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Graphene oxide (GO) is broadly investigated in the electrochemical field. However, for industrial applications, it still suffer from high pollution, low efficiency, poor production quality, and safety concerns associated with traditional synthesis methods. Herein, guided by theoretical analyses, a new oxygen‐atom‐transfer (OAT) mechanism for periodate oxidizing graphite is revealed, exhibiting controllable reaction activity, strong orbital interaction, and abundant electron transfer. Moreover, a flow chemistry strategy with high mass/heat transfer rates is designed to enhance interlayer diffusion and reaction dynamics between oxidants and graphite, ensuring the efficient synthesis of GO within several minutes. As a result, both low oxygen‐content GO with large size, and high oxygen‐content GO with adequate active sites can be precisely and safely synthesized. Benefitting from the controllability of oxygen content and lateral size, the as‐prepared GO sheets can be facilely assembled into fiber/film electrodes that present high mechanical flexibility, large electrical conductivity, and outstanding electrochemical performance. [ABSTRACT FROM AUTHOR]

The development of appropriate and effective periodate (PI) activation technology is currently a popular research area. This study presents a novel efficient photocatalytic activation approach of PI for pollutant degradation based on carbon nitride (g-C3N4) and visible light (Vis). The results show that the system can remove 92.3% of acid orange 7 (AO7) within 60 min under the g-C3N4/PI/Vis reaction system. The degradation rate constant (kobs) reached 4.08 × 10−2 min−1, which is 4.21, 5.16 times, and 51.3 times higher than that of the g-C3N4/Vis system (9.7 × 10−3 min−1), PI/Vis system (7.9 × 10−3 min−1) and the g-C3N4/PI system (7.96 × 10−4 min−1), respectively. Clearly, the addition of PI significantly enhances the degradation efficiency of AO7 in the system. Additionally, under the same reaction conditions, the presence of PI showed excellent oxidation capacity in the photoactivation process compared with other common oxidants, such as peroxymonosulfate, peroxydisulfate, and H2O2. Moreover, the g-C3N4/PI/Vis system showed excellent removal of AO7 across a wide range of pH levels and in the presence of various anions. Electron paramagnetic resonance (EPR) and quenching experiments suggested that the superoxide anions (•O2−) and singlet oxygen (1O2) dominated in the oxidation of pollutants in the g-C3N4/PI/Vis system. In addition, the catalyst showed relative stability during cyclic testing, although a slight reduction in degradation efficiency was observed. In brief, the g-C3N4/PI/Vis system is highly efficient and environmentally friendly, with significant application potential in wastewater treatment. [ABSTRACT FROM AUTHOR]

The MnO 2 /CN/PI/Vis system demonstrated excellent TC degradation performance due to the synergetic influence of the photothermal effect and the construction of S-scheme heterojunction. The Mn(IV)/Mn(III) redox cycles were prominently accelerated through the construction of MnO 2 /g-C 3 N 4 S-scheme heterojunction. [Display omitted] The MnO 2 /CN S-scheme heterojunctions were prepared using the hydrothermal method, which significantly promoted periodate (PI) activation for the TC removal. Notably, the MnO 2 /CN-0.1 achieved a TC removal rate of 79.7 % within 25 min in the PI/Vis system, which was 1.39 and 3.68 times that of MnO 2 and g-C 3 N 4 , respectively. The improved TC degradation performance could be attributed to the synergetic effect of photothermal effect of MnO 2 and the S-scheme heterojunction. On the basis of the infrared thermography images, the photothermal properties of MnO 2 could increase temperatures of the reaction system, leading to the promotion of the PI activation. The formation of the MnO 2 /CN S-scheme not only effectively suppressed charge recombination, but also facilitated the Mn(IV)/Mn(III) redox cycle within the reaction. Under different pH and anion conditions, the MnO 2 /CN-0.1/PI system exhibited excellent capability in TC removal. Additionally, the toxicity of the degraded solution was evaluated based on the LC-MS test results and the growth experiment of Mung bean seeds. This work put forward an efficient approach on S-scheme photothermal catalysts to achieve efficient utilization of PI on TC degradation, which demonstrates a promising method for photothermal assistance PI activation to remediate the water environment efficiently. [ABSTRACT FROM AUTHOR]

Manganese oxide loaded on activated alumina beads (MnOx/AABs) was prepared by one-pot hydrothermal method and applied to activate periodate (PI) towards the degradation of Rhodamine B (RhB) and other organic dyes. The catalyst was first characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and N2 sorption. Subsequently, the effects of catalyst dosage, oxidant dosage, initial pH as well as co-existing inorganic anion and humic acid on the performance of the MnOx/AABs/PI system were studied. Under optimum conditions (catalyst dosage = 15 beads, PI dosage = 0.2 g/L), the removal efficiency of 50 mg/L RhB reached 99.4%, with a total organic carbon removal efficiency of 51.0%. The removal efficiencies of several other organic dyes were in the range of 70%-95.1%. The leached amount of Mn was measured to be 0.027 mg/L. Mechanism studies revealed that 1O2, IO3⋅ and O2⋅− were identified to be responsible in this reaction system, and 1O2 played a decisive role. In addition, IO4− was converted to IO3− without other toxic products during the degradation process. Reusability test in both the batch and continuous modes showed that the catalyst could be efficiency regenerated by calcination. Combining the results of liquid chromatography-mass spectrometry (LC–MS) and density functional theory calculations, the possible degradation pathway of RhB was proposed. Finally, toxicity evaluation of the degradation products of RhB was performed by theoretical calculations as well as experimental tests with Vigna radiata. [ABSTRACT FROM AUTHOR]

In this study, a potassium ferrate (K2FeO4)-modified biochar (Fe–BC) was prepared and characterized. Afterwards, Fe–BC was applied to activated periodate (PI) to degrade tetracycline (TC), an antibiotic widely used in animal farming. The degradation effects of different systems on TC were compared and the influencing factors were investigated. In addition, several reactive oxygen species (ROS) generated by the Fe–BC/PI system were identified, and TC degradation pathways were analyzed. Moreover, the reuse performance of Fe–BC was evaluated. The results exhibited that the Fe–BC/PI system could remove almost 100% of TC under optimal conditions of [BC] = 1.09 g/L, initial [PI] = 3.29 g/L, and initial [TC] = 20.3 mg/L. Cl−, HCO3−, NO3−, and humic acid inhibited TC degradation to varying degrees in the Fe–BC/PI system due to their quenching effects on ROS. TC was degraded into intermediates and even water and carbon dioxide by the synergistic effect of ROS generated and Fe on the BC surface. Fe–BC was reused four times, and the removal rate of TC was still maintained above 80%, indicating the stable nature of Fe–BC. HIGHLIGHTS Fe–BC with excellent morphology and composition was successfully prepared.; Fe–BC could effectively activate periodate in degrading tetracycline (TC).; The response surface methodology was utilized to determine the optimum conditions.; The reactive oxygen species generated were responsible for TC degradation.;

Abstract To achieve complete elimination of anthropogenic micropollutants in aquatic environments, advanced oxidation processes are intensively researched as remedies and potential advanced purification stages in wastewater treatment facilities. Persalts, like persulfates, percarbonates and periodates, have been investigated as potential accelerators or enhancers of these processes. This short review provides an overview of the efficiency of the persalts demonstrated for the degradation of the seven most frequently occurring pharmaceuticals in the aquatic environment: carbamazepine, ciprofloxacin, diclofenac, ibuprofen, metoprolol, paracetamol and sulfamethoxazole. While persulfates were the most commonly used, all persalts increase the effectiveness of the degradation of the pharmaceutical contaminants by increasing the formation of hydroxyl radicals, especially in the case of sodium percarbonate. Persalts are efficiently activated through UVC irradiation. The generated hydroxyl radicals are the main factor for product formation and hence dominate the chemical structures of the transformation products. From the ecotoxicological perspective, the use of persalts causes little or no hazard, if the conditions are such that acidification can be neglected. While they are transformed to stable anions on reaction, the resulting transformation products of the anthropogenic micropollutants were predicted by quantitative structure activity relation analysis to possess lower ecotoxicity than the initial drugs.

