Membrane Filtration of Agro and of Organic with High Addeduest.ntua.gr/cyprus2016/proceedings/presentation/5.c_a... · 2016-06-29 · Membrane Filtration of Agro‐ industrial Wastewaters

Membrane Filtration of Agro‐industrial Wastewaters and Isolation of Organic Compounds with High Added Value

D.P. Zagklis, and C.A. Paraskeva, Department of Chemical Engineering, University of Patras

Presentation Outline

•Purification of olive mill wastewater phenols•Purification of grape marc phenols•Purification of olive leaf phenols•Preliminary design of phenols purification plant

29/6/2016 Membrane Filtration of Agro‐industrial Wastewaters and Isolation of Organic Compounds with High Added Value2

Scope• Large amounts of agricultural byproducts are produced every year, some of them rich in phenolic compounds.

• Phenols are antioxidants with high‐added value and positive effects to the human health.

• Their separation for the production of cosmetic products, food supplements etc., is of great interest.

• For this purpose, a combination of solid‐liquid extraction, membrane filtration and resin adsorption/desorption following by evaporation is proposed, for the production of phenolic concentrates.

• The final products of the proposed process contain a large percentage of the byproducts’ phenolic content, in a small fraction of the initial volume.

• This technique, after modification, can be applied to a variety of phenol‐rich byproducts, allowing the operation of phenol separation plant adjustable to local agricultural activities.


Physicochemical Separation Techniques


• Solid‐liquid extraction is the separation of target compoundsfrom a solid matrix through the use of the appropriate solvent.

• Membrane filtration is a separation technique that has manyapplications in chemical process industries.

• Adsorption is the selective separation of a solute (adsorbate) froma mixture, which is concentrated on the surface of a solid(adsorbent).

• Vacuum Evaporation for the final condensation of the isolatedcompounds

Olive Mill Wastewater Phenolic Compounds• Olive mill wastewater (OMW) is abyproduct of the three‐phase extractionsystems during the production of oliveoil.

• Because of their partition coefficient,most phenolic compounds of olive fruitsend up in the wastewater produced andnot in olive oil.

• Oleuropein is the most commonphenolic compound of unripe olivefruits, but during maturity it ishydrolyzed to several simpler phenoliccompounds like hydroxytyrosol andtyrosol.


Oleuropein

Hydroxytyrosol

Tyrosol

Membrane Filtration of OMW

[g/L] Initial OMW

Sieving <0.125 mm

UF Conc.

UF Filtr.

NF Conc.

NF Filtr.

RO Conc.

RO Filtr.

COD 107.23 99.08 257.73 51.10 61.03 32.72 65.48 6.47

TS 63.4 58.8 121.36 37.35 43.82 22.15 60.44 1.48

TSS 44 33 141 1.33 1.77 0.95 1.67 0.08

Ch 12.34 13.19 19.37 10.93 11.97 5.09 14.96 0.21

Ph 2.64 2.65 6.59 2.17 2.64 0.86 2.09 0.04



Resin Adsorption/Desorption of OMW ROc

• XAD4 and XAD16N yielded the best results. Even though the sample contained more carbohydrates thanphenols, resins adsorbed the dissolved phenols at a higher percentage.

• When water was used as a desorption solvent, the small amount of carbohydrates that was adsorbed on theresin was desorbed at a high percentage (60%). Ethanol, on the other hand, almost selectively removed theadsorbed phenols, while acetone removed both, carbohydrates and phenols.

• Kinetic experiments allowed the optimization of flow rates and total volume of treated sample before theresin surface was saturated.

