Sodium Persulfate Research Articles

Photocatalytic degradation of tetracycline antibiotics in swine wastewater using Fe3+-loaded NaBiO3 coupled with sodium persulfate

The Fe3+-loaded NaBiO3 was prepared for photocatalytic removal of tetracycline hydrochloride (TCH) from swine wastewater. Fe3+ greatly reduced the recombination efficiency of the photoinduced electron–hole pairs of NaBiO3. Moreover, the TCH photocatalytic degradation rate constant of Fe3+-loaded NaBiO3 was two-times higher than that of Vis+NaBiO3 after 100 min of reaction. Fe-NaBiO3 combined with PS (100 mg L−1) favored TCH (10 mg L−1) degradation rate (98.8%) at neutral pH. Moreover, the oxidation system was not inhibited by the fulvic acid, and showed a good photocatalytic stability. The superoxide radicals were the main active species involved in the catalytic degradation.

A nanoplatform reshaping intracellular osmolarity and redox homeostasis against colorectal cancer.

Colorectal cancer (CRC) is the second most deadly cancer worldwide, with chemoresistance remaining a major obstacle in CRC treatment. Sodium persulfate (Na2S2O8) is a novel agent capable of producing •SO4- and Na+ for chemodynamic therapy (CDT). This can induce pyroptosis and ferroptosis instead of conventional apoptosis in tumor cells. Meanwhile, IR780-iodide (IR780), as an excellent phototherapy agent, can generate hyperthermia and generate a large amount of reactive oxygen species (ROS) to synergize with the CDT of Na2S2O8, with potential to overcome chemoresistance in CRC. However, the low stability of Na2S2O8 and the poor solubility of IR780 limit their applications in the medical field. Accordingly, for the first time, D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS), Na2S2O8 and IR780 were rationally designed in a cascade-amplifying nanoplatform (Na2S2O8-IR780 NPs) via a co-assembly strategy. Combining Na2S2O8 and IR780 in a nanoplatform improves the stability of Na2S2O8 and the solubility of IR780. As a result, the Na2S2O8-IR780 NPs exhibited excellent antitumor efficacy in CRC cell lines and five chemo-resistant cell lines and showed potent inhibitory capability in nude mice xenograft models. This photo-chemodynamic nanoplatform provides a brand-new paradigm by manipulating osmolarity and redox homeostasis to overcome chemo-resistance and holds great potential for the treatment of CRC.

Decontamination efficacy of common liquid disinfectants against non-spore-forming biological agents in soil matrices.

The purpose of this study was to evaluate decontamination efficacy, within three soil types, against Yersinia pestis, Burkholderia pseudomallei, and the Venezuelan Equine Encephalitis virus (VEEV). One of three liquid disinfectants (dilute bleach, Virkon-S or Klozur One) was added to three soil types (sand, loam, or clay) and allowed contact for four pre-spike durations: 0, 15, 30 and 60 min. Y. pestis, B. pseudomallei, or VEEV was then spiked into the soil (10 microliters or approx. 1 × 107 CFU or PFU into 1g soil) and decontamination efficacy assessed at post-spike contact times of 10 or 60 min at ambient environmental conditions. Across all soil types, sandy soil resulted in the least quenching to all three disinfectants tested as shown by sustained decontamination efficacy across all pre-spike and post-spike timepoints. Clay and loam soil types exhibited quenching effects on the hypochlorite and peroxygen based disinfectants (dilute bleach and Virkon S) and in general resulted in decreased efficacy with increased pre-spike contact time. The sodium persulfate (Klozur One) performance was the most consistent across all soil types and pre-spike contact times, resulting in greater efficacy with increased post-spike time. Liquid disinfectants can provide high levels of decontamination in soil for both viral and non-spore-forming bacterial select agents. Hypochlorite and peroxygen based disinfectants used in soils containing higher organic content (loam or clay) may require extended contact times or re-application of liquid disinfectant, in as little as 15 min of application, to achieve a 6-log reduction. These results provide information for the performance of three disinfectants in soil against non-spore-forming select agents. These data may aid response decision makers following a biological contamination incident by informing the selection of disinfectant as well as the re-application time to achieve effective site remediation.

