Washing Treatment Research Articles

Research on the modification technology of beta molecular sieve

The influence of temperature and time of the acid washing and hydrothermal treatment on Beta zeolite properties was examined in detail, the results revealed that acid washing at 2h and 80℃and 2h hydrothermal treatment at 650℃are the best modification operating conditions. The different SiO2/Al2O3ratio of Beta zeolite are systematically modified using optimized modification operating conditions. Beta zeolite modified from higher SiO2/Al2O3ratio of the starting Beta also has higher SiO2/Al2O3 ratio. Crystallinity of starting Beta zeolite has less effect on the modified Beta zeolite. As the SiO2/Al2O3 ratio of starting Beta increased, total acid amount of modified Beta decreased. When the SiO2/Al2O3 ratio of starting Beta is bigger, the surface area and pore volume is higher.

Impact of Soil Amendments and Improved Alkaline Water on the Physico-chemical Characteristics of the Soil, the Distribution of Salt in the Soil, the Growth, and the Yield of Hybrid Cotton Grown in Sodic Soil with Drip Irrigation

The effects of ameliorated alkali water and soil amendments on the soil properties, growth, and yield of hybrid cotton in sodic soil under drip irrigation were investigated in this field experiment at Anbil Dharma lingam Agricultural College and Research Institute, Trichy, using cotton (RCH-20) as a test crop. The main-plot treatments included drip irrigation with gypsum treatment water and drip irrigation with spent wash treatment water; the sub-plot treatments included soil application of gypsum @ 50% GR (5.2 t ha-1) and a one-time soil application of distillery spent wash at 5 lakh liters ha-1. The treatment without amendments under main plot and sub-plots was used as a control. The experiment was designed in a strip-plot design with four replications. The application of additives through irrigation water or soil dramatically lowered the post-harvest soil's pH. Plots applied with wasted wash had the greatest pH reduction (M1S1) 7.81, followed by those applied with gypsum (M2S2) 7.90 and control (M3S3) 8.15. Because there was more soluble salt present in the spent wash treated plots, there was a little rise in EC. Drip irrigation with distillery spent wash (DSW) treated water and drip irrigation with gypsum treated water, respectively, resulted in ESP decreases of (M2S2) 0.97 and (M1S1) 0.61 over control. Similarly, ESP decreased by 2.63 and 1.31 when gypsum and DSW were applied to the soil, respectively, compared to the control. The organic carbon values ranged from (M3S3) 0.47 to (M2S2) 0.92 percent. In general, an increase in organic carbon content was observed in all the treatments that received amendments (Gypsum& DSW) compared to control. Salt distribution pattern conducted in treatment of distillery spent wash @ 5.0 lakh liters ha-1 significantly increased vertical depth of soil pH ranges (7.56,7.68,7.80,8.30) and decreased EC ranges (1.05,1.02,1.00,0.95) followed by horizontal line soil pH ranges (7.54,7.51,7.49,7.50) and EC ranges (1.04,1.02,1.00,1.02) at 120 DAS after application. In the experimental field recorded vertical depth of soil increased pH and decreased electrical conductivity compared to horizontal distances of soil pH and EC. The physico- chemical properties reduced in treatment one time application of DSW @ 5 lakh liters ha-1 recorded the highest physico -chemical properties followed by the treatment receiving irrigation with gypsum bed treated alkali water and lowest was recorded in the untreated alkali water irrigated through drip system in non- amended soil.

