China Petroleum Processing & Petrochemical Technology ›› 2022, Vol. 24 ›› Issue (4): 108-119.

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Activated Carbon from Rice Husk with One-Step KOH Mechanical Mixing Activation as Adsorbent for Treating Phenolic Wastewater#br#

Jiang Bolong1; Jiang Nan1; Shi Shunjie1,2; Cui Yanyan1,2   

  1. 1. Innovation Institute for Sustainable Maritime Architecture Research and Technology, Qingdao University of Technology, Qingdao 266000, Shandong, China;
    2. Institute of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266000, Shandong, China
  • Received:2022-01-18 Revised:2022-02-23 Online:2022-12-30 Published:2022-12-30
  • Contact: Bolong Jiang

Abstract: Phenolic compounds are highly toxic to human beings and harmful to the environment. The aim of this study was to obtain large surface area biocarbons with high phenolic adsorption capacities from cheap and abundant rice husk (RH). For this purpose, the directly mixing of the KOH with RH and activating in flowing N2 atmosphere, namely one-step KOH mechanical mixing activation method was adopted and the effect of the pyrolysis temperature and KOH to RH ratio (x) on the structure of the obtained activated carbon (AC-T-x) adsorbents (T refers the activation temperature of RH in oC) and their adsorptive performances of p-nitrophenol and phenol were studied. The result showed that the optimum pyrolysis temperature of RH was 750 oC. The highest surface area of 2047 m2·g-1 and best adsorption performance were obtained with AC-750-3 prepared with KOH to RH ratio of 3:1. Moreover, it exhibited a maximum adsorption capacity of 175 mg·g-1 for phenol and 430 mg·g-1 for p-nitrophenol, which are higher than most of the reported data. The above results showed that the one-step KOH mechanical mixing activation method is a promising method for RH activation. The adsorption kinetics fitted well with pseudo-second-order model and adsorption isotherms matched the Langmiur model, indicating a monolayer adsorption behavior. The adsorption of phenolic compounds follows mainly the π-π interaction, H-bond mechanisms and hydrophobic interaction.

Key words: Rice husk, activated carbon, KOH activation,, astewater treatment, p-nitrophenol, phenol