Ferric Salts Research Articles

Aquatic invasive plant biomass-derived magnetic porous biochar prepared by sequential carbonization and coprecipitation for diethyl phthalate removal from water

Low-cost multifunctional sorbents are urgently needed, especially for the treatment of emerging pollutants that are widely distributed in various water environments. This work transformed an aquatic invasive plant, Pistia stratotes, into magnetic porous biochars (P-MPBs) based on a proposed strategy involving sequential carbonization to increase porosity and subsequent coprecipitation with ferric salts. Both the porous structure (specific surface area of up to 996.86 m2/g) and high Fe3O4 loading (saturation magnetization of up to 23.48 emu/g) were maintained. A typical plasticizer, diethyl phthalate (DEP), was selected as a model emerging organic pollutant, and the sorption quantity of the P-MPBs reached 490.04 mg g−1, which is much higher than that of many reported sorbents, especially magnetic sorbents. P-MPBs can be reused multiple times due to their excellent separation characteristics and stable structure. On the basis of kinetics and isotherm analysis, multilayer sorption, including pore filling, hydrogen bonding, π–π stacking, and partitioning, was the main DEP sorption process for the P-MPBs. Our study suggested that the proposed method could be promising and inspiring for the transformation of biowaste into excellent magnetic porous biochar that is recyclable and highly efficient at removing pollutants in water.

Magnetic metal-organic frameworks as sensitive aptasensors for coronavirus spike protein

Electrochemical biosensors, known for their low cost, sensitivity, selectivity, and miniaturization capabilities, are ideal for point-of-care devices. The magnetic metal-organic framework (MMOF), synthesized using the in-situ growth method, consists of ferric salt, magnetic nanoparticles, histidine, and benzene tetracarboxylic acid. MMOF was sequentially modified with aptamer-biotin and streptavidin-horseradish peroxidase, serving as a detector for spike protein and a transducer converting electrochemical signals using H2O2-hydroquinone on a screen-printed electrode. MMOF facilitates easy washing and homogeneous deposition on the working electrode with a magnet, enhancing sensitivity and reducing noise. The physical and electrochemical properties of the modified MMOFs were thoroughly characterized using various analytical techniques. The aptasensors' performance achieved a detection limit of 6 pM for voltammetry and 5.12 pM for impedance spectroscopy in human serum samples. This cost-effective, portable MMOF platform is suitable for rapid point-of-care testing for SARS-CoV-2 spike proteins.

In situ construction of iron-rich metal-organic frameworks on wool surface for enhanced flame retardancy and low smoke generation

The incorporation of metal-organic frameworks (MOFs) on textile materials to enhance flame retardancy is of interest and challenge. In this study, an iron-rich MOF (Fe-MOF) was constructed in situ on wool fabric surface through the alternating assembly of ferric metal salt and the carboxylic acid ligand 1,3,5-benzenetricarboxylic acid. The surface morphology, flame retardancy, smoke and heat release performance, thermal stability, and flame-retardant mechanism of the Fe-MOF coated wool fabric were investigated. Square-shaped crystals were observed on the coated wool fabric, indicating successful construction of Fe-MOF on the wool surface. The coated wool fabric with an add-on of 6.8% exhibited excellent flame retardancy, as evidenced by its self-extinguishing ability during the vertical burning test and a significantly enhanced limiting oxygen index of 32.6%. Moreover, the coated wool fabric demonstrated a remarkable reduction in heat and smoke production of 23.8% and 68.4%, respectively, indicating enhanced fire safety. The analysis of char residue, including thermal stability, surface morphology, iron content, and graphitization degree, supported the formation of ferric oxides as a protective layer, contributing to the improved flame retardancy of the Fe-MOF coated wool in the condensed phase. The in situ construction of Fe-MOF on wool macromolecules offers a promising and innovative approach for developing nonhalogen and nonphosphorus flame-retardant systems.

