Methylene blue removal by poly(acrylic acid)-grafted pineapple leaf fiber/polyester nonwoven fabric adsorbent and its comparison with removal by gamma or electron beam irradiation

This work aimed to synthesize poly(acrylic acid)-grafted pineapple leaf fiber/polyester nonwoven fabric (PPNWF-g-PAA) through radiation-induced graft polymerization. The synthesized PPNWF-g-PAAs were used as adsorbents for methylene blue (MB) adsorption in aqueous solution. The grafting was performed with a systematic variation of experimental parameters in order to produce PPNWF-g-PAA with a degree of grafting of at least 150%. Based on the results, the optimum experimental parameters were the following: irradiation with 2.0 MeV of energy, current of 12 mA, 30 kGy of absorbed dose, and grafting with 20% acrylic acid at 40 degrees C for 3 h. Results of the batch adsorption experiments revealed that PPNWF-g-PAA successfully adsorbed MB from aqueous solution with a contact time of about 3 h. The efficiency of MB adsorption was also compared with direct MB degradation through gamma or electron beam irradiation. Results of the irradiation experiments revealed that a minimum of 5 kGy was required in order to achieve complete removal of the MB molecules using direct irradiation which is lower than the absorbed dose requirement for the synthesis of PPNWF-g-PAA. However, the MB removal using the adsorbent does not generate degradation products unlike the MB removal using direct irradiation.