To achieve complete elimination of anthropogenic micropollutants in aquatic environments, advanced oxidation processes are intensively researched as remedies and potential advanced purification stages in wastewater treatment facilities. Persalts, like persulfates, percarbonates and periodates, have been investigated as potential accelerators or enhancers of these processes. This short review provides an overview of the efficiency of the persalts demonstrated for the degradation of the seven most frequently occurring pharmaceuticals in the aquatic environment: carbamazepine, ciprofloxacin, diclofenac, ibuprofen, metoprolol, paracetamol and sulfamethoxazole. While persulfates were the most commonly used, all persalts increase the effectiveness of the degradation of the pharmaceutical contaminants by increasing the formation of hydroxyl radicals, especially in the case of sodium percarbonate. Persalts are efficiently activated through UVC irradiation. The generated hydroxyl radicals are the main factor for product formation and hence dominate the chemical structures of the transformation products. From the ecotoxicological perspective, the use of persalts causes little or no hazard, if the conditions are such that acidification can be neglected. While they are transformed to stable anions on reaction, the resulting transformation products of the anthropogenic micropollutants were predicted by quantitative structure activity relation analysis to possess lower ecotoxicity than the initial drugs. [ABSTRACT FROM AUTHOR]

In recent years, the efficient removal of organic pollutants from wastewater has emerged as a critical area of global research interest. Against this backdrop, an array of innovative technologies for wastewater treatment has been developed. Among numerous advanced oxidation processes (AOPs), periodate (PI), an emerging oxidizing agent in AOPs, has garnered significant attention from researchers. Particularly, the integration of ultrasound (US)-activated PI systems has been recognized as an exceptionally promising approach for the synergistic degradation of organic pollutants in wastewater. In this paper, we conducted a thorough analysis of the mechanisms underlying the degradation of organic pollutants using the US/PI system. Furthermore, we comprehensively delineated the effects of ultrasonic power, periodate concentration, temperature, pH, coexisting inorganic ions, and dissolved organic matter on the removal efficiency of organic pollutants and summarized application cases of the US/PI system for the degradation of different pollutants. Finally, we also offered prospective discussions on the future trajectories of US/PI technology development. [ABSTRACT FROM AUTHOR]

The electrokinetic properties of materials give useful insight into the behavior of surfaces in contact with liquids and other compounds and their quantification is a powerful tool to predict their behavior during further processing and application, especially in textile materials. In this work, we perform a comparative analysis of influence of the two most common selective oxidative protocols for viscose (regenerated cellulose) fabrics on subsequent functionalization with chitosan, and cellulose fabrics’ electrokinetic properties, zeta potential in a pH range of approx. 3–10, and isoelectric point (IEP). For oxidation before deposition of chitosan, sodium periodate and 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO) were used. The content of functional groups in oxidized cellulose fabric (carboxyl and carbonyl groups) was determined by titration methods, while amino functional groups’ availability in samples with chitosan was determined using the CI acid orange 7 dye absorption method. This study reveals that the periodate oxidation (PO) of cellulose is more effective for binding chitosan onto material, which gave rise to higher availability of amino groups onto cellulose/chitosan material, which also influenced the shift in zeta potential curve towards positive values at a pH below 5. Analysis of a relationship between zeta potential increase at pH 4.4 and amino groups’ amount measured using absorption of CI acid orange 7 dye at pH 4.4 revealed dependency that can be fitted linearly or exponentially, with the latter providing the better fit (R2 = 0.75).

Natural pyrite (NP) is an alternative catalyst for wastewater purification via advanced oxidation processes (AOPs). However, the activation performance and mechanism of periodate (PI) by NP have not yet been revealed. Herein, this work examines the activation performance of NP towards PI and its application in the degradation of antibiotic wastewater. Interestingly, 95.69% of chlortetracycline (CTC) was degraded by NP within 20 min via PI activation. Besides, NP shows effective degradation of various pollutants such as rhodamine B (65.81%), sulfamethoxazole (89.04%), and sodium butylxanthate (99.77%) within 20 min. The active species quenching experiment suggested that the active species ∙ OH , IO 3 ∙ , 1O2 and the active complex of PI bonded with NP surface participated in CTC degradation. In addition, Fe(II) on NP surface is the main active site for PI activation, while Sn2− species accelerates the reduction of Fe(III) to Fe(II) and promotes sustained PI activation. This work provides new ideas for the application of NP in environmental pollution control. [ABSTRACT FROM AUTHOR]

As reported, the persistent toxic and harmful pollutant bisphenol A (BPA) from industrial emissions has been consistently found in aquatic environments inhabited by humans. Periodate (PI)-based advanced oxidation processes (AOPs) have been employed to degrade BPA, although activating PI proves more challenging compared to other oxidants. A novel nano iron metal catalyst, sulfided nanoscale iron-nickel bimetallic nanoparticle supported on biocarbon (S-(nFe0-Ni)/BC) was synthesized and utilized to activate PI for the removal of BPA. The morphology, structure, and composition of S-(nFe0-Ni)/BC were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy dispersive spectrometer (SEM–EDS), and fourier-transform infrared spectrum (FTIR). The catalyst demonstrates an excellent ability to activate PI, achieving a BPA removal efficacy of 86.4%, accompanied by a 33% reduction in total organic carbon (TOC) in the {S-(nFe0-Ni)/BC}/PI system. BPA degradation exhibited a significant change at the 5-min mark. In the first stage (0–5 min), nonlinear dynamic fitting research, combined with scavenging experiments, unveiled the competitive degradation of pollutants primarily driven by iodate radical ( IO 3 · ), singlet oxygen 1 O 2 , and hydroxyl radical ( · OH ). The competitive dynamics aligned with the ExpAssoc model. The contribution rates of different active species during the second stage (5–120 min) were calculated. The contributions of main species to BPA removal follow the order of IO 3 · > 1 O 2 > · OH throughout the entire process. The influence of various parameters, such as the dosage of S-(nFe0-Ni)/BC, initial PI concentration, BPA concentration, pH, temperature, and the presence of coexisting anions, was also examined. Finally, a plausible reaction mechanism in the system is proposed, suggesting that the {S-(nFe0-Ni)/BC}/PI system involves a heterogeneous synergistic reaction occurring primarily on the surface of S-(nFe0-Ni)/BC. Therefore, this study proposes a promising approach for PI-based AOPs to degrade organic pollutants, aiming to mitigate the irreversible harm caused by such pollutants to organisms and the environment. [ABSTRACT FROM AUTHOR]

The electrokinetic properties of materials give useful insight into the behavior of surfaces in contact with liquids and other compounds and their quantification is a powerful tool to predict their behavior during further processing and application, especially in textile materials. In this work, we perform a comparative analysis of influence of the two most common selective oxidative protocols for viscose (regenerated cellulose) fabrics on subsequent functionalization with chitosan, and cellulose fabrics' electrokinetic properties, zeta potential in a pH range of approx. 3–10, and isoelectric point (IEP). For oxidation before deposition of chitosan, sodium periodate and 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO) were used. The content of functional groups in oxidized cellulose fabric (carboxyl and carbonyl groups) was determined by titration methods, while amino functional groups' availability in samples with chitosan was determined using the CI acid orange 7 dye absorption method. This study reveals that the periodate oxidation (PO) of cellulose is more effective for binding chitosan onto material, which gave rise to higher availability of amino groups onto cellulose/chitosan material, which also influenced the shift in zeta potential curve towards positive values at a pH below 5. Analysis of a relationship between zeta potential increase at pH 4.4 and amino groups' amount measured using absorption of CI acid orange 7 dye at pH 4.4 revealed dependency that can be fitted linearly or exponentially, with the latter providing the better fit (R2 = 0.75). [ABSTRACT FROM AUTHOR]

