Microwave-assisted catalytic combustion for the efficient continuous

Subscriber access provided by UNIV OF NEW ENGLAND ARMIDALE

Remediation and Control Technologies

Microwave-assisted catalytic combustion for the efficient continuous cleaning of VOC-containing air streams Hakan Nigar, Ignacio Julian, Reyes Mallada, and Jesús Santamaría Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.8b00191 • Publication Date (Web): 17 Apr 2018 Downloaded from http://pubs.acs.org on April 17, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 29

Environmental Science & Technology

1

Microwave-assisted catalytic combustion for the

2

efficient continuous cleaning of VOC-containing air

3

streams

4

Hakan Nigar,† Ignacio Julián,† Reyes Mallada,*,†,‡ Jesús Santamaría*,†,‡

5

† Nanoscience Institute of Aragon and Chemical and Environmental Engineering Department,

6

University of Zaragoza, 50018 Zaragoza, Spain

7

‡ Networking Research Centre CIBER-BBN, 28029 Madrid, Spain

8

Adsorption, Catalytic oxidation, Volatile organic compounds, Microwave heating

9

ABSTRACT: A microwave-heated adsorbent-reactor system has been used for the continuous

10

cleaning of air streams containing n-hexane at low concentrations. Both a single catalytic bed

11

(PtY zeolite) and a double (adsorptive DAY zeolite + catalytic PtY zeolite) fixed-bed reactor

12

configurations were studied under dry and humid conditions. The zeolites were selectively

13

heated by short periodic microwave pulses that caused the desorption of n-hexane and its

14

subsequent catalytic combustion. The double bed configuration was attractive because it allowed

15

nearly the same performance with only half of the catalyst load. The operation was especially

16

efficient under realistic humid gas conditions that favored more intense microwave absorption,

17

producing a faster heating of the adsorptive and catalytic beds. Under these conditions,

ACS Paragon Plus Environment

1


Page 2 of 29

18

continuous gas cleaning could be achieved with short (3 min, 30 W) microwave heating pulses

19

every 5 min.

20

INTRODUCTION

21

Among air pollutants, Volatile Organic Compounds, VOCs, are significant contributors to

22

poor air quality in the cities, both indoor and outdoor air. These low vapor pressure pollutants are

23

released to the atmosphere by both biogenic and anthropogenic sources, e.g., vehicles, processes

24

using solvents and industry. In 2014, according to the European Environment Agency, EEA, 8

25

billion tons of VOCs were emitted only in Europe. Although the emissions of many air pollutants

26

have decreased substantially in Europe over the last decades, this is still a major concern due to

27

their participation in atmospheric photochemical reactions and their contribution to ozone

28

formation and potential toxicity.1

29

The indoor emissions of VOCs are of even higher concern since we spend almost 90% of our

30

time in indoor environments such as houses, offices, shops, public buildings, and vehicles. Inside

31

buildings, VOCs are continuously released to indoor air from different sources, i.e., tobacco

32

smoke, cleaning products, furniture (e.g., varnish and glues) and office equipment (e.g., printers

33

and computers).2-4 For large buildings where a substantial proportion of air is recirculated to save

34

energy in air conditioning, the concentration of VOCs can reach high levels in comparison to the

35

outdoor values. In particular, high VOCs concentrations present inside buildings could lead to

36

the so-called “Sick Building Syndrome” a medical condition in which building occupants suffer

37

from some symptoms of illness or feeling unwell gratuitously,5 which can be linked to time spent

38

inside a building.

39

The concentration of VOCs in air can be lowered to acceptable levels using either recovery

40

technologies (condensation, membrane separation, adsorption, absorption) or destruction


2

Page 3 of 29


41

technologies, mainly thermal or catalytic oxidation.6-9 The choice of technology is case-specific

42

and depends not only on the type of pollutant but also on its concentration, the main factor

43

regarding the economics of the VOC removal process.10 Thus, when VOCs concentrations are

44

high, as is often the case of industrial emissions, thermal oxidation at high temperatures, i.e.,

45

1000 – 1600 K,11 can be considered since most or all of the energy required to achieve

46

combustion temperatures can be obtained from VOCs combustion. In addition, the thermal

47

energy of process gases can be recovered either by regenerative or recuperative systems.

