Acid precipitation coupled membrane-dispersion advanced oxidation process (MAOP) to treat crystallization mother liquor of pulp wastewater

Rongzong Li, Zhaoyang Li, Qian Jiang, Zhaoxiang Zhong, Ming Zhou, Weihong Xing

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Treatment to crystallization mother liquor containing high concentration of organic and inorganic substances is a challenge in zero liquid discharge of industrial wastewater. Acid precipitation coupled membrane-dispersion advanced oxidation process (MAOP) was proposed for organics degradation before salt crystallization by evaporation. With acid–MAOP treatment CODCr in mother liquor of pulping wastewater was eliminated by 55.2% from ultrahigh initial concentration up to 12,500 mg·L−1. The decolorization rate was 96.5%. Recovered salt was mainly NaCl (83.3 wt%) having whiteness 50 brighter than industrial baysalt of whiteness 45. The oxidation conditions were optimized as CO3 = 0.11 g·L−1 and CH2O2 = 2.0 g·L−1 with dispersing rate 0.53 ml·min−1 for 100 min reaction toward acidified liquor of pH = 2. Acidification has notably improved evaporation efficiency during crystallization. Addition of H2O2 made through membrane dispersion has eliminated hydroxyl radical “quench effect” and enhanced the degradation capacity, in particular, the breakage of carbon–chloride bonds (of both aliphatic and aromatic). As a result, the proposed coupling method has improved organic pollutant reduction so as the purity of salt from the wastewater mixture which can facilitate water and salt recycling in industry.

Original languageEnglish
Pages (from-to)1911-1917
Number of pages7
JournalChinese Journal of Chemical Engineering
Volume28
Issue number7
DOIs
StatePublished - Jul 2020

Keywords

  • Advanced oxidation process
  • Ceramic membrane dispersion
  • Crystallization mother liquor
  • Pulping wastewater

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