The oxidation of cellulose to dialdehyde cellulose (DAC) is a process that has received increased interest during recent years. Herein, kinetic modeling of the reaction with sodium periodate as an oxidizing agent was performed to quantify rate-limiting steps and overall kinetics of the cellulose oxidation reaction. Considering a pseudo-first-order reaction, a general rate expression was derived to elucidate the impact of pH, periodate concentration, and temperature on the oxidation of cellulose and concurrent formation of cellulose degradation products. Experimental concentration profiles were utilized to determine the rate constants for the formation of DAC (k1), degradation constant of cellulose (k2), and degradation of DAC (k3), confirming that the oxidation follows a pseudo-first-order reaction. Notably, the increase in temperature has a more pronounced effect on k1 compared to the influence of IO4− concentration. In contrast, k2 and k3 display minimal changes in response to IO4− concentration but increase significantly with increasing temperature. The kinetic model developed may help with understanding the rate-limiting steps and overall kinetics of the cellulose oxidation reaction, providing valuable information for optimizing the process toward a faster reaction with higher yield of the target product. [ABSTRACT FROM AUTHOR]

Cotton fibers were modified by TEMPO oxidation, sodium periodate oxidation, and sodium chloroacetate etherification to obtain carboxylated cellulose fibers with similar carboxyl content (about 70 mmol/100 g). The characteristics of carboxylated cellulose fibers were analyzed by comparing the morphology, chemical structure, crystallinity, carboxyl content, yield, water retention value, degree of polymerization (DP), and cost. The results showed that etherification and oxidation are both important ways to introduce carboxyl groups into the molecular structure of cellulose. When the carboxyl group with similar content is introduced into cellulose, the three modification methods will encourage a certain degree of cellulose degradation. TEMPO oxidation and sodium periodate oxidation will degrade cellulose more obviously, whereas chloroacetate etherification can obtain a higher yield, DP, and lower cost.

Biochar-activated periodate (PI) is a promising technology toward antibiotic wastewater purification. However, the mechanism of pyrolysis temperature on PI activation efficiency by biochar has not yet been revealed. Herein, this work selected water hyacinth stems as raw materials to prepare biochar with different pyrolysis temperatures (400, 500, 600, and 700 °C), and applied it to degrade tetracycline (TC) wastewater through PI activation. The results show that biochar with a pyrolysis temperature of 700 °C (BC-700) possesses the best TC degradation performance (∼100% within 30 min). Besides, the degradation of TC by BC-700 is less interfered by coexisting anions and water matrix, and exhibits good reusability. Quenching experiments and open circuit voltage tests verified that IO3•, 1O2, and reactive complex BC-PI* are active species involved in TC degradation. In addition, by constructing the relationship between biochar surface properties and degradation rate kobs, it was revealed that the dominant role of pyridinic N in PI adsorption and formation of reactive complexes as well as the promotion of sp2-hybridized carbon in the electron transfer process. This work provides novel insights into the application of biochar in antibiotic wastewater treatment via PI activation. HIGHLIGHTS Biochar derived from water hyacinth stems pyrolyzed at 700 °C exhibited optimal removal of TC via periodate activation.; The radical IO3•, the non-radical 1O2, and the reactive complex BC-PI* are responsible for the degradation of TC.; Pyridinic N plays a dominant role in PI adsorption and formation of reactive complexes as well as the promotion of sp2-hybridized carbon in the electron transfer process.;

The development of appropriate and effective periodate (PI) activation technology is currently a popular research area. This study presents a novel efficient photocatalytic activation approach of PI for pollutant degradation based on carbon nitride (g-C3N4) and visible light (Vis). The results show that the system can remove 92.3% of acid orange 7 (AO7) within 60 min under the g-C3N4/PI/Vis reaction system. The degradation rate constant (kobs) reached 4.08 × 10−2 min−1, which is 4.21, 5.16 times, and 51.3 times higher than that of the g-C3N4/Vis system (9.7 × 10−3 min−1), PI/Vis system (7.9 × 10−3 min−1) and the g-C3N4/PI system (7.96 × 10−4 min−1), respectively. Clearly, the addition of PI significantly enhances the degradation efficiency of AO7 in the system. Additionally, under the same reaction conditions, the presence of PI showed excellent oxidation capacity in the photoactivation process compared with other common oxidants, such as peroxymonosulfate, peroxydisulfate, and H2O2. Moreover, the g-C3N4/PI/Vis system showed excellent removal of AO7 across a wide range of pH levels and in the presence of various anions. Electron paramagnetic resonance (EPR) and quenching experiments suggested that the superoxide anions (•O2−) and singlet oxygen (1O2) dominated in the oxidation of pollutants in the g-C3N4/PI/Vis system. In addition, the catalyst showed relative stability during cyclic testing, although a slight reduction in degradation efficiency was observed. In brief, the g-C3N4/PI/Vis system is highly efficient and environmentally friendly, with significant application potential in wastewater treatment.

In this work, degradation and mineralization of para‐nitrophenol in the aqueous medium by a mixture of two strong oxidants of persulfate and periodate have been studied. To this aim, a photo‐reactor with a volume of 1 L has been used. Optimization and modeling of the process was performed by the response surface methodology. According to the prediction of the model, the process has an ability to remove para‐nitrophenol up to 91.6% in the optimal conditions of para‐nitrophenol initial concentration of 15 mg/L, [KPS] = 50 mg/L, [KPI] = 49.7 mg/L, and pH = 5 after 40 min. Assessment of the mineralization of para‐nitrophenol under optimal conditions showed an efficiency of about 57%, while parallel processes alone (UV and UV/KPS and UV/KPI) showed lower mineralization efficiency. Also, the kinetic study showed that the results were fitted with a pseudo‐first‐order equation with a regression coefficient of 0.97 and rate constant of 0.052 (L/min). Moreover, the electrical energy consumption for the process was calculated as 110.77 (kWh/m3) in the optimum condition. In general, the results of this work showed that the use of the homogeneous hybrid AOP methods increases the efficiency of the mineralization. [ABSTRACT FROM AUTHOR]

The discharge of synthetic dyes into the environment poses a significant threat to both human health and the ecosystem, necessitating the treatment of contaminated water. To generate free radicals for the elimination of Direct Blue 71 (DB71) dye from aqueous solutions, periodate (PI) and chlorine (Cl2) have been employed. In this study, separate activation of PI and Cl2 was achieved using ultraviolet (UV) light. The impact of various operational parameters was investigated, resulting in the complete degradation of the dye within 12 min. The presence of ferrous and copper ions had a minor enhancing effect on the degradation rate in both systems. Scavenging experiments confirmed that HO• and IO3• were the primary agents responsible for DB71 degradation in the UV/PI system, while reactive chlorine radicals played a dominant role in the UV/Cl2 process. In terms of mineralization, application for real wastewater and energy efficiency, the UV/PI system exhibited slightly superior performance compared to the UV/Cl2 system. HIGHLIGHTS UV/chlorine and UV/periodate were compared together for the first time.; A complete degradation of DB71 was achieved in at short time for both processes.; The carboxylic evolution of DB71 degradation was monitored.; A practical study was conducted on real wastewater.;

In recent years, the efficient removal of organic pollutants from wastewater has emerged as a critical area of global research interest. Against this backdrop, an array of innovative technologies for wastewater treatment has been developed. Among numerous advanced oxidation processes (AOPs), periodate (PI), an emerging oxidizing agent in AOPs, has garnered significant attention from researchers. Particularly, the integration of ultrasound (US)-activated PI systems has been recognized as an exceptionally promising approach for the synergistic degradation of organic pollutants in wastewater. In this paper, we conducted a thorough analysis of the mechanisms underlying the degradation of organic pollutants using the US/PI system. Furthermore, we comprehensively delineated the effects of ultrasonic power, periodate concentration, temperature, pH, coexisting inorganic ions, and dissolved organic matter on the removal efficiency of organic pollutants and summarized application cases of the US/PI system for the degradation of different pollutants. Finally, we also offered prospective discussions on the future trajectories of US/PI technology development.

