Biodiesel production from waste cooking oil over sulfonated catalysts

Biodiesel production from waste cooking oil with methanol was carried out in the presence of poly(vinyl alcohol) with sulfonic acid groups (PVA-SO₃H) and polystyrene with sulfonic acid groups (PS-SO₃H), at 60°C. The PVA-SO₃H catalyst showed higher catalytic activity than the PS-SO₃H one. In order to optimize the reaction conditions, different parameters were studied. An increase of waste cooking oil conversion into fatty acid methyl esters with the amount of PVA-SO₃H was observed. When the transesterification and esterification of WCO was carried out with ethanol over PVA-SO₃H, at 60°C, a decrease of biodiesel production was also observed. The WCO conversion into fatty acid ethyl ester increased when the temperature was increased from 60 to 80°C. When different amounts of free fatty acids were added to the reaction mixture, a slight increase on the conversion was observed. The PVA-SO₃H catalyst was reused and recycled with negligible loss in the activity.     

Biodiesel production from waste sunflower oil by using Amberlyst 46 as a catalyst

In this study, simultaneous transesterification and esterification of high acid value sunflower oil to fatty acid methyl esters was studied using Amberlyst 46 as a heterogeneous catalyst. The influence of reaction conditions such as molar ratio of methanol/oil, reaction time, and reaction temperature was investigated. The highest fatty acids methyl esters yield of 75.8% was obtained in presence of 6 wt% oleic acid content under reaction conditions of 20 wt% Amberlyst 46 catalyst amount, 6/1 methanol/oil molar ratio, reaction temperature of 130°C, and reaction time of 10 h.     

Biodiesel production from two stage esterification of simarouba glauca seed oil and its characterization

In this work, biodiesel was produced from simarouba glauca seed oil through a two-stage acid-alkali esterification process. Concentrated sulphuric acid and sodium hydroxide were used as catalysts for acid and alkaline catalyzed esterification process, respectively. The free fatty acid content of the oil was reduced from 3.5 to 0.2%. The major properties of oil and its biodiesel were studied. Upon two-stage esterification, kinematic viscosity was reduced from 45.75 to 3.1 cSt and the acid value was reduced from 6.9348 to 0.4 mg KOH/g. The measured physio-chemical properties are within the limits set by ASTM biodiesel standards.     

Biodiesel production by esterification of palm fatty acid distillate

Production of fatty acid methyl ester (FAME) from palm fatty acid distillate (PFAD) having high free fatty acids (FFA) was investigated in this work. Batch esterifications of PFAD were carried out to study the influence of: including reaction temperatures of 70–100 °C, molar ratios of methanol to PFAD of 0.4:1–12:1, quantity of catalysts of 0–5.502% (wt of sulfuric acid/wt of PFAD) and reaction times of 15–240 min. The optimum condition for the continuous esterification process (CSTR) was molar ratio of methanol to PFAD at 8:1 with 1.834 wt% of H₂SO₄ at 70 °C under its own pressure with a retention time of 60 min. The amount of FFA was reduced from 93 wt% to less than 2 wt% at the end of the esterification process. The FAME was purified by neutralization with 3 M sodium hydroxide in water solution at a reaction temperature of 80 °C for 15 min followed by transesterification process with 0.396 M sodium hydroxide in methanol solution at a reaction temperature of 65 °C for 15 min. The final FAME product met with the Thai biodiesel quality standard, and ASTM D6751-02.     

Biodiesel production by esterification of oleic acid over zeolite Y prepared from kaolin

Zeolite Y, with a Si/Al ratio 3.1, was prepared using Iraqi kaolin and tested as a catalyst in the liquid-phase esterification of oleic acid (a simulated free fatty acid frequently used as a model reaction for biodiesel production). XRD confirmed the presence of the characteristic faujasite structure of zeolite Y, and further analysis was conducted using BET adsorption, FTIR spectroscopy, XRF, DLS particle size and SEM. A range of experimental conditions were employed to study the reaction; alcohol/oleic acid molar ratio, temperature, and catalyst mass loading. The optimum conditions for the reaction were observed at 70 °C, 5 wt% catalyst loading and 6:1 ethanol to oleic acid molar ratio. The oleic acid conversion using the zeolite prepared from kaolin was 85% after 60 min, while the corresponding value for a commercial sample of HY zeolite was 76%. Our findings show that low Si/Al ratio zeolite Y is a suitable catalyst for esterification, which is in contrast to the widespread view of the unsuitability of zeolites, in general, for such applications.     

