Membrane Filtration of Agro industrial Wastewaters and Isolation of - PowerPoint PPT Presentation

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

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

Physicochemical Separation Techniques • Solid ‐ liquid extraction is the separation of target compounds from a solid matrix through the use of the appropriate solvent. • Membrane filtration is a separation technique that has many applications in chemical process industries. • Adsorption is the selective separation of a solute (adsorbate) from a mixture, which is concentrated on the surface of a solid (adsorbent). • Vacuum Evaporation for the final condensation of the isolated compounds 4 Membrane Filtration of Agro ‐ industrial Wastewaters and Isolation of Organic Compounds with High Added Value 29/6/2016

Olive Mill Wastewater Phenolic Compounds • Olive mill wastewater (OMW) is a byproduct of the three ‐ phase extraction systems during the production of olive oil. • Because of their partition coefficient, most phenolic compounds of olive fruits Oleuropein end up in the wastewater produced and not in olive oil. • Oleuropein is the most common phenolic compound of unripe olive Hydroxytyrosol fruits, but during maturity it is hydrolyzed to several simpler phenolic compounds like hydroxytyrosol and tyrosol. Tyrosol 5 Membrane Filtration of Agro ‐ industrial Wastewaters and Isolation of Organic Compounds with High Added Value 29/6/2016

Membrane Filtration of OMW Sieving Initial UF UF NF NF RO RO [g/L] <0.125 OMW Conc. Filtr. Conc. Filtr. Conc. Filtr. mm 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 6 Membrane Filtration of Agro ‐ industrial Wastewaters and Isolation of Organic Compounds with High Added Value 29/6/2016

Resin Adsorption/Desorption of OMW RO c 100 100 100 Carbohydrates 100 100 100 XAD4 Carbohydrates Phenols XAD4 12 rv/h Ph Phenols XAD7HP 6 rv/h Ph XAD7HP % Carbohydrates Adsorbed 80 80 80 XAD16N 3 rv/h Ph 80 80 80 XAD16N % Desorption with ethanol % Phenols Adsorbed 12 rv/h Ch % Desorption with water 6 rv/h Ch % Desorption 3 rv/h Ch % Adsorption 60 60 60 60 60 60 40 40 40 40 40 40 20 20 20 20 20 20 Carbohydrates Phenols 0 0 0 0 0 0 2 4 0 6 20 8 40 10 60 12 80 100 120 0 2 4 0 6 20 8 40 10 60 12 80 100 120 0 1 2 3 4 5 6 0 Filtrated Volume (rv) g of Resin/L of Sample g of Resin/L of Sample Filtrated Volume (rv) Filtrated Volume (rv) Triple Distilled Water Ethanol Acetone (a) (a) (b) (b) (c) Solvent • XAD4 and XAD16N yielded the best results. Even though the sample contained more carbohydrates than phenols, 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 the resin was desorbed at a high percentage (60%). Ethanol, on the other hand, almost selectively removed the adsorbed phenols, while acetone removed both, carbohydrates and phenols. • Kinetic experiments allowed the optimization of flow rates and total volume of treated sample before the resin surface was saturated. 7 7 29/6/2016 29/6/2016 Membrane Filtration of Agro ‐ industrial Wastewaters and Isolation of Organic Compounds with High Added Value ΔΙΑΧΩΡΙΣΜΟΣ , ΑΠΟΜΟΝΩΣΗ ΚΑΙ ΕΜΠΛΟΥΤΙΣΜΟΣ ΦΑΙΝΟΛΙΚΩΝ ΕΝΩΣΕΩΝ ΑΠΟ ΑΓΡΟΤΙΚΑ ΠΑΡΑΠΡΟΙΟΝΤΑ ΜΕ ΦΥΣΙΚΟΧΗΜΙΚΕΣ ΜΕΘΟΔΟΥΣ

Final Concentrate of OMW Phenolic Compounds • After carbohydrates removal via the proposed resin process, the distillation under vacuum ( ‐ 0.95 bar, 55 °C) of the resin ethanolic effluent resulted to a final phenol concentration of 378 g/L in gallic acid equivalents in the distillation residue. 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 8 Membrane Filtration of Agro ‐ industrial Wastewaters and Isolation of Organic Compounds with High Added Value 29/6/2016

HPLC Analysis of Simple Phenols Phenolic compound Desorbed From UF feed UF Filtr. UF Conc. NF Filtr. NF Conc. RO Conc. Evap. Resin (mg/L) 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 the low ‐ molecular ‐ weight phenols through sieving of all the compounds according to their molecular weight. • The resin process further purified the phenols from the rest of the low ‐ molecular ‐ weight compounds according to their polarity. • After vacuum distillation, the phenolic compounds appear to withstand the heat process and the final concentration of HT obtained in the distillation concentrate is around 85 g/L. 9 Membrane Filtration of Agro ‐ industrial Wastewaters and Isolation of Organic Compounds with High Added Value 29/6/2016

Grape Marc Phenolic Compound • Grape cultivation is one of the most important agricultural activities in the world with most of the produced grapes used in winemaking. Catechin • In the winemaking process a significant amount of solid byproducts is produced originating Epicatechin from the skin and seeds of grapes after the juice extraction. • Although part of the phenolic content of the grapes is transferred to the juice and later trans ‐ Resveratrol wine, the solid byproducts are rich in phenols, allowing the production of phenol ‐ rich extracts Quercetin 10 Membrane Filtration of Agro ‐ industrial Wastewaters and Isolation of Organic Compounds with High Added Value 29/6/2016

Extraction of Grape Marc Phenolic Compounds Phenols Phenols Carbohydrates Carbohydrates 3500 3500 3000 3000 Extracted compound (mg/L) Extracted compound (mg/L) 2500 2500 2000 2000 Optimum extraction conditions 1500 1500 1000 1000 Ethanol % 50 500 500 HCl 1N % 1 0 0 0 20 40 60 80 100 0 1 2 3 4 5 HCl 1N (%) Ethanol % (v/v) Duration 15 min (a) (b) Phenols Phenols Carbohydrates Carbohydrates Solids/Solvent 200 g/L 3500 3500 Extracted compound (mg/L) 3000 Extracted compound (mg/L) 3000 Double extraction 2500 2500 2000 2000 1500 1500 1000 1000 500 500 0 0 10 20 30 40 50 60 70 80 90 100 50 100 150 200 250 300 Time (min) Solid (g/L) (c) (d) 11 Membrane Filtration of Agro ‐ industrial Wastewaters and Isolation of Organic Compounds with High Added Value 29/6/2016

Membrane Filtration of Grape Marc Extract • 20 kg of grape marc were extracted, with 50 L of extract occurring. • Prior to membrane filtration, the extract was sieved through stainless steel sieves with mg/L final pore diameter 0.125 mm. and ethanol Initial UFc UFf NFc NFf Volume Total Sample Total was partly removed through distillation L Catechin Quercetin Epicatechin Rutin carbohydrates phenols leading to 15 L of residue with 14% v/v ethanol (compared to 50% v/v). The extract Initial 80 2204 440 7.4 <1 1.8 1.4 was then diluted with water to 80 L. UF f 60 1106 285 9.1 <1 2.1 1.8 NF c 15 1882 743 15.6 <1 2.3 3.0 NF f 45 443 23 3.8 <1 1.7 N/D 12 Membrane Filtration of Agro ‐ industrial Wastewaters and Isolation of Organic Compounds with High Added Value 29/6/2016