We produced a novel starch derivative in two steps: periodate oxidation to obtain dialdehyde starch (DAS) and conjugation of DAS with lysine in a Maillard-type reaction. Compared to the native tapioca starch, DAS has significantly lower intrinsic viscosity, molecular weight, relative crystallinity, smoothness of granule surface, and swelling power, but higher solubility and light transmittance. When produced using increasing periodate concentrations from 0.05 to 3.0 N, DAS had higher carbonyl contents and swelling powers but lower recovery efficiency, intrinsic viscosity, relative crystallinity, and solubility. When produced from DAS with higher carbonyl contents, the DAS-lysine conjugates had higher degree of lysine conjugation and swelling power but lower intrinsic viscosity, relative crystallinity, granule integrity and paste transparency. This approach of conjugation can be used in slow-release applications, where different amino acids, peptides, or even proteins can be conjugated with DAS, and then cleaved and released in the stomach or other acidic media. [ABSTRACT FROM AUTHOR]

In the present study, the degradation of an azo dye Orange G (OG) by the UV/TiO2/periodate (IO4-) process has been investigated. OG was totally disappears within 10 min by the UV/TiO2/IO4-compared to UV alone, UV/TiO2 or UV/IO4-. A synergistic effect has been obtained when combining the UV/TiO2 and the UV/IO4-systems, resulting in positive interactions between both processes. Experiments conducted with specific hydroxyl radical scavengers, show that despite the inhibition effect observed, complete degradation has been achieved beyond 10 min, demonstrating that the degradation is not only initiated by hydroxyl radical, but also by other reactive entities; the involvement of iodate radical is confirmed with the use of chromium species as a competitor with periodate ions for the photogenerated electron at the conduction band. The operating parameters influencing the degradation process such as initial dye concentration, initial periodate concentration, light intensity/wavelength and initial pH solution have been explored. The presence of inorganic ions such as chloride, bromide, sulphate, carbonate and bicarbonate ions in the irradiated solution show reverse effects depending on the concentration used. The OG degradation in different water matrices is found to be sensitive to the presence of different species and their nature. Chemical oxygen demand (COD) has been partially removed after 10 min of treatment, and then this COD abatement stabilized, indicating the strength of the by-products from dye degradation by the UV/TiO2/IO4- system during the treatment time. The electrical energy consumption is estimated at 2.21kWhm3/Order. The results obtained indicate that the UV/TiO2/IO4- process could be used as a hybrid process to the treatment of dye contaminated water. [ABSTRACT FROM AUTHOR]

Para-nitrophenol (PNP) is a toxic compound widely used in various industries. The release of PNP into the environment not only threatens human health but the ecosystem. Hence, the treatment of contaminated water is necessary. Periodate (PI) is a new oxidant which is used for the generation of free radicals. In the current work, PI was concurrently activated by ultraviolet (UV) and ultrasound (US) to eliminate PNP from aqueous solution. The effects of operating parameters were studied and complete degradation of PNP was obtained in 30 min. The presence of ferrous ions increased the PNP degradation rate. Scavenging experiments confirmed that HO• and IO3• were corresponding agents of the PNP degradation, which the latter had a bold role. The performance of PI/UV/US was examined on real wastewater and the results showed that 70% of total phenol was removed during 60 min. The PNP degradation intermediate was recognized and a pathway of PNP degradation was proposed. Although PI/UV/US process is high energy consuming, its excellent performance can be a rational reason for the scaling up the process. [ABSTRACT FROM AUTHOR]

The photoactivated periodate (UV/IO4−) process is used to investigate the degradation of acid orange 10 (AO10) dye. The photodecomposition of periodate ions produces highly reactive radicals (i.e., •OH, IO3•, and IO4•) that accelerate dye degradation. Increasing the initial concentration of periodate to 3 mM enhances the dye removal rate, but over 3 mM periodate, the degradation rate slows down. On the contrary, increasing initial dye concentrations reduces the degradation performance. pH is the most critical factor in AO10 breakdown. Salts slow down the degradation of the dye. However, UV/IO4− is more efficient in distilled water than natural water. Even at low concentrations, surfactants may affect the dye's decomposition rate. The addition of sucrose reduced the breakdown of AO10. Although tertbutanol is a very effective •OH radical scavenger, it does not affect the dye breakdown even at the highest concentrations. Accordingly, the AO10 degradation is a non-•OH pathway route. According to retrieved data, the photoactivated periodate method eliminated 56.5 and 60.5% of the initial COD after 60 and 120 min of treatment time; therefore, it can be concluded that the UV/IO4− system may treat effluents, especially those containing textile dyes. [ABSTRACT FROM AUTHOR]

The oxidation of cellulose to dialdehyde cellulose (DAC) is a process that has received increased interest during recent years. Herein, kinetic modeling of the reaction with sodium periodate as an oxidizing agent was performed to quantify rate-limiting steps and overall kinetics of the cellulose oxidation reaction. Considering a pseudo-first-order reaction, a general rate expression was derived to elucidate the impact of pH, periodate concentration, and temperature on the oxidation of cellulose and concurrent formation of cellulose degradation products. Experimental concentration profiles were utilized to determine the rate constants for the formation of DAC (k1), degradation constant of cellulose (k2), and degradation of DAC (k3), confirming that the oxidation follows a pseudo-first-order reaction. Notably, the increase in temperature has a more pronounced effect on k1 compared to the influence of IO4− concentration. In contrast, k2 and k3 display minimal changes in response to IO4− concentration but increase significantly with increasing temperature. The kinetic model developed may help with understanding the rate-limiting steps and overall kinetics of the cellulose oxidation reaction, providing valuable information for optimizing the process toward a faster reaction with higher yield of the target product.

The kinetics of oxidation of [Fe(phen)3]2+ by periodate has been studied in CTAB (cetyltrimethylammonium bromide) reverse micelles by changing the parameter W (=[H2O]/[CTAB]) and surfactant CTAB concentration. The reaction shows first order dependence on [Fe(phen)3]2+ and zero order on periodate. The reaction is autocatalytic in aqueous medium but autocatalysis disappears in reverse micellar medium. The pseudo first order rate constant k' decreases with increasing the value of W and at fixed concentration of CTAB and is independent of CTAB concentration. The influence of W is explained on the basis of the unique properties of water pool of reverse micelles. [ABSTRACT FROM AUTHOR]

