Vol.:(0123456789)
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Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
h ps://doi.o g/10.1007/s13399-022-02493-2
ORIGINAL ARTICLE
Ca aly ic py olysis o da e palm seeds onHZSM‑5 anddolomi e
inapy op obe eac o inline wi hGC/MS
Mi iamA abiou u ia1· Gma Bensidhom2· Maide Bolaños1· AïdaBenHassenT abelsi2· Ma inOlaza 1
Recei ed: 6 Decembe 2021 / Re ised: 9 Feb ua y 2022 / Accep ed: 19 Feb ua y 2022 / Published online: 11 Ma ch 2022
© The Au ho (s) 2022
Abs ac
Ca aly ic py olysis o da e palm seeds (DPS) has been ca ied ou in a py op obe connec ed online wi h a GC/MS. The e ec
o a HZSM-5 zeoli e on he p oduc dis ibu ion has been s udied a 450 and 500 °C by using di e en ca alys /biomass mass
a ios (1, 2, 5) and ha o a dolomi e ca alys a 450 °C using a ca alys /biomass mass a io o one. P oduc dis ibu ions
ha e been moni o ed and hei ends explained based on he p ope ies o he ca alys s used. The HZSM-5 p omo es he
o ma ion o incondensable gases and a oma ic hyd oca bons due o i s high acidi y and shape selec i i y. The concen a-
ions o incondensable gases and hyd oca bons inc ease ma kedly wi h he ca alys /biomass mass a io, wi h hei peak a ea
pe cen ages anging om 23.6 o 54.1% and om 7.1 o 24.5%, espec i ely. A he same ime, a signi ica i e educ ion
in he amoun o acids, ke ones, phenols, u ans, and anhyd osuga s has been de e mined. The dolomi e ca alys enhances
ke oniza ion eac ions, which leads o a signi ican inc ease in he con en o ke ones, accoun ing o a alue o a ound 27%.
Keywo ds DPS biomass· Py-GC/MS· Ca aly ic py olysis· Zeoli e HZSM-5· Dolomi e
1 In oduc ion
Biomass is a enewable ene gy sou ce, which may be used
o eplace ossil uels, and so mee he inc easing ene gy
demand. Py olysis o biomass is an in e es ing op ion o
manage o es y and ag icul u al was es and, a he same
ime, ob ain p oduc s wi h a high po en ial applica ion o
ene gy p oduc ion o sou ce o alue-added chemicals con-
ained in he gaseous and/o liquid bio-oil ac ion [1, 2].
The bio-oil o py oly ic oil gene a ed om he as
py olysis o biomass and was es may ha e se e al po en ial
applica ions, such as hose ela ed o he p oduc ion o high
alue-added chemicals and subs i u es o pe oleum-based
sou ces o a wide ange o uels [3]. C ude bio-oil de i ed
om he con en ional as py olysis is a low-g ade liquid
uel due o he high oxygen con en , poo s abili y, high
acidi y, and low calo i ic alue. Fu he mo e, eco e y o
aluable chemicals is a e y di icul ask due o hei low
con en s in he bio-oil. Acco dingly, he liquid p oduc mus
be upg aded p io o use in ele an applica ions by means o
sui able p ocesses, such as ca aly ic c acking, which in u n
mus in ol e easonable cos s.
Ca aly ic as py olysis is conside ed a p omising
app oach o con e oxygena e compounds in o a a ie y
o hyd oca bons and he e o e imp o e he bio-oil quali y.
The use o a ca alys gene ally enhances he a ge ed eac-
ions; educes he eac ion ime and empe a u e; imp o es
he liquid oil quali y by emo ing oxygen ia ce ain eac-
ions, such as dehyd a ion ( emo ing oxygen as H2O), deca -
boxyla ion ( emo ing oxygen as CO2), and deca bonyla ion
( emo ing oxygen as CO) [4, 5]; and inc eases he o e all
p ocess e iciency [6]. The su ace a ea, acidi y, and po e
size and olume a e he key ea u es o any ca alys a ec ing
he py olysis p ocess [7].
The e a e many s udies in he li e a u e dealing wi h
he ca aly ic py olysis o biomass and was es as a way o
ob ain upg aded py oly ic p oduc s [8, 9]. Thus, acid ca a-
lys s such as HZSM-5 zeoli e-based ones ha e been epo ed
o pe o m well in deoxygena ion o ob ain hyd oca bons.
* Mi iam A abiou u ia
mi iam.a abiou [email p o ec ed]
1 Depa men o Chemical Enginee ing, Uni e si y
o heBasque Coun y UPV/EHU, P.O. Box644,
E48080Bilbao, Spain
2 Cen e de Reche ches e des Technologies de l’Ene gie
Technopole De Bo j-C´ed ia, BP: 95, Hamam Li ,
BenA ous, Tunisia
2800 Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
This beha io has been a ibu ed o hei acidi y and shape
selec i i y [5, 10], wi h he la e being a consequence o i s
small/medium-po e size coupled wi h i s wo-dimensional
channel-like po e sys em [11]. In he py olysis o bio-
mass, deoxygena ion o holocellulose and lignin agmen s
occu s ia dehyd a ion and deca bonyla ion/deca boxyla-
ion eac ions [12, 13]. Subsequen ly, p o oly ic c acking o
β-scission, alkyla ion, isome iza ion, cycliza ion, oligome i-
za ion, and a oma iza ion eac ions ake place. Among he
zeoli es, he ZSM-5 has been widely used as a ca alys o
biomass py olysis, as i d ama ically changes he composi-
ion o he ola iles gene a ed. One o he main pu poses o
using zeoli ic ca alys s lies in i s capaci y o deoxygena -
ing phenolic and oxygena ed compounds [14]. O he ca a-
lys s, such as alkali sal s [15] and me al oxides [16], ha e
been used, bu a much lowe deoxygena ing ac i i y has
been epo ed. Low-cos ca alys s, ei he na u al (oli ine,
alumina) o syn he ic (spen FCC ca alys ), ha e also been
used in line wi h he py olysis eac o , and hey led o a
signi ican dec ease in acid and phenolic compounds in he
ola ile s eam, making i sui able o u he ca aly ic al-
o iza ion o he p oduc ion o H2, uels, and chemicals [17].
O he s udies in which na u al ma e ials ha e been used as
ca alys s a e hose by Aljbou [18] and Alje ada e al. [19].
