Chemical Neutralization Research Articles

Characterization of Continuous Neutralization of a Chemical Warfare Agent and Its Simulants.

The persistent threat posed by chemical warfare agents (CWAs) necessitates the development of efficient and safe methods for their neutralization. In this study, we investigated the continuous neutralization of CWAs and their simulants using flow chemistry, which combines the benefits of safety, precise control over reaction parameters, and scalability. We focused on the integration of continuous-flow reactors to achieve controlled and rapid neutralization, thus addressing challenges such as the need for rapid reaction kinetics and the establishment of robust pathways for neutralization. Because the flow-chemistry approach can contribute significantly to the development of neutralization technologies for CWAs, we performed a thorough characterization in terms of reaction kinetics and neutralized product identification. The results demonstrated that the proposed continuous-flow-type neutralization reaction was faster and more efficient than batch-type neutralization reactions. Furthermore, in the early stages of the neutralization reaction, flow-type neutralization not only required less neutralizing agent than batch-type neutralization but was also faster. Thus, the chemical neutralization process proposed in this study can be used as a pragmatic foundation for developing demilitarization methods for CWAs.

An Overview on Bioeconomy in Agricultural Sector, Biomass Production, Recycling Methods, and Circular Economy Considerations

This review examines the essential components of a circular economy (CE) in relation to the agricultural sector. The bioeconomy and circular economy are crucial for sustainable global industrial growth, focusing on closed-loop systems. The sustainability debate centers on intergenerational equity and natural capital. The CE requires new environmental technologies and global coordination in order to combat climate change and biodiversity loss. In addition, efficient food production and waste reduction are essential due to population growth. However, biomass is vital for a bio-based economy, impacting food waste and climate change. Grasslands support sustainable dairy production and carbon sequestration. Thus, effective waste and wastewater management are critical, with biomass energy providing renewable alternatives. Nonetheless, biofuels remain key for sustainability, focusing on pollution control and Green Chemistry. It is well known that sustainable transportation relies on bioenergy, with ongoing research improving processes and discovering new fuels. One notable challenge is managing heavy metals in biofuel production, and this underscores the need for eco-friendly energy solutions. The main purpose for this review paper is to create a connection between circular economy aspects and the agricultural system, with focus on the following: bioeconomy research, biomass utilities, and biofuel production. Extensive research was performed on the specialized literature by putting in common the main problems. Key subjects in this paper include the use of biomass in agriculture, the problems of plastic recycling, and the function of the CE in mitigating climate change and biodiversity loss. Efficient food production and waste minimization are highlighted due to their relevance in a growing population. The study’s detailed research and discussion aim to give important insights into how these practices might promote economic development and sustainability. Furthermore, the study covers important waste management issues such as food waste, plant composting, and chemical waste neutralization. These topics are critical to understanding the circular economy’s broader implications for minimizing environmental damage and implementing sustainable waste management strategies.

Impact of substrate thickness and surface roughness on Al/Ni multilayer reaction kinetics

Reactive multilayers comprising alternating nanoscale layers of Al and Ni, exhibit potential across various applications, including localized heating for welding and joining. Control over reaction properties is pivotal for emerging applications, such as chemical time delays or neutralization of biological or chemical weapons. This research offers insights into the intricate interplay between substrate thickness, surface roughness, and the behavior of Al/Ni reactive multilayers, opening avenues for tailored applications in various domains. To observe this interplay, silica with various thicknesses from 0.4 µm to 1.6 µm was deposited on polished single crystalline Si and rough poly‐Si base substrates. Additionally, to analyze the impact of varying silica thickness along the sample length on reaction behavior, silica in step‐like shape was fabricated. Subsequently, Al/Ni multilayers with 5 µm total thickness and 20 or 50 nm bilayer periodicities were deposited. Reaction velocity and temperature were monitored with a high‐speed camera and pyrometer. Results indicate that silica thickness significantly affects self‐propagation in multilayers. The reaction is not self‐sustained for silica layers ≤ 0.4 µm, depending on bilayer periodicity and substrate roughness. The velocity increases or decreases based on the direction of reaction propagation, whether it moves upwards or downwards, in relation to the thickness of silica.This article is protected by copyright. All rights reserved.

