Byproduct Of Biodiesel Manufacturing Research Articles

Catalytic Potential-Guided Design of Multi-Enzymatic System for DHA Production from Glycerol

The growing demand for sustainable chemical production has spurred significant interest in biocatalysis. This study is framed within the biocatalytic production of 1,3-dihydroxyacetone (DHA) from glycerol, a byproduct of biodiesel manufacturing. The main goal of this study is to address the challenge of identifying the optimal operating conditions. To achieve this, catalytic potential, a lumped parameter that considers both the activity and stability of immobilized biocatalysts, was used to guide the design of a multi-enzymatic system. The multi-enzymatic system comprises glycerol dehydrogenase (GlyDH) and NADH oxidase (NOX). The enzymatic oxidation of glycerol to DHA catalyzed by GlyDH requires the cofactor NAD+. The integration of NOX into a one-pot reactor allows for the in situ regeneration of NAD+, enhancing the overall efficiency of the process. Furthermore, immobilization on Ni+2 agarose chelated supports, combined with post-immobilization modifications (glutaraldehyde crosslinking for GlyDH), significantly improved the stability and activity of both enzymes. The catalytic potential enabled the identification of the optimal operating conditions, which were 30 °C and pH 7.5, favoring NOX stability. This work establishes a framework for the rational design and optimization of multi-enzymatic systems. It highlights the crucial interplay between individual enzyme properties and process conditions to achieve efficient and sustainable biocatalytic transformations.

Hydrogenolysis of Glycerol by Heterogeneous Catalysis: A Fractional Order Kinetic Model with Analysis

The demand for glycerol, a by-product of biodiesel manufacturing, is anticipated to surpass supply, necessitating efficient conversion techniques for sustainability. The importance of effective conversion techniques is illustrated by the development of a system of fractional order differential equations using a literature reaction model. This study focuses on understanding and describing potential glycerol hydrogenolysis pathways by investigating the kinetics of a catalyzed hydrogenolysis model using qualitative analysis of fractional order differential equations, as there is limited research on the underlying reactions. The model is analyzed qualitatively and quantitatively using fixed point theorems. It is found to be generalized Ulam-Hyers-Rassias stable. The impact of the fractional operator is studied through computational simulations using a two-step Lagrange polynomial. Graphs at different fractional derivative orders show the significant influence of the fractional order on the model's classes. Even though the results are based on a particular kinetic model, they aim to improve comprehension and description of the process.

The synergistic role of Ni-Co bimetallic catalyst for H2-rich syngas production via glycerol dry reforming

A by-product of biodiesel manufacturing, glycerol, is known for its potential to generate syngas via the glycerol dry reforming (GDR) reaction. This study evaluates monometallic and bimetallic Nickel–Cobalt (Ni–Co) (with 15%Co, 3%Ni–12%Co, 4.5%Ni-10.5%Co, 7.5%Ni-7.5%Co, 10.5%Ni-4.5%Co and 15%Ni loading) on Alumina (Al2O3) support extracted from aluminium dross. The catalysts were prepared using an ultrasonic-assisted impregnation process and used in GDR at temperatures ranging from 873 to 1173 K at stoichiometric feed ratio. Analyses result showed that the diluting impact of Ni–Co bimetallic precursors resulted in a reduction of metal crystallite size and improved H2 and CO2 uptake. The conversion of glycerol and product yield were in the order of 3%Ni–12%Co/Al2O3 > 4.5%Ni-10.5%Co/Al2O3 > 7.5%Ni-7.5%Co/Al2O3 > 10.5%Ni-4.5%Co/Al2O3 > 15%Co/Al2O3 > 15%Ni/Al2O3, with 3%Ni–12%Co/Al2O3 having values of 75.6%, 64.7% and 44.8%, for glycerol conversion, H2 and CO yield respectively. All catalysts achieved product ratios ranging from 1.20 to 1.44. The high oxygen vacancies in Ni–Co bimetallic catalysts aided the reduction of carbon formation. Enhanced Ni–Co particles dispersion on Al2O3 support reduced the agglomeration of metal particles, thus, creating smaller crystallite size. The changes in binding energy peaks of Ni and Co were indicative of strong electronic interaction which created Ni–Co bimetallic alloys. 3%Ni–12%Co was regarded as the best catalyst for this study since it was effective in enhancing the conversion of glycerol and product yield.