Dolomi e is a na u al, inexpensi e, and non-me allic
ca alys , which has been widely used o a con e sion in
biomass gasi ica ion [20, 21]. Howe e , his na u al ca alys
has also been used success ully in he ca aly ic py olysis o
biomass o imp o e he bio-oil quali y by c acking hea y
o ganic molecules o ligh e ones o emo ing oxygen om
he oxygena es [22]. Fu he mo e, his ca alys has also been
used o upg ade he liquid bio-oil p io o eeding in o he
e o ming eac o . Thus, Valle e al. [23] concluded ha
dolomi e was e ec i e o he deoxygena ion o he bio-oil,
as i educes he O con en , and so he O/C a io, in he
upg aded bio-oil. Ly e al. [22] used dolomi e as a ca alys
in a luidized bed and p o ed ha i leads o he o ma ion
o a oma ic compounds (C5-C11), such as he de i a i es o
u u al, ke ones, and phenolic compounds. Ano he posi-
i e bene i o dolomi e lies in i s capaci y o CO2 cap u e,
which allows ob aining a gaseous p oduc wi h a low yield
o CO2 [24]. Dolomi e emo es oxygen om he py olysis
s eam mos ly h ough dehyd a ion, ins ead o deca boxyla-
ion o deca bonyla ion [22].
In his wo k, da e palm seeds ha e been used as he aw
ma e ial. The da e palm ee is a ypical cul i a ed ee in he
a id and semi-a id egions o he wo ld. The e a e mo e han
100–120 million da e palm ees wo ldwide, wi h mos o
hem (70–90%) being loca ed in he Middle Eas and No h
A ica (MENA) coun ies [25]. I is especially abundan in
se e al egions in he Sou h o Tunisia [26].
Da e seeds a e low-cos ag icul u al by-p oduc s, which
a e adi ionally used o animal eed. Thei de i ed powde
is used as a co ee subs i u e [27, 28]. They a e also used as a
sou ce o oil in cosme ics due o hei an ioxidan p ope ies,
aw ma e ial o ac i a ed ca bon, adso ben o dye-con ain-
ing wa e s, and CO2 cap u e ma e ial [29–31]. The annual
wo ld p oduc ion o da es is o a ound 9 million ons [29].
Depending on he a ie y, da e seeds accoun o 6.10–11.4%
o he whole ui weigh [32].
This s udy analyzes he pe o mance o a HZSM-5 zeoli e
ca alys by a ying empe a u es (450 and 500 °C) a he
ca alys /biomass mass a io o C/B=1 and ca alys /biomass
mass a io (C/B=1, 2, and 5) a he empe a u e o 450 °C. A
de ailed quan i ica ion and iden i ica ion o he compounds
o med ha e been ca ied ou , wi h emphasis placing on he
di e en ends obse ed in he p oduc dis ibu ion and
ela ing hese ends o he p ope ies o he ca alys s used.
Fu he mo e, a low-cos na u al ca alys wi h e y di e en
p ope ies, as is dolomi e, has been used o analyze i s e ec
on he p oduc dis ibu ion and compa e i s pe o mance
wi h ha o he HZSM-5. The aim o his s udy is o show
ha upg ading o he condensable ac ion (bio-oil) allows
imp o ing he quali y o he liquid and he e o e inc eases
i s po en ial o use as uel. In ac , he p esence o alipha ic
and a oma ic hyd oca bons in he liquid is c ucial o a high-
quali y uel. Fu he mo e, i is well-known ha ca aly ic
py olysis enhances he p oduc ion o hyd oca bons. To ou
knowledge, he e a e no s udies epo ed in he li e a u e
abou he ca aly ic py olysis o da e palm seeds. The e o e,
his s udy con ibu es o p omo ing py olysis p ocesses as
an op ion o alo ize hese was es.
2 Expe imen al
2.1 P epa a ion andcha ac e iza ion o da e palm
seed samples
Da e palm seeds (DPS) we e supplied by he Na ional Ins i-
u e o A id Zone (IRA-Kebili, Tunisia). The so o da e
used was Degle Noo seeds (Phoenix Dac yli e a L.). The
DPS we e ha es ed om he da e ui by hand and hen
cleaned wi h dis illed wa e o elimina e all dus . They we e
hen sund ied o 3 days. Mo eo e , he sund ied biomass
was c ushed in o pa icle sizes anging be ween 0.125 and
0.25 mm and s o ed in ai igh plas ic bags o p e en mois-
u e abso p ion. This pa icle size ange is he sui able one
o ca y ou as py olysis in a Py-GCMS, whe e e y small
quan i ies o sample a e used, o a ound 1 mg.
A he mog a ime ic analyze (TGA Q5000 IR) was used
in his s udy o de e mine he p oxima e analysis o he DPS
samples. The p ocedu e was desc ibed elsewhe e [33].
DPS ul ima e analysis was pe o med using an elemen al
analyze (LECO CHNS TRuSpec). The O con en was de e -
mined by di e ence, acco ding o he ollowing exp ession:
2801Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
The highe hea ing alue (HHV) o he aw ma e ial DPS
was measu ed by means o a CAL-2 K Oxygen Bomb Calo-
ime e acco ding o he ASTM D5865-13 s anda d me hod.
The lignocellulosic componen s (cellulose, hemicellu-
lose, and lignin) o he DPS sample we e de e mined acco d-
ing o he me hod desc ibed elsewhe e [34].
2.2 Py‑GC/MS equipmen
The py olysis o DPS has been ca ied ou in a Py op obe
5150 o CDS. One millig am o he sample was inse ed in
he py olysis ube, wi h qua z wool being placed abo e and
below he sample. Py olysis uns we e ca ied ou a 450
and 500 °C o 40 s. This ime is su icien ly long o ensu e
all he ola ile ma e is py olized. The expe imen s we e
conduc ed in iplica e and he mean alues and he s anda d
de ia ions we e de e mined. In he ca aly ic py olysis, he
biomass sample was mixed wi h he ca alys a he ca alys /
biomass (C/B) mass a ios o 1, 2, and 5 o he HZSM-5
zeoli e and 1 o he dolomi e ca alys . The hea ing a e was
20 °C/ms. The ola iles gene a ed we e ans e ed h ough a
ho line in o a GC/MS (QP2010 Shimadzu), whe e hey we e
analyzed. The ch oma og aphic sepa a ion was pe o med
using a BPX-5 capilla y column (30 m × 0.22 mm ID, 0.25
μm ilm hickness). The o en empe a u e was p og ammed
om 45 °C (main ained o 3 min) o 295 °C (5 min) wi h a
hea ing a e o 4 °C/min. The MS de ec o was a quad upole
ype. The iden i ica ion o he compounds was ca ied ou
using he NIST lib a y.
