CHEMICAL CHARACTERIZATION OF LIGNIN FROM ANNUAL PLANT GROWING IN NORTH OF ITALY

Size: px

Start display at page:

Download "CHEMICAL CHARACTERIZATION OF LIGNIN FROM ANNUAL PLANT GROWING IN NORTH OF ITALY"

Reynold Griffin
5 years ago
Views:

1 CHEMICAL CHARACTERIZATION OF LIGNIN FROM ANNUAL PLANT GROWING IN NORTH OF ITALY M. Orlandi 1, G. Elegir 2, F. Zanini 2, A. Salanti 1, E-L Tolppa, L. Zoia 1 1 Dipartimento di Scienze dell Ambiente e del Territorio, Università di Milano-Bicocca, Piazza della Scienza 1, Milano, Italy. 2 Stazione Sperimentale Carta Cartoni e Paste per la Carta, Piazza da Vinci, Milano, Italy.

2 WHERE ARE CULTIVATED IN ITALY RICE AND GIANT CANE

WHAT IS RICE HUSK? Rice is one of the most cultivated crops in the world with a global production of about 680 million tons/year). Italy produces approximately 1.

3 WHAT IS RICE HUSK? Rice is one of the most cultivated crops in the world with a global production of about 680 million tons/year). Italy produces approximately 1.4 million tons/year of rice, with the 90% of this production concentrated in the Northern Italy; Rice husk, the outer cover of rice grain, is among the principal processing side-products of the rice milling industry and accounts for about 20% by weight of rice; Rice husk does not possess a remarkable commercial interest and its price is very low (30-40 /ton in Italy; Because of the elevated ashes and lignin content, rice husk is not appropriate as animal feed raw material; Rice husk can be burnt under controlled conditions to obtain a large amount of silica.

4 PRELIMINARY RICE HUSK ANALYSIS Color Component % Water extractives 3,5 Ethanol extractives 1,2 Acid insoluble lignin 23,3 Acid soluble lignin 2,7 Ashes 16,8 Carbohydrates 52,6 Lignin: more than 20% Ashes: about 16%, constituted of around 85-90% amorphous silica Carbohydrates: about 52%

5 OUTLINE OF RICE HUSK PROJECT extractives A.O. activity

6 ANTIOXIDANT ACTIVITY OF EXTRACTIVES FROM RICE HUSK IC 50 (µg/ml) by DPPH radical scavenging activity AAC By B-carotene bleaching test Water extract Ethanol extract Acetone extract BHA reference

7 ENHANCED BIOGAS PRODUCTION AFTER LIGNIN REMOVAL The residual material, after lignin removal, was digested faster in anaerobic conditions in comparison to the untreated raw material

8 ANALYSIS PROTOCOL BENZOYLATION IL RICE HUSK KLASON LIGNIN GPC TGA LIGNIN EXTRACTION KLASON LIGNIN ACETYLATION PHOSPHORUS DERIVATIZATION GPC 2D-HSQC 31 P-NMR IL = 1-allyl-3-methylimidazolium chloride - [amim]cl

9 Benzoylation GPC characterization: NATIVE RICE HUSK CHARACTERIZATION Milling time (h) WPG (%) Benzoylated soluble fraction (%) , , , , , ,3 Particle size WPG More effective esterification (WPG) Solubilized rice husk fraction CELLULOSE / LIGNIN- CARBOHYDRATE COMPLEXES FREE LIGNIN Reduced milling time: mainly benzoylated lignin Higher milling time: enhanced benzoylated carbohydrate content 1,0E+07 1,0E+06 1,0E+05 1,0E+04 1,0E+03 1,0E+02 WPG = Weight Percentage Gain Molecular Weight (g/mol) 0h Ball Mill 15h Ball Mill 30h Ball Mill