Haem iron versus ferrous iron salts to treat iron deficiency anaemia in Gambian children: protocol for randomised controlled trial {1}

BackgroundThe World Health Organization recommends universal iron supplementation for children aged 6–23 months in countries where anaemia is seen in over 40% of the population. Conventional ferrous salts have low efficacy due to low oral absorption in children with inflammation. Haem iron is more bioavailable, and its absorption may not be decreased by inflammation. This study aims to compare daily supplementation with haem iron versus ferrous sulphate on haemoglobin concentration and serum ferritin concentration after 12 weeks of supplementation.MethodsThis will be a two-arm, randomised controlled trial. Gambian children aged 6–12 months with anaemia will be recruited within a predefined geographical area and recruited by trained field workers. Eligible participants will be individually randomised using a 1:1 ratio within permuted blocks to daily supplementation for 12 weeks with either 10.0 mg of elemental iron as haem or ferrous sulphate. Safety outcomes such as diarrhoea and infection-related adverse events will be assessed daily by the clinical team (see Bah et al. Additional file 4_Adverse event eCRF). Linear regression will be used to analyse continuous outcomes, with log transformation to normalise residuals as needed. Binary outcomes will be analysed by binomial regression or logistic regression, Primary analysis will be by modified intention-to-treat (i.e., those randomised and who ingested at least one supplement dose of iron), with multiple imputations to replace missing data. Effect estimates will be adjusted for baseline covariates (C-reactive protein, alpha-1-acid glycoprotein, haemoglobin, ferritin, soluble transferrin receptor).DiscussionThis study will determine if therapeutic supplementation with haem iron is more efficacious than with conventional ferrous sulphate in enhancing haemoglobin and ferritin concentrations in anaemic children aged 6–12 months.Trial registrationPan African Clinical Trial Registry PACTR202210523178727

Oral iron supplementation: new formulations, old questions.

Iron deficiency anemia and pre-anemic iron deficiency are the most frequent pathologies. The first line of treatment involves oral iron supplementation. The simplest, least expensive, and most frequently prescribed drug is ferrous sulfate, while other ferrous salts and ferric complexes with polysaccharides or succinylated milk proteins are also widely used. In recent years, novel iron formulations have been developed, such as the lipophilic iron donor ferric maltol, or nanoparticle encapsulated sucrosomial® iron. Oral iron supplementation is usually efficacious in correcting iron deficiency anemia and replenishing iron stores but causes gastrointestinal side effects that reduce compliance. When oral iron supplementation is contraindicated, intravenous iron therapy can rapidly achieve therapeutic targets without gastrointestinal complications. Herein, we critically review literature on relative efficacy and tolerability of currently available oral iron supplements, and summarize recent data on optimal dosage and frequency.

Pemanfaatan Lumpur Lapindo sebagai Sumber Silika Magnetik untuk Adsorpsi Tumpahan Crude Palm Oil

In this paper, synthesis of silica magnetite adsorbent has been carried out from Lapindo Mud silica and magnetite (Fe3O4) using the template Cetyltrimethylammonium bromide (CTAB) through a microemulsion process. This research aims to determine the adsorption ability of magnetic silica material as an adsorbent for Crude Palm Oil (CPO) with varying contact times of 10, 20, 30, 60, 90 minutes and an adsorbate concentration of 0,2, 0,4, 0,6, 0,8 and 1 gram. Silica is obtained from Lapindo Mud extraction using the acid leaching method using HCl. Magnetite was prepared by mixing ferric chloride and ferrous chloride salts with an alkaline base. Synthesis of magnetic silica adsorbent using CTAB and 1-butanol as a surfactant and co-surfactant, respectively. The characterization results from FTIR and SEM-EDX data identified the presence of silanol (Si-OH) and Fe-O groups, magnetic silica adsorbent showed an irregular morphological pattern, the size tended to be heterogeneous, contained Fe, O and Si elements. The XRD results show that there are peaks in the (200), (311) and (440) planes, the GSA results show that the pore surface area is 37.048 m2/g, the total pore volume is 0.321 cm3/g and the pore diameter is 33.907 nm, which indicates that the pores have a mesoporous structure. Based on this research, the optimum contact time is 60 minutes with adsorption kinetics following the pseudo-second order and Langmuir isotherm with an adsorption capacity of 1.76 mg/g.

