Nabilah Aminah Lutpi

Effects of changes in chemical and structural characteristic of ammonia fibre expansion (AFEX) pretreated oil palm empty fruit bunch fibre on enzymatic saccharification and fermentability for biohydrogen

Oil palm empty fruit bunch (OPEFB) fibre is widely available in Southeast Asian countries and found to have 60% (w/w) sugar components. OPEFB was pretreated using the ammonia fibre expansion (AFEX) method and characterised physically by the Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The results show that there were significant structural changes in OPEFB after the pretreatment step, and the sugar yield after enzymatic hydrolysis using a cocktail of Cellic Ctec2® and Cellic Htec2® increased from 0.15gg(-1) of OPEFB in the raw untreated OPEFB sample to 0.53gg(-1) of OPEFB in AFEX-pretreated OPEFB (i.e. almost a fourfold increase in sugar conversion), which enhances the economic value of OPEFB. A biohydrogen fermentability test of this hydrolysate was carried out using a locally isolated bacterium, Enterobacter sp. KBH6958. The biohydrogen yield after 72h of fermentation was 1.68mol H2 per mol sugar. Butyrate, ethanol, and acetate were the major metabolites.

Physicochemical characteristics of attached biofilm on granular activated carbon for thermophilic biohydrogen production

In this study, thermophilic biohydrogen production by a mixed culture, obtained from a continuous acidogenic reactor treating palm oil mill effluent, was improved by using granular activated carbon (GAC) as the support material. Batch experiments were carried out at 60 °C by feeding the anaerobic sludge bacteria with a sucrose-containing synthetic medium at an initial pH of 5.5 under anoxic conditions. The physico-chemical characteristics of the attached biofilm were evaluated after extraction of the extracellular polymeric substances (EPSs) of the biofilm using the formaldehyde–NaOH method. The main component of the biofilm was protein (60%), while the carbohydrate content accounted for 40% of the EPS. Two major absorption bands at approximately 3400 cm−1 and 1650 cm−1, characteristics of the stretching vibrations of hydroxyl and amino groups, respectively, were identified in the FT-IR spectra, confirming the composition of the EPS. Observations using scanning electron microscopy (SEM) illustrated the attachment of rod-shaped bacterial cells on the GAC at 60 °C. A maximum hydrogen production rate of 4.3 mmol L−1 h−1 and a hydrogen yield of 5.6 mol H2 per mol sucrose were obtained from this attached biofilm system. The major soluble metabolites of fermentation were acetic acid and butyric acid. The results showed that the granular activated carbon enhanced the biohydrogen production by stabilizing the pH and microbial metabolites and therefore could be used as a support material for fermentative hydrogen production under thermophilic conditions on a large scale.

Investigation of Noise Reduction Coefficient of Organic Material as Indoor Noise Reduction Panel

Noise can cause a few types of effect to human health especially in hearing like hearing loss. Indoor noise pollution comes from many sources and places. The research focuses on the sound reduction wall surface material rather than any techniques available and using organic material like coconut coir fiber, rice husk and sawdust. These sound reduction material is suitable to apply as interior lining for homes and offices. This research conducted to compare the efficiency of coconut coir fiber, rice husk and sawdust as indoor noise reduction, to evaluate the effectiveness indoor noise level by using wall surface sound reducer material and to determine the best material that will reduce noise level. In preparation of board panel, two binders were used which is polyester resin and hardening catalyst, cement and sand. For board panel using binder of polyester resin and hardening catalyst, the binders were stirred for two minutes. Then, the mixture of polyester resin, hardening catalyst with raw material was mix uniformly. The suppression done for 24 hours in order to obtain a composite outcome that is denser. Then, the ratio for coconut coir fiber, cement and sand is 1.5:0.5:0.5, the same ratio used for sawdust and rice husk and the Noise Reduction Coefficient (NRC) will be determined. The parameter use to determine the NRC and the sound transmission are the frequency, speaker intensity and the distance from the speaker. If not absorbed, the sound can be reflected and this will prevent sound dispersed to other space. The results show rice husk is better with cement binder and sand, while for polyester resin and hardening catalyst binder, sawdust is the best. Therefore, currently organic materials present good alternative to synthetic material providing good health with green environment as well as enhancing natural agricultural and growth.

Reduction of Rejection Rate for High Gloss Plastics Product Using Six Sigma Method

High gloss plastics part in injection molding industries were widely used in Malaysia. However the high rejection rate in this industries were major problem affecting the economic aspects. Therefore this paper presents an approach of implementing six sigma method to reduce the rejection rate in a plastic injection molding process for high gloss plastics part. Define, Measure, Analyze Improve and Control (DMAIC) methodology was applied as basis of the study. By using current process, the average of rejection is 40.6% and the aim of this study is to reduce the rejection rate to less than 10 % . All potential factors were taken into account to identify the significant factors. The improvement process was made base on the analysis output. This study was successful with increment in sigma level from 1.74 σ to 3.00 σ. .

Sorption of Methylene Blue and Acid Orange 7 onto Ananas comosus Peels and Leaves Based Activated Carbon

The adsorption of Methylene Blue (MB) and Acid Orange 7 (AO7) dye onto Ananas Comosus Mixed Peels and Leaves (ACMPL) were carried out by conducting four different parameters such as initial concentration, pH, dosage of adsorbent, and contact time. Effect of initial concentration for both dyes showed that higher initial concentration would take longer contact time to attain equilibrium due to higher amount of adsorbate molecules. The effect of pH showed highest percentage removal for MB is at pH 9 which is 95.81%. Meanwhile for AO7 the highest percentage removal is 31.06% at pH 3. The percentage removal of MB had reached the equilibrium at dosage 0.5g while AO7 keep increasing with the increment of adsorbent dosage. The percentage removal of MB and AO7 had increased until hour 2.5 which was from 72.5% to 86.93% and 19.441% to 36.89% respectively and reached equilibrium at 3 hour contact time.

A Study of Fire Retardant Effect in Natural Fiber Composite Panels with Magnesium Hydroxide and Zinc Borate as Additives

The objective of this study is to investigate the fire retardancy effect of coconut coir, rice husk and sawdust panels which are incorporated with magnesium hydroxide (Mg (OH)2) and zinc borate (2ZnO∙3B2O3∙3.5H2O) as additives. The natural fiber and additives are mixed and cured for one week, with polyester resin and hardening catalyst as binders. Fire retardancy of these panels are tested according to American Society for Testing and Materials (ASTM) Horizontal (D 365) and Vertical Burning (D 3801) tests. Principle of fire retardants and mechanism of polymer combustion are shown in this study too. The study revealed that the sawdust panels with both additives have the highest fire retardancy compared to rice husk and coconut coir panel with both additives.

Adsorption Efficiency of Garcinia mangostana Linn. (GML) Shells Based Activated Carbon

The objective of this study is to investigate the adsorption efficiency of Garcinia Mangostana Linn. (GML) shells based activated carbon using two synthetic dyes which are methylene blue and acid orange 7. The parameters which were studied in batch mode are the effect of contact time, initial dyes concentration, particle size, adsorbent dosage and temperature. Scanning Electron Microscope (SEM) was used to determine the physical characterization of GML. Base on the percentage removal results, the basic dye (Methylene blue) depicts better performance if compared to the acid dye (Acid orange 7) with approximately 90% of the best percentage removal of Methylene blue.