• Removal efficiency followed the order: α-MnO 2 > γ-MnO 2 > β-MnO 2 > ε-MnO 2 > δ-MnO 2. • α-MnO₂ possessed outstanding activity and durability in activating PI. • Electron-mediated process primarily derived pollutant degradation. • α-MnO₂ could initiate the activation of PI for the α-MnO₂-PI* formation. • Degradation efficiency was associated with the crystal phase and Mn (IV) content. Manganese dioxide (MnO 2), renowned for its abundant natural crystal phases, emerges as a leading catalyst candidate for the degradation of pollutants. The relationship between its crystal phase and catalytic activity, particularly for periodate activation, has remained both ambiguous and contentious. This study delineates the influence of various synthetic MnO 2 phase structures on their capabilities in catalyzing periodate-assisted pollutant oxidation. Five distinct MnO 2 phase structures (α-, β-, γ-, δ-, and ε-MnO₂) were prepared and evaluated to activate periodate and degrade pollutants, following the sequence: α-MnO₂ > γ-MnO₂ > β-MnO₂ > ε-MnO₂ > δ-MnO₂. Through quenching experiments, electron paramagnetic resonance tests, and in situ electrochemical studies, we found an electron transfer-mediated process drive pollutant degradation, facilitated by a highly reactive metastable intermediate complex (MnO₂/PI*). Quantitative structure-activity relationship analysis further indicated that degradation efficiency is strongly associated with both the crystal phase and the Mn (IV) content, highlighting it as a key active site. Moreover, the α-MnO₂ phase demonstrated exceptional recycling stability, enabling an effective pollutant removal in a continuous flow packed-bed reactor for 168 h. Thus, α-MnO₂/PI proved highly effective in mineralizing organic pollutants and reducing their toxicities, highlighting its significant potential for environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • We prepare different metal single-atoms catalysts for degradation of drugs. • Mn-CN+periodate (PI) system can ultrafast degrade drugs. • The role of electron transfer exceeds that of reactive oxygen species in the system. • PI binds to the MnN 3 sites to form the MnN 3 -PI* complexes. • DFT calculations reveal that MnN 3 -PI* complexes control electron transfer pathway. Different transition metal single-atoms may lead to a variety of reaction mechanisms in advanced oxidation processes (AOPs). The transition metal (Fe, Ni and Mn) single-atom C 2 N 3 catalysts were used to degrade acetaminophen (AP) by activating periodate (PI). Mn-CN+PI system can completely remove AP in 2 min, and its rate constant (5.7550 min−1) was 9.37 and 22.69 times higher than that of Ni-CN+PI and Fe-CN+PI. The system showed excellent performance in different influencing factors and micropollutant removal experiments. The recyclable Mn-CN sponge sheet showed good practical application performance in microreactor experiments. Electron paramagnetic resonance, radical quenching, electrochemical experiments, combined with theoretical simulation certified that Mn-CN+PI system was dominated by electron transfer mechanism, which was superior to reactive oxygen species that dominated Ni-CN+PI and Fe-CN+PI systems. The electron transfer-mediated pollutant degradation provides insights into PI-based AOPs, and offers a feasible pathway for micropollutant degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electro-Fe(II) can significantly promote PI to degrade SMX. • Fe(IV)-oxo and 1O 2 as the main reactive species are generated under the E(Fe/C)/PI system in pH=3 and 6.5, respectively. • Density functional theory (DFT) calculations are employed to reveal the differences of catalytic mechanisms in both pH conditions. • SMX degradation intermediates and toxicities are presented through experimental results and DFT calculations. The ferrous species (Fe(II))-periodate (PI) system employs efficient decontamination by generating ferryl species (Fe(IV)-oxo) under acidic pH conditions. However, the mechanisms by which the Fe(II)/PI system operates across a broad pH range remain elusive. In light of the rapid oxidation and consumption of Fe(II) at neutral pH, we developed an electro-Fe(II) system utilizing an iron plate anode to activate PI (E(Fe/C)/PI). Efficient sulfamethoxazole (SMX) degradation was achieved under the E(Fe/C)/PI system across a range of pH values. Quenching and chemical probe experiments revealed a transition from Fe(IV)-oxo to singlet oxygen (1O 2) as the predominant reactive species from acidic to near-neutral pH, respectively. Density functional theory (DFT) calculations indicated that the differences in one-electron transfer capacity and hydrolysis pathways for various protonated Fe(IV)-oxo species underlie the variations in catalytic mechanisms. This study not only enhances the efficiency of the Fe(II)/PI system but also provides a comprehensive understanding of the activation mechanisms at different pH levels. [ABSTRACT FROM AUTHOR]

[Display omitted] • An efficient selective elimination of tetracyclines antibiotics was developed. • The interaction mechanism between tetracyclines and benzoquinone was confirmed. • Periodate exhibited superior degradation efficiency than other oxidants. • Remarkable resistance to natural water substances implied its potential applications. The binding behavior of tetracyclines (TCs) with natural organic matter and the subsequent induction of degradation in advanced oxidation processes has been underestimated. In this study, based on the specific oxidative effects of periodate, the selective degradation of TCs by periodate was achieved with benzoquinone (BQ) that induced poor stability intermediates. The periodate achieved the near complete degradation of TC with a trace concentration of BQ under the alkaline condition, with the k obs at 0.3090 min−1. The degradation experiments for twelve micropollutants revealed that the periodate/BQ system had a considerably efficient degradation only for TCs, and combined with the electron paramagnetic resonance (EPR) analysis, the minor involvement of reactive oxygen species during the degradation process was confirmed. The evident correlation between the observed k obs and the pre-mixing duration of TC with BQ demonstrated the dependence of the degradation process on intermediate generation. Furthermore, theoretical calculations revealed the reaction sites between the TC and BQ; the product identification and energy barrier of 18.94 kcal/mol further confirmed the interaction pathway through the Michael addition reaction. Moreover, based on the narrow energy gap (0.5350 eV) with the intermediate, only the periodate demonstrated efficient degradation of TC under alkaline conditions among the various oxidants. Little toxic iodine species were produced during the reaction, and the system exhibited resistance to natural water substances, such as anions and humic acid, highlighting its potential for application. In conclusion, the interaction mechanisms between TCs and BQ were elucidated in this research, and an efficient approach was proposed for eliminating residual TCs from aquatic environments and selective degradation from wastewater matrices. [ABSTRACT FROM AUTHOR]

[Display omitted] • The generation of active species in GF-PI system exhibits remarkable pH dependency. • No formation of 1O 2 and low concentration of ·OH generation under acid conditions. • ·OH, IO 3 ·, and 1O 2 are the main ROSs for SMX removal under initial pH=7 and 9. • The system performed remarkable stability, anti-interference capabilities, and cost-effectiveness for SMX removal. • The degradation intermediates of SMX are proposed at different initial pH. Although electro-activated periodate (PI) has demonstrated significant efficiency in degrading emerging contaminants (ECs), there has been limited research investigating the pH-dependence of active species generation and pollutant degradation. A graphite felt-based electrochemical system (GF-PI) was chosen to deeply explored. It exhibited significant differences in contaminants removal under different pH conditions. Notably, an interesting result is found that the GF-PI system at pH=3 exhibited exceptional removal performance specifically for phenolic contaminants, such as bisphenol A (BPA) and acetaminophen (ACT), whereas it displayed poor efficiency for other compounds, including sulfamethoxazole (SMX), carbamazepine (CBZ), benzoic acid (BA), and atrazine (ATZ). However, there is no selectivity for contaminants removal in pH=4, 7, and 9 system. The experiment of probe capture and quenching are conducted to thoroughly investigate the variety of reactive oxygen species (ROSs) generated. It has been proven that hypoiodous acid (HOI) is the main active species in the system with pH=3. In addition, the system with pH=4 exhibits the highest degradation efficiency and TOC removal efficiency, despite the low yield of hydroxyl radical (·OH), indicating that the iodate radical (IO 3 ·) plays a pivotal role. Under neutral and alkaline conditions, ·OH, IO 3 ·, and singlet oxygen (1O 2) are the main active species. Moreover, the system exhibits remarkable stability, anti-interference capabilities, and cost-effectiveness, indicating the superiority for treatment of authentic wastewater. Additionally, the degradation intermediates and biotoxicity of SMX are evaluated through multiple measures. A comprehensive understanding of pH is indispensable in electro-activated PI system for treatment of emerging organic contaminants. [ABSTRACT FROM AUTHOR]

