A novel modified carboxymethyl cellulose hydrogel adsorbent for efficient removal of poisonous metals from wastewater: Performance and mechanism

A cost-efficient and simple method, grafting sodium sulfonate groups (−SO3Na) onto carboxymethyl cellulose (CMC), was developed to form hydrogel adsorbents for the removal of poisonous metals including Cu(Ⅱ) and Zn(Ⅱ) from wastewater. In this work, cellulose-based hydrogels (CMC-g-P(AA-co-SS)) were prepared using acrylic acid (AA) and sodium styrene sulfonate (SS). FTIR, XPS, SEM, and EDX were employed to analyze the surface morphology and structure of CMC-g-P(AA-co-SS). The results revealed that the synergistic effect of −SO3Na and carboxylate groups (−COO−) facilitated the adsorption of heavy metals. Moreover, introducing AA and SS enhanced the swelling degree of CMC hydrogels. The results of adsorption experiments showed that high adsorption efficiencies were obtained for Cu(Ⅱ) and Zn(Ⅱ) (200.44 mg/g and 192.28 mg/g, respectively) within 180 min. The adsorption isotherm and kinetics indicated that the monolayer chemical adsorption dominated the process. After 5 cycles, the adsorption activity of CMC-g-P(AA-co-SS) remained high, with the adsorption capacity for Cu(Ⅱ) and Zn(Ⅱ) being 93.3% and 78.3% of the original, respectively. Thus, the CMC-g-P(AA-co-SS) is a promising adsorbent candidate for the removal of poisonous metals from wastewater.