Two-pot Oxidative Preparation of Dicarboxylic Acid Containing Cellulose for the Removal of Beryllium (Be2+) from Aqueous Solution

Background: Cellulose is one of the most abundant, non-toxic, and renewable natural biopolymers. The presence of hydroxyl groups in cellulose leads to further modification of it. Preparation and modification of cellulose-based sorbents and their applications on water treatment gained traction in recent years. Objective: A low-cost and eco-friendly biosorbent was designed and fabricated by introducing the acetate functional groups into cellulose for removing Beryllium (Be2+) from an aqueous solution. The sorption of Be2+ on acetate containing cellulose was evaluated for varying sorbent doses and initial solution pH values. Methods: The sorbent was prepared by a two-step oxidation process. In the initial step, cellulose reacted with NaIO4 and aldehyde groups were introduced to the cellulose. In the second step, newly obtained aldehyde groups were oxidized to create acetate groups. Results: The kinetics of the sorption process showed that Be2+ uptake reached equilibrium in 3 minutes. The sorption isotherm was well fitted in the Langmuir model, and the maximum sorption capacity was 4.54 mg/g. Moreover, the thermodynamic studies demonstrated that Be2+ sorption was spontaneous and exothermic. Furthermore, the prepared sorbent can be regenerated by using 0.1 M HCl or H2SO4 solutions. Conclusion: It is concluded that the removal of Be2+ is pH-dependent and it is favorable at high solution pH. The kinetics of the prepared sorbent were rapid and equilibrium attained in 3 minutes. The prepared sorbent can be regenerated with 0.1 M acid solution with > 99% efficiency.