Displaying publications 21 - 40 of 67 in total

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  1. Kinetic study on microwave-assisted esterification of free fatty acids derived from Ceiba pentandra Seed Oil
    Lieu T, Yusup S, Moniruzzaman M
    Bioresour Technol, 2016 Jul;211:248-56.
    PMID: 27019128 DOI: 10.1016/j.biortech.2016.03.105
    Recently, a great attention has been paid to advanced microwave technology that can be used to markedly enhance the biodiesel production process. Ceiba pentandra Seed Oil containing high free fatty acids (FFA) was utilized as a non-edible feedstock for biodiesel production. Microwave-assisted esterification pretreatment was conducted to reduce the FFA content for promoting a high-quality product in the next step. At optimum condition, the conversion was achieved 94.43% using 2wt% of sulfuric acid as catalyst where as 20.83% conversion was attained without catalyst. The kinetics of this esterification reaction was also studied to determine the influence of factors on the rate of reaction and reaction mechanisms. The results indicated that microwave-assisted esterification was of endothermic second-order reaction with the activation energy of 53.717kJ/mol.
    Matched MeSH terms: Sulfuric Acids
  2. Candida rugosa Lipase Immobilized onto Acid-Functionalized Multi-walled Carbon Nanotubes for Sustainable Production of Methyl Oleate
    Che Marzuki NH, Mahat NA, Huyop F, Buang NA, Wahab RA
    Appl Biochem Biotechnol, 2015 Oct;177(4):967-84.
    PMID: 26267406 DOI: 10.1007/s12010-015-1791-z
    The chemical production of methyl oleate using chemically synthesized fatty acid alcohols and other toxic chemicals may lead to significant environmental hazards to mankind. Being a highly valuable fatty acid replacement raw material in oleochemical industry, the mass production of methyl oleate via environmentally favorable processes is of concern. In this context, an alternative technique utilizing Candida rugosa lipase (CRL) physically adsorbed on multi-walled carbon nanotubes (MWCNTs) has been suggested. In this study, the acid-functionalized MWCNTs prepared using a mixture of HNO3 and H2SO4 (1:3 v/v) was used as support for immobilizing CRL onto MWCNTs (CRL-MWCNTs) as biocatalysts. Enzymatic esterification was performed and the efficiency of CRL-MWCNTs was evaluated against the free CRL under varying conditions, viz. temperature, molar ratio of acid/alcohol, solvent log P, and enzyme loading. The CRL-MWCNTs resulted in 30-110 % improvement in the production of methyl oleate over the free CRL. The CRL-MWCNTs attained its highest yield (84.17 %) at 50 °C, molar ratio of acid/alcohol of 1:3, 3 mg/mL of enzyme loading, and iso-octane (log P 4.5) as solvent. Consequently, physical adsorption of CRL onto acid-functionalized MWCNTs has improved the activity and stability of CRL and hence provides an environmentally friendly means for the production of methyl oleate.
    Matched MeSH terms: Sulfuric Acids
  3. Co3O4 nanocube-decorated nitrogen-doped carbon foam as an enhanced 3-dimensional hierarchical catalyst for activating Oxone to degrade sulfosalicylic acid
    Lin XR, Kwon E, Hung C, Huang CW, Oh WD, Lin KA
    J Colloid Interface Sci, 2021 Feb 15;584:749-759.
