Water is essential in all aspects of life, being the defining characteristic of our planet and even our body. Regrettably, water pollution is increasingly becoming a challenge due to novel anthropogenic pollutants. Of particular concern are emerging organic contaminants (EOCs), the term used not only to cover newly developed compounds but also compounds newly discovered as contaminants in the environment. Aside from anthropogenic contamination, higher temperature and more extreme and less predictable weather conditions are projected to affect water availability and distribution. Therefore, wastewater treatment has to become a valuable water resource and its reuse is an important issue that must be carried out efficiently. Among the novel technologies considered in water remediation processes, metal-organic frameworks (MOFs) are regarded as promising materials for the elimination of EOCs since they present many properties that commend them in water treatment: large surface area, easy functionalizable cavities, some are stable in water, and synthesized at large scale, etc. This review highlights the advances in the use of MOFs in the elimination (adsorption and/or degradation) of EOCs from water, classifying them by the nature of the contaminant.

Metal-Organic Frameworks for the Removal of Emerging Organic Contaminants in Water.

Adsorptive removal of dyes from wastewater using a metal-organic framework: A review

Metal–organic frameworks (MOFs), a versatile class of porous materials that exhibit high specific surface areas, controllable structures, and tunable pores, have been identified as a promising plat

Recent electrochemical applications of metal-organic framework- based materials

Light-responsive materials with high adsorption capacity and sunlight-triggered regenerability are highly desired for their low-cost and environmentally friendly industrial separation processes. Here we report a poly(spiropyran acrylate) (PSP) functionalized metal–organic framework (MOF) as a sunlight-regenerable ion adsorbent for sustainable water desalination. Under dark conditions, the zwitterionic isomer quickly adsorbs multiple cations and anions from water within 30 minutes, with high ion adsorption loadings of up to 2.88 mmol g−1 of NaCl. With sunlight illumination, the neutral isomer rapidly releases these adsorbed salts within 4 minutes. Single-column desalination experiments demonstrated that PSP–MOF works efficiently for water desalination. A freshwater yield of 139.5 l kg−1 d−1 and a low energy consumption of 0.11 Wh l−1 would be reached for desalinating 2,233 ppm synthetic brackish water. Importantly, this adsorbent shows excellent stability and cycling performance. This work opens up a new direction for designing stimuli-responsive materials for energy-efficient and sustainable desalination and water purification. Light-responsive smart materials hold promise for a solution to water desalination. Here the authors report an adsorbent based on a metal–organic framework that quickly adsorbs multiple ions from water in the dark, followed by release of these salts on exposure to sunlight.

A sunlight-responsive metal–organic framework system for sustainable water desalination

Pristine metal-organic frameworks (MOFs) have received much attention in recent years due to their high specific surface areas, large porosity, excellent pore size distributions, flexible structure, and remarkable catalytic properties. The design of functional MOFs that can function as efficient HER and OER catalysts is significant in solving the energy crisis but remains a big challenge. Tri-metallic metal-organic frameworks show a good application prospect in water oxidation. In this review, we are going to focus on the latest progress and future trends in the development of pristine trimetallic MOFs with respect to the OER. The synergistic effect between multi-metal active sites is effective at improving the intrinsic activity of MOFs toward the OER. By summarizing the synthesis method of tri-metallic MOFs and observing their performance toward the oxygen evolution reaction, we hope that this review will trigger new developments in coordination chemistry, electrochemistry, nanomaterials and energy materials.

Recent advances in pristine tri-metallic metal–organic frameworks toward the oxygen evolution reaction

The role of breathing behavior in hydrated and dehydrated forms of MIL-53(Fe) is investigated here. The material can be used as an efficient electrocatalyst and photocatalyst for a hydrogen evolution reaction (HER) in an alkaline medium and the same was further tested for the degradation of organic pollutants. The as-synthesized MIL-53(Fe)/hydrated and dehydrated forms were characterized by different analytical techniques to study their structure, morphology, surface analysis, thermal, physical and chemical properties. The breathing behavior of the hydrated and dehydrated forms of MIL-53(Fe) was studied through BET surface analysis. Our results show a low onset potential (−0.155 V and −0.175 V), Tafel slope (71.6 mV per decade, 88.7 mV per decade) and a large exchange current density (1.6 × 10−4 mA cm−2 and 2.5 × 10−4 mA cm−2). Hydrated and dehydrated MIL-53(Fe) degraded an RhB dye solution within 30 minutes thus proving their efficiency as efficient photocatalysts.

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Krishna Chandar

Papers

Role of MIL-53(Fe)/hydrated–dehydrated MOF catalyst for electrochemical hydrogen evolution reaction (HER) in alkaline medium and photocatalysis