37 research outputs found
Kajian terhadap hidrogel berasaskan selulosa bakteria (BC) dan kesan penggabungannya dengan nanopartikel perak sebagai agen antibakteria
This research investigated the ability of bacterial cellulose (BC) based hydrogel incorporated with silver nanoparticles as
antibacterial agent. Free radical polymerization has been used to synthesize the BC hydrogel. The silver nanoparticles was
integrated and reduced using sodium boron hydrate as the reducing agent. The swelling capability of the hydrogel at different
pH was also examined. The FTIR results showed that acrylic acid (AA) was successfully grafted to the bacterial cellulose
networks. Other analyses such as swelling tests, antibacterial, Differential Scanning Calorimetry (DSC), X-ray Diffraction
(XRD) and Scanning Electron Microscope (SEM) were also carried out to the hydrogel sample. The antibacterial tests found
that hydrogel incorporated with silver nanoparticles was able to inhibit the bacterial growth
Sintesis dan sifat termal natrium kanji sulfat Dioscorea pentaphylla
Kanji Dioscorea pentaphylla telah diubah suai dengan pensulfatan dan peneutralan bagi menghasilkan natrium kanji sulfat. Tindak balas pensulfatan dilakukan dengan asid sulfurik dalam etanol dan air pada suhu 0oC. Darjah penukargantian dikira berdasarkan peratus karbon dan sulfur yang ditentukan menggunakan penganalisis unsur CHNS. Natrium kanji sulfat yang mempunyai darjah penukargantian dan peratus nisbah berat hasil yang tinggi dipilih dan dicirikan dengan spektrum transformasi Fourier inframerah (FT-IR) dan profil pembelauan sinar-X (XRD). Kehadiran dua puncak getaran regangan C-O-S dan S=O dalam spektrum FT-IR dan puncak berbeza yang terhasil dalam corak difraktogram XRD membuktikan tindak balas berlaku pada struktur kanji. Sifat termal juga ditentukan dengan kalorimeter pengimbas pembezaan (DSC) dan analisis termogravimetri (TGA). Natrium kanji sulfat yang dihasilkan mempunyai kestabilan termal yang baik kerana mempunyai suhu penguraian pada 265oC. Natrium kanji sulfat ini sesuai dijadikan bahan tambahan dalam penghasilan hidrogel, organogel dan filem dengan sifat anionik kerana degradasi tidak terjadi di bawah suhu ini
Cellulose-based hydrogel as halal agricultural medium
Waste paper has been thrown away and caused environmentally problem. Preparation of cellulose-based hydrogel from waste
paper has been developed to decrease the pollution since waste paper contains more than 60% of cellulose. Cellulose-based
hydrogel is produced from the waste paper solution. To make into hydrogel, the addition of crosslinking agent is needed
since hydrogel is defined as a 3D network structure that is crosslinked either chemically or physically. In this study, the
waste paper will be treated first to remove impurities. Sodium hydroxide/urea (NaOH/Urea) has been used as a solvent for
waste paper dissolution. As hydrogel needed crosslinking to remain the network structure, we used citric acid (CA) as a
chemical crosslinking agent and the heating at 60°C and 70°C before and after swelling was studied. The aim of this study is
to produce halal soilless agricultural medium using cellulose-based hydrogel media from the waste paper by using non-toxic
and environmental friendly solvents and CA as crosslinking agent. Waste paper hydrogel will be characterized via swelling
ratio where the highest swelling is about 19% at 70°C heating temperature. Fourier-transform infrared (FTIR) shows a broad
band of OH at 3339 cm-1 and another band was shown at 3432 cm-1 for 70°C heating temperature represent OH from the
solvent
A Study on Microgel System as a Template for Dispersion and Separation of Chiral Tartaric Acid
Separation of tartaric acid enantiomers in organic compounds using conventional techniques requires high energy demand, high chemicals consumption, lengthy, complicated and expensive processes. This research demonstrates utilization of PNIPAM microgel system as a template for incorporation of chiral D- and L- tartaric acids (TA). The poly(n-isopropylacrylamide) (PNIPAM) microgel was synthesized using surfactant free emulsion polymerization (SFEP) and was characterized using standard procedures. The combination of 1.4×10-3 g/ml microgel with 3.02×10-4 g/ml TA gave the most stable system. Subsequently, a two-phase system was obtained after centrifugation. Both phases were subjected to dynamic light scattering (DLS) analysis and the corresponding separated systems gave particle sizes ranging from 80-90 nm for the upper phase, and 1200-1500 nm for the lower phase. Scanning electron micrographs showed the presence of agglomeration in the lower phase, supporting the DLS results. Nuclear magnetic resonance (1H NMR) analysis confirmed the presence of TA indicated by a peak at δ = 13.1 ppm. Based on these findings, the system can be a potential alternative template for TA racemix acid dispersion and separation
