A Proposal for a New IUPAC Project on theCharacterisation of Porous Solids

Tim Mays

Department of Chemical EngineeringUniversity of BathUnited Kingdom

June 2008

Background

• Current recommendations of the International Union of Pure and Applied Chemistry for the characterisation of porous solids were set out in 1994

• These have since proved to be invaluable to scientists and engineers with interests in porous solids

• However there have been many and varied developments in the area that have been made in the intervening period

• This is a proposal to establish a new IUPAC project on the characterisation of porous solids to update the 1994 recommendations in light of these developments

Outline

• The 1994 IUPAC recommendations for the characterisation of porous solids

• Significant output since 1994

• Scope of characterisation of porous solids

• Some areas to consider for updating the 1994 recommendations

• Process to establish a new IUPAC project

• Concluding remarks

Outline

• The 1994 IUPAC recommendations for the characterisation of porous solids

• Significant output since 1994

• Scope of characterisation of porous solids

• Some areas to consider for updating the 1994 recommendations

• Process to establish a new IUPAC project

• Concluding remarks

Key References

Mays (2007) Studies in Surface Science and Catalysis 160 57

D.H. Everett and F.S. Stone, eds. The Structure and Properties of Porous Materials. Proceedings of the Tenth Symposium of the Colston Research Society, University of Bristol, 1958

Outline

• The 1994 IUPAC recommendations for the characterisation of porous solids

• Significant output since 1994

• Scope of characterisation of porous solids

• Some areas to consider for updating the 1994 recommendations

• Process to establish a new IUPAC project

• Concluding remarks

Proceedings ofCOPS Symposia

COPS-IVBath, 1996

COPS-VHeidelberg, 1999

COPS-VIAlicante, 2002

COPS-VIIAix-en-Provence, 2005

Proceedings of Workshops on the

Characterization of Porous Materials:From Ångstroms to Millimeters

Princeton, NJ, USA

Colloids Surf., A: Physicochemical and Engineering Aspects, 2001, 187 -188

Ibid., 2004, 241 Adv. Colloid Interface Sci., 1998, 76-77

First Workshop1997

Second Workshop2000

Third Workshop2003

Fourth Workshop2006

Ibid., 2007, 300

Alex Neimark

Fundamentals of Adsorption

1995 FOA-5 USA1998 FOA-6 France2001 FOA-7 Japan2004 FOA-8 USA2007 FOA-9 Italy

J. Rouquérol, F. Rouquérol and K. S. W. Sing, Adsorption by Powders and Porous Solids, Elsevier, Amsterdam, 1998

F. Schüth, K. S. W. Sing and J. Weitkamp, eds., Handbook of Porous Solids (Vols. 1-5), Wiley, Weinheim, 2002

Selected Books in the COPS Area

S. Lowell, J. E. Shields, M. A. Thomas and M. Thommes, Characterization of Porous Solids and Powders: Surface Area, Pore Size and Density, Kluwer, Dordrecht, 2004

More Books in the COPS Area

20001998

Project 2006-021-2-100Liquid Intrusion and Alternative Methods for the Characterization of Macroporous Solids

http://www.iupac.org/web/ins/2006-021-2-100[Accessed 5 June 2008]

ObjectiveTo analyse the various liquid intrusion techniques available to-day to assess the pore-size of materials (with special attention to the pores above 50 nm width), together with other alternatives, in order to provide (i) a critical and comparative appraisal and (ii) an appreciation about the ways which should be favoured and developed to solve the issue described hereafter.