Effect of Acetone, Ethanol, Benzene and THF Washing Treatment on the Gas Grafting Hydrophobization Efficiency of Recycled Newspaper by Palmitoyl Chloride

Effect of Acetone, Ethanol, Benzene and THF Washing Treatment on the Gas Grafting Hydrophobization Efficiency of Recycled Newspaper by Palmitoyl Chloride

Effect of hybrid sizings on the surface morphology, mechanical behavior of basalt fibers, and fiber/epoxy composite properties

AbstractIn the present study, the basalt fibers (BFs) were treated with hybrid sizings consisting silane coupling agent (3‐Glycidoxypropyl)trimethoxysilane, and silicon dioxide nanoparticles (SNPs). Using acetone washing and heat treatment, the commercial sizing previously on the BFs was removed. Next, the fibers were dip‐coated, and silanes condensed on the surface of the fibers. Fiber samples were characterized using thermogravimetric analysis (TGA), atomic force microscopy (AFM), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The test findings demonstrate that acetone extraction was an effective way to remove sizings. The AFM analysis and SEM micrographs demonstrate that SNP and silane particles were dispersed uniformly across the fiber surface. The single fiber tensile testing results indicated that the deposition of hybrid sizings enhanced the fibers strength. Because of the better adhesion between the fiber and epoxy, the hybrid sizings also improved the flexural strength by 22.28% and the interlaminar shear strength by 20.75%.Highlights Hybrid sizings (silanes and nano‐particles) on the basalt fiber surface. Characterization of the sizings and understanding of surface morphology. Hybrid sizings resulted in better tensile strength. Failure mechanisms of the fibers were observed using fractography. The effect of hybrid sizing on ILSS and flexural properties was observed.

Study on the Acidic Modification of Mesoporous HZSM-5 Zeolite and Its Catalytic Cracking Performance

Mesoporous HZSM-5 zeolites with nanocrystal stacking morphology were directly synthesized via hydrothermal methods without mesoporous templates. The synthesized mesoporous HZSM-5 was subjected to hydrothermal–citric acid washing treatment. The structural and acidic properties of the samples before and after modification were characterized using various techniques. The catalytic performance for butene conversion to propylene was investigated under atmospheric pressure, 500 °C, and a butene weight hourly space velocity (WHSV) of 10 h−1 in a continuous-flow micro-fixed bed reactor. The results show that propylene selectivity increased significantly from 24.7% before modification to 44%, and propylene yield increased from 22% to 38%. After 2 h of hydrothermal–citric acid washing modification, the catalyst maintained a butene conversion rate of 76% and a selectivity of 47% at 525 °C and a WHSV of 10 h−1 after 130 h of continuous reaction, with a propylene yield of 37%. The results indicate that moderate hydrothermal–citric acid washing modification leads to the removal of aluminum from the zeolite framework, reducing the amount and strength of acid but increasing the mesopore quantity. This helps control the reaction pathways and diffusion of intermediate products, suppresses some side reactions, and improves the selectivity and yield of the desired product, propylene, while significantly enhancing catalytic stability.

Impacts of washing and deodorization treatment on packaging-sourced post-consumer polypropylene

AbstractEmerging legal requirements will likely considerably heighten demand for high-quality recycled raw materials for e.g., packaging and automotive applications; key EU legislation mandates recycling as the future end-of-life option for municipal solid plastic waste. Yet recycled plastic use remains low due to safety concerns, undesirable aesthetic, olfactory, and mechanical properties, mainly attributable to contaminants present in recyclates. Advanced treatment options for recovered polypropylene (PP) packaging and the impact of such treatments on the polymer are currently poorly documented. We investigated the effectiveness of hot/cold washing and hot air devolatilization treatments in removing volatile substances from residential post-consumer PP plastic waste to improve its scope of application and value and to assess possible side effects on mechanical and processing parameters. Cold- and hot-washed recyclates exhibited similar contaminant levels and most substances were removed within 7 h. The recycling procedure had no adverse effects on mechanical or processing parameters although reprocessing caused polymer degradation, indicated by decreasing viscosity, elongation at break, and tensile strength. Washing and hot air devolatilization treatment of plastic wastes improve their scope of application and value by enhancing mechanical properties and considerably reducing the amounts of odorous substances, but is often not suited to high-quality applications, such as packaging. The dominance of packaging waste and strict legislation on food-grade recyclate applications will make widespread recyclate use challenging since it represents the primary use of plastic. Recyclate must consequently be extensively utilized in non-food contact applications until advances in waste sorting, washing, and devolatilization yield less contaminated recyclates with improved properties.

