Once precious metals are sorbed on to the biosorbent, to recover the metal back, is it advisable to go for desorption by leaching using acids, alkalis, chelating agents or solvent extraction. These do not completely destroy the sorbent but may destroy their active binding sites. So in the subsequent sorption cycle the process may not be as efficient as in the previous cycle. Pyrolysis or incineration on the other hand will destroy the sorbent but the precious metal will be well recovered. If the cost of the recovered precious metal is >>> the cost of production of the biosorbent, is it right to go for pyrolysis or incineration rather than description by leaching or solvent extraction.
Good idea Kruti, to reuse and recovery of precious and critical metals must be developed To meet the global challenges of elemental sustainability a holistic approach to the extraction,. Bio sorption is a key technology for the benign recovery of diffuse elements from liquid effluents and hydrometallurgy processes. There is the opportunity to go beyond the remediation of heavy metals and pollutants, by utilising bio sorption within a circular economy approach for the cycling of precious and critical metals in higher-value applications. This review provides an overview of the current research in the area of critical and precious metals recovery using bio sorption, its application to real-life wastes and the potential uses for these metal-loaded materials for catalysis or functional material. This is good idea, cost doesn’t matter remediation of heavy metals and pollutants is primary object for eco-friendly approach.
According to the dependence on the cell's metabolism, biosorption mechanisms can be divided into:
Metabolism dependent and
Non -metabolism dependent.
According to the location where the metal removed from solution is found, biosorption can be classified as
Extra cellular accumulation/ precipitation
Cell surface sorption/ precipitation and
Intracellular accumulation.
regards,
Prem Baboo
https://www.researchgate.net/profile/Helmut_Brandl3
Prem Baboo, I have to disappoint you, but most of the researchers do not consider removal of metals (or any other adsorbates) by living organisms as "biosorption", but "bioaccumulation". And it would be nice if you could give us the title of the review you were talking about.
Hi again, you come up with very interesting and attention-claiming questions. i am not really a specialist, although I dabble in this area trying to help in what I can one of our students. I feel however that the question is too generic to warrant a single, mind-clearing answer. From my point of view, the answer should be a number of additional questions, such as: how badly would the substrate be damaged by the recovery process? what is the cost of the substrate? what would the cost be, to fix the damage? comparative cost of recovery from the ashes and from the alternative recovery process? additionally: any problem with fumes and fly ashes? (I might have forgotten some, but these seem enough at least for the moment).
Now, once you have an answer to all these, I am fairly sure that you have also an answer to your original question.
I shall follow with interest, Thank you for your mind-stretching questions (I envy your supervisor, I love it when students put me to think, it makes me feel that I am not really wasting whatever little time I have left). cheers
The biosorbents have some limitations although a lot of work is done and going on but comparatively few patents are available that means that there are some problems either the field is not explored or there is a gap?
So far adsorption by living organism is considered it is of course not that much intensively studied as reference Prof. wang review can be studied (Biosorption of heavy metals by Saccharomyces cerevisiae A review).
Any way this is a good and long discussion and should be continued.
In biosorption the sorbent used in most of the cases is low cost and if its sorption capacity is appreciable the ideal way should be incineration because they are normally not reusable.
Hola Kruti.
Depende, si es adsorción fisica el bioadsorbente no va a ser destruido (como el caso del GAC); si la adsorción es quimica el bioadsorbente se va destruir y en ese caso podria ser bueno la incineración o pyrolisis, si lo costos de operación son mucho menores que el precio del metal precioso.
Hi everybody, I guess I will take up the role of interpreter again: here it goes
"it depends, if you are dealing with physical adsorption, the bioabsorbent will not be destroyed, as is the case with GAC (my observation, I guess Edwilde means biosorbent or bioadsorbent). If it is chemical the biosorbent will be destroyed and in this case ashing or pyrolysis could be better, if operayting costs are lower than the price of the precious metal.
Hasta la vista
Agreed Artis Robalds.
Thank you Domenico Voltolina for your appreciation, encouragement and translation. The queries you put forward are definitely worth a good discussion and important for practical application.
Thank you Edwilde Yoplac for your feedback. Suggestion well taken.
Right, pyrolysis will leave a residue which will have to be didposed of if recovery of metal is the ultimate aim of the process. Conceivably, it will also minimize the problem of fly ashes mentioned by Pushpa. Of course, decision on the process is another one of the questions I was referring to in a previous answer, which was rather a series of questions (namely, if we do not know the nature of the sorbent and of the sustrate we might have problems in identifying a possible residue)
Hope this review might be useful. http://www.sciencedirect.com/science/article/pii/S0001868616302184
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