Treatment of chromium (VI) waste solutions with clay-based adsorbents after reduction with acid mine drainage

South Africa has one of the largest Cr-related industries in the world and generates large amounts of Cr-containing smelter dusts. It is normal practice to scrub Cr from the furnace off-gas in water, and to recover the Cr by adsorption, followed by recycling of the loaded adsorbent into the furnace. A study was conducted to find a low-cost adsorbent that is capable of removing sufficient Cr from the solutions generated by scrubbing. The test work focused on the evaluation of different clay minerals (attapulgite, bentonite, and kaolinite) as adsorbents for Cr. Cr(VI) could only be adsorbed after prereduction with e.g. ascorbic acid (ASA). An 80% removal of Cr(VI) could be achieved from a solution containing 20 mg/L Cr using bentonite clay after reduction with ASA. Attapulgite and kaolinite adsorbed less than 55% Cr after reduction with ASA. Both ASA and ferrous salts were found to be suitable reducing agents. The use of acid mine drainage (AMD) was also investigated as a low-cost alternative reducing agent, as AMD usually contains iron. The Cr(VI) reduction potential of the AMD was determined by redox titration against a solution containing 50 mg/L Cr(VI). Studies show that AMD can potentially be used as a reducing agent in a Cr removal process if it is available on site.

Enhanced dewatering extent of sludge by Fe3O4-driven heterogeneous Fenton

Homogeneous Fenton (Fe2+/H2O2) serves as a high-efficiency conditioning method for sludge dewatering due to the generation of strong oxidizing hydroxyl radicals (OH). However, high dose of ferric salts produces iron-rich dewatered sludge and decrease sludge organic matters, which will not be conducive to the subsequent disposal and reutilization. Considering advantages of Fe3O4 as heterogeneous Fenton catalyst, Fe3O4-activated H2O2 (Fe3O4 + H2O2) in this study was adopted to improve sludge deep-dewatering. Reduction efficiency of the bound water (71.3 %) after Fe3O4 + H2O2 treatment (after a reaction time of 30 min) were much higher than those in the Fe2++H2O2 treatment. Especially, the moisture content of treated sludge cake by Fe3O4 + H2O2 remarkably decreased from 86.4 % to 61.3 %. Improvement mechanism of sludge dewatering after Fe3O4 + H2O2 treatment mainly included electrostatic neutralization, reactive radical oxidation, and skeleton building by analysis of contribution factors. The generation of H+ in acidification could neutralize the negatively charged compounds to promote sludge hydrophobicity. Meanwhile reactive radicals generated from Fe3O4 + H2O2 destroyed sludge extracellular polymeric substances and cell structure to release intracellular water. Furthermore, Fe3O4 as a skeleton builder could reconstruct destructive sludge flocs and form new dewatering channels. Finally, low Fe leaching content and recoverability of Fe3O4 effectively will decrease environmental implication.

IronIII-catalyzed asymmetric inverse-electron-demand hetero-Diels-Alder reaction of dioxopyrrolidines with simple olefins.

The asymmetric catalytic inverse-electron-demand hetero-Diels-Alder reaction of dioxopyrrolidines with a variety of simple olefins has been accomplished, significantly expanding the applicability of this cyclization to both cyclic hetero-dienes and dienophiles. A new type of strong Lewis acid catalyst of ferric salt enables the LUMO activation of dioxopyrrolidines via formation of cationic species, this method yields a range of bicyclic dihydropyran derivatives with exceptional outcomes, including high yields (up to 99%), diastereoselectivity (up to 99 : 1) and enantioselectivity (up to 99% ee) under mild conditions. This facile protocol was available for the late-stage modification of several bioactive molecules and transformation into macrocycle molecules as well. The origins of enantioselectivity were elucidated based on control experiments.

Comparison of Anion-Exchange Membranes for Diffusion Dialysis of Mixtures of Acids and Their Iron Salts.