Biodiesel production from degummed Jatropha curcas oil using constant-temperature ultrasonic water bath

This paper studied tri-basic potassium phosphate for transesterification process with degummed crude Jatropha curcas oil using constant-temperature, ultrasonic water bath generating low-intensity pulses with good energy distribution converting the maximum amount of biodiesel. Tri-basic potassium phosphate is suitable for J. curcas oil when the free fatty acid (FFA) content is less than 2%. The optimal reaction levels are catalyst 1.0 wt%, temperature of 50°C, and methanol-to-oil molar ratio of 12:1. The yield is 98% after 45 min, at 20 kHz frequency. The catalytic activity is found similar to potassium hydroxide and the catalyst solubility is only 4.27 ppm.     

Biodiesel production by esterification of oleic acid with short-chain alcohols under ultrasonic irradiation condition

Production of fatty acid ethyl ester (FAEE) from oleic acid (FFA) with short-chain alcohols (ethanol, propanol, and butanol) under ultrasonic irradiation was investigated in this work. Batch esterification of oleic acid was carried out to study the effect of: test temperatures of 10–60 °C, molar ratios of alcohol to oleic acid of 1:1–10:1, quantity of catalysts of 0.5–10% (wt of sulfuric acid/wt of oleic acid) and irradiation times of 10 h. The optimum condition for the esterification process was molar ratio of alcohol to oleic acid at 3:1 with 5 wt% of H₂SO₄ at 60 °C with an irradiation time of 2 h.     

Biodiesel production from castor oil in Brazil: A difficult reality

The Brazilian National Program for Production and Use of Biodiesel (PNPB in Portuguese) has created a huge demand for biodiesel in Brazil. The PNPB is strongly based on social development through the inclusion of family farmers in projects integrated with biodiesel power plants. Among the various oilseeds, castor bean (Ricinus communis L.) was identified as the ideal one to promote social development in the semi-arid region. However, although promising, the mechanisms of the federal program are still insufficient to promote the effective participation of family farmers. This research shows that companies are facing huge problems in implementing contracts with family farmers. It describes and analyzes the functioning dynamics of this agro-production chain. This paper addresses the identification and the discussion of these obstacles, in order to increase the competitiveness of the biodiesel agribusiness chain, based on castor oil social projects in Brazil.     

Optimization of biodiesel production from waste fish oil

The present study deals with the production of biodiesel using waste fish oil. The research assesses the effect of the transesterification parameters on the biodiesel yield and its properties, including temperature (40–60 °C), molar ratio methanol to oil (3:1–9:1) and reaction time (30–90 min). The experimental results were fitted to complete quadratic models and optimized by response surface methodology. All the biodiesel samples presented a FAME content higher than 93 wt.% with a maximum, 95.39 wt.%, at 60 °C, 9:1 of methanol to oil ratio and 90 min. On the other hand, a maximum biodiesel yield was found at the same methanol to oil ratio and reaction time conditions but at lower temperature, 40 °C, which reduced the saponification of triglycerides by the alkaline catalyst employed. Adequate values of kinematic viscosity (measured at 30 °C) were obtained, with a minimum of 6.30 mm²/s obtained at 60 °C, 5.15:1 of methanol to oil ratio and 55.52 min. However, the oxidative stability of the biodiesels produced must be further improved by adding antioxidants because low values of IP, below 2.22 h, were obtained. Finally, satisfactory values of completion of melt onset temperature, ranging from 3.31 °C to 3.83 °C, were measured.     