Coupling iron-carbon micro-electrolysis with persulfate advanced oxidation for hydraulic fracturing return fluid treatment

Improving the sustainability of the hydraulic fracturing water cycle of unconventional oil and gas development needs an advanced water treatment that can efferently treat flowback and produced water (FPW). In this study, we developed a robust two-stage process that combines flocculation, and iron-carbon micro-electrolysis plus sodium persulfate (ICEPS) advanced oxidation to treat field-based FPW from the Sulige tight gas field, China. Influencing factors and optimal conditions of the flocculation-ICEPS process were investigated. The flocculation-ICEPS system at optimal conditions sufficiently removed the total organic contents (95.71%), suspended solids (92.4%), and chroma (97.5%), but the reaction stoichiometric efficiency (RSE) value was generally less than 5%. The particles and chroma were effectively removed by flocculation, and the organic contents was mainly removed by the ICEPS system. Fourier-transform infrared spectroscopy (FTIR) analysis was performed to track the changes in FPW chemical compositions through the oxidation of the ICEPS process. Multiple analyses demonstrated that PS was involved in the activation of Fe oxides and hydroxides accreted on the surface of the ICE system for FPW treatment, which led to increasing organics removal rate of the ICEPS system compared to the conventional ICE system. Our study suggests that the flocculation-ICEPS system is a promising FPW treatment process, which provides technical and mechanistic foundations for further field application.

Removal of antibiotic cefixime from wastewater using UVC/Sodium persulphate system

Antibiotics are reported to become a problem to the environment. Various treatment technologies have been reported in literature for antibiotics removal from water and wastewater such as physical, biological and chemical treatment techniques. Advanced oxidation processes (AOPs) having fast reaction rate and strong oxidation capability, also have been received increasing attention for removal of antibiotics. The extensive use of cefixime antibiotic has been simultaneously detected in the environmental systems. The sulfate radical based AOPs are reported to be very effective in elimination of cefixime from wastewater matrix. In the present study oxidant sodium persulphate (SPS) is applied under UVC-16 W, irradiation to remove cefixime from an aqueous solution. The influence of various parameters like cefixime initial concentration (5–30 ppm), SPS dosage (200–1000 ppm), pH (3–11), Temperature (40–70 °C), time (0–120 min) and effect presence of water matrix compounds like sodium bicarbonate, NaCl and humic substances (humic acid) was studied on the percentage removal of cefixime by UVC/SPS system.

Degradation of carbamazepine from wastewater by ultrasound-enhanced zero-valent iron -activated persulfate system (US/Fe0/PS): kinetics, intermediates and pathways

ABSTRACT Carbamazepine (CBZ) is a common antiepileptic drug. CBZ enters the environment through unreasonable and standardized ways such as human and animal metabolites, discarded drugs, and more than half of its metabolites are released into the environment. Since CBZ is not easy to be degraded, continuous input of CBZ into the water environment will cause long-term impact on the water ecological environment and seriously endanger human health. Aiming at how to degrade wastewater containing carbamazepine, studies were conducted on the degradation of carbamazepine by ultrasound/zero-valent iron/persulfate system (US/ F e 0 /PS). Firstly, the removal effects of carbamazepine by different systems, such as ultrasound/sodium persulfate (US/PS), zero-valent iron/persulfate system ( F e 0 /PS) and US/ F e 0 /PS, were compared; Secondly, the influence of factors, such as ultrasonic power, sodium persulfate dosage, zero-valent iron dosage, reaction temperature, pH, etc., on the reaction was investigated by the control variables method. Results show that ultrasound power, PS concentration, pH and temperature have a great influence on the removal of carbamazepine in US/Fe0/PS reaction system. Besides, the optimum parameters for degradation of carbamazepine with US/ F e 0 /PS reaction system were determined ([CBZ]0 = 0.025 mM; [PS]0 = 0.4 mM; Fe0 = 4.0 mg/L; ultrasonic power = 40 W; T = 30 ℃; initial pH = 5.0). Finally, the intermediates and degradation pathways of carbamazepine by US/ F e 0 /PS system were analyzed and speculated. It was inferred that two intermediates were generated during the degradation of carbamazepine, mainly through the ring opening and decyclization of piperazine rings. It was proved that process US/ F e 0 /PS has a very important application value in the degradation of antibiotic-containing wastewater.