2.3 Ca alys s
The ca alys s used a e a HZSM-5 zeoli e and a dolomi e. The
HZSM-5 zeoli e has been chosen because o i s good deoxy-
gena ion capaci y gi en by i s speci ic p ope ies (acidi y
and shape selec i i y). The dolomi e ca alys has been cho-
sen because o , on he one hand, low cos and, on he o he
hand, di e en p ope ies o hose o he zeoli e, e.g., poo
po ous s uc u e and basic na u e.
The ZSM-5 zeoli e has been supplied by Zeolys In e na-
ional (USA) and he dolomi e by Mine als Sibelco (Spain).
The ZSM-5 zeoli e was supplied in ammoniac o m and
calcined a 575 °C o 2 h in o de o ob ain he acid o m
and so a sui able su ace acidi y. The dolomi e has been cal-
cined a 900 °C o 4 h in o de o a ain ull deca boxyla-
ion o calcium and magnesium ca bona es and so ob ain
he ac i e phases o CaO and MgO. XRD analysis has been
ca ied ou o de e mine he c ys alline phases in he dolo-
mi e. The c ys alline s uc u e o he dolomi e was analyzed
using X- ay powde di ac ion (XRD) pa e ns. A B uke
O
(w .%)=100–
[
C(w .%)+H(w .%)+N(w .%
)
D8 Ad ance di ac ome e wi h Cu Kα1 adia ion was used
o conduc he analysis. XRF analysis has been ca ied ou
o measu e he chemical composi ion o he ca alys . This
analysis was ca ied ou using a sequen ial wa eleng h dis-
pe sion X- ay luo escence (WDXRF) spec ome e (Axios
2005, PANaly ical) unde a acuum a mosphe e.
The ex u al p ope ies o bo h ca alys s ha e been de e -
mined om he N2 adso p ion-deso p ion cu es ob ained
in a Mic ome i ics ASAP-2100 equipmen . The o al acidi y
o he HZSM-5 zeoli e has been de e mined in a calo im-
e e (Se a am TG-DSC 111) coupled o a mass spec ome e
(The mos a o Balze s Ins umen s).
3 Resul s
3.1 Biomass cha ac e iza ion
Table1 shows he p oxima e and ul ima e analyses o he
s udied DPS sample, as well as he pe cen ages o hei main
cons i uen s (cellulose, hemicellulose, and lignin).
Da e seeds a e cha ac e ized by hei high con en o ola-
ile ma e and low one o ash componen s. High ola ili y
makes hese biomasses a ac i e o he py olysis p ocess
in o de o ob ain bio-oil and syngas [35].
3.2 Ca alys cha ac e iza ion
Table2 se s ou he physicochemical p ope ies o he
HZSM-5 zeoli e and dolomi e ca alys s. As obse ed, he
zeoli e has much highe su ace a ea and po e olume han
he dolomi e, whe eas he a e age po e size o he dolo-
mi e is much highe han ha o he zeoli e. The la e
is e idence o he mic opo ous s uc u e o he zeoli e.
Conce ning acidi y, he zeoli e is an acid ca alys , whe eas
Table 1 Ul ima e and p oxima e analyses and lignocellulosic compo-
nen s o he s udied DPS
*Calcula ed by di e ence
P oxima e analysis
Mois u e con en (w .%) 1.73
Vola ile ma e con en (w .%) 78.61
Ash con en (w .%) 4.97
Fixed ca bon* (w .%) 14.69
Ul ima e analysis
Ca bon 48.05
Hyd ogen 7.67
Ni ogen 0.70
Oxygen* 43.57
H/C a omic a io 2.23
O/C a omic a io 0.13
HHV (MJ/kg) 20.46
2802 Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
he dolomi e is a basic one. The HZSM-5 has a silica/
alumina a io o 30, which con e s high o al acidi y upon
his ca alys .
The main mine al cons i uen s o he calcined dolomi e
used ha e been de e mined by X- ay luo escence (XRF)
analysis. The chemical composi ion is as ollows: MgO
(w . %) 43.61, SiO2 (w . %) 0.12, Fe2O3 (w . %) 0.02, CaO
(w . %) 56.07, Al2O3 (w . %) 0.15, Na2O (w . %) 0.01, and
TiO2 (w . %) 0.02.
Fig.1 shows he XRD diag am o he calcined dolomi e.
As obse ed, all he peaks co espond o MgO and CaO
phases.
Bo h analyses show ha he main componen s o he
dolomi e ca alys a e CaO and MgO, which a e oxides
con aining basic si es. Besides, i s speci ic su ace a ea
(BET a ea) is e y low and he e o e has a small numbe
o s ong acid si es a ailable. In addi ion, i has a sligh ly
de eloped su ace s uc u e leading o low ac i i y. Ne -
e heless, he HZSM-5 zeoli e has a high speci ic su -
ace a ea and s ong acidi y, leading o a g ea numbe o
su ace acid si es on i s su ace. Acco dingly, he be e
p ope ies o he HZSM-5 zeoli e a e esponsible o i s
highe c acking capaci y, as well as highe deoxygena ion
capaci y.
3.3 Py‑GC/MS esul s
In his sec ion, he esul s ob ained in he ca aly ic py olysis
on he HZSM-5 zeoli e and dolomi e ca alys s a e shown and
hey a e compa ed wi h hose ob ained in a p e ious s udy
ca ied ou wi hou any ca alys [33].
3.3.1 The mal py olysis
In o de o de e mine he e ec o he ca alys s on he ola-
ile p oduc dis ibu ion, he esul s ob ained wi hou ca alys
a e i s ly shown in his subsec ion.
The ola iles gene a ed in he py olysis o biomass co e
a wide ange o compounds o di e en na u e, which may
be classi ied as acids, ke ones, aldehydes, phenols, alcohols,
u ans, e he s, and anhyd osuga s, as well as hyd oca bons,
N compounds, and S compounds in a much lowe amoun .
Those p e e ed o bio uel a e a oma ic hyd oca bons, ali-
pha ic hyd oca bons, and alcohols, whe eas phenols and
u ans a e ega ded as high added- alue chemicals. Acids
a e esponsible o he co osi eness o he bio-oil, and hey
a e he e o e undesi ed compounds. The same s ands o
ke ones and aldehydes, which a e ela ed o he ins abili y
o he bio-oil du ing anspo and s o age. E he s, es e s,
and oxygena es in gene al a e also undesi ed compounds,
as hey educe he hea ing alue o he bio-oil. Polya oma ic
hyd oca bons and ni ogen and sul u compounds a e de i-
men al o he en i onmen [12].
Figu e2 shows he o al ion ch oma og am co esponding
o he as py olysis o DPS pe o med a 450 °C
Table3 shows he e en ion imes, compound names, and
peak a ea pe cen ages o he main compounds ob ained in
he he mal py olysis a 450 °C.
