Modeling and experimental studies on ozone absorption into phenolic

Subscriber access provided by UNIV AUTONOMA DE COAHUILA UADEC

Kinetics, Catalysis, and Reaction Engineering

Modeling and experimental studies on ozone absorption into phenolic solution in a Rotating Packed Bed Dan Wang, Taoran Liu, Lei Ma, Feng Wang, and Lei Shao Ind. Eng. Chem. Res., Just Accepted Manuscript • Publication Date (Web): 09 Apr 2019 Downloaded from http://pubs.acs.org on April 9, 2019

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 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Industrial & Engineering Chemistry Research

Modeling and experimental studies on ozone absorption into phenolic solution in a Rotating Packed Bed Dan Wanga,b, Taoran Liua,b, Lei Mac, Feng Wangc, Lei Shaoa,b,* a

State Key Laboratory of Organic–Inorganic Composites, Beijing University of

Chemical Technology, Beijing 100029, China. b

Research Center of the Ministry of Education for High Gravity Engineering and

Technology, Beijing University of Chemical Technology, Beijing 100029, China. c

Solvay (China) Co., Ltd., Minhang Industrial Zone, Shanghai 201108, China.

* Corresponding author. Tel.: +86 10 64421706. E-mail: [email protected]

1

ACS Paragon Plus Environment

Industrial & Engineering Chemistry Research 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Abstract graphic

2


Page 2 of 32

Page 3 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Abstract

Ozonation in rotating packed bed (RPB) is a promising method to treat organic pollutants in wastewater. Mass transfer efficiency of ozone in RPB is of importance to the application of this method. In this work, an overall volumetric mass-transfer coefficient (KGa) model of ozone absorption into organic solution accompanied by an irreversible pseudo-first-order reaction in an RPB was established. The mass transfer processes in both the packing and cavity zones in the RPB were considered for modeling KGa. The predicted and experimental KGa agreed well with the deviations within 10% and 15% for hydroquinone solution and phenol solution respectively, suggesting that this model has good predictability for the mass transfer process of ozone absorption into organic solutions with different reaction rates in RPB. It is also noted that ozone absorption percentage in phenol solution was 40% - 60%, but a much higher ozone absorption percentage in hydroquinone solution of 80% - 95% was achieved due to a higher KGa. These results can be used to predict the mass transfer performance of ozone in organic wastewater treatment in RPBs.

Key words: ozone; rotating packed bed; mass transfer; modeling; phenolic solution

3



Nomenclature a

total specific area of mass transfer (m2·m-3)

ad1

specific area of droplets in the packing zone (m2·m-3)

ad2

specific area of droplets in the cavity zone (m2·m-3)

af

specific area of the packing in the RPB (m2·m-3)

c0

ozone concentration at the gas-liquid interface (mol·m-3)

ci

inlet ozone concentration (mg·L-1)

cout

outlet ozone concentration (mg·L-1)

𝑐O3

ozone concentration in liquid film (mol·m-3)

cOrganic

concentration of organic compound in liquid film (mol·m-3)

cOrganic-0

initial concentration of organic compound in liquid bulk (mol·m-3)

cOrganic-t

concentration of organic compound in liquid bulk after treatment (mol·m-3)

di

average droplet diameter in the packing zone (m)

do

average droplet diameter in the cavity zone (m)

dp

cylinder equivalent diameter of the packing (m), dp=6(1-ε)/af

D

diffusivity of ozone in water (m2·s-1)

DG

diffusivity of ozone in gas (m2·s-1)

G

gas mass flux (kg·m-2·s-1)

Gi

gas flow rate (L·h-1)

H

Henry’s constant of ozone in water (Pa·m3·mol-1)

k1

intrinsic reaction rate constant (L·mol-1·s-1)

kapp

pseudo-first-order rate constant (s-1)

kG

mass-transfer coefficient of ozone in gas film (mol·Pa-1·m-2·s-1)

kL

mass-transfer coefficient of ozone in liquid film (m·s-1)

kL1

mass-transfer coefficient of ozone in the liquid film of filmy liquid (m·s-1)

kL2

mass-transfer coefficient of ozone in the liquid film of droplet (m·s-1)

kLd1

mass-transfer coefficient of ozone in the liquid film of droplet in the packing zone (m·s-1)

kLd2

mass-transfer coefficient of ozone in the liquid film of droplet in the cavity 4


Page 4 of 32

Page 5 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


zone (m·s-1) KG a

overall volumetric mass-transfer coefficient (mol·Pa-1·m-3·s-1)

L

liquid flow rate (L·h-1)

n

layer of the packing in the RPB (n = 20 in this study)

̅̅̅̅̅ N O3

time-averaged mass transfer rate of ozone per unit interfacial area (mol·m-2·s-1)

q

dimensionless initial velocity of liquid

QG

volumetric flow rate of ozone (m3·s-1)

QL

volumetric flow rate of liquid (m3·s-1)

r

radial coordinate of droplet (m)

rc

outer radius of the cavity zone (m)

rd

radius of droplet (m)

ri

inner radius of the packing zone (m)

ro

outer radius of the packing zone (m)

R

molar gas constant, R = 8.314 J·mol-1·K-1

R1

reaction rate of ozone with organic compound (mol·L-1·s-1)

Ra

geometrical mean radius of the packing (m)

RO

rotation speed of the RPB (rpm)

Re

Reynolds number, 𝑅𝑒 =

RO3

mass transfer rate at the gas-liquid interface (mol·m-2·s-1)

s

complex variable

S

renewal frequency of filmy liquid (s-1)

t

time coordinate (s)

t̅

mean lifetime of filmy liquid (s)

T

temperature (K)

uo

initial velocity of liquid (m·s-1)

up

average radial velocity of filmy liquid in the packing zone (m·s-1)

ur

average radial velocity of droplet in the cavity zone (m·s-1)