[Display omitted] • MnFe 2 O 4 /Biochar (MFB) synergistically enhances pollutant degradation in water. • Stable and recyclable MFB-1:2 degraded tetracycline (TC) despite interferents. • O 2 –•,·1O 2 , IO 3 •, and •OH promoted TC degradation in MFB-1:2/periodate system. • Ecotoxicity of degradation intermediates was assessed by T.E.S.T. • MFB-1:2/periodate is efficient for removing organic matter from freshwater. The periodate (PI)-based advanced oxidation process (AOP) is an economical and energy-saving method for remediating water by degrading pollutants. An efficient system for PI activation was developed by loading manganese ferrite spinel (MnFe 2 O 4) on biochar (BC) through a facile method, affording a metal-oxide MnFe 2 O 4 /BC composite catalyst. The developed system demonstrated significant effectiveness in eliminating various organic pollutants, particularly achieving high removal (5.26 and 2.83 times that of biochar and MnFe 2 O 4 , respectively) and mineralization (49.7 %) of the model pollutant tetracycline hydrochloride (TC) within 30 min. The system exhibited outstanding catalytic performance under various environmental conditions (pH, inorganic salts, humic acid, and real water bodies), as evidenced by quenching experiments and electron paramagnetic resonance (EPR) studies, proving that superoxide radicals (O 2 •-) are the main reactive species for TC degradation in the reaction system, in addition to singlet oxygen (1O 2), iodyl radicals (IO 3 •) and hydroxyl radicals (•OH). Potential pathways for TC degradation in this system were revealed based on density functional theory (DFT) and the ecological toxicity of the intermediates was analyzed through quantitative structure–activity relationship (QSAR) assessment. Analysis of the magnetic hysteresis and cycling stability demonstrated that the composites were stable and could be recycled by applying a magnetic field. This work opens a new pathway for designing efficient PI activators for the selective oxidation of organic pollutants and highlights the potential application of this system in practical wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Photoinduced IO 3 − oxidation mechanisms to IO 4 − on WO 3 were computationally studied. • The first deprotonation from *OH 2 to form *OH is common in O 2 and IO 4 − productions. • After IO 3 − adsorption, the second deprotonation from *OH∙∙∙IO 3 − produces IO 4 −. • Counter Na+ inhibits competitive O 2 evolution but promotes IO 4 − production. • Compared to Li+ and K+, Na+ leads to a higher selectivity for IO 4 − on WO 3. The mechanisms involved in the photoelectrochemical oxidation of iodate (IO 3 −) to metaperiodate (IO 4 −) and H 2 O to O 2 on WO 3 were investigated using density functional theory. The oxygen evolution reaction (OER) included four proton-coupled electron transfer (PCET) steps via H 2 O 2 intermediates. After the first PCET of the rate-limiting step, instead of H 2 O adsorption, IO 3 − was adsorbed and the second PCET step generated IO 4 − species (PI1 mechanism). Although another mechanism, PI2, with the two PCET steps followed by the IO 3 − adsorption was found, IO 4 − was energetically generated via PI1 rather than via PI2. Based on the free energy changes in the PCET steps, alkaline cations such as Li+, Na+, and K+ on WO 3 suppressed the OER process. In addition, Na+ promoted the IO 3 − adsorption and subsequent PCET step of PI1. The computational results verified that using NaIO 3 aqueous solution on WO 3 effectively inhibits OER and facilitates IO 4 − generation, resulting in a higher (lower) selectivity of IO 4 − (O 2) than using LiIO 3 and KIO 3 aqueous solutions. [ABSTRACT FROM AUTHOR]

[Display omitted] • OTC was significantly removed in L-1 T-MoS 2 /PI system. • 1O 2 and •OH played crucial roles in MoS 2 /PI system. • Phase engineering altered electron density of Mo sites and regulated PI activation. • PI adsorption energy on L-1 T-MoS 2 was higher than that on 2H-MoS 2 and H-1 T-MoS 2. • L-1 T-MoS 2 /PTFE membrane unfolded an efficient removal rate (＞85 %) for OTC. MoS 2 -based materials are promising in the field of wastewater treatment. However, the potential application and intrinsic mechanism of MoS 2 -driven periodate (PI) remains unclear. Here, the MoS 2 materials with different 1T/2H ratios, which were characterized by XRD, Raman and XPS were synthesized. The MoS 2 /PI system could signally promote oxytetracycline (OTC) degradation under dark conditions and 1T/2H ratio of MoS 2 has a noticeable effect on the catalytic performance. Specially, the k obs of L-1T-MoS 2 (50% 1T phase) was 1.59 and 3.62 times of H-1T-MoS 2 (∼74% 1T phase) and 2H-MoS 2 (100% 2H phase). The results of quenching experiments, EPR, EIS, I-t and Tafel polarization curves showed that •OH and 1O 2 , rather than O 2 •−, H 2 O 2 , IO 3 •, high-valent oxide oxidation and electron transfer, played important roles in MoS 2 /PI systems. XPS analysis and DFT calculations revealed that Mo was the primary site and phase engineering increased the electron density of Mo sites in MoS 2 , thereby regulating the activation of PI. These results would enrich understandings on phase engineering of MoS 2 to turn its catalytic performance for OTC degradation. [ABSTRACT FROM AUTHOR]

The transmission of antibiotic resistance genes (ARGs) and the propagation of antibiotic resistant bacteria (ARB) threaten public health security and human health, and greener and more efficient disinfection technologies are expected to be discovered for wastewater treatment. In this study, natural pyrite and ascorbic acid (AA) were proposed as environmental-friendly activator and reductant for periodate (PI) activation to inactivate ARB. The disinfection treatment of PI/pyrite/AA system could inactivate 5.62 log ARB within 30 min, and the lower pH and higher PI and natural pyrite dosage could further boost the disinfection efficiency. The 1O 2 and SO 4 •- were demonstrated to be crucial for the inactivation of ARB in PI/pyrite/AA system. The disinfection process destroyed the morphological structure of ARB, inducing oxidative stress and stimulating the antioxidant system. The PI/pyrite/AA system effectively reduced the intracellular and extracellular DNA concentration and ARGs abundance, inhibiting the propagation of ARGs. The presence of AA facilitated the activation of PI with natural pyrite and significantly increased the concentration of Fe2+ in solution. The reusability of natural pyrite, the safety of the disinfection by-products and the inhibition of ARB regeneration indicated the application potential of PI/pyrite/AA system in wastewater disinfection. [Display omitted] • PI/pyrite/AA system could efficiently inactivate 5.62 log ARB within 30 min. • The used natural pyrite was still effective for PI activation to inactivate ARB. • 1O 2 made a major contribution to the inactivation of ARB by PI/pyrite/AA system. • The PI/pyrite/AA system inhibited regeneration of ARB and transmission of ARGs. • The PI/pyrite/AA system is a green, low-cost and efficient disinfection process. [ABSTRACT FROM AUTHOR]

Periodate (PI)-based advanced oxidation processes have gained increasing interest. This study for the first time elevates the light-activation capacity of PI by using far UVC at 222 nm (UV 222 /PI) without extra chemical inputs. The effectiveness and the underlying mechanisms of UV 222 /PI for the remediation of micropollutants were studied by selecting atenolol (ATL) as a representative. PI possessed a high molar absorption coefficient of 9480–6120 M−1 cm−1 at 222 nm in the pH range of 5.0–9.0, and it was rapidly decomposed by UV 222 with first-order rate constants of 0.0055 to 0.002 s−1. ATL and the six other organic compounds were effectively degraded by the UV 222 /PI process under different conditions with the fluence-based rate constants generally two to hundred times higher than by UVA photolysis. Hydroxyl radical and ozone were confirmed as the major contributors to ATL degradation, while direct photolysis also played a role at higher pH or lower PI dosages. Degradation pathways of ATL were proposed including hydroxylation, demethylation, and oxidation. The high energy efficiency of the UV 222 /PI process was also confirmed. This study provides a cost-effective and convenient approach to enhance PI light-response activity for the treatment of micropollutants. [Display omitted] • The quantum yields and molar absorption coefficient of PI at 222 nm are reported for the first time. • •OH and O 3 are the dominant oxidants in the UV 222 /PI process. • The contribution to the degradation of ATL followed the order of •OH > O 3 > direct photolysis. • Hydroxylation, demethylation, and oxidation were the main pathways for atenolol degradation. • The study offers a convenient, efficient, and cost-effective activation approach of PI. [ABSTRACT FROM AUTHOR]