As obse ed, ke ones (ace one and 1-hyd oxy-2-p o-
panone), acids (ace ic, undecanoic, dodecanoic, and
oc adecanoic), and anhyd osuga s (le oglucosan) a e
he p e ailing compound amilies. In addi ion, he con-
en o 5-(hyd oxyme hyl)-2- u anca boxaldehyde is also
conside able.
Table4 shows he peak a ea pe cen ages o he di e en
compound amilies ob ained by he ch oma og aphic analy-
sis o he ou le s eam o he py olysis o DPS samples a
450 and 500 °C.
As obse ed, anhyd osuga s, acids, ke ones, and u ans
a e he mo e abundan compound amilies in he conden-
sable ac ion ob ained. The con en o acids and u ans
inc eases mode a ely wi h empe a u e, whe eas ha o
anhyd osuga s dec eases. The suga con en dec eases ( om
23.1% a 450 °C o 19.2% a 500 °C). Le oglucosan is he
mos abundan compound in he suga amily.
In he acid p oduc - ac ion, ace ic acid, long-chain
acids ( a y acids), and alkyl es e acids a e he p e ail-
ing ones. The main indi idual compounds iden i ied a e
Table 2 Physicochemical p ope ies o he HZSM-5 zeoli e and dolo-
mi e ca alys s
Ca alys BET su ace
a ea (m2/g) Mic opo e
olume
(cm3/g)
dp (Å) Acidi y
(mmol
NH3/g ca .)
HZSM-5 zeoli e 377 0.098 5.2–5.5 0.765
Dolomi e 23 0.0026 173 -----
Fig. 1 The XRD diag am o he calcined dolomi e
2803Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
ace ic acid, decanoic acid, undecanoic acid, dodecanoic
acid, and oc adecanoic acid, wi h he concen a ion o
each o hem being o a ound 2% a 450 °C. Among he
ke ones, ace one p e ails, wi h i s concen a ion being
in he 2.2–2.4% ange. The emaining compounds in his
ke ones amily (o he s) a e mainly linea and cyclic C3-C8
ke ones.
Among he u an amily, 5-hyd oxyme hyl-2- u anca -
boxaldehyde was he main compound iden i ied wi h high
concen a ion, ollowed by u u al and u an de i a i es.
I s o al concen a ion inc eased mode a ely om 9.6% a
450 °C o a ound 14% a 500 °C.
3.3.2 Ca aly ic py olysis on heHZSM‑5 zeoli e
As obse ed in he p e ious sec ion, he oxygena ed com-
pounds a e he p edominan ones in he ola ile s eam
ob ained. This high oxygena ed compound con en con e s
undesi able p ope ies, such as high acidi y, ins abili y, and
low hea ing alue, upon he bio-oil o liquid uel applica-
ions, as well as g ea di icul y o aluable chemical ex ac-
ion [36]. The e o e, upg ading o c ude bio-oil is necessa y
o imp o e uel p ope ies o inc ease he concen a ion o
aluable chemicals. The addi ion o ca alys s in he py olysis
p ocess is a good op ion o o e come his p oblem. Thus,
Fig. 2 Ch oma og am ob ained
in he py olysis o he DPS
sample, T=450 °C
1
2
3
4
56
78910
11
12
13 14 15 16 17
y isne nI
Re en ion ime (min)
y isne nI
Table 3 Re en ion imes,
compound names, and peak
a ea pe cen ages o he main
compounds ob ained in he
he mal py olysis a 450 °C
Peak numbe Re en ion ime
(min) Compound Peak a ea (%)
1 3.36 Ace one 2.51
2 4.31 Ace ic acid 2.13
3 5.21 1-Hyd oxy-2-p opanone 3.27
4 8.64 Ace ic anhyd ide 0.84
5 10.30 Fu u al 1.51
6 11.05 2-Fu anme hanol 1.30
7 14.14 Cyclohexanone 1.35
8 18.30 3-Me hyl-1,2-cyclopen anedione 0.98
9 21.49 Cyclop opyl ca binol 0.86
10 25.41 1,4:3,2-Dianhyd o-d-glucopy anose 2.07
11 26.63 5-(Hyd oxyme hyl)-2- u anca boxaldehyde 4.18
12 27.22 3,4-Anhyd o-d-galac osan 1.28
13 35.87 Le oglucosan 20.89
14 37.20 Undecanoic acid 2.54
15 42.77 Dodecanoic acid 2.45
16 47.91 Oc adecanoic acid 2.13
17 54.28 9-Oc adecenal 0.70
2804 Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
ca alys s wi h sui able p ope ies a o deoxygena ion eac-
ions, and hey he e o e allow (i) ob aining bio-oils wi h
low oxygen con en o liquid uel applica ions [37]; (ii)
dec easing he con en o he oxygena ed compounds, and
so educing he acid con en in he bio-oil; (iii) emo ing
he uns able componen s, such as aldehydes and ke ones;
and (i ) inc easing he con en o phenols and hyd oca -
bons, especially hose o monocyclic a oma ic hyd oca bons
(p omising p oduc s o bo h liquid uels and chemical aw
ma e ials). The las one no only imp o es he ene gy den-
si y o he bio-oil, bu also makes i easie o blend i wi h
c ude oil [38].
Thus, Huynh e al. [39] used HZSM5, Zn/HZSM-5, and
Fe/HZSM-5 ca alys s o upg ading he py olysis oil. They
obse ed ha he quali y o he oil was imp o ed, as uels
wi h highe hea ing alue and lowe acidi y and iscosi y
we e ob ained. They de e mined ha he o al combus ion
cha ac e is ic index o py olysis oils inc eased and ha hey
we e mo e lammable han uel oil. These esul s p o e
ha he upg aded oil migh be used as uel oil in indus ial
applica ions.
Conce ning high-quali y uels, a high con en o alipha ic
hyd oca bons is essen ial, as well as he p esence o a oma ic
hyd oca bons o imp o e he oc ane numbe o he uel [40].
Besides, alipha ic and a oma ic hyd oca bons inc ease he
highe hea ing alue o he bio-oil [41].
P oduc dis ibu ion a 450 °C Figu e3 shows he o al ion
ch oma og am co esponding o he ca aly ic py olysis o
DPS on he HZSM-5 zeoli e (C/B=1, 2, 5) pe o med a
450 °C.
Table5 shows he e en ion imes, compound names, and
peak a ea pe cen ages o main compounds ob ained in he
ca aly ic py olysis on he HZSM-5 zeoli e a 450 °C.