Acid-catalyzed production of biodiesel from waste frying oil

The reaction kinetics of acid-catalyzed transesterification of waste frying oil in excess methanol to form fatty acid methyl esters (FAME), for possible use as biodiesel, was studied. Rate of mixing, feed composition (molar ratio oil:methanol:acid) and temperature were independent variables. There was no significant difference in the yield of FAME when the rate of mixing was in the turbulent range 100 to 600 rpm. The oil:methanol:acid molar ratios and the temperature were the most significant factors affecting the yield of FAME. At 70 °C with oil:methanol:acid molar ratios of 1:245:3.8, and at 80 °C with oil:methanol:acid molar ratios in the range 1:74:1.9–1:245:3.8, the transesterification was essentially a pseudo-first-order reaction as a result of the large excess of methanol which drove the reaction to completion (99±1% at 4 h). In the presence of the large excess of methanol, free fatty acids present in the waste oil were very rapidly converted to methyl esters in the first few minutes under the above conditions. Little or no monoglycerides were detected during the course of the reaction, and diglycerides present in the initial waste oil were rapidly converted to FAME.     

Optimization of biodiesel production from waste cooking oil

The sequences of development that cut across industrialization, population growth, environmental and economic reasons led individuals and organizations to have direct responsibilities in the development and implementation of sound technologies that will curtail the emissions of hazardous gases and particulate matter. As a result, this study focuses on the optimization and characterization of biodiesel from waste cooking oil. It involves the characterization of the feed stock, the transesterification, the purification of the transesterified waste cooking oil, the optimization of the biodiesel produced using 2⁴ factorial experimental designs, and the characterization of the biodiesel produced from waste cooking oil. Result obtained reveals that operating temperature of 30°C, transesterification time of 60 min, catalyst weight of 0.5%, and alcohol to oil ratio of 6:1 are the optimum conditions with optimum yield of 90% of biodiesel from waste cooking oil. Experimental determinations of some useful properties of the biodiesel produced were carried out for the purpose of confirming the quality as well as the identification of the biofuel. These were moisture content, specific gravity, viscosity, acid value, sulfated ash, cetane number, cloud point, flash point, distillation characteristic, and refractive index. The results obtained were 0.097%, 0.854, 4.90 mm²/s, 0.80 mgKOH/g, 0.01%, 48.00, 53°F, 143°C, 320°C, and 1.412, respectively. The results obtained showed that all the parameters compare favorably with literatures and the standard biodiesel specifications; hence production of biodiesel from waste cooking oil is possible.     

Biodiesel production from waste cooking oil using heterogeneous catalysts and its operational characteristics on variable compression ratio CI engine

In the present work, the optimum biodiesel conversion from waste cooking oil to biodiesel through transesterification method was investigated. The base catalyzed transesterification under different reactant proportions such as the molar ratio of alcohol to oil and mass ratio of catalyst to oil was studied for optimum production of biodiesel. The optimum condition for base catalyzed transesterification of waste cooking oil was determined to be 12:1 and 5 wt% of zinc doped calcium oxide. The fuel properties of the produced biodiesel such as the calorific value, flash point and density were examined and compared to conventional diesel. The properties of produced biodiesel and their blend for different ratios (B20, B40, B60, B80 and B100) were comparable with properties of diesel oil and ASTM biodiesel standards. Tests have been conducted on CI engine which runs at a constant speed of 1500 rpm, injection pressure of 200 bar, compression ratio 15:1 and 17.5, and varying engine load. The performance parameters include brake thermal efficiency, brake specific energy consumption and emissions parameters such as Carbon monoxide (CO), Hydrocarbon (HC), Oxides of Nitrogen (NOx) and smoke opacity varying with engine load (BP). Diesel engine's thermal performance and emission parameters such as CO, HC, and NOx on different biodiesel blends demonstrate that biodiesel produced from waste cooking oil using heterogeneous catalyst was suitable to be used as diesel oil blends and had lesser emissions as compared to conventional diesel.     

