Novel Mesoporous Lignin-Calcium for Efficiently Scavenging Cationic Dyes from Dyestuff Effluent

Abstract

A novel adsorbent lignin-calcium was fabricated by a simple flocculation–sedimentation approach to remove methylene blue. The structure and morphology of the well-prepared sample were analyzed by multiple characterization methods. Lignin-calcium microspheres demonstrated a mesoporous and inserted layer structure with a coarse surface. Methylene blue (MB) adsorption by lignin-calcium complied with the Langmuir model, showing a maximum adsorption amount of 803.9 mg/g, exceeding that reported in the literature by 3–22-fold. The adsorption kinetics matched the pseudo-second-order model well. The pore volume diffusion model was technically applied to evaluate the mass transfer mechanisms. The effective pore volume diffusion coefficient was 6.28 × 10–12 m2/s. Furthermore, lignin-calcium exhibited excellent adsorbability for methylene blue across a pH range from 3 to 11 and could be regenerated by hydrochloric acid with an elution efficiency of 62.44%. Multiple mechanisms may support the adsorption. Altogether, the tailor-made lignin-calcium is promising as an efficient and sustainable adsorbent for scavenging cationic dyes from dyestuff effluent.

Chemical Transformation of Lignosulfonates to Lignosulfonamides with Improved Thermal Characteristics

“…Additionally, research concentrating on utilizing dihydroxybenzophenone-grafted lignin with high UV absorbance was described, and the obtained product showed great promise as an alternative for commercial sunscreens [27]. The intrinsic absorption abilities of lignin were further enhanced by either introduction of the calcium counter-ions [28] or grafting with poly There are four known methodologies used for the extraction of lignin from the lignocellulosic biomass. Two grades of technical lignins-Kraft lignin and lignosulfonates, collectively known as sulfur lignins-are obtained as a by-product in the paper and pulping industry in the processes requiring the sulfur-based compounds.…”

“…Additionally, research concentrating on utilizing dihydroxybenzophenone-grafted lignin with high UV absorbance was described, and the obtained product showed great promise as an alternative for commercial sunscreens [27]. The intrinsic absorption abilities of lignin were further enhanced by either introduction of the calcium counter-ions [28] or grafting with poly (acrylic acid) [29]. Such-prepared materials proved effective in scavenging the cationic dyes from the dyestuff effluents [28] and show great promise in the selective absorption of ofloxacin and ciprofloxacin [29].…”

“…The intrinsic absorption abilities of lignin were further enhanced by either introduction of the calcium counter-ions [28] or grafting with poly (acrylic acid) [29]. Such-prepared materials proved effective in scavenging the cationic dyes from the dyestuff effluents [28] and show great promise in the selective absorption of ofloxacin and ciprofloxacin [29]. Current studies also investigate the usage of the lignin-based prod-uct as wood adhesives for medium-density fiberboards [30] or functional hydrogels with conductive properties, with the potential to use them as a sunscreen or even flexible electronic skin [31].…”

Emulsion-Templated Porous Polymers for Efficient Dye Removal

“…In Figure 5 , the probable interactions between the dye molecules and the porous polymer can be seen. 20 , 37 …”

“…Also, hydrogen bonds and van der Waals forces contribute to dye adsorption. In Figure , the probable interactions between the dye molecules and the porous polymer can be seen. , …”