We

Weber number, We =

𝜌𝜔𝑟o2 𝜇

ρω2 r3o σ

5



x

liquid film thickness of filmy liquid from the gas-liquid interface (m)

yi

mole fraction of ozone in inlet gas of the RPB

yo

mole fraction of ozone in outlet gas of the RPB

z

quadratic mean of axial length of the packing and cavity zones (m)

Z

ratio of consumed ozone to degraded organic compound (mol·mol-1)

zi

axial length of the packing zone (m)

zo

axial length of the cavity zone (m)

Greek letters βa

ozone absorption percentage (%)

βd

organic compound degradation percentage (%)

δ

average thickness of liquid film (m)

ε

voidage of the packing (%)

εL

liquid hold-up in the RPB (m3·m-3)

μ

water viscosity (pa·s)

μG

gaseous ozone viscosity (pa·s)

ρ

water density (kg·m-3)

ρG

gaseous ozone density (kg·m-3)

σ

surface tension (N·m-1)

6


Page 6 of 32

Page 7 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1. Introduction Ozone is a strong oxidant and has been widely used for disinfection of drinking water and advanced treatment of sewage. 1-3 Ozone can function directly or decompose into free radicals, mainly hydroxyl radicals, in the ozonation processes. Many kinds of organic compounds, especially some aromatic compounds, can react with ozone quickly. For example, the reaction rate constant of ozone and phenol is 1.3×103 L·mol1

·s-1 under acidic condition, and the constant is up to 1.4×109 L·mol-1·s-1 for anionic

phenol. Eino Mvula et al. found that the reaction rate constants of hydroquinone and ozone at pH of 3 and 7 are 1.8×106 L·mol-1·s-1 and 2.3×106 L·mol-1·s-1, respectively.4 Compared with hydroquinone, catechol has a relatively slow rate constant of 5.2×105 L·mol-1·s-1 at pH=7.4 Generally, macromolecules such as soluble aromatic compounds in wastewater may not be biodegraded directly due to their toxicity and lack of reactive sites.5 Nevertheless, these organic compounds can be oxidized into biodegradable substances by ozone.6 Therefore, ozonation does not only degrade organic compounds, reduce toxicity and remove COD (chemical oxygen demand), but also improve the biodegradability, which means an increase in BOD5/COD (biochemical oxygen demand after 5 days/chemical oxygen demand) value.7-11 The absorption efficiency of ozone is very important in the ozonation processes because ozone has a negative impact on humans, animals and plants, and the unutilized ozone has to be destructed. Owing to the low solubility of ozone in liquid, it is difficult to absorb ozone effectively in reactors like bubble columns or stirred cell reactors.12 Therefore, process intensification devices that can improve the absorption and utilization efficiency of ozone are desirable. Rotating packed bed (RPB) is a typical process intensification device, which was proposed by Ramshaw and Mallinson in 1976.13 In an RPB, centrifugal force is created to simulate a high-gravity environment for intensifying the contact between gas and liquid. Liquid is introduced into the rotor of RPB and is split into droplets, films and threads, leading to a significant increase of the specific surface area of liquid and improvement of gas-liquid mass transfer.14 RPBs have thus been used to enhance the 7



Page 8 of 32

absorption of CO2,15-18 H2S19 and SO2.20 Some studies focused on combining the ozone-based advanced oxidation processes (AOPs) and RPB to treat organic wastewater. The results show that in addition to the improvement of removal efficiency of organic pollutants and COD, the biodegradability is enhanced markedly.21-26 Although these results demonstrate that RPB can effectively boost the efficiency of organic wastewater treatment by the ozonebased AOPs, few studies have paid attention to the effect of RPB on the mass transfer of ozone, which is of importance to the application of ozonation. Therefore, modeling the mass transfer behavior of ozone absorption into aqueous solution in RPB can provide a theoretical basis for the treatment of organic wastewater by ozonation in RPB. In this study, predicted and experimental mass transfer coefficients of ozone in an RPB were investigated. Hydroquinone and phenol solutions were studied because they are representative compounds in phenolic wastewater and the reaction rate constants of ozone with hydroquinone and phenol have a big difference. In addition, the influence of different operating parameters on the mass transfer coefficient and ozone absorption efficiency in these two organic solutions was explored.

2. Model development 2.1 Reactions of ozone in organic solution The reactions of ozone with organic compounds occur when ozone is absorbed into an organic solution. The reactions are as follows: Ozone + Organics compounds → Products

(1)

These reactions are usually second order (i.e. first order with respect to each reactant) and irreversible.27 The concentration of organic compounds in industrial effluents is generally high and excess compared to ozone. Therefore, the reactions of ozone with organic compounds are usually described as pseudo-first-order reactions that can be expressed as follows, R1 =k1 ×cO3 ×cOrganic

(2)

R1 =kapp ×cO3

(3) 8


Page 9 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


kapp =k1 ×corganic

(4)

2.2 Gas-liquid mass transfer of ozone accompanied by irreversible reactions 2.2.1

Assumption

(1) Liquid exists as droplets and films in the packing zone and only as droplets in the cavity zone of RPB.14, 28 (2) Specific area of the packing in RPB is considered to be the specific area of filmy liquid in the packing zone.18 (3) The liquid film of filmy liquid, defined as a thin boundary layer in the filmy liquid at the gas-liquid interface, is renewed once every time when it passes through one layer of the packing in the RPB. The average life of the film in each layer, which is determined by liquid residence time in the packing and the number of packing layers, is the same.29 (4) In this study, the pH of the organic solution was adjusted to 3, and only the direct oxidation by ozone is considered. (5) The reaction is regarded as a pseudo-first-order reaction and the concentration of organic compound is assumed to be constant in the liquid film. 2.2.2

