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Comparative Analysis of Hazardous Air Pollutant Emissions of Casting Materials Measured in Analytical Pyrolysis and Conventional Metal Pouring Emission Tests Yujue Wang,*,†,‡ Fred S. Cannon,§ and Xiangyu Li† †
School of Environment, Tsinghua University, Beijing 100084, China State Key Joint Laboratory of Environmental Simulation and Pollution Control, Beijing 100084, China § Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States ‡
bS Supporting Information ABSTRACT: Demonstration-scale metal pouring emission tests and bench-scale Curie-point pyrolysis emission tests were conducted to identify and quantify the hazardous air pollutant (HAP) emissions of five kinds of casting materials, namely, bituminous coal, cellulose, conventional phenolic urethane binder (PUB), naphthalene-depleted PUB, and a collagen-based binder. For a given casting material, the major HAP species generated in Curie-point pyrolysis were essentially the same as those generated in demonstration-scale metal pouring. The 8 10 HAP species identified in the Curie-point pyrolysis tests comprised 65 98% (by weight) of the total HAP emissions quantified in the demonstration-scale pouring emission tests. Furthermore, with these two protocols, we appraised the relative emission changes that would be associated with (a) replacing conventional PUB with collagen-based binder, (b) replacing conventional PUB with naphthalene-depleted PUB, and (c) replacing bituminous coal with cellulose for making sand molds or cores in the casting process. The relative emission changes associated with the use of alternative casting materials exhibited similar trends for most of the major HAP species in the demonstration-scale pouring and Curie-point pyrolysis emission tests. The results indicated that Curie-point pyrolysis emission test could be employed as a convenient and costeffective screening tool to identify the major HAP species and to compare the relative HAP emission levels for various casting materials.
’ INTRODUCTION Hazardous air pollutant (HAP; defined herein as the 188 compounds that are categorized in Title III: Hazardous Air Pollutants of the 1990 Clean Air Act Amendments) emissions from foundries represent a major environmental concern of the metal casting industry. Previous research has shown that the predominance of HAPs and volatile organic compounds (VOCs) in foundry emissions was generated from the thermal decomposition of mold and core materials during the casting process.1,2 These casting materials include carbonaceous additives (e.g., bituminous coal) and organic resins (e.g., phenolic urethane binders) that are used to make sand molds and cores. To comply with ever-more-stringent air emission regulations, foundries have been seeking alternative raw materials that are more environmentally friendly than the traditional ones, so as to diminish their HAP emissions and operating costs. Many new carbonaceous additives and core binders have been developed (and are being developed), aimed to meet the foundries’ requirement for pollution prevention and quality control.3 7 The need exists for foundries to evaluate these new products as a part of adopting them in full-scale production. r 2011 American Chemical Society
The conventional method to evaluate the emission characteristics of casting materials is stack emission tests that are conducted during metal pouring in demonstration-scale or full-scale foundries. These tests have generated large amounts of valuable data regarding the emission characteristics and levels of many casting materials.5 10 Foundry personnel have been constrained to using stack data to evaluate the relative emission changes associated with the use of alternative casting materials to make sand molds and cores, so as to select lower-emitting casting materials for casting production.5 7 However, metal pouring emission tests are expensive, time-consuming, and labor-intensive. Additionally, the pouring emission results are affected by many site-specific factors such as the casting shape, casting weight, and sand-to-metal ratio used in a specific test. Thus, the emission factors reported for the same casting materials Received: July 5, 2011 Accepted: August 25, 2011 Revised: August 25, 2011 Published: August 25, 2011 8529
