Papers by Othman Sulaiman
Water
Water treatment using activated carbon is widely accepted, despite its high production cost. Ther... more Water treatment using activated carbon is widely accepted, despite its high production cost. Therefore, this study was aimed to investigate the potential of cassava stem in activated carbon form for methylene blue (MB) dye uptake from water. Raw cassava stem (RCS) was also utilized to evaluate the difference between cassava stem in its raw form and after being converted to the activated carbon (ACS). The MB adsorption from water using the RCS and ACS was done in this study. The batch adsorption study showed fast MB uptake by ACS at 60 min contact time, while higher adsorbent dosage and higher pH contributed to higher adsorption percentage. The thermodynamic study showed positive values of ∆H° of ACS, indicating that the adsorption process of MB was endothermic. Meanwhile, the negative value of ∆G° showed that the adsorption processes of MB were spontaneous. The thermodynamic study showed higher fitting to Langmuir isotherm, with data from the kinetic study showing better pseudo-seco...
Cellulose Chemistry and Technology
Oil palm trees older than 25 years of age are usually cut down because of low productivity and th... more Oil palm trees older than 25 years of age are usually cut down because of low productivity and the resulting biomass is left to degrade naturally. Unfortunately, the disposal of this biomass becomes a major issue in many plantations, as it requires additional costs. Considering the high starch content of oil palm trunks, it is essential to find a potential utilisation for this biomass. The main objective of this study was to evaluate some of the properties of experimentally manufactured particleboard panels made from rubberwood (Hevea brasiliensis) using oil palm starch as a binder. The starch extracted from oil palm trunk was esterified using citric acid before being used as an organic-based wood binder. Three types of panels, namely, one bound with citric acid modified oil palm starch (CAMOPS), another using a combination of citric acid modified oil palm starch and 2% urea formaldehyde (CAMOPSUF), and finally, the third glued with urea formaldehyde resin (control), were manufactured in the study. Panels of 210 mm x 210 mm x 50 mm dimensions were made at three target density levels. The results showed that the thickness swelling of CAMOPSUF wood composites improved up to 79.37%. Furthermore, at 0.70 gcm-3 density level, all the wood composites met the mechanical strength standard, as proposed by the Japanese Industrial Standards. The wood composite prepared using modified oil palm starch binder has high potential to be commercialized, besides offering a way to improve waste disposal management on oil palm plantations.
Chemistry Central journal, Jan 12, 2018
A series of novel 4-thiazolidinone inhibitors SKYa-SKYg, containing coumarin as a core structure ... more A series of novel 4-thiazolidinone inhibitors SKYa-SKYg, containing coumarin as a core structure were synthesized via facile and efficient method. The structures of the synthesized compounds were established by extensive spectroscopic studies (FT IR, 1D NMR, 2D NMR, LC-MS) and elemental analysis. All the synthesized hybrids were further evaluated for their potential as anti-tubercular agents against Mycobacterium tuberculosis H37Rv ATCC 25618, and anti-bacterial agents against Escherichia coli, Enterobacter aerogenes, Salmonella typhi, Streptococcus pneumoniae and Staphylococcus aureus. Interestingly, the hybrids displayed potent bioactivity. However, compounds SKYc, SKYd, and SKYe appeared to be more effective against the tested bacterial strains, among which compound SKYb showed the highest inhibition against all the bacterial strains ranging from 41 to 165 μg/mL, as compared to the standards, streptomycin, kanamycin and vancomycin. Moreover, derivative SKYa was found to be the st...
Enzyme and microbial technology, 2018
Oil palm trunk (OPT) is one of the most promising lignocellulosic bioresources. To develop effect... more Oil palm trunk (OPT) is one of the most promising lignocellulosic bioresources. To develop effective biodegradation, thermophilic, anaerobic microorganisms were screened from bovine manure compost using fibrillated OPT (f-OPT) pretreated by wet disk milling as the substrate. One thermophilic, anaerobic bacterium, strain CL-2, whose 16S rDNA gene has 98.6% sequence identity with that of Caldicoprobacter faecale DSM 20678, exhibited high degradation activity (32.7% reduction in total dry solids of f-OPT). Strain CL-2 did not use cellulose as a carbon source, but used hemicelluloses such as xylan, arabinoxylan, starch and pectin at 70 °C. Phylogenetic and morphologic analyses and the polysaccharide use suggest that CL-2 may be classified as a novel species of Caldicoprobacter, named Caldicoprobacter sp. CL-2. To characterize enzymatic activities of CL-2, extracellular enzymes were prepared from culture broth using beechwood xylan as the carbon source. The extracellular enzymes showed h...