This study presents the possibility of using diffusion dialysis for the separation of inorganic acids (hydrochloric, nitric, and hydrofluoric) and their ferric salts whose composition corresponds to that of real spent pickling solutions. At a steady state, the transport properties of three different anion-exchange membranes (Fumasep-FAD, Neosepta-AFN, and Neosepta-AHA) are compared using a continuous counter-current dialyzer. At a constant composition of the solutions (acid concentration 3 mol L-1 and iron concentration 30-40 g L-1), the effects of volumetric liquid flow rates on the transport rate of H+ and Fe3+ ions through the membrane are studied. The dialysis process is characterized by the recovery of acids and the rejection of salts. Furthermore, the values of the dialysis coefficients of acids, iron, and the acid/iron separation factors are calculated and compared. The volumetric flow rates of the inlet streams change in limits from 3 × 10-8 to 6 × 10-8 m3 s-1 (from 3 to 6 L h-1 m-2, relative to the membrane area). A comparison of the tested membranes shows slightly better results for acid recovery, iron rejection, and acid/iron separation factors for the Fumasep-FAD membrane than for the Neosepta-AFN membrane. However, the results obtained show that both of these anion-exchange membranes can be considered good separators for tested mixtures that simulate real spent pickling solutions, and there is a good precondition for using diffusion dialysis for processing these solutions in industrial practice. On the contrary, very low values of acid recovery and the overall dialysis coefficient of acid are found for the Neosepta-AHA membrane in the test range of the volumetric flow rate, and, thus, this membrane is insufficient for the adequate separation of these acids and iron salts.

Biological upcycling of nickel and sulfate as electrocatalyst from electroplating wastewater

Upcycling nickel (Ni) to useful catalyst is an appealing route to realize low-carbon treatment of electroplating wastewater and simultaneously recovering Ni resource, but has been restricted by the needs for costly membranes or consumption of large amount of chemicals in the existing upcycling processes. Herein, a biological upcycling route for synchronous recovery of Ni and sulfate as electrocatalysts, with certain amount of ferric salt (Fe3+) added to tune the product composition, is proposed. Efficient biosynthesis of bio-NiFeS nanoparticles from electroplating wastewater was achieved by harnessing the sulfate reduction and metal detoxification ability of Desulfovibrio vulgaris. The optimal bio-NiFeS, after further annealing at 300 °C, served as an efficient oxygen evolution electrocatalyst, achieving a current density of 10 mA·cm−1 at an overpotential of 247 mV and a Tafel slope of 60.2 mV·dec−1. It exhibited comparable electrocatalytic activity with the chemically-synthesized counterparts and outperformed the commercial RuO2. The feasibility of the biological upcycling approach for treating real Ni-containing electroplating wastewater was also demonstrated, achieving 99.5 % Ni2+removal and 41.0 % SO42− removal and enabling low-cost fabrication of electrocatalyst. Our work paves a new path for sustainable treatment of Ni-containing wastewater and may inspire technology innovations in recycling/ removal of various metal ions.

Coagulation/co-catalytic membrane integrated system for fouling-resistant and efficient water purification

Low-pressure catalytic membranes allow efficient rejection of particulates and simultaneously removing organics pollutant in water, but the accumulation of dissolved organic matters (DOM) on membrane surface, which cover the catalytic sites and cause membrane fouling, challenges their stable operation in practical wastewater treatment. Here we propose a ferric salt-based coagulation/co-catalytic membrane integrated system that can effectively mitigate the detrimental effects of DOM. Ferric salt (Fe3+) serving both as a DOM coagulant to lower the membrane fouling and as a co-catalyst with the membrane-embedded MoS2 nanosheets to drive perxymonosulfate (PMS) activation and pollutant degradation. The membrane functionalized with 2H-phased MoS2 nanosheets showed improved hydrophilicity and fouling resistance relative to the blank polysulfone membrane. Attributed to the DOM coagulation and co-catalytic generation of surface-bound radicals for decontamination at membrane surface, the catalytic membrane/PMS/ Fe3+ system showed much less membrane fouling and 2.6 times higher pollutant degradation rate in wastewater treatment than the catalytic membrane alone. Our work imply a great potential of coagulation/co-catalytic membrane integrated system for water purification application.

Comparative Analysis of Degradation of Pristine Nafion and Catalyst Coated Membrane Subjected to Ex-Situ Fenton's Test Approach