Theoretical research on efficient electrocatalysis of CO2 reduction reaction by borophene loaded transition metals

Electrocatalytic conversion of CO2 into chemical or fuel is regarded as a viable approach to attain energy conversion, chemical energy storage and carbon neutrality. Borophene exhibits great potential as an electrocatalyst owing to its exceptional physical and chemical attributes. β12-borophene incorporated transition metal (TM) as single atom catalysts (SACs) have been devised for the electrocatalysis of the carbon dioxide reduction reaction (CO2RR). Through the exploration of the most favorable CO2RR pathway and the comparison of Gibbs free energy (ΔG) during the potential determination step (PDS), the catalyst exhibiting remarkable catalytic activity for CO2RR are chosen. Wherein, the overpotential of Nb-β12 and Ru-β12 produce CO is only 0.02 and 0.03 V. The overpotential of Ru-β12 and Rh-β12 in generation of HCOOH product is only 0.03 and 0.06 V. Additionally, the catalytic performance of Rh-β12 in CO2 reduction to CH3OH and CH4 showcases exceptional performance, with overpotential of 0.65 and 0.79 V. Unexpectedly, the overpotential of Cd-β12 and Mo-β12 are 0.01 and 0.09 V for hydrogen evolution reaction (HER). The research offers invaluable insight for systematic designs and screening of catalysts for the electrochemical CO2RR.

Alkaline Chemical Neutralization to Treat Acid Mine Drainage with High Concentrations of Iron and Manganese

Due to its high acidity and toxic metal content, acid mine drainage (AMD) needs to be properly treated before being discharged into the environment. This study took the AMD collected from one specific mine in China as a sample and investigated the treatment methodology for AMD. The water quality of the AMD was measured, and the sample was treated with caustic soda (NaOH) and shell powder (one kind of conventional neutralizer, mainly composed of CaCO3) by the neutralization method. The results show that the AMD has a relatively low pH (2.16) and contains high concentrations of Fe (77.54 g/L), Mn (621.29 mg/L), Cu (6.54 mg/L), Ca (12.39 mg/L), and Mg (55.04 mg/L). NaOH was an effective neutralizer to treat the AMD and performed much better than shell powder. Various metals were precipitated, in the order of Fe(III), Cu, Fe(II), Mn, Ca, and Mg. The metal removal mechanisms included precipitation, adsorption, and co-precipitation. The optimal reaction conditions were the reaction duration was selected as 5 min and the mass ratio of NaOH to AMD was 0.16:1 (w:v). By this stage, the pH rapidly increased from 2.16 to 8.53 during AMD-NaOH interactions and various metals were efficiently removed (from 86.71% to 99.99%) by NaOH. The residual mass concentrations of Fe, Mn, Cu, Ca, and Mg after the treatment were 1.52, 1.77, 0.10, 1.65, and 2.17 mg/L, respectively. These data revealed that NaOH was a good treatment regent for this kind of AMD, based on the discharge criteria of China (GB28661 2012). Also, the shell powder was a helpful neutralizer for pH adjustment and copper removal. This neutralization method has the advantages of convenient operation, high speed, good effect, simple equipment, and low infrastructure cost. In addition, the resulting neutralized residue is a valuable and high-quality raw material, which can be used in metal smelting and separation.

Evaluation of antibacterial activity and influencing factors of normal and nanostructured copper-based materials