The effect of temperature on the dispersion of α-Mangostin in PNIPAM microgel system / Madihah Ahmad, Bohari M. Yamin and Azwan Mat Lazim
α-Mangostin was extracted from the pericarp of the Malaysian local Garcinia mangostana linn., The structure was characterised by Infrared red, UV-Visible and Nuclear
Magnetic Resonance spectroscopic data. The fluorescence peak at 500nm in ethanol was not observed in PNIPAM microgel solution. The increase of colloidal size of the gel in the presence of α-mangostin was studied by Dynamic Light Scattering and Transmission Electron Microscope. The size of the particle also increases with increasing temperature up to 45⁰C after which it began to shrink. The TEM micrograph at 45°C showed a uniformly structured pattern of the gel occurs in the range of the lowest solution critical temperatur
Kebolehserapan metilena biru oleh hidrogel selulosa bakteria teradiasi gamma menggunakan isoterma langmuir dan freundlich
Kajian ini bertujuan menghasilkan hidrogel responsif berasaskan selulosa bakteria yang diperoleh daripada Nata de
Coco (NDC) dan asid akrilik (AA). Tiga jenis sampel telah disediakan berdasarkan nisbah NDC:AA iaitu sampel hidrogel
A [1:1], B [2:1] dan C [3:1]. Pencangkukan AA terhadap molekul NDC menggunakan kaedah pempolimeran radikal
Gamma (GRP) menghasilkan hidrogel NDC-AA (sumber: 60Co). Kaedah yang menggunakan tenaga yang tinggi ini akan
menghasilkan radikal bebas seperti OH•, H•, H2O2 dan H2. Kesemua radikal ini menyerang kumpulan berfungsi yang
terdapat pada NDC dan AA seterusnya menggalakkan proses pencangkukan AA terhadap NDC. Hidrogel B [2:1] dipilih dan
diuji sebagai penjerap metilena biru (MB) dan perubahan keamatannya telah dianalisis menggunakan spektrofotometer
UV-VIS. Keputusan yang diperoleh telah diselaraskan dengan dua model isoterma, Langmuir dan Freundlich. Perbandingan
pemalar bagi kedua-dua model isoterma ini mendapati hidrogel B [2:1] yang dihasilkan telah mematuhi kedua-dua
model isoterma. Keputusan yang diperoleh ini menyokong keupayaan hidrogel B [2:1] untuk digunakan sebagai penjerap
alternatif MB yang paling efisien
Empty fruit bunch cellulose based sorbent for oil sorption in palm oil mill effluent
The aim of this study was to develope hydrophobic biodegradable cellulosic sorbent materials from empty fruit
bunch (EFB) for oil sorption in palm oil mill effluent (POME). EFB cellulose was modified using acetic anhydride (AA)
and the effect of ratio of EFB cellulose mass to AA volume (1:20, 1:30, 1:40, 1:50 g/mL) at 3 h reaction time with 5%
(w/v) pyridine catalyst. The acetylation process was quantitatively determined using the weight percent gain (WPG)
and modified EFB cellulose (1:40) showed the highest WPG (13.0%) compared to the other ratios. Fourier Transform
Infrared (FTIR) spectrum shows that after the modification, the intensity of –OH peak at 3329 cm-1 decreased and
the new peak at 1728 cm-1 of C=O ester emerged. This implied that acetylation process was successful when AA
volume increased except for 1:50 ratio. Sample 1:40 also showed good hydrophobicity characteristic with the degree
of hydrophobicity (DH) of 87.7%. X-ray diffraction (XRD) analysis shows that crystallinity index for 1:40 is the lowest
which indicated that the sample become amorphous due to acetylation. The result is in agreement with scanning
electron microscope (SEM) micrograph that shows the surface morphogy of EFB cellulose after the modification
became rougher. Moreover, the modified EFB cellulose 1:40 was able to absorb oil from POME up to 98.5%. Thus, it is
proven that cellulose from EFB can be modified to a certain ratio to make it an extremely promising natural source
oil sorbent in treating POME
The optimization of heating temperature for carbon extraction from peat soil
This study aims to find the optimised heating temperature for carbon extraction from
peat soil. Ccarbon from peat soil was extracted by the pyrolisation process at temperature, T =
200, 300, 400, 500, 600 and 700°C for 5 hours. The carbon, C and silica, Si content extracted
from peat soil at various heating temperatures were measured by using an Energy Dispersive
X-Ray analyzer (EDX) at 3 points on the sample surface. High atomic percentage of carbon
(95.44 %) was measured at T = 400°C, while the highest atomic percentage of silicon was
recorded at T = 700°C (30.79 %). The surface morphology of peat soil was analysed using
Scanning Electron Microscope (SEM) at 800 magnifying power, and it was clearly seen that
peat fragments were pyrolised at high heating temperature with pores enhancement. The
molecular structure parameter of the extracted carbon were identified using Laser Raman
analysis. The peak positions of D-band and G-band for raw peat soil were observed at Raman
shift of 1379.62 and 1549.02 cm-1, respectively. Meanwhile, the D-band for peat soil heated at
temperature of 400°C was 1391.56 cm-1 whereas the G-band has peak position at 1562.16 cm-1
.
