Metal ions-mediated concerted electron-proton transfer enables catalytic oxidation of phenolic contaminants by permanganate.

Permanganate has been extensively applied in water treatment due to its ease of handling and high stability. However, the impact of common water constituents, especially metal ions, on permanganate oxidation is poorly understood. Here, we report that many redox-inactive metal ions, such as Ca, Mg, Zn, Cu, and Al, can enhance the reactivity of permanganate with phenolic compounds.

Neutral Phenolic Contaminants Are Not Necessarily More Resistant to Permanganate Oxidation Than Their Dissociated Counterparts: Importance of Proton-Coupled Electron Transfer.

Despite decades of research on phenols oxidation by permanganate, there are still considerable uncertainties regarding the mechanisms accounting for the unexpected parabolic pH-dependent oxidation rate. Herein, the pH effect on phenols oxidation was reinvestigated experimentally and theoretically by highlighting the previously unappreciated proton transfer. The results revealed that the oxidation of protonated phenols occurred via proton-coupled electron transfer (PCET) pathways, which can switch from ETPT (electron transfer followed by proton transfer) to CEPT (concerted electron-proton transfer) or PTET (proton transfer followed by electron transfer) with an increase in pH.

Green polyaspartic acid as a novel permanganate activator for enhanced degradation of organic contaminants: Role of reactive Mn(III) species.

Attention has been long focused on enhancing permanganate (Mn(VII)) oxidation capacity for eliminating organic contaminants via generating active manganese intermediates (AMnIs). Nevertheless, limited consideration has been given to the unnecessary consumption of Mn(VII) due to the spontaneous disproportionation of AMnIs during their formation. In this work, we innovatively introduced green polyaspartic acid (PASP) as both reducing and chelating agents to activate Mn(VII) to enhance the oxidation capacity and utilization efficiency of Mn(VII).

Unraveling the intrinsic mechanism behind the selective oxidation of sulfonamide antibiotics in the Mn(II)/periodate process: The overlooked surface-mediated electron transfer process.

Mn(II) exhibits a superb ability in activating periodate (PI) for the efficient degradation of aqueous organic contaminants. Nevertheless, ambiguous conclusions regarding the involved reactive species contributing to the removal of organic contaminants remain unresolved. In this work, we found that the Mn(II)/PI process showed outstanding and selective reactivity for oxidizing sulfonamides with the removal ranging from 57.

Understanding the Importance of Periodate Species in the pH-Dependent Degradation of Organic Contaminants in the HO/Periodate Process.

Although periodate-based advanced oxidation processes have been proven to be efficient in abating organic contaminants, the activation properties of different periodate species remain largely unclear. Herein, by highlighting the role of HIO, we reinvestigated the pH effect on the decontamination performance of the HO/periodate process. Results revealed that elevating pH from 2.

Enhanced dewaterability of waste activated sludge by a combined use of permanganate and peroxymonosulfate.

Ever-increasing efforts have been made to develop rapid and practical conditioning methods of sludge dewatering. This study demonstrated an innovative combination of potassium permanganate (KMnO) and peroxymonosulfate (PMS) for sludge dewatering. The combined use of KMnO and PMS (KMnO/PMS) showed its superiority in improving sludge dewaterability over the separate use of KMnO or PMS.

Oxidation of Microcystin-LR via Activation of Peroxymonosulfate Using Ascorbic Acid: Kinetic Modeling and Toxicity Assessment.

Advanced oxidation processes (AOPs) have been widely used for the destruction of organic contaminants in the aqueous phase. In this study, we introduce an AOP on activated peroxymonosulfate (PMS) by using ascorbic acid (HA) to generate sulfate radicals (SO). Sulfate radicals, hydroxyl radicals (HO), and ascorbyl radicals (A) were found using electron spin resonance (ESR).

A comparative study of microcystin-LR degradation by electrogenerated oxidants at BDD and MMO anodes.