BackgroundCopper-based materials have garnered extensive recognition for their effective nature against microorganisms and their minimal toxicity. However, the evaluation for their antibacterial activity is still in its nascent stages, and the evaluation results based on existing criteria are not representative of real-world application. AimTo evaluate the antibacterial activity and primary determinants of influence of copper-based materials in order to investigate their practical antibacterial activity and potential mechanisms of such materials. MethodsStaphylococcus aureus and Escherichia coli bacterial suspensions were applied via inoculation onto the surfaces of normal and nanostructured copper foil. Following incubation of the inoculated surfaces under diverse experimental conditions—including varying compositions of the bacterial suspension, the use of chemical neutralizers, the existence of organic interferents, and low temperature and humidity—surviving bacteria were enumerated. Using the scanning electron microscopy and X-ray photoelectron spectroscopy, the surface changes of copper-based materials were examined. FindingsFollowing 1 h of exposure to 37 °C and 90% relative humidity, Staphylococcus aureus was reduced by 4.45 log10 on normal copper foil, while all of the bacteria were eradicated on nanostructured copper foil. In addition, it was discovered that preparing a bacterial suspension with PBS results in a significant number of Escherichia coli fatalities during the test, whereas using TPS promotes the bacteria's normal growth. Furthermore, the outcomes of the antibacterial activity test were diminished when chemical neutralization was employed, and the presence of organic interferents had distinct impacts on normal copper foil and nanostructured copper foil. Additionally, low temperatures and humidity diminished the antibacterial activity of copper foil, whereas normal copper foil produced significantly better results. ConclusionWhile copper-based materials exhibit robust antibacterial activity as determined by standard assays, their efficacy in real-world applications is subject to various influencing mechanisms. In order to objectively evaluate the antibacterial activity of copper-based materials and provide precise guidance for their development and practical application, it is essential to regulate test conditions with targeted.

Chemical Modification of Iron – Rich Beta Intermetallic Phase in Aluminium-Silicon Alloys: A Short Review

Iron-rich intermetallic phases normally form during solidification of aluminium – silicon alloys with low level of iron. This type of phases is known for creating a mechanical properties degradation, especially the beta intermetallic phase (β-Al9Fe2Si2). Various studies and researches have led to mitigate the harmful effect of these phases through physical separation, thermal treatment or microstructure alteration by chemical neutralization such as with Mn addition which changes their structure into cubic alpha phase (α-Al15(Fe,Mn)3Si2). In this paper, the effect of chemical addition was reviewed and discussed in terms of effectiveness of modifying the crystal structure or morphology of beta intermetallic phase

Electroneutralization with simultaneous highly-efficient desalination exemplified by acidic brackish wastewater

Chemical neutralization has commonly been employed for the treatment of acidic brackish wastewater through the addition of external alkaline chemicals. However, this approach can potentially compromise the health of aquatic environment and resource sustainability. In this study, an innovative electroneutralization stack incorporating highly-efficient desalination was developed as a green solution for acidic hot-spring discharge treatment. Two distinct stack configurations, i.e., AECE and AEBP, were designed to evaluate the performance of simultaneous neutralization and desalination under different operating conditions. The results demonstrated the effectiveness of neutralizing acidic discharges while concurrently achieving a significant reduction in salinity. The brine solution produced during the process also presented the possibility of being harnessed as a valuable resource. Notably, the design parameters for the process were determined using a first-order kinetic model integrated with the Nernst-Planck equation. The maximum rate constants for sulfate and chloride removal were found to be 0.129 min−1 and 0.125 min−1 for AECE, and 0.039 min−1 and 0.042 min−1 for AEBP, respectively. The corresponding chloride-to-sulfate selectivities were observed to range from 0.42 to 1.00 for AECE, and from 0.15 to 1.21 for AEBP. Furthermore, the optimal operational conditions were identified through a comprehensive multi-objective assessment, resulting in process energy consumption ranging from 1.5 to 2.2 kWh/m3, while maintaining a clean water productivity of ∼30 L/m2/h. Significantly, in comparison to conventional chemical neutralization methods, the developed electroneutralization process demonstrated a substantial reduction in operating costs by 2 to 5-fold, along with a remarkable decrease in CO2 emissions (by approximately 4-fold) and the avoidance of sludge generation.

Process and mechanism of recovering layered double hydroxides (LDHs) from acid mine drainage (AMD) and synergetic removal of manganese

The neutralization-precipitation method is widely used for treating acid mine drainage (AMD). However, the accumulation of sludge and the requirement for a high pH for the precipitation of Mn2+ limit the widespread application of this technology. In this work, layer double hydroxides (LDHs) were obtained by chemical neutralization of AMD, and the mechanism of LDHs for synergistic removal of Mn2+ was investigated by studying the morphological of metal elements during the neutralization process. The results showed that pH=8.5 was the critical condition for the formation of LDHs, and the sludge mainly consisted of Mg-Al-LDHs and manganese oxides. With increasing pH, Mn2+ was synergistically removed by LDHs through ion exchange (at the site 6) and complexation (with Mg-O). At pH=9.0, the concentration of Mn2+ was reduced to 1.5 mg/L, but it should be noted that high pH could destroy the structure of LDHs. Moreover, LDHs recovered from actual AMD were also found to have the ability to remove environmental pollutants. These findings not only enhance our understanding of the morphological change of metal elements during the neutralization process and the mechanism of Mn2+ removal, but also provide new insights for the recycling and utilization of neutralized sludge.

