Synthesis of Cellulose–Poly(Acrylic Acid) Using Sugarcane Bagasse Extracted Cellulose Fibres for the Removal of Heavy Metal Ions

Abstract

In this study, sugarcane bagasse (SCB) was treated with sodium hydroxide and bleached to separate the non-cellulose components to obtain cellulose (CE) fibres. Cross-linked cellulose–poly(sodium acrylic acid) hydrogel (CE–PAANa) was successfully synthesised via simple free-radical graft-polymerisation to remove heavy metal ions. The structure and morphology of the hydrogel display an open interconnected porous structure on the surface of the hydrogel. Various factors influencing batch adsorption capacity, including pH, contact time, and solution concentration, were investigated. The results showed that the adsorption kinetics were in good agreement with the pseudo-second-order kinetic model and that the adsorption isotherms followed the Langmuir model. The maximum adsorption capacities calculated by the Langmuir model are 106.3, 333.3, and 163.9 mg/g for Cu(II), Pb(II), and Cd(II), respectively. Furthermore, X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectrometry (EDS) results demonstrated that cationic exchange and electrostatic interaction were the main heavy metal ions adsorption mechanisms. These results demonstrate that CE–PAANa graft copolymer sorbents from cellulose-rich SCB can potentially be used for the removal of heavy metal ions.

Synthesis, Characterization, and Evaluation of the Adsorption Behavior of Cellulose-Graft-Poly(Acrylonitrile-co-Acrylic Acid) and Cellulose-Graft-Poly(Acrylonitrile-co-Styrene) towards Ni(II) and Cu(II) Heavy Metals

“…Figure 3b represents IR of C-g-P(AN-co-AA) and Cell-g-P(AN-co-Sty) after adsorption of Ni(II) and Cu(II) ions. The peak of C=O group in Cell-g-p(AN-co-AA) exhibited low intensity and shifted to 1770 and 1762 cm −1 , due to the formation of complexes with Ni(II) and Cu(II) metal ions [37,65]. Furthermore, the peaks of C-H aromatic group and aromatic ring in Cell-g-P(AN-co-Sty) shifted to1528 and795 cm −1 after adsorption of Ni(II), respectively, and also shifted to 795 and 788 cm −1 after adsorption of Cu(II) ions, respectively.…”

“…The final decomposition temperature was at 530 • C with 9% residue left. From TG curves, it can be observed that grafting of AN decreases the thermal stability of cellulose, while grafting of the binary mixture increases the thermal stability of cellulose, compared to individual monomers as well as to their other binary mixtures [32,35,37,55,59], especially in the presence of polystyrene.…”

“…In recent decades, cellulose and its bio-renewable fiber as adsorbents have become the most common low-cost biopolymer. Since the adsorption capacity of cellulosic raw materials is restricted, cellulose needs to be chemically treated to produce an effective adsorption activity [35][36][37]. The coveted recyclable, non-toxic, biodegradable, and environmentally beneficial features of cellulose-based grafted copolymers have always piqued the interest of researchers.…”

“…The purpose of our study was to prepare an improved chemically modified cotton cellulose fiber (Cell) that exhibited higher thermal stability and efficient adsorption capacity using low-cost and simple method, KMnO 4 /citric acid redox initiator [58], by introducing new binary Acrylonitrile (AN)/acrylic (AA) acid and also acrylonitrile/styrene (Sty) mixtures into cellulose fibers as novel graft copolymers, compared to individual monomers as well as to their other binary mixtures [32,35,37,55,59]. Moreover, we aimed to assess the behavior of Cell-g-P(AN-co-AA) and Cell-g-P(AN-co-Sty) for Ni(II) and Cu(II) metal ions and to determine the underlying mechanisms.…”

“…Accordingly, the adsorption behavior of Cell-g-P(AN-co-AA) and Cell-g-P(AN-co-Sty) towards Ni(II) and Cu(II) metal ions from aqueous medium were examined at different adsorption factors, such as adsorption contact time, pH medium, adsorption temperature, and initial metal ion concentration, to determine the optimized adsorption conditions. The adsorption data were applied in different adsorption isotherm models for evaluating the sorption mechanism and also were compared with other studies [32,35,37,[55][56][57]59] to investigate the effect of the graft polymerization initiation system and the type of binary monomer mixture on the adsorption efficiencies towards heavy metal ions removal.…”