Abstract
The management of disposable diapers is a major problem. Moreover, light-textured soils are characterized by low
water holding capacity and excessive drainage, thus significant portion of irrigation water is lost below the root zone. A
laboratory study was conducted to evaluate the potential of recycling disposable baby diapers to conserve soil moisture
in light-textures soils. The water absorbency [water absorption capacity (WAC) and water absorption rate (WAR)] of the
recovered Super absorbent polymers (SAPs), from diapers, was evaluated and described under different ionic solute
strengths (0.0, 0.5, 1.0, 2.0, 3.0 and 4.0 dS m-1
) at different time periods. Additionally, several swelling measurements of
the SAPs were determined when added to sandy clay loam soil using different levels [0.0, 0.4, 0.6, 0.8 and 1.6% (w/w)]
for five rewetting cycles (over a period of 6 months). As the swelling time increased, the WAC increased, while WAR
decreased. However, both WAC and WAR were reduced as the solution salinity increased. The recovered SAPs exhibited
WAC of 311.0 and 111.0 g g-1
in solution of 0.0 and 3.0 dS m-1
, respectively. Polynomials functions were used to
calculate the equilibrium time and threshold solute concentration for the SAPs. The average equilibrium time was 4.5
minutes and the threshold solute concentration was 2.78 dS m-1
. At SAPs concentration of 1.6%, the water retained by
the soil increased by 2.6 folds. The specific amount of water retained (SWR) by SAPs in the SAPs-soil mixture was
decreased with repeating wetting, thus, after 6 months, the average WHC of the soil was decreased by 14% compared to
initial wetting. The recycling of baby diapers might have a great potential to conserve soil moisture in light soils using
water of good quality. However, since the SAPs in diapers are Na+ based, further research is needed to explorer the
impact of such treatment on soil chemical properties.
Madiha Zekry, Ibrahim Nassar, Heba Salim , Ahmed Abdallah. (2020) The Potential of super absorbent polymers from diaper wastes to enhance water retention properties of the soil, The Journal Soil & Environment , Volume 39, Issue 1.
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