Model establishment

Ozone is absorbed from gas to liquid through the gas film and liquid film. According to the study of Onda et al.,30 the mass transfer coefficient in the gas film in an RPB can be expressed as follows, kG = 2*10-3 *(

DG af RT

G

μG

f G

G DG

)( a μ )0.7 ( ρ

0.33

)

(af dp )-2

(5)

The mass transfer coefficient in the liquid side is composed of those in the filmy liquid and droplets. As for the liquid film of filmy liquid, the partial differential equation on mass for describing the diffusion of ozone into liquid, which is accompanied by a pseudo-first-order irreversible chemical reaction, can be expressed as, ∂cO3 ∂t

= DO3

∂2 cO3 ∂x2

- kapp cO3

cO3 (x,0) = 0

(6)

B.C. cO3 (0, t) = c0 ，cO3 (δ, t) = 0 9



Page 10 of 32

where c0 is determined by (pO )/(HO ), and is the concentration of ozone at the gas3

3

liquid interface. An ordinary differential equation can be obtained by the Laplace transform. d2 u kapp +s u=0 dx2 D c0

u(0,t) =

,u(δ,t) = 0

s

(7)

The solution to equation (7) is, u=

c0

exp (-x√

s

kapp +s D

)

(8)

By the inverse Laplace transform, an analytical expression for the concentration distribution of ozone with respect to time and penetration depth in liquid film can be written as, cO3 =

c0 2

exp (-x√

kapp D

x

c

kapp

) erfc (2√Dt -√kapp t) + 20 exp (-x√

D

x

) erfc (2√Dt +√kapp t) (9)

The mass transfer rate at the gas-liquid interface is obtained from Fick’s first law. RO3 = -D

∂cO3 ∂x

(x=0) = c0 √kapp D -

c0 √D exp(-kapp t) √πt

(10)

The filmy liquid is renewed when passing through each packing layer, and the renewal frequency is expressed as, 𝑆 = 𝑢p 𝑟

𝑛

(11)

o −𝑟i

The average liquid velocity in the packing zone is given as,31 up =0.02107L0.2279 (ωRa )0.5448

(12)

The mean lifetime of filmy liquid is defined as, t̅ =

1

(13)

S

It is assumed that t ̅ at each packing layer is the same, thus the Higbie distribution function of lifetime of filmy liquid is expressed as, 1

φ(t)= t̅

0 ≤ 𝑡 ≤ 𝑡̅

(14)

The mass transfer coefficient of the liquid film in filmy liquid can be obtained 10


Page 11 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


from the following equation (15), and the mass transfer rate of ozone in the liquid film on each layer of the packing can be expressed by equation (16). ̅̅̅̅̅ NO3 = kL1 c0

(15)

t̅ ̅̅̅̅̅ NO3 = kL1 c0 = ∫0 RO3 φ(t)dt = c0 √kapp D +

c0 √kapp Derfc(√kapp t-̅ 1) kapp t ̅

(16)

The mass transfer coefficient of the liquid film in filmy liquid can be deduced as, kL1 = √kapp D +

√kapp Derfc(√kapp t-̅ 1)

(17)

kapp t ̅

As for a droplet, the diffusion of ozone into liquid accompanied by a pseudo-firstorder irreversible chemical reaction can also be described by the partial differential equation on mass as follows, ∂cO3 DO3 ∂ 2 ∂c = 2 (r ) - kapp cO3 ∂t r ∂r ∂r cO3 (r,0) = 0

(18)

B.C. cO3 (0, t) = 0，cO3 (rd , t) = c0 The following equation can be deduced from equation (18). ∂cO3

2D ∂cO3

=

∂t

r

∂r

+D

∂2 cO3 ∂r2

- kapp cO3

(19)

And the following ordinary differential equation is obtained by the Laplace transform. d2 u dr2

+

2 du r dr

-

kapp +s D

u=0

(20)

Using α to represent (u×r), the following equations can be obtained. dα dr d2 α dr2

du

= r dr + u d2 u

dr2

d2 α dr2

du

= r dr2 + 2 dr

1 d2 α r

(21)

=

=

d2 u dr2

kapp +s D

+

(22)

2 du

(23)

r dr

α

(24)

And the solution to α is, kapp +s -r√

α = u × r = C1 e

D

kapp +s

r√

+C2 e

D

(25) 11



Page 12 of 32

By the inverse Laplace transform, equation (25) is transformed into, C1

cO3 × r = r 2√Dt

2

kapp

exp (r√

+√kapp t) +

√kapp t) +

C2 2

C2 2

D

r

) erfc (- 2√Dt -√kapp t) + kapp

exp (-r√ kapp

exp (r√

D

D

C1 2

kapp

exp (-r√

D

) erfc (-

r

) erfc (2√Dt r

) erfc (2√Dt +√kapp t)

(26)

Equation (26) is solved by using the boundary conditions in equation (18) to obtain the expression of cO3 as follows, cO3 = r 2√Dt

C1

exp (r√ 2r

kapp D

r

kapp

C

+√kapp t) + 2r2 exp (-r√ kapp

C

2 √kapp t) + 2r exp (r√

kapp

C

) erfc (- 2√Dt -√kapp t) + 2r1 exp (-r√

D

D

D

) erfc (-

r

) erfc (2√Dt r

) erfc (2√Dt +√kapp t)

(27)

To simplify the expression, β is defined as, kapp

𝛽 = exp (rd √

D

kapp

r

d ) erf (2√Dt +√kapp t) + exp (-rd √

D

r

d ) erf (2√Dt -√kapp t)

(28)

C1 and C2 are defined as, C1 =

c0 rd

(29)

β

C2 = - C1 = -

c0 r d

(30)

