High Yield Collection of Uranium From Seawater Using Graphene Oxide Functionalized with Protein.

[NNadir]

Last edited Sat Apr 15, 2017, 08:29 AM - Edit history (1)

One of my favorite scientific journals is Industrial & Engineering Chemistry Research where (in a predecessor version) one of the most cited papers of all time (8717 citations as of this writing) was published, this one: A New Two-Constant Equation of State

(A beautiful and industrially extremely important equation it is...)

It's been many years since I missed an issue of this journal, which is always fun since it's very broad and one never knows what's going to turn up there, and reading it one feels like a kid in a candy shop as they say, or a kid in a toy store.

A recent issue contained a special treat at the interface of materials science - a career my youngest son will be pursuing in a very wonderful engineering university - proteomics which has been an important - but not necessarily the major - part of my career, and the chemistry of uranium, which is one of my favorite elements whose properties I study non-professionally, since it represents the last, best hope of the human race to save itself from itself.

The paper was written by Chinese scientists and a link to it is here: Bovine Serum Albumin-Coated Graphene Oxide for Effective Adsorption of Uranium(VI) from Aqueous Solutions

An excerpt from the introductory text from the paper:

Currently, numerous researchers are focusing on the availability and cost of U^VI to fuel nuclear reactors because conventional land-based uranium sources may become depleted by the end of the century.2?4 Therefore, exploitation of alternative uranium sources, such as the extraction of U^VI from seawater, is of great importance and will ensure the long-term availability and development of this nuclear fuel. Extraction of U^VI from seawater embraces organic?inorganic ion exchange, electrodialysis, physical and chemical adsorption, chemical precipitation, and extraction.5?8 Adsorption techniques especially stand out from the aforementioned technologies because of their greater feasibility, efficiency of consumption, simple operation, and facility in removing trace levels of ions.9,10 In these techniques, the design of adsorption materials greatly influences the extraction of U^VI from seawater. Many efficient2D materials based on graphene oxide (GO) have been utilized for adsorption of the radiation element, such as polyaniline?GO,11 GO?polypyrrole,12 GO?dopamine?cysteine,13 GO?amidoxime hydrogel,14 GO?Ni?Al-layered double hydroxide,15 and GO?dopamine.16

It would appear that the Chinese scientists who authored this paper are unimpressed by the dunderhead impressions of professional anti-nukes like, say, those fellows over at the Union of Concerned "Scientists" who imagine that any risk from nuclear energy is vastly more important than the observed risk of dangerous fossil fuel and dangerous biomass combustion waste. Dangerous fossil fuel and biomass waste kills more people than died in World War II from all causes every seven or eight years, like clockwork, seventy million people every decade, not even counting climate related deaths.

This said, the subordinate clause in the first sentence of this excerpt is only true in the case where humanity continues to observe and embrace a "waste" mentality. Converted to plutonium, the uranium already mined, including but not limited to "depleted uranium" coupled with the thorium currently being dumped by the mining enterprises that support the useless wind and electric car industries is sufficient to supply all of the humanity's energy needs - all currently supplied by the dangerous fossil fuel industry as well as the environmentally dubious forms of so called "renewable energy" - for centuries.

I made this point elsewhere: Current World Energy Demand, Ethical World Energy Demand, Depleted Uranium and the Centuries to Come

However, if we look over millennia under the questionable assumption that humanity won't kill itself by embracing highly questionable fantasies, it may be necessary in the far off future to isolate uranium from seawater or natural water supplies in which it is found owing to geology or because of enterprises like fracking which mobilize NORM (Naturally Occurring Radioactive Materials) including (but not limited to) uranium.

The uranium in seawater is inexhaustible even if humanity were to survive on this planet for as long as the sun exists.

I also made this point elsewhere with some reference to the crustal and mantle uranium flux:

Sustaining the Wind Part 3 – Is Uranium Exhaustible?

One of the pleasures of taking my son on college tours as well as accepted student tours has been the opportunities to meet and hear from a number of academic materials scientists and engineers. Some people regard graphene as an academic curiosity that will prove industrially difficult to manufacture, but in at least one department - not the one my son will choose to attend since he had much better offers elsewhere - that holds patents on what is said to be an industrial graphene production processes.

(I haven't looked into the details, so I can't say if these processes are truly viable industrially.)

In the cited paper, graphene oxide is functionalized by bonding a protein to it - bovine serum albumin, obtained from cow's blood. As a vegetarian, I can tell you that it might not be necessary to kill cows to get this stuff, the industrial preparation of pure (or relatively pure) proteins from cultures of genetically modified - everything from E. Coli to Chinese Hamster Ovary - cells is common practice, and is important in the preparation of many modern drugs. Thus, were one to desire to industrialize this chemistry - it won't happen - it is at least feasible, not desirable but feasible to produce this or other similar proteins without requiring cows or other animals or plants.

The process chemistry described in the paper is unattractive from an environmental perspective:

2.2. Synthesis of the Graphene Oxide (GO)?BSA Composites. GO. GO was prepared by a modified Hummer’s method.39 For the reaction, 0.5 g of graphite and 115 mL of H₂SO4 were stirred in an ice bath for 1 h. Then 30 g of KMnO₄ was slowly added, and the reaction temperature was maintained at about 0 °C for 3 h. The solution was transferred to a 50 ± 5°C water bath and stirred for 45 min. Then 400 mL of H₂O was added slowly, followed by stirring for 15 min while the temperature was raised to 50 ± 5 °C. Finally, 300 mL of H₂Oand 360 g of H₂O₂ (5%) were added to the solution with stirring for 15 min. The warm solution was then filtered and washed with H₂O until the pH was 6?7. The final product was dried for 3 days in a vacuum oven.

GO?BSA. A total of 20 mg of GO, 60 mg of BSA, 35 ?L of Py, and EDCI/HOBt/DMAP (molar composition = 1.5:1:0.5)were dissolved in 6 mL of a distilled water/DMF reaction mixture (distilled water/DMF = 4 mL/2 mL) for 5 h at room temperature. Then the solution mixture was washed with amass ratio of ethanol/distilled water = 3/1. Finally, the solution mixture was freeze-dried for 3 days.

In any case there are many metal complexing proteins that are certainly superior to BSA, the transferrins come to mind, and one can imagine designing proteins, or peptides or even other potentially biologically accessible complexing agents (such as porphyrins, the core of both chlorophyll and hemaglobulin) that will do a better job.

But in any case, were we to stop being stupid about "depleted uranium" and decided to use it rather than dump it, the issue would not be relevant for many centuries, during which we might invent far more sustainable chemistry.

Nevertheless, the claimed recovery of uranium from simulated seawater for this process is remarkable, roughly reported as 390 mg per gram. This is orders of magnitude higher than other chemical approaches to doing the same thing, many of which have already been tested on a pilot scale.

Esoteric, probably not practical, but certainly interesting.

Have a nice Friday morning tomorrow.