This study investigated the electrochemical degradation of microcystin-LR (MC-LR) using boron-doped diamond (BDD) anode and mixed metal oxides (MMO, IrOTaO/Ti) anode in different medium. In-situ electrogenerated oxidants including hydroxyl radical, active chlorine, and persulfate were confirmed in phosphate, chloride, and sulfate medium, respectively. Different from MMO anode, hydroxyl radical was observed to play a significant role in chlorine generation at BDD anode in chloride medium.

Facile solution synthesis of α-FeF3·3H2O nanowires and their conversion to α-Fe2O3 nanowires for photoelectrochemical application.

We report for the first time the facile solution growth of α-FeF(3)·3H(2)O nanowires (NWs) in large quantity at a low supersaturation level and their scalable conversion to porous semiconducting α-Fe(2)O(3) (hematite) NWs of high aspect ratio via a simple thermal treatment in air. The structural characterization by transmission electron microscopy shows that thin α-FeF(3)·3H(2)O NWs (typically <100 nm in diameter) are converted to single-crystal α-Fe(2)O(3) NWs with internal pores, while thick ones (typically >100 nm in diameter) become polycrystalline porous α-Fe(2)O(3) NWs. We further demonstrated the photoelectrochemical (PEC) application of the nanostructured photoelectrodes prepared from these converted hematite NWs.

Low temperature solution-phase growth of ZnSe and ZnSe/CdSe core/shell nanowires.

High quality ZnSe nanowires (NWs) and complementary ZnSe/CdSe core/shell species have been synthesized using a recently developed solution-liquid-solid (SLS) growth technique. In particular, bismuth salts as opposed to pre-synthesized Bi or Au/Bi nanoparticles have been used to grow NWs at low temperatures in solution. Resulting wires are characterized using transmission electron microscopy and possess mean ensemble diameters between 15 and 28 nm with accompanying lengths ranging from 4-10 μm.

Direct visualization of colloidal gelation under confinement.

The physical mechanism of colloidal gelation remains inadequately understood, particularly for intermediate to high volume fractions. Experiments to directly probe the complex evolution of structural and viscoelastic properties of gels have been few despite their fundamental importance in elucidating the physical mechanisms responsible for gelation. In this study, we use a home-built micron-gap rheometer combined with confocal microscopy to directly investigate the coupled structural and dynamic properties of colloidal gelation transition by spatial confinement.

Photocurrent polarization anisotropy of randomly oriented nanowire networks.

While the polarization sensitivity of single or aligned NW ensembles is well-known, this article reports on the existence of residual photocurrent polarization sensitivities in random NW networks. In these studies, CdSe and CdTe NWs were deposited onto glass substrates and contacted with Au electrodes separated by 30-110 microm gaps. SEM and AFM images of resulting devices show isotropically distributed NWs between the electrodes.

A study on relationship of nitric oxide, oxidation, peroxidation, lipoperoxidation with chronic chole-cystitis.

AIM:To study relationship of injury induced by nitric oxide, oxidation, peroxidation,lipoperoxidation with chronic cholecystitis.METHODS:The values of plasma nitric oxide (P-NO), plasma vitamin C (P-VC), plasma vitamin E (P-VE), plasma beta-carotene (P-beta-CAR), plasma lipoperoxides (P-LPO), erythrocyte superoxide dismutase (E-SOD), erythrocyte catalase (E-CAT), erythrocyte glutathione peroxidase (E-GSH-Px) activities and erythrocyte lipoperoxides (E-LPO) level in 77 patients with chronic cholecystitis and 80 healthy control subjects were determined, differences of the above average values between the patient group and the control group and differences of the average values between preoperative and postoperative patients were analyzed and compared, linear regression and correlation of the disease course with the above determination values as well as the stepwise regression and correlation of the course with the values were analyzed.RESULTS:Compared with the control group, the average values of P-NO, P-LPO, E-LPO were significantly increased (P<0.