Remediation Of Organic Pollutants Research Articles

Electron-transfer based selective oxidation of organic pollutants via N-doped biochar activated peroxydisulfate: Important role of oxidation potential

For persulfate-based advanced oxidation process, the non-radical pathway is an important route due to the selective oxidation of pollutants and its strong tolerance to complex water bodies. However, the selective oxidation mechanism of organic pollutants needs further elaboration. Herein, we demonstrate a facile hydrothermal pretreatment and high-temperature carbonization route to synthesize the nitrogen-doped porous biochar (NHBC-1). Owing to the well-developed hierarchical porous structure, the created internal active defects, and tailored nitrogen dopants, the NHBC-1 catalyst exhibited excellent catalytic activity for peroxydisulfate (PDS) activation. The results show that pyridinic N facilitated the adsorption of PDS on NHBC-1 to form the highly active NHBC-PDS* complex. Meanwhile, graphitic N and the defective structures promoted the electron-transfer process, thus allowing the efficient catalytic performance of the NHBC/PDS system for phenol oxidation via an electron-transfer dominated pathway. In addition, the system exhibited versatile applicability for the remediation of various organic pollutants in different actual water matrices with wide pH adaptability and satisfactory mineralization efficiency. More importantly, the selective oxidation mechanism of organic contaminants was revealed. Specifically, only the pollutant with oxidation potential lower than that of the NHBC-PDS* complex (0.91 V) can be effectively eliminated. This study not only provides a facile route for the rational designing of a cost-affordable biochar catalyst for PDS activation, but also offers valuable insights into the understanding of selective oxidation of organic contaminants via an electron-transfer dominated pathway.

Zircon-Type CaCrO4 Chromite Nanoparticles: Synthesis, Characterization, and Photocatalytic Application for Sunlight-Induced Degradation of Rhodamine B.

The degradation of organic dye pollutants is a critical environmental issue that has garnered significant attention in recent years. To address this problem, we investigated the potential of CaCrO4 chromite (CCO) as a photocatalyst for the degradation of cationic and anionic dye solutions under sunlight irradiation. CaCrO4 was synthesized via a sol-gel auto-combustion route and sintered at 900 °C. The Rietveld refined XRD profile confirmed the zircon-type structure of CaCrO4 crystallized in the tetragonal unit cell with I41/amd space group symmetry. The surface morphology of the sample was investigated by field emission scanning electron microscopy (FESEM), which revealed the polyhedral texture of the grains. Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) studies were carried out to analyze the elemental composition and chemical states of the ions present in the compound. Fourier transform infrared (FT-IR) spectroscopy analysis revealed the vibrational modes corresponding to the tetrahedral and dodecahedral metal oxide bonds. The optical band gap was approximated to be in the range of 1.928 eV by using the Tauc relation. The CaCrO4 catalyst with different contents (5, 20, 35, and 50 mg) was investigated for its photocatalytic performance for the degradation of RhB dye solution under sunlight irradiation using a UV-Vis spectrometer over the experimental wavelength range of 450-600 nm. The degradation efficacy increased from 70.630 to 93.550% for 5-35 mg and then decreased to 68.720% for 50 mg in 140 min under visible light illumination. The comparative study demonstrates that a higher degradation rate was achieved for cationic than anionic dyes in the order RhB > MB > MO. The highest deterioration (93.80%) was achieved for the RhB dye in 140 min. Equilibrium and kinetic studies showed that the adsorption process followed the Langmuir isotherm and pseudo-second-order models, respectively. The maximum adsorption capacity of 21.125 mg/g was observed for the catalyst concentration of 35 mg. From the cyclic test, it has been observed that the synthesized photocatalyst is structurally and morphologically stable and reusable. The radical trapping experiment demonstrated that superoxide and hydroxyl radicals were the primary species engaged in the photodegradation process. A possible mechanism for the degradation of RhB has been proposed. Hence, we conclude that CaCrO4 can be used as an efficient photocatalyst for the remediation of organic dye pollutants from the environment.