Effects of Post-Processing Parameters on 3D-Printed Dental Appliances: A Review.

In recent years, additive manufacturing (AM) has been recognized as a transformative force in the dental industry, with the ability to address escalating demand, expedite production timelines, and reduce labor-intensive processes. Despite the proliferation of three-dimensional printing technologies in dentistry, the absence of well-established post-processing protocols has posed formidable challenges. This comprehensive review paper underscores the critical importance of precision in post-processing techniques for ensuring the acquisition of vital properties, encompassing mechanical strength, biocompatibility, dimensional accuracy, durability, stability, and aesthetic refinement in 3D-printed dental devices. Given that digital light processing (DLP) is the predominant 3D printing technology in dentistry, the main post-processing techniques and effects discussed in this review primarily apply to DLP printing. The four sequential stages of post-processing support removal, washing, secondary polymerization, and surface treatments are systematically navigated, with each phase requiring meticulous evaluation and parameter determination to attain optimal outcomes. From the careful selection of support removal tools to the consideration of solvent choice, washing methodology, and post-curing parameters, this review provides a comprehensive guide for practitioners and researchers. Additionally, the customization of post-processing approaches to suit the distinct characteristics of different resin materials is highlighted. A comprehensive understanding of post-processing techniques is offered, setting the stage for informed decision-making and guiding future research endeavors in the realm of dental additive manufacturing.

Pemanfaatan Limbah Karbon-Aktif Melalui Reaktivitasi Termal Sebagai Adsorben Ion Kadmiun pada Lindi TPA

The leachate produced at the Kawatuna landfill, managed without proper waste treatment systems, has been found to contain heavy metals like cadmium (Cd), which contaminate groundwater and pose significant health risks. This study investigates the reduction of Cd ions in leachate through adsorption using activated carbon (AC) waste. The AC waste was reactivated via thermal methods, including phosphoric acid immersion, heating, and washing. Morphological analysis was conducted using scanning electron microscopy (SEM), and adsorption efficacy was evaluated with atomic absorption spectroscopy (AAS). The findings indicate that AC waste with a pore diameter of 2.95 µm can be effectively reused as an adsorbent through thermal reactivation. Specifically, AC treated with H3PO4 immersion and heating exhibited a pore diameter of 3.24 µm, while heating and washing resulted in a pore diameter of 2.29 µm. The Cd concentration in leachate treated with AC immersed in H3PO4 followed by heating showed a modest reduction, whereas the heating and washing treatment led to a significant decrease in Cd levels, achieving an adsorption capacity of 3.92 mg/L within 50 min. This method presents a viable alternative for managing landfill leachate at the Kawatuna site.

Heavy metal contamination (Cu, Pb, and Cd) of washed and unwashed roadside blackberries (Rubus fruticose L.).

Foraging provides a multitude of individual, social, and environmental benefits. With green spaces decreasing in the United Kingdom, there is an opportunity for roadside verges to become valuable foraging resources; however, there is public concern over the safety of roadside forage. Human ingestion of heavy metal contaminants, such as copper (Cu), lead (Pb), and cadmium (Cd), originating from traffic activity, induces toxic effects in the body. Therefore, maximum Cu, Pb, and Cd guideline limits for human consumption in small fruits were established. However, studies of heavy metal concentrations in roadside forage and the effects of surface washing on concentrations are limited. This study examined Cu, Pb, and Cd in washed and unwashed wild blackberries (Rubus fruticose L.) along a main road in Kent, UK, and compares the values with maximum guideline limits. In all 44 samples, Cu, Pb and Cd concentrations were well below the maximum guideline limit or daily reference intake (RI) value. Cu and Pb concentrations were below the maximum daily intake in every sample if foragers eat one portion (80 g) of berries a day, but consuming a larger quantity of berries per day (e.g., 1 kg) could lead to an intake above the guideline limit for Cu (1 mg) and Pb (0.1 mg), but not Cd (0.03 mg). Washing did not significantly reduce the concentrations of Cu (p = 0.174) or Cd (p = 0.752) in blackberries, but did significantly reduce the Pb concentration (p < 0.001). However, Pb concentration was below maximum guideline limits for every sample regardless of washing treatment. Thus, wild blackberries collected from the roadside were suitable for human consumption, although the findings are not representative of all foraged berries or road networks. Integr Environ Assess Manag 2024;20:2107-2115. © 2024 The Author(s). Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Multifunctional, efficient, and durable composites of conductive PMIA/Ag membrane