    PMID: 33176929 DOI: 10.1016/j.jcis.2020.09.104
    As sulfosalicylic acid (SUA) is extensively used as a pharmaceutical product, discharge of SUA into the environment becomes an emerging environmental issue because of its low bio-degradability. Thus, SO4--based advanced oxidation processes have been proposed for degrading SUA because of many advantages of SO4-. As Oxone represents a dominant reagent for producing SO4-, and Co is the most capable metal for activating Oxone to generate SO4-, it is critical to develop an effective but easy-to-use Co-based catalysts for Oxone activation to degrade SUA. Herein, a 3D hierarchical catalyst is specially created by decorating Co3O4 nanocubes (NCs) on macroscale nitrogen-doped carbon form (NCF). This Co3O4-decorated NCF (CONCF) is free-standing, macroscale and even squeezable to exhibit interesting and versatile features. More importantly, CONCF consists of Co3O4 NCs evenly distributed on NCF without aggregation. The NCF not only serves as a support for Co3O4 NCs but also offers additional active sites to synergistically enhance catalytic activities towards Oxone activation. Therefore, CONCF exhibits a higher catalytic activity than the conventional Co3O4 nanoparticles for activating Oxone to fully eliminate SUA in 30 min with a rate constant of 0.142 min-1. CONCF exhibits a much lower Ea value of SUA degradation (35.2 kJ/mol) than reported values, and stable catalytic activities over multi-cyclic degradation of SUA. The mechanism of SUA degradation is also explored, and degradation intermediates of SUA degradation are identified to provide a possible pathway of SUA degradation. These features validate that CONCF is certainly a promising 3D hierarchical catalyst for enhanced Oxone activation to degrade SUA. The findings obtained here are also insightful to develop efficient heterogeneous Oxone-activating catalysts for eliminating emerging contaminants.
    Matched MeSH terms: Sulfuric Acids
  4. Fulltext Bioethanol production from agarophyte red seaweed, Gelidium elegans, using a novel sample preparation method for analysing bioethanol content by gas chromatography
    Hessami MJ, Cheng SF, Ambati RR, Yin YH, Phang SM
    3 Biotech, 2019 Jan;9(1):25.
    PMID: 30622863 DOI: 10.1007/s13205-018-1549-8
    In this study, Gelidium elegans is investigated for ethanol production. A combination of factors including different temperatures, acid concentration and incubation time was evaluated to determine the suitable saccharification conditions. The combination of 2.5% (w/v) H2SO4 at 120 °C for 40 min was selected for hydrolysis of the seaweed biomass, followed by purification, and fermentation to yield ethanol. The galactose and glucose were dominant reducing sugars in the G. elegans hydrolysate and under optimum condition of dilute acid hydrolysis, 39.42% of reducing sugars was produced and fermentation resulted in ethanol concentration of 13.27 ± 0.47 g/L. A modified method was evaluated for sample preparation for gas chromatography (GC) analysis of the ethanol content. A solvent mixture of acetonitrile and iso-butanol precipitated dissolved organic residues and reduced water content in GC samples at least by 90%. Results showed that this method could be successfully used for bioethanol production from seaweed.
    Matched MeSH terms: Sulfuric Acids
  5. Supported liquid membrane extraction of nickel using stable composite SPEEK/PVDF support impregnated with a sustainable liquid membrane
    Sulaiman RNR, Jusoh N, Othman N, Noah NFM, Rosly MB, Rahman HA
    J Hazard Mater, 2019 12 15;380:120895.
    PMID: 31351388 DOI: 10.1016/j.jhazmat.2019.120895
    A sustainable and stable supported liquid membrane (SLM) extraction of nickel was developed via impregnation of sustainable liquid membrane in the composite membrane support consisting of polyvinylidene fluoride (PVDF) and sulfonated poly (ether ether ketone) (SPEEK). Bis-2-ethylhexyl phosphate (D2EHPA), 1-octanol, refined palm oil and sulfuric acid were employed as extractant, synergist extractant, diluent and strippant, respectively. Variables studied including effect of refined palm oil compositions as well as the configurations and thicknesses of SPEEK. Lifespan of SLM was evaluated by recycling the composite membrane support. Results revealed that upon using 100% refined palm oil, about 100% of nickel was extracted and recovered in 10 and 14 h, respectively. Composite SPEEK/PVDF stabilized SLM by reducing liquid membrane loss from 47 to 23% upon applying SPEEK at the feed side of PVDF support. High permeability and flux values were obtained at 9.26 x 10-4 cms-1 and 6.48 x 10-7 molcm-2s-1 when increasing SPEEK thickness from 0.025 to 0.055 mm, respectively. The lifespan of SLM was extended up to ninth cycles with low weight loss percentage of the impregnated composite membrane (8%). In conclusion, the SPEEK/PVDF impregnated with refined palm oil has improved the stability of SLM extraction of nickel ions from industrial wastewater.