29/6/2016 ΔΙΑΧΩΡΙΣΜΟΣ, ΑΠΟΜΟΝΩΣΗ ΚΑΙ ΕΜΠΛΟΥΤΙΣΜΟΣ ΦΑΙΝΟΛΙΚΩΝ ΕΝΩΣΕΩΝ ΑΠΟ ΑΓΡΟΤΙΚΑ ΠΑΡΑΠΡΟΙΟΝΤΑ ΜΕ ΦΥΣΙΚΟΧΗΜΙΚΕΣ ΜΕΘΟΔΟΥΣ7

0 20 40 60 80 100 1200

20

40

60

80

100

XAD4 XAD7HP XAD16N

% P

heno

ls A

dsor

bed

g of Resin/L of Sample(a)

0 20 40 60 80 100 1200

20

40

60

80

100

XAD4 XAD7HP XAD16N

% C

arbo

hydr

ates

Ads

orbe

d

g of Resin/L of Sample(b)

Triple Distilled Water Ethanol Acetone0

20

40

60

80

100

Carbohydrates Phenols

% D

esor

ptio

n

Solvent

0 2 4 6 8 10 120

20

40

60

80

100

12 rv/h Ph 6 rv/h Ph 3 rv/h Ph 12 rv/h Ch 6 rv/h Ch 3 rv/h Ch

% A

dsor

ptio

n

Filtrated Volume (rv)(a)

0 2 4 6 8 10 120

20

40

60

80

100


% D

esor

ptio

n w

ith w

ater

Filtrated Volume (rv)(b)

0 1 2 3 4 5 60

20

40

60

80

100


% D

esor

ptio

n w

ith e

than

ol

Filtrated Volume (rv)(c)

Final Concentrate of OMW Phenolic Compounds

Initial OMW RO concentrate Ethanolic resin effluent Distillation residue

Volume, mL 16700 2000 1500 9

Phenols, g/L 2.64 ±0.04 2.09 ±0.02 2.36 ±0.01 377.50 ±8.34

Carbohydrates, g/L 12.34 ±0.49 14.96 ±0.03 3.84 ±0.01 293.92 ±1.28


• After carbohydrates removal via theproposed resin process, the distillationunder vacuum (‐0.95 bar, 55 °C) of theresin ethanolic effluent resulted to a finalphenol concentration of 378 g/L in gallicacid equivalents in the distillation residue.

HPLC Analysis of Simple Phenols

Phenolic compound

(mg/L)UF feed UF Filtr. UF Conc. NF Filtr. NF Conc. RO Conc.

Desorbed From

ResinEvap.

Gallic acid 29.5 32.1 36.4 19.5 48.5 42.9 75.9 5908

Hydroxytyrosol 75.4 259.5 98.4 246.4 377.2 558.9 974 84775

Tyrosol 38.16 60.8 23.6 64.8 65.1 136 152.2 21072


• The only phenolic compounds detected out of the ones tested were gallic acid,hydroxytyrosol (HT) and tyrosol with HT being the dominant phenol.

• No phenols were in detectable levels in the RO filtrate. The membrane process purified thelow‐molecular‐weight phenols through sieving of all the compounds according to theirmolecular weight.

• The resin process further purified the phenols from the rest of the low‐molecular‐weightcompounds according to their polarity.

• After vacuum distillation, the phenolic compounds appear to withstand the heat processand the final concentration of HT obtained in the distillation concentrate is around 85 g/L.

Grape Marc Phenolic Compound• Grape cultivation is one of themost important agriculturalactivities in the world with most ofthe produced grapes used inwinemaking.

• In the winemaking process asignificant amount of solidbyproducts is produced originatingfrom the skin and seeds of grapesafter the juice extraction.

• Although part of the phenoliccontent of the grapes istransferred to the juice and laterwine, the solid byproducts are richin phenols, allowing the productionof phenol‐rich extracts


Catechin

Epicatechin

trans‐Resveratrol

Quercetin

Extraction of Grape Marc Phenolic Compounds


0 20 40 60 80 1000

500

1000

1500

2000

2500

3000

3500

Phenols Carbohydrates

Extra

cted

com

poun

d (m

g/L)

Ethanol % (v/v)(a)

0 1 2 3 4 50

500

1000

1500

2000

2500

3000

3500

Extra

cted

com

poun

d (m

g/L)

HCl 1N (%)(b)


