Research

21 pages, 7295 KiB

Open AccessArticle

Catalytic Depolymerization of Date Palm Waste to Valuable C5–C12 Compounds

by Emmanuel Galiwango, Ali H. Al-Marzuoqi, Abbas A. Khaleel and Mahdi M. Abu-Omar

Catalysts 2021, 11(3), 371; https://doi.org/10.3390/catal11030371 - 12 Mar 2021

Cited by 2 | Viewed by 2305

Lignin depolymerization often requires multiple isolation steps to convert a lignocellulose matrix into high-value chemicals. In addition, lignin structural modification, low yields, and poor product characteristics remain challenges. Direct catalytic depolymerization of lignocellulose from date palm biomass was investigated. Production of high value [...] Read more.

Lignin depolymerization often requires multiple isolation steps to convert a lignocellulose matrix into high-value chemicals. In addition, lignin structural modification, low yields, and poor product characteristics remain challenges. Direct catalytic depolymerization of lignocellulose from date palm biomass was investigated. Production of high value chemicals heavily depends on optimization of different parameters and method of conversion. The goal of the study was to elucidate the role of different parameters on direct conversion of date palm waste in a bench reactor, targeting valuable C5–C12 compounds. The catalytic performance results demonstrated better liquid yields using a commercial alloy catalyst than with laboratory-prepared transition metal phosphide catalysts made using nickel, cobalt, and iron. According to the gas chromatography-mass spectrometry results, C7–C8 compounds were the largest product fraction. The yield improved from 3.6% without a catalyst to 68.0% with a catalyst. The total lignin product yield was lower without a catalyst (16.0%) than with a catalyst (76.0%). There were substantial differences between the carbon distributions from the commercial alloy catalyst, supported transition metal phosphide catalyst, and catalyst-free processes. This may be due to differences between reaction pathways. Lab-made catalysts cracked the biomass to produce more gases than the alloy catalyst. The final pressure rose from 2 bar at the start of the experiment to 146.15 bar and 46.50 bar after the respective reactions. The particle size, solvent type, time, temperature, gas, and catalytic loading conditions were 180 µm, methanol, 6 h, 300 °C, nitrogen, and 5 wt %, respectively. The results from this study provide a deep understanding of the role of different process parameters, the positive attributes of the direct conversion method, and viability of date palm waste as a potential lignocellulose for production of high-value chemicals. Full article

(This article belongs to the Special Issue Catalysis in Lignocellulosic Biomass Conversion)

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12 pages, 1614 KiB

Open AccessFeature PaperArticle

Influence of Biomass Inorganics on the Functionality of H⁺ZSM-5 Catalyst during In-Situ Catalytic Fast Pyrolysis

by Ravishankar Mahadevan, Sushil Adhikari, Rajdeep Shakya and Oladiran Fasina

Catalysts 2021, 11(1), 124; https://doi.org/10.3390/catal11010124 - 15 Jan 2021

Cited by 3 | Viewed by 1920

Abstract

In this study, the contamination of H⁺ZSM-5 catalyst by calcium, potassium and sodium was investigated by deactivating the catalyst with various concentrations of these inorganics, and the subsequent changes in the properties of the catalyst are reported. Specific surface area analysis [...] Read more.

In this study, the contamination of H⁺ZSM-5 catalyst by calcium, potassium and sodium was investigated by deactivating the catalyst with various concentrations of these inorganics, and the subsequent changes in the properties of the catalyst are reported. Specific surface area analysis of the catalysts revealed a progressive reduction with increasing concentrations of the inorganics, which could be attributed to pore blocking and diffusion resistance. Chemisorption studies (NH₃-TPD) showed that the Bronsted acid sites on the catalyst had reacted with potassium and sodium, resulting in a clear loss of active sites, whereas the presence of calcium did not appear to cause extensive chemical deactivation. Pyrolysis experiments revealed the progressive loss in catalytic activity, evident due the shift in selectivity from producing only aromatic hydrocarbons (benzene, toluene, xylene, naphthalenes and others) with the fresh catalyst to oxygenated compounds such as phenols, guaiacols, furans and ketones with increasing contamination by the inorganics. The carbon yield of aromatic hydrocarbons decreased from 22.3% with the fresh catalyst to 1.4% and 2.1% when deactivated by potassium and sodium at 2 wt %, respectively. However, calcium appears to only cause physical deactivation. Full article

(This article belongs to the Special Issue Catalysis in Lignocellulosic Biomass Conversion)