Developing high-efficiency electromagnetic interference (EMI) shielding composite membranes along with additional functionalities to extend the application scenarios is highly desirable for the next generation electronic devices. Here, we report an ultrathin and flexible EMI shielding materials with sensitive Joule heating and outstanding infrared stealth performance was fabricated from poly-m-phenylene isophthalamide (PMIA) and Ag nanoparticles (AgNPs) through an innovation and simplicity method of electrospinning and electroless plating. Profiting from a continuous three-dimensional (3D) conductive network, the final membrane achieves an outstanding EMI shielding effectiveness (SE) of 100.51 dB (in X-band), a remarkable Joule heating properties with a fast thermal response and low driving voltage (<0.5 V), and an outstanding infrared stealth with a low infrared emissivity (0.28). Meanwhile, the prepared composite membrane demonstrates stable EMI SE even after water washing, continuous bending, and heating treatment. This work integrates high-performance fiber PMIA, characterized by high heat resistance, flame retardancy, self-extinguishing properties, and chemical resistance, with functions such as EMI shielding, infrared stealth, and autonomous thermal management. It has great development potential if utilized in specialized combat uniforms under harsh conditions.

Improving the photoelectrochemical performance of WO3 photoelectrodes by controlling the pH and Na+ ion concentration through varying the number of H2WO4 precipitate washing treatments

In this study, WO3 thin-film photoelectrodes were grown on fluorine-doped tin oxide (FTO) substrates using the spin coating method. The H2WO4 precipitate underwent various washing treatments to prepare the Na2WO4 precursor solution, which was subsequently used for growing photoelectrodes. We found that washing with the H2WO4 precipitate changed the Na + ion concentration and pH of the precursor solution containing the H2WO4 precipitate and subsequently affected the thickness, X-ray diffraction (XRD) peak intensity, optical energy bandgap, flat-band potential, and photoelectrochemical (PEC) properties of the WO3 photoelectrode. In particular, the Na + ions in the H2WO4 precipitate solution negatively affected the PEC properties by causing photogenerated electron–hole recombination and worsening the adhesion between the substrate and the WO3 thin film. Therefore, H2WO4 precipitate washing treatment is crucial for reducing the Na + ion concentration in solutions containing H2WO4 precipitate. Consequently, among the samples grown using different numbers of washing treatments, the sample grown using 12 precipitate washing treatment cycles exhibited the highest photocurrent density of 1.37 mA/cm2 and a photostability of 97.5 %. In this study, the morphological, structural, optical, electrical, and PEC properties of WO3 photoelectrodes subjected to H2WO4 precipitate washing treatment were systematically analyzed.

The Acid Roles of PtSn@Al2O3 in the Synthesis and Performance of Propane Dehydrogenation.

