Functionalized microspheres with co-participated lignin hybrids as a novel sorbents for toxic CI Basic Yellow 2 and CI Basic Blue 3 dyes removal from textile sewage

The paper presents the synthesis of novel adsorbents in spherical form based on divinylbenzene, ethylene glycol dimethylacrylate and triethoxyvinylsilane, and lignin or its modified form with ZrO2 and SiO2, as hybrid materials of well-defined microstructural factors. In the first stage of the experiment, lignin was mechanochemically combined with the inorganic oxides in form of zirconia and silica. Then, the obtained material was used as a modifier in the preparation of the functionalized polymeric microspheres using the suspension polymerization method. To confirm the chemical structure of the lignin-based hybrid modifiers and the polymeric sorbents, ATRFTIR and XPS spectroscopy as well as SEM analysis were performed. In addition, the parameters of the porous structure were determined. It was shown that mainly physical interactions occur between the inorganic and organic components, resulting in the formation of class I hybrid systems. Subsequently, the functionalized polymeric microspheres were used as effective sorbents of hazardous C.I. Basic Yellow 2 (BY2) and C.I. Basic Blue 3 (BB3) days from textile wastewaters. Equilibrium data for the sorption of BY2 and BB3 by the newly designed adsorbents show that Freundlich isotherm model describes the experimental data more appropriate than the Langmuir or Dubinin-Radushkevich ones. The Freundlich constant related to adsorption capability, kF, enlarged with rising amount of lignin, zirconia and silica, from 42.3 to 83.5 mg(1-1/n) L-1/n/g for BB3 and from 11.1 to 45.7 mg(1-1/n) L-1/n/g for BY2. Kinetic studies revealed favorable uptake of 50 mg/L BB3 during the first 60 min of phase contact time, compared with BY2. Anionic and non-ionic surfactants (0.25 g/L) and NaCl (25 g/L) slightly decreased dyes (50 mg/L) sorption from dyeing baths, and their retention was significantly reduced when a cationic surfactant was present in the bath. Desorption of BB3 and BY2 dyes from the hybrids, with yield in the ranges 20.8-32.0% and 24.8-99.0% respectively, was achieved applying 1 M HCl in the presence of 50% v/v methanol.

Automated summary

This paper presents the synthesis of novel adsorbents and their application in the removal of hazardous dyes from wastewater. The results show that the functionalized polymeric microspheres exhibit good adsorption capability, making them effective sorbents for dye removal.