Mechanism of thermally activated sodium persulfate–biochar skeleton treatment to improve the dewaterability of waste activated sludge

Sludge dewatering is a necessary process in the disposal of waste activated sludge (WAS). In this study, thermally activated sodium persulfate–biochar skeleton pretreatment was performed to improve the dewaterability of sludge, and its internal mechanism was systematically elucidated. The experimental results showed that, under optimal operating conditions, the water content of WAS could be reduced from 89.7% to 61.3% of the raw sludge. Under these conditions, the capillary suction time and specific resistance to filtration were roughly 23.23% and 59.57% of those in the raw sludge, respectively. This study proposes a relationship between organic matter migration and sludge physical structure that explains the dewaterability improvement mechanism. Separate thermal treatment caused organic matter such as proteins, polysaccharides, and humic substances to dissolve, releasing their bound water. Simultaneously, changes in the surface structure (pore size reductions and BET surface area increases) deteriorated the dewaterability of WAS. The reactive oxygen species generated by the thermally activated sodium persulfate further mineralized the organic matter, simplifying the floc surface structure (pore size increases and BET surface area decreases) and finally improving the dewaterability. Under these conditions, the addition of biochar increased the pore size, and further improved sludge dewaterability.

Toward green nano adsorbents and catalysts: Highly active Fe/Mn nanoparticles for enhanced oxidation of oxytetracycline and levofloxacin

The widespread use of antibiotics, such as oxytetracycline (OTC) and levofloxacin (LEV), has led to dangerous levels of environmental contamination. In this study, functionalized iron/manganese nanoparticles (Fe/Mn NPs), which act as both adsorbent and Fenton catalyst, were green-synthesized using a reducing agent derived from a tea extract. The resulting pre-sorption/Fenton-like oxidation system effectively removed both OTC and LEV from the aqueous solution with adsorption capacities of Fe/Mn NPs for OTC and LEV of 58.8 and 192.3 mg·g−1, respectively. In addition, Fe/Mn NPs also showed high catalytic activity, oxidizing more than 99.9 % of both OTC and LEV, while sodium persulfate (PDS) removed only 26.6 and 29.0 % of OTC and LEV, respectively. Mechanisms of PDS activation typically involve either catalyst-initiated or mediated electron transfer reactions. Fe/Mn NPs through heterogeneous catalytic and metal leaching-induced homogeneous Fenton reactions, which generated various reactive oxygen species (ROS) including 1O2, ·OH, SO4-· and ·O2–. Characterization of Fe/Mn NPs before and after reaction, and the identification of specific OTC and LEV degradation products by LC-MS, helped to elucidate a potential degradation pathway, as well as the removal mechanism. Finally, the practicality of using this system for wastewater treatment was demonstrated using real wastewater samples indicating that the system has great potential for simultaneously degrading both OTC and LEV in contaminated wastewater.

Bleaching powders, bleaching creams and other hair lightening preparations as sources for (airborne) allergic contact dermatitis and other health effects in hairdressers: Results of an empirical study.

