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Selection of desired bentonite and evaluating influence of different acids on preparation of special clay for removal of trace olefins from aromatics

Rouhani, H ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1180/clm.2021.32
  3. Publisher: Cambridge University Press , 2021
  4. Abstract:
  5. Activated clay is an inexpensive substance with massive utilization for removal of unsaturated compounds on an industrial scale. The performance of activated clay in removing such compounds heavily relies on the type of pristine raw clay and acids which are used during the activation process. In this work, olefins removal from aromatic streams is reported by activated clays with two different routes of clay activation. After preliminary tests of four different natural clays, the best clay was selected due to having enhanced swelling index, cation exchange capacity, higher surface area, and better suspension stability, among others. Having activated clay with hydrochloric acid and sulfuric acid, olefin removal was evaluated after a wholistic clay characterization by means of X-ray Diffraction (XRD), X-ray Fluorescence (XRF), BET surface area analysis, Zeta potential, Pyridine-FTIR, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Increased basal spacing, replacement of H+with interlayer cations, and retained structural stability of clay against acid-treatment were found as the reasons contributing to improved olefin removal for HCl-treated activated clay. With HCl being more efficient than H2SO4, HCl-activated sample could remove olefin components up to 90% in 40 hr. Based on Pyridine-FTIR spectra and quantitative measurement of acidic properties of samples showed that HCl acid-treatment increases total acid sites (Brønsted & Lewis) about 9 times more than the pristine natural clay and about 4 times more than the H2SO4activated clay. © 2021 Cambridge University Press. All rights reserved
  6. Keywords:
  7. Bentonite ; Chemical activation ; Fourier transform infrared spectroscopy ; High resolution transmission electron microscopy ; Olefins ; Oxidants ; Positive ions ; Scanning electron microscopy ; Stability ; Acid treatments ; Activated clay ; Industrial scale ; Interlayer cation ; Natural clays ; Olefin removal ; Performance ; Pyridine FTIR ; Raw clay ; Special clays ; Chlorine compounds
  8. Source: Clay Minerals ; 2021 ; 00098558 (ISSN)
  9. URL: https://www.cambridge.org/core/journals/clay-minerals/article/selection-of-suitable-bentonite-and-the-influence-of-various-acids-on-the-preparation-of-a-special-clay-for-the-removal-of-trace-olefins-from-aromatics/9B49B1C3402EEA16BE3FDB7088FB29BF