In this study, a PtSn/Al2O3 catalyst with bimetallic uniform distribution in the sphere was synthesized. The PDH performance and characterization analyses, such as with FTIR, XPS, and NH3-TPD, were investigated. The effects of acid on the PDH performance were analyzed. Citric acid (CA) acted as a competing adsorbent in the preparation process of the PtSn/Al2O3 catalyst to synthesize the uniform catalyst. Water washing and alkali-treated samples were also studied. SEM line scanning revealed that increased the apparent concentration of Pt metal from 0.23 to 0.30 with citric acid. In contrast to the fresh PtSn/Al2O3 catalyst, the addition of citric acid increased the PDH selectivity from 74% to 93%. After alkali or water washing treatments, the catalyst's selectivity further increased to 96%. Strong acid sites promoted the breaking of C-C bonds during the PDH reaction, resulting in more methane and ethylene byproducts, and decreased catalyst selectivity for fresh PtSn/Al2O3. From the PDH reaction thermodynamic analysis, a relatively sub-atmospheric pressure environment with a lower propane pressure could be the reasonable choice.

Remediation of soils contaminated with methomyl using electrochemically produced gaseous oxidants

This prospective work focuses on the use of two different gaseous oxidants (chlorine dioxide and ozone) to remediate soil polluted with methomyl in two different applications: ex-situ and in-situ. In the first, the soil washing is integrated with the bubbling of the oxidant, while in the second, the gas was introduced by a perforated pipe located sub-superficially. Regarding the soil washing treatment, results demonstrate that direct use of ozone is not very efficient, although an important improvement is obtained following activation with hydrogen peroxide or UV light. In contrast, chlorine dioxide exhibited complete methomyl depletion from the soil, although with higher energy consumption and technical complexity compared to ozone. The direct dosing of the gaseous oxidants in perforated pipes is effective, achieving methomyl removals of 7.8 % and 9.2 % using ozone and chlorine dioxide, respectively. In these cases, soil conditions are not significantly modified, which becomes an important advantage of the technology as compared with other electrochemically assisted soil remediation process, in which large regions of the treated soil are affected by important changes in the pH or by depletion of ions. This lower impact makes these novel technologies more promising for further evaluations.

ZIF-Co3O4@ZIF-Derived Urchin-Like Hierarchically Porous Carbon as Efficient Bifunctional Oxygen Electrocatalysts.

Co3O4 nanoparticles were sandwiched into interlayers between ZIF-8 and ZIF-67 to form ZIF-Co3O4@ZIF precursors. Pyrolysis of ZIF-Co3O4@ZIF yielded an urchin-like hierarchically porous carbon (Co@CNT/NC), the thorns of which were carbon nanotubes embedded Co nanoparticles. With large specific surface area and hierarchically porous structure, as-prepared Co@CNT/NC exhibited excellent bifunctional oxygen electrocatalytic performances. It has good ORR performance with E1/2 of 0.85 V, which exceeds the Pt/C half-wave potential (E1/2=0.83 V). In addition, Co@CNT/NC has an OER performance close to that of RuO2. To further demonstrate the effect of Co modifying on the properties, the samples were subjected to acid washing treatment. Co-based nanoparticles were proved to After acid washing, there was obvious loss of Co particles in Co@CNT/NC, resulting in poor oxygen electrocatalysis. So, the pyrolysis products of ZIF-8-Co3O4@ZIF-67 retained large specific surface area and porous structure can be retained, and on the other hand, the carbon tube structure and original polyhedron framework. Besides, existence of Co nanoparticle@carbon nanotube provided more active sites and improved the ORR and OER performances.

Evaluating the effectiveness of different household washing techniques for removal of insecticides from spinach and chickpea leaves by micellar liquid chromatography