10 20 30 40 50 60 70 80 90 1000

500

1000

1500

2000

2500

3000

3500

Extra

cted

com

poun

d (m

g/L)

Time (min)(c)


50 100 150 200 250 3000

500

1000

1500

2000

2500

3000

3500


Extra

cted

com

poun

d (m

g/L)

Solid (g/L)(d)

Optimum extraction conditions

Ethanol % 50

HCl 1N % 1

Duration 15 min

Solids/Solvent 200 g/L

Double extraction

Membrane Filtration of Grape Marc Extract

Sample VolumeL

mg/L

Total carbohydrates

Total phenols

Catechin Quercetin Epicatechin Rutin

Initial 80 2204 440 7.4 <1 1.8 1.4

UFf 60 1106 285 9.1 <1 2.1 1.8

NFc 15 1882 743 15.6 <1 2.3 3.0

NFf 45 443 23 3.8 <1 1.7 N/D


Initial UFc UFf NFc NFf

• 20 kg of grape marc were extracted, with 50L of extract occurring.

• Prior to membrane filtration, the extract wassieved through stainless steel sieves withfinal pore diameter 0.125 mm. and ethanolwas partly removed through distillationleading to 15 L of residue with 14% v/vethanol (compared to 50% v/v). The extractwas then diluted with water to 80 L.

Final Concentration of Grape Marc Phenolic Compounds

Sample VolumemL*

mg/LTotal

carbohydrates Total phenols Catechin Quercetin Epicatechin Rutin

Desorbed 4000 1951 3023 65.0 <1 13.0 31.0

Evap. 31 112333 190850 4746 60 853 381


FinalConcentrate

* The resin process was not applied in all of the NFc, the volumes presented occurred after scaling of the results.

• With the removal of carbohydrates from theNFc, further concentration can be achievedthrough evaporation. For this purpose 2.4 Lof NFc were treated with the proposed resinprocess, leading to the production of 0.64 Lof ethanolic effluent that was evaporatedunder vacuum (0.05 bar, 50 °C). The finalconcentrate had a volume of 5 mL.

Olive Leaf Phenolic Compounds• Olive leaves are a byproduct ofolive fruit harvesting and initialstages of olive oil extraction,during their separation from olivefruits.

• Olive leaf extracts have beenproven to be rich in phenoliccompounds, with the mostprominent one being oleuropein,which, unlike in the olive fruit, it isnot hydrolyzed to simpler phenols.

• Oleuropein can be either bound toa sugar molecule (Oleuropeinglycoside) or be present in its freeform (Oleuropein aglycon).


Oleuropein

Extraction of Olive Leaf Phenols


0 25 50 75 1000

500

1000

1500

2000

2500

3000

Extra

cted

com

poun

d (m

g/L)

Ethanol (% v/v)(a)

PhenolsCarbohydrates

50 100 150 200 2500

1000

2000

3000

4000

5000

Extra

tced

com

poun

d (m

g/L)

Solids (g/L)(b)


0 30 60 90 120 150 180 2100

2000

4000

6000

8000

10000

Extra

cted

com

poun

d (m

g/L)

Time (min)(c)


Optimum extraction conditions

Ethanol % 0

Duration 120 min

Solids/Solvent 250 g/L

Membrane Filtration of Olive Leaf Extract

Initial UF conc. UF filtr. NF conc. NF filtr. Volume L 75 17 58 9 49Total Ph mg/L 468 ±15 774 ±3 325 ±7 988 ±25 88 ±1 Total Ch mg/L 2801 ±30 3458 ±27 2140 ±179 5410 ±37 1249 ±24


Resin Adsorption/Desorption of Olive Leaf Extract NFc

• All three resins appeared to adsorb the phenols contained in the NF concentrate to anacceptable extend, but, on the other hand, significant adsorption of carbohydratestook place as well.

• The high adsorption percentage of carbohydrates, indicate the presence of complexcompounds, like phenol glycosides, which can be detected as phenols andcarbohydrates.