• Nickel–manganese sulfide grown on Ni foam was developed via a hydrothermal method. • NiMnS@NF possessed outstanding activity and durability in activating PI. • NiMnS@NF can initiate the activation of PI for the NiMnS@NF–PI* formation. • Superoxide radicals played a cooperative role in removal of organic contaminants. • NF's monolithic nature simplified the catalyst recycling process. Nickel–manganese bimetallic sulfide microparticles in situ grown on Ni foam (NiMnS@NF) with controllable morphology and composition were developed via a hydrothermal method to boost potassium periodate activation for oxidation of multiple micropollutants. Benefiting from the unique morphology and structure, along with a synergistic effect of different components, the optimized NiMnS@NF exhibits outstanding performance and durability in potassium periodate activation, surpassing other oxidant systems (e.g., H 2 O 2 , peroxydisulfate, and peroxymonosulfate). Electron spin resonance analysis, scavenging tests, electrochemical analysis, and galvanic oxidation tests unveiled that NiMnS@NF can initiate the activation of potassium periodate, resulting in the formation of high-potential metastable intermediates (NiMnS@NF–potassium periodate*). Additionally, superoxide radical anions play a cooperative role in organic elimination. The experimental results further indicate that the synergy among Mn/Ni and S induces a local charge redistribution, improving electron transfer capability and Mn(II)/Mn(III)/Mn(IV) and Ni(II)/Ni(III) redox reactions. This work proposes a feasible and efficient monolithic catalyst for environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn(II) can activate PI to efficiently degrade sulfadiazine in water. • The Mn(II)/PI system is a non-radical process dominated by electron transfer. • The generated MnO 2 -PI complex plays an important role in SDZ degradation. • Stable iodates are the main iodine species in the Mn (II)/PI system. The present study investigated the mechanism of manganese ion (Mn(II))-activated periodate (PI) for rapid removal of sulfadiazine (SDZ). The Mn(II)/PI system showed excellent SDZ degradation results with 99.8 % degradation efficiency within 2 min at pH = 5.5. Mechanism study reveals that the degradation of SDZ in the Mn(II)/PI system takes place mainly through an electron transfer process. Mn(II) can be oxidized by PI to formed the in-situ MnO 2 , followed by the generation of MnO 2 -PI complex. Electrochemical methods have confirmed that the generated MnO 2 -PI complex significantly contributes to the degradation of pollutants. MnO 2 -PI mediates the transfer of electrons from SDZ to PI surface through surface vacancies, thereby achieving efficient degradation of pollutants. p -methoxyphenyl sulfone (PMSO) is used as a probe compound, and almost 90 % of PMSO is converted into PMSO 2 in the Mn(II)/PI/SDZ system, manifesting that excessive PI may oxidize active Mn(IV) to Mn(V). And the generated Mn(V) also contributes to the SDZ degradation. The SDZ degradation pathway is proposed and the transformation of iodine species is detected. The final iodine species in the system are iodate. The chloride culture experiment has confirmed that the production of organic iodine is very low, indicating no significant health risks. This study reveals mechanism of periodate-based process, providing theoretical and technical implementation guidelines of periodate in water treatment. [ABSTRACT FROM AUTHOR]

• Microcystis aeruginosa could be inactivated by periodate activation with sunlight. • ·OH, IO 3 ·, and IO 4 · radicals contributed to algae inactivation in PI-SSL system. • The released microcystin-LR could be synchronously degraded in PI-SSL system. • PI-SSL system could inactivate algae in real waters and a continuous-flow reactor. • Natural sunlight could activate PI to achieve efficient algae inactivation. Harmful algal blooms pose tremendous threats to ecological safety and human health. In this study, simulated solar light (SSL) irradiation was used to activate periodate (PI) for the inactivation of Microcystis aeruginosa and degradation of microcystin-LR (MC-LR). We found that PI-SSL system could effectively inactivate 5 × 106 cells·mL−1 algal cells below the limit of detection within 180 min. ·OH and iodine (IO 3 · and IO 4 ·) radicals generated in PI-SSL system could rupture cell membranes, releasing intracellular substances including MC-LR into the reaction system. However, the released MC-LR could be degraded into non-toxic small molecules via hydroxylation and ring cleavage processes in PI-SSL system, reducing their environmental risks. High algae inactivation performance of PI-SSL system in solution with a wide pH range (3–9), with the coexisting anions (Cl−, NO 3 − and SO 4 2−) and the copresence of natural organic matters (humic acid and fulvic acid), real water (lake water and river water), as well as in continuous-flow reactor (14 h) were also achieved. In addition, under natural sunlight irradiation, effective algae inactivation could also be achieved in an enlarged reactor (1 L). Overall, our study showed that PI-SSL system could avoid the inference by the background substances and could be employed as a feasible technique to treat algal bloom water. [Display omitted] [ABSTRACT FROM AUTHOR]

The potential of periodate (PI) in sludge anaerobic digestion is not tapped, although it has recently attracted great research interest in organic contaminants removal and pathogens inactivation in wastewater treatment. This is the first work to demonstrate significant improvement in methane generation from waste activated sludge (WAS) with PI pretreatment and to provide underlying mechanisms. Biochemical methane potential tests indicated that methane yield enhanced from 100.2 to 146.3 L per kg VS (VS, volatile solids) with PI dosages from 0 to 100 mg per g TS (TS, total solids). Electron spin resonance showed PI could be activated without extra activator addition, which might be attributed to the native transition metals (e.g., Fe2+) in WAS, thereby generating hydroxyl radical (•OH), superoxide radicals (•O2−), and singlet oxygen (1O2). Further scavenging tests demonstrated all of them synergistically promoted WAS disintegration, and their contributions were in the order of •O2− > •OH > 1O2, leading to the release of substantial biodegradable substances (i.e., proteins and polysaccharides) into the liquid phase for subsequent biotransformation. Moreover, fluorescence and ultraviolet spectroscopy analyses indicated the recalcitrant organics (especially lignocellulose and humus) could be degraded by reducing their aromaticity under oxidative stress of PI, thus readily for methanogenesis. Microbial community analysis revealed some microorganisms participating in hydrolysis, acidogenesis, and acetoclastic methanogenesis were enriched after PI pretreatment. The improved key enzyme activities and up-regulated metabolic pathways further provided direct evidence for enhanced methane production. This research was expected to broaden the application scope of PI and provide more diverse pretreatment choices for energy recovery through anaerobic digestion.

Periodate, a platform oxidizer, can be electrochemically recycled in a self‐cleaning process. Electrosynthesis of periodate is well established at boron‐doped diamond (BDD) anodes. However, recovered iodate and other iodo species for recycling can contain traces of organic impurities from previous applications. For the first time, it was shown that the organic impurities do not hamper the electrochemical re‐oxidation of used periodate. In a hydroxyl‐mediated environment, the organic compounds form CO2 and H2O during the degradation process. This process is often referred to as "cold combustion" and provides orthogonal conditions to periodate synthesis. To demonstrate the strategy, different dyes, pharmaceutically active ingredients, and iodine compounds were added as model contaminations into the process of electrochemical periodate production. UV/Vis spectroscopy, NMR spectroscopy, and mass spectrometry (MS) were used to monitor the degradation of organic molecules, and liquid chromatography‐MS was used to control the purity of periodate. As a representative example, dimethyl 5‐iodoisophthalate (2 mm), was degraded in 90, 95, and 99 % while generating 0.042, 0.054, and 0.082 kilo equiv. of periodate, respectively. In addition, various organic iodo compounds could be fed into the periodate generation for upcycling such iodo‐containing waste, for example, contrast media. [ABSTRACT FROM AUTHOR]