    Matched MeSH terms: Sulfuric Acids
  6. Metal-complexed covalent organic frameworks derived N-doped carbon nanobubble-embedded cobalt nanoparticle as a magnetic and efficient catalyst for oxone activation
    Nguyen HT, Lee J, Kwon E, Lisak G, Thanh BX, Oh WD, et al.
    J Colloid Interface Sci, 2021 Jun;591:161-172.
    PMID: 33601102 DOI: 10.1016/j.jcis.2021.01.108
    While Cobalt nanoparticles (Co NPs) are useful for catalytic Oxone activation, it is more advantageous to embed/immobilize Co NPs on nitrogen-doped carbon substrates to provide synergy for enhancing catalytic performance. Herein, this study proposes to fabricate such a composite by utilizing covalent organic frameworks (COF) as a precursor. Through complexation of COF with Co, a stable product of Co-complexed COF (Co-COF) can be synthesized. This Co-COF is further converted through pyrolysis to N-doped carbon in which cobaltic NPs are embedded. Owing to its well-defined structures of Co-COF, the pyrolysis process transforms COF into N-doped carbon with a bubble-like morphology. Such Co NP-embedded N-doped carbon nanobubbles (CoCNB) with pores, magnetism and Co, shall be a promising catalyst. Thus, CoCNB shows a much stronger catalytic activity than commercial Co3O4 NPs to activate Oxone to degrade toxic Amaranth dye (AMD). CoCNB-activated Oxone also achieves a significantly lower Ea value of AMD degradation (i.e., 27.9 kJ/mol) than reported Ea values in previous literatures. Besides, CoCNB is still effective for complete elimination of AMD in the presence of high-concentration NaCl and surfactants, and CoCNB is also reusable over five consecutive cycles.
    Matched MeSH terms: Sulfuric Acids
  7. Fulltext Data on the absorbance of glucose during the acid hydrolysis of the sugarcane bagasse
    Alkarkhi AFM, Alqaraghuli WAA, Yusup Y, Abu Amr SS, Mahmud MN, Dewayantoa N
    Data Brief, 2019 Jun;24:103894.
    PMID: 31011604 DOI: 10.1016/j.dib.2019.103894
    This article presents data relating to the changes in absorbance of glucose during the acid hydrolysis of sugarcane bagasse using sulphuric acid. This dataset also contains the moisture content, volatile matter, and fixed carbon of the sugarcane bagasse. The results of the analysis of variance (ANOVA) and the interaction plots between reaction time, temperature, and ratio are also presented. The data revealed that absorbance of glucose is increasing by increasing the temperature and time. Moreover, the best ratio for the highest absorbance of glucose was achieved at 1:20.
    Matched MeSH terms: Sulfuric Acids
  8. Fulltext Effect of microwave-assisted acid or alkali pretreatment on sugar release from Dragon fruit foliage
    Ethaib, S., Omar, R., Mazlina, M., Radiah, A., Syafiie, S., Harun, M. Y.
    International Food Research Journal, 2016;23(101):149-154.
    MyJurnal
    Agriculture residues are a promising feedstock for value-added products from lignocellulosic waste. However, pretreatment of lignocellulosic materials is essential to facilitate enzymatic
    hydrolysis and improve sugar yield. The objective of this study is to evaluate the effect of acid or alkali during microwave-assisted pretreatment of dragon fruit foliage (DFF) that
    would make hydrolysis process more efficient. In the present study, distilled water and three chemicals were examined for their effects on releasing monomeric sugar during microwave
    treatment. Microwave-assisted pretreatment namely microwave-distilled water (M-H2O) (control); microwave-sulfuric acid (M-H2SO4); microwave-sodium hydroxide (M-NaOH); and
    microwave-sodium bicarbonate (M-NaHCO3) pretreatment were performed using 5% (w/v) of DFF as substrate at 800 watt microwave power for 5 minutes exposure time. Highest yield
    of monomeric sugar was found at 15.56 mg/g using M-NaOH pretreatment at 0.1N NaOH. For M-H2SO4 pretreatment, 0.1N H2SO4 produced 8.2 mg/g of monomeric sugar. Application
    of M-NaHCO3 pretreatment using 0.05N NaHCO3 solution released 6.45 mg/g of monomeric sugar. While, soaking DFF in distilled water and subjecting to microwave irradiation released
    6.6 mg/g of monomeric sugar. Treatments with the lowest concentration (0.01 N) of the three chemicals released only small quantities of total monomeric sugars and less than that with distilled water. The changes in the physical structure of DFF prior to and after the microwaveassisted pretreatment are also reported.