48

Regenerative thermal oxidation system is recommended for streams between 2000 and 100,000

49

Nm3/h, and concentration of pollutants in the range 0.3 - 10 g/Nm3. Since a high (>95%) thermal

50

efficiency can be achieved in heat recovery, the consumption of fuel is minimized.12

51

However, for dilute concentrations (6 hours) sample 1.8 ± 0.2 nm (150 particles measured in both cases). Therefore, there is

222

no appreciable change in particle size after microwave heating. TEM results are in accordance

223

with XRD data of non-microwave-heated sample, in which the Pt peak was not distinguishable

224

in XRD diffractogram due to the small size of Pt particles.

225 226

Figure 3. TEM images of a PtY sample a) before and b) after microwave heating (30 W, >6

227

hours), and statistical analysis of the Pt particle size distribution.

228

Nitrogen adsorption isotherms and DFT pore size distributions of NaY and ion-exchanged PtY

229

zeolites are shown in Figure 4. They correspond to a Type I isotherm, which is characteristic of


12

Page 13 of 29


230

microporous materials according to the classification of IUPAC. This technique allows to assess

231

any changes in the porosity of the crystalline structure that could have been produced during the

232

ion exchange and also after several catalytic cycles, see Table 1. Obtained BET surface areas

233

were 948 m2/g zeolite and 909 m2/g zeolite and micropore volumes were 0.36 cm3/g and 0.33

234

cm3/g for NaY and PtY zeolites, respectively. Both surface area and the microporous volume

235

were slightly reduced after the ion-exchange. This could be due to the effect of some Pt

236

aggregates, formed during the ion-exchange process.

237

Table 1. Textural properties of NaY and PtY zeolites BET Surface Area

Total Pore Volume

(m2/g)

(cm3/g)

NaY

948

0.36

PtY, after ion-exchange

909

0.33

PtY, after combustion

810

0.29

Sample

238 239

In Table 1, it could be observed that surface area and pore volume of zeolite were reduced after

240

several (more than 100) catalytic cycles of combustion. This could be to the hydrothermal

241

stability of the zeolite Y, the cubic FAU lattices (12.7 T/nm3) undergo dramatic changes of their

242

framework beginning at 423 K, i.e., at relatively mild conditions. In our case, during the

243

combustion process these temperatures were achieved under humidity conditions. The deep

244

analysis of XRD for the sample after combustion, see Figure 2 zoom in, also showed that there is

245

a slight loss in crystallinity showed by a broadening of the peak at 23.5º. However, these loss of

246

crystallinity and reduced pore size are not significant.


13


Page 14 of 29

247 248

Figure 4. Nitrogen adsorption isotherms of NaY and PtY zeolite before and after catalytic tests,

249

inset: pore size distribution by DFT analysis.

250

The amount of Pt incorporated onto the zeolite catalysts was determined by atomic absorption

251

emission spectroscopy (AAS). Five PtY samples prepared at the same conditions were analyzed

252

after being digested with aqua regia under MW heating. Pt content is 1.53 ± 0.21 wt.%.

253 254

Catalytic bed, cyclic operation: Adsorption followed by catalytic combustion assisted by MW

255

The initial purpose was to study in detail the capacity of the catalytic bed for the combustion of

256

desorbed n-hexane by microwave heating starting from a “cold” bed where n-hexane had been

257

adsorbed during the loading stage before MW activation (see Figure 1 c). The PtY catalyst bed

258

load was 400 mg. The inlet gas flow, 100 mL STP/min, which contains 500 ppm of n-hexane,

259

was fed into the fixed-bed for 5 min. All the n-hexane fed during the adsorption stage remained

260

on the zeolite bed since no breakthrough of hexane was observed during this period (Figure 5),

261

i.e., the total n-hexane load was 2.2 mg/g catalyst. After the predetermined loading period, the


14

Page 15 of 29


262

bed was swept by synthetic air (100 mL STP/min) for 5 min and then the microwave source at 30

263

W input power, was switched on for 10 min.

