techniques for seperating and analysing the metal containing nanoparticles in wastewater. these techniques are helpful in recycling process of industrial effluents containing nanowastes.

1. Centre for Nano Science & Technology
Institute of Science and Technology
Jawaharlal Nehru Technological University Hyderabad
Kukatpally, Hyderabad-85, Telangana, India.
E-mail: golla.alekhya92@gmail.com
G. Alekhya, CH. Ashok, K. Venkateswara Rao*, CH. Shilpa Chakra

2. CONTENTS
 Objective
 Introduction
 Prediction of ENM concentrations in environment through PEC modelling .
 Need of analytical techniques.
 Flow-Field- flow fractionation (FlFFF)
 Symmetric FlFFF (SFlFFF)
 Asymmetric FlFFF (AF4)
 Hydrodynamic chromatography (HDC)
 Inductively coupled plasma –mass spectroscopy (ICP-MS)
 Hyphenated techniques
 AF4-ICPMS
 HDC-ICPMS
 Conclusion.

3. OBJECTIVE
 Studies on adverse effects of ENM on environment and human health
increased concern about their fate, behaviour and release into
environment. Hence researchers developed modelling techniques for
quantitative risk assessment of ENM.
 Predicted environmental concentration modelling: overview,
conclusions, limitations are briefly discussed. Thus we conclude
necessity of robust and sensitive analytical techniques for detection and
characterization of ENM in natural matrices.
 Techniques for separation of NPs like FFF and HDC, ICP-MS for
quantification are discussed and finally conclusions are made to justify
my title.

4. Source: Project on emerging nanotechnologies (PEN) report The 2014 PEN report
lists 1628 products having nanomaterials this represents an increase of 24% since 2010.
INTRODUCTION

5. Life-Cycle Perspective :

6. Overview of PEC Modelling
Substance flow analysis
i.e) Flow from products to
STP, WIP, Landfills
Ecotoxicological data like
NOEC for assesment
factor of 1000
( RE & HE Scenario )
PEC
PNEC
Estimated worldwide production
volume
Allocation of product volume to
product categories
Pathways of particle release from
products
Flow coefficients within the
environmental compartments
Risk Quotient =
PEC
PNEC

7. Reference Environment Human
Muller & Nowack,
2008
TiO2 > Ag > CNT
Tervonen et al.,
2009
cdse > Ag > MWCNT > C60 > Ad
D’Brien &
Cummins, 2010
TiO2 > Ag > CeO2
Gottschalk et al.,
2009
Ag > ZnO > TiO2 > CNT = C60
Zuin et al., 2011 QD >> C60 > SWCNT >
CB
Aschberger et al.,
2011
ZnO >> Ag > TiO2 > MWCNT =
C60
AG > MWCNT > C60 >
TiO2
Gottschalk et al.,
2013
Ag>TiO2>ZnO
Relative Risk Rankings for ENM :

8. (Environmental Pollution 185 (2014) 69-76)

9. Limitations of Modelling Techniques
 Fast development of engineered nanomaterials (ENM) production and
applications.
 The availability and quality of published information on fate and
behaviour have increased enormously.
 Uncertainty of input parameters.
 PEC values are calculated based on case studies and scenarios but not
globally considerable.
Hence there is a need for robust methods to quantify the presence of
ENM in environmental samples known as Analytical techniques.

10. Field- Flow Fractionation
Prog Polym Sci, 2009

11. Flow- Field Flow Fractionation Principle :
Source: Analytical and Bioanalytical chemistry (2008), vol 392, pp 1447-1457

12. SFlFFF and AF4
(a) schematic representation of Symmetric (FlFFF) and (b) Asymmetric (AF4) channel structures. (Prog Polym Sci, 2009)

13. Hydrodynamic Chromatography (HDC)
(Source: Dissertation of Ammanda Kimberly Brewer)

14. doi:10.1371/journal.pone.0090559.g001
Retention factor =
𝑡𝑖𝑚𝑒 𝑠𝑝𝑒𝑛𝑡 𝑏𝑦 𝑡ℎ𝑒 𝑠𝑜𝑙𝑢𝑡𝑒 𝑖𝑛 𝑠𝑡𝑎𝑡𝑖𝑜𝑛𝑎𝑟𝑦 𝑝ℎ𝑎𝑠𝑒(𝑡 𝑠)
𝑡𝑖𝑚𝑒 𝑠𝑝𝑒𝑛𝑡 𝑏𝑦 𝑡ℎ𝑒 𝑠𝑜𝑙𝑢𝑡𝑒 𝑖𝑛 𝑚𝑜𝑏𝑖𝑙𝑒 𝑝ℎ𝑎𝑠𝑒(𝑡 𝑚)

15. Inductively Coupled Plasma-Mass
Spectroscopy (ICP-MS)
(www.cco.caltech.edu)

16. AF4-ICPMS for Separation of Ag NPs in STP
Influents

17. Important parameters
Retention: The retarding of analyte zones through their confinement to flow
streamlines with velocities less than the average velocity of the carrier
liquid.
Retention time: The ratio of length of the channel to the velocity of the
cloud molecules distributed exponentially in a parabolic flow profile.
Recovery :
Where S is the signal (peak area) obtained from AF4-ICP-MS/HDC-ICP-MS
and 𝑠 𝑂is the signal (peak) obtained with flow injection into ICP-MS system.

18. HDC-ICPMS for Separation of Ag NPs from STP Sludge

19. CONCLUSION
AF4-ICP-MS is the reliable technique used to separate mixtures of
NPs with significantly great resolution than HDC-ICP-MS.
large recovery ranges are observed for HDC-ICP-MS compared to
AF4-ICP-MS. HDC-ICP-MS provides an additional benefit over
AF4-ICP-MS by proving capable of separating dissolved signal from
NP sample.
Hence HDC-ICP-MS is advantageous over all hyphenated techniques
to characterize nanomaterials analytically in environmental matrices.
Hence this technique may be adopted to remove ENMs in wastewater
treatment from activated sludge, and STP influents. However there is
a need for research on practical implications to establish this
technique for the wastewater treatment.