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Acid Digestion

The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform

Andrew T. Harris – 1st expert on this subject based on the ideXlab platform

  • a review of carbon nanotube purification by microwave assisted Acid Digestion
    Separation and Purification Technology, 2009
    Co-Authors: Kieran J Mackenzie, Oscar Dunens, Andrew T. Harris

    Abstract:

    Carbon nanotube purification by microwave assisted Acid Digestion has been reviewed. Microwave assisted purification demonstrates significant efficiency improvements over traditional Acid reflux with minimal carbon nanotube damage under optimized conditions. This review discusses potential sources for this performance improvement and how best to exploit the technique for economical industrial scale carbon nanotube purification. A review of current literature demonstrates that the effect of key variables such as Acid type and concentration, temperature, duration and pressure are not well understood and, due to their dependence, must be probed with correct experimental design to elucidate potential interaction effects.

  • A review of carbon nanotube purification by microwave assisted Acid Digestion
    Separation and Purification Technology, 2009
    Co-Authors: Kieran Mackenzie, Oscar Dunens, Andrew T. Harris

    Abstract:

    Carbon nanotube purification by microwave assisted Acid Digestion has been reviewed. Microwave assisted purification demonstrates significant efficiency improvements over traditional Acid reflux with minimal carbon nanotube damage under optimized conditions. This review discusses potential sources for this performance improvement and how best to exploit the technique for economical industrial scale carbon nanotube purification. A review of current literature demonstrates that the effect of key variables such as Acid type and concentration, temperature, duration and pressure are not well understood and, due to their dependence, must be probed with correct experimental design to elucidate potential interaction effects. © 2009 Elsevier B.V. All rights reserved.

  • Microwave-assisted Acid Digestion of alumina-supported carbon nanotubes
    Separation and Purification Technology, 2008
    Co-Authors: Andrew T. Harris

    Abstract:

    Abstract Microwave-assisted Acid Digestion was assessed for the purification of carbon nanotubes (CNTs), synthesised in a fluidised-bed by chemical vapour deposition (CVD) on alumina-supported catalysts. The effects of (i) Digestion time (10, 20 or 30 min), (ii) temperature (120, 180 or 230 °C) and (iii) Acid type (HNO 3 , 12.8 mol/L or H 2 SO 4 , 4.4 mol/L) were investigated. Thermogravimetric analysis (TGA) results show that CNT purity increases with increasing Digestion time and temperature, from 2.6 wt% in the as-synthesised bed material to 67.9 wt% for samples treated at 230 °C in H 2 SO 4 for 30 min. Raman spectra show bands corresponding to disordered and sp 2 -bonded crystalline graphitic carbon at approximately 1350 and 1580 cm −1 respectively. These Raman results further suggest that microwave-assisted purification is effective at removing amorphous carbon and defects from the outer CNT tube walls. TEM and HRTEM images suggest that CNTs are able to exist in contact with strong oxidizing Acids at high temperatures in a microwave, and in particular, that it causes no damage to the CNT walls. Microwave-assisted Acid Digestion is able to achieve comparatively high purity from low-quality feedstocks in less than 30 min.

Luc Moens – 2nd expert on this subject based on the ideXlab platform

  • determination of trace elements in agricultural soil samples by inductively coupled plasma mass spectrometry microwave Acid Digestion versus aqua regia extraction
    Analytica Chimica Acta, 2005
    Co-Authors: Samuel Melaku, Richard Dams, Luc Moens

    Abstract:

    Microwave Acid Digestion and aqua regia extraction techniques were investigated to obtain a simple, rapid and safe method for the determination of eight trace elements in soil (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn). Soil samples were collected between 6 October and 3 November 2004, air dried, grinded, sieved (<63 μm) and subjected to Digestion. The digests were subsequently analyzed for metal content by inductively coupled plasma-mass spectrometry (ICP-MS). Various combinations and volumes of hydrofluoric, nitric and hydrochloric Acids were evaluated for the microwave Acid Digestion efficiency. Two certified reference materials (CRM 142, light sandy soil, and CRM 143, over fertilized soil) were used in the comparison of these Digestion protocols and good agreement between the two procedures and the certified values was found. The aqua regia microwave Acid Digestion with a mixture of 2 ml of HNO3 and 6 ml of HCl produced the fastest, safest and accurate analytical results with a recovery of 91–110% and a precision better than 5% in most cases. Very low limits of detection were obtained, below 0.05 μg g−1, for all elements, except for Zn, 2.3 μg g−1. A number of agricultural soil samples irrigated by the Tinishu Akaki River (TAR) and its tributaries, Ethiopia, were analyzed.

  • Determination of trace elements in agricultural soil samples by inductively coupled plasma-mass spectrometry: Microwave Acid Digestion versus aqua regia extraction
    Analytica Chimica Acta, 2005
    Co-Authors: Samuel Melaku, Richard Dams, Luc Moens

    Abstract:

    Microwave Acid Digestion and aqua regia extraction techniques were investigated to obtain a simple, rapid and safe method for the determination of eight trace elements in soil (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn). Soil samples were collected between 6 October and 3 November 2004, air dried, grinded, sieved (

Samuel Melaku – 3rd expert on this subject based on the ideXlab platform

  • determination of trace elements in agricultural soil samples by inductively coupled plasma mass spectrometry microwave Acid Digestion versus aqua regia extraction
    Analytica Chimica Acta, 2005
    Co-Authors: Samuel Melaku, Richard Dams, Luc Moens

    Abstract:

    Microwave Acid Digestion and aqua regia extraction techniques were investigated to obtain a simple, rapid and safe method for the determination of eight trace elements in soil (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn). Soil samples were collected between 6 October and 3 November 2004, air dried, grinded, sieved (<63 μm) and subjected to Digestion. The digests were subsequently analyzed for metal content by inductively coupled plasma-mass spectrometry (ICP-MS). Various combinations and volumes of hydrofluoric, nitric and hydrochloric Acids were evaluated for the microwave Acid Digestion efficiency. Two certified reference materials (CRM 142, light sandy soil, and CRM 143, over fertilized soil) were used in the comparison of these Digestion protocols and good agreement between the two procedures and the certified values was found. The aqua regia microwave Acid Digestion with a mixture of 2 ml of HNO3 and 6 ml of HCl produced the fastest, safest and accurate analytical results with a recovery of 91–110% and a precision better than 5% in most cases. Very low limits of detection were obtained, below 0.05 μg g−1, for all elements, except for Zn, 2.3 μg g−1. A number of agricultural soil samples irrigated by the Tinishu Akaki River (TAR) and its tributaries, Ethiopia, were analyzed.

  • Determination of trace elements in agricultural soil samples by inductively coupled plasma-mass spectrometry: Microwave Acid Digestion versus aqua regia extraction
    Analytica Chimica Acta, 2005
    Co-Authors: Samuel Melaku, Richard Dams, Luc Moens

    Abstract:

    Microwave Acid Digestion and aqua regia extraction techniques were investigated to obtain a simple, rapid and safe method for the determination of eight trace elements in soil (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn). Soil samples were collected between 6 October and 3 November 2004, air dried, grinded, sieved (