Displaying publications 1 - 20 of 67 in total

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  1. Acetic acid as a protic solvent for reducing sulphuric acid concentrations in the production of cellulose nanocrystals alongside transition metal co-catalysts
    Lim CSS, Chan EWC, Wong CW
    Int J Biol Macromol, 2024 Feb;259(Pt 2):129303.
    PMID: 38216018 DOI: 10.1016/j.ijbiomac.2024.129303
    Cellulose nanocrystals (CNC) conventionally involve highly concentrated sulphuric acid, which typically resulted in the formation of undesirable by-products. Although less corrosive mineral acids have been explored as alternatives, high concentrations are still required. In this study, CNC was successfully isolated from Leucaena leucocephala wood using mild sulphuric acid with acetic acid as protic solvent, and it was further studied with the addition of Lewis acids in the form of multivalent transition metal salts as co-catalyst. Selected divalent and trivalent transition metal salts including (Cr(NO3)3, Fe(NO3)3, Co(NO3)2, and Ni(NO3)2) were investigated. The morphology, chemical structure, particle size, and physicochemical properties of the CNCs were determined. Controlled depolymerization of cellulose was observed using transmission electron microscopy (TEM). Rod-like morphology for all CNCs was obtained during the hydrolysis process with the smallest CNC particles found at an average length of 278.1 ± 35.1 nm and a diameter of 13.4 ± 3.0 nm. The results showed that higher valence state metal ions resulted in better cellulose hydrolysis efficiency. In addition, the use of transition metal salt as a co-catalyst improved production efficiency and minimised carbonization of CNC while maintaining desired crystallinity and thermal properties.
    Matched MeSH terms: Sulfuric Acids/chemistry
  2. Acetylation of glycerol to biofuel additives over sulfated activated carbon catalyst
    Khayoon MS, Hameed BH
    Bioresour Technol, 2011 Oct;102(19):9229-35.
    PMID: 21840708 DOI: 10.1016/j.biortech.2011.07.035
    Oxygenated fuel additives can be produced by acetylation of glycerol. A 91% glycerol conversion with a selectivity of 38%, 28% and 34% for mono-, di- and triacetyl glyceride, respectively, was achieved at 120 °C and 3 h of reaction time in the presence of a catalyst derived from activated carbon (AC) treated with sulfuric acid at 85 °C for 4h to introduce acidic functionalities to its surface. The unique catalytic activity of the catalyst, AC-SA5, was attributed to the presence of sulfur containing functional groups on the AC surface, which enhanced the surface interaction between the glycerol molecule and acyl group of the acetic acid. The catalyst was reused in up to four consecutive batch runs and no significant decline of its initial activity was observed. The conversion and selectivity variation during the acetylation is attributed to the reaction time, reaction temperature, catalyst loading and glycerol to acetic acid molar ratio.
    Matched MeSH terms: Sulfuric Acids/metabolism
  3. Acid-activated spent bleaching earth as a sorbent for chromium (VI) in aqueous solution
    Low KS, Lee CK, Lee TS
    Environ Technol, 2003 Feb;24(2):197-204.
    PMID: 12675017
    Spent bleaching earth, an industrial waste produced after the bleaching of crude palm oil, was investigated for its potential in removing Cr(VI) from aqueous solution. The earth was treated with different amounts of sulfuric acid and under different activation temperatures. Results show that the optimum treatment process involved 10% sulfuric acid at 350 degrees C. The effects of contact time, pH, initial concentration, sorbent dosage, temperature, sorption isotherms and the presence of other anions on its sorption capacity were studied. Isotherm data could be fitted into a modified Langmuir isotherm model implying monolayer coverage of Cr(VI) on acid activated spent bleaching earth. The maximum sorption capacity derived from the Langmuir isotherm was 21.2 mg g(-1). This value was compared with those of some other low cost sorbents. Studies of anion effect on the uptake of Cr(VI) on acid activated spent bleaching earth provided the following order of suppression: EDTA >PO4(3-)>SO4(2-)>NO3(-)>Cl(-).
