Alternative treatments to improve the potential of rice husk as adsorbent for methylene blue

Dison S.P. Franco, Eduardo H. Tanabe, Daniel A. Bertuol, Glaydson S. Dos Reis, Éder C. Lima, Guilherme L. Dotto*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

45 Citations (Scopus)

Abstract

Alternative treatments, such as, NaOH, ultrasound assisted (UA) and supercritical CO 2 (SCO 2 ), were performed to improve the potential of rice husk as adsorbent to remove methylene blue (MB) from aqueous media. All the treatments improved the surface characteristics of rice husk, exposing its organic fraction and/or providing more adsorption sites. The Langmuir and Hill models were able to explain the MB adsorption for all adsorbents in all studied temperatures. The experimental and modeled parameters demonstrated that the MB adsorption was favored by the temperature increase and by the use of NaOH-rice husk. The maximum adsorption capacities for the MB solutions (ranging from 10 to 100 mg L -1 ), estimated from the Langmuir model at 328 K, were in the following order: NaOH rice-husk (65.0 mg g -1 )UA-rice husk (58.7 mg g -1 )SCO 2 -rice husk (56.4 mg g -1 ) raw rice husk (52.2 mg g -1 ). The adsorption was a spontaneous, favorable and endothermic process. In general, this work demonstrated that NaOH, UA and SCO 2 treatments are alternatives to improve the potential of rice husk as adsorbent.

Original languageEnglish
Pages (from-to)296-305
Number of pages10
JournalWater Science and Technology
Volume75
Issue number2
DOIs
Publication statusPublished - Jan 2017
MoE publication typeA1 Journal article-refereed

Keywords

  • Adsorption
  • Methylene blue
  • Rice husk
  • Surface modification

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