Title : Synthetic and industrial jarosites and their application in tissue engineering
Abstract:
Jarosite formation is due to the weathering of sulphide ores that in many cases contain precious metals like silver and gold, being these compounds a source of such metals. Frequently, this formation process occurs in acid-sulphate soils where acidic environments are present. These compounds, joint with beudantite and alunite are part of a great family of mineral species called alunites, in which the general formula is AB3(SO4)2(OH)6, where A is the alkaline site that can be occupied by H3O, Na, Rb, Ag, K, NH4, ½Pb or ½Hg, and B can be Al(III), Cu(II), or Fe(III). According the aforementioned, in metallurgical processes where Fe is a problem, the natural formation of jarosites was reproduced for Fe elimination from leaching liquors prior electrowinning stage, like is the case of the zinc recovery. In this way, the jarosite type-compound can be synthesized in laboratory to evaluate its kinetic formation, reactivity, metals incorporation and the ability of recovery by leaching processes the precious metals contained in these compounds. During many years, the syntheses of these compounds was carried out at high temperatures (95 °C) and long times of reaction (up to 24 hours), which represented high costs if this process could be applied industrially for silver recovery. However, the synthesis process was improved decreasing both, temperature and time (60-70 °C and 3 hours), reaching the precipitation of micro particles of jarosite of sizes varying from 0.2 to 1 mm and spherical and ehudreal morphologies. Recently, the synthesis of these compound are related to some novel applications, like their use as cathodes and/or anodes in Li-ion batteries. But in this case, this material synthesized according the novel parameters aforementioned, was evaluated using cytotoxic assays to determine its possible application as biomaterial. In this work, the synthesis of jarosite was done using Ca, Mg an Sr as doping elements that can also give an additional improvement during its behaviour as biomaterial during bone regeneration. The main results obtained, are that after 10 days the cell proliferation was good, concluding that these synthetic compounds are viable as a biomaterial, due to their non-toxic property. On the other hand, these jarosites show osteoinduction when added to the swine dental pulp stem cell and for this reason, can be used for orthodontic purposes. For this reason, these compound were used for the elaboration of scaffolds, which also were evaluated confirming its non-toxic behaviour and the possibility to be used in experiments in vivo for the bone regeneration, which is in course. Finally, the same cytotoxic assays were done on the jarosites precipitated in the zinc industry, finding better results and giving a future application to these industrial waste, proposing that this residue considered hazardous, could be used in tissue engineering for bone regeneration.
Audience Take Away Notes:
- In this work, authors were working in the synthesis of jarosite type-compound during more than 15 years, trying to find new innovation to be applicable to the zinc industry. However, with the modification of the synthesis parameters could be find smaller and rounded particles, which were evaluated in cytotoxic assays, finding that these compounds are able to be used in the elaboration of scaffold for tissue engineering for in vivo experiments for bone regeneration
- We think that the findings could be used in environmental remediation. The aforementioned is because in the zinc industry this type of compounds are precipitated for Fe elimination from leaching solutions, generation so a great amount of these residues that are considered contaminant and hazardous
- Yes, because the industrial compounds that are considered hazardous, had also a good response during cytotoxic assays, so these results could give added value to an industrial waste