Preparations and application of dust suppressants from biomass-based materials

ABSTRACT Both natural and anthropogenic fugitive dust can cause serious hazards to the environment and human health. In this study, the development of biodegradable dust suppressants and their environmental impacts were evaluated. Biodegradable dust suppressants were prepared using various biomass-based polymeric materials such as crude glycerol (a by-product of biodiesel manufacturing), biodiesel, palm oil, cooking oil, seaweed mixtures, wakame (Undaria pinnatifida), and red algae. The results of wind-tunnel tests with Korean standard sand demonstrated that spraying diluted mixtures of crude glycerol and biomass materials can significantly reduce the generation of dust. The optimal molar mixing ratio of crude glycerol and the biomass materials was 1:1, and the optimal dilution concentration was determined to be 100 times for the mixture of crude glycerol and biodiesel, palm oil, and cooking oil and 50 times for the mixture of crude glycerol with a seaweed mixture, wakame, and red algae. The suppression ability was 83.4%, 60.4%, 99.5%, and 98.1% for the mixtures of glycerol with soybean oil, palm oil, wakame, and red algae, respectively. The mixtures of glycerol plus wakame or red algae were the most efficient suppressants; they also have substantial biodegradability. Our results suggest that the mixture of crude glycerol with the various oils or the seaweeds may be a promising option to develop nontoxic biodegradable dust suppressants. Implications: Since the early 2010s, anthropogenic fugitive dust from industrial activities has become a serious environmental issue due to its serious hazards to the environment and human health in South Korea. The origin and responsibility of the dusts is still disputable to prepare appropriate actions to take, which could be solved by scientific collaboration with surrounding countries. Regardless, domestic efforts to reduce the generation of fine dust from various sources should also be made. So far, several dust suppressants (mostly salts) were made and used for field application. However, due to their toxic effects, it is necessary to develop a new eco-friendly suppressant that can be biodegraded in the soil and that is not hazardous to human health or the environment. In this study, we try to develop an eco-friendly dust suppressant with low toxicity, to evaluate various potential dust suppressants, and to propose promising candidate products for commercialization and mass production. Ingredients and by-products of biodiesel production, marine biomass, and commercial vegetable oils were selected for the synthesis of suppressants. The optimal mixing ratio was determined, and the suppression ability was evaluated via wind tunnel tests. Considering biodegradability, the most effective suppressants were determined.

Aqueous phase hydrogenolysis of glycerol over Ni/Al-Fe catalysts without external hydrogen addition

The present work studied the aqueous phase hydrogenolysis (APH) of glycerol (a by-product of biodiesel manufacturing) without external hydrogen addition to produce value-added products. A series of catalysts based on 28 molar % of Ni were prepared through co-precipitation by changing the Al/Fe molar ratio. The calcined and used catalysts were characterized by several techniques (ICP-OES, N2-physisorption, XRD, H2-TPR, NH3-TPD, FESEM and STEM). This work examines the effects of the molar ratio of Al/Fe on the physicochemical characteristics of Ni/Al-Fe catalysts and during the APH of glycerol. All the catalysts showed low carbon yields to gases and high carbon yields to liquid products, mainly 1,2-propanediol, acetol and ethylene glycol. Ni/Al3Fe1 catalyst gave the best performance in the APH of glycerol: the highest glycerol conversion (42.31 %), carbon yield to gases (6.57 %) and carbon yield to liquids (30.45%). 1,2-propanediol was the liquid product with the highest carbon selectivity (70.89%).

The effects of rapeseed cake intake during the finishing period on the fatty-acid composition of the longissimus muscle of Limousin steers and changes in meat colour and lipid oxidation during storage

