الفهرس 
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Abstract
In this study a hydrogel was prepared by grafting AM onto GG in the presence of (MBA) as a Icrosslinker using microwave and (APS) to initiate the grafting reaction.
[0 FT-IR characterization was used to proof the grafting reaction. The characteristic absorption at on GG-g-PAM hydrogel for amide group in addition to disappearance of stretching vibration of C=C peak at 1609 cm’1, is a strong evidence for grafting reaction. Also, SEM micrographs show the change in surface morphology of GG-g-PAM hydrogel against pure guar gum.
□ The maximum dye removal percent (66%) was attained at percentage of grafting (892 %) while the lowest dye removal percentage (47%) was attained at percentage of grafting (60 %).
’ □ The initial pH of the adsorbate solution was found to have an important role in the adsorption efficiency. The maximum adsorption capacity (qe) of AR8 dye (18 mg.g’1) was attained at pH 1. The adsorption capacity (qe) of AR8 dye showed decrement in its value by increasing the adsorbate initial pH until it reached (8 mg.g’1) at pH 9.
□ Regarding the effect of contact time, it was found that the adsorption capacity (qe) of AR8 improves from 12 (mg.g’1) after 10 min to reach 16 (mg.g’1) after 60 min.
□ The results of the percent of dye removal using different adsorbent doses showed that, the percent of dye removal on using hydrogel dosage of 0.5 g.L’1 is about 34 %. This percent was found to increase by increasing the hydrogel dosage to reach 87 % on using hydrogel dose of 8.0
g.L’1.
□ The quantity of AR8 sorbed decreased from 34 mg.g _1 to 5.5 mg.g’1 due to increasing of adsorbent dosage (hydrogel) with respect to adsorbate concentration (dye).
□ The data obtained from the adsorption study was found to fit well to Langmuir adsorption model with a maximum adsorption capacity of 54.054 mg.g’ .
□ The kinetic model of adsorption was found to follow pseudo second order kinetics, which assumes that the valance forces through sharing or exchange of electrons between adsorbent and adsorbate are involved in adsorption system.
□ The effect of temperature on adsorption has been studied; it was observed a decrease in the adsorbed quantity (qc) with increasing temperature and the maximum adsorption was obtained at 20°C.
□ Thermodynamically the negative values of AG° and AH0 confirmed the exothermic and spontaneous nature of adsorption, additionally the predominance of the physical adsorption process.