    Matched MeSH terms: Sulfuric Acids
  4. Fulltext An overview of bacterial concrete on concrete durability in aggressive environment
    Irwan, J.M., Teddy, T.
    Pertanika Journal of Science & Technology, 2017;25(105):259-264.
    MyJurnal
    Concrete durability determines service life of structures. It can though, be weakened by aggressive environmental conditions. For instance, bio-corrosion process is due to the presence and activity of microorganisms which produce sulphuric acid to form sulphate deterioration of concrete materials. The problems related to durability and repair systems are due to lack of suitable concrete materials. The use bacteria for concrete repairing and plugging of pores and cracking in concrete has been recently explored. Previous studies had proved the possibility of using specific bacteria via bio concrete as a sustainable method for improving concrete properties. Thus, lack of information on the application of bio concrete exposed to extreme condition was the motivation for this research.
    Matched MeSH terms: Sulfuric Acids
  5. Analysis of biofilms formation by cronobacter sp. During growth in infant formula milk
    Aishah Faiqah Mohd Yusof, Prabhakaran P, Nur Diyana Azli, Norrakiah Abdullah Sani, Wan Syaidatul Aqma
    Sains Malaysiana, 2017;46:903-908.
    Pacifier nipples are in permanent contact with saliva and with the oral microflora therefore, act as a favoured site for the growth of biofilms. This research was conducted to identify the bacterial biofilms that has been found on the pacifiers that collected from local child nursery and to analyse the formation of biofilms by Cronobacter sp. during growth in infant formula milk. Pacifiers collected were analysed to obtain colony forming unit (CFU) and isolated bacteria were identified using several biochemical tests according to Bergey's Manual. Biofilm assay of three Cronobacter sp. were conducted using 24 wells microtiter plate and stained with 1% of crystal violet solution at different time interval: 6, 12, 18 and 24 h. The hydrophobicity of the bacterial cell suspension was evaluated using bacterial adhesion to hydrocarbons (BATH) method. Extracellular polymeric substances (EPS) analysis was done to identify percentage of carbohydrate and protein content by using phenol sulphuric acid method and Bradford method, respectively. The results obtained showed that the normal microflora bacteria were the most abundant microorganisms that were found on the pacifier with the main genus isolated was Staphylococcus sp., Enterobacteriaceae sp. and Clostridium sp. Based on biofilm and EPS analysis, Cronobacter sakazakii formed a strong biofilms after 18 h, with carbohydrate was identified as main component of EPS.
    Matched MeSH terms: Sulfuric Acids
  6. 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
  7. 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
  8. Biphasic pretreatment excels over conventional sulfuric acid in pinewood biorefinery: An environmental analysis
    Khounani Z, Abdul Razak NN, Hosseinzadeh-Bandbafha H, Madadi M, Sun F, Mohammadi P, et al.
    Environ Res, 2024 May 01;248:118286.
    PMID: 38280524 DOI: 10.1016/j.envres.2024.118286
    This study assesses the environmental impact of pine chip-based biorefinery processes, focusing on bioethanol, xylonic acid, and lignin production. A cradle-to-gate Life Cycle Assessment (LCA) is employed, comparing a novel biphasic pretreatment method (p-toluenesulfonic acid (TsOH)/pentanol, Sc-1) with conventional sulfuric acid pretreatment (H2SO4, Sc-2). The analysis spans biomass handling, pretreatment, enzymatic hydrolysis, yeast fermentation, and distillation. Sc-1 yielded an environmental impact of 1.45E+01 kPt, predominantly affecting human health (96.55%), followed by ecosystems (3.07%) and resources (0.38%). Bioethanol, xylonic acid, and lignin contributed 32.61%, 29.28%, and 38.11% to the total environmental burdens, respectively. Sc-2 resulted in an environmental burden of 1.64E+01 kPt, with a primary impact on human health (96.56%) and smaller roles for ecosystems (3.07%) and resources (0.38%). Bioethanol, xylonic acid, and lignin contributed differently at 22.59%, 12.5%, and 64.91%, respectively. Electricity generation was predominant in both scenarios, accounting for 99.05% of the environmental impact, primarily driven by its extensive usage in biomass handling and pretreatment processes. Sc-1 demonstrated a 13.05% lower environmental impact than Sc-2 due to decreased electricity consumption and increased bioethanol and xylonic acid outputs. This study highlights the pivotal role of pretreatment methods in wood-based biorefineries and underscores the urgency of sustainable alternatives like TsOH/pentanol. Additionally, adopting greener electricity generation, advanced technologies, and process optimization are crucial for reducing the environmental footprint of waste-based biorefineries while preserving valuable bioproduct production.
