NanoSorb Sorption to engineered nanomaterials and its impact on the - PowerPoint PPT Presentation

NanoSorb Sorption to engineered nanomaterials and its impact on the bioavailability/toxicity of fossil fuel-derived hydrocarbons to aquatic organisms Andy Booth , Berit Glomstad , Jingfu Liu, Mohai Shen, Dag Altin, Bjørn Munro Jenssen, Florian Zindler RCEES Research Center for Eco- Environmental Sciences Materials and Chemistry 1

Goals  Study how CNT properties affect the adsorption of organic  Understand how carbon nanomaterial physicochemical pollutants properties influence fate in aqueous environments  Investigate how the bioavailability and toxicity of organic  Determine the influence of environmental parameters on pollutants are affected by the presence of CNTs carbon nanomaterials behaviour Phenanthrene Materials and Chemistry 2

Carbon nanomatrials (CNTs)  Fullerenes 'Buckyball  Nanotubes (CNTs) consist clusters' are spherical of rolled up graphite sheets carbon molecules  Different diameters and  Can vary from C 20 to C 100 surface area, number of with C 60 fullerene the most walls common  Different surface chemistry SWCNT MWCNT C 60 Fullerene Materials and Chemistry 3

C 60 aggregation studies C (mmol L -1 ) MW (kD) 1000 100 Na + M f -SRNOM 100 nC 60 30 10 20 MW-dependent stabilization 3 2 Ca 2+ 10 30 M f -SRNOM nC 60 Mg 2+ 100 100 C (mmol L -1 ) Enhanced attachment MW (kD) Effects of molecular weight-dependent physicochemical heterogeneity of natural organic matter on the aggregation of fullerene nanoparticles in mono- and di-valent electrolyte solutions

Molecular Weight Fractions of SRNOM Suwannee River NOM (pristine-SRNOM) 60 Total Mass Recovery 97.0% 57.6% wt% carbon 40 Stepwise separation of SRNOM by Ultrafiltration 20 15.5% 13.0% 7.2% 6.6% 0 0 0 0 0 3 0 0 3 1 < Molecular weight fractions 1 1 - - M 0 3 > - O 0 1 M M 3 M N O O M O R N N O N S R R N R S of SRNOM (M f -SRNOM) S R S S SRNOM type

Preparation and Characterization of nC 60 Dispersion TEM (b) 80 Particle number Gauss Fit of Particle number 60 Particle number 40 20 0 10 20 30 40 50 60 70 Size (nm) DLS Z-average radius Zeta-potential Electrophoretic mobility -3.6 ± 0.1 μmcm /Vs 58.2 ± 0.7 nm 41.2 ± 1.3 mV

Aggregation of nC 60 determined by Time- Resolved DLS Method In the absence of Attachment efficiency ( a ) and Critical Coagulation SRNOMs Concentration (CCC) -1 -1 -1 6.2 mmol L 8.0 mmol L 143 mmol L   d R ( t ) 1    h Attachment efficiency k 1   N d t  t 0 0 0.1     d R t 1   h   1 k N d t     t 0 0 α   0.01   d R t W k 1   h fast   NaCl   N d t  t , fast 0 fast 0 CaCl 2 1E-3 MgCl 2 1 10 100 1000 -1 ) Electrolyte concentration (mmol L

Effect of M f -SRNOM on nC 60 Aggregation 1. In mono-valent electrolyte (NaCl) (a) (b) -1 ; CCC=167 mmol L 1 1 Attachment efficiency Attachment efficiency  =0.41 -1 ; CCC=205 mmol L -1 ;  =0.084 CCC=234 mmol L  =0.49 0.1 0.1 -1 ; CCC=163 mmol L  =0.60 -1 ;  =0.017 CCC=522 mmol L -1 ; CCC=152 mmol L  =0.57 0.01 0.01 no SRNOM no SRNOM SRNOM10-30 pristine-SRNOM SRNOM3-10 SRNOM>100 SRNOM<3 SRNOM30-100 1E-3 1E-3 100 1000 100 1000 -1 ) -1 ) NaCl concentration (mmol L NaCl concentration (mmol L MW of M f -SRNOM , the stabilization of nC 60

Effect of M f -SRNOM on nC 60 Aggregation 2. In di-valent electrolytes MgCl 2 CaCl 2 (a) (a) -1 ; -1 ;  =0.35 CCC=9.0 mmol L CCC=16.3 mmol L 1 1  =0.50 Attachment efficiency Attachment efficiency -1 ; CCC=11.2 mmol L  =0.78 -1 ; CCC=9.4 mmol L  =0.57 -1 ; CCC=25.3 mmol L 0.1 0.1 -1 ; CCC=7.6 mmol L  =0.31  =0.71 no SRNOM no SRNOM pristine-SRNOM LOW electrolyte concentration: pristine-SRNOM SRNOM>100 SRNOM>100 SRNOM30-100 SRNOM30-100 MW of M f -SRNOMs , Stabilization of nC 60 . (b) (b) 0.01 0.01 10 100 10 100 1 1 Attachment efficiency Attachment efficiency -1 ; CCC=10.1 mmol L -1 ; CCC=8.2 mmol L TEM  =0.78  =0.71 -1 ; CCC=9.1 mmol L -1 ; CCC=7.5 mmol L evidence  =0.82 HIGH electrolyte concentration & HIGH MW  =0.64 0.1 0.1 -1 ; -1 ; CCC=7.3 mmol L CCC=6.3 mmol L M f -SRNOMs:  =0.80  =0.79 no SRNOM no SRNOM SRNOM10-30 Enhanced Attachment of nC 60 SRNOM10-30 SRNOM3-10 SRNOM3-10 SRNOM<3 (through Cation-bridges between NOM SRNOM<3 0.01 0.01 10 100 10 100 molecule and nC 60 ) -1 ) -1 ) CaCl 2 concentration (mmol L MgCl 2 concentration (mmol L