Enhanced performance of heterogeneous fenton-like Co-Cu catalysts for metronidazole degradation: Ethylene glycol as a superior fabrication solvent

This study addresses the gap in understanding of fabrication solvent influence on Cu-Co catalyst performance for MNZ degradation. By synthesizing recyclable Cu-Co catalysts using the co-precipitation method, the study investigates the impact of ethylene glycol (EG) solvent compared to conventional water (H2O) solvent. The optimized operational parameters resulted in stable and high MNZ degradation efficiency (above 90 % removal) with twice-feeding of 1600 ppm H2O2, pH ∼7.15, and 50 °C. The use of EG solvent enhances catalyst surface area, exposing more active sites with higher Cu+ and Cu2+ content, which incorporated in CoO6 environment with promoted redox property to facilitate H2O2 reaction and •OH production. This research contributes valuable insights into catalyst design and optimization, highlighting the potential of EG solvent for industrial application in antibiotic organic pollutant remediation.

Key Role of Corncob Based-Hydrochar (HC) in the Enhancement of Visible Light Photocatalytic Degradation of 2,4-Dichlorophenoxyacetic Acid Using a Derivative of ZnBi-Layered Double Hydroxides.

A superior heterojunction of HC-ZnBi-LDO was synthesized in two steps, namely hydrothermal carbonization, followed by co-precipitation. The 2% HC-ZnBi-LDO heterojunction photocatalysts could degrade over 90.8% of 30 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) using 1.0 g/L of the catalyst after 135 min of visible light exposure at pH 4. The activity of 2% HC-ZnO-LDO was remarkably stable. Approximately 86.4-90.8% of 30 mg/L 2,4-D was degraded, and more than 79-86.4% of TOC was mineralized by 2% HC-ZnBi-LDO at pH 4 after 135 min of visible light exposure during four consecutive cycles. The rapid separation and migration of charge carriers at the interfaces between HC and ZnBi-LDO were achieved within 2% HC-ZnBi-LDO. Moreover, the electron acceptor characteristic of HC in 2% HC-ZnBi-LDO caused the recombination of charge carriers to decrease significantly, thus generating more reactive radicals, such as hydroxyl radicals (OH●) and superoxide radicals (O2●-). These results demonstrate that the novel 2% HC-ZnBi-LDO is a superior photocatalyst for the remediation of hazardous organic pollutants.

Recent Advances in Copper-Based Materials for Sustainable Environmental Applications

In recent years, copper-based nanomaterials have gained significant attention for their practical applications due to their cost-effectiveness, thermal stability, selectivity, high activity, and wide availability. This review focuses on the synthesis and extensive applications of copper nanomaterials in environmental catalysis, addressing knowledge gaps in pollution management. It highlights recent advancements in using copper-based nanomaterials for the remediation of heavy metals, organic pollutants, pharmaceuticals, and other contaminants. Also, it will be helpful to young researchers in improving the suitability of implementing copper-based nanomaterials correctly to establish and achieve sustainable goals for environmental remediation.

First-rate photocatalytic degradation of wastewater pollutants and antibacterial activities and H2 evolution of hierarchical WO3 embedded BiOCl/g-C3N4 nanocomposites

Highly efficient and stable WO3-embedded hierarchical BiOCl/g-C3N4 (WBG) composites have been synthesized by a two-step solvothermal route. Phase identification and other structural and microstructural parameters are evaluated by analyzing the XRD pattern of respective composites employing the Rietveld refinement technique. HRTEM images reveal that BiOCl and WO3 nanoparticles of size 20–25 and 4–6 nm are embedded uniformly on the surface of g-C3N4 nanosheets respectively. The nanocomposites offered outstanding photocatalytic performance by showing degradation of colored dyes, colorless pollutants, tetracycline antibiotics and reduction of Cr (VI). About 95% of RhB dyes within 8 min, ∼91% phenol within 150 min, ∼85% tetracycline (TC) within a record 20 min have been degraded, and 98% Cr (VI) reduced within 10 min from wastewater under sunlight irradiation in the presence of the WBG3 nanocomposite. In addition, the WBG3 nanocomposite shows a significant photocatalytic H2 production rate of 2 mmol.h−1 g−1. Apart from that, the growth of gram-positive and gram-negative pathogenic bacteria is notably inhibited by WBG nanocomposite, comparable to the same concentration of the pure drug. This work provides a strong framework to fabricate future-generation photocatalysts for the remediation of organic pollutants and heavy metals and for producing solar light-driven hydrogen evolution.