A systematic investigation on the influence of the chemical treatment of natural fibres using the Fuzzy TOPSIS Method

Chemical treatment (hazardous waste) is the conversion of hazardous waste into non-toxic gases, to change or change the chemical characteristics of waste Treatment methods are used, for example in water By decreasing solubility. OracidityNeutralization or pH adjustment (neutralization or precipitation), oxidation and reduction, hydrolysis and Photosynthesis, chemical oxidation (ozonation, (electrolytic oxidation, hydrogen peroxide) and chemical removal (alkali metaldichlorine, alkali)chemical treatment processes Various (commonly used) including metallization/ soCommonly Activated Chemical Treatment Processes: Chemical Precipitation, neutralization absorption, disinfection (chlorine, ozone, UV light) and ion exchange. from plant kingdomCommon natural fibres obtained are Cotton, Flax, Jute, Bamboo, Sisal and Jute, Natural fibres. The main component Natural fibres. The main component Popular as angora and mohair We get fibres, plant fibres include seed hairs such as cotten; Flax andstem (or bast) fibres like jute, leaf fibres like sisal; and coconut-like husks fibres. Animal fibres also include secretions such as wool, hair, and silk. Research significance: In this paper, various chemical properties of in natural fibre-reinforced composites Use natural fibres Changes have been reviewed. Alkali, Silane, Acetylation, Benzoylation, Acrylation, malate coupling agents, isocyanates, Permanganate and other chemical treatments are discussed. to the fibre surface Chemical treatment of fibre between polymer matrixAimed at improving adhesion. Water absorption of composites decreases and their mechanical Properties are improved. Method: Fuzzy TOPSIS (Order by Similarities for Ideal Solution technique for prioritization) similar options. Further It also automates the process and selection Ambiguity, uncertainty in the process Can also be used to relieve Technology in general Used to solve decision problems. This is for all alternatives in the technique problem Based on inter-comparison. Alternative: Cotton, Jute, Flax, Hemp, Ramie and Sisal. Evaluation parameters: Density, Elongation, Tensile strength and Young’s modulus. Result: Chemical Treatments of Natural Fibre in Sisal is got the first rank whereas is the Hemp is having the Lowest rank.Conclusion: Chemical Treatments of Natural Fibre in Sisal is got the first rank whereas is the Hemp is having the Lowest rank.

Hydrogen and electricity at once: An alkaline-acidic ethanol electroreformer

This study presents the results of an alkaline-acidic ethanol electroreformer producing hydrogen and electricity simultaneously. This is due to the pH gradient between an alkaline anolyte/fuel (1 mol/L ethanol and 4 mol/L KOH) and an acidic catholyte/comburent (1 mol/L H2SO4), separated by a K+-pretreated Nafion® 211 membrane to prevent chemical neutralization, resulting in an extra electromotive force. At 70 °C, the electroreformer delivers a maximum power density of 23 mW cm−2. An increase in the flow rate from 0.17 to 1.12 mL min−1 is also beneficial due to the mass transport enhancement. Finally, over the stability tests for 3 h at 50 °C and a flow rate of 1.12 mL min−1, it is possible to produce H2 at an average rate of 0.218 and 0.267 STP m3 m-2h−1, and an average energy of 0.0877 and 0.0997 kWh m−2 in recirculation and single-pass mode, respectively. The worse performance in the recirculation mode seems to be due to the accumulation of the ethanol electro-oxidation products, resulting in the poisoning of the catalyst surface.

Atomically mixed catalysts on a 3D thin-shell TiO2 for dual-modal chemical detection and neutralization

Herein, an ultrafast flash lamp-driven photothermal design strategy delivers optimal atomically mixed catalysts on a 3D nanostructured metal oxide system. The photocatalytic activity demonstrates selective chemical detection at room temperature and environmental remediation.