    Matched MeSH terms: Sulfuric Acids
  9. Fulltext Enhanced Co2 removal using polyethersulfone incorporated with beta-cyclodextrin/carbon nanotubes
    Goh, P.S., Ismail, A.F., Ng, B.C., Sumner, T.
    ASM Science Journal, 2014;8(2):125-133.
    MyJurnal
    This study was conducted to prepare a mixed matrix membrane (MMM) and to test the performance of the prepared MMM for CO2 and CH4 gas separation. MMM containing polyethersulfone (PES) and multi-walled carbon nanotubes (MWCNTs) was prepared by a dry-wet phase inversion technique using a pneumatically-controlled membrane casting machine. The surface modification was performed on MWCNTs in order to enhance the selectivity of CO2/CH4. The surface modification of MWCNTs using chemical and physical approaches has been adopted. Mixed acid (HNO3/H2SO4) and β-CD were used for chemical and physical approaches, respectively. Effects of surface modification on MWCNTs/PES MMM were investigated. MWCNTs/PES MMMs were characterised using scanning electron microscopy (SEM), the Fourier Transform Infrared (FT-IR) spectroscopy and pure gas permeation test. The permeability and selectivity, which are the parameters describing membrane performance were calculated via the data obtained from pure gas permeation test with the feed pressure difference from 3 to 7 bars. In this study, surface modified MWCNTs/PES MMM using mixed acid and β-CD has successfully enhanced the CO2/CH4 selectivity by 40.6% compared to that of neat PES.
    Matched MeSH terms: Sulfuric Acids
  10. Fulltext Study of anodised PM aluminium matrix composite reinforced with 15 wt % saffil™ alumina short fibre
    Mohd Nazree Derman, Zainal Arifin Ahmad, Hussain, Luay Bakir, Nurulakmal Mohd Sharif
    Journal of Nuclear and Related Technologies, 2007;2007(1):155-158.
    MyJurnal
    A study of wear behaviour on anodised PM aluminium matrix composites (AMC) reinforced with Saffil™ alumina short fibres was done. AMC was fabricated by powder metallurgy methods (PM) with using Al flake powders and Saffil™ alumina short fibres. AMC reinforced with 15 wt % Saffil¥ alumina short fibre was selected because it showed optimum mechanical and physical properties. Sulphuric acid anodising process was performed and the objective is to obtain suitable parameters of sulphuric acid concentration, anodising voltage and anodising time on MMC. The study of anodising process was carried out with various sulphuric acid concentrations (from 0 to 20 % volume), anodising voltage (10 V to 20 V) and anodising time (from 0 to 60 minutes) at room temperature. Scanning electron microscope (SEM) was used to investigate coating morphology and thickness. From the research, anodising voltage of 18 V and 15 % vol H2SO4 in anodising time of 60 minutes were suitable parameters for sulphuric acid anodising of this AMC. SEM showed the coating thickness around 20 Pm. From the reserch, it was found that H2SO4 anodising was able to give good coating to MMC.
    Matched MeSH terms: Sulfuric Acids
  11. Penspesiesan Ion-ion Ferum dengan Resin Poli (Asid Hidroksamik)(Speciation of Iron Ions Using Poly(Hydroxamic Acid)) Resin
    Wan Md Zin Wan Yunus, Md Jelas Haron
    Sains Malaysiana, 1996;25.
