A new type of highly efficient fir sawdust-based super adsorbent: Remove cationic dyes from wastewater

Abstract

It is still a challenge to prepare dye adsorbents with a favorable separation capacity, a remarkable adsorption capacity, a high removal rate and certain reusability. In this study, a new type of gel (i.e., AA-DWF-PAM) was prepared with treated fir sawdust and verified to be an effective adsorbent for removing cationic dyes in water. The adsorption properties of AA-DWF-PAM were systematically explored by taking methylene blue (MB) and methyl violet (MV) as representative cationic dyes and methyl orange (MO) and carmine (CM) as representative anionic dyes. Through experiments, it is concluded that the most ideal adsorption effect will be achieved under the following parameters: the particle size of AA-DWF-PAM: 60–100 meshes, content: 5 g/L, pH of the solution: 4, temperature: 35 ℃. Furthermore, the adsorption process shows good correlations with the Langmuir isotherm and the pseudo-second-order kinetic model. The maximum adsorption capacities of AA-DWF-PAM for MB and MV are 499.27 mg/g and 481.71 mg/g, respectively, and it is easy to desorb in 0.05 mol/L HCl solution. In addition, through the molecular dynamics simulation technology, it is verified that the adsorption mechanisms behind the adsorption of AA-DWF-PAM include both physical and chemical adsorption represented by electrostatic interaction, hydrogen bonds and van der Waals force. Due to its sustainability, low cost and excellent adsorption performance, AA-DWF-PAM is expected to serve as an adsorbent applied to water treatment.