| 摘要 |
<p>PURPOSE:To obtain a freshness preserver for fruits and vegetables having excellent freshness preservation effect and antimicrobial activity by rendering thermal oxidation history to a porous material mainly composed of silica-alumina mixture. CONSTITUTION:Silica gel and alumina gel are mixed by wet kneading or the like to prepare a silica-alumina mixture. The mixture is fired in the presence of air at about 800 to 1,200 deg.C to give thermal oxidation history. More economically, the waste silica-alumina catalyst used in the catalytic decomposition of heavy oil is treated with thermal oxidation to give the thermal oxidation history whereby the powdery or granular preserver is obtained. When the waste silica-alumina catalyst is used, the catalytic effect of the heavy metal oxides in the catalyst shows microbicidal effect to addition to the enhanced freshness preservation effect.</p> |