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Environmental Science & Technology might vary considerably for a given casting material with these different metal pouring and emission testing protocols.2,11 The inherent site-specificity of metal pouring emission test renders it difficult to compare the emission levels of various materials, because many process parameters that sometimes are difficult to keep constant in metal pouring tests could confound the evaluation results—even within a given foundry. Recently, there has been increasing interest in using analytical pyrolysis techniques to study the pyrolysis mechanisms and emission characteristics of various casting materials. For these appraisals, casting materials are pyrolyzed in either a thermogravimetric analyzer, a Curie-point pyrolyzer, or a pyroprobe under conditions that simulate some key features of metal casting, and then the emissions from analytical pyrolysis are analyzed with proper online and offline instruments.12 17 Compared to metal pouring emission tests, analytical pyrolysis emission tests are easier and faster to conduct, and they cost much less. Furthermore, because the pyrolysis conditions can be strictly controlled, the influence of factors other than the casting materials themselves on the emissions can be minimized and/ or monitored. This offers promise that analytical pyrolysis can be a fast and cost-effective screening tool for comparing emission levels of various materials. For example, these analytical pyrolysis tests could serve as an initial screening tool that can predict relative comparisons of anticipated emission trends during fullscale metal pouring into green sand molds, and over bonded cores. However, virtually no previous studies have thoroughly compared the emission testing results of analytical pyrolysis versus those of actual metal pouring. Thus, the main objective of this study was to compare the HAP emission testing results of metal pouring versus analytical pyrolysis for a variety of casting materials. This comparison has aimed at verifying the usefulness of analytical pyrolysis emission test as an initial screening tool for discerning relative emission trends that could be anticipated at full scale. For example, if HAP emissions were lower for one casting material than for another in bench-scale analytical pyrolysis tests, then an analyst could infer that similar trends would occur during full-scale conditions. Specifically, the HAP emission testing results of Curie-point pyrolysis was compared with those of metal pouring in a demonstration-scale foundry for five kinds of casting materials. These five materials included bituminous coal, cellulose, conventional phenolic urethane binder (PUB), naphthalenedepleted PUB, and collagen-based binder. The bituminous coal and conventional PUB have been commonly used in foundries for many years, and they represent the traditional casting materials. The cellulose, naphthalene-depleted PUB, and collagen-based binder represent alternative materials that have been recently proposed as replacements for conventional casting materials, with the aim of diminishing HAP emissions during the casting process.4 7
’ EXPERIMENTAL SECTION Curie-Point Pyrolysis Emission Tests. Bench-scale Curiepoint pyrolysis emission tests were conducted at Penn State. For these, small amounts of casting material were flash pyrolyzed at 920 °C in a Curie-point pyrolyzer, then the emissions were conveyed in helium through a heated tube (0.5 m in length, 200 °C) into a downstream online GC-FID for analysis. We note that the GC conditions of the Curie-point pyrolysis emission test were set up preferentially for quantifying hydrocarbons with
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6 16 carbon atoms, which were traditionally taken as the surrogate of VOC emissions by U.S. foundries. Smaller HAP compounds with less than 6 carbon atoms (e.g., formaldehyde and acetaldehyde) were not identified and quantified in the Curie-point pyrolysis results presented herein. However, it is noted that in other GC analyses, these smaller HAPs have been identified and quantified with proper adjustments of the GC setting.17 For more details of the Curie-point pyrolysis emission test procedures, see refs 14,16, and 17. For the work reported herein, five casting materials were analyzed for their emission characteristics via the Curie-point pyrolysis emission test. The process parameters were maintained at the same setting for all tests. Thus, the emission test results of various materials could be directly compared against each other to evaluate the relative emission changes associated with the use of different casting materials. The results presented herein represent the averages of three to four replicate analyses; and these replicates were generally within 15% of one another. Demonstration-Scale Metal Pouring Emission Tests. The procedures of demonstration-scale metal pouring emission tests have been detailed in the CERP-Technikon emission testing reports that have become public documents.5 7 These results are presented herein as comparisons to the Curie-point pyrolysis results. Briefly, the test involved pouring metal into