Engineering sulfuric acid-pretreated biochar supporting MnO2 for efficient toxic organic pollutants removal from aqueous solution in a wide pH range

Manganese dioxides (MnO2) and biochar materials are both desirable candidates for environmental remediation of toxic organic pollutants (TOPs) in water due to wide availability and environmental-friendly. In practical application, however, MnO2 suffers from low redox activity owing to deprotonation, while biochar is subject to limited removal capacity. Herein, a difunctional engineering sulfuric acid-pretreated biochar supporting MnO2 composite (MBC-A) was firstly synthesized and optimized to remove various TOPs from aqueous solution. Specifically, sulfuric acid not only served as an active agent to improve the specific surface area of biochar for improvement of adsorption capacity and more MnO2 loading, but also facilitated the introduction of sulfonic acid groups (-SO3H) as an internal proton reservoir to inhibit inactivation of MnO2 due to deprotonation in alkaline. Thanks to adsorption and oxidation, MBC-A showed excellent removal capacity (214.9 mg/g) and fast reaction kinetics (360 min) for tetracycline (TC), exceeding precursor and other materials reported in literature. Importantly, the effective operation pH range of MBC-A was broadened to 1–13 with the help of buffering capacity of –SO3H groups. The dominant driving force of adsorption were π-π interaction and hydrogen bond; while reactive oxidative species were mainly ascribed to singlet oxygen (1O2), hydroxyl radical (·OH) and reactive Mn3+. The possible reactive sites and pathway were investigated by combining experimental results with density functional theory (DFT) calculation. Further, the results of multiple cyclic runs, removal in real river water and toxicity assessment demonstrated well reusability, high environmental security, and excellent practical applicability of MBC-A.

Piezo-plasmon phototronically enhanced direct solar-chemical translations from Au decorated perovskite BiFeO3 sea urchin-like 3D nanostructures

Bismuth ferrite-based oxide nanostructures were chemically processed to offer an effective solution for the growing energy crisis and environment pollution by employing them as photoelectrodes for water splitting reactions and remediation of organic pollutants through photocatalysis. The influence of plasmonic effects via gold (Au) incorporating the physicochemical properties and their resulting impact on the application performance has been studied systematically. The processed materials were examined using X-ray diffraction (XRD), absorbance, and transmission electron microscopic instruments. Au interaction in the host BFO nanoparticle surface was affirmed through an in-depth examination of their photoelectron spectroscopic data. Plasmonic effect was also visualized in the absorbance spectra along with a significant change in the optical spectrum on Au decoration. Photoluminescence spectra approved the quality of defect states to be significantly influenced by the BFO nanoparticles and the Au nanoparticles influenced charge transmigration and separation. Enhanced photocatalytic and photoelectrochemical performance from the Au-decorated BFO nanostructures was evaluated through comparative analysis of pristine BFO. Time-dependent photocurrent density studies also proved the stability of processed photoelectrode materials in efficient water splitting via Au nanoparticles, which actually enhanced the charge transfer efficiency by offering improved conductivity as studied via Nyquist plots. The piezophotocatalysis activity of the nanocomposite exhibited a high degree of degradation of organic pollutants and better hydrogen production from water splitting reaction upon direct sunlight illumination.

Natural hematite as low-cost auxiliary material for improving soil remediation by in-situ microbial community.

