Document Type : Research Paper

Authors

• Esmaeil Rahbar
• Shahram Banedjschafie

Abstract

The superabsorbent polymers absorb and retain large quantities of water when applied into the soil. This capability is due to its physical and chemical properties. The objectives of this study were to investigate the effects of soil salts on polymer and manure water uptake ability under repeated wetting and drying cycles. The results showed that 1.0 g polyacrylamide made of Iran, had ability to uptake 184.4g distilled water for the first time absorption. It was much less than the same material that had reported in foreign publications. The ability of water retaining for the same polymers was dramatically decreased to 31, 79 and 83 percent than control treatment(distilled water) for waters with 160, 1000 and 2000 mg/l salt concentration, respectively. By 9 times repeated wetting and drying cycles, the ability of polymer had decreased to 22 percent of the first times absorption. As consequently, the amounts of water uptake had also decrease to 72, 81 and 88 percent of distilled water in the same salts after 9 times repeated wetting and drying cycles. At the hottest times of the summer, drying of poly acryl amide super absorbent had take 6 and 2.3 days for distilled and salty water, respectively. The results showed that the negative effects of Na⁺ were less than those for Ca²⁺ and Mg²⁺ on polymer water absorption. For completely decayed animal manure, the retaining of distilled water was 2.3g for 1g dry manure. For water having 4000 mg/l salts concentrations, the uptake ability of manure was not significantly different than distilled water. The drying period of manure had taken the 17 and 18 days for distilled and salty water, respectively.
 

Keywords

• Polyacrylamide
• Manure
• superabsorbent
• salt effect
• water uptake