    Matched MeSH terms: Sulfuric Acids*
  9. Bone regeneration performance of surface-treated porous titanium
    Amin Yavari S, van der Stok J, Chai YC, Wauthle R, Tahmasebi Birgani Z, Habibovic P, et al.
    Biomaterials, 2014 Aug;35(24):6172-81.
    PMID: 24811260 DOI: 10.1016/j.biomaterials.2014.04.054
    The large surface area of highly porous titanium structures produced by additive manufacturing can be modified using biofunctionalizing surface treatments to improve the bone regeneration performance of these otherwise bioinert biomaterials. In this longitudinal study, we applied and compared three types of biofunctionalizing surface treatments, namely acid-alkali (AcAl), alkali-acid-heat treatment (AlAcH), and anodizing-heat treatment (AnH). The effects of treatments on apatite forming ability, cell attachment, cell proliferation, osteogenic gene expression, bone regeneration, biomechanical stability, and bone-biomaterial contact were evaluated using apatite forming ability test, cell culture assays, and animal experiments. It was found that AcAl and AnH work through completely different routes. While AcAl improved the apatite forming ability of as-manufactured (AsM) specimens, it did not have any positive effect on cell attachment, cell proliferation, and osteogenic gene expression. In contrast, AnH did not improve the apatite forming ability of AsM specimens but showed significantly better cell attachment, cell proliferation, and expression of osteogenic markers. The performance of AlAcH in terms of apatite forming ability and cell response was in between both extremes of AnH and AsM. AcAl resulted in significantly larger volumes of newly formed bone within the pores of the scaffold as compared to AnH. Interestingly, larger volumes of regenerated bone did not translate into improved biomechanical stability as AnH exhibited significantly better biomechanical stability as compared to AcAl suggesting that the beneficial effects of cell-nanotopography modulations somehow surpassed the benefits of improved apatite forming ability. In conclusion, the applied surface treatments have considerable effects on apatite forming ability, cell attachment, cell proliferation, and bone ingrowth of the studied biomaterials. The relationship between these properties and the bone-implant biomechanics is, however, not trivial.
    Matched MeSH terms: Sulfuric Acids/pharmacology
  10. 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
  11. 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
  12. Chromium(III) sorption enhancement through NTA--modification of biological materials
    Low KS, Lee CK, Lee PL
    Bull Environ Contam Toxicol, 1997 Mar;58(3):380-6.
    PMID: 9008046
    Matched MeSH terms: Sulfuric Acids/chemistry
  13. 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
  14. Combination of gamma irradiation and sodium carbonate pretreatment on oil palm empty fruit bunch (efb) for high acidic hydrolysis yield
    Siew XC, Chin HC, Sarani Zakaria, Sahrim Ahmad, Siti Masrinda Tasirin
    Sains Malaysiana, 2017;46:167-173.
    Oil palm empty fruit bunch (EFB) fibres were pretreated by gamma irradiation followed by sodium carbonate (Na2
    CO3
    )
    before the acid hydrolysis process to produce reducing sugars using diluted sulphuric acid (H2
    SO4
    ). In this study, EFB
    fibres were irradiated at different doses, i.e. 0, 100 and 200 kGy. Meanwhile, the gamma irradiated sample were then
    subjected to Na2
    CO3 pretreatment with 0 and 5% total titratable alkali (TTA). The effect of the pretreatment using gamma
    irradiation and Na2
    CO3
    on the physical and chemical properties of the EFB fibres and the yield of the reducing sugar
    obtained from the acid hydrolysis process was investigated. The obtained results showed that the content of holocellulose
    was increased significantly with the increase of irradiation doses combined with Na2
    CO3 pretreatment, whereas lignin
    content of the EFB was decreased. The gamma irradiation and Na2
    CO3 pretreatment resulted in structure breakage
    and removal of silica of EFB fibres which can be due to the swelling of the fibres. A synergistic effect between gamma
    irradiation and Na2
    CO3 was observed, in which the yield of reducing sugars was increased by combining the gamma
    irradiation and Na2
    CO3 pretreatment.