In the past few decades, the employment of green analytical approaches in chromatographic method development has attracted the analytical separation community. The greenness of the developed method depends upon the toxicity of solvents and the amount of generated post-analysis waste generated. In this concern, micellar liquid chromatography (MLC) is a simple and rapid technique that generates very low toxic waste compared to traditional chromatographic pesticide detection methods. Here, MLC method has been validated and applied for the determination of monocrotofos (MCF), imidacloprid (ICP), dimethoate (DM) and profenofos (PFF) in spinach and chickpea leaves. The optimized mobile phase was 0.065 M SDS-2 % 1-propanol, 0.01 M NaH2PO4 buffered to pH 7. A C18 column was used for separation with a flow rate of 1 mL/min. The developed method has been validated following the guidelines of SANTE/11,312/2021 and ICH guidelines for; limit of quantification (0.05–0.20 mg/kg), linearity (r2> 0.997–0.999), precision (<6.3 %), accuracy (96.3 %–99.8 %) and robustness (<6) in real samples. ICP and MCF, apart from DM and PFF, were detected in the present work. After detecting insecticides in spinach and chickpea leaves both were washed with different household chemicals i.e. normal, lukewarm, common salt, lemon juice water and commercial ozonizer. Based on five washing techniques with insecticide concentration time intervals reduction rates were calculated for each washing treatment. The results show that lemon juice, common salt water, and ozonizer can be used as washing techniques for the reduction of superficial and systematic residues of ICP and MCF. Common salt and lemon juice water were better for washing over vinegar and potassium permanganate (KMnO4) as they enhance the colour of the green leafy vegetables and are available in every Indian kitchen. They can be easily used by lower socioeconomic classes who cannot afford KMnO4 and vinegar.

Study on the decay behavior of a flexible sensor based on silver fiber fabrics

Abstract Flexible sensors are affected by various external factors during their use, such as water, thermal oxidation, and ultraviolet light, which causes a decrease in their sensitivity, but little research has been done in this area. This paper investigates the effects of washing, acid, ultraviolet, and thermal oxidation treatments on flexible sensors made of silver fiber fabrics, and the sensitivity and sensing performance before and after the treatments are compared. The findings show that the flexible sensor in use has a broad response range (0–70%) and strong stability (&gt;1000 cycles). The sensitivity decreased significantly after washing, acid treatment, UV treatment, and thermal oxidation treatment but maintained good stability after 1000 tensile cycle tests.

Changes in bacterial community characteristics on surface of fresh-cut yams during cold storage after ethanol combined ascorbic acid washing

In this study, the quality changes of fresh-cut yam slices treated with a mixture of ethanol (25%, w/w) and ascorbic acid (1%, w/w) treatments (EA) were assessed, and the bacterial community composition and their metabolic functions for these samples were investigated. Results showed that EA washing treatment notably reduced the respiratory intensity and microbial growth of fresh-cut yams in packaging during refrigeration, maintained the tuber firmness, and delayed discoloration. Proteobacteria was the main phyla significantly associated with off-flavor of yams, Bacteroidetes was the sensitive genera and was positively correlated to CO2 content of the packaging bag and sensory evaluation of yams. Interestingly EA could specifically remove the pathogenic bacteria of Pseudomonas (Proteobacteria), greatly destroy the stability of the bacterial community network on the fresh-cut yam slices’ surface, and achieve a better antibacterial effect. EA washing treatment reduced the metabolic capacity of bacterial community and was helpful to delay the aging and spoilage of fresh-cut yams, meanwhile, significantly inhibited transferase expression, and could help to maintain the quality of the fresh-cut yams. In conclusion, ethanol and ascorbic acid mixture washing agent altered the successional process of bacterial communities to reduce the pathogenic bacteria of fresh-cut yams during cold storage.

Robust construction of polyvinyl alcohol intercalated graphene oxide nanofiltration membrane for desalination via pervaporation