    Poly(hydroxamic acid) ion exchange resin was evaluated for speciation of iron(II) and iron(III) ions. Distribution coefficients indicate that the resin is more selective towards iron(III) ion. Column extractions show that iron(III) ion is quantatively extracted from sulfuric acid solutions at concentrations of between 0.01 to 0.00lM but only 2% or less of iron(II) ion is retained under these conditions. Further studies show that these two ions can be separated and their separations are not affected by the presence of nickel, zinc, copper, calcium, chloride, bromide, nitrate and sulphate.
    Resin penukar ion poli(asid hidroksamik) telah dikaji untuk penspesiesan ion-ionferum. Pekali taburan menunjukkan resin ini mempunyai kepilihan yang tinggi terhadap ion ferik berbanding dengan ionferus. Pengekstrakan dengan kaedah turus mendapati ion ferik dari larutan asid sulfurik 0.01 dan 0.00lM boleh diesktrak secara kuantitatif manakala pengekstrakan ion ferus hanya 2% atau lebih kecil. Kajian lanjut menunjukkan resin ini boleh memisahkan ion ferik dari ion ferus dan pemisahan ini tidak diganggu oleh kehadiran ion-ion nikel, zink, kuprum, kalsium, klorida, bromida, nitrat dan sulfat.
    Matched MeSH terms: Sulfuric Acids
  12. Characterization of residue from EFB and kenaf core fibres in the liquefaction process
    Sarani Zakaria, Rasidi Roslan, Umar Adli Amran, Chia CH, Saiful Bahari Bakaruddin
    Sains Malaysiana, 2014;43:429-435.
    Different type of fibers which is EFB and KC were liquefied in phenol with the presence of sulphuric acid as a catalyst. The liquefied residue was characterized by using Fourier transform infrared (FTIR) to determine the functional groups presents in both residues, X-ray diffraction (XRD) to determine the degree of crystallinity in the residue, thermogravimetric analysis (TGA) to analyze the thermal properties of the residue and scanning electron microscope (SEM) to investigate the structure and morphology of the residue. Phenol-to-EFB/KC ratio shows great effect on the amount of residue in the liquefaction process. Peak appearance can be observed in the FTIR analysis at 810 and 750 cm-1 which is attributed to the para and meta benzene, respectively or to be specific its associated to the p-alkyl phenol and m-alkyl phenol. In the XRD analysis, CrI of lignocellulosic materials increased after liquefaction process. Liquefaction process caused chemical penetration across the grain of the fiber, thus the fiber bundles started to separate into individual fibers shown in the SEM micrograph and the weights lost curve for both liquefied EFB and KC experienced three region decompositions.
    Matched MeSH terms: Sulfuric Acids
  13. Fulltext Determination of the Major Component of Water Fraction of Katuk (Sauropus androgynous (L.) Merr.) Leaves by Liquid Chromatography-Mass Spectrometry
    Mustarichie R, Salsabila T, Iskandar Y
    J Pharm Bioallied Sci, 2019 Dec;11(Suppl 4):S611-S618.
    PMID: 32148372 DOI: 10.4103/jpbs.JPBS_205_19
    Background: The katuk leaf (Sauropus androgynous (L.) Merr.) is one of the plants that are used to overcome baldness by the people of Kampung Mak Kemas, Malaysia. It is suspected that secondary metabolites contained in katuk leaves play a key role in stimulating hair growth.

    Aims and Objectives: The aim of this study was to identify the optimum method to obtain one of the chemical compounds in the water fraction and to identify the hypothesized chemical isolates in the water fraction katuk leave's ethanol extract.

    Materials and Methods: The methods used in this study included the collection and determination of the katuk plant, the processing of the katuk, phytochemical filtrating, extracting with ethanol 96%, and fractionation using the liquid-liquid extraction method with n-hexane, ethyl acetate, and water solvents The water fraction of katuk leaves was analyzed by its components by thin-layer chromatography using the stationary phase of silica gel 60 F254, developer of n-butanol:acetic acid:water (4:1:5), and detection under ultraviolet (UV) light at a wavelength of 366 and 254nm, as well as with vanillin-sulfuric acid reagent. To isolate the compounds from water fraction of katuk leaves, it was then eluted with a vacuum column chromatography by eluent with a level polarity that would get 11 subfractions. Each subfraction was checked by two-dimensional thin-layer chromatography to see subfraction purity characterized by the appearance of a spot on the chromatogram plate. The isolate was analyzed using spot test, ultraviolet-visible spectrophotometer, infrared spectrophotometer, and liquid chromatography-mass spectrometry.