Various products are available for lightening hair. There are no data on which applications are actually used in hairdressing, impeding proper estimation of actual exposure and necessary preventive measures. To assess information about availability, usage and formulation of lightening preparations in the German hairdressing trade. A market survey was conducted and hairdressers were surveyed by online questionnaires. Of 783 hairdressers clicking the link, 565 hairdressers (91.2% female, mean age of 40.2 ± 11.7 years) from all German states responded (response rate: 72.2%). The questionnaire survey has shown that available hair-lightening preparations in the German hairdressing trade are (multiple selection possible): dust-free (88.5%) and non-dust-free bleaching powders (22.1%), bleaching creams (41.9%), high-lifting hair colour creams (88.8%) and normal hair colour creams (58.4%). Five hundred eighteen (91.7%) hairdressers favour lightening hair with powder. The market survey revealed that bleaching powders and creams contain potassium persulfate, ammonium persulfate and sodium persulfate or combinations of these persulfate salts. Hairdressers are exposed to various hair-lightening applications containing different chemicals. Preventive measures need to address adverse skin and respiratory effects. Implementation of targeted health education already in early career stages (i.e., apprenticeship) seems advisable and can be maintained by refresher trainings.

Synergistic detoxification by combined reagents and safe filling utilization of cyanide tailings

Cyanide tailings are the major hazardous wastes generated in the production process of the gold industry, which not only contain highly toxic cyanide, but also contain heavy metals with recycling value and other substances suitable for building materials or filling. These tailings are in urgent need of purification treatment and safe utilization. In this study, the impacts of treatment methods, types and combinations of reagents on decyanation effect were researched. Gold in cyanide tailings was recovered by flotation, and flotation tailings were used for filling after identifying the properties of solid waste. Results are as follows: (1) INCO method and 5 reagents (sodium sulfite, sodium persulfate, copper sulfate, ferrous sulfate and zinc sulfate) were selected for synergistic decyanation treatment, and cyanide concents in slurry and leaching solution were decreased to the minimum. (2) The gold recovery rate of the tailings through flotation was increased by 27.8% than without detoxification. (3) Flotation tailings were identified as general industrial solid wastes by leaching toxicity and toxic substance content analysis. (4) As filling aggregate, under the conditions of slurry concentration of 63% and cement-sand ratio of 1:6, the strength filling body of flotation tailings reached 1.32 Mpa after 28 days of maintenance. (5) This process and combined reagents were applied to engineering. The cyanide content in the leaching solution and the flotation recovery rate of gold were kept below 0.2 mg/L and above 60% respectively, and the strength of the filling body was stable to meet the requirements of underground filling.

Kinetics, mechanism, and application of sodium persulfate activated by sodium hydroxide for removing 1,2-dichloroethane from groundwater

1,2-Dichloroethane (1,2-DCA) is a common compound found in groundwater contaminated with organics. This compound is difficult to remove from groundwater and has the potential to inflict significant harm on human health and the environment. This study used sodium persulfate (Na2S2O8) activated by sodium hydroxide (NaOH) to remove 1,2-DCA from aqueous solutions. Density functional theory was employed to calculate the potential energy surface of the reactants, intermediates, transient states, and products to thoroughly analyze the degradation pathways. The computations were performed in combination with in situ remediation of a 1,2-DCA plume from a point source to verify the industrial applicability of the technology. The results showed the 1,2-DCA removal efficiency was impacted considerably by the Na2S2O8 dosage and the dosing sequence of Na2S2O8 and NaOH, with the mean removal ratio reaching 96.24%. A free radical reaction was the main pathway of 1,2-DCA degradation; superoxide radical (O2•–) existed stably and played a key role in the reaction, and the main transformation proceeded via a vinyl chloride intermediate. The maximum removal of 1,2-DCA reached 91.79% in the in situ remediation. The developed technology exhibits important advantages in enabling flexible control over chemical dosages, long durations of effective activity, and rapid full-cycle remediation.