When a C/B=1 is used, he o ma ion o a oma ic com-
pounds is ema kable, i.e., oluene, p-xylene, 1,2,3- ime-
hyl-benzene, and 2,3-dime hyl-naph halene. The mos
abundan compounds co espond o ke ones, acids, and
anhyd osuga s. Fo C/B=2, he inc ease in he ela i e con-
en o a oma ic compounds is wo h men ioning, which is
no he case when a C/B a io o 5 is used. Fu he mo e, he
ela i e con en o ace aldehyde inc eases and hose o acids
and anhyd osuga s dec ease when he C/B a io is aised.
Table6 shows he peak a ea pe cen ages o he di e en
compound amilies ob ained by he ch oma og aphic analy-
sis o he ou le s eam in he ca aly ic py olysis o DPS
samples a 450 °C on he HZSM-5 zeoli e.
As obse ed in Table6, he mos abundan compound
amily is he one o incondensable gases. I s con en
inc eases signi ican ly ( om 23.6 o 54.1%) as ca alys /
biomass (C/B) a io is inc eased om 1 o 5. Only ce ain
compounds ha e been iden i ied in his lump, wi h p opene
being he mos signi ican one, especially when he highes
Table 4 Mean peak a ea pe cen ages (95% con idence in e al) o he
di e en compound amilies ob ained in he he mal py olysis o DPS
a 450 and 500 °C
The bold en ies signi icance is o emake he di e en amilies ca -
ego ies
450 °C 500 °C
Incondensable gases 16.4±0.3 12.2±0.4
Acids 16.9±2.6 20.2±2.0
Ace ic anhyd ide 0.7±0.2 0.6±0.2
Ace ic acid 2.2±0.1 2.0±0.2
Fo mic acid 0.3±0.1 0.2±0.01
Fa y acids 11.5±2.5 12.1±4.0
Es e s (alkyl es e acids) 2.3±0.3 5.3±2.4
Ke ones 15.7±0.5 16.4±2.3
Ace one 2.4±0.1 2.2±1.0
1-Hyd oxy-p opanone 3.3±0.1 1.4±1.6
2,3-Bu anedione 1.2±0.1 1.6±0.3
Cyclohexanone 1.3±0.1 0.7±1.0
Py an de i a i es 0.45±0.1 0.4±0.1
O he s 7.0±0.3 10.1±0.1
Aldehydes 2.7±0.1 2.7±0.1
Phenols 2.8±0.1 3.8±1.4
1,2-Benzenediol - 1.0±0.3
3-Me hyl-1,2-benzenediol 0.8±0.4 0.6±0.3
Phenol 0.4±0.1 0.6±0.02
Phenol de i a i es 1.4±0.2 1.4±0.7
O he s 0.1±0.02 0.2±0.04
E he s 0.7±0.2 0.5±0.01
Alcohols 1.9±0.03 2.0±1.3
Lineal 1.7±0.05 1.3±0.7
Cyclic 0.2±0.02 0.8±0.5
Fu ans 9.6±0.9 14.4±0.5
Fu an de i a i es 3.5±0.2 3.6±0.7
Fu an de i a i es (ke ones) 0.7±0.1 0.7±0.04
Fu an de i a i es (aldehydes) 3.9±0.9 8.0±1.4
Fu u al 1.5±0.04 2.0±0.3
Anhyd osuga s 23.1±4.7 19.2±1.0
Le oglucosan 18.3±3.7 13.1±1.0
d-Allose 0.9±1.2 1.6±0.7
2,3-Anhyd o-d-mannosan 0.4±0.1 0.5±0.1
3,4-Anhyd o-d-galac osan 1.3±0.1 2.3±0.02
Dianhyd o glucopy anose 2.2±0.2 1.8±0.6
HC 0.3±0.1 0.3±0.1
Alipha ics 0.01±0.01 0.1±0.1
A oma ics 0.3±0.1 0.1±0.2
N compounds 0.3±0.02 0.3±0.1
Py ole 0.2±0.03 0.3±0.1
S compounds 0.6±0.1 0.4±0.01
Me hane hiol 0.6±0.1 0.2±0.3
Py ans 0.004±0.01 0.03±0.04
Non-iden i ied compounds 9.1±3.7 7.3±5.5
2805Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
Fig. 3 Ch oma og am ob ained
in he ca aly ic py olysis o DPS
on he HZSM-5 zeoli e a (a)
C/B=1, (b) C/B=2, and (c) C/
B=5, a T=450 °C
(a)
(b)
1
2
3
4
7
5
6
9
810 11
13 14
12
17
15 16
18
19
20
21
22
Iy isne n
Re en ion ime (min)
d
3
5
8
10
12
1314
c
15
g
22 23
20
21
19
1
2
a
24
h
y isne nI
Re en ion ime (min)
(c)
d
13
4
25
3
a
12
20
6
19
15
14
11
10
8
c
h
23
21
24
b
18
g
e
17
y isne nI
Re en ion ime (min)
2806 Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
C/B a io o 5 is used. This is a consequence o c acking,
deca bonyla ion, and deca boxyla ion eac ions p omo ed by
he HZSM-5 zeoli e due o i s acidi y (Si/Al=30).
The second mos abundan compound amily is he one o
hyd oca bons. This lump accoun s o a oma ic and non-a o-
ma ic compounds. The con en o non-a oma ic compounds
dec eases sligh ly om 1.2 o 0.7% when he B/C a io is
inc eased, whe eas ha o a oma ic compounds (p e ailing
ac ion in his lump) inc eases ma kedly om 5.9% when
he C/B a io is 1 o 23.8% when he C/B is 5. Toluene,
xylenes, naph halene de i a i es, and benzene de i a i es
a e he mos abundan compounds iden i ied. O he com-
pounds iden i ied a e indane, indene, luo ene, an h acene
and hei de i a i es, and biphenyl.
Figu e4 shows he peak a ea e olu ion o he whole a o-
ma ic amily, and o benzene, oluene, xylenes, and polya o-
ma ic hyd oca bons (PAH), when di e en ca alys /biomass
(C/B) mass a ios a e used. As obse ed, he a ea inc eases
when he C/B a io is inc eased, and especially when C/B=5
is used. This is he consequence o he eac ions a o ing
he o ma ion o a oma ic compounds, which a e enhanced
when a highe amoun o zeoli e is used.
Rega ding he PAH ac ion, he compounds iden i ied
a e naph halene, luo ene, an h acene, and hei de i a i es,
wi h naph halene and i s de i a i es being he mos abun-
dan ones.