生物炭吸附去除水中有机污染物的研究进展

生物炭由于具有发达的孔隙结构以及表面富含多种官能团,对各种污染物均具有良好的吸附性能,因此被广泛应用于土壤污染修复和水体净化等领域,其中采用生物炭吸附去除水体中有机污染物成为近年来的研究热点之一。主要从生物炭材料的制备及吸附水中有机污染物的应用、吸附机制、影响因素等几个方面进行了综述,并对生物炭吸附的未来研究方向进行了初步探讨。     

Photofermentive production of biohydrogen from oil palm waste hydrolysate

Oil palm empty fruit bunch (OPEFB) was hydrolyzed with dilute sulfuric acid (6% v/v; 8 mL acid per g dry OPEFB) at 120 °C for 15-min to release the fermentable sugars. The hydrolysate contained xylose (23.51 g/L), acetic acid (2.44 g/L) and glucose (1.80 g/L) as the major carbon components. This hydrolysate was used as the sole carbon source for photofermentive production of hydrogen using a newly identified photosynthetic bacterium Rhodobacter sphaeroides S10. A Plackett–Burman experimental design was used to examine the influence of the following on hydrogen production: yeast extract concentration, molybdenum concentration, magnesium concentration, EDTA concentration and iron concentration. These factors influenced hydrogen production in the following decreasing order: yeast extract concentration > molybdenum concentration > magnesium concentration > EDTA concentration > iron concentration. Under the conditions used (35 °C, 14.6 W/m² illumination, initial pH of 7.0), the optimal composition of the culture medium was (per L): mixed carbon in OPEFB hydrolysate 3.87 g, K₂HPO₄ 0.9 g, KH₂PO₄ 0.6 g, CaCl₂⋅2H₂O 75 mg, l-glutamic acid 795.6 mg, FeSO₄⋅7H₂O 11 mg, Na₂MoO₂⋅2H₂O 1.45 mg, MgSO₄⋅7H₂O 2.46 g, EDTA 0.02 g, yeast extract 0.3 g). With this medium, the lag period of hydrogen production was 7.65 h, the volumetric production rate was 22.4 mL H₂/L medium per hour and the specific hydrogen production rate was 7.0 mL H₂/g (xylose + glucose + acetic acid) per hour during a 90 h batch culture of the bacterium. Under optimal conditions the conversion efficiency of the mixed carbon substrate to hydrogen was nearly 29%.     

Supercritical water gasification of fuel gas production from waste lignin: The effect mechanism of different oxidized iron-based catalysts

Iron and iron oxides have been employed to catalyze supercritical water gasification (SCWG) of lignin, a typical component of pulp and paper mill wastewater. To investigate the effects of different oxidation sates of Fe-based catalysts during SCWG process, all simulations were carried out through ReaxFF molecular dynamics method. During the catalytic SCWG process, the degradation rate of guaiacyl dimer lignin (GDL) molecule was inversely proportional to the valence state of iron, the higher oxidation state of Fe in iron-based catalyst was, the lower the catalytic degradation ability would be, and then GDL molecule underwent a series of reactions, accompanying with the generation of small molecules, among most of them were fuel gas products. In terms of gas products, Fe catalyst had a unique advantage in catalytic hydrogen production. Moreover, it is found that iron with low oxidation state was beneficial to the formation of CO, while iron with high oxidation state was CO₂. Our simulation results further revealed the formation mechanisms of CO, CO₂ and CH₄. Migration of lattice oxygen in iron oxides was also visualized through figure, and spent catalyst showed different sources in the final, demonstrating that SCW participates in the entire reaction providing not only H but also O free radicals.     