Microbial-mineral interaction has a broad application prospect in the field of environmental remediation of organic pollutants. However, the disadvantages of long repair cycle and low repair rate limit its industrial application. In this study, natural hematite was used as an auxiliary material for soil remediation in a bio-electrochemical system. It was found that the power density of soil microbial fuel cell (SMFC) system composed of 2.0mm hematite was 2.889 mW/m2, which is 2.7 times compared with the blank group (1.068 mW/m2) in the particle size optimization experiment. A similarly increased power density (1.068 to 2.467 mW/m2) was observed when the hematite content changed from 0 to 20% in the concentration optimization experiment. Under 20% and 2.0-mm hematite condition, the phenol removal rate was closed to 99% after 7days, which is 1.9-folds compared with blank control (53%). These results suggest that addition of hematite enhances soil porosity and conductivity, and increases the number of electron acceptors in soil. These findings inspire that this economic and abundant natural mineral is expected to be a potential auxiliary material in the field of soil organic pollutant purification, and expand the understanding of interactions between hematite and microorganisms in nature.

Heterogeneous electro-Fenton system with Co/N-GO modified cathode to degrade phenolic organic pollutants: The main role of singlet oxygen

Heterogeneous electro-Fenton (hetero-EF) system has attracted much attention for the removal of refractory organic pollutants. In this study, hetero-EF for phenol degradation was constructed to use cobalt and nitrogen co-doped graphene (Co/N-GO) modified cathode. The microstructure and composition of the modified cathode material were explored using SEM, TEM, XPS, and XRD. Systematic investigation of the effects of various factors on phenol removal showed that the phenol removal rate could reach 97.00 % in the hetero-EF system by Co/N-GO within 4 h, and the substrate could be removed well in a wide pH range (3–9). The phenol removal rate was still up to 90.71 % after eight consecutive reaction cycles. Combined with the quenching test and EPR analysis, singlet oxygen (1O2) played a major role in the degradation of phenol. Further research revealed that •OH and •O2− were not only involved in oxidative degradation of pollutants, but also contributed to the production of 1O2. Meanwhile, dissolved oxygen (DO) also participated in the formation of 1O2. The study is beneficial to further develop the potential of hetero-EF system for environmental organic pollution remediation.

Mediator‐Free S‐Scheme S‐C3N4/Ce2Zr2O7 Heterojunction Hybrid Material for Effective Photocatalytic Degradation of Persistent Organic Pollutants Under Visible Light

AbstractIn this study, we demonstrated a Step‐scheme (S‐scheme) based S‐C3N4/Ce2Zr2O7 (SCN/CZ) organic‐inorganic heterostructure, which was synthesized by a facile wet chemical route. The photocatalyst was highly efficient for the remediation of organic pollutants (POPs), namely 2,4‐dichlorophenol (2,4‐DCP, 20 ppm), 4‐chlorophenol (4‐CP, 20 ppm), and phenol (20 ppm) via dehalogenation under visible light (λ≥420 nm). Our finding reveals that a 20 wt.% S‐C3N4 on the surface of the SCN/CZ hybrid is an optimum requirement for potential catalytic activity. We achieve excellent photocatalytic performances i. e., 94 % for 2,4‐DCP, 92 % for 4‐CP, and 90 % for phenol removal, respectively. It was identified that superoxide and hydroxyl radicals (O2⋅− and ⋅OH) are diligently participating in the reaction medium. However, the content of O2⋅− species is more, which we have quantified as ∼66 μM when 20 % SCN/CZ is used. Furthermore, we have established the reaction pathways via an S‐scheme mechanism, which has great importance for photocatalysis. The prepared catalyst is highly stable and reusable for more than five cycles. The work presented here can contribute to the new perspective for pollutant removal via the dehalogenation route over the S‐C3N4/Ce2Zr2O7 surface.

