Preparation and analysis of melamine and melamine-silica as clarifying agents of waste lubricating oil

Abstract Melamine is a key compound used as a clarifying agent for waste lubricating oil primarily due to its excellent adsorbent properties. Moreover, considerable interest exists for the further modification of melamine in order to provide a remediation agent with improved clarification capacity. In this study, hexamethylolmelamine was prepared using a solution of formaldehyde, which provided an agent capable of incorporation into a silicate polymer framework. Subsequently, the resultant monomer was added to a solution of silicate to produce the melamine-silica polymer. The melamine and melamine-silica polymer were characterized using the techniques of XRD, FTIR, SSA and thermal analysis to confirm structural and morphological characteristics. These characterizations indicated that the increase in the surface area of the 0.315 m2/g to melamine to 26.71 m2/g of melamine-silica suggests the effective introduction of silanols groups to hexamethylolmelamine and, therefore, corresponds to thehigh performance in relation to melamine as clarifying of waste lubricant oil.

摘要 三聚氰胺（Melamine）凭借优异的吸附性能，是制备废润滑油澄清剂的关键原料。当前，为开发具备更优澄清能力的修复剂，对三聚氰胺进行改性的研究受到广泛关注。本研究以甲醛溶液为原料合成六羟甲基三聚氰胺（hexamethylolmelamine），该产物可接入硅酸盐聚合物骨架。随后将所得单体加入硅酸盐溶液中，制得三聚氰胺-二氧化硅聚合物（melamine-silica polymer）。采用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、比表面积分析（SSA）及热分析技术对三聚氰胺与三聚氰胺-二氧化硅聚合物进行表征，以验证其结构与形貌特征。表征结果显示，三聚氰胺的比表面积从0.315 m²/g提升至三聚氰胺-二氧化硅聚合物的26.71 m²/g，这表明硅羟基基团已成功接入六羟甲基三聚氰胺分子中，因此该聚合物作为废润滑油澄清剂的性能优于纯三聚氰胺。