Jean Rouquérol

Current IUPAC Project in COPS Area

Outline

• The 1994 IUPAC recommendations for the characterisation of porous solids

• Significant activities since 1994

• Scope of characterisation of porous solids

• Some areas to consider for updating the 1994 recommendations

• Process to establish a new IUPAC project

• Concluding remarks

Scope

solid

solid interfaces

pore

Characterisation involves the study of three main regions:

• Solid – structure, composition, …• Solid interfaces – structure, composition, …• Pores – size, shape, orientation, location, connectivity, tortuosity, …

• Link characteristics with formation and/or processing actual or predicted performance in applications

Outline

• The 1994 IUPAC recommendations for the characterisation of porous solids

• Significant activities since 1994

• Scope of characterisation of porous solids

• Some areas to consider for updating the 1994 recommendations

• Process to establish a new IUPAC project

• Concluding remarks

Areas for Updating

• Definitions, terminology, classification

• Methods

• Materials

P.E. Levitz, In: Handbook of Porous Solids, Vol. 1 (F. Schüth, K.S.W. Sing and J. Weitkamp, eds.), Wiley, Weinheim, 2002, pp. 37-80.

Pore Size – Definition

Not straightforward and will depend on method of measurement.

Pore Size – Classification

"… pore size has, arguably, the greatest or widest influence on the properties (and hence uses) of solids, compared to other parameters such as pore shape. It is therefore unquestionably useful and convenient to use pore size (or pore size distribution) as a means to characterise and compare different porous solids."

Mays (2007) Studies in Surface Science and Catalysis 160 57

Proposed new scheme

mi,r

hhfh,pnN

i

H ii

, 3, 2, 1,

d

lresidua

model

unknownisotherm localdata

Pore Size – DFT and Molecular Simulations

• Local isotherms (kernels of the generalised adsorption isotherm) now commonly obtained using density functional theory or molecular simulations

• Estimates of pore size distributions f(h) = f(w) depend critically on these kernels

Isotherm Classification

0 100 200 300 400 500 6000

1

2

3

4

5

6

7

8

9

10

298 K 313 K 328 K 343 K

nE /

mm

ol g

-1

p / bar

Herbst and Harting (2002), Adsorption 8, 111 CH4 on Norit N1 steam-activated, peat-derived,

extruded carbon pellets

Supercritical Adsorption

Large Pores

Mays, Rigby, et al. (2007). Cement & Concrete Research, 27, 1059

advanced separations

enhanced oil recoverybuilding materials

Catalyst characterisation: 3D micro-computed x-ray tomography image of a sol-gel silica pellet containing entrapped mercury following porosimetry (Rigby, 2004)

Methods

Outline

• The 1994 IUPAC recommendations for the characterisation of porous solids

• Significant activities since 1994

• Scope of characterisation of porous solids

• Some areas to consider for updating the 1994 recommendations

• Process to establish a new IUPAC project

• Concluding remarks

Process to Establish aNew IUPAC Project

• Process established in 2000 http://www.iupac.org/Projects E. D. Becker, Chemistry International, 23(1), 2001

• General criteria Projects should address one of the goals listed in the IUPAC

Strategic Plan Projects should be of international in scope and membership

and be related to the role of chemistry for the needs of mankind

• Key features Ideas → Proposal → Review → Resources → Task Group → Project Duration mormally 12-36 months Funding typically up to US$5,000 mainly for travel, subsistence and

administration costs Consultation / activities / outcomes / dissemination

Outline

• The 1994 IUPAC recommendations for the characterisation of porous solids

• Significant activities since 1994

• Scope of characterisation of porous solids

• Some areas to consider for updating the 1994 recommendations

• Process to establish a new IUPAC project

• Concluding remarks

Concluding remarks

• The time may be right to consider updating the 1994 IUPAC recommendations for the characterisation of porous solids

• Proposal for a new IUPAC project Recommendations for the Characterisation of Porous Solids (Phase 2?) under the Physical and Biophysical Chemistry Division (I)

• Link to Project 2006-021-2-100• Possible start date by end 2008• Could report at CPM-4 in 2009, FOA-10 in 2010 and

finally COPS-9 in 2011

• Next steps: Determine whether idea is supported If so then establish a Task Group and Chair Submit proposal

Acknowledgements

• Organisers and hosts of COPS-9

• Professor Brian McEnaney• Professor Ken Sing• Research colleagues

• Engineering and Physical Sciences Research Council, UK• University of Bath

Nigel Seaton