Polyfluorinated sulfonic –acid ionomer membranes (e.g Nafion) are extensively used today as the benchmark materials for the electrolyte membrane in PEM water electrolysis. It is broadly accepted that the state of the health of PFSA membranes are adversely impacted by the chemical degradation occured during operation of PEMWE. The crossover gases on the catalytic surface generate Hydrogen Peroxide which is homolytically or in the presence of ferrous salts produce reactive oxygen species like hydroperoxyl (HO.) and hydroxyl (HO.) radicals. These radicals attack the ionomer subsequently leading to chain scission, unzipping and loss of functional groups and release of HF in the effluent water.Other than Fe3+, several transition metal ions Cu2+, Ni2+, Ti3+, Cu+, can poison the membrane significantly. The fact that membrane degradation is accelerated owing to introduction of ferrous ions is fervently implemented in ex-situ degradation tests (known as Fentons tests) to evaluate the durability of membrane materials.This work depicts a systematic investigation of degradation of pristine Nafion and catalyst coated Nafion membrane using a Fentons accelerated aging experiment. The durability of Nafion 117 and catalyst coated Nafion membrane with various counter ions against H2O2 was explored as a degradation factor of polymer electrolyte water electrolyser. Two distinct variations of the experiments were compared : (1) Nafion and CCM were dipped in only hydrogen peroxide solution, (2) Nafion and CCM were exposed to a solution containing ferrous ions and peroxide. Accelerated aging experiments were conducted over 3-7 days. The difference in degradation phenomena with and without Fe ions were evaluated in terms of the fluoride ion release. For both cases, to quantify the effect of water activity in Nafion and CCM chemical structure on both water diffusion and interfacial transport, pulse field gradient spin echo nuclear magnetic resonance (PFGSE-NMR) technique has been employed. Furthermore the equivalent weight of the Nafion and CCM can vary in presence of aforementioned chemical stressors which can be accurately quantitatively studied by confocal Raman spectroscopy. Morphological characteristic before and after aging test was also investigated. Role of H2O2 and ferous ion in mechanical behaviour of Nafion and CCM were also analyzed. The same experiment was repeated for different transition metal ions. This work sheds light on decomposition mechanism of Nafion and CCM in more detail.

Effect of ferric salt addition on UV/electro-chlorine advanced oxidation process

ABSTRACTThis study discussed the effect of ferric salt addition on UV/electro-chlorine advanced oxidation process using a train of electrolytic and UV flow cells with an ozone-free low-pressure mercury vapour lamp (total irradiance:0.60 W at 254 nm). Ferric salt addition enhanced 1,4-dioxane degradation at an electrolytic current of 0.100 A. By contrast, an inhibitory effect of ferric salt addition was observed at a current of 0.500 A. The enhanced accumulation of free chlorine at a current of 0.500 A directly decreased the 1,4-dioxane degradation rate by scavenging reactive radicals like HO˙ and Cl˙. However, at an electrolytic current of 0.100 A, UV irradiance was relatively excessive for electrochemical chlorine production. The excess UV energy enhanced the photoreduction of FeOH2+, followed by the Fenton-type reaction of Fe2+ and HOCl, which produced HO˙ and consumed free chlorine. As a result, the free chlorine concentration decreased, and the reaction efficiency between the reactive radicals and 1,4-dioxane improved. Thus, the addition of ferric salt to a UV/electro-chlorine system is recommended when the UV irradiance in the system is excessive compared to the electrochemical chlorine supply.

Green and sustainable synthesis of iron oxide nanoparticles for synergetic removal of melanoidin from ethanol distillery simulated model wastewater

This study investigates a novel approach for removal of melanoidin using Fenton oxidation process. Melanoidins are the biproducts of Maillard’s reaction involving polysaccharides and amino acids. Wastewater generated by ethanol distilleries utilize molasses, a common ingredient containing melanoidin, which is also toxic and imparts a dark color. Various wastewater treatments techniques are present, among which advanced oxidation processes (AOPs), particularly Fenton oxidation, have proven effective in eliminating melanoidins from wastewater. The novelty in this study is that green synthesized iron oxide nanoparticles (FeO NPs) are used in replacement of ferric salts to enhance the Fenton oxidation process for efficient melanoidin removal. The green synthesis provides stability to FeO NPs. FeO NPs were extensively characterized using techniques like FT-IR, XRD, SEM, and EDX analyses. The analyses confirmed that the FeO NPs exhibited a crystalline structure, with an average size of 21.5 nm. The crucial element of this study is to deploy the FeO NPs to power the Fenton oxidation reaction for melanoidin removal.