Структурно-морфологические свойства вторичного волокна из влагопрочного сырья при мягком размоле. Часть 1. Характеристика волокон

The efficient use of papermaking potential of secondary fiber by gentle refining of recycled pulp is one of the basic principles for the recovered paper stock preparation. The use of mild refining modes for recycled fiber is more important in the case of wetstrength paper than for conventional waste paper. This is due to the fact that recycled fiber is weakened by hard conditions of wet-strength paper repulping, in particular, long repulping time, elevated temperature, the use of alkali and oxidizers. The study aims at evaluating the changes in the morphological characteristics of secondary fiber during gentle low-consistency refining of recycled pulp. The analysis of the secondary fiber morphological characteristics was carried out in two complementary directions, i.e. the analysis of the fibers (part 1) and the analysis of the fines (part 2). Recycled pulp (RP) was obtained from commercial wetstrength tissue paper consisting of 100 % bleached softwood kraft pulp (BSKP) made of pine (Pίnus sylvéstris L.). The wet-strength paper repulping was performed at 60 °C in three ways, namely, repulping with sodium hydroxide (indicated as RP(NaOH)), repulping with sodium hydroxide and sodium persulfate (RP(NaOH + Na2S2O8)), and finally repulping with sodium hydroxide and potassium monopersulfate (RP(NaOH + KHSO5)). Secondary fibers as well as primary fibers of BSKP had similar length distribution before and after gentle refining. Mean fiber length after first recycle reduced by 5–6 %. The calculated values of the fibershortening index showed that fiber cutting practically does not occur during gentle refiningof the recycled pulps. The increase in the refining degree of the pulps is mainly explained by the fibrillation of secondary fibers, rather than the formation of a large amount of fines. Secondary fibers obtained from the wet-strength paper have a high slenderness ratio ((L/W)l from 66.3 to 66.5 and (L/W)w from 83.6 to 84.3; where L – length, W – width) corresponding to pulp with good papermaking potential. The results showed that low-consistency gentle refining of the recycled pulp obtained by accelerated persulfate and monopersulfate repulping of the wet-strength paper leads to fiber straightening. The overall increase in the shape factor of secondary fibers was achieved due to a combination of accelerated repulping of the wetstrength waste paper (by ~ 60 %) and gentle refining of the pulp (by ~ 40 %).

Fabrication of Superhydrophobic Copper via Chemical Etching and Modification

Biological superhydrophobic surfaces are relatively common in nature. Inspired by the superhydrophobic feature, plentiful materials with hydrophobic surfaces have been fabricated for various purposes such as anti-corrosion, anti-icing, self-cleaning, friction reduction, and oil-water separation. In the present work, we report a scalable, simple, and rapid method to fabricate superhydrophobic film on copper substrates via a simple route including a chemical etching step in sodium persulfate and sodium hydroxide solution and followed by a modification step in stearic acid solution. The effect of the etchants concentration as well as etching time was investigated exhaustively. From the obtained results it was found that when a copper plate was etched in an etching solution with low etchant concentration, the contact angle of copper was greatly influenced by etching time. In contrast, the etching time hardly affected the contact angle of the copper plate at the high concentration of the etchants. The superhydrophobic feature of the copper surface (with a contact angle larger than 150o) was only achieved in certain fabrication conditions. The superhydrophobic copper substrates demonstrated good anti-corrosion properties. The corrosion current density of superhydrophobic copper substrates was 85 times smaller than that of pristine ones when manufactured under optimal conditions. In addition, the as-prepared superhydrophobic copper mesh was used to successfully separate toluene from its aqueous mixture. The superhydrophobic copper has great potential for applications in oil-water separation and anti-corrosion in aqueous environments.

The fate of extracellular proteins and polysaccharides of waste activated sludge oxidative in aqueous and granular sludge phase upon degradation using Fe(II)-persulfate conditioning

Dissolved organic matter, particularly proteins (PN) and polysaccharides (PS) in extracellular polymeric substances (EPS), are regarded as the key factors influencing the dewaterability of waste activated sludge (WAS). An investigation was conducted on the treatment of WAS by Fe(II) activated sodium persulfate (SPS) to evaluate the kinetics of oxidative degradation of EPS in the aqueous and granular sludge phase, and to quantify the oxidation of SPS in aqueous and granular sludge phase in Fe(II)-SPS system. The WAS was divided into granular sludge (GS) and raw sludge filtrate (RSF) by filtration and elutriation. The PN and PS components underwent rapid degradation on treatment with Fe(II)-SPS, which followed pseudo-first-order kinetics for both GS and RSF. EPS protein was preferentially oxidatively degraded over EPS polysaccharide in the same phase system. However, the degradation rates of PN and PS in GS were 1/6 and 16 times higher than those in RSF, respectively. 23% of the sodium persulfate was consumed by all the substances in the bulk solution where the GS was located, reducing the amount of “effective free radicals” that degrade EPS in the system. The mass balance of PN and PS indicated that the use of Fe(II)-SPS conditioning has an obvious degradative effect on EPS, and PN and PS in WAS were oxidized by 76.2% and 58.3%, respectively. These findings provide mechanistic insight into the oxidation and competitive reactions of PN and PS between sludge aqueous and granular sludge phases, which is beneficial to the selection and optimization of sludge conditioning.