0 20 40 60 80 100 120 140 160 180 200

0

20

40

60

80

100

XAD4 XAD7HP XAD16N

% C

arbo

hydr

ate

adso

rptio

n

Resin (g/L)0 20 40 60 80 100 120 140 160 180 200

0

20

40

60

80

100

XAD4 XAD7HP XAD16N

% P

heno

ls a

dsor

ptio

n

Resin (g/L)

2 3 4 5 6 7 8 9 100

20

40

60

80

100

Ph 5 rv/h Ph 10 rv/h Ph 20 rv/h Ph 50 rv/h Ch 5 rv/h Ch 10 rv/h Ch 20 rv/h Ch 50 rv/h

% A

dsor

bed

Filtrated Volume (resin volume)

0 1 2 3 4 5 60

10

20

30

40

50

60

70

80

90

100


% D

esor

bed

with

wat

er

Filtrated volume (rv)0 1 2 3 4 5 6

0

10

20

30

40

50

60

70

80

90

100


% D

esor

bed

with

eth

anol

Filtrated volume (rv)

Final Concentration of Olive Leaf Phenols

Volume mL Total Phenolsmg/L

Total Carbohydrates mg/L

NFc 1440 988 ±25 5410 ±37Desorbed 720 1480 ±1 5260 ±35Final concentrate 10 97890 ±1230 322333 ±3933

29/6/2016 Membrane Filtration of Agro-industrial Wastewaters and Isolation of Organic Compounds with High Added Value18

• 1.44 L of NF concentrate were treated withthe proposed resin process, leading to theproduction of 0.72 L of ethanolic effluentthat was evaporated under vacuum (0.05bar, 50 °C). The final concentrate had avolume of 10 mL .

Oleuropein‐glycoside


β‐glycosidase

+

+esterase

Glucose

HydroxytyrosolOleuropein

Elenoic acid

Hydroxytyrosol

Elenoic acid

Olive Leaf Extract‐Conclusions• With the proposed method, significant separation of olive leaf phenols was achieved.Firstly optimization of the extraction conditions was carried out, in terms of solventethanol percentage, solid/solvent ratio and duration.

• 20 kg of olive leaves were extracted with 80 L of water, and the extract was treatedwith membrane filtration. In the UF step, the suspended particles were removed,while NF concentrated the majority of the contained phenolic compounds.

• With batch adsorption experiments, XAD16N was proven to have the best adsorptionbehavior, and was used in resin packed beds to treat a larger amount of NFconcentrate. The occurring resin ethanolic product contained 65% of the NFconcentrate phenols and 23% of the contained carbohydrates.

• The ethanolic product of the resin process was finally treated with vacuumevaporation, with the finally product containing around 98 g/L phenolic compounds ingallic acid equivalents, compared to 0.5 g/L of the initial extract.

• This separation, although significant, was affected by the presence of complexphenolic compounds, like oleuropein‐glycoside, part phenols and part carbohydrates.


Phenols Purification Plant• The combination of solid‐liquid extraction, membrane filtration andresin adsorption/desorption could be modified and applied to a varietyof byproducts rich in phenolic compounds.

• The seasonal nature of these byproducts makes the combination ofdifferent byproducts imperative for the continuous operation of theplant.

• The viability of this endeavor strongly depends on the market demandof the high‐added value phenolic products and the management of thehigh volumes of byproducts occurring from the proposed process.

• A preliminary design of such a plant was carried out, based on theresults obtained from the treatment of olive mill wastewater.