Oxygen-enriched vacancy Co2MnO4 spinel catalyst activated peroxymonosulfate for degradation of phenol: Non-radical dominated reaction pathway

Spinel is a desirable catalyst for active peroxymonosulfate (PMS) to degrade organic pollutants in complex water matrix. In this study, spinel-type Co2MnO4 catalyst were successfully synthesized and employed as an efficient PMS activator for the degradation of phenol in water (up to 100 % within 45 min, degradation rate constant (k) is 0.076 min−1) at initial PH of 6.3. The excellent catalytic activity of Co2MnO4/PMS system was found to be attributed to its unique porous structure, oxygen vacancies and the synergistic effect of Co and Mn. Sulfate radicals (SO4−) and singlet oxygen (1O2) all contributed to phenol degradation, and 1O2, a non-radical pathway mainly provided by oxygen vacancies of Co2MnO4, is the dominant reactive species in the activation system. The Co2MnO4/PMS system had good resistance to the common inorganic anions (Cl−, HPO42−, HCO3− and NO3−) and exhibited great reusability due to the strong Co/Mn interaction. Finally, the phenol degradation mechanism in Co2MnO4/PMS system was also proposed based on the detected intermediates by GC–MS. Overall, the system composed of oxygen-enriched vacancy Co2MnO4 spinel catalyst and PMS has good degradation efficiency and is suitable for the remediation of organic pollutants in wastewater.

Permanganate activation by glucose-derived carbonaceous materials for highly efficient degradation of phenol and p-nitrophenol: Formation of hydroxyl radicals and multiple roles of carbonaceous materials

Owing to its inertness toward refractory organic pollutants and the release of Mn2+, the use of permanganate was limited in soil and groundwater remediation. The present study proposed an improvement strategy based on glucose-derived carbonaceous materials, which enhanced the potential of permanganate degrading organic pollutants. The glucose-derived carbonaceous material with 1000 °C charring temperature was named C1000, which was exploited in activating KMnO4 for the elimination of refractory organic contaminants. The addition of C1000 in the KMnO4 system triggered the degradation of refractory p-nitrophenol and quicken phenol degradation. Unlike the detection of Mn(III) species in a solo KMnO4 system, the presence of C1000 facilitated the formation of •OH in the KMnO4 system, which was confirmed by the use of quenchers such as methanol, benzoic acid, tertiary butanol, and carbonate. Additionally, the glucose-derived carbonaceous material played multiple roles in improving the performance of permanganate, including the enrichment of organic pollutants, donation of electrons to permanganate, and acting as an electron shuttle to facilitate the oxidation of organic pollutants by permanganate. The study's novel findings have the potential to expand the use of permanganate in the remediation of organic pollutants.

Novel in situ synthesis of quaternary core–shell metallic sulfide nanocomposites for degradation of organic dyes and hydrogen production

Abstract Environmental remediation of toxic organic pollutants on catalytic degradation has gained much attention. Organic dyes and fossil fuels as pollutants are the two major problems nowadays. The efficient and targeted eradication of organic dye from water systems is a critical global concern for the treatment of both drinking water and wastewater. In this study, ZnO–ZnS–CdO–CdS quaternary core–shell nanocomposites (NCs) were synthesized using Ricinus communis as a stabilizing agent and hydrazine hydrate as a reducing agent. UV-visible spectroscopy and photoluminescence confirmed the formation of NCs. Fourier transform infrared spectroscopy confirmed the presence of functional groups, while scanning electron microscopy analysis revealed that the morphology of nanomaterials was spherical and poly distributed. X-ray powder diffraction confirmed the crystalline nature of prepared samples. The prepared nanocatalysts were used in the production of hydrogen gas from green sources of the Brassica campestris leaf extract and the degradation of Congo red and methyl red dyes. Overall, the photocatalytic performance of NCs and their design was successful. The prepared catalysts were not only active in the degradation of a single substrate but also in the degradation of a mixture of dyes.