Kayıp IoT Verilerinin Makine Öğrenmesi Teknikleri ile Tahmini

Every day, the amount of data generated by industrial applications based on the Internet of Things (IoT) grows. However, data acquired as a result of failures and communication disconnections in IoT devices might be noisy, inaccurate, and incomplete. These issues have become crucial for data production, quality, processing, and analysis. The datasets used in the scope of this study were collected in real-time from the water neutralizer system of Sivas Numune Hospital, which converts medical waste into household waste. Medical liquid wastes in hospitals are exposed to chemical neutralization process by means of pH change with neutralization devices before being transferred to the sewer. In this regard, the monitoring of pH levels in the medical waste neutralization system is crucial for environmental protection. In this aspect, two datasets with varying quantities of missing data were evaluated for the prediction of the PH using the linear regression (LR), support vector machines (SVM), k-nearest neighbor (KNN), random forest (RF), and decision tree (DT) machine learning algorithms. Mean absolute error (MAE), mean squared error (MSE), and root mean square error (RMSE) performance metrics were used to evaluate machine learning algorithms. As a consequence of the analysis, it was determined that the SVM algorithm performed better performance on the two distinct datasets. The result of the evaluation indicates that machine learning algorithms are remarkably efficient at predicting missing pH data.

Preparation of a Dual-Functionalized Acid-Base Macroporous Polymer via High Internal Phase Emulsion Templating as a Reusable Catalyst for One-Pot Deacetalization-Henry Reaction.

A macroporous dual-functional acid–base covalent organic polymer catalyst poly(St-VBC)-NH2-SO3H was prepared using high internal phase emulsion polymerization using vinylbenzyl chloride (VBC), styrene (St), and divinylbenzene (DVB) as substrates toluene as a porogenic solvent, and subsequent modification with ethylenediamine and 1,3-propane sultone. The role of various amounts of toluene as the porogenic solvent as well as the amount of 1,3-propane sultone (different ratio of acid/base sites) on the structure of the prepared materials have been carefully investigated. The prepared materials were characterized by Fourier transform infrared (FT-IR), CHNS elemental analysis, energy-dispersive X-ray (EDX), elemental mapping, field emission scanning electron microscopy (FE-SEM), and thermalgravimetric analysis (TGA). The catalytic activity of the poly(St-VBC)-NH2-SO3H series with different acid/base densities was assessed for one-pot cascade C–C bond-forming reactions involving deacetylation–Henry reactions. The poly(St-VBC)-NH2-SO3H(20) sample bearing 1.82 mmol/g of N (base site) and 1.16 mmol/g (acid site) showed the best catalytic activity. The catalyst demonstrated superior activity compared to the homogeneous catalysts, poly(St-DVB)-SO3H+EDA, poly(St-VBC)-NH2+chlorosulfonic acid, and poly(St-DVB)-SO3H+poly(St-VBC)-NH2 as the catalyst system. The optimized catalyst showed excellent catalytic performance with 100% substrate conversion and 100% yield of the final product in the one-pot production of β-nitrostyrene from benzaldehyde dimethyl acetal under cascade reactions comprising acid-catalyzed deacetalization and base-catalyzed Henry reactions. It was shown that these catalysts were reusable for up to four consecutive runs with a very slight loss of activity. The excellent performance of the catalyst was attributed to the excellent chemical and physical properties of the developed support since it provides an elegant route for preparing site-isolated acid–base dual heterogenized functional groups and preventing their deactivation via chemical neutralization.

Resource Utilization of Acid Mine Drainage (AMD): A Review

Acid mine drainage (AMD) is a typical type of pollution originating from complex oxidation interactions that occur under ambient conditions in abandoned and active mines. AMD has high acidity and contains a high concentration of heavy metals and metalloids, posing a serious threat to ecological systems and human health. Over the years, great progress has been made in the prevention and treatment of AMD. Remediation approaches like chemical neutralization precipitation, ion exchange, membrane separation processes, and bioremediation have been extensively reported. Nevertheless, some limitations, such as low efficacy, excessive consumption of chemical reagents, and secondary contamination restrict the application of these technologies. The aim of this review was to provide updated information on the sustainable treatments that have been engaged in the published literature on the resource utilization of AMD. The recovery and reuse of valuable resources (e.g., clean water, sulfuric acid, and metal ions) from AMD can offset the cost of AMD remediation. Iron oxide particles recovered from AMD can be applied as adsorbents for the removal of pollutants from wastewater and for the fabrication of effective catalysts for heterogeneous Fenton reactions. The application of AMD in beneficiation fields, such as activating pyrite and chalcopyrite flotation, regulating pulp pH, and leaching copper-bearing waste rock, provides easy access to the innovative utilization of AMD. A review such as this will help researchers understand the progress in research, and identify the strengths and weaknesses of each treatment technology, which can help shape the direction of future research in this area.

