Evaluation Of Antibacterial Activity And Environmental Effect Of Ocean Polymetallic Nodules And Cobalt-rich Crusts Residue

The paper is part of "the Research of Application technology of Ocean PolymetallicNodules and Cobalt-rich Crusts Leaching Residue Functional Filling", the Tenth-FiveProject (DY105-2-04-14) managed by China Ocean Mineral Resources R&D andAssociation(COMRA), which emphasises on evaluating the antibacterial activity andenvironmental effect of residue. After the project team successfully developed the residuewaterborne anticorrosion coating and based on the result of the experiment researches onresidue used as concrete additives, the research evaluated antibacterial activity andenvironmental effect of residue,residue waterborne anticorrosion coating and residueconcrete. Antibacterial circle method , antibacterial rate method and mildew killing activityexperiment method are applied to evaluate the antibacterial capability.Air purifyingcapability is investigated by 24h purifying rate on mercaptan and benzene. After themeasurement of the increased concentration of negative ion produced by residue, theantibacterial circle experiment of the soluble substance in residue water, the ores of oceanpolymetallic nodules and cobalt-rich crusts,combined with the chemicalcomposition,structure and physics property analysis of the residue, the mechanism of theantibacterial and air purifying activity is studied in the research.The paper shows that the residue has excellent antibacterial properties.The antibacterialcircle diameter of the ocean polymetallic nodules residue on E.coli and S.aureusrespectively reaches 16mm and 18mm, and the ocean cobalt-rich crusts residue 18mm and17mm.Moreover,the circle has not been apparently chaged after 28 days, only a fewbacterium regrow on the circle. The 24h antibacterial rate of Residue waterborneanticorrosion coating on E.coli and S.aureus reaches over 90%,meeting the antibacterialproducts standard in JC/T 897-2002.The antimildew level is zero,which means that thecoating has a strong resister capability on mildew according to JC/T 2591-2002.The 24hpurifying rate of the coating on ammonia is more than 30% ,and 20% on benzene. The24h antibacterial rate of the residue concrete on E.coli and S.aureus is between 60% and80%,and the purifying capability on ammonia and benzene is a bit low in 24 h.The paper shows that the antibacterial and air purifying activity of the residue is due tonegative ions.In the residue ,the rare earth elements in a state of ion are absorbed on thesurface of nano-particulates,which can activate the oxygen and the water in the air ,andproduce negative ions.And physical absorption happens too when the residue is purifyingammonia and benzene.