Photocatalytic performance of pyrochar and hydrochar in heterojunction photocatalyst for organic pollutants degradation: Activity comparison and mechanism insight

Biochar-based photocatalysts have attracted widespread attention for the remediation of organic pollutants in water. Herein, we have successfully prepared Bi2WO6/TiO2 heterojunction photocatalysts modified by pyrochar (HC) and hydrochar (PC) to illustrate the role of two different biochar in the system. HC had a higher O elemental content and a larger specific surface area compared to PC. Under the visible light irradiation, PC with persistent radicals could facilitate the production of ·OH during the photocatalytic reaction, while the HC promoted the production of ·O2– due to the presence of oxygen-containing functional groups, which made the Bi2WO6/TiO2/HC exhibit superior photocatalytic property for sulfathiazole (STZ) degradation. The results of characterization revealed that PC could act as an electron shuttle to facilitate photo-excited electron transfer. For HC, the oxygen-containing functional groups (OFGs) could act as photosensitizers while the particles with rod structure function as an electron carrier, which could synergistically promote the photocatalytic degradation of sulfathiazole with Bi2WO6/TiO2 heterojunction. Surprisingly, the real water experiments, luminescent bacterial test, and Toxicity Estimation Software Tool program indicated that Bi2WO6/TiO2/HC and Bi2WO6/TiO2/PC exhibited excellent practicality and reduced toxicity, which could provide a prospering strategy and insight into the design of efficient biochar-based photocatalysts for environmental remediation.

Iron-organic frameworks as effective fenton-like catalysts for peroxymonosulfate decomposition in advanced oxidation processes

Although Fenton-like reactions have been extensively used to treat various organic contaminants in wastewaters (oily wastewaters, landfill leachate, denitrification with Fenton oxidized non-degradable large molecular organic pollutants, and removal of phosphorus, etc.), the difficulty in catalyst recovery and the instability of catalytic activity limit their practical application. Herein, iron atoms were inserted in a metal-organic framework (FeNC) with dual reaction sites as highly reactive and stable electro-Fenton-like catalysts for the catalytic oxidation of organic pollutants via the electro-Fenton-like activation reaction of peroxymonosulfate (PMS) with fractional leaching of metal ions. Experiments and density functional theory (DFT) calculations indicate that FeNC with FeN4 and Fe–Fe active sites can rapidly deliver electrons for PMS dissociation. Further, an electrolysis reactor was constructed for the on-site generation of reactive oxygen species, which can stably and continuously purify various organic wastewaters. The combined use of an electrolysis reactor and magnetic catalyst in the current study provides a direction for the long-term remediation of organic pollutants on an industrial scale.

Effects of functional group loss on biochar activated persulfate in-situ remediation of phenol pollution in groundwater and its countermeasures

Biochar is considered a good activator for use in advanced oxidation technology. However, dissolved solids (DS) released from biochar cause unstable activation efficiency. Biochar prepared from saccharification residue of barley straw (BC-SR) had less DS than that prepared directly from barley straw (BC–O). Moreover, BC-SR had a higher C content, degree of aromatization, and electrical conductivity than BC-O. Although the effects of BC-O and BC-SR on activation of Persulfate (PS) to remove phenol were similar, the activation effect of DS from BC-O was 73% higher than that of DS from BC-SR. Moreover, the activation effect of DS was shown to originate from its functional groups. Importantly, BC-SR had higher activation stability than BC-O owing to the stable graphitized carbon structure of BC-SR. Identification of reactive oxygen species showed that SO4•-, •OH, and 1O2 were all effective in degradation by BC-SR/PS and BC-O/PS systems, but their relative contributions differed. Furthermore, BC-SR as an activator showed high anti-interference ability in the complex groundwater matrix, indicating it has practical application value. Overall, this study provides novel insight that can facilitate the design and optimization of a green, economical, stable, and efficient biochar-activated PS for groundwater organic pollution remediation.

