Search

[Display omitted] • Fundamental knowledge on SSPFR are detailed illustrated. • Catalytic mechanism of each step and development of SSPFR are reviewed. • Various strategies aimed at improving the reaction rate are discussed and summarized. • Applications are introduced. • Prospects for the future development of SSPFR are presented. Fenton reaction has gained tremendous attention in the field of non-selective pollutant degradation, as •OH with powerful oxidizing capacity can be produced via H 2 O 2 activation. However, the widespread application is limited by the continuous consumption of commercial H 2 O 2 with high price. As an alternative strategy, self-sufficient photo-Fenton reaction (SSPFR) has been explored, where oxidant H 2 O 2 was in-situ produced inside the system for subsequent Fenton reactions, rather than external addition. Benefiting from the low cost, high H 2 O 2 utilization efficiency, and low risk in H 2 O 2 storage and transportation, SSPFR became a hotpot in scientific research, and developed rapidly in recent years. Herein, we critically reviewed the state-of-the-art development of SSPFR, in which the fundamental mechanism and catalytic process were firstly introduced. Then, SSPFR reaction was divided into three cascade steps: in-situ H 2 O 2 production, H 2 O 2 activation, and reactive oxygen species utilization. This paper reviewed the research progress in every step, and proposes corresponding potential strategies to accelerate the reaction rate. Finally, conclusions and prospects of SSPFR for the removal of organic pollutants were proposed. This study provides a valuable resource for researchers to construct novel and efficient SSPFR systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new La-MOF (1), has been successfully synthesized by employing H 4 L. • 1 has good chemical stability and thermostability. • 1 can detect TNP and Fe3+ with high selectivity and sensitivity in water. • 1 shows the great anti-interference ability and repeatability. A new Lanthanum-based luminescent metal–organic framework, {[La(H 2 O) 4 (HL)]·H 2 O} (1), has been successfully synthesized by employing 3,3′,5,5′-azodioxybenzenetetracarboxylic acid (H 4 L) as a rigid organic linker through the solvothermal reactions. 1 exhibits a two-dimensional (2D) layered structure and a three-dimensional (3D) supramolecular structure is formed by hydrogen bonds between the layers. Stability studies indicate that 1 has good chemical stability and thermostability. Meanwhile, the K sv values for TNP is 4.61 × 104 M−1 with the LOD of 4.13 × 10-6 M and the K sv value for Fe3+ is 1.22 × 104 M−1 with the LOD of 1.72 × 10-5 M, respectively, which demonstrated that 1 exhibits high sensitivity and excellent selectivity for the detection of TNP and Fe3+ via fluorescence quenching. Significantly, 1 shows high regenerability after five recycling progress for sensing Fe3+. The possible mechanisms associated with the luminescent quenching are discussed in detail through some relevant experiments and tests, as well as the DFT calculations. Based on the above excellent properties of 1 , it will have extremely potential to be used as a dual functional sensor for both detecting TNP and Fe3+ in aqueous solution, simultaneously. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ecological sources were identified using morphological spatial pattern analysis. • Resistance surface was developed from ecosystem service value. • Ecological corridors were identified using minimum cumulative resistance model. • The ecological network was optimized by similarity search. Ecological infrastructure is a popular framework for conservation planning. In this paper, one of the most urbanized regions of China-Shenzhen was chosen as the study area. Ecological infrastructure with different configurations and functions were identified and combined to form the urban ecological network. The ecological sources were identified using morphological spatial pattern analysis (MSPA) and landscape connectivity analysis. The ecological resistance surface developed from ecosystem service value was modified basing on ecological sensitivity and landscape connectivity. The ecological network was constructed by minimum cumulative resistance (MCR) model and then optimized and accessed. The results show that: (1) the ecological network consists of 25 ecological sources distributed mainly in the southeast and west. Twenty-nine ecological corridors were extracted and 36 ecological nodes identified. (2) In the optimized ecological network, 10 new ecological sources were added, and 46 ecological corridors and 59 ecological nodes were identified. It would promote the connectivity of the ecological sources and the stability of ecological functioning process. (3) The ecological network took ecosystem service value and ecological sensitivity into consideration and lays emphasis on improving landscape connectivity, providing an approach to optimizing urban ecological network and contributing to urban planning. [ABSTRACT FROM AUTHOR]