Context Cold-pressed rapeseed cake is a by-product of biodiesel manufacturing that can be obtained on-farm after simple mechanical extraction of the oil. It has a high crude fat content and contains significant amounts of linoleic acid, which make it a promising lipid supplement to modulate meat fatty acid profile. However, previous studies have indicated that using unsaturated fats in beef cattle diets could promote lipid oxidation and reduce meat redness. Aims The present study aimed to evaluate the effects of supplementation of intensively fattened beef steers with cold-pressed rapeseed cake on the fatty acid composition of beef fat and changes in measures of meat colour and lipid oxidation during 6 days of aerobic storage. Methods Sixteen Limousin steers were divided into two homogeneous groups and were fed ad libitum with barley straw and a concentrate mixture supplemented with either PROGRAS (PROGRAS at 2.7% of the diet, high in palmitic acid C16:0 from palm oil; CTR, experimental control; n = 8) or cold-pressed rapeseed cake (CPRC at 14.8% of the diet; CPRC treatment; n = 8) for a period of 9 months. The growth performance and carcass traits were assessed. The intramuscular fatty acids were analysed and the colour stability and lipid oxidation were measured in meat stored aerobically at 4°C for 0, 3 or 6 days. Key results Slaughter bodyweight and average daily gain were not affected by the inclusion of CPRC in the diet. Nor were there any changes in carcass weight, conformation or fatness. The longissimus thoracis from CPRC-fed animals depicted a higher UFA–SFA ratio and a lower atherogenic index than did that from animals fed CTR. Feeding CPRC increased the oleic acid , the vaccenic acid and the rumenic acid proportions in the muscle fat without affecting the ratio of C18:1 trans-10 to C18:1 trans-11. The extents of lipid oxidation and colour deterioration during aging were not affected by the dietary treatments. Conclusions The use of cold-pressed rapeseed cake as a lipid supplement in beef-steer diet improved the fatty acid profile of muscle fat without compromising meat oxidative stability, animal growth performance and carcass characteristics. Implications The supplementation of beef-steer diet with cold-pressed rapeseed cake could be an advantageous economical strategy allowing exploitation of an important by-product of small-scale biodiesel manufacturing to provide consumers with healthier meat.

Adsorption and Decomposition of Glycerol on Pristine and Oxygen Modified Au(111) Surfaces

Research on biomass derived raw materials for conventional catalytic processes, especially those directed to replace human dependence on fossil-based energy, is a high priority academic topic worldwide. Glycerol, the ubiquitous by-product of biodiesel manufacture, is seen as a promising building block due to its versatile functionality. Hence, research efforts to valorize it by selective partial oxidation are widespread. Fundamental knowledge of the interaction of glycerol with metal surfaces in the presence of oxygen is of extreme importance to rationally design new catalytic materials. In this work, a complete study of glycerol interaction with pristine and oxygen modified Au(111) surfaces is presented, by means of X-ray photoelectron and infrared reflection absorption spectroscopies, aided by temperature programmed desorption (TPD) experiments using mass spectrometry. On the clean Au(111) surface, glycerol adsorbs at 150 K through weak interactions between the oxygen atoms from OH groups and gold atoms. No thermal activation is observed and only molecular desorption is detected in TPD at 293 K. On the other hand, when the Au surface is precovered with oxygen atoms in the form of chemisorbed oxygen, glycerol adsorbs in a slightly different geometry and is activated even at low temperatures. The observation of spectral features related to C=O bonds clearly corroborates the activation of the alcohol groups toward partial oxidation intermediates. Possible products desorbing from the surface due to this activation are identified as dihydroxyacetone, hydroxypiruvic, tartronic and formic acid, as well as H2O and CO2.

Perspective on catalyst development for glycerol reduction to C3 chemicals with molecular hydrogen

Recent developments in catalytic reduction with H2 of glycerol, which is a by-product of biodiesel manufacture, and the involved chemistry are summarized and reviewed. There are more than ten potential C3 products of glycerol reduction. Among them, 1,2-propanediol can be obtained in very high yield and the production from glycerol is now commercialized. Production of 1,3-propanediol, allyl alcohol and propylene are now possible in > 60%, > 90% and > 80% yield, respectively. Key reaction steps are metal-catalyzed dehydrogenation/hydrogenation, acid-catalyzed dehydration, carbonyl-induced dehydration, metal-catalyzed direct hydrogenolysis and deoxydehydration. The 2-Propanol and small-ring compounds (oxetane, propylene oxide) cannot be produced from glycerol by combinations of these key reaction steps, and no catalytic system is known at present, although the conversion reactions have minus ∆G°.