264

The evolution of n-hexane, carbon dioxide concentrations at the outlet flow and the catalyst

265

bed temperature are presented in Figure 5. After MW activation, the temperature increases

266

sharply accompanied by the combustion of the desorbed pulse of n-hexane. From the evolution

267

of the carbon dioxide peak in Figure 5, it can be concluded that n-hexane combustion takes place

268

in approximately 70 seconds, and no breakthrough of unconverted n-hexane is observed. After

269

10 min of MW irradiation the bed is allowed to cool down and then a new cycle of microwave

270

irradiation takes place while passing N2 as a purge gas to make sure that no adsorbed n-hexane

271

remains on the bed, and indeed Figure 5 shows that the bed has been successfully regenerated in

272

the combustion step since there is no n-hexane detected at the outlet stream. This completes the

273

cycle and after cooling the system is ready for the following cycle. The cycle was repeated three

274

times, and 100% conversion of n-hexane was achieved in each of them under these conditions.

275


15


Page 16 of 29

276

Figure 5. Evolution of n-hexane, carbon dioxide concentration and the catalytic bed temperature

277

at the different stages of the cycle: adsorption, flushing with air and microwave activation

278

(power: 30 W). Conditions: single-component fixed bed; load: 400 mg PtY zeolite, total flow:

279

100 mL/min, 500 ppm n-hexane, 5 min loading time, 0% relative humidity.

280

The temperature evolution presented in Figure 5 corresponds to the measurement of the fiber-

281

optic located at the bottom of the catalytic bed. Due to the fiber-optic sensor temperature

282

limitations, the fiber-optic was manually removed from the bed when the temperature

283

approached its operational limit, and therefore no fiber optic data are available above 533 K.

284

However, the temperature evolution could also be tracked using an infrared (IR) camera, giving

285

temperature readings that correspond to the outer quartz wall. This temperature correlates with

286

the inner temperature of the bed measured with the optical fiber, although the differences can be

287

substantial. Thus, the temperature difference measured at the steady-state in between the quartz

288

wall and the inner part of the bed under MW heating (in the absence of reaction, under a power

289

of 30 W) was around 333 K. Under reaction the gradient is expected to be higher since the

290

combustion of n-hexane is exothermic the heat released adds microwave heating (the adiabatic

291

temperature increment, assuming that all the heat released during n-hexane combustion remained

292

in the catalyst bed, i.e., neglecting the heat losses and the heat carried away by the gas, was

293

estimated around 400 K).

294

Figure 6 a illustrates the transient average surface temperature of the quartz tube, measured by

295

the IR camera, together with the inner bed temperature measured by the optical fiber at the end

296

of the bed, and corresponds to the first cycle of the experiment in Figure 5. The inset shows an

297

enlarged IR image of the outer surface of the quartz tube and the area of interest, occupied by the

298

catalyst, which has been used to calculate the corresponding average surface temperature data.


16

Page 17 of 29


299

The initial sharp temperature increment from 0 to around 75 seconds observed in the curve of the

300

fiber-optic readings corresponds to the heating caused only by microwaves. During this time, n-

301

hexane is desorbed from the bed. Then, above a certain temperature combustion starts and the

302

slope changes abruptly because of the contribution from the exothermic combustion of n-hexane.

303

The same change of slope can be observed with some delay in the IR camera measurements

304

presented in Figure 6 a. The evolution of the thermal images with time starting at 72 seconds,

305

just before the combustion initiation are presented in Figure 6 b. It can be observed that the

306

ignition of n-hexane starts at the top of the fixed-bed, which is expected since the saturated

307

zeolite is on the top part. After ignition, the bed is heated by both, the microwave energy

308

absorbed by the zeolite and the heat produced in the reaction, which is carried downstream by

309

the hot gases exiting the reaction zone. The combustion is completed in a short time (see CO2

310

evolution in Figure 5) and then the temperature (as measured by the IR camera at the external

311

surface) goes through a maximum and starts decreasing. Since the temperature inside the fixed

312

bed above 523 K cannot be measured by a fiber-optic (as the limit temperature approaches the

313

fiber is removed from the bed to avoid damage), the quartz wall temperature was followed

314

instead and is reported in the subsequent experiments.


