This study evaluated the utilisation of biomass wastes as catalyst supports by comparing the catalytic performance of papaya seed, empty fruit bunch (EFB) and corncob biomass waste derived carbon ...based acid catalysts applied for biodiesel production through esterification reaction of palm fatty acid distillate (PFAD) and methanol. Arylation of 4-benzenediazonium sulfonate synthesis method was able to sulfonate the catalyst support efficiently. The activated carbon (AC) synthesised possessed high porosity with surface area ranged between 639.68 and 972.66 m2/g. The effect of catalyst synthesising condition including carbonisation temperature (600–1000 °C), sulfonation time (0.5–2.5 h) and sulfanilic acid to AC weight ratio (3:1–13:1) towards the FAME yield and free fatty acid (FFA) conversion were evaluated. At the optimum catalyst synthesis conditions, corncob waste derived sulfonated AC catalyst exhibited the highest FAME yield and FFA conversion of 72.09% and 93.49%, respectively. Reusability study showed that corncob waste derived sulfonated AC catalyst was able to achieve relatively high FAME yield at the first two reaction cycles. The esterification reaction followed the irreversible pseudo-homogeneous reaction model. The high catalytic efficiency of the catalyst had shown its high potential to fit into the cost-effective and sustainable framework for biodiesel production.
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•Utilisation of various biomass waste as catalyst support for biodiesel production.•4-BDS sulfonation method was efficient for esterification reaction.•Sulfonated catalyst derived from corncob exhibited high catalytic performance.•Biodiesel yield and FFA conversion were obtained at 72.09% and 93.49%, respectively.•The reaction obeyed irreversible pseudo-homogeneous reaction model.
Interest in biodiesel research has escalated over the years due to dwindling fossil fuel reserves. The implementation of a carbon-based solid acid catalyst in biodiesel production eradicates the ...separation problems associated with homogeneous catalysis. However, its application in the glycerol-free interesterification process for biodiesel production is still rarely being studied in the literature. In this study, novel environmentally benign catalysts were prepared from oil palm empty fruit bunch (OPEFB) derived activated carbon (AC) which is sustainable and low cost via direct sulfonation using concentrated sulfuric acid. The effects of synthesizing variables such as carbonization and sulfonation temperatures with different holding times towards the fatty acid methyl ester (FAME) yield in interesterification reaction with oleic acid and methyl acetate were investigated in detail. It was found that the optimum carbonization temperature and duration together with sulfonation temperature and duration were 600 °C, 3 h, 100 °C and 6 h, respectively. The catalyst possessed an amorphous structure with a high total acid density of 9.0 mmol NaOH g−1 due to the well-developed porous framework structure of the carbon support. Under these optimum conditions, the OPEFB derived solid acid catalyst recorded an excellent catalytic activity of 50.5% methyl oleate yield at 100 °C after 8 h with 50:1 methyl acetate to oleic acid molar ratio and 10 wt% catalyst dosage. The heterogeneous acid catalyst derived from OPEFB had shown promising properties that made them highly suitable for cost-effective and environmental-friendly glycerol-free biodiesel production.
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•First application of OPEFB-derived solid catalyst for interesterification reaction•Carbonization temperature affects the structural properties of the catalyst support.•Sulfonation temperature influences the loading efficiency of catalytic active sites.•Synthesized catalyst possesses amorphous structure with large microporous framework.•A FAME yield of 50.5% was obtained at optimum catalyst synthesizing conditions.
This review appraises the latest scientific progress and the accomplishments of interesterification technology as an alternative to conventional transesterification reaction. The merits and ...limitations of various types of catalytic techniques as well as non-catalytic supercritical glycerol-free processes have been elucidated with a comprehensive comparison. Contrary to the cheap price of glycerol, the higher-revenue by-products, triacetin and glycerol carbonate, will boost the gross profit margin of biodiesel production. The influences of reaction parameters such as reactant ratio, catalyst loading, reaction time, temperature, and co-solvent addition are also addressed. According to the latest research, the alkali-catalyzed and non-catalytic supercritical interesterifications are preferable due to higher yield. Methyl acetate, ethyl acetate and dimethyl carbonate do not inhibit lipase activity, unlike typical alcohols. Acidic catalysis may be the way forward to resolve the extreme operating conditions of non-catalytic supercritical interesterification, high cost of enzymes and manage waste feedstocks with high free fatty acid and water contents under moderate conditions. Currently, the majority of interesterification reactions were undertaken on laboratory size, whereas just a handful was evaluated on a pilot scale. A continuous research in interesterification technology is necessary by conducting a thorough investigation of the feasibility of state-of-the-art technology to engage a wide array of feedstocks. Future study should also concentrate on microbes and agricultural waste as a sustainable route for energy recovery from renewable feedstocks.