β

According to Fick’s law, the mass transfer rate at the gas-liquid interface is determined by the following equation (31). It is assumed that the irreversible reaction occurs in liquid film, in which ozone is completely consumed, thus the ozone concentration in liquid bulk is zero, and the mass transfer coefficient in droplets (kL2 ) can be expressed as and calculated by expressed as equation (32). RO3 = D

∂cO3 ∂x

(r = rd ) = kL2 (c0 -0)

(31)

12


Page 13 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


kL2 =

D β

kapp

√

D

kapp

[exp (rd √

D

kapp

D

√kapp t)] + β√πDt [exp (rd √ D rd

kapp

r

d ) erf (2√Dt +√kapp t) - exp (-rd √

D

D

kapp

r

d -( 2√Dt +√kapp t)2 ) + exp (-r0 √

r

d ) erf (2√Dt -

D

r

d -( 2√Dt -√kapp t)2 )] -

D

=√kapp D -

(32)

rd

Equation (32) can be used to express the mass transfer coefficients of droplets in both the packing and cavity zones in an RPB. Nonetheless, the expressions of the droplet radius in the two zones are different. Therefore, kLa in the packing and cavity zones should be discussed separately. According to the study of,31 droplet radius and specific area in the packing zone can be calculated by the following equation. σ

di = 0.7284( ω2 R ρ )0.5

(33)

a

ad1 =

6(εL-δaf )

(34)

di

The expression of droplet radius in the cavity zone is given as.14 do ro

r

= 0.042We-0.272 Re0.068 q0.098 ( ro )-0.776

q=

r

uo

(35) (36)

ωR

The specific area of droplets in the cavity zone can be obtained by the following equation. ad2 =

6εL

(37)

do

The overall volumetric mass-transfer coefficient (KGa) in RPB can be expressed as, 1 KG a

=

1 kG a

H

1

H

L

G

L1 af+kLd1 ad1 +kLd2 ad2

+k a=k a+k

(38)

The experimental KGa can be calculated by the following equation. 32, 33 KG a =

RTQG

πz(r2c -r2i )

NUT =

RTQG

πz(r2c -r2i )

y

ln (y i )

(39)

0

3. Experimental Section The schematic diagram of the experimental setup for the absorption of ozone into 13



Page 14 of 32

organic solution in an RPB is given in Figure 1. The packing of the RPB is made of stainless steel wire mesh. Parameters of the RPB employed in this study is shown in Table 1. Figure 2 illustrates the internal structure of the RPB. Hydroquinone (AR, 98%) and phenol (AR, 99%) were purchased from Tianjin Fuchen Chemical Reagents Factory and Beijing Chemical Works respectively. Ozone was produced from pure oxygen by an ozone generator (3S-A10, Tonglin High-Tech Technology Co. Ltd., Beijing, China), and the ozone concentration was detected by a gaseous ozone concentration detector (3S-J5000, High-Tech Technology Co. Ltd., Beijing, China). The ozone gas was introduced into the RPB from a gas inlet and flowed inward through the cavity and packing zones in succession. The organic solution was introduced into the RPB from a liquid inlet and sprayed onto the inner edge of the packing and flowed outward through the packing and cavity zones successively. The ozone gas and the organic solution contacted countercurrently in the packing and cavity zones, allowing for the absorption of ozone into the solution with pseudo-first-order irreversible reaction. Afterwards, the gas and solution were discharged from the gas outlet and liquid outlet respectively. The outlet gas was monitored by another gaseous ozone concentration detector (UV-100, LIMICEN, Guangzhou, China) before discharged through a gas vent. The outlet ozone concentration was recorded when the concentration reached stability, and the total duration of each experiment was about 30 s to 90 s depending on the gas flow rate. The ozone absorption percentage (𝛽𝑎 ) is defined by equation (40). βa (%) =

ci -cout ci

×100%

(40)

The concentration of hydroquinone solution was determined by a UV-Vis spectrophotometer (DR6000, Hach, America) at an absorbance of 288 nm and a highperformance liquid chromatography (HPLC, Waters, America) was employed to determine the concentration of phenol solution at a wavelength of 270 nm. The degradation percentage of hydroquinone and phenol is calculated by equation (41). The pH and temperature of the solutions were set as 3 and 298 K respectively in all the experiments. 14


Page 15 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


βd (%) =

corganic-0 -corganic-t corganic-0

×100%

(41)

Figure 1. Experimental setup for ozone absorption into organic solution. (1) oxygen cylinder; (2) ozone generator; (3) inlet ozone detector; (4) outlet ozone detector; (5) RPB; (6) pump; (7) untreated liquid tank; (8) magnetic stirrer; (9) treated liquid tank; (10) gaseous ozone inlet; (11) gaseous ozone outlet; (12) liquid inlet; (13) liquid outlet.

15



Page 16 of 32

Figure 2. Illustration of the internal structure of RPB.

Table 1. Parameters of RPB employed in this study.

Item

Units

Value

inner radius of the packing (ri)

m

0.04

outer radius of the packing (ro)

m

0.12

axial length of the packing (zi)

m

0.015

outer radius of the cavity (rc) axial length of the cavity (zo) specific area of the packing (af) voidage of the packing (ε) layer of the packing (n)

m m 2 m ·m-3 % -

0.18 0.03 522 97 20

4. Results and discussion 4.1 Determination of suitable initial hydroquinone (or phenol) concentration The assumption of pseudo-first-order reaction of ozone and organic compounds (first order with respect to ozone and zero order with respect to the organic compound) in the liquid film holds only if the initial concentration of the organic compound is excess for ozone. Therefore, the suitable initial concentration of hydroquinone (or phenol) should be determined. 16