17


Page 18 of 29

315 316

Figure 6. a) Evolution of temperature at the end of the catalyst bed (measured by optical fiber)

317

and of the average external surface of the quartz wall in the region occupied by the catalyst bed

318

measured by IR camera (the inset shows the IR image of the outer surface of the quartz tube, and

319

the area of interest) b) Thermal IR images of the external quartz tube wall at different times to

320

follow the heating of the bed during the combustion after MW irradiation (MW power 30 W,

321

single catalytic bed; load: 400 mg PtY zeolite, total flow: 100 mL/min, 500 ppm n-hexane, 5 min

322

loading time, 0% relative humidity).

323

Continuous operation in catalytic bed, under periodic microwave pulses

324

Dry feed operation

325

After performing full combustion and regeneration of the bed in cyclic operation, the

326

possibility of continuous operation with cyclic combustion was also investigated. The aim was to


18

Page 19 of 29


327

study opportunities for process intensification by avoiding a separate regeneration stage, i.e., the

328

polluted air stream would be continuously fed to the catalyst bed while microwave pulses would

329

be activated periodically to cause desorption and combustion of the trapped n-hexane. Therefore,

330

the system acts as follows: when the microwave is off the catalyst bed acts as a sorbent and

331

accumulates n-hexane. Under MW heating, n-hexane is rapidly desorbed in a high concentration

332

pulse. Combustion of the desorbed pollutant on the catalytic surface rapidly increases the

333

temperature, giving rise to a hot wave that travels down the catalytic bed (similar to the

334

experiment presented in the previous section). Matching of the heating, desorption, combustion

335

and transport rates is critical here. If the pollutant is desorbed and entrained out of the reactor

336

before the catalyst bed downstream has had time to heat up to a sufficiently high temperature,

337

then combustion will be incomplete and a breakthrough of the pollutant will occur.

338

The experiments were carried out by feeding continuously a stream (100 mL/min) containing

339

400 ppm of n-hexane in dry or humid air to the catalytic bed, while the MW was switched off for

340

different periods of time (5, 10, 15 min), followed by a 10 min period of MW activation. Unlike

341

the experiments in the previous section, the feed of polluted air was not interrupted during MW

342

activation, allowing continuous operation. Table 1 shows the n-hexane loads in the bed, and the

343

conversions achieved following MW activation for different loading (Microwave OFF) times. It

344

can be seen that the conversion decreased from 1 to 0.78 as the adsorption (loading) period

345

increased from 5 to 15 min. Interestingly, the load could be doubled (from 2.2 to 4.4 mg

346

hexane/g of catalyst), and essentially full conversion could still be achieved. A similar behavior

347

was also observed by Roland et al.27 in radio-frequency heated beds when a high loading of

348

toluene was used. The results in Table 1 indicate that there is a limitation of the catalytic capacity

349

to completely remove n-hexane as the hydrocarbon loading increases. This behavior can be


19


Page 20 of 29

350

explained as a consequence of the desorption/combustion dynamics. As the loading time

351

increases, the region of the bed containing adsorbed n-hexane extends further into the reactor.

352

Once microwave power is supplied, the whole bed is heated within seconds, promoting fast n-

353

hexane desorption (n-hexane desorbs at temperatures lower than those required for

354

combustion13). The n-hexane desorbed in regions closer to the end of the bed does not have

355

enough contact time for a complete combustion and a breakthrough of unconverted n-hexane is

356

observed.