Unique Step‐Scheme Heterojunction Photoelectrodes for Dual‐Utilization of Light and Chemical Neutralization Energy in Switchable Dual‐Mode Batteries

AbstractHere, a unique step‐scheme (S‐scheme) heterojunction array involving C4N and aligned TiO2 nanorods, namely C4N@TiO2NR, is explored as an advanced photoelectrode for developing an innovative acid–base/Zn–air hybrid cell capable of harvesting light and chemical neutralization energy (CNE) in one integrated system to boost the charge/discharge performance. The properly staggered band arrangement with a built‐in electric field in C4N@TiO2NR induces an S‐type charge migration path to ensure superior redox ability of photogenerated carriers with efficient spatial separation. This coupled with the structural merits of 3D hierarchical arrays enables remarkable photocurrent response and facilitates oxygen evolution kinetics upon irradiation. Paring this heterojunction photoelectrode with an alkaline Zn electrode and an acidic air electrode produces a light and CNE dual‐assisted cell with two switchable modes of light‐assisted acid‐base/air battery (LABAB) and acid‐base battery (LAB). By capturing light during charge and CNE during discharge, LABAB breaks the limit of the equilibrium potential (1.65 V) of conventional Zn–air batteries (ZABs) to deliver impressive charge/discharge voltages of 0.43/2.02 and 0.87/1.86 V at 0.1 and 10 mA cm−2, superior to all reported ZABs. respectively. When LABAB is switched to LAB, it can harvest light and CNE simultaneously to afford markedly increased output voltage relative to common acid–base batteries.

Evolution of mineral phase in the chemical neutralization process of Mn dominated acid mine drainage under different aeration conditions

Chemical neutralization is extensively used in the treatment of acid mine drainage, and the removal of manganese (Mn) is the limiting process for meeting the discharge standards. The formation of Mn-containing precipitates is the main removal mechanism in the neutralization process. This study compared the formation of Mn-containing precipitates under aeration and mechanical stirring conditions, and the effect of aeration rates was also studied. In the aeration-stirring group, the precipitate was composed of hausmannite (Mn3O4), bixbyite (Mn2O3) and rhodochrosite (MnCO3). In addition, Mn(OH)2 was detected in the mechanically stirred group. The results show that the Mn3O4 content in the precipitate increased significantly under aeration conditions and reached a maximum value of 71.9% when the aeration rate was 66.90 L/min. Its content decreased to 54.0% when the aeration rate was increased to 133.80 L/min. The MnCO3 content increased with an increase in the aeration rate and reached a maximum value of 27.3% at an aeration rate of 133.80 L/min. The scanning electron microscopy images revealed that the generated lamellar rhodochrosite (MnCO3) could wrap MnOx and hinder the formation of Mn3O4. This was also verified by the Mn average oxidized state (MnAOS) of the groups. Based on the experimental and calculation results, MnO2 was formed under acidic conditions, and Mn3O4 and Mn2O3 appeared with an increase in the pH level. Meanwhile, the Mn (III) and Mn (IV) oxides are intermediates that were converted into low valance manganese oxides through autocatalysis.