Preliminary Design of Phenols Purification Plant


300 m3

100 m3 100 m3 100 m3

100 m3

50 m3

100 m3

Initial waste storage tank(1)

Solids tank(2)

Pretreated waste tank (7)

Oil tank(3)

Decanter feed tank

(4)

vertical separator feed tank

(5)

filter press feed tank

(6)

100 m3

UF feed tank (8)

200 m3

UF concentrate tank (18)

Pretreatment Plant byproduct treatment capacity: 110 tn/h (2000 tn/d)



100 m3

UF filtrate tank (9)

100 m3

NF filtrate tank (11)

200 m3

RO filtrate tank (13)

UF

NF

RO

50 m3RO

concentrate tank (14)

100 m3

100 m3

100 m3

50 m3

Not adsorbed and water

desorbed tank (15)

Water

Ethanol 95%

Ethanoliceffluent tank (16)

1 m3 Final concentrate tank (17)

100 m3

NF feed tank (10)

100 m3

RO feed tank (12)

250 m3

NF concentrate tank (19)


Source Main product Harvesting period

Tomato byproducts Quercetin, Hydroxycinnamic acids and lycopene May-August

Coffee byproducts Hydroxycinnamic acids All year

Citrus byproducts Hesperidin November-March

Apple, pear byproducts Hydroxycinnamic acids September-January

Strawberry byproducts Anthocyanins May-July

Mediterranean aromatic plants (dyctamus, marjoram, vitex, teucrium, rosemary) Phenolic acids June-August


General Conclusions• Solid‐liquid extraction, membrane filtration and resin adsorption/desorptionwere combined for the purification of phenols contained in olive millwastewater, grapemarc and olive leaves.

• For the solid materials examined, correct extraction was crucial formaximizing the phenolic concentration. Moreover, pretreatment of thesamples can greatly affect the results, as for example reduction of olive leafparticle size may increase the amount of phenols extracted, with lowerextraction durations, or defatting of cocoa powder can prevent the hindrancethat was exhibited due to high fat percentage.

• During membrane filtration, the extracted compounds were fractionatedaccording to their molecular weight. In the UF step, the solids contained in thesamples were removed. The complex and higher molecular weightcompounds were concentrated in the NF step, while low molecular weight atthe RO step.


General Conclusions• After the selective adsorption of the phenolic compounds of the membraneconcentrate of interest, water was used to desorb the adsorbed carbohydratesand ethanol for the desorption of phenols.

• During the resin process, the solvent of the phenolic compounds was changedfrom water to ethanol, facilitating their further concentration throughevaporation. The final product of the proposed process contains a largeamount of the phenols contained in the initial plant material, in a very smallfraction of the initial volume

• Apart from the plant materials examined in this study, the proposed processcan be employed for the treatment of any material rich in phenoliccompounds. A preliminary design of a treatment plant was presented, thatcan be adjusted for the extraction of phenols from regional agro‐industrialbyproducts, with some phenol‐rich byproduct proposals as well.


I would like to thank:Prof. P. Koutsoukos

Dimitris Zagklis, Ph.D

I. Iakovides, Ph.D student

A. Pantziaros, Graduate Student

E. Pavlakou, Graduate Student

Spyros Kontos, Ph.D studentLaboratory ofTransport Phenomena and Physicochemical Hydrodynamics



References

29/6/201628

Dimitris P. Zagklis, PhD Dissertation, ‘Separation, isolation and enrichment of phenolic compounds from agricultural byproducts with physicochemical methods’, November 2, 2015, Patras

D. P. Zagklis & C. A. Paraskeva, “Purification of grape marc phenolic compounds through solvent extraction, membrane filtration and resin adsorption/desorption”, Separation and Purification Technology, 156 (2015), 328-335

D. P. Zagklis, A. I. Vavouraki, M. E. Kornaros & C. A. Paraskeva, “Purification of olive mill wastewater phenols through membrane filtration and resin adsorption/desorption”, J. Hazard. Mater. 285 (2015) 69-76.

D. P. Zagklis & C. A. Paraskeva, "Membrane filtration of agro-industrial wastewaters and isolation of organic compounds with high added values", Water Sci. Technol. 2014, 69(1), 202-207.

Documents

Membrane Filtration of Agro and of Organic with High Addeduest.ntua.gr/cyprus2016/proceedings/presentation/5.c_a... · 2016-06-29 · Membrane Filtration of Agro‐ industrial Wastewaters