alternatives to conventional plastics. Here, the potential of AFW, rich in biopolymers such as starch and cellulose, as a renewable feedstock is examined for bioplastics such as polylactic acid, polybutylene succinate, and polyhydroxyalkanoates. It explores the characteristics of these bioplastics, focusing on production techniques such as extraction‐based processes, microbial fermentation, fermentation combined with polymerization, and synthesis from volatile fatty acids. Additionally, the role of AFW pretreatment methods, including physical, chemical, biological, and enzymatic approaches, in enhancing conversion efficiency is analyzed. Here, it is highlighted that recent advancements in bioplastic production have improved efficiency, biodegradability, and scalability, offering a viable substitute for traditional plastics. These findings demonstrate that valorizing AFW not only addresses plastic and food waste challenges but also promotes sustainability and circular economy principles, paving the way for greener industries and reduced ecological impact.

Recent Developments in Heavy Metals Detection: Modified Electrodes, Pretreatment Methods, Prediction Models and Algorithms

Recent Developments in Heavy Metals Detection: Modified Electrodes, Pretreatment Methods, Prediction Models and Algorithms

Coal fly ash-derived zeolite for efficient ammoniacal nitrogen removal from freshwater pearl farming wastewater.

Freshwater pearl farming in China generates wastewater high in ammoniacal nitrogen (NH₃-N) posing environmental threats. This study explores the use of coal fly ash (CFA), an industrial waste, to synthesize A-type zeolite for effective NH₃-N removal from pearl farming wastewater. The zeolite was prepared via pickling pretreatment and hydrothermal methods, resulting in a material with favorable adsorption properties, including cubic and spherical microstructures, a specific surface area of 17.5 m2/g, an average pore size of 10.7nm, and a pore volume of 0.03cm³/g. Adsorption experiments showed that NH₃-N removal followed pseudo-first-order kinetics and fit the Dubinin-Radushkevich isotherm model. Applied to actual wastewater, the zeolite achieved a 74% removal efficiency at a dosage of 70 g/L. This approach converts CFA into a valuable adsorbent, reducing its environmental impact, and enhances the sustainability of freshwater pearl farming through effective wastewater treatment, and demonstrates the potential of transforming industrial waste into functional materials for environmental remediation.