Sufficient generation of H 2 O 2 played an essential role in boosting self-sufficient heterogeneous Fenton reaction. Herein, the dual H 2 O 2 production paths were designed to maximize the yield over H 2 O 2 -etched MoS 2 /FeS 2 Z-scheme heterojunction, whose surface was modified with abundant –OH groups and sulfur vacancies (SVs). Mechanism studies revealed that H 2 O 2 was generated via two-step single-electron reduction by electrons on conduction band, where H 2 O 2 production was significantly improved by the internal hole-scavenging effect from –OH groups. Additionally, electrons surrounding SVs served as another sites for H 2 O 2 production via one-step two-electron reduction even in darkness. H 2 O 2 yield in neutral aqueous solution reached 1.5 mM/g/h without external hole scavenger. Tetracycline and rhodamine B were effectively degraded under light or in darkness. The degradation performance was even comparable to the heterogeneous Fenton reaction. This work provides new insights for the design of self-sufficient heterogeneous Fenton system with exceptional degradation performance. [Display omitted] • E-MoS 2 /FeS 2 with abundant -OH groups and SVs is prepared via surface engineering. • H 2 O 2 yield is largely improved by the internal h+-scavenging effect from –OH groups. • e - surrounding SVs serve as another sites for H 2 O 2 production even in darkness. • In-situ H 2 O 2 yield reaches 1.5 mM/g/h, and it is enough for following Fenton reaction. • Pollutant can be degraded within 25 or 60 min under actual sunlight or in darkness. [ABSTRACT FROM AUTHOR]

In peroxymonosulfate (PMS)-based Fenton-like reaction, there were two pathways for PMS activation: radical path on transition metal surface and non-radical path on heteroatom-doped carbon surface. In this work, CoS 2 /nitrogen-atom doped carbon (NC)@SiO 2 yolk@shell nanoreactor was designed, on CoS 2 /NC surface, these two paths performed parallelly inside the nanoreactor, leading to an accelerated tetracycline degradation rate. 90.9% of removal efficiency was realized within 15 min, much higher than the reference samples, and the advantages of yolk@shell nanoreactor were illustrated in detail. Moreover, benefiting from the SiO 2 shell protection, the leached cobalt ion was only 0.27 mg/L, which was 1/20 of the reference CoS 2 /NC without SiO 2 shell. During the mechanism study, the two activation paths were identified by electron paramagnetic resonance tests, radical trapping experiments and electrochemical tests, where the SO 4 •- and 1O 2 were responsible for tetracycline (TC) degradation. This study provided a new strategy to simultaneously accelerate radical activation path and non-radical activation path by using the yolk@shell nanoreactor, and it might inspire other high efficient catalyst design for PMS-based Fenton-like reaction. [Display omitted] CoS 2 /NC@SiO 2 yolk@shell nanoreactor with CoS 2 /NC nanoparticles encapsulated inside the SiO 2 shell was prepared as a catalyst in Fenton reaction. • Radical and non-radical PMS activation paths are confined in CoS 2 /NC@SiO 2 nanoreactor. • Removal rate of CoS 2 /NC@SiO 2 is 3.6×10−2 L·min·mg−1, better than reference samples. • Co3+/2+ leaching is lowered to 0.27 mg/L due to the SiO 2 shell protection. • SO 4 •- and 1O 2 are responsible for TC degradation, and catalytic mechanism are studied. • Nanoreactor shows good versatility, recyclability, and anti-interference ability. [ABSTRACT FROM AUTHOR]

Yolk@shell nanoreactor with coordinately unsaturated metal sites on Prussian blue analogue nanocubes surface inside the polypyrrole capsule was prepared, in which improving catalytic activity and lowering metal leaching were simultaneously realized. [Display omitted] • Improving activity and lowering leaching are simultaneously realized in nanoreactor. • Nanoreactor show high PMS utilization efficiency and TC mineralization efficiency. • PMS activation is encouraged via Lewis acid-base reaction on CUMSs. • SO 4 − converts to OH and then to 1O 2 inside nanoreactor under confinement effect. • Metal leaching is suppressed under the protection of compacted PPy shell. In peroxymonosulfate (PMS)-based Fenton-like reaction, there was an irreconcilable contradiction between improving the catalytic activity and lowering the metal leaching, since the more catalytic sites exposed, the better activity and the easier leaching. In this work, we have provided a feasible method to address this problem by preparing yolk@shell structure with coordinately unsaturated metal sites on Prussian blue analogue (CUMSs-PBA) nanocubes surface inside the polypyrrole (PPy) capsule. On CUMSs-PBA surface, a large amount of metal sites were exposed and functioned as Lewis acid. As Lewis base, PMS adsorption and activation were encouraged via Lewis acid-base reaction, leading to an enhanced activation efficiency. PMS and pollutants were confined inside the yolk@shell nanoreactor with a limited cavity space, leading to an ultra-high concentration and accelerated degradation rate. In this case, the PMS activation path was altered, and the contributions of OH and 1O 2 were largely improved in comparison with SO 4 −. Generally, the metal leaching was worsened due to the lack of ligand protection on coordinately unsaturated metal sites. Fortunately, the PPy shell was compacted and the pore size on shell was narrowed during the heat-treatment, resulting in the suppression effect on outward diffusion of leached metal ions. Therefore, improving catalytic activity and lowering metal leaching were simultaneously realized in the CUMSs-PBA@PPy nanoreactor. [ABSTRACT FROM AUTHOR]