Page 17 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 3 demonstrates that ozone absorption percentages and degradation percentage of hydroquinone or phenol at pH of 3 with and without 0.015 mol·L-1 tertbutanol as a radical scavenger are similar, indicating that the direct reaction of ozone with hydroquinone or phenol predominates and the indirect reaction of the hydroxyl radicals with the organic compounds can be ignored at pH of 3, which was thus chosen as a suitable pH to investigate the direct reaction of ozone with hydroquinone or phenol. Figure 4 presents the ratio of consumed ozone to degraded organic compound (Z, mol·mol-1) as a function of the initial concentration of the organic compound. It can be seen that Z decreased firstly and then tended to be stable with an increase in the initial concentration of hydroquinone and phenol. When the concentrations of hydroquinone and phenol were less than 150 and 200 mg·L-1 respectively, Z decreased sharply, suggesting that the presence of competitive reactions also consumed ozone molecules. When the concentrations of hydroquinone and phenol increased over 150 and 200 mg·L-1, respectively, Z reached stability, which means ozone was almost totally consumed by hydroquinone or phenol.34 Hence, the suitable concentration for both hydroquinone solution and phenol solution was determined as 200 mg·L-1, which was adopted in the following studies. It can be seen from Figure 4 that Z was about 3 for hydroquinone solution and 2.5 for phenol solution when their initial concentration was over 200 mg·L-1. Therefore, degradation percentage of the organic compound is not given here because it can be deduced from the inlet ozone concentration, ozone absorption percentage and Z.

17



Absorption or degradation percentage (%)

100 Ozone absorption percentage without tert-butanol Ozone absorption percentage with tert-butanol Degradation percentage without tert-butanol Degradation percentage with tert-butanol

80

60

40

20

0 Hydroquinone

Phenol

Figure 3. Ozone absorption and organics degradation percentages in hydroquinone and phenol solutions at pH of 3.

Z, mol ozone consum. /mol hydroquinone (or phenol) consum.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 32

9 Hydroquinone Phenol

8 7 6 5 4 3 2 1 0

100

200

300

400

500 -1

Initial concentration of hydroquinone (or phenol) (mg·L )

Figure 4. Variation of Z with the initial concentration of organic compound. (Ro = 800 rpm, L = 60 L·h-1, Gi = 60 L·h-1, ci = 50 mg·L-1)

4.2 Model predictability 18


Page 19 of 32

Ozone will pass through gas and liquid films when absorbed from gas into liquid. And KGa consists of gas (kGa) and liquid (kLa) mass-transfer coefficients. When a fast reaction occurs in liquid, KGa is approximately equal to kGa. Thus the comparison of the experimental KGa with the predicted KGa and kGa for ozone absorption into hydroquinone solution and phenol solution was conducted. Figure 5 presents the predicted KGa and experimental KGa in hydroquinone solution and phenol solution. The results indicate the deviations of the experimental and predicted KGa were within 10% and 15% for hydroquinone solution and phenol solution respectively, suggesting that the model has good predictability for the absorption of ozone into organic solution in RPB with different reaction rates (phenol is 1.3×103 L·mol-1·s-1 and hydroquinone is 1.8×106 L·mol-1·s-1). Figure 5a shows that the deviations between the experimental KGa and predicted kGa were within 15% for hydroquinone solution. These results reveal that the kGa from the model has a certain predictability, although not as precise as the KGa from the model, for the reactive absorption of ozone in RPB with a high reaction rate. The deviations between the experimental KGa and predicted kGa in phenol solution were in the range of approximately 200 - 600%, as shown in Table 2. Thus kGa from the model cannot be used to predict KGa for the reactive absorption of ozone in RPB with a relatively low reaction rate.

4.5

(a) s-1) m-3· pa-1· Predicted KGa or kGa (×105 mol·

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


+10%

4.0 +15%

-10%

3.5

3.0

2.5

-15%

KG a kGa

2.0 2.0

2.5

3.0

3.5

Experimental KGa (×105 mol·pa-1·m-3·s-1)

19


4.0

4.5


1.4 s-1) m-3· pa-1· Predicted KGa (×105 mol·

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 20 of 32

(b)

1.3 +10% +15%

1.2 1.1 1.0

-10%

0.9 -15%

0.8 0.7 0.6 0.6

0.7

0.8

0.9

1.0

1.1 5

1.2 -1

1.3

1.4

-3 -1

Experimental KGa (×10 mol·pa ·m ·s )

Figure 5. Diagonal graph of experimental and predicted KGa (kGa) values in (a) hydroquinone, (b) phenol solution

Table 2. Deviations between experimental KGa and predicted kGa in phenol solution Experimental KGa ×105 mol·pa-1·m-3·s-1

Predicted kGa ×105 mol·pa-1·m-3·s-1

Deviation %

0.6726 0.8419 0.8743 0.9231 0.9693 0.9744 0.9995 1.0006 1.0071 1.0246 1.0554 1.0554 1.1359 1.1359 1.1471 1.1496 1.1575 1.1702 1.1918

2.2100 3.5772 2.8007 3.0119 2.8496 3.2776 2.5824 2.0011 3.6360 3.4300 3.7099 3.7099 3.7151 3.7151 3.6450 3.8422 3.9152 3.6547 4.2945

328.60 424.89 320.34 326.30 293.98 336.36 258.38 199.99 361.05 334.76 351.52 351.52 327.06 327.06 317.76 334.21 338.26 312.31 360.34

20


Page 21 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1.1941 1.1984 1.2366 1.2433 1.2473 1.2599 1.3124 1.3317 1.3516 1.3596 1.3909

4.3176 4.7139 6.0688 3.7099 4.8582 3.6734 3.6943 4.4675 3.7151 8.0046 7.0850

361.59 393.34 490.75 298.38 389.49 291.55 281.48 335.48 274.87 588.76 509.36

4.3 Effect of rotation speed The effect of rotation speed of the RPB on KGa is shown in Figure 6a. It can be seen that KGa increased for both hydroquinone and phenol solutions with the increase of rotation speed from 200 to 1200 rpm. Liquid is split into smaller droplets with larger surface area and the surface renewal rate of liquid increases with an increasing rotation speed, leading to a larger kLa. Since kLa contributes notably to KGa for ozone absorption into those solutions, a larger KGa resulted due to a higher rotation speed. These results indicate that RPB is suitable for the intensification of ozone absorption with fast reactions. Figure 6b shows ozone absorption percentage in hydroquinone solution and phenol solution at various rotation speed. It can be found that ozone absorption reached more than 90% in hydroquinone solution and about 50 - 60% in phenol solution. Compared to phenol, hydroquinone has a faster reaction rate with ozone (1.8 × 106 L·mol-1·s-1 vs. 1.3×103 L·mol-1·s-1), leading to a higher kLa and thereby higher KGa as shown in Figure 6a and better ozone absorption effect.