Characterization of magnetic FeCo particles with controlled bimetallic composition

In this study, six bimetallic FeCo particles were synthesized via the hydrothermal method, employing hydrazine hydrate as a reducing agent. These particles were synthesized at specific Fe:Co ratios of 1:0, 3:1, 1:1, 1:3, 1:9 and 0:1. The synthetic feeding of Fe:Co is of fundamental importance as it not only modulates the composition of the particles but also exerts control over their structural, morphological, and performance attributes. X-ray diffraction (XRD) analysis revealed that for particles synthesized from pure ferrous salt and pure cobalt salt, the former exhibited a Fe3O4 spinel structure, while the latter presented an hcp-type metallic Co structure. Conversely, for the remaining four Fe:Co synthetic feedings, the structure of FeCo bimetallic alloys exhibited a gradual transformation from an Fe-based bcc structure to a Co-based bcc structure, eventually culminating in a Co-based hcp structure as the Co content increased. Scanning electron microscopy (SEM) images indicated that particles prepared with a Fe:Co feeding ratio of 1:0 and 3:1 manifested as cube-shaped particles with approximate sizes of 200 nm and 100 nm, respectively. Particles synthesized with a 1:1 Fe:Co ratio exhibited pyramid-like shapes accompanied by small spinel structures. In contrast, those prepared with a 3:1 and 9:1 Fe:Co feeding ratio displayed a flower-like morphology with particle sizes around 10 µm, while particles synthesized using pure cobalt salts assumed a palm frond-like appearance. Moreover, the investigation into thermal stability established that FeCo alloy particles exhibited superior resistance to air oxidation when compared to pure Co particles. The magnetic studies indicated that all the particles were paramagnetic materials, with their magnetic properties being contingent on the composition. Notably, the particles synthesized with synthetic feedings of 1:1 and 3:1 exhibited the highest saturation magnetization of 151.80 emu·g−1 and the lowest saturation magnetization of 62.79 emu·g−1, respectively. These findings hold significant promise for the development of stable and finely-tailored magnetic particles with diverse potential applications in technology.

Empowering municipal wastewater treatment: Enhancing particulate organic carbon removal via chemical advanced primary treatment

The present study aimed to determine the physical and chemical parameters in the primary treatment process of municipal wastewater by flocculation processes using natural and synthetic polymers as chemically advanced primary treatment (CAPT). Flocculants like chitosan-based, starch-based, and polyacrylamide were chosen, and their feasibility for preliminary treated (PSTin) and pre-treated WASTEWATER (PSTout) underwent precise investigations applying the batch test setup. Since TSS concentration varies hourly in wastewater treatment plants (WWTP) and significantly affects the required dosage of the flocculants, various samples with TSS concentrations ranging from extremely low (<100 mg L−1) to incredibly high (> 700 mg L−1) were gathered to account for all TSS ranges. Several tests were then performed on the samples to establish the efficacy, optimum dosage, settleability, and filterability of the flocs generated by the polymers. The flocs' morphological characteristics were also analyzed by two-dimensional image analysis (2D-IA). The results showed that PSTin or PSTout can be purified solely with synthetic and environmentally confirmed natural-based polymers readily and efficiently. This concept introduces one-stage flocculation for the primary treatment of municipal wastewater rather than the conventional two stages of coagulation-flocculation, which has been used so far while applying harmful aluminum or ferric salts. The results also revealed that the CAPT system can be enhanced by coupling with a microstrain (MS) to remove nearly all particulate organic carbon in the form of COD or TSS. Exploring a range of biological treatment options in conjunction with the CAPT system revealed a significant reduction in external energy reliance for municipal WWTPs, transferring from roughly 75 % to complete independence. This evolution also enables the efficient production of valuable byproducts such as Hydrogen, Polyhydroxyalkanoates, and Ammonium chloride fertilizers, ultimately empowering municipal WWTPs from energy-dependent facilities into self-sustaining energy sources.