stationary molds of several-foot dimensions that hosted the subject casting materials. During the metal pouring, cooling, shake-out, and post-shake-out, the CERP-Technikon team collected continuous air samples from slip streams of the exhaust manifolds that completely surrounded these molds. The HAP emissions were collected and analyzed using U.S. EPA Method 18: the gaseous HAP emissions were collected by adsorption through an activated carbon tube that was mounted on a heated slip stream from the exhaust duct. The sorbed HAPs were then desorbed with carbon disulfide and methanol solvent for analysis with a gas chromatograph-flame ionization detector (GC-FID). The paper herein has evaluated the results of three campaigns of metal pouring emission comparisons. The first, Campaign A, appraised the emissions impact of replacing the conventional PUB with the collagen-based binder in the casting process.6 The second, Campaign B, appraised replacing the conventional PUB with the naphthalene-depleted PUB.7 The third, Campaign C, appraised replacing bituminous coal with cellulose in a green sand mold.5 It is worth noting that different levels of the alternative material are used to replace the traditional material in the sand molds or cores, due to the quality control requirements for producing quality castings. Specifically, for Campaign A, a proportion of 1.0 pounds of collagen-based binder replaced every 1.75 pounds of conventional PUB in the cores.6 Campaign B employed the same proportion of conventional PUB as naphthalene-depleted PUB in the cores.7 In Campaign C, 1.0 pound of cellulose replaced every 4.59 pounds of the bituminous coal in the green sand mold (calculated by the loss on ignition from the green sands).5 HAP emissions were evaluated during these demonstration-scale metal pouring trials. The results herein represent the average of six to nine replicated pouring trials, as reported by the CERP-Technikon team. It is worth noting that these metal pouring emission testing campaigns were specifically designed to evaluate the relative emission levels of the casting materials of interest. To preclude confounding factors that could influence the emissions, the tested casting material was usually the only organic casting material that would generate HAP emissions within the poured 8530
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Table 1. HAPs Identified and Quantified during Demonstration-Scale Metal Pouring and Curie-Point Pyrolysis Emission Testsa Curie-point pyrolysis (mg HAP/g material)
demonstration-scale metal pouring (lb HAP/ton Fe poured) comparison Ab
naph.HAP
conv.
collagen-
depleted
bitum.
PUB
based binder
PUB
coal
comparison Bc
conv. PUB collagen -based conv. naph.-depleted cellulose (1.75)e binder (1.0)e PUB (1.0)e PUB (1.0)e
comparison Cd coal
cellulose
(4.59)e
(1.0)e
1
benzene
6.307
2.243
7.609
1.298
4.022
0.104
0.0188
0.142
0.182
0.145
0.0292
2
toluene
2.715
2.640
3.615
1.150
1.198
0.0229
0.0138
0.0390
0.0493
0.0744
0.0121
3
ethylbenzene
0.177
0.214
0.328
0.0893
0.243
0.000805
0.000916
0.00298
0.0035
0.00835 0.00155
4
xylene
0.766
0.236
0.943
0.788
0.172
0.00866
0.00212
0.0209
0.0249
0.0506
5
aniline
0.783
0.648
1.791
ND
ND
0.0645
ND
0.0273
0.0286
ND
ND
6
phenol
11.921
1.044
13.881
1.125
1.528
0.117
0.00128
0.097
0.121
0.0072
0.00239
7 8
cresol naphthalene
8.794 0.811
0.710 0.203
10.802 0.468
2.212 0.317
1.340 0.695
0.0407 0.028
ND 0.0013
0.0223 0.0142
0.0297 0.0134
0.0138 0.0127
ND 0.00190
9
methylnaphthalene
0.006
0.000461
14.057
0.00935
0.143
1.194
0.661
0.326
0.0673
ND
0.0195
0.00935
10 dimethylnaphthalene 13.554
ND
1.393
0.392
ND
0.0300
ND
0.00295
ND
11 hexane
neg
ND
neg
neg
neg
0.0012
ND
0.00403
0.0047
12 styrene
neg
ND
neg
neg
ND
0.000951
0.00125
0.00134
0.00183
0.00373 0.00101
13 acetaldehyde
ND
ND
ND
ND
ND
0.00678
0.00538
0.00268
0.00219
0.00353 0.0207
14 formaldehyde
ND
ND
ND
ND
ND
0.00101
0.000226
0.00601
0.000474
0.00277 0.00355
15 2-butanone 16 propionaldehyde
ND ND
ND ND
ND ND
ND ND
ND ND
0.00418 0.000366
0.00245 0.000817
0.000437 0.000239
0.000396 0.000147
0.00137 0.00123 0.000661 0.00272
17 biphenyl
ND
ND
ND
ND
ND
0.00174
ND
ND
ND
ND
ND
18 N,N-dimethylaniline
ND
ND
ND
ND
ND
0.0259
ND
ND
ND
ND
ND
19 trimethylnaphthalene neg
ND
ND
neg
ND
0.000175
ND
ND
ND
ND
ND
I: sum of the first 10 HAPs 59.89
8.081
42.02
8.032
9.524
II: sum of all 19 HAPs 100 sum first 10/sum all 19 (%)
0.000971 0.0128
ND 0.00211
0.4839
0.03822
0.3881
0.4618
0.3190
0.05695
0.5262
0.04834
0.4029
0.4715
0.3439
0.08827
91.96
79.06
96.34
97.93
92.77
64.52
a ND: not detected; neg: not quantified due to negligible amounts. b Ref 6. c Ref 7. d Ref 5. e For comparisons A, B, and C; the numbers in parentheses represent the ratios of the first casting binder or organic material to the second.