    Results: The isolate was an alkaloid compound with a molecular mass of 406.3131 m/z with the molecular formula C21H39N6O2 as S, S-5, 5'-amino-4,4'-dihexyl-propyldihydropyrazol-3, 3-one.

    Conclusion: One of the chemical compounds contained in the water fraction of the ethanol extract of the katuk leaf was an alkaloid group.

    Matched MeSH terms: Sulfuric Acids
  14. Esterification of levulinic acid to levulinate esters in the presence of sulfated silica catalyst
    Nur Aainaa Syahirah Ramli, Nur Irsalina Hisham, Nor Aishah Saidina Amin
    Sains Malaysiana, 2018;47:1131-1138.
    Levulinic acid (LA) is one of biomass derived building block chemicals with various applications. Catalytic esterification
    of LA with alkyl alcohol produces levulinate ester which can be applied as fragrance, flavouring agents, as well as fuel
    additives. In this study, a series of sulfated silica (SiO2
    ) catalyst was prepared by modification of SiO2
    with sulfuric acid
    (H2
    SO4
    ) at different concentrations; 0.5 M to 5 M H2
    SO4
    . The catalysts were characterized, and tested for esterification
    of LA with ethanol to ethyl levulinate (EL). The effect of various reaction parameters including reaction time, catalyst
    loading and molar ratio of LA to ethanol on esterification of LA to EL were inspected. The catalyst with high concentration
    of acid sites seemed suitable for LA esterification to EL. Among the sulfated SiO2
    catalysts tested (0.5 M-SiO2
    , 1 M-SiO2
    ,
    3 M-SiO2
    and 5 M-SiO2
    ), 3 M-SiO2
    exhibited the highest performance with the optimum EL yield of 54% for reaction
    conducted at reflux temperature for 4 h, 30% 3 M-SiO2
    loading and LA to ethanol molar ratio of 1:20. Besides, the
    reusability of 3 M-SiO2
    catalyst for LA esterification with ethanol was examined for five cycles. Esterification of LA with
    methanol and 1-butanol were also carried out for methyl levulinate (ML) and butyl levulinate (BL) productions with 69%
    and 40% of ML and BL yields, respectively. This study demonstrates the potential of sulfated SiO2
    catalyst for levulinate
    ester production from LA at mild process condition.
    Matched MeSH terms: Sulfuric Acids
  15. Coordination polymer-derived cobalt-embedded and N/S-doped carbon nanosheet with a hexagonal core-shell nanostructure as an efficient catalyst for activation of oxone in water
    Tuan DD, Oh WD, Ghanbari F, Lisak G, Tong S, Andrew Lin KY
    J Colloid Interface Sci, 2020 Nov 01;579:109-118.
