Polymer-assisted modification of metal-organic framework MIL-96 (Al): influence of HPAM concentration on particle size, crystal morphology and removal of harmful environmental pollutant PFOA.
Mohd Azmi, Luqman Hakim; Williams, Daryl R; LADEWIG, Bradley Paul
Adsorption; Crystal morphology; HPAM; Metal-organic frameworks; Particle size; Perfluorooctanoic acid; Acrylic Resins; Aluminum; Caprylates; Charcoal; Fluorocarbons; Metal-Organic Frameworks; perfluorooctanoic acid; polyacrylamide; Water Pollutants, Chemical; Acrylic Resins/chemistry; Charcoal/chemistry; Particle Size; Solubility; Surface Properties; Aluminum/chemistry; Caprylates/analysis; Fluorocarbons/analysis; Metal-Organic Frameworks/chemistry; Water Pollutants, Chemical/analysis; Water Purification/methods; Adsorption capacities; Crystal morphologies; Environmental pollutants; High ionic strength; Hydrolyzed polyacrylamides; Larger particle sizes; Watersoluble polymers; Lysergic Acid Diethylamide; Water Purification; Environmental Engineering; Environmental Chemistry; Chemistry (all); Pollution; Health, Toxicology and Mutagenesis; General Medicine; General Chemistry; Public Health, Environmental and Occupational Health
Abstract :
[en] A new synthesis method was developed to prepare an aluminum-based metal organic framework (MIL-96) with a larger particle size and different crystal habits. A low cost and water-soluble polymer, hydrolyzed polyacrylamide (HPAM), was added in varying quantities into the synthesis reaction to achieve >200% particle size enlargement with controlled crystal morphology. The modified adsorbent, MIL-96-RHPAM2, was systematically characterized by SEM, XRD, FTIR, BET and TGA-MS. Using activated carbon (AC) as a reference adsorbent, the effectiveness of MIL-96-RHPAM2 for perfluorooctanoic acid (PFOA) removal from water was examined. The study confirms stable morphology of hydrated MIL-96-RHPAM2 particles as well as a superior PFOA adsorption capacity (340 mg/g) despite its lower surface area, relative to standard MIL-96. MIL-96-RHPAM2 suffers from slow adsorption kinetics as the modification significantly blocks pore access. The strong adsorption of PFOA by MIL-96-RHPAM2 was associated with the formation of electrostatic bonds between the anionic carboxylate of PFOA and the amine functionality present in the HPAM backbone. Thus, the strongly held PFOA molecules in the pores of MIL-96-RHPAM2 were not easily desorbed even after eluted with a high ionic strength solvent (500 mM NaCl). Nevertheless, this simple HPAM addition strategy can still chart promising pathways to impart judicious control over adsorbent particle size and crystal shapes while the introduction of amine functionality onto the surface chemistry is simultaneously useful for enhanced PFOA removal from contaminated aqueous systems.
Disciplines :
Chemical engineering
Author, co-author :
Mohd Azmi, Luqman Hakim ; Barrer Centre, Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ, London, United Kingdom, Grantham Institute - Climate Change and the Environment, Imperial College London, South Kensington Campus, SW7 2AZ, London, United Kingdom, Surfaces and Particle Engineering Laboratory (SPEL), Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ, London, United Kingdom
Williams, Daryl R; Surfaces and Particle Engineering Laboratory (SPEL), Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ, London, United Kingdom
LADEWIG, Bradley Paul ; University of Luxembourg > Faculty of Science, Technology and Medicine (FSTM) > Department of Engineering (DoE) ; Barrer Centre, Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ, London, United Kingdom, Institute for Micro Process Engineering (IMVT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany. Electronic address: bradley.ladewig@kit.edu
External co-authors :
yes
Language :
English
Title :
Polymer-assisted modification of metal-organic framework MIL-96 (Al): influence of HPAM concentration on particle size, crystal morphology and removal of harmful environmental pollutant PFOA.
Luqman Hakim Mohd Azmi gratefully acknowledges the financial support provided by the sovereign wealth fund of Malaysian Government, Yayasan Khazanah for his PhD studies. The authors also thank Prof. Paul D. Lickiss, Dr. Pavani Cherukupally, Elwin Hunter-Sellars, Dr. Shanxue Jiang and Tingwu Liu for useful discussion on material design and characterization.
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