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12 pages, 1824 KiB

Open AccessArticle

Effective Depolymerization of Sodium Lignosulfonate over SO₄²⁻/TiO₂ Catalyst

by Chengguo Mei, Chengjuan Hu, Qixiang Hu, Chang Sun, Liang Li, Xiaoxuan Liang, Yuguo Dong and Xiaoli Gu

Catalysts 2020, 10(9), 995; https://doi.org/10.3390/catal10090995 - 01 Sep 2020

Cited by 4 | Viewed by 1937

Abstract

In this paper, liquefaction of sodium lignosulfonate (SL) over SO₄²⁻/TiO₂ catalyst in methanol/glycerol was investigated. Effects of temperature, time, the ratio of methanol to glycerol and catalyst dosage were also studied. It was indicated that optimal reaction condition (the [...] Read more.

In this paper, liquefaction of sodium lignosulfonate (SL) over SO₄²⁻/TiO₂ catalyst in methanol/glycerol was investigated. Effects of temperature, time, the ratio of methanol to glycerol and catalyst dosage were also studied. It was indicated that optimal reaction condition (the temperature of 160 °C, the time of 1 h, solvent ratio (methanol/glycerol) of 2:1, catalyst dosage of 5 wt % (based on lignin input)) was obtained after sets of experiments. The maximum yields of liquefaction (89.8%) and bio-oil (86.8%) were gained under the optimal reaction conditions. Bio-oil was analyzed by elemental analysis, FT-IR and gas chromatogram and mass spectrometry (GC/MS). It was shown that the functional groups of bio-oil were enriched and calorific value of bio-oil was increased. Finally, it can be seen from GC/MS analysis that the type of products included alcohols, ethers, phenols, ketones, esters and acids. Phenolic compounds mainly consisted of G (guaiacyl)-type phenols. Full article

(This article belongs to the Special Issue Catalysis in Lignocellulosic Biomass Conversion)

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18 pages, 1959 KiB

Open AccessFeature PaperArticle

Acid Hydrolysis of Lignocellulosic Biomass: Sugars and Furfurals Formation

by Katarzyna Świątek, Stephanie Gaag, Andreas Klier, Andrea Kruse, Jörg Sauer and David Steinbach

Catalysts 2020, 10(4), 437; https://doi.org/10.3390/catal10040437 - 17 Apr 2020

Cited by 86 | Viewed by 11745

Abstract

Hydrolysis of lignocellulosic biomass is a crucial step for the production of sugars and biobased platform chemicals. Pretreatment experiments in a semi-continuous plant with diluted sulphuric acid as catalyst were carried out to measure the time-dependent formation of sugars (glucose, xylose, mannose), furfurals, [...] Read more.

Hydrolysis of lignocellulosic biomass is a crucial step for the production of sugars and biobased platform chemicals. Pretreatment experiments in a semi-continuous plant with diluted sulphuric acid as catalyst were carried out to measure the time-dependent formation of sugars (glucose, xylose, mannose), furfurals, and organic acids (acetic, formic, and levulinic acid) at different hydrolysis temperatures (180, 200, 220 °C) of one representative of each basic type of lignocellulose: hardwood, softwood, and grass. The addition of the acid catalyst is followed by a sharp increase in the sugar concentration. Xylose and mannose were mainly formed in the initial stages of the process, while glucose was released slowly. Increasing the reaction temperature had a positive effect on the formation of furfurals and organic acids, especially on hydroxymehtylfurfural (HMF) and levulinic acid, regardless of biomass type. In addition, large amounts of formic acid were released during the hydrolysis of miscanthus grass. Structural changes in the solid residue show a complete hydrolysis of hemicellulose at 180 °C and of cellulose at 200 °C after around 120 min reaction time. The results obtained in this study can be used for the optimisation of the hydrolysis conditions and reactor design to maximise the yields of desired products, which might be sugars or furfurals. Full article

(This article belongs to the Special Issue Catalysis in Lignocellulosic Biomass Conversion)

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13 pages, 3916 KiB

Open AccessArticle

Levulinic Acid Production from Delignified Rice Husk Waste over Manganese Catalysts: Heterogeneous Versus Homogeneous

by Arnia Putri Pratama, Dyah Utami Cahyaning Rahayu and Yuni Krisyuningsih Krisnandi

Catalysts 2020, 10(3), 327; https://doi.org/10.3390/catal10030327 - 14 Mar 2020

Cited by 15 | Viewed by 3641

Abstract

Delignified rice husk waste (25.66% (wt) cellulose) was converted to levulinic acid using three types of manganese catalysts, i.e., the Mn₃O₄/hierarchical ZSM-5 zeolite and Mn₃O₄ heterogenous catalysts, as well as Mn(II) ion homogeneous counterpart. The hierarchical [...] Read more.