    PMID: 32574728 DOI: 10.1016/j.jcis.2020.05.033
    As sulfate-radical (SR)-based advanced oxidation processes are increasingly implemented, Oxone has been frequently-used for generation of SR. While Co3O4 nanoparticle (NP) has been widely-accepted as a promising catalyst for activating Oxone, Co3O4 NPs tend to aggregate in water, losing their reactivity. Thus, many attempts have immobilized Co3O4 NPs on supports, especially carbonaceous substrates, because combination of Co NPs with carbon substrates offers synergistic effects for boosting catalytic activities. Moreover, carbon substrates doped with hetero-atoms (N and S) further increase electron transfer and reactivity. Therefore, it is even promising to immobilize Co NPs onto N/S-doped carbon (NSC) to form Co-embedded NSC (denoted as CoNSC) for enhancing Oxone activation. In this study, a convenient and facile technique is proposed to prepare such a CoNSC via a simple carbonization treatment of a coordination polymer of Co and trithiocyanuric acid (TTCA). The resulting CoNSC exhibits the sheet-like hexagonal morphology with the core-shell configuration, and Co NPs are well-embedded into the N/S-doped carbonaceous matrix, making it an advantageous heterogeneous catalyst for Oxone activation. As Azorubine S (ARS) decolorization is employed as a model reaction of Oxone activation, CoNSC exhibits a higher catalytic activity than pristine Co3O4 and NSC for Oxone activation to decolorize ARS. In comparison to the other reported catalysts, CoNSC also possesses a much lower Ea for ARS decolorization. CoNSC can be also reusable and stable for Oxone activation over multiple cycles without loss of catalytic activity. These features validate that CoNSC is a promising and useful Co-based catalyst for Oxone activation.
    Matched MeSH terms: Sulfuric Acids
  16. Pretreatment of extruded Napier grass byhydrothermal process with dilute sulfuric acid and fermentation using a cellulose-hydrolyzing and xylose-assimilating yeast for ethanol production
    Ismail KSK, Matano Y, Sakihama Y, Inokuma K, Nambu Y, Hasunuma T, et al.
    Bioresour Technol, 2022 Jan;343:126071.
    PMID: 34606923 DOI: 10.1016/j.biortech.2021.126071
    One of the potential bioresources for bioethanol production is Napier grass, considering its high cellulose and hemicellulose content. However, the cost of pretreatment hinders the bioethanol produced from being economical. This study examines the effect of hydrothermal process with dilute acid on extruded Napier grass, followed by enzymatic saccharification prior to simultaneous saccharification and co-fermentation (SScF). Extrusion facilitated lignin removal by 30.2 % prior to dilute acid steam explosion. Optimum pretreatment condition was obtained by using 3% sulfuric acid, and 30-min retention time of steam explosion at 190 °C. Ethanol yield of 0.26 g ethanol/g biomass (60.5% fermentation efficiency) was attained by short-term liquefaction and fermentation using a cellulose-hydrolyzing and xylose-assimilating Saccharomyces cerevisiae NBRC1440/B-EC3-X ΔPHO13, despite the presence of inhibitors. This proposed method not only reduced over-degradation of cellulose and hemicellulose, but also eliminated detoxification process and reduced cellulase loading.
    Matched MeSH terms: Sulfuric Acids
  17. Application of acid-modified Imperata cylindrica powder for latent fingerprint development
    Low WZ, Khoo BE, Aziz ZB, Low LW, Teng TT, bin Abdullah AF
    Sci Justice, 2015 Sep;55(5):347-54.
    PMID: 26385718 DOI: 10.1016/j.scijus.2015.04.008
    A novel powdering material that utilizes acid-modified Imperata cylindrica (IC) powder for the development of fingermarks was studied. Experiments were carried out to determine the suitability, adherence quality and sensitivity of the acid-modified IC powder. Fingermarks of different constituents (eccrine, sebaceous and natural fingermarks) on different types of surfaces were used. Acid-modified IC powder was also used to develop fingermarks of different ages as well as aged fingermarks recovered from the water. From the visual inspection, acid-modified IC powder was able to interact with different fingermark constituents and produced distinct ridge details on the examined surfaces. It was also able to develop aged fingermarks and fingermarks that were submerged in water. A statistical comparison was made against the Sirchie® Hi-Fi black powder in terms of the powders' sensitivity and quality of the developed natural fingermarks. The image quality was analyzed using MITRE's Image Quality of Fingerprint (IQF) software. From the experiments, acid-modified IC powder has the potential as a fingermark development powder, although natural fingermarks developed by Sirchie® black powder showed better quality and sensitivity based on the results of the statistical comparison.
    Matched MeSH terms: Sulfuric Acids
  18. Fulltext Impact of Sulfuric Acid Treatment of Halloysite on Physico-Chemic Property Modification
    Gaaz TS, Sulong AB, Kadhum AAH, Nassir MH, Al-Amiery AA
    Materials (Basel), 2016 Jul 26;9(8).
