Nor Helya Iman Kamaludin
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Nor Helya Iman Kamaludin
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Nor Helya Iman, Kamaludin
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Kamaludin, Nor Helya Iman
Kamaludin, N. H. I.
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Scopus Author ID
57163428800
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DVR-1806-2022

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Microbiological removal of hydrogen sulphide from natural rubber latex processing wastewater by Acidithiobacillus thiooxidans strain UniMAP-AIN01

2020 , Sandrasekaran Naresh , Nurul Ain Harmiza Abdullah , Nor Helya Iman Kamaludin , Muhd Afiq Hizami Abdullah , Mohamad Fahrurrazi Tompang

Acidithiobacillus thiooxidans is an acidophilic chemoautotrophic bacterium which capable to convert the toxic hydrogen sulphide in wastewater into non-toxic compounds. The Acidithiobacillus thiooxidans strain UniMAP-AIN01 was previously isolated from a local natural rubber latex processing mill. In this study, the A. thiooxidans strain UniMAP-AIN01 was subjected to its growth performance evaluation in the wastewater of natural rubber latex. The sulphur content in the wastewater was utilized as energy source and support their growth. It was discovered that the A. thiooxidans strain UniMAP-AIN01 has long doubling time of 2 days in thiosulphate medium, while log phase lasted until 6th day of incubation. Regression analysis of the growth kinetic was established with the aid of POLYMATH software. The precision value obtained as follows; linear regression, R2 of 0.9811, adjusted linear regression, Adj R2 of 0.9764, root mean square deviation, RMSD of 0.0015, and variance of 1.992 × 10-5 indicate the data is highly correlated and error is insignificant. Assessment on hydrogen sulphide removal efficiency using locally isolated A. thiooxidans strain UniMAP-AIN01 revealed 90% of hydrogen sulphide removal was achieved within a week.

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Cellulose nanocrystals from bleached rice straw pulp: acidic deep eutectic solvent versus sulphuric acid hydrolyses

2021-07-01 , Lim W.L. , Ahmad Anas Nagoor Gunny , Kasim F.H. , Subash Chandra Bose Gopinath , Nor Helya Iman Kamaludin , Arbain D.

The present work aims to investigate the feasibility of oxalic acid-choline chloride deep eutectic solvent (OA-ChCl DES), which serves as a promising green solvent that utilized in the acidic deep eutectic solvent (DES) hydrolysis. Oxalic acid-choline chloride DES cellulose nanocrystal (OA-ChCl DES CNC) was isolated from the bleached DES treated pulp (BP) through the acidic DES hydrolysis using 1:1 molar ratio of OA-ChCl DES. The functional groups, crystallinity index, morphological structure, particle size, zeta potential, thermal stability and surface chemistry of the OA-ChCl DES CNC were compared with the sulphuric acid cellulose nanocrystal (SA-CNC) that prepared via sulphuric acid hydrolysis. The findings revealed the presence of negatively charged carboxyl groups on OA-ChCl DES CNC surface after the acidic DES hydrolysis. The physicochemical analyses verified that the OA-ChCl DES CNC was in nano-sized range with polydispersity index (PdI) of 0.56, indicating slightly monodispersed nanoparticles. A stable OA-ChCl DES CNC colloidal suspension with zeta potential value of −52.1 ± 5.2 mV was obtained. The OA-ChCl DES CNC outweighed the SA-CNC in term of thermal stability (288 °C) despite having a slightly lower crystallinity index (76.7%). In fact, the OA-ChCl DES CNC with a yield of 55.1% was achieved through the acidic DES hydrolysis, suggesting that the OA-ChCl DES was capable of promoting efficient cleavage of strong hydrogen bonds in BP. Graphic abstract: [Figure not available: see fulltext.]

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Evaluation and Enhancement of Polylactic Acid Biodegradability in Soil by Blending with Chitosan

2023-06-01 , Nor Helya Iman Kamaludin , Ismail H. , Rusli A. , Sam Sung Ting , Hakimah Osman

This study highlights the soil burial degradation of polylactic acid/chitosan (PLA/Cs) biocomposites prepared by the melt compounding technique. The effect of various Cs loadings (2.5, 5, 7.5, 10 parts per hundred parts of polymer (php)) and soil burial periods (0, 2, 6, 12 months) on visual observation, weight loss, changes in functional groups, as well as tensile, thermal, and morphological properties were analyzed. The PLA/Cs biocomposites became brittle and showed more fragmentation with increasing Cs content and buried time. The result correlates with a remarkable increase in weight loss percentage of about ~ 192%, with Cs addition from 2.5 to 10 php at the end of soil degradation. Besides, a decrement in peak intensity at 1751 cm−1 and 1087 − 1027 cm−1 after 12 months signifies the breakdown of PLA ester bonds due to the hydrolytic degradation. This correlates to a significant drop of 60% and 55% in tensile strength and elongation at break, respectively, in the 2.5 php sample, whilst further Cs addition resulted in the broken of the biocomposites at the end of the soil degradation. Yet, no significant difference was observed in the tensile modulus. A consistent stiffness in the biocomposite suggests the degradation occurs in the amorphous region and leaves the crystalline part. This is proven by the 70% increment in crystallinity degree in all samples after 12 months of soil burial. Moreover, surface morphology showed numerous and extended crack formations. It proposes a notable deterioration effect of the biocomposite due to biodegradation. The hydrophilicity of Cs enhances water-polymer interaction, thereby accelerating the biodegradation of polymer components. Therefore, Cs could be a good candidate for facilitating PLA biodegradation in the natural soil environment.

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Processing, tensile and morphological characteristics of polylactic acid/ Chitosan biocomposites prepared by melt compounding technique

2020-09-21 , Nor Helya Iman Kamaludin , Ismail H. , Rusli A. , Ahmad Anas Nagoor Gunny , Sam Sung Ting

Biodegradable polymers of polylactic acid (PLA) and chitosan (Cs) has a great potential as alternative candidates to replace conventional synthetic plastic apart to reduce the plastic waste pollution due to the unique properties of superior mechanical strength, feasible processability and rapid degradation. In this work, PLA/Cs biocomposites were prepared via melt compounding and compression moulding techniques in the absence of any plasticizer and additive. The effect of chitosan loading (2.5, 5, 7.5, 10 php) on processing, tensile and morphological characteristics of PLA/Cs were evaluated using internal mixer, universal testing machine and field emission scanning electron microscopy (FESEM), respectively. Processing characteristic indicates PLA/Cs biocomposites demonstrated higher processing torque in comparison to neat PLA due to the increase in melt viscosity and decrease in chain mobility of the polymeric materials. Tensile test results revealed that the maximum strength (54.60 ± 0.51 MPa) and tensile elastic modulus (2.67 ± 0.01 GPa) was attained by PLA/2.5Cs biocomposite. In fact, the addition of chitosan content up to 10 php results in significant decreased in tensile strength and elongation at break of 23.38 ± 0.37 MPa and 0.96 ± 0.04 %, respectively. This is supported by the electron micrograph observation of the PLA/2.5Cs tensile fractured surfaces that exhibits uniform dispersion and good interfacial adhesion between chitosan and PLA matrix which signifies higher tensile properties. However, more agglomeration and poor filler-matrix interaction was observed with further addition of chitosan content of above 7.5 php which implies deterioration in tensile properties. The results suggest that the incorporation of low chitosan loading improve the processing, tensile and polymer compatibility in PLA/Cs biocomposites.

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