An innovative triple interface reinforced photocatalytic system based on BiOCl/BaTiO3@Co-BDC-MOF composite for the simultaneous detoxification of Cr(VI) and sulfamethoxazole

The development of effective photocatalysts for the reduction of Cr(VI) and the degradation of antibiotics remains a challenge. The present work reports the development of a novel heterojunction composite material, BiOCl/BaTiO3@Co-BDC-MOF (BOC/BTO@Co-MOF), based on solvothermal techniques. To characterize the surface and bulk features of the material, techniques such as FE-SEM, HR-TEM, BET/BJH, XPS, FT-IR, p-XRD, and UV-Vis-DRS were used. Based on the results, the BiOCl/BaTiO3 nanocomposites are uniformly dispersed on the rod-shaped Co-BDC MOF, resulting in a layered texture on the surface. A further advantage of the composite structure is the strong interfacial enhancement facilitating the separation of photoexcited electron-hole pairs. Also, compared to its pristine counterparts, the heterostructure material exhibited excellent surface area and pore properties. The photocatalytic efficiency towards reduction and degradation of Cr(VI)/SMX pollutants were evaluated by optimizing various analytical parameters, such as pH, catalytic loading concentrations, analyte concentration, and scavenger role. The specially designed BOC/BTO@Co-MOF composite achieved a 96.5% Cr(VI) reduction and 98.2% SMX degradation under 60.0-90.0 min of visible light illumination at pH 3.0. This material is highly reusable and has a six-time recycling potential. The findings of this study contribute to a better understanding of the efficient decontamination of inorganic and organic pollutants in water purification systems.

Multi-metallic MOF based composites for environmental applications: synergizing metal centers and interactions

The escalating threat of environmental issues to both nature and humanity over the past two decades underscores the urgency of addressing environmental pollutants. Metal-organic frameworks (MOFs) have emerged as highly promising materials for tackling these challenges. Since their rise in popularity, extensive research has been conducted on MOFs, spanning from design and synthesis to a wide array of applications, such as environmental remediation, gas storage and separation, catalysis, sensors, biomedical and drug delivery systems, energy storage and conversion, and optoelectronic devices, etc. MOFs possess a multitude of advantageous properties such as large specific surface area, tunable porosity, diverse pore structures, multi-channel design, and molecular sieve capabilities, etc., making them particularly attractive for environmental applications. MOF-based composites inherit the excellent properties of MOFs and also exhibit unique physicochemical properties and structures. The tailoring of central coordinated metal ions in MOFs is critical for their adaptability in environmental applications. Although many reviews on monometallic, bimetallic, and polymetallic MOFs have been published, few reviews focusing on MOF-based composites with monometallic, bimetallic, and multi-metallic centers in the context of environmental pollutant treatment have been reported. This review addresses this gap by providing an in-depth overview of the recent progress in MOF-based composites, emphasizing their applications in hazardous gas sensing, electromagnetic wave absorption (EMWA), and pollutant degradation in both aqueous and atmospheric environments and highlighting the importance of the number and type of metal centers present. Additionally, the various categories of MOFs are summarized. MOF-based composites demonstrate significant promise in addressing environmental challenges, and this review provides a clear and valuable perspective on their potential in environmental applications.

Noteworthy synthesis strategies and applications of metal-organic frameworks for the removal of emerging water pollutants from aqueous environment

17 global Sustainable Development Goals (SDGs) were established through the adoption of the 2030 Agenda for Sustainable Development by all United Nations members. Clean water and sanitation (SDG 6) and industry, innovation, and infrastructure (SDG 9) are the SDGs focus of this work. Of late, various new companies delivering metal-organic frameworks (MOFs) have blossomed and moved the field of adsorption utilizing MOFs to another stage. Inside this unique circumstance, this article aims to catch recent advancements in the field of MOFs and the utilizations of MOFs relate to the expulsion of arising contaminations that present huge difficulties to water quality because of their steadiness and possible damage to environments and human wellbeing. Customary water treatment techniques regularly neglect to eliminate these poisons, requiring the advancement of novel methodologies. This study overviews engineering techniques for controlling MOF characteristics for better flexibility, stability, and surface area. A current report on MOFs gathered new perspectives that are amicably discussed in emergent technologies and extreme applications towards environmental sectors. Various applications in many fields that exploit MOFs are being fostered, including gas storage, fluid separation, adsorbents, catalysis, medication delivery, and sensor utilizations. The surface area of a wide range of MOFs ranges from 103 to 104 m2/g, which exceeds the standard permeability of several material designs. MOFs with extremely durable porosity are more significant in their assortment and variety than other classes of porous materials. The work outlines the difficulties encountered in the synthesis steps and suggests ways to make use of MOFs' value in a variety of contexts. This caters to creating multivariate systems enclosed with numerous functionalities, leading to the synthesis of MOFs that offer a synergistic blend of in-built properties and exclusive applications. Additionally, the MOF-related future development opportunities and challenges are discussed.