sand molds or cores. Furthermore, for a given campaign, operational process parameters (e.g., casting shape, weight, pouring temperature, etc.) of the metal pouring were consistently maintained within prescribed ranges, so as to evaluate the relative emission changes associated with the use of alternative casting materials. However, from one campaign to the next, these process parameters were changed. This meant that the results from one campaign could not be quantitatively and directly compared to the results of another campaign (i.e., comparing Campaign A to B or C). Readers are referred to the CERP-Technikon reports5 7 for more details of the three campaigns of emission comparison tests.
’ RESULTS HAP Emissions in Demonstration-Scale Metal Pouring and Curie-Point Pyrolysis Tests. The HAP emissions test results
for both the demonstration-scale metal pouring and Curie-point pyrolysis tests have been summarized in Table 1. The emission factors of demonstration-scale pouring have been reported as pounds of HAPs emitted per ton of metal poured,5 7 whereas the emission factors of Curie-point pyrolysis have been reported as mg HAPs emitted per gram of casting material pyrolyzed.14,16,17 Structural isomers (e.g., m,o,p-xylene) were grouped and reported as a single entity (e.g., xylenes). In total, 19 HAP species were
identified and quantified in the demonstration-scale pouring emission test. In contrast, with the current GC settings, Curiepoint pyrolysis emission tests quantified ten major HAP emissions from the five materials tested herein. These ten HAPs are listed as the first ten HAPs in Table 1; the other HAPs were either unidentified, or not quantified, due to their negligible readings in the Curie-point pyrolysis emission tests.
’ DISCUSSION Previous studies have shown that considerable fractions of HAP emissions are generated at the vicinity of metal-mold/core interface, where casting materials are quickly heated to temperatures of several hundred Celsius degrees up to pouring temperatures. In contrast, casting materials further away from the metalmold/core interface are less thermally affected and release minimal emissions.10,11,18 Based on the results of preliminary Curie-point pyrolysis emission tests and TG-MS tests (see Supporting Information), we perceived that Curie-point pyrolysis conducted herein with the peak temperature of 920 °C could usefully simulate some key features of the fast heating and high temperature pyrolysis conditions at the vicinity of metalmold/core interface. Therefore, we anticipated that the emissions from Curie-point pyrolysis might exhibit some similarity to those observed in the metal pouring emission test. Indeed, as 8531
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Figure 1. Relative abundance of each HAP species normalized to benzene in the emissions of demonstration-scale metal pouring and Curie-point pyrolysis emission tests.