Enzymatical hydrolysis of food waste and ethanol production from the hydrolysate

The aim of present paper was to investigate the prospect for the use of food waste, an important municipal waste, as a potential substrate to generate hydrolysates for fuel ethanol production. The critical variables that affected reducing sugar production from food waste were identified by Plackett–Burman design (glucoamylase loud, time, temperature and pH) and further optimized by using a four factor central composite design of response surface methodology. According to the results of response surface analysis, the optimum conditions for reducing sugar production were determined to be glucoamylase loud of 142.2 u/g, saccharification pH of 4.82, enzyme reaction temperature of 55 °C, enzyme reaction time of 2.48 h. Reducing sugar production (164.8 g/L) in the optimized condition was in good agreement with the value predicted by the quadratic model (164.3 g/L), thereby confirming its validity. Furthermore, the obtained liquid phase of food waste hydrolysate was utilized for production of ethanol by using Saccharomyces cerevisiae H058 fermentation. In order to develop an economical process for transforming food waste hydrolysates to ethanol, non-sterilized and sterilized processes were compared in the experiments. The result shows non-sterilized fermentation without undergoing heat treatment was better due to the unspoiled nutrients inside. These results helped to find the effective strategies to utilize food waste for ethanol production.     

Evaluation of Zymomonas-based ethanol production from a hydrolysed waste starch stream

Residual starch from flour wet milling, supplemented with crushed wheat grains, was hydrolysed and evaluated for ethanol production by Zymomonas mobilis ZM4 and an industrial ethanol-producing strain of Saccharomyces cerevisiae. The feasibility of replacing yeast extract with ammonium sulphate or corn steep liquor as a nitrogen source in the hydrolysed waste starch (HWS) media was confirmed. With glucose concentrations of 80–110 g L⁻¹, Z. mobilis ZM4 demonstrated superior fermentation kinetics in all three media, with higher specific rates of glucose uptake and ethanol production, greater productivities and ethanol yields close to theoretical. In a repeated batch process (five cycles), rapid cell concentration was achieved between cycles (via cell settling) with the flocculent strain Z. mobilis ZM401. This resulted in very significant productivity increases and illustrated the potential use of this strain for improved technology and cost reductions in larger scale processes.     

Biodiesel production from castor oil using potassium hydroxide as a catalyst: Simulation and validation

The key objective of the present research is to optimize and investigate the biodiesel production from ricinuscommunis (castor) oil using microwave-assisted hybrid transesterfication process under various conditions such as microwave power, treatment time, ethanol:oil ratio and catalyst concentration (KOH). Response surface methodology (RSM) coupled with four factors with a three-level Box–Behnken response surface design (BBD) was employed to model the transesterfication technique. The obtained results were analyzed by analysis of variance (ANOVA) and a second-order polynomial model was developed to study the interactive effect of process factors on biodiesel production. Derringer’s desired function methodology was used for the optimization and optimum conditions for maximizing the biodiesel production. Under optimum conditions, the predicted biodiesel production was found to be 95% with a desirability value of 0.998. The fuel properties of the produced biodiesel were compared with the ASTM D6751 standards.     

Biodiesel production from jatropha oil (Jatropha curcas) with high free fatty acids: An optimized process

Response surface methodology (RSM) based on central composite rotatable design (CCRD) was used to optimize the three important reaction variables—methanol quantity (M), acid concentration (C) and reaction time (T) for reduction of free fatty acid (FFA) content of the oil to around 1% as compared to methanol quantity (M′) and reaction time (T′) and for carrying out transesterification of the pretreated oil. Using RSM, quadratic polynomial equations were obtained for predicting acid value and transesterification. Verification experiments confirmed the validity of both the predicted models. The optimum combination for reducing the FFA of Jatropha curcas oil from 14% to less than 1% was found to be 1.43% v/v H₂SO₄ acid catalyst, 0.28 v/v methanol-to-oil ratio and 88-min reaction time at a reaction temperature of 60 °C as compared to 0.16 v/v methanol-to-pretreated oil ratio and 24 min of reaction time at a reaction temperature of 60 °C for producing biodiesel. This process gave an average yield of biodiesel more than 99%. The fuel properties of jatropha biodiesel so obtained were found to be comparable to those of diesel and confirming to the American and European standards.