This high concen a ion o hyd oca bon compounds is a
consequence o he deoxygena ion caused by he HZSM-5
Table 5 Re en ion imes,
compound names, and peak
a ea pe cen ages o he main
compounds ob ained in he
ca aly ic py olysis on he
HZSM-5 zeoli e (C/B=1, 2, 5)
a 450 °C
Peak a ea (%)
Peak numbe Re en ion
ime (min) Compound C/B=1 C/B=2 C/B=5
1 3.39 Ace aldehyde 0.76 1.17 3.14
2 4.0 Ace one 1.99 2.64 1.94
3 5.28 2,3-Bu anedione 0.84 0.81 0.32
4 5.65 Ace ic acid 0.83 0.6 0.04
5 6.74 1-Hyd oxy-2-p opanone 4.10 1.87 1.04
6 10.15 Ace ic acid, p opyl es e 0.65 - 0.12
7 10.72 P opanoic acid, 2-oxo, me hyl es e 0.46 0.18 0.08
8 11.18 Toluene 0.70 3.18 3.73
9 11.25 Ca bonocyanidic acid, e hyl es e 0.73 0.52 -
10 13.02 Fu u al 1.59 0.84 0.46
11 14.25 1-Ace yloxy-2-p opanone 1.73 0.23 0.12
a 15.21 E hylbenzene 0.19 0.67 0.72
12 15.66 p-Xylene 0.73 1.84 2.72
b 16.6 m-Xylene 0.09 0.24 0.40
13 16.93 2-Me hylcyclopen anone 1.09 0.54 0.30
14 18.73 5-Me hyl-2- u anca boxaldehyde 0.96 0.61 0.31
c 19.76 1,2,3-T ime hyl-benzene 0.66 1.01 0.91
d 21.1 1,2,4-T ime hyl-benzene 0.10 0.61 0.67
15 21.53 3-Me hyl-1,2-cyclopen anedione 1.30 0.60 0.32
16 28.46 1,2-Benzenediol 1.91 0.43 0.25
e 28.72 Naph halene 0.07 0.46 0.79
28.83 1-Me hyl-4-(1-me hyl-2-p openyl)-benzene - 1.93 -
17 28.92 5-(Hyd oxyme hyl)-2- u anca boxaldehyde 3.31 - 0.84
18 29.61 2,3-Anhyd o-d-mannosan 1.11 0.33 0.12
g 32.93 1-Me hyl-naph halene 0.24 1.49 1.28
19 37.49 Le oglucosan 13.51 8.73 2.55
h 36.85 2,3-Dime hyl-naph halene 0.61 0.79 0.70
20 38.59 d-Allose 1.86 0.88 0.15
21 41.51 Dodecanoic acid 6.05 7.91 1.53
22 47.28 Te adecanoic acid 2.88 0.78 0.08
23 48.39 An h acene - 0.53 0.43
24 51.6 9-Me hyl-an h acene 0.29 0.57 0.77
2807Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
zeoli e. Many au ho s ha e de e mined ha HZSM-5 zeo-
li es change he composi ion o he bio-oils by bo h educ-
ing he amoun o oxygena e compounds ia deoxygena ion
eac ions and inc easing he a oma ic species, which leads o
an o ganic ac ion (bio-oil) ha can be upg aded o gasoline
and diesel uels [10, 42, 43].
Ca lson e al. [44] de e mined ha he i s s age in cel-
lulose deg ada ion in ol es dehyd a ion eac ions o o m
anhyd osuga s, and hey subsequen ly unde go acid-ca a-
lyzed dehyd a ion on he ac i e si es o he ca alys , lead-
ing o he o ma ion o dehyd a ed p oduc s. These p od-
uc s unde go u he oligome iza ion, deca boxyla ion, and
deca bonyla ion, o c acking eac ions, o o m C2-C6 ole-
ins, which hen combine o yield a oma ics. The deoxygena-
ion leads o he p oduc ion o CO, CO2, and H2O.
Figu e5 shows he e olu ion o he con en o C3-C7 ole-
ins in he ca aly ic py olysis ca ied ou a 450 °C when he
C/B a ios o 1, 2, and 5 a e used. As obse ed, he con en
o he ligh e C3-C4 ole ins (p opene, 2-me hyl-p opene,
2-bu ene) inc eases ma kedly as he C/B a io is inc eased,
whe eas ha o C5-C7 ones (2-pen ene, 2-me hyl-1-bu ene,
3-hexene, 3-me hyl-1,3,5-hexa iene) goes h ough a sligh
Table 6 Mean peak a ea pe cen ages (95% con idence in e al) o
he di e en compound amilies ob ained in he ca aly ic py olysis o
DPS a 450 °C when he C/B mass a ios o 1, 2, and 5 a e used
The bold en ies signi icance is o emake he di e en amilies ca -
ego ies
Biomass/ca alys (B/C) mass a io
1/1 1/2 1/5
Incondensable gases 23.6±5.5 32.5±2.3 54.1±4.1
P opene 1.7±0.3 5.3±0.5 11.4±1.1
2-Me hyl-1-p opene 2.0±2.3 2.8±1.2 3.6±0.9
1-Bu ene - 1.6±0.6 1.3±0.3
Acids 11.7±2.3 11.4±3.3 2.4±0.2
Ace ic acid 1.1±0.2 1.0±0.5 0.2±0.2
Fa y acids 7.6±2.3 9.5±2.3 1.8±0.2
Es e s (alkyl es e acids) 2.6±0.02 1.0±0.1 0.4±0.2
Ke ones 14.8±3.2 8.6±1.1 5.4±0.8
Ace one 2.0±0.01 2.7±0.4 1.7±0.4
1-Hyd oxy-p opanone 3.6±0.7 1.9±0.3 0.8±0.3
2,3-Bu anodione 0.9±0.1 0.7±0.01 0.3±0.04
2-Bu anone 0.8±0.1 0.8±0.4 0.4±0.1
O he s 7.5±2.6 2.9±0.5 2.3±0.02
Aldehydes 1.5±0.5 1.7±0.2 3.2±0.4
Ace aldehyde 0.6±0.2 1.1±0.1 2.9±0.3
Phenols 3.3±1.2 1.2±0.5 0.7±0.04
1,2-Benzenediol 1.5±0.6 0.5±0.2 0.2±0.07
1,2-Benzenediol de i a i es 1.0±0.4 - 0.04±0.005
1,4-Benzenediol (hyd oquinone) - 0.2±0.01 0.06±0.08
1,4-Benzenediol de i a i es 0.2±0.03 0.1±0.1 0.02±0.03
Phenol 0.1±0.02 - 0.01±0.01
Phenol de i a i es 0.5±0.2 0.3±0.1 0.4±0.2
E he s 0.4±0.0 - 0.3±0.2