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•Alkyl acetates and dimethyl carbonate posed as viable alternatives to alcohols.•Value-added by-products were produced instead of surplus glycerol.•Recent methodologies for interesterification reaction were comprehensively reviewed.•Pros and cons of different glycerol-free biodiesel production pathways were elucidated.•Effects of distinct reaction parameters on biodiesel yield were investigated.
In recent years, environmental problems caused by the use of fossil fuels and the depletion of petroleum reserves have driven the world to adopt biodiesel as an alternative energy source to replace ...conventional petroleum-derived fuels because of biodiesel's clean and renewable nature. Biodiesel is conventionally produced in homogeneous, heterogeneous, and enzymatic catalysed processes, as well as by supercritical technology. All of these processes have their own limitations, such as wastewater generation and high energy consumption. In this context, the membrane reactor appears to be the perfect candidate to produce biodiesel because of its ability to overcome the limitations encountered by conventional production methods. Thus, the aim of this paper is to review the production of biodiesel with a membrane reactor by examining the fundamental concepts of the membrane reactor, its operating principles and the combination of membrane and catalyst in the catalytic membrane. In addition, the potential of functionalised carbon nanotubes to serve as catalysts while being incorporated into the membrane for transesterification is discussed. Furthermore, this paper will also discuss the effects of process parameters for transesterification in a membrane reactor and the advantages offered by membrane reactors for biodiesel production. This discussion is followed by some limitations faced in membrane technology. Nevertheless, based on the findings presented in this review, it is clear that the membrane reactor has the potential to be a breakthrough technology for the biodiesel industry.
The conversion of carbon-rich biomass into valuable material is an environmental-friendly approach for its reutilization. In this study, coconut shell–derived biochar, graphitic carbon nitride (g-C
3
...N
4
), g-C
3
N
4
/biochar, titanium dioxide (TiO
2
)/biochar, zinc oxide (ZnO)/biochar, and ferric oxide (Fe
2
O
3
)/biochar were synthesized and characterized by using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), surface area analysis, UV-Vis diffuse reflectance spectroscopy (DRS), and zeta potential analysis. The g-C
3
N
4
or metal oxide particles were found to be well-distributed on the coconut shell–derived biochar with the improvement in thermal stability and enlargement of specific surface area. A great reduction in band gap energy was observed in the composite materials after incorporating with the biochar. Among different biochar composites, g-C
3
N
4
/biochar was found to have the highest photocatalytic activity. The interactive effect of parameters such as catalyst dosage, peroxymonosulfate (PMS) oxidant dosage, and solution pH on the photocatalytic degradation of methyl orange was investigated using the response surface methodology (RSM). The highest photocatalytic degradation efficiency (96.63%) was achieved at catalyst dosage of 0.75 g/L, oxidant dosage of 0.6 mM, and solution pH 3 after 30 min.
Biodiesel from Jatropha curcas L. seed is conventionally produced via a two-step method: extraction of oil and subsequent esterification/transesterification to fatty acid methyl esters (FAME), ...commonly known as biodiesel. Contrarily, in this study, a single step in situ extraction, esterification and transesterification (collectively known as reactive extraction) of J. curcas L. seed to biodiesel, was investigated and optimized. Design of experiments (DOE) was used to study the effect of various process parameters on the yield of FAME. The process parameters studied include reaction temperature (30−60 °C), methanol to seed ratio (5−20 mL/g), catalyst loading (5−30 wt %), and reaction time (1−24 h). The optimum reaction condition was then obtained by using response surface methodology (RSM) coupled with central composite design (CCD). Results showed that an optimum biodiesel yield of 98.1% can be obtained under the following reaction conditions: reaction temperature of 60 °C, methanol to seed ratio of 10.5 mL/g, 21.8 wt % of H2SO4, and reaction period of 10 h.