Advances in metal-organic frameworks for water remediation applications

Rapid industrialization and agricultural development have resulted in the accumulation of a variety of harmful contaminants in water resources. Thus, various approaches such as adsorption, photocatalytic degradation and methods for sensing water contaminants have been developed to solve the problem of water pollution. Metal-organic frameworks (MOFs) are a class of coordination networks comprising organic-inorganic hybrid porous materials having organic ligands attached to inorganic metal ions/clusters via coordination bonds. MOFs represent an emerging class of materials for application in water remediation owing to their versatile structural and chemical characteristics, such as well-ordered porous structures, large specific surface area, structural diversity, and tunable sites. The present review is focused on recent advances in various MOFs for application in water remediation via the adsorption and photocatalytic degradation of water contaminants. The sensing of water pollutants using MOFs via different approaches, such as luminescence, electrochemical, colorimetric, and surface-enhanced Raman spectroscopic techniques, is also discussed. The high porosity and chemical tunability of MOFs are the main driving forces for their widespread applications, which have huge potential for their commercial use.

Tuning of interfacial HGO@CLS nanohybrid S-scheme heterojunction with improved carrier separation and photocatalytic activity towards RhB degradation

Herein, we premeditated and invented the innovative hybrid photocatalyst 2D/2D CuLa2S4 on holey graphene oxide (HGO) (HGO@CLS) via the hydrothermal method. Electrochemical techniques demonstrate the action of HGO in the HGO@CLS photocatalyst as an effective medium for electron transfer. Combining bimetallic sulfides on porous HGO synergistically provides a higher negative conduction band edge (-0.141 V), greater photo response (10.8 mA/cm2), smaller charge transfer resistance (Rct = 1.79Ω), and lower photoluminescence (PL) spectral intensity. According to our research, the catalytic recitals are sped up when HGO is assimilated into CLS photocatalyst hetero-junction. Additionally, it lowers the reassimilation rate due to the combined mesh nanostructures and functionality of CLS and HGO. UV-Vis DRS, Mott-Schottky, PL, and Electrochemical impedance spectra (EIS) results manifested that the CuLa2S4/HGO makes the spatial separation competent and transference of charge carriers due to the photon irradiation and exhibits superior photocatalytic ability. Electron spin resonance (ESR) analysis confirmed that •OH and h+ were the predominant radical species responsible for Rhodamine B(RhB) degradation. Moreover, conceivable degradation ways of RhB were deduced according to the identified intermediates which are responsible for the degradation of recalcitrant products. To check the stability of the photocatalyst, revival tests were also carried out. Similarly, the oxidative byproducts created in the deprivation courses were looked at, and a thorough explanation for the mechanism of degradation was given.

High-performance functional cellulose foam fabricated with theoretically optimized imidazolium salts for the efficient removal of ciprofloxacin

With the increasing requirements for sustainable development and environmental protection, the design and development of bio-adsorbent based on the widely sourced cellulose have attracted widespread attention. In this study, a polymeric imidazolium satls (PIMS) functionalized cellulose foam (CF@PIMS) was conveniently fabricated. It was then employed to efficiently remove ciprofloxacin (CIP). Three imidazolium salts containing phenyl groups that can lead to multiple interactions with CIP were elaborately designed and then screened through a combination of molecular simulation and removal experiments to acquire the most significant binding ability of CF@PIMS. Besides, the CF@PIMS retained the well-defined 3D network structure as well as high porosity (90.3 %) and total intrusion volume (6.05 mL g^-1) as the original cellulose foam (CF). Therefore, the adsorption capacity of CF@PIMS reached an astonishing value of 736.9 mg g^-1, nearly 10 times that of the CF. Furthermore, the pH-affected and ionic strength-affected adsorption experiments confirmed that the non-electrostatic interaction took on a critical significance in the adsorption. The reusability experiments showed that the recovery efficiency of CF@PIMS was higher than 75 % after 10 adsorption cycles. Thus, a high-potential method was proposed in terms of the design and preparation of functionalized bio-adsorbent to remove waste matters from samples of the environment.

