Environmental pollution and its after-effects have become global concerns in recent years. Among all types of pollution, water pollution has been considered as a major threat in recent years; this problem will be even worse in the near future. In the 21st century, water recycling has become a crucial issue as more regions across the globe are witnessing a water crisis. Detoxification of wastewater via adsorptive removal or photocatalytic degradation for achieving purified and drinkable water has been determined as environmentally benign, energy economic and cost-effective. In this context, porous materials have gained enormous research consideration for detection of contaminants in effluents and for treatment of wastewater. A combination of high porosity, robustness and structural tunibility makes these nanosorbents stand out as materials in environmental remediation. Metal–organic frameworks, covalent organic frameworks and porous organic solids are among the versatile porous materials extensively invest...

Advanced Porous Materials for Sensing, Capture and Detoxification of Organic Pollutants toward Water Remediation

Tens of thousands of metal-organic frameworks (MOFs) have been developed in the past two decades, and only ≈100 of them have been demonstrated as porous and hydrophobic. These hydrophobic MOFs feature not only a rich structural variety, highly crystalline frameworks, and uniform micropores, but also a low affinity toward water and superior hydrolytic stability, which make them promising adsorbents for diverse applications, including humid CO2 capture, alcohol/water separation, pollutant removal from air or water, substrate-selective catalysis, energy storage, anticorrosion, and self-cleaning. Herein, the recent research advancements in hydrophobic MOFs are presented. The existing techniques for qualitatively or quantitatively assessing the hydrophobicity of MOFs are first introduced. The reported experimental methods for the preparation of hydrophobic MOFs are then categorized. The concept that hydrophobic MOFs normally synthesized from predesigned organic ligands can also be prepared by the postsynthetic modification of the internal pore surface and/or external crystal surface of hydrophilic or less hydrophobic MOFs is highlighted. Finally, an overview of the recent studies on hydrophobic MOFs for various applications is provided and suggests the high versatility of this unique class of materials for practical use as either adsorbents or nanomaterials.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/advs.201901758

Hydrophobic Metal-Organic Frameworks: Assessment, Construction, and Diverse Applications.

Metal-organic frameworks (MOFs) have diverse potential applications in catalysis, gas storage, separation, and drug delivery because of their nanoscale periodicity, permanent porosity, channel functionalization, and structural diversity. Despite these promising properties, the inherent structural features of even some of the best-performing MOFs make them moisture-sensitive and unstable in aqueous media, limiting their practical usefulness. This problem could be overcome by developing stable hydrophobic MOFs whose chemical composition is tuned to ensure that their metal-ligand bonds persist even in the presence of moisture and water. However, the design and fabrication of such hydrophobic MOFs pose a significant challenge. Reported syntheses of hydrophobic MOFs are critically summarized, highlighting issues relating to their design, characterization, and practical use. First, wetting of hydrophobic materials is introduced and the four main strategies for synthesizing hydrophobic MOFs are discussed. Afterward, critical challenges in quantifying the wettability of these hydrophobic porous surfaces and solutions to these challenges are discussed. Finally, the reported uses of hydrophobic MOFs in practical applications such as hydrocarbon storage/separation and their use in separating oil spills from water are summarized. Finally, the state of the art is summarized and promising future developments of hydrophobic MOFs are highlighted.

Hydrophobic Metal-Organic Frameworks.

Potential of metal–organic frameworks for adsorptive separation of industrially and environmentally relevant liquid mixtures

Sponge-based materials have recently gained much attention in the field of oil/water separation due to their easy fabrication, recyclability, environmental friendliness, and low cost Commercial sp

Surface Engineering Materials of Superhydrophobic Sponges for Oil/Water Separation: A Review