357

Table 1. Effect of different n-hexane loading (PtY) on its conversion by catalytic oxidation via

358

microwave heating Microwave OFF Microwave ON Experiment

(Adsorption)

Time (min)

mg n-hexane

(% total cycle)

/g catalyst

5

10 (67%)

2.2

10

10 (50%)

15

10 (40%)

Time (min) 1 2 3 4 5 6

(Desorption+Combustion)

n-hexane loading

xnhexane

1.00 1.00 0.98 4.4 0.98 0.76 6.6 0.78

359 360

Humid feed operation

361

Designing realistic processes for adsorption of VOCs from ambient air necessarily has to

362

address the effect of environmental moisture, often present in concentrations that are orders of

363

magnitude higher than the target VOC. This is especially important when zeolites are used, since


20

Page 21 of 29


364

the hydrophilic nature of most zeolites may lead to a displacement of the organic pollutant by

365

water in the adsorption sites of the zeolite. Furthermore, the addition of water, a well-known

366

MW absorber, is also going to affect the heating behavior and the final temperature increment of

367

the catalyst bed. In the following experiments, the effect of environmental moisture was

368

investigated during continuous operation of a MW-assisted air purification scheme.

369

Figure 7 a presents the average transient temperature profiles at the quartz wall and the carbon

370

dioxide evolution during the combustion in dry and humid conditions. There is a striking

371

difference in the evolution of temperature profiles following MW activation for beds that had

372

been exposed to dry and humid air conditions. It can be seen that, under the same applied MW

373

power, the addition of water results in a faster microwave heating and higher final temperatures.

374

This is because, the water molecules are excellent absorbers of MW irradiation 13 and because of

375

this, a larger fraction of the applied MW power is efficiently absorbed by the humid zeolite bed.

376

Indeed, for the bed exposed to humid air the temperature rise is immediate (after only 18 seconds

377

a hot spot is already visible on the outer wall compared to 75 seconds for the bed exposed to dry

378

air, see Figure 7 c) causing a rapid combustion of the adsorbed hexane (combustion is essentially

379

complete in 1.5 min compared to 2.5 min for the bed exposed to dry air).

380 381


21


Page 22 of 29

382 383

Figure 7. Average transient temperature profiles at quartz wall, and evolution of carbon dioxide

384

concentration and Thermal IR images of the external quartz tube wall in b) humid and c) dry

385

conditions (input power: 30 W, single catalytic bed load: 400 mg, total flow: 100 mL/min, 400

386

ppm n-hexane in air, and 0 (dry) or 50% relative humidity).

387

Given the efficient MW absorption by the bed exposed to humid air, the duration of the MW

388

heating pulses was decreased, first to 5 min and then to 3 min, allowing considerable energy

389

savings compared to the dry air case. Figure 8 a shows that during continuous cleaning these 3

390

min MW pulses were enough to achieve complete combustion of the n-hexane fed continuously

391

to the bed, as there was no n-hexane detected at the outlet. This system was operated

392

continuously for 11 cycles with a stable performance (see Figure S1 a in the supporting

393

information).


22

Page 23 of 29


394 395

Figure 8. n-hexane, carbon dioxide, water and reactor wall temperature evolution during

396

continuous operation in the a) catalytic bed (input power: 30 W, catalytic bed load: 400 mg PtY

397

zeolite, total flow: 100 mL/min-1, 400 ppm n-hexane in air, 50% relative humidity), and b)

398

double bed (input power: 30 W, adsorptive bed load: 200 mg DAY zeolite, catalytic bed load:

399

200 mg PtY zeolite, total flow: 100 m/Lmin, 400 ppm n-hexane in air, 50% relative humidity. In

400

the double bed configuration, the temperatures reported correspond to the average surface

401

temperature of the wall in the catalyst bed.


23


Page 24 of 29

402

Continuous operation in double fixed-bed, under periodic microwave pulses

403

In a previous work,13 it was found that the DAY (Si/Al=40, H+) zeolite has higher n-hexane

404

selectivity in a binary mixture of n-hexane and water than NaY (Si/Al=2.5, Na+) zeolite. Taking

405

this into account, a new concept of double fixed-bed, see Figure 1 d, was investigated in the

406

following experiments. In this double fixed-bed configuration, the upstream half of the PtY

407

catalyst bed was replaced with the hydrophobic DAY zeolite (same weight respect to PtY

408

zeolite) in an attempt to favor n-hexane adsorption in the first half of the bed in the presence of

409

water, while concentrating the catalytic function in the second part of the bed.

