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 m 2 /g to melamine to 26.71 m 2 /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.

Zinc-salt assisted synthesis of three-dimensional oxygen and nitrogen co-doped hierarchical micro-meso porous carbon foam for supercapacitors

“…Calculations revealed that the average crystallite size of these particles is about 13–15 nm. The lack of the characteristic peaks of melamine in the X-ray diffraction pattern of the as prepared foam along with the wide shoulder at about 25° confirm the reaction of melamine with formaldehyde and the formation of amorphous melamine–formaldehyde resin in the as prepared foam 33 – 36 . Decomposition of Zn(NO 3 ) 2 to ZnO particles, by the following chemical reaction, can be accompanied by the formation of carbon foam 32 , 37 :

Figure 1 Structural development of the synthesized foam during thermal treatment ( a ) X-ray diffraction patterns of the synthesized foams, ( b ) Thermal gravimetric analysis results of the prepared foams with 2, 4 and 6 g of Zn(NO 3 ) 2 .6H 2 O, ( c ) Raman Spectra of the carbon foams.

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A novel strontium-based MOF: synthesis, characterization, and promising application in removal of 152+154Eu from active waste

“…Besides, the peak of N–H sp 2 of melamine at 3418 cm −1 disappeared, while two new peaks were observed at 3325 and 3126 cm −1 and could be ascribed to N–H sp 2 and N–H sp 3 of melamine. 38…”

“…The diffractogram shows two peaks at 26.35 and 39.5 that correspond to the two characteristic peaks of melamine with a little shi was observed in the position of the former peaks and disappearance of the other peaks, and this conrmed that melamine had participated in the synthesis of the obtained MOF. 38 The peaks at 2q; 17.21 , 25.07 , and 29.57 that represent the terephthalic acid peaks showed a small deviation from the characteristic peaks of pure terephthalic acid. 49 Further three peaks were detected at 13.62 , 27.67 , and 31.76 which could be considered as characteristic peaks of strontium chloride hexahydrate with a small shi from its ideal peaks' positions.…”

“…The peaks recorded at 3396 and 3470 cm À1 could be attributable to the amide linkage's N-H stretching frequency, which proved the formation of an amide linkage between the carboxylic and amine groups of terephthalic and melamine ligands. 38 The peak observed at 1641 cm À1 may be attributed to the presence of stretching C]O that was broadened with multiple splitting. This may be due to the inclusion of C]O through amide linkage, which caused a shi to a lower frequency rather than the C]O peak in terephthalic acid at 1690 cm À1 .…”

“…Besides, the peak of N-H sp 2 of melamine at 3418 cm À1 disappeared, while two new peaks were observed at 3325 and 3126 cm À1 and could be ascribed to N-H sp 2 and N-H sp 3 of melamine. 38 1 H and 13 C NMR spectra. The experimental 1 H NMR spectrum of MTSr-MOF is given in (Fig.…”