Influence of organic cosolvents on hexabromobenzene degradation in solution by montmorillonite-templated subnanoscale zero-valent iron

Organic cosolvents are commonly used to increase the dissolution of poorly water-soluble organic pollutants into aqueous solutions during environmental remediation. In this study, the influences of five organic cosolvents on hexabromobenzene (HBB) degradation catalyzed by one typical reactive material montmorillonite-templated subnanoscale zero-valent iron (CZVI) were investigated. The results demonstrated that all cosolvents promoted HBB degradation but the degree of promotion was different for different cosolvents, which was associated with inconsistent solvent viscosities, dielectric constant properties, and the extent of interactions between cosolvents with CZVI. Meanwhile, HBB degradation was highly dependent on the volume ratio of cosolvent to water, which increased in the range of 10%–25% but persistently decreased in the range of more than 25%. This might be due to the fact that the cosolvents increased HBB dissolution at low concentrations but reduced the protons supplied by water and the contact between HBB with CZVI at high concentrations. In addition, the freshly-prepared CZVI had higher reactivity to HBB than the freeze-dried CZVI in all water-cosolvent solutions, probably because freeze-drying reduced the interlayer space of CZVI and thus the contact probability between HBB and active reaction sites. Finally, the CZVI-catalyzed HBB degradation mechanism was proposed as the electron transfer between zero-valent iron and HBB, which led to the formation of four debromination products. Overall, this study provides helpful information for the practical application of CZVI in the remediation of persistent organic pollutants in the environment.

Recent Advances in MOF-Based Materials for Remediation of Heavy Metals and Organic Pollutants: Insights into Performance, Mechanisms, and Future Opportunities

In recent years, heavy metals and organic pollutants have become two major obstacles to maintaining the ecological environment. Thus, choosing efficient and environmentally friendly methods and materials to remediate heavy metals and organic pollution has become a hot research topic. Porous metal–organic frameworks (MOFs) and their composites or derivatives can be used as ideal adsorbents and catalytic materials because of their unique structures and functions. This work reviews the research progress on MOF-based materials in the remediation of the water environment in the past decade. The MOF-based materials discussed here mainly include MOF composites obtained by fabrication and MOF derivatives obtained by pyrolysis. Both MOF composites and MOF derivatives are optimized materials that exhibit adsorption or catalytic performance superior to the pristine MOFs. Additionally, the interactions and mechanisms between the MOF-based materials and different heavy metals or organic pollutants are discussed in detail. Finally, some problems or defects of the MOF-based materials are also proposed considering the materials’ economic efficiency, stability and safety. There is still a long way forward for the real application of MOF-based materials. Further efforts are also needed to explore and expand the environmental remediation scope of MOF-based materials.

Natural manganese ores for efficient removal of organic pollutants via catalytic peroxymonosulfate‐based advanced oxidation processes

AbstractPeroxymonosulfate‐based advanced oxidation processes (PMS‐AOPs) for in situ persistent organic pollutant (POP) remediation in aqueous solutions can be a promising technology. However, this technology is constrained by its high toxicity and cost of metal oxide and non‐metal catalysts for PMS activation. Here, we investigated the catalytic performance of a widely available natural mineral, manganese ore (MO), for PMS activation. A series of natural MO samples in an aqueous solution were prepared via the Fenton‐like reaction. The samples' crystalline structure, surface morphology, textural properties, and other surface characteristics of the selected MO were systematically characterized. The effects of PMS concentration and process parameters on the degradation performance of four chosen model pollutants, that is, phenol, tetrabromobisphenol A (TBBPA), rhodamine B (RhB), and methylene blue (MB), were evaluated. The experimental results showed that natural MO increased catalytic activity and enhanced the PMS oxidation processes, with 98%, 90%, and 75% removal efficiencies on phenol, TBBPA, and RhB, respectively, within 1.5 h. The reduction in the initial pH solution from 10 to 7 and the increase in temperature from 15 to 45°C enhanced the MB degradation rate (decolorization) by 55 and 46%, respectively, within 2 h. During the PMS activation process, SO4•−, •OH, and 1O2 species were generated, but only SO4•− and •OH radicals with strong oxidative potentials contributed to the catalytic degradation. The dissolved metals from the experiments were found well within the limit of drinking water standards, verifying that the MO + PMS catalytic system is suitable for commercial applications. This work provides insights into the development potential and prospects of using natural minerals for PMS activation and POP degradation, which can accelerate their industrial applications.