10 LIGNIN EXTRACTION Acidolysis Lignin (AL). Dry, extratives-free (blended rice husk milled in a planetary ball mill for different periods of time at 300 rpm. Differently milled rice husk samples were refluxed under nitrogen for 2 hours in a 0.1 M HCl dioxane water solution (9:1) and then cool to room temperature. The insoluble material remained after lignin solubilization was collected by centrifugation The supernatant was added dropwise into a 0,01 M HCl aqueous solution which was then kept at + 4 C overnight to allow for a complete lignin precipitation Modified parameters: Milling Time (h) Alkali Enzyme Lignin (AEL). Mild alkaline cooking (5-10% solid consistency, M NaOH, 90 C, 4 hours) followed by Enzymatic hydrolysis (two-3 hours cycles with 50U/g of crude cellulase from Trichoderma reesei ATCC in 50 mm Na-acetate buffer ph5 at 40 C). Modified parameters: Temperature ( C), NaOH concentration

11 GEL PERMEATION CHROMATOGRAPHY: ACETYLATED SAMPLES 1,0E+06 1,0E+05 1,0E+04 1,0E+03 1,0E+02 Molecular Weight (g/mol) 0h Ball Mill 5h Ball Mill 10h Ball Mill 15h Ball Mill 20h Ball Mill 30h Ball Mill Milling time (h) M w (g/mol) M n (g/mol) M p (g/mol) I , , , ,8 SAME REPRESENTATIVITY , ,9 M n (number-average molecular weight, M w (weight-average molecular weight,

12 31 P-NMR QUANTIFICATION: Sample derivatization CH 3 H 3 C O C H 3 CH 3 H 3 C O P Cl + Lign OH O O H 3 C CH CH 3 3 Py, CDCl3 P O Lign DIFFERENTIATE: ALIPHATIC HYDROXYLS, DIFFERENTLY METHOXYLATED PHENOLS, ACIDIC GROUP 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane O N OH + phospholane INTERNAL STANDARD, QUANTITATIVE ANALYSIS O endo-n-hydroxy-5-norbornene-2,3-dicarboximide

13 Yields, purity, ashes content, average molecular weight indexes and labile hydroxyls composition of AL lignin extracted from differently milled rice husk samples.. Milling Time (h) Yield (%) Purity (Klason, %) > 85 > 85 > 85 > 85 > 85 > 85 Ashes (%) < 2 < 2 < 2 < 2 < 2 < 2 GPC (g/mol) M n M w M p I P NMR (mmol/g) Aliphatic -OH Cond. PhOH + S-OH G-OH P-OH COOH

14 Optimization of AEL extraction: effect of different reaction temperatures and NaOH concentrations on yields, purity, and morphological and chemical features. Reaction Temperature ( C) NaOH Concentration (M) Yield (%) Purity (Klason, %) Ashes (%) < 2 < 2 < 2 < 2 < 2 < 2 GPC (g/mol) M n M w M p I P NMR (mmol/g) Aliphatic -OH Cond. PhOH + S-OH G-OH P-OH COOH If not otherwise indicated: reaction period, concentration of soda and reaction temperature set at 4 h, 0.2 M, and 90 C.

15 CONCLUSIONS ABOUT THE AEL EXTRACTION The parameters chooses for AEL extraction from rice husk were 4 h, 90 C, 0.3M NaOH as a compromise between Yield Purity Oxidative conditions

16 Comparison among yields, compositional evaluation, and morphological and chemical features of rice husk lignin specimens by gravimetric, GPC and 31 P NMR analyses. AL AEL Milling time (h) 20 blended Yield (%) Purity (Klason, %) Ashes (%) < 2 < 2 Carbohydrate (%) GPC (g/mol) M n M w M p I P NMR (mmol/g) Aliphatic -OH Cond. PhOH + S-OH G-OH P-OH COOH