Delignified rice husk waste (25.66% (wt) cellulose) was converted to levulinic acid using three types of manganese catalysts, i.e., the Mn₃O₄/hierarchical ZSM-5 zeolite and Mn₃O₄ heterogenous catalysts, as well as Mn(II) ion homogeneous counterpart. The hierarchical ZSM-5 zeolite was prepared using the double template method and modified with Mn₃O₄ through wet-impregnation method. The structure and physicochemical properties of the catalyst materials were determined using several solid-state characterization techniques. The reaction was conducted in a 200 mL-three neck-round bottom flask at 100 °C and 130 °C for a certain reaction time in the presence of 10% (v/v) phosphoric acid and 2% (v/v) H₂O₂ aqueous solution, and the product was analyzed using HPLC. In general, 5-hydroxymethyl furfural (5-HMF) as the intermediate product was produced after 2 h and decreased after 4 h reaction time. To conclude, the Mn₃O₄/hierarchical ZSM-5 heterogenous catalyst gave the highest yield (wt %) of levulinic acid (39.75% and 27.60%, respectively) as the main product, after 8 h reaction time. Full article

(This article belongs to the Special Issue Catalysis in Lignocellulosic Biomass Conversion)

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13 pages, 2107 KiB

Open AccessArticle

Pyrolysis Products Distribution of Enzymatic Hydrolysis Lignin with/without Steam Explosion Treatment by Py-GC/MS

by Yuguo Dong, Xinyu Lu, Chengjuan Hu, Liang Li, Qixiang Hu, Dandan Wang, Chaozhong Xu and Xiaoli Gu

Catalysts 2020, 10(2), 187; https://doi.org/10.3390/catal10020187 - 05 Feb 2020

Cited by 9 | Viewed by 2442

Abstract

This paper investigated the pyrolytic behaviors of enzymatic hydrolysis lignin (EHL) and EHL treated with steam explosion (EHL-SE) by pyrolysis-gas chromatography/mass spectrometer (Py-GC/MS). It was shown that the main component of the pyrolysis products was phenolic compounds, including G-type, H-type, S-type, and C-type [...] Read more.

This paper investigated the pyrolytic behaviors of enzymatic hydrolysis lignin (EHL) and EHL treated with steam explosion (EHL-SE) by pyrolysis-gas chromatography/mass spectrometer (Py-GC/MS). It was shown that the main component of the pyrolysis products was phenolic compounds, including G-type, H-type, S-type, and C-type phenols. With different treatment methods, the proportion of units in phenolic products had changed significantly. Meanwhile, proximate, elemental, and FTIR analysis of both lignin substrates were also carried out for a further understanding of the lignin structure and composition with or without steam explosion treatment. FTIR result showed that, after steam explosion treatment, the fundamental structural framework of the lignin substrate was almost unchangeable, but the content of lignin constituent units, e.g., hydroxyl group and alkyl group, evidently changed. It was noticeable that 2-methoxy-4-vinylphenol with 11% relative content was the most predominant pyrolytic product for lignin after steam explosion treatment. Combined with the above analysis, the structural change and pyrolysis product distribution of EHL with or without steam explosion treatment could be better understood, providing more support for the multi-functional utilization of lignin. Full article

(This article belongs to the Special Issue Catalysis in Lignocellulosic Biomass Conversion)

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27 pages, 6507 KiB

Open AccessArticle

Fermentative Conversion of Two-Step Pre-Treated Lignocellulosic Biomass to Hydrogen

by Karolina Kucharska, Hubert Cieśliński, Piotr Rybarczyk, Edyta Słupek, Rafał Łukajtis, Katarzyna Wychodnik and Marian Kamiński

Catalysts 2019, 9(10), 858; https://doi.org/10.3390/catal9100858 - 15 Oct 2019

Cited by 18 | Viewed by 3324

Abstract

Fermentative hydrogen production via dark fermentation with the application of lignocellulosic biomass requires a multistep pre-treatment procedure, due to the complexed structure of the raw material. Hence, the comparison of the hydrogen productivity potential of different lignocellulosic materials (LCMs) in relation to the [...] Read more.