Photocatalytic hydrogen production from glycerol solution at room temperature by ZnO-ZnS/graphene photocatalysts

Glycerol is a byproduct of biodiesel manufacturing. The room temperature photocatalytic hydrogen generation from glycerol by the ZnO-ZnS/graphene photocatalyst was investigated. The in-situ C K-edge near edge X-ray absorption fine structure (NEXAFS) spectra were measured with/without light illumination to study the electronic properties of photocatalysts at atomic and molecular level. A mechanism of water splitting and glycerol oxidation/reforming reactions over the photocatalyst under light irradiation is proposed. Effects of graphene content in photocatalysts and glycerol concentration in solution on the photocatalytic activity were examined. The results of enhanced photocurrents, fluorescence quenching, NEXAFS spectra, and decreased arc radius of electrochemical impedance spectra of ZnO-ZnS/graphene photocatalysts revealed the fast transfer of photoexcited electrons from ZnO-ZnS nanoparticles to graphene. There was an optimal graphene content and a glycerol concentration for the maximum photocatalytic H2 production rate (1070 μmol h−1 g−1). Incorporation of graphene can enhance the separation of photogenerated charge through the ZnO-ZnS/graphene interfaces and improve the photocatalytic H2 production rate of the photocatalysts. The composite photocatalysts exhibited improved performance because of efficient charge separation and enhanced light absorption.

Sorption-enhanced steam reforming of glycerol over Ni[sbnd]Cu[sbnd]Ca[sbnd]Al catalysts for producing fuel-cell grade hydrogen

The concentration of CO in the high-purity hydrogen from sorption-enhanced steam reforming (SESR) processes is usually too high to be directly used in fuel cells. Herein, we report a production of fuel-cell grade H2 with <30 ppm CO through SESR of glycerol (SESRG), a by-product of biodiesel manufacture. High purity H2 can be produced by employing a catalyst-sorbent hybrid material composed of Ni as catalyst, CaO as CO2 sorbent and Ca12Al14O33 as spacer. By introducing copper as promoter, the performance of the bi-functional catalyst could be modified to produce a 97.15 vol% purity of H2 with 28 ppm CO. With an optimized Ni/Cu ratio, the 7.5Ni–7.5Cu catalyst shows the excellent stability for producing about 97% H2 with <30 ppm CO for ten cycles. The characterizations and model reaction tests indicate that copper can affect CO, CO2 hydrogenation and water gas shift reaction to adjust the performance of SESRG reaction. The results presented here show the promise of tuning the catalyst composition for achieving high quality H2 through SESR processes.

A bi-functional Co–CaO–Ca12Al14O33 catalyst for sorption-enhanced steam reforming of glycerol to high-purity hydrogen

Sorption enhanced steam reforming of glycerol (SESRG) enables the production of high-purity hydrogen from the by-product of biodiesel manufacture. To this end, highly stable catalysts and CO2 sorbents are desired to overcome the performance degradation at high temperatures. Herein, a bi-functional catalyst, Co–CaO–Ca12Al14O33, is proposed to couple CO2 sorption and catalytic reforming of glycerol on nanoscale. The catalyst was derived from a Co–Ca–Al hydrotalcite-like (HTl) material to achieve homogeneous mixing of Co, CaO and Ca12Al14O33 as a spacer to prevent CaO sintering. At Ca/Al of 2.8, the highest catalytic activity and sorption capability were reached. Over the optimized catalyst, high-purity H2 of 96.4% was produced at 525°C through SESRG during the pre-breakthrough stage. High stability of the bi-functional catalyst was demonstrated by a cyclic SESRG-calcination operation up to 50 times. The role of Ca12Al14O33 as spacer of CaO was proved by XRD and TEM-EDS analysis. In addition, it was found that Ca3Co2O6, which is formed during the calcination stage and is reduced during the SESRG to release Co catalysts, may act as a dynamic reservoir of Co catalysts to prevent Co from sintering, leading to an excellent SESRG activity and stability.

EBPR using crude glycerol: assessing process resiliency and exploring metabolic anomalies.

