Functionalized Metal‐Organic Frameworks for Hg(II) and Cd(II) Capture: Progresses and Challenges

Abstract

Mercury and cadmium are deemed to be the most harmful heavy metal ions for elimination due to their persistent bio‐accumulative and bio‐expanding toxic effects. Although many technologies have been developed for capturing Hg(II) and Cd(II) ions from aqueous solution, developing efficient and practical capature technology remains a big challenge. Metal‐organic frameworks (MOFs) have been considered as the most promising adsorbents for Hg(II) and Cd(II) removal due to their high porosity and easy functionalization, and various of MOF‐based adsorbents based on different synthetic strategies have been prepared and studied. In this article, the progresses of MOF‐based absorbents for Hg(II) and Cd(II) capture are described according to the synthetic strategies and the types of functional groups, and the comparison and practical analysis of various adsorbents are also presented.

Recognition and Sequestration of Toxic Inorganic Water Pollutants with Hydrolytically Stable Metal‐Organic Frameworks

“…exhibit suboptimal performance due to their inherent restrictions, e. g. lack of tailorability, lower surface area, slower kinetics etc [24–26] . To this end, adsorption based techniques are proven to be potent alternative towards such pollutant remediation on account of it's simplicity, energy as well as cost considerations [27–29] …”

Metal–Organic Frameworks for CO2 Separation from Flue and Biogas Mixtures

“…[ 87–101 ] The advantages of MOFs arose from their superiority in surface modification, [ 102–105 ] effective pore modulation [ 106–110 ] and low‐ to moderate‐temperature thermal activation, [ 111–114 ] which kept it upper hand for practical deployment toward this challenging separation direction over other conventional previously developed porous materials. These advantages of MOFs sparked interest in a vast range of potential applications involving gas storage and separation, [ 10,115–124 ] proton conductivity, [ 2,125–135 ] sensing, [ 136–142 ] luminescence, [ 143,144 ] heterogeneous catalysis, [ 145–152 ] and so on. [ 153–166 ] Specifically, the investigation of MOFs toward flue gas (15% CO 2 and 85% N 2 ) and biogas (50% CO 2 and 50% CH 4 ) mixture separation has overgrown in recent years ( Figure ) over other potential application domains, and tremendous efforts have already been devoted to the development of MOFs to comprehend a better trade‐off between high CO 2 sorption capacity and separation selectivity.…”

Efficient and Selective Removal of Hg(II) from Aqueous Solution by a Highly Stable Amino Isonicotinic-Based Coordination Polymer

“…Hg 2+ is a highly toxic pollutant that is widely distributed and nondegradable in water systems. When absorbed by animals, it is distributed throughout the body with the blood flow, poisoning different body parts. − Researchers have developed many removal technologies and materials to alleviate the environmental problems caused by pollutants such as Hg 2+ . − However, although the current water-treatment technologies can eliminate harmful pollutants from wastewater, their effectiveness is limited by inevitable drawbacks. For example, biological treatment is cost-effective but its pollutant-removal efficiency is below the necessary limit level and the process generates a large amount of sludge. , The adsorption method achieves lower energy consumption, higher removal efficiency, and more complete separation than biological treatments, which are advantaged by simple operation, low cost, environmental friendliness, and recyclability.…”