Adsorption on Mesoporous Metal–Organic Frameworks in Solution: Aromatic and Heterocyclic Compounds

Abstract

Adsorption and desorption play major roles in separations, purification of water, waste streams, liquid fuels, catalysis, biomedicine and chromatography. Mesoporous metal-organic frameworks (MOFs) with pore sizes 2-50 nm are particularly suitable for adsorption of organic compounds in solution. Tens of thousands of aromatic and heterocyclic compounds are major components of liquid fuels, feedstock for industrial synthesis, solvents, dyestuffs, agricultural chemicals, medicinal drugs, food additives, and so forth. This Review provides a systematization and analysis of studies on adsorption/desorption on mesoporous MOFs in solution and their underlying chemical mechanisms. The (in)stability of mesoporous MOFs in water is critically discussed. Adsorption capacity and selectivity are covered for organic dyes, medicinal drugs, major components of liquid fuels, and miscellaneous industrial chemicals. Ionic interactions, Brønsted acid-base interactions, hydrogen bonding, coordination bonding, π-π interactions, and non-specific interactions are covered amongst adsorption mechanisms. The effects of post-synthetic modifications of mesoporous MOFs on their stability, adsorption capacity, selectivity, and mechanisms of adsorption and desorption are analyzed. To encourage research in this quickly growing field, we identify "niches" for which no application-oriented and/or mechanistic studies were reported. Perspectives and limitations of a wide use of mesoporous MOFs as industrial sorbents are discussed.

Mesoporous Metal–Organic Frameworks: Synthetic Strategies and Emerging Applications

“…The mechanisms for MOFs' adsorption of hazardous materials can be divided into bonding with coordinatively unsaturated sites, acid–base interaction, formation of π‐complex formation, hydrogen bonding, emergence of breathing properties, electrostatic interaction, and so on . Mesoporous MOFs provide much more intriguing opportunities in adsorptive removal of hazardous materials such as aromatic and heterocyclic compounds from solution due to their highly tunable properties.…”

Phenols to Pores to Adsorption. A Potential Route Towards New Methods for Extracting Value From Shale Oil Side Stream

“…A possible route from recorcinols to the MOF linkers is depicted in Figure 1. The Kolbe-Schmitt reaction of 5-MR leads to carboxylation of resorcinol [3][4][5] and subsequent aerobic oxidation to terephthalic acid derivative [6,7]. Carboxylation could be performed also by biochemical means [8,9].…”

MOF the beaten track: unusual structures and uncommon applications of metal–organic frameworks

“…Within the MOF literature, the most commonly described potential applications of these materials are based on their impressive gas storage and sorption properties. Exploration into their capabilities is rapidly expanding, with an increasing number of reviews in areas which describe different aspects of MOFs such as: flexibility [ 1 , 2 ], guest adsorption [ 3 ], stimuli-response [ 4 ], hybridity [ 5 ], photoresponse [ 6 , 7 ], catalysis [ 8 ], sensing [ 9 ], polymerisation vessels [ 10 ], mechanochromic luminescent properties [ 11 ], applications of nanoscalability [ 12 ], use in batteries and supercapacitors [ 13 ], uses as nanomedicine platforms [ 14 ], defects and defect engineering [ 15 , 16 ], computation prediction [ 17 ], surface chemistry [ 18 ] and manipulation into gels [ 19 ]. In this review, we have selected metal–organic frameworks and MOF applications that are outside their traditional and well-reviewed areas, but which further demonstrate the enormously broad potential of this class of materials.…”