CNT characterization  Characterization of CNTs is important to understand the influence of chemical and physical parameters on CNT fate and adsorption behaviour a Measured from TEM images b Given by manufacturer c Calculated by the BET method d Obtained from XPS e Measured on CNTs dispersed in NOM solution Materials and Chemistry 10

CNT fate in the environment  CNT dispersion and stability in aqueous phase depend on their chemical and physical properties  And on environmental factors – natural organic matter (NOM) 1 0 0 8 % C N T s re m a in in g C o n c e n tra tio n (m g /L ) in d is p e rs io n 6 4 5 0 2 0 S W C N T M W C N T -2 M W C N T -3 M W C N T -O H M W C N T -C O O H 0 0 d a y s 3 d a y s 5 d a y s 7 d a y s 1 0 d a y s 1 4 d a y s Stability of CNT dispersions over time CNT dispersion concentration in algal S W C N T M W C N T -2 M W C N T -3 media (TG201) containing NOM after M W C N T -O H M W C N T -C O O H sonication and 24 h settling Materials and Chemistry 11

Phenanthrene adsorption by CNTs  Adsorption capacity 1 0 9  Increasing with increased surface area 1 0 8  Decreasing with increased surface C C N T (µ g /k g ) oxygen content 1 0 7 S W C N T M W C N T -1 5 M W C N T -3 0 1 0 6 M W C N T -O H M W C N T -C O O H 1 1 0 1 0 0 1 0 0 0 C w [µ g /L ] Adsorption isotherms of phenanthrene by CNTs. Dotted lines represent fitting of the Dubinin-Astakhov adsorption model to the experimental data. Materials and Chemistry 12

CNT effect on phenanthrene toxicity to algae  Significant reduction in phenanthrene toxicity only seen in the presence of SWCNT  Based on measured concentrations of freely dissolved phenanthrene an increase in toxicity observed for all CNTs 5 0 0 6 0 0 E C 5 0 ,m e a s u re d (µg /L ) P henanthrene only E C 5 0 ,to ta l (µg /L ) 5 5 0 4 5 0 S W C N T M W C N T -1 5 5 0 0 4 0 0 M W C N T -3 0 4 5 0 M W C N T -O H 3 5 0 M W C N T -C O O H 4 0 0 3 0 0 3 5 0 2 5 0 3 0 0 y T 5 0 H H y T 5 0 H H l 1 3 l N O O 1 3 n N O O - - n - - o C T T - O o C T T - O T T N N W N N e C W N e C N n C C - S n C C - C S T C T e W W e W W r W N r W N h M M C h M M C M t M t n W n W a a M n M n e e h h P P Pseudokirchneriella Phenanthrene adsorbed to CNTs contribute to toxicity – subcapitata still partly bioavailable Materials and Chemistry 13

CNT interaction with algae  Contribution to toxicity by adsorbed phenanthrene might be due to the direct contact between CNTs and algae attached to CNT aggregates  A slight reduction in algal growth rate was seen in the presence of MWCNT-COOH, probably due to shading by the dark coloured dispersion 1 .6 A v e ra g e g ro w th ra te 100 µm 1 .5 1 .4 T 2 3 H H N - - T T O O C N N - O T W C C C N S W W - C T M M W N C M W M Average growth rate in CNT dispersions compared Microscopy image of P. subcapitata attached to to control (TG201-NOM; dotted line). Error bars and MWCNT-15 (Photo: Dag Altin, Biotrix). shaded area represent standard deviations Materials and Chemistry 14

CNT uptake by Daphnia magna  Microscopic imaging showed ingestion of all CNT types by D. magna No feeding Fed algae 48 h exposure only 48 h exposure MWCNT-2 SWCNT 48 h exposure 48 h exposure MWCNT-3 MWCNT-OH MWCNT- 48 h exposure 48 h exposure COOH Light microscopy images of 5-6 d old daphnids 48 h exposure (x40 magnification). exposed to the 5 CNT types. Materials and Chemistry 15

CNT effect on phenanthrene toxicity to Daphnia magna  CNT SSA and surface chemistry appear important for their effect on Phen toxicity to D. magna.  Free phenanthrene does not account for the observed toxicity P henanthrene O nly (E C 5 0 = 335.4 µ g/L ) P h e n a n th re n e O n ly (E C 50 = 3 2 4 .9 µ g/L ) 100 S W C N T (E C 5 0 = 423.2 µ g/L ) S W C N T (E C 50 = 2 5 7 .5 µ g/L ) 100 Im m obilised D aphnids [% ] M W C N T -2 (E C 5 0 = 347.8 µ g/L ) M W C N T -2 (E C 50 = 2 2 2 .1 µ g/L ) Im m obilised D aphnids [% ] M W C N T -3 (E C 5 0 = 417.9 µ g/L ) M W C N T -3 (E C 50 = 2 2 7 .9 µ g/L ) M W C N T -O H (E C 5 0 = 347.2 µ g/L ) M W C N T -O H (E C 50 = 2 5 0 .0 µ g/L ) M W C N T -C O O H (E C 5 0 = 369.0 µ g/L ) M W C N T -C O O H (E C 50 = 2 5 1 .3 µ g/L ) 50 50 0 0 50 100 300 700 50 100 300 700 C f r e e [µ g un bou nd p henan threne L - 1 ] C n o m in a l [µ g phenanthrene L - 1 ] Indicates a large proportion of Phen adsorbed to CNTs is bioavailable to D. magna through ingestion Materials and Chemistry 16