21



1.6

(a) 1.4 3.2 1.2

2.8

1.0

0.8 2.4

Predicted, in hydroquinone solution Experimental, in hydroquinone solution Predicted, in phenol solution Experimental, in phenol solution

2.0

0.6

s-1) for phenol solution m-3· pa-1· KGa(×105 mol·

s-1) for hydroquinone solution m-3· pa-1· KGa(×105 mol·

3.6

0.4 200

400

600

800

1000

1200

Rotation speed (rpm)

100

(b) 80 Ozone absorption percentage (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 22 of 32

60

40

20

Ozone absorption percentage in hydroquinone solution Ozone absorption percentage in phenol solution 0 200

400

600

800

1000

1200

Rotation speed (rpm)

Figure 6. Effect of rotation speed on (a) KGa and (b) ozone absorption percentage in RPB. (L = 60 L·h-1, Gi = 60 L·h-1, ci = 50 mg·L-1)

4.4 Effect of liquid flow rate

22


Page 23 of 32

Figure 7 demonstrates the effect of liquid flow rate on KGa and ozone absorption in hydroquinone and phenol solutions. It can be seen that KGa and ozone absorption percentage in both hydroquinone and phenol solutions increased with an increase in the liquid flow rate from 15 to 90 L·h-1. The increase of liquid flow rate can cause an increase in the specific surface area of liquid and liquid holdup and a decrease in the mean lifetime of filmy liquid, thereby leading to an increase of kLa and KGa as well as ozone absorption percentage in these two solutions. These results suggest that higher liquid flow rate is beneficial for mass transfer in systems with fast reactions.

5.0

4.0

(a) 4.5

3.5


4.0

3.0

3.5

2.5

3.0

2.0

2.5

1.5

2.0

1.0

1.5

0.5

1.0 10

20

30

40

50

60

70

Liquid flow rate (L·h-1)

23


80

90

0.0 100

KGa(×105 mol·pa-1·m-3·s-1) for phenol solution

KGa(×105 mol·pa-1·m-3·s-1) for hydroquinone solution

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60



100

(b) Ozone absorption percentage (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 32

80

60

40

20

Ozone absoption percentage in hydroquinone solution Ozone absoption percentage in phenol solution

0 10

20

30

40

50

60

70

80

90

100

-1

Liquid flow rate (L·h )

Figure 7. Effect of liquid flow rate on (a) KGa and (b) ozone absorption percentage in RPB. (RO=800 rpm, Gi = 60 L·h-1, ci = 50 mg·L-1)

4.5 Effect of gas flow rate The effect of gas flow rate on KGa and ozone absorption in hydroquinone and phenol solutions is given in Figure 8, which shows that KGa in both hydroquinone and phenol solutions rose with an increase of the gas flow rate from 45 to 180 L·h-1. Because KGa in both hydroquinone and phenol solutions is affected by kGa, an increase in the gas flow rate can cause the rise in gas turbulence and the decline in gas film thickness, thereby leading to the increase of kGa and KGa. It can be seen that the increase in KGa in hydroquinone solution was greater than that in phenol solution because the influence of kGa on KGa in hydroquinone solution is more significant than that in phenol solution. Figure 8b shows that ozone absorption percentage decreased with an increase in gas flow rate as a result of rising gas-liquid ratio.

24


Page 25 of 32

4

(a) 6

3

4

2

2


0 40

60

80

100

120

140

160

180

1

s-1) for phenol solution m-3· pa-1· KGa(×105 mol·

s-1) for hydroquinone solution m-3· pa-1· KGa(×105 mol·

8

0 200

Gas flow rate (L·h-1)

100

(b) Ozone absorption percentage (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


80

60

40

20

Ozone absoption percentage in hydroquinone solution Ozone absoption percentage in phenol solution 0 40

60

80

100

120

140

160

180

200

-1

Gas flow rate (L·h )

Figure 8. Effect of gas flow rate on (a) KGa and (b) ozone absorption percentage in RPB. (RO=800 rpm, L = 60 L·h-1, ci = 50 mg·L-1)

4.6 Effect of inlet ozone concentration

25



Figure 9a shows that KGa in hydroquinone solution and phenol solution went up with a rising inlet ozone concentration. A higher inlet ozone concentration can enhance the mass transfer in gas film and thus kGa and KGa increases with the increase of inlet ozone concentration. Similar to Figure 8a, the increase in KGa in hydroquinone solution was greater than that in phenol solution with rising inlet ozone concentration. A higher inlet ozone concentration leads to a higher kGa, which affects KGa more markedly in hydroquinone solution and gives rise to a greater increase in KGa. Figure 9b indicates that ozone absorption percentage increased with an increasing inlet ozone concentration. These phenomena are ascribed to the combined effect of a higher KGa and driving force for mass transfer of ozone as a result of higher gaseous ozone concentration.

