Facile synthesis of magnetic CS-g-SPSS microspheres via electron beam radiation for efficient removal of methylene blue

Design, Synthesis and Adsorption Evaluation of Bio-Based Lignin/Chitosan Beads for Congo Red Removal

“…The pure CS beads show obvious degradation from 200 °C, higher than that of raw CS [ 11 ], revealing that the chemical cross-linking with glutaraldehyde is a useful approach to enhancing the thermal stability of the CS. The pure CS beads show two main weight loss stages in the ranges of 200–300 °C and 360–430 °C, which is consistent with the results in the literature [ 13 ]. With the increase of lignin content in the Lig/CS beads, the amount of residue increased from 17.2% to 21.5%, 25.7%, and 31.7% at 500 °C, respectively, demonstrating that the thermal stability of the obtained Lig/CS beads became higher.…”

“…As discussed in the composition analysis ( Figure 3 ), the obtained Lig/CS beads possess easily protonated amino (CS), an aromatic ring (Lig), and a nitrogen (-NH 2 )- and oxygen (-OH)-contained functional group. According to the literature [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ], the CR can be adsorbed onto Lig/CS beads through the combination of electrostatic attraction, π-π stacking, and hydrogen bonding. The obtained Lig/CS beads were used for the adsorption of CR under different conditions.…”

“…The solution pH, which influences the adsorption behavior, is one of the most important factors. The effect of pH value of the CR solution on the adsorption capacity was investigated ( Figure 8 ), and the results clearly revealed the pH-dependent adsorption behaviour of 20% Lig/CS beads toward CR, which demonstrated that the electrostatic attraction played an important role in the removal of anionic CR [ 13 ]. The highest adsorption capacity (159 mg/g) was obtained for the Lig/CS beads containing 20% lignin at a pH = 3, with a removal rate of 79.5%.…”

“…The bio-based lignin/chitosan beads were prepared as follows [ 13 , 28 ] ( Figure 2 ): the lignin was dispersed into 28.5 mL water using a bath sonicator (Kunshan Ultrasound Instrument Co., Ltd., Kunshan, China) for 1 h. Then, 1.5 mL acetic acid and 0.6 g chitosan were added to the lignin dispersion under stirring at 50 °C until complete dissolution (the weight percentage of lignin to chitosan is 0, 10, 20, 40 wt%). Under high-speed stirring at 50 °C, the mixture was then poured into an emulsifier dispersion, which consisted of 1.2 mL Tween-80, 25 mL liquid paraffin wax, and 35 mL petroleum ether.…”

“…In the construction of polymeric adsorbents for dye removal, electrostatic attraction was utilized most popularly due to its ionic characteristic. Among these ionic polymers, the positive chitosan and negative sodium carboxymethyl cellulose/alginate were the most promising candidates [ 13 , 14 , 15 , 16 ]. As all of the dyes are aromatic compounds, adsorbents based on π-π stacking were also developed for the removal, including the lignin- and tannin-based adsorbents [ 17 , 18 ].…”