Purifying Water with Nanofibrous MOF Membranes

Purifying Water with Nanofibrous MOF Membranes

Author: Irene Maluenda

Water contaminated with heavy metals is an important environmental concern, especially due to the metals’ cumulative effect in organisms. Metal-organic frameworks (MOFs) are coordination networks of metal ions or clusters linked using organic ligands. The combined effects of the organic and inorganic moieties allow tuning the size of the pores and provide high surface area to mass ratios while ensuring that the material is chemically and structurally stable.

Dipak Rana and colleagues, University of Ottawa, Canada, have developed an efficient membrane containing MOFs that can efficiently remove Pb2+ and Hg2+ ions by filtration of contaminated water solutions. MOF 808, containing Zr6 clusters, and the Fe-based MOF-F300 were enmeshed in nanofibers of polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF).

The team concluded that the adsorption of the metals was due to a combination of competitive ion exchange, electrostatic interactions, and pore filling of the MOFs. Removal of Hg2+ and Pb2+ was achieved under controlled acid conditions. The experiments demonstrated that the total negative charge of the deprotonated COOH groups at the metal clusters drags the positive metal ions from the surface into the pore cavity. This was shown by a continuous decrease of the pH as the heavy metal ions promoted the release of protons.


 

Comments

  1. Tarun Tapan Roy

    Removal of heavy metal ions (like Hg2+ and Pb2+) from contaminated water with the membrane containing Fe(III) and Zr(IV) based metal-organic frameworks that enmeshed in polyacrylonitrile and polyvinylidene fluoride electro-spun nanofibers have successfully developed by Rana e tal. This filtration technique will be more useful than ion exchange, electrostatic interaction and other traditional methods. So, I have strongly recommended this adsorption technique to publish in daily newspapers to aware public.

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  2. GOVIND SETHIA

    Excellent piece of work from Rana and Matsuura research Group from the University of Ottawa.

    The beauty of the work is the cumulative effect of competitive ion exchange, electrostatic interactions, and pore-filling of the MOFs for the removal of heavy metals. Utilizing different phenomenon and developing a hybrid system is a brilliant approach for the effective water treatment.

    With increasing demand for clean water, no doubt in future clean water is going to be our next oil, and the demand for the easy, energy efficient and economic clean water technologies will only be a solution to fulfil this requirement for the increasing industrialization and world population.

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  3. Sib Sankar Mal

    Excellent piece of work!!!! Hats off to the Prof. Rana and Prof. Matsuura group for discovering this adsorption technique. They have discovered a new class of materials for removal of heavy metals form the contaminated drinking water. It is indeed a brilliant approach for the water treatment. Currently, the whole world is facing the water crisis challenge and this MOF membrane would be the next generation technology without any doubt.

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  4. Arun Guha

    Dr. Rana and his group have done a great work. Their discovery might be use full in textile effluent treatment., because textile effluent contains different types of heavy metals.

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  5. Uttam Das

    An excellent discovery of Nanofibrous MOF Membranes for removing heavy metals by Dipak Rana and Prof. Matsuura group. The group showed that a new class of MOF materials selectively adsorb heavy metal ions (Hg2+ and Pb2+) from the contaminated drinking water. It is an outstanding adsorption technique not only useful in clean water technology but also in other areas i.e., in the textile industry, wastewater treatment, manufacturing industry where the removal of these toxic metal ions remains a huge challenge.

