Preparation Of Copper Inorganic Antimicrobial Materials And Development Of Antibacterial Ceramics

S.aureus,E.coli and other pathogenic bacteria endanger people’s health,and these pathogenic bacteria are very easy to breed and grow in cool,wet ceramic products（such as sinks,toilets,bathtubs and walls）,seriously affecting people’s lives.Therefore,it is of practical importance to develop an antimicrobial material that can be applied to ceramic products with safety and efficiency in order to prevent the harm caused by disease-causing microorganisms.In this paper,natural oxygen-containing minerals（such as silicate minerals,carbonate minerals）as the carrier,anhydrous copper sulfate as copper salt,using the liquid phase method to prepare a variety of copper inorganic antibacterial materials,and then using this kind of copper inorganic antibacterial materials to prepare antibacterial ceramics.The microscopic crystal structure,composition,morphology and antimicrobial properties of the produced copper-based composite antimicrobial materials and antimicrobial ceramics were analyzed and studied by using advanced testing methods such as XRD,SEM,XPS,UV-vis and colony plate counting.The following findings were obtained in this paper:（1）Four clays of 1:1 type layered silicates（kaolinite and erosite）and 2:1 type layered silicates（montmorillonite and talc）were selected as carriers and anhydrous copper sulfate was used as the copper source to prepare and obtain copper-based composite antimicrobial materials,respectively.The XRD results showed that the four copper-based composite antimicrobial materials basically maintained the crystal structures of the original silicates after the loading of copper ions.The ultraviolet spectrophotometry results show that the Cupric ion carrying capacity of 2:1phyllosilicate clay is much higher than that of 1:1 phyllosilicate clay,which is attributed to:the van der Waal bond between 2:1 phyllosilicate layers is weak,which can exchange higher cations.Antibacterial tests showed that the copper-based composite antibacterial material（TCu-1）prepared from talc had the best antibacterial rate against S.aureus and E.coli compared to other silicate materials,with a minimum bactericidal concentration（MBC）of 2.5 mg/ml for E.coli and 3.5 mg/ml for S.aureus.The antimicrobial test after high-temperature calcination showed that all four copper inorganic antimicrobial materials had<70%antimicrobial rate after high-temperature calcination（>800°C）,and the antimicrobial performance decreased significantly,however,the TCu-1 copper inorganic antimicrobial material had>90%antimicrobial rate after calcination at 600°C,and showed better stability at medium and high temperatures.（2）In order to further improve the high-temperature stability of copper inorganic antibacterial materials,talc was selected as the carrier,calcite was added as the adsorbent,and anhydrous copper sulfate was used as the copper source to prepare copper inorganic antibacterial materials containing copper in talc/calcite by liquid phase method.The results of antibacterial test show that when the m_{mixture of talc and calcite}:m_{anhydrous copper sulfat}e=7:3（the mass ratio of talc to calcite=1:1）,the prepared HCCu-50copper inorganic antibacterial material has strong high-temperature stability and antibacterial performance.The XRD and SEM results showed that the effective antimicrobial substance generated was Cu₄SO₄（OH）₆uniformly distributed on the surface of talc/calcite;After calcined at 1000°C,Cu₄SO₄（OH）₆was transformed into Ca₂Cu O₃with better antibacterial performance.It is beneficial to provide a foundation for the later preparation of antibacterial ceramics.（3）Selecting HCCu-50 copper inorganic antibacterial material as antibacterial agent,and adding it into the transparent glaze at low temperature,the antibacterial ceramics with lasting antibacterial were prepared at 1200°C.The analysis of the XPS results shows that there are two chemical valence states of Cu elements in the glaze layer,0-valent and 2-valent,respectively.The results of antimicrobial test,SEM,contact angle meter and micro hardness tester show that with the increase of antimicrobial agent doping,the micro hardness and contact angle to water show a trend of first decrease and then increase,and the antimicrobial performance,glaze pore size and number show a trend of first increase and then decrease.Combining the above experimental results,the best overall performance of the experimentally obtained antimicrobial ceramics was obtained when the antimicrobial agent doping amount was 2%.The antimicrobial ceramics obtained by this method showed excellent antimicrobial effect even after 6 months of storage.