The interest in using magnetic nanoparticle (MNPs) as a carrier for immobilization is overwhelming due to high surface area and lightweight properties. However, the conventional synthesis of MNPs ...required use of high amount of chemicals and is a time-consuming process. Thus, in the present research, magnetized multiwall carbon nanotubes (m-MWCNTs) were successfully synthesized via water-based system using simple steps. The synthesized m-MWCNTs was used as carrier for the immobilization of cellulase. Cellulase was proven to be successfully bounded on m-MWCNTs using Fourier transform infrared spectroscopy that revealed a peak at 580.33 cm
−1
indicating Fe–O stretching in parallel with observation of rougher and coarser surface of m-MWCNTs through scanning electron microscope. The total binding efficiency of cellulase to the m-MWCNTs was determined to be 95% at 5 mg/mL of the enzyme concentration. The activity of the immobilized cellulase was evaluated using carboxymethyl cellulose (CMC) as a substrate. Both of free and immobilized cellulase showed optimum working condition at 50 °C and pH 5. Furthermore, the immobilized cellulase was found to be able to retain more than 50% of its initial activity at the fifth cycle of the hydrolysis of CMC and filter paper. A similar activity was recorded with paddy straw at the third cycle of hydrolysis.
An important issue in synthesis of ion imprinted polymers (IIP) is optimization of the main parameters that involved during polymerization process as those parameters can influence the performance of ...IIP. In this study, IIP was synthesized by precipitation polymerization using allylthiourea (ATU) as monomer, nitrate as template ion, ethylene glycol dimethacrylate (EGDMA) as crosslinker, 2,2'-azobisisobutyronitrile (AIBN) as initiator with 365 nm ultraviolet (UV) light and mixture of acetonitrile and dimethylsulfoxide (DMSO) as porogenic solvent. The influences of various polymerization parameters in the synthesis of IIPs were investigated. The parameters studied included: ratio of monomer-template, amount of crosslinker and amount of porogenic solvent. These parameters were optimized using response surface methodology (RSM) coupled with central composite design CCD). Results showed that IIP with an optimum adsorption capacity of 156.233 mg/g of nitrate ion NO3−) can be obtained under the following polymerization conditions: 3.90 mmol of ATU, 18.67 mmol of EGDMA and 38.30 mL of porogenic solvent. The nitrate imprinted polymer and non-imprinted polymer were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The SEM micrograph showed microparticles ranging from 14.05 - 16.17 µm in diameter and the surface was rough and porous. The sorption of IIP followed Langmuir adsorption isotherm model. In this study, the binding capacity indicated that nitrate imprinted polymer recognized NO3− in aqueous solution more effectively compared to non-imprinted polymer and this polymer particles potrayed better adsorption as compared other adsorbent
Harum Manis mango leaves are considered lignocellulosic (LC) biomass that could contribute to the production of second generation (2G) bioethanol. However, pretreatment should be conducted to ...overcome the recalcitrance of LC biomass prior to bioethanol production. Hence, this study aims to elucidate the structural changes of the biomass of Harum Manis mango leaves after single-stage and two-stage chemical pretreatment. The Harum Manis mango leaves were treated with only acid, only alkaline, acid-alkaline, or alkaline-acid process. One per cent (v/v) sulphuric acid and 1% (w/v) sodium hydroxide were used as the acid and alkaline hydrolysing agent in the four approaches of pretreatment, respectively. Consequently, the pretreated biomass was enzymatically hydrolysed to produce reducing sugar followed by the conversion into bioethanol through yeast fermentation. Acid-alkaline pretreatment yielded the highest holocellulose composition of 95.26%, with the highest delignification effect of 86.97 ± 1.26%. Furthermore, Fourier transform infrared (FTIR) spectroscopy and X-ray powder diffraction (XRD) validated the acid-alkaline pretreated biomass to be the most feasible substrate for bioethanol production in this study. Finally, the maximum fermentable sugar content and bioethanol concentration of 415.02 ± 7.01 mg/g and 1.57 ± 0.06 mg/ml, respectively, were obtained.
The novel biodiesel production technology using supercritical reactive extraction from
Jatropha curcas L. oil seeds in this study has a promising role to fill as a more cost-effective processing ...technology. Compared to traditional biodiesel production method, supercritical reactive extraction can successfully carry out the extraction of oil and subsequent esterification/transesterification process to fatty acid methyl esters (FAME) simultaneously in a relatively short total operating time (45–80
min). Particle size of the seeds (0.5–2.0
mm) and reaction temperature/pressure (200–300
°C) are two primary factors being investigated. With 300
°C reaction temperature, 240
MPa operating pressure, 10.0
ml/g methanol to solid ratio and 2.5
ml/g of
n-hexane to seed ratio, optimum oil extraction efficiency and FAME yield can reach up to 105.3% v/v and 103.5% w/w, respectively which exceeded theoretical yield calculated based on
n-hexane Soxhlet extraction of Jatropha oil seeds.
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