•FeP presents a superior activity for activating H2O2 to degrade organic pollutants.•The high electron transfer ability of FeP contributes to its superior activity.•The robust FeP catalyst can treat ...various pollutants and actual water samples.•Macro-sized-supported FeP catalyst pellets exhibit excellent performance.
Heterogeneous Fenton reaction has a great application potential in water purification, but efficient catalysts are still lacking. Iron phosphide (FeP) has a higher activity than the conventional Fe-based catalysts for Fenton reactions, but its ability as a Fenton catalyst to directly activate H2O2 remains unreported. Herein, we demonstrate that the fabricated FeP has a lower electron transfer resistance than the typical conventional Fe-based catalysts, i.e., Fe2O3, Fe3O4, and FeOOH, and thus could active H2O2 to produce hydroxyl radicals more efficiently. In the heterogeneous Fenton reactions for sodium benzoate degradation, the FeP catalyst presents a superior activity with a reaction rate constant more than 20 times those of the other catalysts (i.e., Fe2O3, Fe3O4, and FeOOH). Moreover, it also exhibits a great catalytic activity in the treatment of real water samples and has a good stability in the cycling tests. Furthermore, the FeP could be loaded onto a centimeter-sized porous carbon support and the prepared macro-sized catalyst exhibits an excellent water treatment performance and can be well recycled. This work reveals a great potential of FeP as a catalyst for heterogeneous Fenton reactions and may inspire further development and practical application of highly efficient catalysts for water purification.
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Clarifying the reaction pathways at the solid-water interface and in bulk water solution is of great significance for the design of heterogeneous catalysts for selective oxidation of organic ...pollutants. However, achieving this goal is daunting because of the intricate interfacial reactions at the catalyst surface. Herein, we unravel the origin of the organic oxidation reactions with metal oxide catalysts, revealing that the radical-based advanced oxidation processes (AOPs) prevail in bulk water but not on the solid catalyst surfaces. We show that such differing reaction pathways widely exist in various chemical oxidation (e.g., high-valent Mn
and MnO
) and Fenton and Fenton-like catalytic oxidation (e.g., Fe
and FeOCl catalyzing H
O
, Co
and Co
O
catalyzing persulfate) systems. Compared with the radical-based degradation and polymerization pathways of one-electron indirect AOP in homogeneous reactions, the heterogeneous catalysts provide unique surface properties to trigger surface-dependent coupling and polymerization pathways of a two-electron direct oxidative transfer process. These findings provide a fundamental understanding of catalytic organic oxidation processes at the solid-water interface, which could guide the design of heterogeneous nanocatalysts.
Recently, peroxymonosulfate (PMS)-based advanced oxidation processes have exhibited broad application prospects in the environment field. Accordingly, a simple, rapid, and ultrasensitive method is ...highly desired for the specific recognition and accurate quantification of PMS in various aqueous solutions. In this work, SO4 •–-induced aromatic hydroxylation was explored, and based on that, for the first time, a novel fluorescence method was developed for the PMS determination using Co2+ as a PMS activator and benzoic acid (BA) as a chemical probe. Through a suite of spectral, chromatographic, and mass spectrometric analyses, SO4 •– was proven to be the dominant radical species, and salicylic acid was identified as the fluorescent molecule. As a result, a whole radical chain reaction mechanism for the generation of salicylic acid in the BA/PMS/Co2+ system was proposed. This fluorescence method possessed a rapid reaction equilibrium (<1 min), an ultrahigh sensitivity (detection limit = 10 nM; quantification limit = 33 nM), an excellent specificity, and a wide detection range (0–100 μM). Moreover, it performed well in the presence of possible interfering substances, including two other peroxides (i.e., peroxydisulfate and hydrogen peroxide), some common ions, and organics. The detection results for real water samples further validated the practical utility of the developed fluorescence method. This work provides a new method for the specific recognition and sensitive determination of PMS in complex aqueous solutions.
As one of the extensively used feed additives in livestock and poultry breeding, p-arsanilic acid (p-ASA) has become an organoarsenic pollutant with great concern. For the efficient removal of p-ASA ...from water, the combination of chemical oxidation and adsorption is recognized as a promising process. Herein, hollow/porous Mn–Fe-mixed oxide (MnFeO) nanocubes were synthesized and used in coupling with peroxymonosulfate (PMS) to oxidize p-ASA and remove the total arsenic (As). Under acidic conditions, both p-ASA and total As could be completely removed in the PMS/MnFeO process and the overall performance was substantially better than that of the Mn/Fe monometallic system. More importantly, an interface-promoted direct oxidation mechanism was found in the p-ASA-involved PMS/MnFeO system. Rather than activate PMS to generate reactive oxygen species (i.e., SO4 ·–, ·OH, and 1O2), the MnFeO nanocubes first adsorbed p-ASA to form a ligand–oxide interface, which improved the oxidation of the adsorbed p-ASA by PMS and ultimately enhanced the removal of the total As. Such a direct oxidation process achieved selective oxidation of p-ASA and avoidance of severe interference from the commonly present constituents in real water samples. After facile elution with dilute alkali solution, the used MnFeO nanocubes exhibited superior recyclability in the repeated p-ASA removal experiments. Therefore, this work provides a promising approach for efficient abatement of phenylarsenical-caused water pollution based on the PMS/MnFeO oxidation process.
