Eco-Friendly Dye Adsorbent from Poly(vinyl amine) Grafted Onto Bacterial Cellulose Sheet by Using Gamma Radiation-Induced Simultaneous Grafting and Base Hydrolysis

N-vinylformamide (NVF) was successfully grafted onto a bacterial cellulose (BC) sheet through gamma radiation-induced simultaneous grafting. The optimum conditions for grafting were an irradiation dose of 15 kGy and an NVF concentration of 30%vol. The resulting product, poly(vinyl formamide)-grafted-bacterial cellulose sheet (PNVF-g-BC) was hydrolyzed using a basic medium to obtain poly(vinyl amine)-grafted-BC (PVAm-g-BC) as an eco-friendly dye adsorbent. The maximum degrees of NVF grafting and hydrolysis were 98.89 ± 3.95% and 88 ± 0.55%, respectively. Chemical, binding energy, crystalline, thermal, and morphological characterizations of the starting materials, as well as PNVF-g-BC and PVAm-g-BC adsorbents, were conducted. Batch tests were performed to investigate the efficiency of methylene blue (MB) adsorption and the adsorption capacity of the PVAm-g-BC adsorbent. The effects of initial MB concentration, time, and pH on the adsorption were studied. The maximum adsorption capacity of the adsorbent was 7.78 ± 0.41 mg/g at an MB concentration of 10 mg/L, pH 13, and a reaction time of 8 h. The adsorption behavior of MB onto the adsorbent was found to fit the Langmuir isotherm model, indicating monolayer adsorption. The adsorption/desorption study demonstrated that the adsorbents could be reused for 6 cycles with effective performance for MB adsorption (> 50%). This eco-friendly dye adsorbent exhibits outstanding properties as a potential candidate for dye adsorption. Graphical Abstract