17 COMPARISON AMONG 31 P NMR SPECTRA OF AL AND AEL SAMPLES IS ALIPH. -OH COND. OH G-OH P-OH COOH + S-OH AL AEL ppm

18 Ester bonds on wheat straw lignin terminal units Crestini C.; Argyropoulos D.S. Structural Analysis of Wheat Straw Lignin by Quantitative 31 P and 2D NMR Spectroscopy. The Occurrence of Ester Bonds and β-o-4 Substructures. J. Agric. Food Chem. 1997, 45,

19 2D-HSQC-NMR SPECTRA OF ACETYLATED AL AND AEL SAMPLES FROM RICE HUSK AL S-OH α β-o-4 α β-5 β β-o-4 γ -OCH 3 AEL S-OH α β-o-4 α β-5 β β-o-4 γ -OCH 3 γ β-β G-OH G-OH H-OH H-OH (β-o-4) (β-5) (β-β)

20 2D HSQC SPECTRUM OF AL ACETYLATED LIGNIN SAMPLE FROM RICE HUSK: INTERMONOMERIC BONDS AREA AL -OCH 3 γ (β-o-4, β-5) α (β-o-4) β (β-o-4) α (β-5)

21 2D HSQC SPECTRUM OF AEL ACETYLATED LIGNIN SAMPLE FROM RICE HUSK: INTERMONOMERIC BONDS AREA AEL α (β-o-4) γ (β-β) β) β (β-o-4) α (β-5)

22 CONCLUSIONS husk lignin is mainly formed by guaiacyl and p-hydroxyphenyl units, not depending by the applied extraction procedure, and by β-o-4 and β-5 intermonomeric bonds AEL sample is characterized by a molecular weight distribution shifted toward higher molecular weight AEL sample is contaminated by the presence of residual carbohydrate AEL sample has lower amount of free phenolic groups In AEL lignin there are lignin-carbohydrate bond that the alkaline treatment is not able to cleave.

23 TGA/DTG OF RICE HUSK ACIDOLYSIS LIGNIN (AL)

24 TGA/DTG OF RICE HUSK ENZYMATIC ALKALINE LIGNIN (EAL) T1% 160 C T5% 225 C RES N2 32,5% 321 C

25 ANTIOXIDANT ACTIVITY OF RICE HUSK IC 50 (µg/ml) by DPPH radical scavenging activity AAC By B-carotene bleaching test Water extract Ethanol extract Acetone extract AEL total 92.4 N.D AEL > 10kDa N.D AEL < 10kDa BHA reference

strong candidate for use as a renewable biofuel source because of its fast

26 What is Arundo donax (Giant Cane) Arundo donax is a tall perennial cane growing in damp soils, either fresh or moderately saline Arundo donax is strong candidate for use as a renewable biofuel source because of its fast growth rate, ability to grow in different soil types and climatic conditions.

27 Comparison among yields, compositional evaluation, and morphological and chemical features of rice husk, Arundo donax and Wheat straw RH AD WS Klason Lignin, % Ashes, % Extractives, % Carbohydrates, % Lignin Milling Time (h) 20 blended blended Yield, % Purity, % (Klason) 86.0 > 85 > 85

28 Comparison among yields, compositional evaluation, and morphological and chemical features of rice husk, Arundo donax and wheat straw lignins, specimens by, GPC and 31 P NMR analyses RH AD WS GPC (g/mol) M n M w M p I P NMR (mmol/g) Aliphatic -OH Cond. PhOH + S-OH G-OH P-OH COOH

29 ACKNOWLEDGMENTS Fondazione Cariplo for financial support of the project (Lignoplast ) Dr. Maurizio Canetti and Dr. Fabio Bertini ISMAC CNR Milan ITALY Diego Sidari Dr. Michelle Marrone University of Milan-Bicocca Chemtex Italy srl

New Insights into Eucalyptus Lignin & Pulping Chemistry

New Insights into Eucalyptus Lignin & Pulping Chemistry Anderson Guerra, Ilari Filpponen, Lucian A. Lucia and Dimitris S. Argyropoulos rganic Chemistry of Wood Components Laboratory Department of Forest