410

Figure 8 b shows the results obtained under the most severe conditions, i.e., a double bed

411

configuration (containing half of PtY catalyst compared to Figure 8 a) and a MW activation

412

period of only 3 min. It can be seen that even under these conditions, almost complete

413

combustion of n-hexane is achieved, with only a small amount of unreacted n-hexane detected in

414

each combustion pulse at the outlet of the bed, corresponding roughly to 1% of the adsorbed

415

hexane, i.e., the conversion is still around 99%. This shows that the amount of catalyst can be

416

reduced by 50% provided that pollutant adsorption is concentrated preferentially in the first half

417

of the bed. This system operated stably for 11 cycles, giving high n-hexane conversions higher

418

than 99 % (see Figure S1 b, supporting information).

419

The temperature distribution in this double bed configuration is presented in Figure 9. In the

420

thermal images the areas corresponding to the adsorptive, (DAY zeolite), and catalytic, (PtY

421

zeolite), beds walls were evaluated individually in order to calculate the average temperature of

422

each bed separately. The adsorptive bed started heating before the catalytic bed. Even though the

423

adsorptive bed is more hydrophobic compared to the catalytic bed, it can still adsorb water

424

and being upstream is able to contact first with the water containing feed, adsorbing it

13

,


24

Page 25 of 29


425

preferentially. For the experimental conditions of this test, the combustion start is made visible

426

by the temperature of the wall after 45 seconds, beginning from the top of the catalytic bed, and

427

moving downstream, see Figure 9 b.

428 429

Figure 9. a) Average transient temperature profiles at quartz wall (the inset shows the IR image

430

of the outer surface of the quartz tube, and the area of interests, which are occupied by the

431

adsorptive and catalytic bed, respectively), and b) its corresponding thermal IR images during

432

the combustion (Input power: 30 W, adsorptive bed load: 200 mg DAY zeolite, catalytic bed

433

load: 200 mg PtY zeolite, total flow: 100 mL/min, 400 ppm n-hexane in air, 50% relative

434

humidity).

435

The MW-assisted desorption-combustion scheme presented in this paper constitutes a highly

436

attractive technology for a continuous destruction of pollutants present in humid-air streams at


25


Page 26 of 29

437

low concentrations, where other available technologies may not be feasible because of the energy

438

costs involved.

439 440

Supporting Information

441

The evolution of n-hexane, carbon dioxide, water and temperature during continuous operation

442

in the catalytic bed and double bed and corresponding n-hexane conversions regarding the

443

double bed configuration supplied as Supporting Information in Figure S1 (PDF).

444

Corresponding Author

445

*Phone: (+34) 876761153; e-mail: [email protected]

446

*Phone: (+34) 876555440; e-mail: [email protected]

447

ACKNOWLEDGMENTS

448

Financial support from the European Research Council ERC-Advanced Grant HECTOR

449

Project (ID:267626) is gratefully acknowledged. Hakan Nigar also acknowledges financial

450

support from the Spanish Ministry of Education for the FPU grant (Formación del Profesorado

451

Universitario – FPU12/06864).

452 453 454 455 456 457 458 459 460

REFERENCES 1. Air pollution harms human health and the environment; www.eea.europa.eu/themes/air/intro. 2. Mamaghani, A. H.; Haghighat, F.; Lee, C. S., Photocatalytic oxidation technology for indoor environment air purification: The state-of-the-art. Appl. Catal., B 2017, 203, 247-269. 3. Steinemann, A.; Wargocki, P.; Rismanchi, B., Ten questions concerning green buildings and indoor air quality. Build. Environ. 2017, 112, 351-358. 4. Campagnolo, D.; Saraga, D. E.; Cattaneo, A.; Spinazzè, A.; Mandin, C.; Mabilia, R.; Perreca, E.; Sakellaris, I.; Canha, N.; Mihucz, V. G.; Szigeti, T.; Ventura, G.; Madureira, J.; de