Light yellow, air‐sensitive single‐crystals of the rhodium(III) orthoperiodato K8[Rh(IO6)2]OH ⋅ 3H2O were synthesized starting from Rh2O3 and KIO4. The reaction was carried out in a potassium hydroxide hydroflux with a molar water‐base ratio of 1.8 at 200 °C. Single‐crystal X‐ray diffraction revealed a triclinic crystal structure (space group P1‾). The most striking feature of the structure is the [Rh(IO6)2]7− anion, a linear sequence of three face‐sharing octahedra. It can be interpreted as a rhodium(III) cation coordinated by two orthoperiodato groups. A water molecule and a hydroxide ion form an associate (H3O2)−. Together with other water molecules, they connect the [Rh(IO6)2]7− anions via hydrogen bridges to form layers. Upon heating, the compound first loses its crystal water, then the iodine is gradually reduced before evaporating during the final decomposition step, which results in K0.63RhO2. In K8[Rh(IO6)2]OH ⋅ 3H2O, the unusually short RhIII−IVII distance of only 276.38(1) pm should allow direct charge transfer in the [Rh(IO6)2]7− anion. An electron‐poor rhodium cation, accessible from the side, could be the active center in the rhodium‐catalyzed oxidation of unsaturated organic molecules by periodate. [ABSTRACT FROM AUTHOR]

The chemistry of low-valent intermediates continues to inspire new modes of reactivity across synthetic chemistry. But while the generation and reactivity of both carbenes and nitrenes are well-established, difficulties in accessing oxene, their oxygen-based congener, has severely hampered its application in synthesis. Here, we report a conceptually novel approach to oxene generation through the violet-light photolysis of tetrabutylammonium periodate. By revealing an unexpected geometric change upon periodate photoexcitation that facilitates intersystem crossing, we have exploited the near-barrierless dissociation of triplet periodate into oxene. Under these operationally simple conditions, we have demonstrated the epoxidation of a wide range of substituted olefins, revealing unprecedented functional group compatibility. By overcoming the historic challenges associated with employing oxene as an intermediate in organic chemistry, we believe that this platform will inspire the development of new reactive oxygen-based methodologies across industry and academia., (© 2024 Wiley‐VCH GmbH.)

The widespread occurrence of atrazine (ATZ) in water environments presents a considerable risk to human health and ecosystems. Herein, the performance of dielectric barrier discharge integrated with periodate (DBD/PI) for ATZ decomposition was evaluated. Results demonstrated that the DBD/PI system improved ATZ decomposition efficiency by 18.2-22.5% compared to the sole DBD system. After 10 min treatment, the decomposition efficiency attained 82.4% at a discharge power of 68 W, a PI dosage of 0.02 mM, and an initial ATZ concentration of 10 mg/L. As the PI dosage increased, the decomposition efficiency exhibited a trend of initially increasing, followed by a decrease. Acidic conditions were more favorable for ATZ removal compared to alkaline and neutral conditions. Electron paramagnetic resonance (EPR) was adopted for characterizing the active species produced in the DBD/PI system, and quenching experiments revealed their influence on ATZ decomposition following a sequence of 1 O 2 > O 2 - • > IO 3 • > OH•. The decomposition pathways were proposed based on the theoretical calculations and intermediate identification. Additionally, the toxic effects of ATZ and its intermediates were assessed. This study demonstrates that the DBD/PI treatment represents an effective strategy for the decomposition of ATZ in aquatic environments.

The development of effective and selective oxidation technology in complex water matrices is crucial for water ecological security. This study reports for the first time the synergistic use of "oxidant-oxidant" about sodium percarbonate (SPC) and periodate (PI) to selectively degrade organic micropollutants. The SPC/PI system showed degradation rates of 0.0946-0.2978 min -1 for various pollutants, which was 3.7-1787 times higher than those in the PI alone and SPC alone systems and can achieve the effect of H 2 O 2 /PI systems. Additionally, SPC/PI was a safe water treatment technology without generating reactive iodine species (e.g., HOI). The slightly reduced removal rate of bisphenol F under different ionic species and strengths is indicative of the good anti-interference of the SPC/PI system. Scavenging, probe, and electron spin resonance experiments showed that ▪ OH and CO 3 ▪- played a major role in this process, rather than O 2 ▪- and 1 O 2 . Finally, the oxidized products and the possible transformation pathways of three different micropollutants in the SPC/PI and H 2 O 2 /PI systems were characterized and clarified, and the toxicity of the degradation products was predicted. Generally, the study proposed a new selective oxidation strategy of SPC/PI that can effectively eliminate micropollutants in water treatment and clarified the interaction mechanisms between PI and SPC., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The utilization of periodate (PI, IO 4 - ) in metal-based advanced oxidation processes (AOPs) for the elimination of emerging contaminants (ECs) have garnered significant attention. However, the commonly used homogeneous metal catalyst Mn(II) performs inadequately in activating PI. Herein, we exploited a novel AOP technology by employing the complex of Mn(II) with the biodegradable picolinic acid (PICA) to activate PI for the degradation of electron-rich pollutants. The performance of the Mn(II)-PICA complex surpassed that of ligand-free Mn(II) and other Mn(II) complexes with common aminopolycarboxylate ligands. Through scavenger, sulfoxide-probe transformation, and 18 O isotope-labeling experiments, we confirmed that the dominant reactive oxidant generated in the Mn(II)-PICA/PI system was high-valent manganese-oxo species (Mn(V)=O). Due to its reliance on Mn(V)=O, the Mn(II)-PICA/PI process exhibited remarkable selectivity and strong anti-interference during EC oxidation in complex water matrices. Nine structurally diverse pollutants were selected for evaluation, and their lnk obs values in the Mn(II)-PICA/PI system correlated well with their electrophilic/nucleophilic indexes, E HOMO , and vertical IP (R 2 = 0.79-0.94). Additionally, IO 4 - was converted into non-toxic iodate (IO 3 - ) without producing undesired iodine species such as HOI, I 2 , and I 3 - . This study provides a novel protocol for metal-based AOPs using PI in combination with chelating agents and high-valent metal-oxo species formation during water purification., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Sensitive biomaterials subjected to surface modification require delicate methods to preserve their structures and key properties. These include collagen-sealed polyester vascular prostheses. For their functionalization, coating with polycatecholamines (PCAs) can be used. PCAs change some important biological properties of biomaterials, e.g., hydrophilicity, bioactivity, antibacterial activity, and drug binding. The coating process can be stimulated by oxidants, organic solvents, or process conditions. However, these factors may change the properties of the PCA layer and the matrix itself. In this work, collagen-sealed vascular grafts were functionalized with a poly(l-DOPA) (PLD) layer using novel seawater-inspired ion combination as an accelerator, compared to the sodium periodate, Cu 2+ /H 2 O 2 mixture, and accelerator-free reference methods. Then, poly(l-DOPA) was used as the interface for antibiotic binding. The coated prostheses were characterized (SEM, FIB-SEM, FTIR, UV/vis), and their important functional parameters (mechanical, antioxidant, hemolytic, and prothrombotic properties, bioactivity, stability in human blood and simulated body fluid (SBF), antibiotic binding, release, and antibacterial activity) were compared. It was found that although sodium periodate increased the strength and drug-binding capacity of the prosthesis, it also increased the blood hemolysis risk. Cu 2+ /H 2 O 2 destabilized the mechanical properties of the coating and the graft. The seawater-inspired ion-accelerated method was efficient, stable, and matrix- and human blood-friendly, and it stimulated hydroxyapatite formation on the prosthesis surface. The results lead to the conclusion that selection of the PCA formation accelerator should be based on a careful analysis of the biological properties of medical devices. They also suggest that the ion-accelerated method of PLD coating on medical devices may be highly effective and safer than the oxidant-accelerated coating method.