5

2.5

(a) 4


2.0

3 1.5 2

1.0 1

0

0.5 20

30

40

50

60

Inlet ozone concentration (mg·L-1)

26


70



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 26 of 32

Page 27 of 32

100


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


60

40

20

Ozone absoption percentage in hydroquinone solution Ozone absoption percentage in phenol solution 0 20

30

40

50

60

70

-1

Inlet ozone concentration (mg·L )

Figure 9. Effect of inlet ozone concentration on (a) KGa and (b) ozone absorption percentage in RPB. (RO=800 rpm, Gi =60 L·h-1, L = 60 L·h-1)

4.7 Initial concentration of organic compound The effect of the initial concentration of hydroquinone and phenol on KGa is shown in Figure10a. KGa increased as the initial concentration increased, and the rise of KGa in phenol solution was greater than that in hydroquinone solution. An increase in the initial concentration of organic compound can enhance the apparent reaction rate of ozone with the compound, leading to a higher kLa. Hence, KGa is expected to increase with an increasing initial concentration of organic compound. It was also noted that KGa in phenol solution was affected by kLa more significantly than that in hydroquinone solution, resulting in a greater increase of KGa in phenol solution from 1.07×10-5 to 1.38×10-5 mol·pa-1·m-3·s-1 when the initial phenol concentration increased from 200 to 600 mg·L-1, while KGa in hydroquinone solution increased only from 3.40×10-5 to 3.49×10-5 mol·pa-1·m-3·s-1. 27



Figure 10b presents the effect of the initial concentration of organic compound on ozone absorption percentage. Ozone absorption percentage in phenol solution was 60% - 66%, while ozone absorption percentage in hydroquinone solution reached 93% - 94% as a result of a higher KGa.

3.8

1.8

(a)


3.6

1.6

3.4

1.4

3.2

1.2

3.0

1.0 200

300

400

500

Initial concentration of organic compound (mg·L-1)

28


600



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 28 of 32

Page 29 of 32

100


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


80

70

60

50

Ozone absoption percentage in hydroquinone solution Ozone absoption percentage in phenol solution

40 200

300

400

500

600 -1

Initial concentration of organic compound (mg·L )

Figure 10. Effect of initial concentration of organic compound on (a) KGa and (b) ozone absorption percentage in RPB. (RO=800 rpm, Gi =60 L·h-1, L = 60 L·h-1, ci = 50 mg·L-1)

5. Conclusion In this work, by obtaining the analytical expression of the concentration distribution of ozone with respect to time and penetration depth in liquid film as well as the analytical expression of gas-liquid mass transfer coefficient, a mathematic model of ozone absorption into organic solution accompanied by an irreversible pseudo-firstorder reaction in an RPB was developed for the quantitative description of the mass transfer process of ozone in the RPB and the prediction of KGa. It is found that the KGa values predicted by the model were in good agreement with the experimental values. And the deviations of the experimental and predicted KGa were within 10% and 15% for hydroquinone solution and phenol solution respectively, suggesting that the model has good predictability for the absorption of ozone into organic solution in RPB with different reaction rates. The comparison of KGa of ozone absorption into hydroquinone solution and phenol solution reveal that KGa is affected more significantly by kGa with an increasing reaction rate of ozone and organic 29



compound. Experimental results indicate that a higher rotation speed of the RPB, liquid flow rate, gas flow rate and inlet ozone concentration is favorable for the mass transfer of ozone in the RPB. It was observed that ozone absorption percentage in phenol solution was generally 40% - 60%, while ozone absorption percentage in hydroquinone solution reached approximately 80% - 95% as a result of a higher KGa. This work provides fundamentals for the application of ozone for the treatment of organic wastewater in RPBs.

Acknowledgment This work was supported by the National Natural Science Foundation of China (No. 21676008) and Solvay (China) Co., Ltd.

References (1) Xi, J.; Zhang, F.; Lu, Y.; Hu, H. A novel model simulating reclaimed water disinfection by ozonation. Sep. Purif. Technol. 2017, 179, 45-52. (2) Wolf, C.; von Gunten, U.; Kohn, T. Kinetics of Inactivation of Waterborne Enteric Viruses by Ozone. Environ. Sci. Technol. 2018, 52, 2170-2177. (3) von Gunten, U. Oxidation Processes in Water Treatment: Are We on Track? Environ. Sci. Technol. 2018, 52, 5062-5075. (4) Mvula, E.; von Sonntag, C. Ozonolysis of phenols in aqueous solution. Org. Biomol. Chem. 2003, 1, 1749-1756. (5) Scott, J.; Ollis, D. F. Integration of chemical and biological oxidation processes for water treatment: Review and recommendations. Environ. Prog. 1995, 14, 88-103. (6)Lee, C.; Howe, K.; Thomson, B. Ozone and biofiltration as an alternative to reverse osmosis for removing PPCPs and micropollutants from treated wastewater. Water Res. 2012, 46, 1005-1014. (7) Poznyak, T.; Bautista, G.; Chaí rez, I.; Córdova, R.; Rí os, L. Decomposition of toxic pollutants in landfill leachate by ozone after coagulation treatment. J. Hazard. Mater. 2008, 152, 1108-1114. (8) Kalyanaraman, C.; Kameswari, K. ; Rao, J. Studies on enhancing the biodegradation of tannins by ozonation and Fenton's oxidation process. J. Ind. Eng. Chem. 2015, 25, 329-337. (9) Vaiopoulou, E.; Misiti, T.; Pavlostathis, S. Removal and toxicity reduction of naphthenic acids by ozonation and combined ozonation-aerobic biodegradation. Bioresour. Technol. 2015, 179, 339347. (10) Van Aken, P.; Van den Broeck, R.; Degrève, J.; Dewil, R. The effect of ozonation on the toxicity and biodegradability of 2,4-dichlorophenol-containing wastewater. Chem. Eng. J. 2015, 280, 728-736. (11) Wu, C.; Zhou, Y.; Sun, X.; Fu, L. The recent development of advanced wastewater treatment by ozone and biological aerated filter. Environ. Sci. Pollut. Res. 2018, 25, 8315-8329. (12) Lovato, M.; Buffelli, J.; Abrile, M.; Martí n, C. Kinetics and efficiency of ozone for treatment 30


