Magnetic composite Ca(OH)2/Fe3O4 for highly efficient flocculation in papermaking black liquor without pH neutralization

Kun Dai, Peng Chen, Zichen Wang, Pengpeng Yang, Ming Li, Chenglun Tang, Wei Zhuang, Chenjie Zhu, Hanjie Ying, Jinglan Wu

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Industrially, lignin in pulp liquor not only obstructed the realization of value-added products, but also threatened the aquatic ecosystem. A magnetic composite Ca(OH)2/Fe3O4, combining the eco-friendliness of Ca-based flocculants with the convenience of magnetic flocculation, was simply compounded to efficiently flocculate lignin from papermaking black liquor. Morphologic and structural features of the flocculant before and after flocculation were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM) and X-ray photoelectron spectroscopy (XPS). The flocculant Ca(OH)2/Fe3O4 presented mesoporous and core-shell structure, which acted directly in the sodium lignin aqueous solution without pH neutralization, maintaining high lignin removal between 91% and 95%. Ca(OH)2/Fe3O4 showed a wider salts (0–1 mol/L NaCl) and pH (9–12.5) tolerance. In actual pulp black liquor, Ca(OH)2/Fe3O4 exhibited high removal of 90.16% and 85.93% for lignin and chemical oxygen demand (COD), respectively. The flocculation performance of Ca(OH)2/Fe3O4 outdistanced that of the traditional flocculant polyacrylamide (PAM). It displayed magnetically separable with a good reusability. The removal of lignin could attain 90.54% even after 6 cycles. Charge neutralization, micro-bridging, destabilization and sedimentation were involved in the process of lignin flocculation. Consequently, Ca(OH)2/Fe3O4 presented huge potential in papermaking black liquor treatment.

Original languageEnglish
Pages (from-to)2457-2468
Number of pages12
JournalAdvanced Powder Technology
Volume32
Issue number7
DOIs
StatePublished - Jul 2021

Keywords

  • Flocculation performance
  • Lignin
  • Magnetic flocculant
  • Pulp black liquor

Fingerprint

Dive into the research topics of 'Magnetic composite Ca(OH)2/Fe3O4 for highly efficient flocculation in papermaking black liquor without pH neutralization'. Together they form a unique fingerprint.

Cite this