Modified chemical mineralization-alkali neutralization technology: Mineralization behavior at high iron concentrations and its application in sulfur acid spent pickling solution

Mineralization coupled with neutralization is a dual-function technology for disposing acidic iron-rich waters, which can recover the valuable iron in the form of secondary mineral and concurrently purify the wastewater. In this study, a modified technology for treating high Fe wastewater (sulfur acid spent pickling liquor, 62 g Fe/L) was proposed based on the specific investigation of the mineralization behaviors in Fe concentration range of 20–70 g/L. Results showed that high SO42−/Fe2+ molar ratio (> 2.0) tended to trigger gelation phenomena at Fe concentrations above 30 g/L. Fe specie distribution suggested that the insufficient polymerization among Fe-OH complexes might be responsible for the gelation phenomena, since the strong Fe-SO4 coordination almost completely suppressed the Fex(OH)y(3x-y)+ form (a general terms of Fe3+ hydrolysates and their polymers). Modified mineralization strategies were proposed, including pretreatment with dilution or BaCl2/CaCl2 precipitation, of which CaCl2 pretreatment was a versatile and low-cost method. Following CaCl2 pretreatment, chemical mineralization converted above 90% of iron into secondary mineral, which therefore drastically reduced the alkali consumption (from 164.2 g/L to 1.4 g/L) and sludge yield (from 328.1 g/L to 2.4 g/L) in subsequent neutralization treatment. The resultant mineral was identified as schwertmannite, and exhibited efficient adsorption capacity toward arsenite (364.2 mg/g). The modified chemical mineralization-alkaline neutralization is a cost-effective technology for the treatment of the acidic iron-rich waters. In practical applications, several regulating strategies should be further explored to improve the mineral purity, and the mineralization conditions must be optimized according to the Fe and SO42− concentrations in wastewater.

A computational framework to simulate the thermochemical process during thermochemical ablation of biological tissues

Thermochemical ablation (TCA) is a thermal ablation therapy that utilises heat released from acid-base neutralisation reaction to destroy tumours. This procedure is a promising low-cost solution to existing thermal ablation treatments such as radiofrequency ablation (RFA) and microwave ablation (MWA). Studies have demonstrated that TCA can produce thermal damage that is on par with RFA and MWA when employed properly. Nevertheless, TCA remains a concept that is tested only in a few animal trials due to the risks involved as the result of uncontrolled infusion and incomplete acid-base reaction. In this study, a computational framework that simulates the thermochemical process of TCA is developed. The proposed framework consists of three physics, namely chemical flow, neutralisation reaction and heat transfer. An important parameter in the TCA framework is the neutralisation reaction rate constant, which has values in the order of 108 m3/(mol⋅s). The present study will demonstrate that since the rate constant impacts only the rate and direction of the reaction but has little influence on the extent of reaction, it is possible to replicate the thermochemical process of TCA by employing significantly smaller values of rate constant that are numerically tractable. Comparisons of the numerical results against experimental studies from the literature supports this. The aim of this framework is for researchers to advance and develop TCA to gain an in-depth understanding of the fundamental mechanisms of TCA and to develop a safe treatment protocol of TCA in the hope of advancing TCA into clinical trials.

Acid Mine Drainage Treatment Using a Process Train with Laterite Mine Waste, Concrete Waste, and Limestone as Treatment Media

Without treatment, the harmful effects of acid mine drainage (AMD) lead to the destruction of surrounding ecosystems, including serious health impacts to affected communities. Active methods, like chemical neutralization, are the most widely used approach to AMD management. However, these techniques require constant inputs of energy, chemicals, and manpower, which become unsustainable in the long-term. One promising and sustainable alternative for AMD management is to use passive treatment systems with locally available and waste-derived alkalinity-generating materials. In this study, the treatment of synthetic AMD with laterite mine waste (LMW), concrete waste, and limestone in a successive process train was elucidated, and the optimal process train configuration was determined. Six full factorial analyses were performed following a constant ratio of 0.75 mL AMD/g media with a 15-min retention time. The evolution of the pH, redox potential (Eh), total dissolved solids (TDS), heavy metals concentration, and sulfates concentrations were monitored as the basis for evaluating the treatment performance of each run. LMW had the highest metal and sulfates removal, while concrete waste caused the largest pH increase. A ranking system was utilized in which each parameter was normalized based on the Philippine effluent standards (DENR Administrative Order (DAO) 2016–08 and 2021–19). Run 4 (Limestone-LMW-Concrete waste) showed the best performance, that is, the pH increased from 1.35 to 8.08 and removed 39% Fe, 94% Ni, 72% Al, and 52% sulfate. With this, the process train is more effective to treat AMD, and the order of the media in treatment is significant.