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  6. pankaj kaware

    From the perspective of the world-wide problem of safe drinking water due to contamination of groundwater by leached out heavy metals ions (HMIs), this innovative research is very welcomed. Human body needs some heavy metals like iron (e.g. hemoglobin, cytochrome), zinc (e.g. Zn finger proteins), copper (e.g. Cu proteins), manganese (e.g. Mn-dependent superoxide dismutase), cobalt (e.g. cobalamin, B12), molybdenum (Mo oxo transferase), etc., however, the toxicity increases when present in higher amount, for example exposure to mercuric salt could have toxicological effects on gastrointestinal tract and kidney, lead(II) has been demonstrated to cross blood-brain barrier that effects the central nervous system. The developed metal organic frameworks (MOFs) with nano-fibrous adsorbent has been found to a high absorption capacity of 53.1 mg/g (MOF-808) to 42.6 mg/g (F-300) for Hg+2, and 30.2 mg/g (MOF-808) to 17.2 mg/g (F-300) for Pb+2, respectively. Furthermore, the activated MOF-808 with nano-fibrous adsorbent has also been found to be a high absorption capacity of 43.9 mg/g for Cd+2 and 56.7 mg/g for Zn+2. Therefore, I sincerely believe the research will have a new contribution to the field of abatement of HMIs contamination problem of drinking water.

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  7. Narayan Sinha

    Accessibility of clean water is a basic human right. However, billions of people in the world do not have the access of potable water and they are forced to live by drinking unsafe water which causes them illness and life-threatening diseases. Among others, heavy metal (e.g., lead, mercury, arsenic, etc.) contamination is one of the major areas of water pollution. Therefore, a large number of scientists in all over world are focused on the development of methodologies and technologies for improved water purification systems. Very recently, Dr. Rana and co-workers (University of Ottawa) have reported an efficient method based on nanofibrous MOF material which can remove toxic metal ions like mercury and lead ions from non-drinkable aqueous solution, making it drinkable, clean water. The adsorption quality of the membrane is very high and even after four cycles of adsorption and desorption, still more than 90% adsorption quality of the nanofibrous MOF membrane is retained. I personally think that it a great research work. I strongly recommend Dr. Rana and his group members to use this methodology in the water purification systems and try to commercialize their material.

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  8. Sandipan Dutta

    Interesting work done by the authors is an important addition to technological options to clean contaminated water. Reported regeneration and filtering efficiency self explains its potential. Congratulations to Dr. Rana and the team for excellent work.

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  9. Ritesh Tailor

    Dr. Johnson, Dr. Dipak Rana and his group have a great contribution in developing a quality membrane for the treatment of polluted water. Their discovery of Nanofibrous MOF membrane has opened an excellent approach to deal with heavy metal water pollution. The multiple interactions e.g. ion exchange, electrostatic interactions, pore filling and surface adsorption nature of the membrane has provided an ultra-high adsorption property. The important part of their research is the re-usability of the membrane with adequate capacity for drinkable water treatment which makes it more attractive for commercialization point of view. Authors are still expecting to get improvement over their current innovative discovery. A big congratulation to an amazing talented group. Wish you all the best for future.

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  10. PRABIR KUMAR KULABHUSAN

    Excellent work done by the Dr. Rana and his team for the removal of heavy metal from the drinking water. Safe drinking water is one of the basic necessities for the society. Current commercial method to remove heavy metals tends to be costly, and not efficient enough. The application of nanofibrous MOF membrane has shown a new avenue for removal of toxic heavy metal and make the water drinkable. The technology is in the process of commercialisation and definitely a boon for the society. Congratulations to Dr. Rana and his team and wish you best for future research.

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  11. Emdadul Haque

    Congratulations to Dr Rana and his colleagues for their innovative work and novel technique for the purification of drinking water. This is an excellent technique for removal of toxic heavy metals. The membrane filtration technology with the recycling process is based on combinations of several conventional techniques which provide durability and cost effectiveness. Millions of people around the globe will benefit from this work. Keep it up and best wishes for upbringing the technology to the commercial stage.

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  12. Chandi Pariya

    Metal-organic frameworks (MOFs) have been proved as promising adsorbents because of excellent porosity, designable adsorption sites, and controllable water stability. Dr Rana and his group details the breakthrough discovery of nanofibers MOF membranes for removing heavy metals ions. The adsorption behaviors of the materials and corresponding structure-performance relationships were discussed exclusively for efficient water purification. My sincere congratulations to Dr. Rana and his esteemed research group for award winning applied research. I think it will be very useful if Dr. Rana get more funds to explore more on this excellent research topic. I wish him all the best for his future endeavor.

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