    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. 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
  17. Fulltext Determination of elements (Cd, Cu, Fe, Pb and Zn) in Universiti Teknologi MARA (UiTM) Hostel Shah Alam, Malaysia
    Nurzulaifa Shaheera Erne Mohd Yasim, Siti Khadijah Mat Yaacob, Noradila Mohamed
    Science Letters, 2018;12(2):28-36.
    MyJurnal
    The purpose of this study is to determine the concentration of the selected elemental composition in a multi-storey hostel. Dust samples were taken from three random rooms at each level of the student hostel by sweeping the floor. The concentrations of elements (Cd, Cu, Fe, Pb and Zn) were determined by using Inductively Coupled Plasma-Optical Emission Spectrometer (ICPOES) after digestion with nitric acid and sulfuric acid solutions. Dust samples analysis has shown the different levels of sampling point does not affect the concentration of the elements. The concentration of elements in investigated microenvironment was in the order of Fe > Zn > Cu > Pb > Cd. The correlation analysis was applied to elements variable in order to identify the sources of an airborne contaminant. It was discovered the strong positive correlation between Cu-Zn which indicates the sources come from traffic emission and street dust. This result was supported by the Principal Component Analysis (PCA) that revealed the presence of elements in the student hostel originated from the outdoor sources.
    Matched MeSH terms: Sulfuric Acids
  18. Determination of silver, bismuth, cadmium, copper, iron, nickel and zinc in lead- and tin-base solders and white-metal bearing alloys by atomic-absorption spectrophotometry
    Chong C
    Talanta, 1986 Jan;33(1):91-4.
    PMID: 18964038
    A simple atomic-absorption spectrophotometry method is described for the determination of silver, bismuth, cadmium, copper, iron, nickel and zinc in lead- and tin-base solders and white-metal bearing alloys, with use of a single sample solution. The sample is dissolved in a mixture of hydrobromic acid and bromine, then fumed with sulphuric acid. The lead sulphate is dissolved in concentrated hydrochloric acid. The method is particularly suitable for the determination of silver and bismuth, which are co-precipitated with lead sulphate. The other elements can also be determined after removal of the lead sulphate by filtration.
    Matched MeSH terms: Sulfuric Acids
  19. 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
  20. Development of 3-dimensional Co3O4 catalysts with various morphologies for activation of Oxone to degrade 5-sulfosalicylic acid in water
    Li MH, Da Oh W, Lin KA, Hung C, Hu C, Du Y
    Sci Total Environ, 2020 Jul 01;724:138032.
    PMID: 32408427 DOI: 10.1016/j.scitotenv.2020.138032
    Since 5-sulfosalicylic acid (SFA) has been increasingly released to the environment, SO4--based oxidation processes using Oxone have been considered as useful methods to eliminate SFA. As Co3O4 has been a promising material for OX activation, the four 3D Co3O4 catalysts with distinct morphologies, including Co3O4-C (with cubes), Co3O4-P (with plates), Co3O4-N (with needles) and Co3O4-F (with floral structures), are fabricated for activating OX to degrade SFA. In particular, Co3O4-F not only exhibits the highest surface area but also possesses the abundant Co2+ and more reactive surface, making Co3O4-F the most advantageous 3D Co3O4 catalyst for OX activation to degrade SFA. The mechanism of SFA by this 3D Co3O4/OX is also investigated and the corresponding SFA degradation pathway has been elucidated. The catalytic activities of Co3O4 catalysts can be correlated to physical and chemical properties which were associated with particular morphologies to provide insights into design of 3D Co3O4-based catalysts for OX-based technology to degrade emerging contaminants, such as SFA.
    Matched MeSH terms: Sulfuric Acids
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