The construction and modification of a Graphene Oxide (GO) membrane, incorporating polyvinyl alcohol (PVA) cross-linked with maleic acid (MA) and supported by a nylon membrane, have been successfully completed. Systematic variations in PVA and MA concentrations were conducted to achieve membranes with favorable characteristics, stability, and excellent desalination performance. Optimization studies utilizing the Central Composite Design (CCD) revealed that the most optimal desalination results were obtained with 10 mL of PVA (0.1 mg mL−1) and 0.9 M of MA (GO-MA0.9-PVA10/Nylon membrane). Experimental findings demonstrated that the inclusion of PVA and MA resulted in an increased interlayer distance of GO and enhanced membrane stability. The addition of PVA increases GO membrane hydrophilicity, while the addition of MA reduces membrane hydrophilicity. The GO-MA0.9-PVA10/Nylon membrane exhibited the highest desalination performance, boasting a rejection value exceeding >99.9% and a permeance of 18.76 kg m−2.h−1 under 1% NaCl feed at a temperature of 50 °C. This membrane demonstrated consistent desalination performance stability over an extended period of up to 70 h. Moreover, it exhibited durability through 8 cycles of 24-h usage with washing treatment. In conclusion, the GO-MA0.9-PVA10/Nylon membrane is strongly recommended for practical applications, outperforming other membrane options based on the comprehensive evaluation of its stability and desalination efficiency.

Preparation and characterization of cementitious materials from dedioxinized and dechlorinated municipal solid waste incineration fly ash and blast furnace slag

To address the resource utilization issue of MSWI fly ash, a method has been proposed to prepare cementitious materials using harmlessly processed MSWI fly ash (HPFA). After washing and thermal treatment, The physicochemical properties of HPFA were characterized using QXRD, ICP, XRF, and GC-MS. Cementitious materials were prepared using HPFA, gypsum and blast furnace slag (BFS) as raw materials, Through XRD, TG, FTIR, TEM, and SEM-EDS methods, the hydration and hardening characteristics were investigated, and the leaching of heavy metals from solidified materials in simulated surface water and landfill environments was evaluated using ICP-MS. The results indicate that the harmless treatment can effectively reduce the chloride content and dioxins in MSWI FA but still contains heavy metals. The addition of HPFA (10%-50%) can enhance the compressive strength of cementitious materials, accelerate the exothermic process of cement hydration, and increase the total heat release of hydration, implying an improvement in the degree of hydration of the system.HPFA could effectively promote the hydration of gypsum and BFS, resulting in the higher formation of ettringite and C-(A)-S-H（C/S=1，Al/Si=0.3）.The formation of C(Mg/Fe)-(A)-S-H suggests that the Fe-Mg solid solution phase in HPFA may have participated in the hydration reaction. The increased stability of highly cross-linked (Q4) silicate tetrahedral structure with time implies that the material may have good durability. The leaching amount of heavy metals met the standards of Class I surface water in GB3838–2002 and GB5085.3–2007 which implies that the material has environmental safety. This study innovatively provides a preparation path for harmless MSWI fly ash and cementitious material ratios, reveals the hydration mechanism of HPFA in cementitious materials, evaluates the solidification ability of heavy metals, and provides important ideas for the resource utilization of MSWI fly ash.

Modeling rapidly discriminative strategies of Cr contaminated soils through machine learning

Soil washing is employed to prevent the issue of Cr re-oxidation following the remediation of Cr-contaminated soil by transferring contaminants from the soil to the wash solution through the dissolving action. Nevertheless, rapidly screening effective washing agents remains challenging. This study conducted batch experiments to gather dataset on key factors (soil properties, Cr sequential extraction and type of washing agent) and Cr content after washing with 250 experimental data points. We developed 12 machine learning models, among which the light gradient boosting machine model excelled in predicting Cr content after washing, determining soil suitability for washing. Furthermore, the adaptive boosting and random forest models preferably predicted Cr content after various washing agents treatments, facilitating optimal detergent identification. Based on the feature analysis, soil pH, exchangeable potassium, reactive iron oxides, and Cr sequential extraction can account for most of the differences in washing treatment. To further validate our model, we used an additional 60 experimental data points, including soil properties with pH values beyond the range of the initial 250 data points. The R2 value of the predicted fit to the actual results was 0.801. This study provides the feasibility of improving the efficiency of technical remediation of Cr-contaminated soils.