Numerical simulation study of oil–water separation based on a super-hydrophilic copper net

Green and environmentally friendly oil–water separation is an important technique for reducing environmental pollution. In this study, the oil–water separation effect of the super-hydrophilic copper net was optimized through numerical simulation and orthogonal experiments. To be specific, a super-hydrophilic copper net was prepared using the solution etching method to perform oil–water separation experiments, and a favorable oil–water separation effect was achieved. First, the influences of oil–water flow velocity, copper net mesh size, and surface wettability on the oil–water separation effect of the super-hydrophilic copper net were explored via single-factor experiments. The results showed that the oil resistance of the super-hydrophilic copper net degraded, and its oil–water separation effect became poor due to the increasing oil–water flow velocity, enlarged copper net mesh size, and reduced oil contact angle on the surface of the super-hydrophilic copper net. On this basis, the optimized oil–water separation parameters were obtained through orthogonal experiments. The optimized process parameters were as follows: velocity = 0.1 m/s, copper net mesh size = 30 μm, oil contact angle = 150°, and oil removal rate = 95.7%. Furthermore, the copper net was etched using sodium hydroxide and sodium persulfate mixed solution to prepare a 500-mesh super-hydrophilic copper net for the oil–water separation experiment and then the oil removal rate reached 96.4%. The study results provide a theoretical basis, method, and means for the practical application of super-hydrophilic copper nets.

Natural Polymer-Based Iron Oxide (Fe3O4) Synthesis, Characterization and Its Application for 1-Amino-Nitrobenzene Degradation in Assistance with Oxidants

A natural polymer-based iron oxide (Fe3O4) nanocomposite was prepared through a sonochemical-assisted precipitation method. Characterization studies such as X-ray diffractometer, scanning electron microscopy, and transmission electron microscopy have revealed that the synthesized nanocomposites are homogenously distributed, having an average size of ~49 nm with a cubical spinel structure. The toxic 1-amino-nitrobenzene was initially treated with a sonophotochemical process in the presence of synthesized nanocomposites, resulting in lower efficiency, whereas with the addition of oxidants, the efficiency enhanced significantly. The parametric effects with respect to the initial solution pH, nanocomposites dose, 1-amino-nitrobenzene concentration, and oxidant concentration were studied, and it was found that an approximately 75% removal efficiency of 1-amino-nitrobenzene was achieved within 120 min. Further, the performance of the catalyst on the oxidation of 1-amino-nitrobenzene with sodium persulfate was also investigated, and it was found that a 95% removal efficiency was attained.

Sodium Persulfate Pre-treatment of Copper Foils Enabling Homogenous Growth of Cu(OH)2 Nanoneedle Films for Electrochemical CO2 Reduction.

Oxide‐derived copper (OD−Cu) catalysts have received widespread attention for their ability to produce energy‐dense multicarbon products. Within this class of materials, nanostructured copper hydroxide (Cu(OH)2) has shown excellent catalytic properties, but its synthesis requires complex pre‐treatment steps of the Cu surface. In this study, we have developed a simple two‐step synthesis method for homogenous Cu(OH)2 nanoneedle films using a sodium persulfate pre‐treatment step prior to anodization. The Cu(OH)2 nanoneedle films show drastically enhanced uniformity after the pre‐treatment due to improved current distribution and can be grown over large surface areas (63 cm2). As a catalyst for CO2 reduction, the Cu(OH)2 favours ethylene formation, with a near total suppression of methane production. A peak faradaic efficiency (FE) of 36.5 % is found at −1.0 V vs. the reversible hydrogen electrode (RHE), and the catalyst remains stable while providing an ethylene to methane ratio of 27.8 after 6 h of reaction.