Fermentative hydrogen production via dark fermentation with the application of lignocellulosic biomass requires a multistep pre-treatment procedure, due to the complexed structure of the raw material. Hence, the comparison of the hydrogen productivity potential of different lignocellulosic materials (LCMs) in relation to the lignocellulosic biomass composition is often considered as an interesting field of research. In this study, several types of biomass, representing woods, cereals and grass were processed by means of mechanical pre-treatment and alkaline and enzymatic hydrolysis. Hydrolysates were used in fermentative hydrogen production via dark fermentation process with Enterobacter aerogenes (model organism). The differences in the hydrogen productivity regarding different materials hydrolysates were analyzed using chemometric methods with respect to a wide dataset collected throughout this study. Hydrogen formation, as expected, was positively correlated with glucose concentration and total reducing sugars amount (Y_TRS) in enzymatic hydrolysates of LCMs, and negatively correlated with concentrations of enzymatic inhibitors i.e., HMF, furfural and total phenolic compounds in alkaline-hydrolysates LCMs, respectively. Interestingly, high hydrogen productivity was positively correlated with lignin content in raw LCMs and smaller mass loss of LCM after pre-treatment step. Besides results of chemometric analysis, the presented data analysis seems to confirm that the structure and chemical composition of lignin and hemicellulose present in the lignocellulosic material is more important to design the process of its bioconversion than the proportion between the cellulose, hemicellulose and lignin content in this material. For analyzed LCMs we found remarkable higher potential of hydrogen production via bioconversion process of woods i.e., beech (24.01 mL H₂/g biomass), energetic poplar (23.41 mL H₂/g biomass) or energetic willow (25.44 mL H₂/g biomass) than for cereals i.e., triticale (17.82 mL H₂/g biomass) and corn (14.37 mL H₂/g biomass) or for meadow grass (7.22 mL H₂/g biomass). Full article

(This article belongs to the Special Issue Catalysis in Lignocellulosic Biomass Conversion)

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22 pages, 1630 KiB

Open AccessArticle

Pyrolysis Kinetics of Hydrochars Produced from Brewer’s Spent Grains

by Maciej P. Olszewski, Pablo J. Arauzo, Przemyslaw A. Maziarka, Frederik Ronsse and Andrea Kruse

Catalysts 2019, 9(7), 625; https://doi.org/10.3390/catal9070625 - 22 Jul 2019

Cited by 27 | Viewed by 4802

Abstract

The current market situation shows that large quantities of the brewer’s spent grains (BSG)—the leftovers from the beer productions—are not fully utilized as cattle feed. The untapped BSG is a promising feedstock for cheap and environmentally friendly production of carbonaceous materials in thermochemical [...] Read more.

The current market situation shows that large quantities of the brewer’s spent grains (BSG)—the leftovers from the beer productions—are not fully utilized as cattle feed. The untapped BSG is a promising feedstock for cheap and environmentally friendly production of carbonaceous materials in thermochemical processes like hydrothermal carbonization (HTC) or pyrolysis. The use of a singular process results in the production of inappropriate material (HTC) or insufficient economic feasibility (pyrolysis), which hinders their application on a larger scale. The coupling of both processes can create synergies and allow the mentioned obstacles to be overcome. To investigate the possibility of coupling both processes, we analyzed the thermal degradation of raw BSG and BSG-derived hydrochars and assessed the solid material yield from the singular as well as the coupled processes. This publication reports the non-isothermal kinetic parameters of pyrolytic degradation of BSG and derived hydrochars produced in three different conditions (temperature-retention time). It also contains a summary of their pyrolytic char yield at four different temperatures. The obtained KAS (Kissinger–Akahira–Sunose) average activation energy was 285, 147, 170, and 188 kJ mol⁻¹ for BSG, HTC-180-4, HTC-220-2, and HTC-220-4, respectively. The pyrochar yield for all hydrochar cases was significantly higher than for BSG, and it increased with the severity of the HTC’s conditions. The results reveal synergies resulting from coupling both processes, both in the yield and the reduction of the thermal load of the conversion process. According to these promising results, the coupling of both conversion processes can be beneficial. Nevertheless, drying and overall energy efficiency, as well as larger scale assessment, still need to be conducted to fully confirm the concept. Full article

(This article belongs to the Special Issue Catalysis in Lignocellulosic Biomass Conversion)

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