shown in Table 1, for a given casting material, the major HAP species generated in Curie-point pyrolysis were essentially the same as those generated in metal pouring, i.e., the ten HAPs
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identified in Curie-point pyrolysis were also the major HAP species identified in the demonstration-scale metal casting. Specifically, the sum of these ten HAPs accounted for 92 98% of the total HAP emissions quantified in the metal pouring emission tests for the bituminous coal, conventional PUB, and naphthalene-depleted PUB. These ratios were lower for the cellulose (65%) and collagen-based binder (79%) because these two casting materials generated a considerable amount of smaller HAPs, e.g., acetaldehyde and formaldehyde, species that have been listed in the demonstration pouring emissions, but were not included in the ten HAPs quantified in the Curie-point pyrolysis emission test (see Table 1). The similarity in the major HAP species identified in Curie-point pyrolysis and demonstration pouring emissions indicates that the Curie-point pyrolysis emission test could be employed as a convenient and cost-effective screening tool to identify the major HAP species that would be generated from various casting materials during the metal casting process. Yet further, we quantitatively compared the fractional compositions of HAP emissions from specific casting materials during Curie-point pyrolysis versus demonstration-scale metal pouring. It was important to note that the emissions’ absolute values determined via the two protocols were not directly comparable; and indeed, the units were different (mg HAP/g casting material pyrolyzed or lb HAP/ton of iron poured). Therefore, we normalized each of the first ten HAP species in Table 1 relative to the emission of benzene, which was usually the most abundant HAP species in foundry emissions. This was done for each condition, both for the Curie-point pyrolysis and for the demonstration-scale results. Then we compared the relative amounts of the ten HAP species in the Curie-point pyrolysis versus demonstration pouring. As shown in Figure 1a e, for the five casting materials tested herein, the fractional composition of the HAP emissions from Curie-point exhibited some similarity and also some distinctions when compared to the full-scale demonstration results. Specifically, the relative abundances of benzene, toluene, ethylbenzene, and xylenes (BTEX) in the HAP emissions from Curie-point pyrolysis and metal pouring emission tests were very similar (correlations with R2 of 0.8044 0.9555 for the five casting materials, see Supporting Information). In contrast, for the high-boiling HAPs such as phenol, cresols, and polyaromatics, the emission factors determined in Curie-point pyrolysis and metal pouring show no or only slight correlations (R2 of 0.07 0.69, see Supporting Information). The relative abundances of these high boiling HAPs were considerably higher for Curie-point pyrolysis than for the demonstration-scale pouring. The reason for this difference was mostly attributed to the recondensation of the high-boiling HAPs within the sand mold during the metal pouring emission test. Unlike BTEX which have boiling points of 80.1 144 °C and are very easy to volatilize, phenol and cresols, etc., have higher boiling points of 181.7 263 °C and they thus would exhibit a propensity to recondense within the sand molds as they diffused outward from the hot regions of the mold, and then recondensed in the cooler regions.18 20 Also, they could recondense on the particulate matter (such as coal and clay dust) that emitted from the mold.21 Because the demonstration-scale pouring emission tests employed the U.S. EPA method 18 that only measured the gaseous-phase HAPs, the portion of recondensed HAPs could be less represented among the pouring emissions that became released from the mold—i.e., the mold itself effectively served as 8532
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Figure 2. Relative emission changes observed in demonstration-scale metal pouring and Curie-point pyrolysis emission testing; normalized to 1:1 ratio of conventional PUB-to-collagen-based binder.
somewhat of a pollution-capture system for the high-boilers. In contrast, during the Curie-point pyrolysis emission tests, all the generated HAPs were swept by a helium carrier gas via the heated tubing (200 °C, 0.5 m long) to an online downstream GC-FID for analysis; and thus the recondensation of high-boiling HAPs was minimized. For the cellulose, naphthalene-depleted PUB, and collagenbased binder that generated only small amounts of high-boiling HAPs during pyrolysis, the recondensed high-boiling HAPs were negligible and thus would hardly have affected the fractional composition of HAP emissions during metal pouring emission tests. Thus, the HAP emission compositions of the cellulose, naphthalene-depleted PUB, and collagen-based binder during Curie-point pyrolysis and demonstration pouring exhibited more similarity than did the bituminous coal and PUB binders that generated considerable amounts of high-boiling HAPs during pyrolysis. This observation was consistent with the above inference that recondensation of high-boiling HAPs had significant influence on the fractional compositions of HAP emissions during metal pouring emission tests. From this perspective, we perceived that the emission factors determined via Curie-point pyrolysis more reflected the “native potential” of materials to generate HAPs during pyrolysis, whereas the emission factors determined during metal pouring more represented the portions of HAPs that were released as gaseous-phase emissions away from the mold matrix. For the more volatile HAPs, i.e., BTEX compounds that represent the primary pollutants from a foundry,1,2,8,9 there is good correlation between the native potentials determined in Curie-point pyrolysis and the gaseous emissions observed in metal pouring. In contrast, because of the recondensation effects of high-boiling HAPs in the metal pouring emission tests, Curie-point pyrolysis emission tests might somewhat overestimate the relative abundances of high boilers in the gaseous-phase emissions from metal pouring. Further, we discerned that for a given HAP species, the relative emission change trend was similar in Curie-point pyrolysis and metal pouring emission tests, when one casting material was substituted with another casting material. For example, if one casting material generated more benzene than did the substitute in Curie-point pyrolysis, then it would also release more benzene
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Figure 3. Relative emission changes observed in demonstration-scale metal pouring and Curie-point pyrolysis emission testing; normalized to 1:1 ratio of conventional PUB-to-naphthalene-depleted PUB.