Co-adsorption and Fenton-like oxidation in the efficient removal of methylene blue by MIL-88B@UiO-66 nanoflowers

Development of binary MOF-on-MOF heterostructures is a research hotspot in MOFs chemistry due to the advantages elicited by a closely connected interface, which may endow more abundant functionality and even broader applications in interface chemistry. A MOF-on-MOF heterostructure was constructed by in situ growth of MIL-88B on the outer surface of UiO-66. The resultant MIL-88B@UiO-66 produced had an interesting flower-like morphology composed of MIL-88B (petal) on tetrahedral UiO-66 (core). The MIL-88B@UiO-66 heterostructure showed adsorption and Fenton-like oxidation abilities, with distinctly improved structural stability in aqueous solution compared with that of single MIL-88B. Methylene blue (MB) was selected as the target molecule to evaluate the adsorption and Fenton-like oxidation activities. The efficiency of total removal of MB was studied systematically under various operating conditions and the influencing factors were optimized. The kinetics of adsorption and catalytic oxidation were simulated to explore the interactions between MB and MIL-88B@UiO-66. The mechanisms of enhanced adsorption and Fenton-like oxidation were suggested. The cyclic removal performance and structural stability of MIL-88B@UiO-66 were also determined.

Degradation of lomefloxacin by MoS2/MIL-53(Fe, Cu) catalyst in heterogeneous electro-Fenton process

A novel heterogeneous catalyst named MoS₂/MIL-53(Fe, Cu) (MMFC) was prepared by hydrothermal method and applied in a heterogeneous electro-Fenton (hetero-EF) system for lomefloxacin (LOM) degradation in this work. Under the optimal conditions of current density 3 mA/cm², catalyst dosage 0.100 g/L, and initial pH 6, 93.5% LOM (2 mg/L) removal efficiency was achieved in the MMFC hetero-EF system within 60 min, indicating an obvious improvement compared with the MIL-53(Fe, Cu) hetero-EF system. The good catalytic activity was attributed to more effective active sites of the catalyst and the conversion of Fe(II)/Fe(III) and Cu(I)/Cu(II) promoted by Mo(IV) in MoS₂, which could be inferred by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) characterizations. The reusability and stability of MMFC were explored based on five cyclic experiments, and the average degradation efficiency reached 73.9%. Furthermore, the hetero-EF system could achieve the total removal of moxifloxacin and tetracycline within 6 min and 40 min, respectively. Quenching experiments revealed that the hydroxyl radicals (·OH) were the main reactive radicals while superoxide radicals (·O₂^-) and singlet oxygen (¹O₂) played a certain part in LOM degradation. Finally, the possible mechanism of the hetero-EF process and LOM degradation pathways were proposed, including substitution, elimination, and cleavage of ring structures. Accounting for good catalytic performance, low preparation cost, and satisfactory versatility, the MMFC exhibited good potential to work as a hetero-EF catalyst for wastewater treatment.

Multi-functional metal-organic frameworks for detection and removal of water pollutions

Water pollutions have caused serious threats to the aquatic environment and human health, it is of great significance to monitor and control their contents in water. Compared with the traditional...

Conversion of scrap iron into ultrafine α-Fe2O3 nanorods for the efficient visible light photodegradation of ciprofloxacin

The present study illustrates a feasible approach of utilizing scrap iron for the synthesis of iron(ii) oxide.

Fabrication of easy separable and reusable MIL-125(Ti)/MIL-53(Fe) binary MOF/CNT/Alginate composite microbeads for tetracycline removal from water bodies

In this investigation, we aimed to fabricate easy separable composite microbeads for efficient adsorption of tetracycline (TC) drug. MIL-125(Ti)/MIL-53(Fe) binary metal organic framework (MOF) was synthetized and incorporated with carbon nanotube (CNT) into alginate (Alg) microbeads to form MIL-125(Ti)/MIL-53(Fe)/CNT@Alg composite microbeads. Various tools including FTIR, XRD, SEM, BET, Zeta potential and XPS were applied to characterize the composite microbeads. It was found that the specific surface area of MIL-125(Ti)/MIL-53(Fe)/CNT@Alg microbeads was 273.77 m2/g. The results revealed that the adsorption of TC augmented with rising CNT proportion up to 15 wt% in the microbeads matrix. In addition, the adsorption process followed the pseudo-second-order and well-fitted to Freundlich and Langmuir models with a maximum adsorption capacity of 294.12 mg/g at 25 ◦C and pH 6. Furthermore, thermodynamic study clarified that the TC adsorption process was endothermic, random and spontaneous. Besides, reusability test signified that MIL-125(Ti)/MIL-53(Fe)/CNT@Alg composite microbeads retained superb adsorption properties for six consecutive cycles, emphasizing its potentiality for removing of pharmaceutical residues.