Alcohols 2.2±0.2 0.5±0.3 0.5±0.04
Lineals 1.9±0.2 0.5±0.3 0.4±0.07
Cyclics 0.2±0.1 - 0.02±0.02
Fu ans 7.4±1.4 3.6±0.8 1.9±1.3
Fu ane 0.4±0.1 0.7±0.1 0.3±0.1
Fu ane de i a i es 1.2±0.1 0.8±0.1 0.4±0.2
Fu ane de i a i es (ke ones) 0.7±0.2 0.4±0.05 0.2±0.2
Fu ane de i a i es (aldehydes) 3.7±0.8 0.7±0.2 0.7±0.6
Fu u al 1.4±0.3 1.0±0.3 0.3±0.2
Anhyd osuga s 18.0±1.9 8.7±7.1 2.5±0.6
Le oglucosane 15.1±2.3 7.8±6.7 2.2±0.5
d-Allose 1.9±0.004 0.5±0.4 0.2±0.03
2,3-Anhyd o-d-mannosan 0.9±0.3 0.4±0.1 0.1±0.04
2,3-Anhyd o-d-galac osan - - 0.03±0.04
Dianhyd o glucopy anose 0.2±0.1 0.1±0.03 0.06±0.002
Hyd oca bons 7.1±1.1 19.9±0.3 24.5±6.1
Alipha ics 1.2±0.5 1.5±0.4 0.7±0.3
A oma ics 5.9±0.6 18.3±0.7 23.8±6.4
N compounds 1.9±0.7 1.3±0.01 0.6±0.5
Ace oni ile 0.3±0.2 0.8±0.002 0.3±0.3
S compounds 0.1±0.2 2.1±0.01 2.0±0.1
Me hane hiol 0.1±0.2 2.1±0.01 2.0±0.1
Non-iden i ied compounds 8.1±0.2 8.2±1.0 1.7±1.6
0E+00
2E+07
4E+07
6E+07
o al a omacbenzene oluenexylenes PAH
Peak a ea
C/B=1C/B=2C/B=5
Fig. 4 E olu ion o he o al a oma ic con en and hose o benzene,
oluene, and xylenes o di e en ca alys /biomass a ios
0E+00
2E+07
4E+07
6E+07
C/B=1C/B=2 C/B=5
Peak a ea
C3-C4 C5-C7 o al (C3-C7)
Fig. 5 Dis ibu ion o C3-C7 ole ins in he ca aly ic py olysis a 450
°C o di e en ca alys /biomass a ios
2814 Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
by CaO as eac an ; ha is, he eac ion o CaO wi h acids
o o he ca boxyl g oups yields calcium ca boxyla es, which
a e subsequen ly decomposed in o CaCO3 and ke ones [65,
66]. Consequen ly, he ela i e con en o acids dec eases.
This can also explain he high ace one, 2,3-bu anedione, and
2-bu anone peak a eas ob ained.
O he compounds iden i ied in high pe cen ages a e
2-cyclopen en-1-one and de i a i es, cyclopen anone and
de i a i es, 1-(ace yloxy)-2-p opanone, and 2,3-pen anedi-
one. Zhou e al. [67] epo ed ha he signi ican o ma ion
o cyclic ke ones can be explained by he ans o ma ion
o anhyd osuga s (mainly le oglucosan) ia ea angemen
eac ions o u u yl ype compounds, such as u u al. O he
au ho s explained his phenomenon as ke oniza ion o ca -
bolic acids o o m ace one, which can couple wi h u ans o
ace one i sel ia aldol condensa ion o elonga e he ca bon
chain leng h by nume ous base ca alys s [68, 69]. The esul s
ob ained in his s udy show ha ke ones ha e a ma kedly
highe ela i e con en and u ans a signi ican dec ease
wi h espec o he alues ob ained in he he mal py olysis.
Besides, he con en o acids is lowe , especially o sho
ca bon chained ones, such as o mic and ace ic acids.
Valle e al. [23] upg aded he bio-oil on dolomi e and ob ained
a high amoun o ace one. They s a e ha his esul is e idence
o he dolomi e ac i i y o ace ic acid ke oniza ion and, u he -
mo e, o he ke oniza ion eac ions in ol ing ca boxylic acids
may also occu , which lead o he o ma ion o linea ke ones.
Anhyd osuga compounds a e he nex mos abundan
ones, wi h hei con en being 16.6%. Le oglucosan is he
p e ailing compound in his amily wi h a con en o 14.8%.
Incondensable gases accoun o a ela i e con en o 13.2%
and acids o 16.5%. In he acid amily, he long-chain acids
a e he main compounds iden i ied, e.g., undecanoic, hexa-
decanoic, and oc adecanoic acids, wi h hei con en s being
3.9, 3.5, and 2.0%, espec i ely.
The amilies made up o e he s and hyd oca bon com-
pounds a e also p oduced in a signi ican amoun (con en s
o 5.4% and 4.8%, espec i ely). Wi hin e he s, 1-me hoxy-
9-oc adecene and 1,1′-dime hoxy-9-oc adecene ha e been
iden i ied and accoun o 3.9 and 1.4%, espec i ely. The
hyd oca bon compounds a e C9-C18 alipha ic hyd oca bons
(pa a ins and ole ins). The a oma ic hyd oca bons iden i-
ied ha e been oluene, e hylbenzene, and 1,2,3- ime hyl-
benzene, wi h he i s one being he p e ailing one wi h a
con en o 0.2%.
Conce ning he deoxygena ing ac i i y o he dolomi e,
his ca alys lowe s he con en o oxygena ed compounds
om 98% (co esponding o he mal py olysis) o 93%,
unde he condi ions es ed (450 °C and a C/B a io o 1).
The e o e, i has a much lowe deoxygena ing capaci y han
he HZSM-5 zeoli e (83% o oxygena e compounds), which
is explained by he be e ea u es o he la e (acidi y and
po ous s uc u e) o his p ocess.