Validation of a simple spectrophotometric method for the rapid determination of salicylates in plasma

IntroductionThe determination of salicylate concentrations constitutes a critical aspect of medical diagnostics, particularly in emergency settings. High-performance liquid chromatography (HPLC) and spectrophotometry are efficient methods commonly utilized for this purpose. In emergency laboratories with limited resources, the validation of a cost-effective and reliable spectrophotometric method for salicylates in plasma becomes imperative. The present study aims to validate such a method, ensuring its applicability in toxicological emergencies within resource-constrained laboratories. Materials and methodsThe proposed spectrophotometric analysis relies on detecting salicylic ions amidst the presence of ferric salts, resulting in the formation of a distinct purple chelate complex. To ascertain the method's credibility, the validation guidelines established by the European Medicines Agency (EMA) were employed as a benchmark. A comprehensive validation process was conducted over a three-day period, with three levels of validation standards being considered. ResultsFollowing the EMA protocol, the spectrophotometric method demonstrated commendable fidelity, accuracy, and linearity over a concentration range of 50 to 500 mg/L. The limit of detection and quantification was found to be 10 and 50 mg/L, respectively, and the correlation coefficient was determined to be R2 = 0.998. However, it is essential to acknowledge that interference with phenothiazines occurred at concentrations ranging from 50 to 100 mg/L. Despite this, the method's average sensitivity remains viable for practical use in cases of poisoning. The accuracy per concentration level proved satisfactory, with relative biases remaining below 15%, and the confidence intervals of mean recovery closely approximating the desired target value of 100%. ConclusionIn conclusion, the presented spectrophotometric method stands out as an economical, straightforward, and user-friendly approach, ideally suited for toxicological emergencies when resources are limited. The method delivers satisfying results, establishing its practical utility in critical medical scenarios. This validated method holds immense promise for emergency laboratories facing resource constraints.

Process intensification of chemical phosphorus removal in a microreaction system

Serious problems including excessive ferric salt dose, high effluent phosphorus concentration and long handling time are encountered for chemical phosphorus removal by ferric salt in batch processes due to poor mixing performance. In this work, we develop a microreaction system to intensify phosphorus removal process using ferric chloride by achieving rapid mixing. Phosphorus residual is remarkably reduced by optimizing mixing-related factors, including flow rate, contacting mode, device structures and flow rate ratio which is justified by CFD simulation. The results show that phosphorus removal performance is not sensitive to flow rate ratio. Phosphorus residual can be lower than 0.20 mg/L at [P]0 = 6 mg/L, pH = 6.0, Fe/P = 1.8 and residence time = 42.8 s. Compared with batch processes, the microreaction system has several advantages including much lower phosphorus residual, lower ferric salt dose, shorter processing time and larger handling capacity. Moreover, a machine learning model is established to predict the device performance with high accuracy.

Ligands regulate the application of Fe(Ⅲ)-ligands on Se(Ⅳ) bioreduction: Electron transfer, metabolism activity and EPS secretion

Ligands influence the performance of Fe(Ⅲ) on pollutant biotreatment by affecting the properties of Fe(Ⅲ), but few studies focused on the effect and mechanism for Fe(Ⅲ)-ligands on Se(Ⅳ) bioreduction. Results showed that 5 mM Fe(Ⅲ)-ligands (ethylenediaminetetraacetic acid ferric sodium salt (Fe(Ⅲ)EDTA) and ferric citrate (Fe(Ⅲ)Cit)) could accelerate 4–5 times of Se(Ⅳ) bioreduction rate by accelerating electron transfer rate, improving metabolism activity and enhancing extracellular polymeric substances (EPS) secretion, while the performance of Fe(Ⅲ)Cit and Fe(Ⅲ)EDTA to accelerate Se(Ⅳ) bioreduction was influenced by ligands. Cyclic voltammetry (CV) results showed that the specific capacitance in BK + Fe(Ⅲ)EDTA was 64.43% higher than BK + Fe(Ⅲ)Cit. But, the adenosine triphosphate (ATP) in BK + Fe(Ⅲ)Cit was 67.29 ％ higher than BK + Fe(Ⅲ)EDTA. Meanwhile, electron transport system activity (ETSA), reduced coenzyme Ⅰ (NADH) and cytochrome c contents in BK + Fe(Ⅲ)Cit were also higher than those in BK + Fe(Ⅲ)EDTA. EPS analysis showed that Fe(Ⅲ)EDTA led to decreased aromatic protein content in EPS, while Fe(Ⅲ)Cit could enhance aromatic protein content in EPS. This study provided a new insight and valuable mechanism for Fe(Ⅲ)-ligands to regulate Se(Ⅳ) bioreduction.