Page 30 of 32

Page 31 of 32 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


of landfill leachate including the effect of previous microbiological treatment. Environ. Sci. Pollut. Res. 2019, 26, 4474-4487. (13) Ramshaw, C., Mass Transfer Process. U. S. Patent 4,283,255 1981. (14) Sang, L.; Luo, Y.; Chu, G.; Liu, Y.; Liu, X.; Chen, J. Modeling and experimental studies of mass transfer in the cavity zone of a rotating packed bed. Chem. Eng. Sci. 2017, 170, 355-364. (15) Cheng, H.; Tan, C. Reduction of CO2 concentration in a zinc/air battery by absorption in a rotating packed bed. J. Power Sources 2006, 162, 1431-1436. (16) Lin, C.; Chen, Y. Performance of a cross-flow rotating packed bed in removing carbon dioxide from gaseous streams by chemical absorption. Int. J. Greenhouse Gas Control 2011, 5, 668-675. (17) Liu, Y.; Zhang, F.; Gu, D.; Qi, G.; Jiao, W.; Chen, X. Gas-phase mass transfer characteristics in a counter airflow shear rotating packed bed. Can. J. Chem. Eng. 2016, 94, 771-778. (18) Sun, B.; Wang, X.; Chen, J.; Chu, G.; Chen, J.; Shao, L. Simultaneous Absorption of CO2 and NH3 into Water in a Rotating Packed Bed. Ind. Eng. Chem. Res. 2009, 48, 11175-11180. (19) Guo, K.; Wen, J.; Zhao, Y.; Wang, Y.; Zhang, Z.; Li, Z.; Qian, Z. Optimal packing of a rotating packed bed for H(2)S removal. Environ. Sci. Technol. 2014, 48, 6844-6849. (20) Chu, G.; Luo, Y.; Shan, C.; Zou, H.; Xiang, Y.; Shao, L.; Chen, J. Absorption of SO 2 with Ammonia-Based Solution in a Cocurrent Rotating Packed Bed. Ind. Eng. Chem. Res. 2014, 53, 15731-15737. (21) Zeng, Z.; Zou, H.; Li, X.; Arowo, M.; Sun, B.; Chen, J.; Chu, G.; Shao, L. Degradation of phenol by ozone in the presence of Fenton reagent in a rotating packed bed. Chem. Eng. J. 2013, 229, 404-411. (22)Li, M.; Zeng, Z.; Li, Y.; Arowo, M.; Chen, J.; Meng, H.; Shao, L. Treatment of amoxicillin by O3/Fenton process in a rotating packed bed. J. Environ. Manage. 2015, 150, 404-411. (23) Wei, Q.; Qiao, S.; Sun, B.; Zou, h.; Chen, J. F.; Shao, L. Study on the Treatment of Simulated Coking Wastewater by O3 and O3/Fenton Processes in a Rotating Packed Bed. RSC Adv. 2015, 5, 93386-93393. (24) Ge, D.; Zeng, Z.; Arowo, M.; Zou, H.; Chen, J.; Shao, L. Degradation of methyl orange by ozone in the presence of ferrous and persulfate ions in a rotating packed bed. Chemosphere 2016, 146, 413-418. (25) Wang, D.; Wang, W.; Liu, T.; Shan, M.; Li, G.; Arowo, M.; Shao, L. Ozonation of polyoxymethylene effluent in a rotating packed bed. Environ. Technol. 2017, 40, 807-812. (26) Lin, C.; Liu, W. Ozone oxidation in a rotating packed bed. J. Chem. Technol. Biotechnol. 2003, 78, 138-141. (27) Beltrán, F.; Alvarez, P. Rate constant determination of ozone‐organic fast reactions in water using an agitated cell. J. Environ. Sci. Health, Part A: Toxic/Hazard. Subst. Environ. Eng. 1996, 31, 1159-1178. (28) Burns, J.; Jamil, J.; Ramshaw, C. Process intensification: operating characteristics of rotating packed beds — determination of liquid hold-up for a high-voidage structured packing. Chem. Eng. Sci. 2000, 55, 2401-2415. (29) Qian, Z.; Xu, L.; Cao, H.; Guo, K. Modeling Study on Absorption of CO2 by Aqueous Solutions of N-Methyldiethanolamine in Rotating Packed Bed. Ind. Eng. Chem. Res. 2009, 48, 9261-9267. (30) Onda, K.; Takeuchi, H.; Okumoto, Y. Mass Transfer Between Gas and Liquid Phases in Packed Columns. J. Chem. Eng. Jpn. 1968, 1, 56-62. 31



(31) Guo, F.; Zheng, C.; Guo, K.; Feng, Y.; Gardner, N. Hydrodynamics and mass transfer in crossflow rotating packed bed. Chem. Eng. Sci. 1997, 52, 3853-3859. (32) Kelleher, T.; R. Fair, J. Distillation Studies in a High-Gravity Contactor. Ind. Eng. Chem. Res. 1996, 35, 4646-4655. (33) Sandilya, P.; Rao, D.; Sharma, A.; Biswas, G. Gas-Phase Mass Transfer in a Centrifugal Contactor. Ind. Eng. Chem. Res. 2001, 40, 384-392. (34) Sotelo, J.; J. Beltran, F.; Gonzalez, M. Ozonation of aqueous solutions of resorcinol and phloroglucinol. 1. Stoichiometry and absorption kinetic regime. Ind. Eng. Chem. Res. 1990, 29, 2358-2367.

32


Page 32 of 32

Modeling and experimental studies on ozone absorption into phenolic

Recommend Documents