Catalytic oxidation of Mn(II) in the co-presence of Fe(II) by free chlorine: significance of in situ formed Mn(II)-doped Fe(III) oxides.

Fe(II) and Mn(II) are abundant in groundwater and require operationally simple and efficient method to remove in drinking water treatment. The rapid oxidation of Mn(II) is essential in water treatment. This study investigates the efficiency of Mn(II) oxidation by free chlorine in the presence of Fe(II).

Novel catalyst-free activation of chlorine by visible light for micropollutant abatement.

This study systematically investigated the direct activation of chlorine by visible light emitting diode (Vis-LED). Vis-LED could effectively activate chlorine to degrade micropollutants with degradation efficiency and pseudo-first-order degradation rate constant range of 64.3-100 % and 0.

Transforming Plain LaMnO Perovskite into a Powerful Ozonation Catalyst: Elucidating the Mechanisms of Simultaneous A and B Sites Modulation for Enhanced Toluene Degradation.

Herein, we propose preferential dissolution paired with Cu-doping as an effective method for synergistically modulating the A- and B-sites of LaMnO perovskite. Through Cu-doping into the B-sites of LaMnO, specifically modifying the B-sites, the double perovskite LaCuMnO was created. Subsequently, partial La from the A-sites of LaCuMnO was etched using HNO, forming novel LaCuMnO/MnO (LCMO/MnO) catalysts.

Thermal decomposition characteristics of BHT and its peroxide (BHTOOH).

2,6-Di-tert-butyl-4-methylphenol (BHT) is an excellent antioxidant that is easily oxidized to 2,6-di-tert-butyl-4-hydroperoxyl-4-methyl-2,5-cyclohexadienone (BHTOOH). For the safety of BHT production and usage, it is meaningful to study the thermal stability and decomposition properties of BHT and BHTOOH. In this paper, the thermal decomposition properties of BHT and BHTOOH were compared by the mini closed pressure vessel test (MCPVT) and differential scanning calorimetry (DSC).

Constructed electron-dense Mn sites in nitrogen-doped MnO for efficient catalytic ozonation of pyrazines: Degradation and odor elimination.

In this study, N-doped MnO catalysts (Mn-nN) with electron-dense Mn sites were synthesized and employed in heterogeneous catalytic ozonation (HCO). These catalysts demonstrated excellent performance in pyrazines degradation and odor elimination. The synthesis of Mn-nN was achieved through a facile urea-assisted heat treatment method.

Mn(II) oxidation by the UV/chlorine system under near-neutral pH conditions: The important role of ClO and ClO.

The oxidation kinetics of Mn(II) by free chlorine is relatively low under near-neutral pH conditions which limits the Mn removal efficiency in drinking water treatment. Therefore, this study investigated the oxidation efficiency of Mn(II) by the UV-enhanced chlorination (UV/chlorine) system and identified the responsible reactive radical species. The results show that the oxidation kinetic of Mn(II) was greatly enhanced by the UV/chlorine system under near-neutral pH or even acidic conditions.

Oxidation characteristic and thermal runaway of isoprene.

In this study, the oxidation characteristics of isoprene were investigated using a custom-designed mini closed pressure vessel test (MCPVT). The results show that isoprene is unstable and polymerization occurs under a nitrogen atmosphere. Under an oxygen atmosphere, the oxidation process of isoprene was divided into three stages: (1) isoprene reacts with oxygen to produce peroxide; (2) Peroxides produce free radicals through thermal decomposition; (3) Free radicals cause complex oxidation and thermal runaway reactions.

CuAPO-5 as a Multiphase Catalyst for Synthesis of Verbenone from α-Pinene.

