Edge carboxylation-induced charge separation dynamics of graphene quantum dot/cellulose nanocomposites

Development of L-Met functionalized cellulose nanofiber for an efficient removal of Pb2+ from aqueous solution: Characterization, adsorption behavior, DFT calculations and physiochemical mechanism

Lead-containing wastewater has been a significant challenge in the field of wastewater treatment. Cellulose surface has a large number of active sites, which is conducive to load modification. And amino acids have rich functional groups, which is a good choice for cellulose modification. In this study, the non-toxic L-methionine modified cellulose nanofiber (M-CNF) adsorbent was developed to adsorb Pb2+ in aqueous solution. M-CNF exhibited a maximum adsorption efficiency of 98.24 ± 0.04 %. The theoretical adsorption capacity could reach 113.3 ± 13.4 mg g-1. After five cycles of adsorption-desorption process, the removal efficiency of Pb2+ was still >80 %. The pseudo-second-order kinetic model (R2 = 0.9913) and Brunauer-Emmet-Teller adsorption isotherm model (R2 = 0.9916) can be used to describe the adsorption behavior of M-CNF on Pb2+. The Gibbs free energy (ΔG) and enthalpy (ΔH) of the reaction are negative, indicating that the reaction was a spontaneous exothermic process. Density functional theory calculation indicated that -COOH and -C-S-C- groups played a role in the adsorption process. The adsorption mechanism of M-CNF might be the interaction of ion exchange, electrostatic adsorption, complexation and van der Waals force. This work suggested that M-CNF played a definitive role in the adsorption and removal of Pb2+ in aqueous solutions.

Superhydrophobic modification of cellulosic paper-based materials: Fabrication, properties, and versatile applications

Cellulose is the cheapest and mostly widespread green raw material on earth. Due to the easy and versatile developed modification of cellulose, many cellulosic paper-based sustainable materials and their multifunctional applications have attained increasing interest under the background of the implementation of the "plastic ban" policy. However, intrinsic cellulose paper is hydrophilic and non-water-proof, which highly limited its application, thus becoming a bottleneck for the development of "cellulosic paper-based plastic replacement". Unquestioningly, the superhydrophobic modification of cellulosic paper-based materials and the extension of their high value-added applications are highly desired, which is the main content of this review. More importantly, we presented the comprehensive discussion of the functionalized applications of superhydrophobic cellulosic paper-based materials ranging from conventional products to high value-added functional materials such as paper straw and paper mulch film for the first time, which have great industrialization potential and value. This review would offer the valuable guidance and insightful information for the rational construction of sustainable superhydrophobic cellulosic paper for advanced functional devices.