| dc.description.abstract | Fertilizer-enriched superabsorbent polymer (SAP) could be used to help water savings, especially in dry areas, and improve the efficiency of fertilizer application compared with conventional method, stocking of fertilizer on the soil surface. In this research, several kinds of SAP were synthesized by grafting copolymerization of 40% neutralized acrylic acid with onggok (solid waste of tapioca factory) by using ammonium persulfate as initiator and by varying the amount of crosslinker N,N'-methylene-bis-acrylamide and urea added. Water absorption capacity of SAP before enrichment was 730.48 g/g with nitrogen content of 4.12%, and decreased after enriched by urea. For 0.025, 0.050, and 0.100 g of crosslinker, water absorption capacities were 293.38, 227.34, and 209.20 g/g and nitrogen contents were 17.99, 16.49, and 16.83%, respectively. Nitrogen release study of enriched SAP with 0.025 and 0.050 g of crosslinker showed nitrogen release of 6.29 and 7.35%, respectively while SAP with 0.100 g of crosslinker at the same time only released 23.92% of nitrogen. These results indicated that the amount of crosslinker greatly influenced the pattern of release of urea. | en |
