Abstract-Fertilizer and water are very important in determining the production of agriculture nowadays. Apart of that, the excessive use of fertilizer in plantation somehow could leads to environmental pollution. The present study reported a preparation of controlled release water retention (CRWR) fertilizer coated with superabsorbent polymer (SAPs). The purpose of coating the fertilizer using SAPs is to enhance the utilization of fertilizer and reduce the environmental pollution. In this study, the synthesis of carbonaceous-SAPs was carried out via solution polymerization technique by using monomers of poly(acrylic acid) (AA) and acrylamide (AM), cross linker of methylene bisacrylamide (MBA) and initiator of ammonium peroxodisulfate (APS) that partially neutralized with sodium hydroxide (NaOH). The fertilizer granule then was coated with carbonaceous-SAPs which later known as CRWR fertilizer. The morphology and the bonding formation of the CRWR fertilizer were investigated by using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectrophotometer (FTIR), respectively. Moreover, the water absorbency and water retention in soil were conducted in order to investigate the efficiency of carbonaceous-SAPs on the properties of CRWR fertilizer. Based on the results, it was found that the CRWR fertilizer coated with carbonaceous-SAPs had higher water absorbency and water retention ability than the CRWR fertilizer without carbonaceous-SAPs. The addition of the carbonaceous filler in the formulation of SAP increase the water uptake compared to unfilled-SAP. Moreover, types of soil also play an important factor in water retention properties. CRWR fertilizer in organic soil results in higher water retention ability compared in top soil.

Superabsorbent polymers (SAPs) are crosslinked three dimensional structures that poses high swelling capacity in aqueous medium. Its application in agriculture beneficial as it is able to retain moisture in soil. SAPs incorporated with bio-char have been prepared via solution polymerization of polyacrylic acid with co-monomer of polyacrylamide in the presence of bio-char using methylenebisacryalmide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. In this research, the swelling kinetic behavior of SAP with biochar was studied on the effect of biochar percentage loading from 0-0.8wt. SEM imaging of sap icorporated biochar shows a porous structure which influences water absorbency. The maximum of water absorbency capacity reached an optimum value of 129.89 g/g at 0.4 % before decreasing with increasing bio-char loading. Mathematical model of kinetic diffusivity also revealed that the SAP-biochar incorporated follows a second order kinetic. The presence of bio-char could enhance physical properties by increasing the water-holding capacity, enhancing its water absorbency ability. Application of SAP incorporated biochar not only able to retain water, it could also help to fertilize agriculture.

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Abstract. Utilisation of fertilizer and water are very important in determining the production of agriculture nowadays. The excessive use of fertilizer in plantation somehow could leads to environmental pollution. The present study reported a synthesis of controlled release water retention (CRWR) fertilizer coating with superabsorbent polymer (SAPs). Superabsorbent polymer (SAPs) are polymers that have ability to absorb and retain large amounts of water relative to their own mass. The presence of coating layer of SAPs on fertilizer granules was believed could reduce excessive used of fertilizer by controlling their dissolution rates and also reduce the environmental pollution. In this study, the effect on the addition of carbonaceous filler in SAPs on the water absorbency was also be compared with control SAPs (without carbonaceous particles). In this study, the carbonaceous filler were obtained from pyrolysis process of empty fruit bunch (EFB) biomass. The synthesized of SAPs and carbonaceous-SAPs were carried out via solution polymerization technique by using monomer of poly(acrylic acid) (AA), acrylamide (AM), cross linker, methylene bisacrylamide (MBA) and initiator, ammonium peroxodisulfate (APS) that partially neutralized with sodium hydroxide (NaOH). The CRWR fertilizer was later be prepared by coated the fertilizer granule with SAPs and carbonaceous-SAPs. The water absorbency, morphology and the bonding formation of both CRWR fertilizer were investigated by using tea-beg method, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectrophotometer (FTIR), respectively. Moreover, the water retention studies was conducted in order to investigate the efficiency of CRWR coated with SAP and carbonaceous-SAP in retaining the water content in different soil (organic and top soil). Based on the results, the CRWR fertilizer that was coated with carbonaceous-SAP had higher water absorbency value than the CRWR fertilizer without carbonaceous-SAP. Meanwhile, 1 wt % CRWR fertilizer in organic soil gave higher water retention ability compared with 1 wt % CRWR fertilizer in top soil. In conclusion, CRWR fertilizer coated with carbonaceous filler gave a significant influence on the water absorbency and in controlling the nutrients release rate as well as function as water retention in soil.