    PMID: 28773741 DOI: 10.3390/ma9080620
    Halloysite (HNT) is treated with sulfuric acid and the physico-chemical properties of its morphology, surface activity, physical and chemical properties have been investigated when HNT is exposed to sulfuric acid with treatment periods of 1 h (H1), 3 h (H3), 8 h (H8), and 21 h (H21). The significance of this and similar work lies in the importance of using HNT as a functional material in nanocomposites. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR). The spectrum demonstrates that the hydroxyl groups were active for grafting modification using sulfuric acid, promoting a promising potential use for halloysite in ceramic applications as filler for novel clay-polymer nanocomposites. From the X-ray diffraction (XRD) spectrum, it can be seen that the sulfuric acid breaks down the HNT crystal structure and alters it into amorphous silica. In addition, the FESEM images reveal that the sulfuric acid treatment dissolves the AlO₆ octahedral layers and induces the disintegration of SiO₄ tetrahedral layers, resulting in porous nanorods. The Bruncher-Emmett-Teller (BET) surface area and total pore volume of HNTs showed an increase. The reaction of the acid with both the outer and inner surfaces of the nanotubes causes the AlO₆ octahedral layers to dissolve, which leads to the breakdown and collapse of the tetrahedral layers of SiO₄. The multi-fold results presented in this paper serve as a guide for further HNT functional treatment for producing new and advanced nanocomposites.
    Matched MeSH terms: Sulfuric Acids
  19. Potential of Ceiba pentandra (L.) Gaertn. (kapok) fiber as a resource for second generation bioethanol: parametric optimization and comparative study of various pretreatments prior enzymatic saccharification for sugar production
    Tye YY, Lee KT, Abdullah WN, Leh CP
    Bioresour Technol, 2013 Jul;140:10-14.
    PMID: 23672935 DOI: 10.1016/j.biortech.2013.04.069
    Various pretreatments on Ceiba pentandra (L.) Gaertn. (kapok) fiber prior to enzymatic hydrolysis for sugar production were optimized in this study. The optimum conditions for water, acid, and alkaline pretreatments were 170°C for 45 min, 120°C for 45 min in 1.0% (v/v) H2SO4 solution and 120°C for 60 min in 2.0% (v/v) NaOH solution, respectively. Among the three pretreatments, the alkaline pretreatment achieved the highest total glucose yield (glucose yield calculated based on the untreated fiber) (38.5%), followed by the water (35.0%) and acid (32.8%) pretreatments. As a result, the relative effectiveness of the pretreatment methods for kapok fiber was verified as alkali>water>acid at the condition stated.
    Matched MeSH terms: Sulfuric Acids/pharmacology
  20. Enhanced xylose recovery from oil palm empty fruit bunch by efficient acid hydrolysis
    Tan HT, Dykes GA, Wu TY, Siow LF
    Appl Biochem Biotechnol, 2013 Aug;170(7):1602-13.
    PMID: 23709290 DOI: 10.1007/s12010-013-0298-8
    Oil palm empty fruit bunch (EFB) is abundantly available in Malaysia and it is a potential source of xylose for the production of high-value added products. This study aimed to optimize the hydrolysis of EFB using dilute sulfuric acid (H2SO4) and phosphoric acid (H3PO4) via response surface methodology for maximum xylose recovery. Hydrolysis was carried out in an autoclave. An optimum xylose yield of 91.2 % was obtained at 116 °C using 2.0 % (v/v) H2SO4, a solid/liquid ratio of 1:5 and a hydrolysis time of 20 min. A lower optimum xylose yield of 24.0 % was observed for dilute H3PO4 hydrolysis at 116 °C using 2.4 % (v/v) H3PO4, a solid/liquid ratio of 1:5 and a hydrolysis time of 20 min. The optimized hydrolysis conditions suggested that EFB hydrolysis by H2SO4 resulted in a higher xylose yield at a lower acid concentration as compared to H3PO4.
    Matched MeSH terms: Sulfuric Acids/chemistry*
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