From the Raman spectra of the optimum heating temperature at 400°C, it was revealed that the
carbon molecular structure from the peat soil is mainly attributed by graphite and diamond
structure
Dimethyl Sulfoxide-Treated Starch of Dioescorea hispida as a Green Corrosion Inhibitor for Low Carbon Steel in Sodium Chloride Medium
This research was focused on discovering the utilization of Dioscorea hispida (gadong tuber) starch as a potential green corrosion inhibitor for SAE 1045 carbon steel in 0.6 M NaCl media. Raw starch from gadong tubers was obtained through the extraction and precipitation process prior to drying in producing fresh starch powder. The insoluble starch powder was then dissolved in 90% dimethyl sulfoxide (DMSO) solvent and was ready for corrosion inhibitor testing. The extraction of starch powder was analyzed using Fourier Transform Infrared Spectroscopy (FTIR) to identify the presence of functional groups that may contribute to the inhibition of the carbon steel sample. The inhibitive performance of gadong tuber starch (GTS) as a green corrosion inhibitor was studied by weight loss measurement and potentiodynamic polarization in a corrosive medium using 0.6 M sodium chloride (NaCl) solution. Effect of GTS concentration on corrosion behavior was investigated. Based on the findings, 1500 ppm of GTS demonstrated the highest corrosion inhibition performance as the corrosion rate of carbon steel immersed in plain 0.6 M NaCl was reduced from 0.131 to 0.018 mm/year, which is up to 86.3 IE% of inhibition efficiency in the presence of the green corrosion inhibitor. According to potentiodynamic polarization analysis, corrosion current density (Icorr) was also decreased from 1.13 × 10−5 to 1.55 × 10−6 mA/cm−2
Penghasilan zarah nano ferum oksida (FeNPs) daripada garam ferosenium menggunakan hidrogel poli-akril amida (P(Am) sebagai templat
Kajian ini adalah bertujuan mengkaji potensi hidrogel sebagai templat nanoreaktor bagi menghasilkan zarah nano ferum oksida (FeNps). Hidrogel Poli-AkrilAmida (PAAm) telah dihasilkan dengan menggunakan kaedah pempolimeran radikal bebas. Keupayaan penyerapan air dalam hidrogel telah diuji dan nisbah pembengkakan tertinggi telah berlaku pada larutan penimbal pH10. Hidrogel yang terhasil telah dicirikan dengan menggunakan pengimbas mikroskop elektron (SEM) diikuti dengan spektroskopi serakan tenaga X-ray (SEM-EDEX) untuk menentukan jumlah peratusan ferum (Fe). Selepas proses pengkalsinan, zarah nano diekstrak daripada hidrogel PAAm dan seterusnya dianalisis menggunakan mikroskop transmisi elektron (TEM) dan analisis pembelauan sinar-X (XRD). Hasil TEM telah menunjukkan bahawa saiz zarah yang dihasilkan adalah antara 5 - 20 nm. Analisis XRD pula mengesahkan kehadiran zarah ferum oksida (Fe2O3). Keputusan ini menunjukkan bahawa hidrogel berpotensi digunakan sebagai nanoreaktor bagi menghasilkan zarah nano