Figure 4. Relative emission changes observed in demonstration-scale metal pouring and Curie-point pyrolysis emission testing; normalized to 4.59:1 ratio of bituminous coal-to-cellulose.
emissions than the substitute in metal pouring. This inference has been appraised in the following section. Comparison of Relative Emission Changes Determined in Demonstration-Scale Metal Pouring and Curie-Point Pyrolysis Test. To yet further appraise the value of Curie-point pyrolysis for screening the relative emission changes associated with the use of alternative casting materials, we normalized the results in terms of the percent changes that occurred for each HAP when an alternative casting material was substituted for its conventional counterpart. Specifically, we evaluated the relative emission changes for (a) replacing the conventional PUB with the collagen-based binder, (b) replacing the conventional PUB with the naphthalene-depleted PUB, and (c) replacing the bituminous coal with cellulose. These evaluations were computed for both the Curie-point and demonstration pouring emission tests, and then the relative emission changes observed in the two tests were compared in Figures 2, 3, and 4. As aforementioned, during the demonstration pouring test, the participants replaced the conventional casting materials with 8533
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Environmental Science & Technology different levels of their alternative material counterparts due to quality control and operation cost considerations.5 7 To account for the unequal substitution, we have normalized for these distinctions in the ways described below. For the conventional PUB-to-collagen comparison, the Figure 2 bar graphs for pyrolysis reflect the direct Table 1 column 2 versus column 3 percentage changes. Then the Table 1 Column 6 (PUB demonstration) numbers are divided by 1.75, then compared to Column 7 (collagen demonstration) to discern percent change. Thus, the Figure 2 bar graphs represent a 1:1 proportioning of PUB-tocollagen-based binder. For the Figure 3 comparison of conventional PUB to naphthalene-depleted PUB, the Table 1 values were directly compared without normalization (since they all had 1:1 ratios). For the Figure 4 comparison, the Curie-point pyrolysis cellulose data were divided by 4.59 when comparing them to the Curie-point bituminous coal data. These proportions reflected the same ratio used in the demonstration study; as there was less perceived need for cellulose as for bituminous coal. Figure 2 shows the relative emission changes of the ten HAP emissions when the conventional PUB was replaced by the collagen-based binder during the demonstration pouring versus Curie-point pyrolysis. As shown, the Curie-point pyrolysis emission test usefully predicted the relative emission change trends for nine HAPs that decreased or increased in both emission tests. For toluene, the relative emission changes were quite small, and they exhibited opposite changing trends (but slightly) when comparing the demonstration metal pouring versus Curie-point pyrolysis emission tests. A very significant result was that the collagen-based binder released almost none of the high boilers: naphthalene, methylnaphthalene, or dimethylnaphthalene. These were not released in either the pyrolysis or demonstration trials. Figure 3 shows the relative emission changes caused by replacing the conventional PUB with naphthalene-depleted PUB during demonstration pouring and Curie-point pyrolysis. Again, we observed the same trends of relative emission changes in the two emission tests. Replacing the conventional PUB with naphthalene-depleted PUB decreased the emissions of polyaromatics. However, the emissions of smaller HAP compounds increased for the naphthalene-depleted binder. Figure 4 shows these normalized emission changes associated with using cellulose to replace bituminous coal in the casting process that was evaluated via the Curie-point pyrolysis and demonstration-scale pouring emission tests. The results indicated that when the cellulose was used to replace the bituminous coal in the casting process, the HAP emissions would be considerably diminished. In sum, although the relative emission changing trends predicted in the Curie-point pyrolysis emission test were not quantitatively the same as those observed in the demonstration metal pouring test (and indeed, they were monitored in different units), they showed quite similar trends when changing from one casting material to another for most of the major HAP species. The high-boiling phenolics and polyaromatics appeared more prominently in Curie-point pyrolysis than in full-scale foundry demonstrations, as the high-boilers could recondense within the exterior of the green sand mold. Based on the results presented herein—with the limitations noted—we have perceived that Curie-point pyrolysis emission test is a convenient and costeffective development-phase screening tool for comparing the relative emission trends for substituting various binders and carbonaceous casting materials.
