MODIFICATION OF SILICA GEL SURFACE BY POLYACRYLAMIDE THROUGH THE REDOX INITIATION OF CERIC AMMONIUM NITRATE - SODIUM SULFITE SYSTEM

In-situ polymerization of acrylamide(AAM) and modification of silica gel surface were extensively studied. The entire different factors affecting the process were optimized aiming at obtaining a product in a maximum yield and high nitrogen content. The obtained results indicated that sodium sulfite is the key issue of the initiation and completeness of both polymerization and modification. Moreover, silica gel itself exerted also an important role in the entire process. The optimum conditions for in-situ modification of 5g silica gel via polymerization of an aqueous acrylamide (5g/50ml) were: 1mM of ceric ammonium nitrate, 120 minutes, 70oC and 0.15g of Na2SO3 as an activator. The synthesized modified samples and silica gel were characterized by elemental analysis (only for the modified samples) FT-IR, XRD, SEM , and differential thermal analysis(DTA ).