We demonstrate a new de novo synthetic methodology to achieve high-temperature-stable compelled composite superhydrophobic porous coordination polymers (PCPs). These new PCPs were achieved based on coordination capabilities of first-row transition metal ions such as Co2+, Ni2+, and Zn2+. The obtained composite PCPs containing a [Zn2M2O]6+ (M = Co or Ni) bimetallic cluster core with open metal sites (OMSs) exhibited distinct isosteric heats of adsorption and surface areas due to the difference in their open metal Lewis acidic sites of solvent-free state. Additionally, these composite PCPs exhibit remarkable superhydrophobic properties with contact angles of 159.3° and 160.8° respectively for Zn–Co and Zn–Ni analogues. This superhydrophobic surface survives even at high temperature for longer time periods. As projected, these new composite PCPs exhibit better surface area and heats of adsorption compared to the PESD-1 (Zn) analogue due to a larger number of OMSs. Moreover, they display selective adsorption ...

Temperature-Stable Compelled Composite Superhydrophobic Porous Coordination Polymers Achieved via an Unattainable de Novo Synthetic Method

We achieved a dense I1O3 hybrid superhydrophobic porous coordination polymer (PCP), [Pb(H-BTMB)(DMF)] (1), by solvothermal methods. The single-crystal XRD structure of 1 indicated that it has a three-dimensional M–L–M framework with one-dimensional M–O–M connectivity leading to an I1O3 network. The new PCP obtained exhibited open metal sites (OMSs) by losing a coordinated DMF molecule. The degassed phase displayed selective adsorption of CO2 gas over N2, C2H6, and C2H4 gases. Additionally, it has a superhydrophobic surface with a contact angle of 156.4° at room temperature and it is stable even at 90 °C, displaying a contact angle of 135.3°.

A Dense I1O3 Hybrid Superhydrophobic Network, Pb(H-BTMB), Exhibits Selectivity toward CO2 Gas Sorption

Synthesis and Antibacterial Activity Studies of 8,9‐Dihydro [7h] Benzo 1,2,4‐Oxadiazoles and its Coumarin Derivatives

Investigations of Donor–Acceptor Interactions in 1,3,5-Tris-(3-Methoxy & 3-Methyl Carboxy) Phenyl Ethynyl Benzene Derivatives Using Experimental and DFT Study

We prepared two new superhydrophobic functionalized coordination polymers (SFCPs) [Zn4(OH)2(BTMB)2(4,4'-Bipy)2]∞ ⊃ solvent, 1, and [Cd4(OH)2(BTMB)2(4,4'-Bipy)3]∞ ⊃ solvent, 2, by solvothermal methods. For 1, the single-crystal XRD structure revealed that it contains two crystallographically distinct Zn2+ ions with two different types of coordination geometries of 4 and 6, exhibiting a unique superhydrophobic behavior with microporosity. Compound 1 exhibits superhydrophobicity with a contact angle of 155.5° (at 30 °C), which is stable even at high temperatures, whereas for the SFCP 2, all of the Cd2+ ions have only 6-coordination and exhibit a superhydrophobic character at room temperature with a contact angle of 156.7°(at 30 °C). However, surprisingly, this superhydrophobic character is stable only up to 60 °C, above which it is converted to hydrophilic nature, in contrast to the SFCP 1. Moreover, in this study, we also report a selective gas adsorption study of two C2 gases with similar kinetic diameters (∼3.9 Å) of ethylene over ethane.

Jettiboina Suryachandram

Papers

Temperature-Stable Compelled Composite Superhydrophobic Porous Coordination Polymers Achieved via an Unattainable de Novo Synthetic Method

A Dense I1O3 Hybrid Superhydrophobic Network, Pb(H-BTMB), Exhibits Selectivity toward CO2 Gas Sorption

Synthesis and Antibacterial Activity Studies of 8,9‐Dihydro [7h] Benzo 1,2,4‐Oxadiazoles and its Coumarin Derivatives

Investigations of Donor–Acceptor Interactions in 1,3,5-Tris-(3-Methoxy & 3-Methyl Carboxy) Phenyl Ethynyl Benzene Derivatives Using Experimental and DFT Study

Temperature-Dependent Superhydrophobic Functionalized Coordination Polymers (SFCPs) for Selective Adsorption of C2H4 over C2H6.