Table 10 Peak a ea pe cen ages o he di e en compound amilies
ob ained in he ca aly ic py olysis o DPS on dolomi e a 450 °C wi h
a C/B mass a io o 1
The bold en ies signi icance is o emake he di e en amilies ca -
ego ies
Peak a ea %
Incondensable gases 13.2±3.7
Acids 16.5±3.9
Ace ic acid 0.2±0.06
Fa y acids 12.9±3.7
Es e s (alkyl es e acids) 3.4±0.4
Ke ones 26.9±2.3
Ace one 2.7±0.8
1-Hyd oxy-p opanone 2.3±0.25
2,3-Bu anedione 1.5±0.1
2-Bu anone 1.3±0.6
O he s 19.0±1.5
Aldehydes 2.7±0.5
Ace aldehyde 1.3±0.4
Phenols 2.4±0.5
1,2-Benzenediol 0.6±0.3
1,2-Benzenediol de i a i es 0.1±0.08
Phenol 0.3±0.03
Phenol de i a i es 1.4±0.25
E he s 5.4±1.0
Es e s 0.8±0.1
Alcohols 1.7±0.1
Lineal 1.7±0.1
Cyclic 0.08±0.01
Fu an 3.2±1.2
Fu an de i a i es 0.3±0.03
Fu an de i a i es (ke ones) 0.4±0.1
Fu an de i a i es (aldehydes) 2.3±1.1
Fu u al 0.09±0.04
Anhyd osuga s 16.6±5.8
Le oglucosan 14.8±5.4
d-allose 0.25±0.2
2,3-Anhyd o-d-mannosan 0.2±0.05
3,4-Anhyd o-d-galac osan 0.6±0.15
Glucopy anose 0.1±0.02
O he s 0.6±0.5
HC 4.8±0.4
Alipha ics 4.5±0.4
A oma ics 0.25±0.03
N compounds 0.8±0.2
S compounds 0.7±0.2
Me hane hiol 0.7±0.2
Py ans 0.08±0.01
Non-iden i iedcompounds 4.5±2.2
2815Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
Compa ison o he mal and ca aly ic py olysis on HZSM‑5
and dolomi e Gi en ha he p oduc dis ibu ion ob ained
is e y di e en depending on whe he a ca alys is used o
no and on he ype o ca alys used, Fig.11 compa es he
p oduc dis ibu ions ob ained in he h ee si ua ions (wi h-
ou ca alys and on HZSM-5 and dolomi e ca alys ) a a C/B
a io o 1 and 450 °C.
As obse ed, he e a e signi ican di e ences in he peak
a ea pe cen ages o he p oduc amilies. Thus, a compa ison
o he esul s ob ained in he he mal py olysis and hose
ob ained on he dolomi e shows ha he e is a la ge inc ease
in he con en s o ke ones ( om 15.7 o 26.9%), e he s ( om
0.7 o 5.4%), and hyd oca bons ( om 0.4 o 4.8%) when
his ca alys is used, bu a signi ican dec ease in hose o
suga s ( om 23.1 o 16.6%), wi h le oglucosan being he
main compound, and specially u ans ( om 9.6 o 3.2%).
The lowe con en o le oglucosan on dolomi e o CaO has
also been de ec ed by o he au ho s [22, 70].
A compa ison o he esul s ob ained in he ca aly ic
py olysis on he dolomi e and HZSM-5 zeoli e shows ha
he majo di e ences a e he highe peak a ea pe cen ages
o incondensable gases, u ans, and hyd oca bons ob ained
on he HZSM-5 zeoli e. A oma ic hyd oca bons a e he
mos abundan ones on he HZSM-5 zeoli e, whe eas non-
a oma ic hyd oca bons a e he mos abundan ones on he
dolomi e. I is no ewo hy ha he dolomi e enhances he
o ma ion o e he s and especially o ke ones.
4 Conclusions
The HZSM-5 zeoli e is a sui able zeoli e o he deoxygena-
ion o he ola iles (bio-oil) gene a ed in he py olysis o
DPS biomass. This e ec has been obse ed especially a
450 °C wi h a high C/B mass a io (C/B =5) and leads o a
signi ican inc ease in he con en o incondensable gases
(especially C3-C4 ole ins) and a la ge inc ease in ha o a o-
ma ic hyd oca bons. The mos abundan compounds iden i-
ied a e benzene, oluene, xylenes, and polya oma ic hyd o-
ca bons, such as naph halene, luo ene, an h acene, and hei
de i a i es. Simul aneously, a signi ican educ ion in he
con en o acids, ke ones, u ans, and suga s has been de e -
mined, which is highe as he C/B a io is highe . The acids
and ke ones a e ela ed o he acidi y and ins abili y o he
bio-oil, and he e o e, he dec ease in hei con en imp o es
he quali y o he bio-oil. This deoxygena ing ac i i y o he
HZSM-5 zeoli e is due o i s p ope ies, such as acidi y and
po ous s uc u e (shape selec i i y), which p omo e c ack-
ing and deoxygena ion eac ions, and so he o ma ion o
a oma ic compounds.
In he case o he dolomi e ca alys , a low deoxygena -
ing ac i i y has been de e mined due o i s basic na u e and
low speci ic su ace a ea. The mos ema kable e ec o his
ca alys is he high con en o ke ones i allows ob aining.
This is he consequence o ke oniza ion eac ions in ol ing
ca boxylic acids, which a e p omo ed by he dolomi e ca a-
lys o gi e linea ke ones.
Acknowledgemen s The au ho s g a e ully acknowledge he Tunisian
Minis y o Highe Educa ion and Scien i ic Resea ch (MESRST), he
Spanish Minis y o Science and Inno a ion (PID2019-107357RB-I00)
(AEI/FEDER, UE), and he Basque Go e nmen (KK-2020/00107) o
hei inancial suppo .
Au ho con ibu ion MA, MO, and ABH designed he s udy. GB and
MB conduc ed he expe imen s and collec ed he da a. MA w o e he
d a o he manusc ip , while all o he co-au ho s p o ided subs an ial
eedback. All au ho s ga e inal app o al o publica ion.
Funding Open Access unding p o ided hanks o he CRUE-CSIC
ag eemen wi h Sp inge Na u e. This p ojec has ecei ed unding
om he Eu opean Union’s Ho izon 2020 esea ch and inno a ion
Fig. 11 Mean peak a ea pe -
cen ages ob ained in he mal
and ca aly ic py olysis (on
HZSM-5 and dolomi e, C/B=1)
a 450 °C
0
5
10
15
20
25
30
Peak a ea %
he mal zeoli e dolomi e
2816 Biomass Con e sion and Bio e ine y (2024) 14:2799–2818
1 3
p og amme unde he Ma ie Sklodowska-Cu ie g an ag eemen no.
823745.
Da a a ailabili y Da a and ma e ials suppo ing he conclusions o he
manusc ip a e a ailable om he co esponding au ho on easonable
eques .
Code a ailabili y No applicable
Decla a ions
Compe ing in e es s The au ho s decla e no compe ing in e es s.
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bu ion 4.0 In e na ional License, which pe mi s use, sha ing, adap a-
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Publishe ’s no e Sp inge Na u e emains neu al wi h ega d o
ju isdic ional claims in published maps and ins i u ional a ilia ions.