Abstract
A series of BiOBr
x
I
1−x
solid solutions were explored as novel visible light-sensitive photocatalysts. These BiOBr
x
I
1−x
solid-solution photocatalysts grew into two-dimensional ...nanoplates with exposed (001) facets and possessed continuously modulated band gaps from 2.87 to 1.89 eV by decreasing the Br/I ratio. The photocatalytic activities of these samples were measured and the samples exhibited visible light-driven activities for the degradation of Rhodamine B (RhB). In particular, BiOBr
0.8
I
0.2
exhibited the highest activity for the degradation of RhB. This result could be attributed to the balance between the effective light absorption and adequate redox potential. Additionally, investigations into the photocatalytic mechanism showed that the photodegradation of RhB over BiOBr
0.8
I
0.2
solid-solution photocatalysts involved direct holes oxidation, in which the reaction that dominated during photocatalysis was determined by the potential of the valence band. Furthermore, a high stability in the photocatalytic activity of BiOBr
0.8
I
0.2
was demonstrated by the cycling photocatalytic experiment and long-term irradiation, which might offer opportunities for its practical application as a catalyst.
Seedlessness is an important economic trait of lemon. Understanding the cellular and molecular mechanisms of seedlessness in ‘Xiangshui’ lemon requires detailed data on pollen and embryo sac ...fertility, embryo development and compatibility mechanisms governing self- and cross-pollination. The results of the current study indicate that the fertility of pollen and mature embryo sac remains normal. When flowers were self- or cross-pollinated, pollen grains of ‘Xiangshui’ were able to germinate on the stigma. In the case of self-pollination, pollen tubes became twisted, tube tips enlarged and tubes ruptured in the bottom of stigma. Following cross-pollination, tubes were able to grow normally in the style and ovary and enter the embryo sac, where double fertilization took place. Embryonic development resulting from cross-pollination was normal. After cross-pollination, the zygote began to divide at 2 weeks post-pollination, with early globular embryos observed after 3 weeks, globular and heart-shaped embryos at 4 weeks, torpedo-shaped embryos at 5 weeks, cotyledonary embryos at 6 weeks and thereafter germinable seeds. After self-pollination, however, ovules began to abort at 2 weeks post-pollination, with ovules disappearing at 5 weeks, ultimately producing seedless fruits. Emasculated unpollinated flowers also developed into seedless fruits, indicating that seedlessness contributes to parthenocarpy. However, gametophytic self-incompatibility has a major role in seedlessness in ‘Xiangshui’ lemon by blocking fertilization at the bottom of the stigma.
The catalytic properties of ultrafine metal nanoparticles (NPs) are usually limited by their dispersion of NPs; support is thus needed for ultrafine metal NPs. However, single-dimensional supports ...cannot exhibit a superior catalytic performance because of the ease of aggregation. In this work, we design a hierarchical structure comprising 0D ultrafine nickel (Ni) NPs, flower-like 3D MoS2 nanosheets (NSs), and 2D graphene for a superior catalytic performance. In this design, flower-like 3D MoS2 NSs were the support backbone for the growth of 0D ultrafine Ni NPs and 2D graphene was used to hamper the aggregation and deformation of MoS2 NSs. The well-dispersed hierarchical structures with great structural stability exhibited excellent catalytic activity for the catalytic hydrolysis of ammonia–borane and catalytic reduction of 4-nitrophenol by sodium borohydride in aqueous solutions. The mechanism behind the catalytic reduction was also elaborated using the in situ Fourier transform infrared spectroscopy technique. This design strategy provides a powerful approach for ultrafine metal NPs to achieve a superior catalytic performance because the composition of the hierarchical structure could be adjusted and replaced. Moreover, the designed 3D hierarchical structure could be extended to other heterogeneous catalysis systems.
•Proposed multiview error concealment method is 5.53dB better than latest method.•Optimal reference view selection for DIBR (Depth image based rendering) is proposed.•The 1-to-1 pixels are chosen, ...and the light compensation is estimated correctly.•The many-to-1 pixels are better estimated with the aid of depth information.•Hole pixels are improved efficiently with the neighboring available motion vectors.
An improved DIBR-based (Depth image based rendering) whole frame error concealment method for multiview video with depth is designed. An optimal reference view selection is first proposed. The paper further includes three modified parts for the DIBRed pixels. First, the missing 1-to-1 pixels are concealed by the pixels from another view. The light differences between views are taken care of by the information of the motion vector of the projected coordination and a reverse DIBR procedure. Second, the generation of the many-to-1 pixels is improved via their depth information. Third, the hole pixels are found using the estimated motion vectors derived efficiently from a weighted function of the neighboring available motion vectors and their distance to the target hole pixel. The experimental results show that, compared to the state-of-the-art method, the combined system of the four proposed methods is superior and improves the performance by 5.53dB at maximum.
The horticultural industry is getting more prospective with upgrading of the living standard in Guangxi Province, China. Compared to other crops, horticultural products not only are used as foods for ...human health but also contribute to healing of the people's spirit. The present status and constraints of the horticultural industry in Guangxi Province were reviewed in each of the fruit, vegetable and flower industries, in connection with favorable weather conditions and resources of the province. Strategies for developing the horticultural industry in Guangxi Province were given as follows: (1) to work out a comprehensive plan with addressing the regional specificities; (2) to strengthen the abilities of technical supporters; and (3) to enhance the investment fund to establish a production base and to set up the information exchange service system for marketing.
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