Synthesis And Performance Studies Of Environmentally Friendly Antibacterial DBDMH/SiO₂ Composite Particles

l,3-dibromine-5,5-dimethylhydantoin (DBDMH) is an antibacterial which has beenwidely used in water treatment including industrial water and recycled cooling water as wellas aquaculture. DBDMH has many advantages such as high efficiency, broad spectrum,environmentally friendly and steady to be used. The efficiency of DBDMH production is 90%with an optimum mol ratio of 1:2:2 of hydantoin: Br2: NaOH.DBDMH/hydrophilicSiO₂Composite articles with different values ofDBDMH/hydrophilic SiO₂ were prepared by adding hydrophilic SiO₂ of different quantitiesto the hydantoin solution. DBDMH/ hydrophobic SiO2 composite particles were synthesizedwith hydrophobic SiO2 substituted for hydrophilic SiO₂. It was also found that the addition ofhydrophilic SiO2 did not affect the production of DBDMH while the addition of hydrophobicSiO₂ weaken the production of DBDMH.The FTIR micrographs of DBDMH/hydrophilicSiO₂ and DBDMH/ hydrophobic SiO₂ composite particles showed that DBDMH and SiO2had formed composite particles different from the mixtures. The Scanning electronicmicrographs (SEM) showed that there were floes at the surface of the hydrophilic SiO2 as aresult of DBDMH adsorption. The difference also existed between the composite and mixtureof DBDMH/hydrophobic SiO₂. The composite particles were without distinct spaces betweeneach other, while there were large inter-particle spaces in the mixture. DBDMHconglomeration decreased in the composite particles.The minimum inhibition concentrations (MIC) of two kinds of composite particles on E.coli and Staphlylococcus.were almost the same of 0.125 mg/ml. The inhibition efficiencies ofthe composite particles were higher than those of DBDMH. Furthermore, the compositeparticles had higher inhibition effects .The results showed DBDMH in composite particles hadhigher dispersability and sustained release activity than that in pure DBDMH.