Copper(II)-containing aluminum phosphate material (CuAPO-5) was synthesized hydrothermally and used as a multiphase catalyst for the oxidation of α-pinene to verbenone. The catalysts were analyzed using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area techniques, X-ray photoelectron spectroscopy (XPS), and ammonia temperature programmed reduction (NH-TPD). Scanning electron microscopy (SEM), X-ray energy spectrometry (EDS), inductively coupled plasma emission spectroscopy (ICP-OES), Fourier infrared spectroscopy (FT-IR), and ultraviolet-visible spectroscopy (UV-vis) were performed to characterize the material.

Macrolactonization of methyl 15-hydroxypentadecanoate to cyclopentadecanolide using KF-La/γ-AlO catalyst.

It has been a challenge to synthesize macrolide musk in excellent yields with high purity. KF-La/γ-AlO catalyst was prepared from a highly basic mesoporous framework using a mild method. The prepared KF-La/γ-AlO catalyst was employed for the synthesis of cyclopentadecanolide from methyl 15-hydroxypentadecanoate.

Thermal stability and pathways for the oxidation of four 3-phenyl-2-propene compounds.

Cinnamaldehyde, cinnamyl alcohol, β-methylstyrene and cinnamic acid are four important biomass 3-phenyl-2-propene compounds. In the field of perfume and organic synthesis, their thermal stability and oxidation pathways deserve attention. This paper reports a new attempt to investigate the thermal stability and reactivity by a custom-designed mini closed pressure vessel test (MCPVT).

Reactivity and kinetics of 1,3-butadiene under ultraviolet irradiation at 254 nm.

The reaction process of gaseous 1,3-butadiene following ultraviolet irradiation at the temperature range from 298 to 323 K under nitrogen atmosphere was monitored by UV-vis spectrophotometry. A gaseous mini-reactor was used as a reaction vessel and could be directly monitored in a UV-vis spectrophotometer. We investigated the reactivity and kinetics of 1,3-butadiene under non-UV and UV irradiation to evaluate its photochemical stability.

UVA-LED-Assisted Activation of the Ferrate(VI) Process for Enhanced Micropollutant Degradation: Important Role of Ferrate(IV) and Ferrate(V).

This paper investigated ultraviolet A light-emitting diode (UVA-LED) irradiation to activate Fe(VI) for the degradation of micropollutants (e.g., sulfamethoxazole (SMX), enrofloxacin, and trimethoprim).

Calcium Glycerolate Catalyst Derived from Eggshell Waste for Cyclopentadecanolide Synthesis.

The synthesis costs of macrolide musks are higher than those of other commercial musks. To make this process less expensive, eggshell waste was calcined at a low temperature to obtain a catalyst for the cyclopentadecanolide production reactive distillation using a glycerol entrainer. X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses of the original and recovered catalysts revealed that the main catalytic ingredient was calcium glycerolate (CaG) and not calcium diglyceroxide (CaDG).

Kinetics of Thallium(I) Oxidation by Free Chlorine in Bromide-Containing Waters: Insights into the Reactivity with Bromine Species.

The oxidation of thallium [Tl(I)] to Tl(III) by chlorine (HOCl) is an important process changing its removal performance in water treatment. However, the role of bromide (Br), a common constituent in natural water, in the oxidation behavior of Tl(I) during chlorination remains unknown. Our results demonstrated that Br was cycled and acted as a catalyst to enhance the kinetics of Tl(I) oxidation by HOCl over the pH range of 5.

Efficient Degradation of Organoarsenic by UV/Chlorine Treatment: Kinetics, Mechanism, Enhanced Arsenic Removal, and Cytotoxicity.

Roxarsone (ROX) has been widely used as an organoarsenic additive in animal feeding operations and poses a risk to the environment. Here, we first report the efficient degradation of ROX by UV/chlorine, where the kinetics, removal of total arsenic (As), and cytotoxicity were investigated. The kinetics study presented that reactive chlorine species (RCS) and HO were the dominant species to react with ROX.

Mn effect on manganese oxides (MnO) nanoparticles aggregation in solution: Chemical adsorption and cation bridging.