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’ ASSOCIATED CONTENT
bS
Supporting Information. Additional text, tables, and figures. This material is available free of charge via the Internet at http:// pubs.acs.org.
’ AUTHOR INFORMATION Corresponding Author
*E-mail:
[email protected].
’ ACKNOWLEDGMENT This research has been supported by NSF-China project (51008175); a special fund of the State Key Joint Laboratory of Environment Simulation and Pollution Control (09Y01ESPCT); and the US-NSF (BE/MUSES-GOALI 052490). We are deeply grateful for the careful work of CERP personnel in preparing the full-scale data, which is publically posted on the web at http:// www.cerp-us.org/index.htm. We are specifically very grateful to Cliff Glowacki, who worked at CERP while he significantly contributed to preparing this full-scale data. He has discussed this data set and shared his analytical protocols for quality assurance with us. We have gleaned important contributions to this work from our lengthy conversations with him through more than a decade of interaction; and his insights have greatly enhanced this paper. ’ REFERENCES (1) Allen, G. R.; Archibald, J. J.; Keenan, T. Hazardous air pollutants: A challenge to metal casting industry. Am. Foundry Soc. Trans. 1991, 99, 585–593. (2) Technikon Environmental Development Center. CERP Organic HAP Emission Measurements for Iron Foundries and Their Use in Development of an AFS HAP Guidance Document; Technikon, LLC: McClellan, CA, 2006; Technikon 1412-317NA. (3) Ladegourdie, G.; Loechte, K.; Schuh, W. Cold Box 96 the new environmentally friendly cold box binder system. Foundry Trade J. 1997, No. October, 434–436. (4) Eppley, M. C.; Laitar, R. A.; Pahr, E. R.; Roush, D. C.; Tse, R.; Zaretskiy, L. S. Improved phenolic urethane cold box foundry resin system. Am. Foundry Soc. Trans. 2005, 113, 505–510. (5) Technikon Environmental Development Center. The Addition of Cellulose to Molding Sand When Reducing Seacoal for Emission Reduction during Pouring, Cooling and Shakeout; Technikon, LLC: McClellan, CA, 2007; Technikon 1413-319NA. (6) Technikon Environmental Development Center. Hormel Core Test in Aluminum and Hormel Core Test in Iron; Technikon, LLC: McClellan, CA, 2001; Technikon RV 100089 CT and RV 100090CU. (7) Technikon Environmental Development Center. Emission Comparison of Phenolic Urethane Binders with Standard Solvents and NaphthaleneDepleted Solvents; Technikon, LLC: McClellan, CA, 2003; Technikon 1409-125 FB and 1409-117 FC. (8) Glowacki, C. R.; Crandell, G. R.; Cannon, F. S.; Voigt, R. C.; Clobes, J. K.; Furness, J. C.; McComb, B. A.; Knight, S. M. Emissions studies at a test foundry using an advanced oxidation-clear water system. Am. Foundry Soc. Trans. 2003, 111, 579–598. (9) Goudzwaard, J. E.; Kurtti, C. M.; Andrews, J. H.; Cannon, F. S.; Voigt, R. C.; Firebaugh, J. E.; Furness, J. C.; Sipple, D. L. Foundry emissions effects with an advanced oxidation blackwater system. Am. Foundry Soc. Trans. 2003, 111, 1191–1211. (10) Tiedje, N.; Crepaz, R.; Eggert, T.; Bey, N. Emission of organic compounds from mould and core binders used for casting iron, aluminum and bronze in sand moulds. J. Environ. Sci. Health, A 2010, 45, 1866–1876. 8534
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Environmental Science & Technology
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dx.doi.org/10.1021/es2023048 |Environ. Sci. Technol. 2011, 45, 8529–8535