Fenton/photo-Fenton reaction was limited by slow Fe3+/Fe2+ cycle, low H 2 O 2 activation efficiency, and narrow applicable pH range. Here, Fe atoms doped MoS 2 (Fe–MoS 2) with abundant of low-valence Moδ+ (0 < δ < 4) was prepared. Benefiting from the powerful reduction capacity of Moδ+, the rate-limiting step of Fe3+ reduction was significantly accelerated. Nearly 100% of H 2 O 2 utilization efficiency was realized. Importantly, 90% of H 2 O 2 was effectively activated to be •OH. As a result, tetracycline degradation rate in photo-Fenton reaction catalyzed by Fe–MoS 2 was 5.8 and 4.2 times higher than those of MoS 2 and Fe–MoS 2 -Hyd (prepared by hydrothermal reaction). In comparison with MoS 2 and Fe–MoS 2 -Hyd whose efficient work range were limited in acidic condition, Fe–MoS 2 was a pH-universal catalyst (pH = 2.6–14.0) by taking advantage of the exposed Moδ+ and photoinduced electrons, largely improving the environmental tolerance. This work simultaneously addressed three bottlenecks in Fenton/photo-Fenton reaction, and provided a new strategy for the preparation of catalysts with powerful catalytic performance and high environmental adaptability. Low-valence Moδ+ sites were successfully exposed on Fe atoms doped MoS 2 surface. Benefiting from their powerful reduction capacity, the Fe3+/Fe2+ cycle rate was accelerated, the H 2 O 2 utilization efficiency and activation efficiency were maximized, and the applicable pH range was extended in photo-Fenton reaction. [Display omitted] • Fe–MoS 2 with abundant of exposed Moδ+ sites is prepared via surface engineering. • Moδ+ sites are favorable to generate Fe2+ sites and lower activation barriers of H 2 O 2. • Rate-limiting step, Fe3+/Fe2+ cycle, is accelerated by powerful reducibility of Moδ+. • 100% of H 2 O 2 utilization efficiency and 90% of activation efficiency are realized. • Applicable pH range of Fe–MoS 2 is extended to 2.6–14.0, wider than reference samples. [ABSTRACT FROM AUTHOR]

A new luminescence Cd(II)-MOF (1) ([Cd 3 (BTC) 2 (TPT)(H 2 O) 2 ]·4H 2 O, TPT = tris(4-pyridyl)triazine, H 3 BTC = 1,3,5-benzenetricarboxylic acid) was successfully synthesized under solvothermal conditions. 1 contains 3D framework which consist of Cd atoms and btc3− anions with the large channels along c axis. Then, tpt ligands locate in the channels by utilizing three N atoms to bridge two Cd1 atoms and one Cd2 atom. 1 not only possesses remarkable thermal stability, but also can steadily exist in different organic solvents and various acid/base solutions (pH = 3–12). Moreover, 1 can detect 2,4,6-trinitrophenol (TNP) and chromate (CrO 4 2−/Cr 2 O 7 2−) anions with high selectivity and sensitivity in water via the luminescent quenching. The detection limits of 1 for TNP and CrO 4 2−/Cr 2 O 7 2− are 6.23 μM and 2.13 μM/2.87 μM. The mechanism of TNP luminescence quenching may be attributed to photoinduced electron transfer and resonance energy transfer, and CrO 4 2−/Cr 2 O 7 2− quenching involves resonance energy transfer and competitive absorption of light. Additionally, 1 has the great anti-interference ability and repeatability for detecting TNP and CrO 4 2−/Cr 2 O 7 2−, which can display the feasibility of this material as a stable luminescent probe in aqueous system. Unlabelled Image • A new Cd(II)-MOF (1) was synthesized by solvothermal method based on TPT and H 3 BTC. • 1 possesses remarkable thermal and acid/base stability. • 1 can detect TNP and CrO 4 2−/Cr 2 O 7 2− with high selectivity and sensitivity in water. • 1 exhibits the great anti-interference ability and repeatability. [ABSTRACT FROM AUTHOR]