International Journal of Agricultural Research
Applied biochemistry and biotechnology, Jan 30, 2017
The availability of fermentable sugars in high concentrations in the sap of felled oil palm trunk... more The availability of fermentable sugars in high concentrations in the sap of felled oil palm trunks and the thermophilic nature of the recently isolated Bacillus coagulans strain 191 were exploited for lactic acid production under non-sterile conditions. Screening indicated that strain 191 was active toward most sugars including sucrose, which is a major component of sap. Strain 191 catalyzed a moderate conversion of sap sugars to lactic acid (53%) with a productivity of 1.56 g/L/h. Pretreatment of oil palm sap (OPS) using alkaline precipitation improved the sugar fermentability, providing a lactic acid yield of 92% and productivity of 2.64 g/L/h. To better characterize potential inhibitors in the sap, phenolic, organic, and mineral compounds were analyzed using non-treated sap and saps treated with activated charcoal and alkaline precipitation. Phthalic acid, 3,4-dimethoxybenzoic acid, aconitic acid, syringic acid, and ferulic acid were reduced in the sap after treatment. High conce...
Carbohydrate Polymers, 2016
Cellulose nanocrystals were isolated from oil palm trunk by total chlorine free method. The sampl... more Cellulose nanocrystals were isolated from oil palm trunk by total chlorine free method. The samples were either water pre-hydrolyzed or non-water pre-hydrolyzed, subjected to soda pulping, acidified and ozone bleached. Cellulose and cellulose nanocrystal (CNC) physical, chemical, thermal properties, and crystallinity index were investigated by composition analysis, scanning electron microscopy, transmission electron microscopy, fourier transform infrared, thermogravimetric analysis and X-ray diffraction. Water pre-hydrolysis reduced lignin (<0.5%) and increased holocellulose (99.6%) of ozone-bleached cellulose. Water pre-hydrolyzed cellulose exhibited surface fibrillation and peeling off after acid hydrolysis process compared to non-fibrillated of non-water pre-hydrolyzed cellulose. Water pre-hydrolysis improved final CNC crystallinity (up to 75%) compared to CNC without water pre-hydrolysis crystallinity (69%). Cellulose degradation was found to occur during ozone bleaching stage but CNC showed an increase in crystallinity after acid hydrolysis. Thus, oil palm trunk CNC can be potentially applied in pharmaceutical, food, medical and nanocomposites.
Journal of Dispersion Science and Technology, Apr 20, 2011
The reaction of the common pain reliever acetaminophen (paracetamol, 4-acetamidophenol) with dich... more The reaction of the common pain reliever acetaminophen (paracetamol, 4-acetamidophenol) with dichromate was investigated over time under conditions that simulate wastewater disinfection. The occurrence of the acetaminophen in the water bodies, especially in drinking water resources, has received considerable attentions. In situ chemical oxidation is a promising cost-effective treatment method to remove acetaminophen from water body as it degrades the drug to large extent. Experimental results indicate that the reaction is second order overall and first order with respect to both dichromate and acetaminophen, and has activation energy of 14.1 kJ/mol. The second-order rate constant ranges from 1.56 Â 10 À3 to 13.4 Â 10 À3 min À1 at temperature from 35 to 65 C. The acetaminophen degradation rates can be accelerated through increasing reaction temperature and oxidant concentration. The reaction under acid conditions was slightly faster than under alkaline or neutral conditions. Two of the products were unequivocally identified as the toxic compounds 1,4-benzoquinone and ammonium ions. These results demonstrate that acetaminophen is likely to be transformed significantly into toxic product if dichromate is used as an oxidizing agent during wastewater treatment.
The physical, anatomical and strength properties of 3-year-old cultivated tropical bamboo Giganto... more The physical, anatomical and strength properties of 3-year-old cultivated tropical bamboo Gigantochloa scortechinii was studied. Five (5) culms of the bamboo were selected and harvested from the Bambusetum plot located in the Forest Research Institute Malaysia in Kepong. The anatomical study focussed on the vascular bundles and fibres located at the internodes and nodes No. 8 at the outer, middle and inner cross section of the bamboo. The sizes of the vascular bundles length, vascular bundles width, fiber length, fiber diameter, fiber lumens diameter, fiber walls thickness and fiber Runkle's ratio were measured in relation to the samples positions at the internodes, nodes, and positions in the cross-section of the bamboo culms. The physical study gives emphasis on the moisture content, basic density and dimensional stability. The strength properties study focused on the tension parallel to the grain and shear test. Both the physical and strength study were conducted at internodes and nodes No. 8 of the bamboo.