Enhanced biological phosphorus removal (EBPR) is predicated on exposing bacteria to cyclical anaerobic/aerobic environments while providing volatile fatty acids (VFAs). Combined, this environment enriches for phosphorus accumulating organisms (PAOs) and induces metabolisms to ensure excess phosphorus removal. Crude glycerol (CG), a byproduct of biodiesel manufacturing, is an alternate waste stream that could be substituted to achieve excess phosphorus removal; research into the use of CG yielded unexpected findings. While CG was an excellent substrate to accomplish and/or help achieve excess phosphorus removal, CG-fed bacteria did not consistently exhibit theoretical EBPR metabolisms. Specifically, anaerobic phosphorus release was not required for successful EBPR; however, carbon cycling patterns were consistent with theory. Analysis of results suggests that PAOs will first leverage carbon to generate energy anaerobically; only as needed will the bacteria utilize polyphosphate reserves anaerobically. Results also demonstrated that excess phosphorus removal can be achieved with a small fraction of PAOs.

Comparison of Photocatalytic Hydrogen Production from Glycerol and Crude Glycerol Obtained from Biodiesel Processing

Photocatalytic hydrogen generation from aqueous solutions of glycerol and crude glycerol (byproduct of biodiesel manufacturing) were compared using Pt/TiO2 and CuOx/TiO2 catalysts. Glycerol solutions generated more H2 than crude glycerol solutions, with the H2 generation rate approximately 2.5 times higher for Pt/TiO2 and approximately 4 times higher for CuOx/TiO2. Pt/TiO2 produced more H2 than CuOx/TiO2, with a ratio nearly 2.5 times higher for glycerol and nearly 3.5 times higher for crude glycerol. Ion exchange of crude glycerol solutions to replace Na+ with Li+ or K+ had little impact on reactions with CuOx/TiO2 whereas ion exchange with Li+ moderately reduced reaction rates with Pt/TiO2. An anti-foam agent reduced foaming problems associated with higher concentrations of crude glycerol but itself degraded. The addition of 0.4 mM NaH2PO4 reduced the H2 generation rate by nearly 60 % whereas the presence of 0.4 mM NaCl, 0.4 mM NaNO3 or 0.2 mM Na2SO4 reduced the H2 generation rate by only 10–20 % over the course of the reaction.

Glycerol dehydroxylation in hydrogen on a Raney cobalt catalyst

Glycerol dehydroxylation on a Raney cobalt catalyst in hydrogen was studied. It was found that with an increase in temperature from 140 to 200°C at a hydrogen pressure of 30 MPa, glycerol conversion increases from 14 to 97%. The glycerol is completely converted in 20 h, and the yield of 1,2-propanediol is 40%. With an increase in H2 pressure from 3 to 8 MPa, the glycerol conversion increases from 34 to 95%, and the yield of 1,2-propanediol increases from 18 to 38%. The maximum yield of 1,2-propanediol is 44% at 200°C and a hydrogen pressure of 3 MPa. The glycerol dehydroxylation in hydrogen on heterogeneous catalysts can be considered a promising method of glycerol conversion when glycerol is a byproduct of biodiesel manufacture from vegetable oil and animal fats.

Greening the Construction Industry: Enhancing the Performance of Cements by Adding Bioglycerol

The addition of glycerol, a by-product of biodiesel manufacturing, to cement eases its grinding and handling while considerably enhancing the strength of the resulting concrete. The benefits of using bioglycerol are significant both for the environment and for the concrete and biodiesel industries. The advantages for industry derive from having a single, readily available material that offers all three major technical improvements required of cement additives, namely enhanced concrete strength, and grinding and handling aids for cement, while the environmental impact is eased by using bioglycerol instead of ethylene glycol and hydroxyamines that are presently used as major components of cement additives.

Cover Picture: Highly Active Catalysts for the Telomerization of Crude Glycerol with 1,3‐Butadiene (ChemSusChem 3/2008)

The cover picture shows a palladium-based molecular catalyst for the direct telomerization of glycerol with 1,3-butadiene, which presents a promising technology allowing direct access to C8-chain mono-, di-, and triethers of glycerol as useful chemical building blocks. Crude glycerol is obtained as a by-product of biodiesel manufacturing, for example, from rapeseed or sunflowers. In their Communication on page 193 ff., B. M. Weckhuysen et al. report how palladium complexes with methoxy-substituted triphenylphosphine ligands entail superior catalytic activity in the telomerization of not only pure glycerol but also crude glycerol. The resulting C8-chain ethers can potentially be applied in the production of surfactant or detergent molecules, as illustrated by the structures set against the foam-like background.