26

Page 27 of 29

461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504


Oliveira Fernandes, E.; de Kluizenaar, Y.; Cornelissen, E.; Hänninen, O.; Carrer, P.; Wolkoff, P.; Cavallo, D. M.; Bartzis, J. G., VOCs and aldehydes source identification in European office buildings - The OFFICAIR study. Build. Environ. 2017, 115, 18-24. 5. Guo, P.; Yokoyama, K.; Piao, F.; Sakai, K.; Khalequzzaman, M.; Kamijima, M.; Nakajima, T.; Kitamura, F., Sick Building Syndrome by Indoor Air Pollution in Dalian, China. Int. J. Environ. Res. Public Health 2013, 10 (4), 1489-1504. 6. Takamitsu, Y.; Yoshida, S.; Kobayashi, W.; Ogawa, H.; Sano, T., Combustion of volatile organic compounds over composite catalyst of Pt/γ-Al 2O 3 and beta zeolite. J. Environ. Sci. Health. A Tox. Hazard. Subst. Environ. Eng. 2013, 48 (7), 667-674. 7. Khan, F. I.; Kr. Ghoshal, A., Removal of Volatile Organic Compounds from polluted air. J. Loss Prev. Process. Ind. 2000, 13 (6), 527-545. 8. Wang, H.; Wang, T.; Yu, M.; Huang, X.; Zhong, J.; Huang, W.; Chen, R., Elaborate control over the morphology and pore structure of porous silicas for VOCs removal with high efficiency and stability. Adsorption 2017, 23 (1), 37-50. 9. Domeño, C.; Rodríguez-Lafuente, Á.; Martos, J.; Bilbao, R.; Nerín, C., VOC Removal and Deodorization of Effluent Gases from an Industrial Plant by Photo-Oxidation, Chemical Oxidation, and Ozonization. Environ. Sci. Technol. 2010, 44 (7), 2585-2591. 10. Hashisho, Z. Microwave-swing adsorption for the capture and recovery, or destruction for a more sustainable use of organic vapors. Ph.D Dissertation, University of Illinois, Urbana, IL, 2007. 11. Smith, R., Chemical Process: Design and Integration. Wiley: 2005. 12. Regenerative thermal oxidation; www.condorchem.com/en/regenerative-thermaloxidation. 13. Nigar, H.; Navascués, N.; de la Iglesia, O.; Mallada, R.; Santamaría, J., Removal of VOCs at trace concentration levels from humid air by Microwave Swing Adsorption, kinetics and proper sorbent selection. Sep. Purif. Technol. 2015, 151, 193-200. 14. Huang, H.; Xu, Y.; Feng, Q.; Leung, D. Y. C., Low temperature catalytic oxidation of volatile organic compounds: a review. Catal. Sci. Technol. 2015, 5 (5), 2649-2669. 15. Morales-Torres, S.; Carrasco-Marín, F.; Pérez-Cadenas, A.; Maldonado-Hódar, F., Coupling Noble Metals and Carbon Supports in the Development of Combustion Catalysts for the Abatement of BTX Compounds in Air Streams. Catalysts 2015, 5 (2), 774. 16. Barakat, T.; Rooke, J. C.; Tidahy, H. L.; Hosseini, M.; Cousin, R.; Lamonier, J. F.; Giraudon, J. M.; De Weireld, G.; Su, B. L.; Siffert, S., Noble-metal-based catalysts supported on zeolites and macro-mesoporous metal oxide supports for the total oxidation of volatile organic compounds. ChemSusChem 2011, 4 (10), 1420-1430. 17. Ordóñez, S.; Bello, L.; Sastre, H.; Rosal, R.; Dı́ez, F. V., Kinetics of the deep oxidation of benzene, toluene, n-hexane and their binary mixtures over a platinum on γ-alumina catalyst. Appl. Catal., B 2002, 38 (2), 139-149. 18. Chen, C.; Wang, X.; Zhang, J.; Bian, C.; Pan, S.; Chen, F.; Meng, X.; Zheng, X.; Gao, X.; Xiao, F.-S., Superior performance in catalytic combustion of toluene over mesoporous ZSM5 zeolite supported platinum catalyst. Catal. Today 2015, 258, Part 1, 190-195. 19. Chen, C.; Wu, Q.; Chen, F.; Zhang, L.; Pan, S.; Bian, C.; Zheng, X.; Meng, X.; Xiao, F. S., Aluminium-rich Beta zeolite-supported platinum nanoparticles for the low-temperature catalytic removal of toluene. J. Mater. Chem. A 2015, 3 (10), 5556-5562.