J Chem Crystallography, 2010
Acta Crystallographica Section E: Structure Reports Online is the IUCr's highly popular open-acce... more Acta Crystallographica Section E: Structure Reports Online is the IUCr's highly popular open-access structural journal. It provides a simple and easily accessible publication mechanism for the growing number of inorganic, metal-organic and organic crystal structure determinations. The electronic submission, validation, refereeing and publication facilities of the journal ensure very rapid and high-quality publication, whilst key indicators and validation reports provide measures of structural reliability. The journal publishes over 4000 structures per year. The average publication time is less than one month. Crystallography Journals Online is available from journals.iucr.org Acta Cryst. (2011). E67, o1719-o1720 Mehdi et al. • C 25 H 30 O 5
Http Dx Doi Org 10 1080 07373937 2013 829855, Jan 24, 2014
ABSTRACT The objective of this study was to determine the isothermal drying kinetics of Acacia ma... more ABSTRACT The objective of this study was to determine the isothermal drying kinetics of Acacia mangium wood blocks by employing a relative humidity-controlled drying chamber. A model was developed based on solution of Fick's second law and evaluated through the coefficient of determination (R2 ), sum of square error (SSE), root mean square error (RMSE), and reduced chi-square (χ 2 ). This model was compared to semi-theoretical models which are commonly used to describe the drying behavior of biomass in previous studies. The porosity and shrinkage characteristics of dried specimens were also evaluated. Based on the findings in this work, it was determined that the proposed model resulted in an excellent fit with experimental data for all four drying temperature levels of 30, 35, 40, and 45∘ C to describe the isothermal drying kinetics of Acacia mangium . It appears that volumetric shrinkage of the samples decreased quadratically with decreasing moisture ratio. The activation energy of the drying process was determined to be 41.07 kJ/mol.
ABSTRACT Acacia mangium wood was chemically activated in two stage batch process using activating... more ABSTRACT Acacia mangium wood was chemically activated in two stage batch process using activating agents potassium hydroxide (KOH) and calcium oxide (CaO) in a capped silica crucible at 500ºC in the absence of any purging gases. In first stage mechanically grounded coarser sawdust of Acacia mangium was soaked in diluted solution of KOH and CaO for 24 hours at 75ºC, followed by second stage in which dried precursor material was subjected to pyrolysis at 500ºC for two hours. The extents of impregnation ratio of precursor to activating agents were fixed at 2:1(w/w). The mesopore and micropore characterization of the formed activated carbons were done by physical adsorption of N2 gas at 77 K. KOH has strong chemical interaction on the precursor material than the CaO, hence make the surface porous. The percentage yield of activated carbon was more for CaO activated samples than KOH activated samples. Surface morphology and elemental constituents of the activated carbons were done by scanning electron micrograph (SEM) and energy dispersive X-ray spectroscopy (EDX). Carbon content was found more in KOH treated samples than CaO treated samples. The surface functional groups were studied with Fourier Transform Infrared (FT-IR) spectra.
Endocrine Practice, Apr 1, 2006
Journal of Chemical Crystallography, Jan 29, 2010
Acta Crystallographica Section E: Structure Reports Online is the IUCr's highly popular open-acce... more Acta Crystallographica Section E: Structure Reports Online is the IUCr's highly popular open-access structural journal. It provides a simple and easily accessible publication mechanism for the growing number of inorganic, metal-organic and organic crystal structure determinations. The electronic submission, validation, refereeing and publication facilities of the journal ensure very rapid and high-quality publication, whilst key indicators and validation reports provide measures of structural reliability. The journal publishes over 4000 structures per year. The average publication time is less than one month. Crystallography Journals Online is available from journals.iucr.org Acta Cryst. (2011). E67, o1719-o1720 Mehdi et al. • C 25 H 30 O 5
Cultivated Bambusa vulgaris of two and four-year old were harvested and studied for their anatomy... more Cultivated Bambusa vulgaris of two and four-year old were harvested and studied for their anatomy and physical properties. The anatomy properties between the two age-group of bamboo were observed to have some degrees of variation. This showed that the bamboo anatomy structure has strong correlation with age. The frequency of vascular bundles was greater at the bottom and top portion than in the middle portion of both age-groups. There was no difference in vessel diameter between the two and four-year old culms at the middle of the culms wall thickness. The cell's wall thickness of both parenchyma and fibre were greater in the 4 year-old than in the 2 year-old culms. In the physical aspect, basic density was found to be higher in the 4 year-old culms than in the 2 year-old by 5 to 8%, and increases from lower to upper internodes showing that there is a maturing process going on between the two age-group relative to the tissue type that they possess.
Indonesian Journal of Chemistry, Jun 22, 2010
J Surfactants Deterg, 2011
The mutual separation of a mixture of cetyltrimethyl ammonium chloride (CTAC), methyl trioctyl am... more The mutual separation of a mixture of cetyltrimethyl ammonium chloride (CTAC), methyl trioctyl ammonium bromide (MTOB), dodecyltrimethyl ammonium chloride (DTAC), benzyltrimethyl ammonium chloride (BTAC) and tetrabutyl ammonium bromide (TBAB), was achieved on silica high performance thin layer chromatographic plates using dimethyl sulfoxide with aqueous sodium-L-tartrate dibasic dihydrate as the solvent system. The effect of concentration of sodium-L-tartrate dibasic dihydrate on the mobility of all the five quaternaries was examined. The limit of detection of CTAC, MTOB, DTAC, BTAC and TBAB was estimated as 0.6, 0.6, 0.3, 0.6 and 0.3 lg/zone, respectively. The method developed was utilized to identify these surfactants in different spiked water samples after their preliminary separation.
Uploads
Papers by Othman Sulaiman