Enhancement of rapid hydrolysis and humification of food waste slurry by synergistically incorporating forward UV365 and persulfate

This study investigates the use of UV365 irradiation to activate sodium persulfate (PS, 1–8%) for rapid hydrolyzation and humification of food waste (FW) slurry. Physicochemical characterizations show that the hydrolysis yield reaches a maximum value (745.06 g SCOD/kg TVSadded) following UV365/4% PS application for 120 hr. Fluorescence excitation–emission matrix spectroscopy combined with parallel factor analysis indicates that FW fluorescent molecules decompose into humus-like and tryptophan-like substances, with high PS dosages (4–8%) promoting the formation of the former, as confirmed by scanning electron microscopy, gel permeation chromatography, and Fourier transform infrared spectroscopy. Our proposed mechanism involves nonselective attack by SO4•− on various FW components, leading to rapid (<12 hr) hydrolysis of the FW macromolecules to soluble small molecules (e.g., glucose, amino acids). The SO4•− radicals are then gradually consumed, and the weakly oxidizing environment catalyzes the recombination of the hydrolyzed small molecules to form humus-like substances. Our proposed method could provide valuable new insights for FW management.

Amended Safety Assessment of Persulfates as Used in Cosmetics.

The Expert Panel for Cosmetic Ingredient Safety (Panel) reassessed the safety of 3 persulfate ingredients, which function as oxidizing agents in cosmetic products. The Panel reviewed relevant data relating to the safety of these ingredients and concluded that Ammonium, Potassium, and Sodium Persulfate are safe as used as oxidizing agents in hair colorants and hair lighteners designed for brief discontinuous use followed by thorough rinsing from the hair and skin. The Panel also concluded that the available data are insufficient for determining the safety of these persulfates in leave-on products and dentifrices.

A novel ion-imprinted polymer based on pyrrole as functional monomer for the voltammetric determination of Hg(II) in water samples

A novel selective ion-imprinted polymer (IIP) was synthesized, characterized, and used as part of a carbon paste electrode (CPE) for the electrochemical analysis of Hg(II) in real water samples by differential pulse anodic stripping voltammetric (DPASV). Hg-IIP (mercury-ion imprinted polymer) was synthesized using pyrrole for the first time as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker agent, and sodium persulfate as initiator. The CPE was modified with IIP (CPE-IIP) with a composite mixture of Hg-IIP (10%), graphite (90%), and 0.08 g of paraffin oil. A notable difference in the Hg(II) Iap (anodic peak current) between a CPE, CPE-IIP and CPE-NIP (non-imprinted polymer) was observed when optimizing the differential pulse anodic stripping voltammetry (DPASV) parameters by a Box-Behnken design. When analyzing a 50 µmol l−1 Hg(II) solution, the optimal conditions (step potential: 0.11 V, amplitude: 0.15 s, modulation time: 0.005 s, and interval time: 0.15 s) allowed an Iap of 144 µA with a %RSD < 10% for the CPE-IIP response, in comparison to the Iap of 1.47 µA obtained with the CPE-NIP, Iap confirming the existence and performance of the recognition cavities in the IIP. The proposed methodology presents a limit of detection (LOD) of 0.02 mg l−1 within a linear range of 0.09 mg l−1 to 20.05 mg l−1. The inter-day and intra-day precision were measured in two concentration levels (1 mg l−1 and 10 mg l−1) with %RSD < 10%. The developed methodology was successfully applied to determine Hg(II) in three spiked samples (10 mg l−1) of natural water sources without acid digestion, obtaining percentage recoveries close to 99.74%, which demonstrates that digestion treatment is not required for this kind of samples.