Manganese oxides (MnO) and Mn usually co-exist in the natural environment, as well as in water treatments for Mn removal. Therefore, it is necessary to investigate the influence of Mn on the stability of MnO nanoparticles, as it is vital to their fate and reactivity. In this study, we used the time-resolved dynamic light scattering technique to study the influence of Mn on the initial aggregation kinetics of MnO nanoparticles.

Phytofabrication of Silver Nanoparticles Using Three Flower Extracts and Their Antibacterial Activities Against Pathogen Strain YY06 of Bacterial Wilt.

Bacterial wilt caused by the phytopathogen () is a devastating plant disease worldwide. The use of bactericides and antibiotics for controlling bacterial wilt has shown low efficiency and posed environmental risks. This study was to phytofabricate silver nanoparticles (AgNPs) mediated by canna lily flower ( L.

The aggregation kinetics of manganese oxides nanoparticles in Al(III) electrolyte solutions: Roles of distinct Al(III) species and natural organic matters.

This study explored the aggregation kinetics of manganese oxides (MnO) nanoparticles in Al(III) electrolyte solutions. This is a common process in both water treatments and the natural environment. The results show that aggregation kinetics are Al(III) species-dependent.

Thallium(I) Oxidation by Permanganate and Chlorine: Kinetics and Manganese Dioxide Catalysis.

The oxidation of the toxic heavy metal thallium(I) (Tl(I)) is an efficient way to enhance Tl removal from water and wastewater. However, few studies have focused on the kinetics of Tl(I) oxidation in water, especially at environmentally relevant pH values. Therefore, the kinetics and mechanisms of Tl(I) oxidation by the common agents KMnO and HOCl under environmentally relevant pH condition were explored in the present study.

Highly efficient removal of p-arsanilic acid with Fe(II)/peroxydisulfate under near-neutral conditions.

As a common animal feed additive, p-arsanilic acid (p-AsA) is thought to be excreted with little uptake and unchanged chemical structure, threatening the environment by potentially releasing more toxic inorganic arsenic. We herein investigated the removal of arsenic by in situ formed ferric (oxyhydr)oxides with the promotion of p-AsA degradation in Fe(II)/peroxydisulfate (PDS) system. Results showed that under acid conditions, p-AsA degraded very quickly and over 99% of p-AsA (5 μM) was degraded within 10 min at the optimal dosage of Fe(II) (100 μM) and PDS (150 μM) at pH 3, while less than 66.

Aggregation Kinetics of Manganese Oxides Formed from permanganate activated by (Bi)sulfite: Dual Role of Ca and Mn.

Aqueous aggregation kinetics of manganese oxides, the solid products formed during water treatment and subsurface remediation with permanganate, are crucial for its application. In this study, manganese oxides nanoparticles were in situ formed in a permanganate/(bi)sulfite system, which was found to have excellent oxidation ability. Aggregation kinetics of such manganese oxides (i.

Removal of Organoarsenic with Ferrate and Ferrate Resultant Nanoparticles: Oxidation and Adsorption.

Many investigations focused on the capacity of ferrate for the oxidation of organic pollutant or adsorption of hazardous species, while little attention has been paid on the effect of ferrate resultant nanoparticles for the removal of organics. Removing organics could improve microbiological stability of treated water and control the formation of disinfection byproducts in following treatment procedures. Herein, we studied ferrate oxidation of p-arsanilic acid ( p-ASA), an extensively used organoarsenic feed additive.

Highly effective oxidation of roxarsone by ferrate and simultaneous arsenic removal with in situ formed ferric nanoparticles.

Roxarsone (ROX) is used in breeding industry to prevent infection by parasites, stimulate livestock growth and improve pigmentation of livestock meat. After being released into environment, ROX could be bio-degraded with the formation of carcinogenic inorganic arsenic (As) species. Here, ferrate oxidation of ROX was reported, in which we studied total-As removal, determined reaction kinetics, identified oxidation products, and proposed a reaction mechanism.