27


505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538

Page 28 of 29

20. Chen, C.; Wang, X.; Zhang, J.; Pan, S.; Bian, C.; Wang, L.; Chen, F.; Meng, X.; Zheng, X.; Gao, X.; Xiao, F. S., Superior performance in catalytic combustion of toluene over KZSM-5 zeolite supported platinum catalyst. Catal. Lett. 2014, 144 (11), 1851-1859. 21. Navascués, N.; Escuin, M.; Rodas, Y.; Irusta, S.; Mallada, R.; Santamaría, J., Combustion of Volatile Organic Compounds at Trace Concentration Levels in Zeolite-Coated Microreactors. Ind. Eng. Chem. Res. 2010, 49 (15), 6941-6947. 22. Ribeiro, F.; Silva, J. M.; Silva, E.; Vaz, M. F.; Oliveira, F. A. C., Catalytic combustion of toluene on Pt zeolite coated cordierite foams. Catal. Today 2011, 176 (1), 93-96. 23. Luo, H.; Wu, X.-D.; Weng, D.; Liu, S.; Ran, R., A novel insight into enhanced propane combustion performance on PtUSY catalyst. Rare Metals 2017, 36 (1), 1-9. 24. Liu, M.-C.; Hsieh, C.-C.; Lee, J.-F.; Chang, J.-R., Impact of Pt and V2O5 on Ethanol Removal from Moist Air Using Pellet Silica-Bound NaY. Ind. Eng. Chem. Res. 2015, 54 (35), 8678-8689. 25. Liotta, L. F., Catalytic oxidation of volatile organic compounds on supported noble metals. Appl. Catal., B 2010, 100 (3), 403-412. 26. Li, J. H.; Ao, P.; Li, X. Q.; Xu, X. S.; Xu, X. X.; Gao, X.; Yan, X. H., Removal of volatile organic compounds at low temperature by a self-assembled Pt/γ-Al2O3 catalyst. Wuli Huaxue Xuebao/ Acta Physico - Chimica Sinica 2015, 31 (1), 173-180. 27. Roland, U.; Kraus, M.; Holzer, F.; Trommler, U.; Kopinke, F.-D., Selective dielectric heating for efficient adsorptive-catalytic cleaning of contaminated gas streams. Appl. Catal., A 2014, 474 (0), 244-249. 28. Sultana, S.; Vandenbroucke, A.; Leys, C.; De Geyter, N.; Morent, R., Abatement of VOCs with Alternate Adsorption and Plasma-Assisted Regeneration: A Review. Catalysts 2015, 5 (2), 718. 29. Zhao, D.-Z.; Li, X.-S.; Shi, C.; Fan, H.-Y.; Zhu, A.-M., Low-concentration formaldehyde removal from air using a cycled storage–discharge (CSD) plasma catalytic process. Chem. Eng. Sci. 2011, 66 (17), 3922-3929. 30. Nigar, H.; Garcia-Baños, B.; Peñaranda-Foix, F. L.; Catalá-Civera, J. M.; Mallada, R.; Santamaría, J., Amine-functionalized mesoporous silica. A material capable of CO2 adsorption and fast regeneration by microwave heating. AIChE Journal 2015, 62 (2), 547-555. 31. Rouquerol, J.; Llewellyn, P.; Rouquerol, F., Is the BET equation applicable to microporous adsorbents? In Stud. Surf. Sci. Catal., 2006; Vol. 160, pp 49-56. 32. Da-Ming, S., An analysis of the structure of the 13X molecular sieve in ion exchange. Vacuum 1993, 44 (2), 75-78.

539 540 541 542 543


28

Page 29 of 29

544


For Table Contents Only

545


29

Microwave-assisted catalytic combustion for the efficient continuous

Recommend Documents