Bifunctional Materials for CO₂ Adsorption: Short Review

In recent years, there has been growing interest in adsorbents with high surface area, high porosity, high stability and high selectivity for CO2 adsorption. By the incorporation of the additive on the supports such as zeolite, silica, and carbon, the physicochemical properties of the adsorbent and CO2 adsorption performance can be enhanced. In this review, we focus on the overview of bifunctional materials (BFMs) for CO2 adsorption. The findings of this study suggests that the high surface area and high porosity of the support provide a good medium for high dispersion and accessibility of additives (amine or metal oxide), enhancing the CO2 adsorption efficiency. The excessive additive however may lead to a decrease of CO2 adsorption performance due to pore blockage and the decrease of active sites for CO2 interactions. The synergistic relationship of the supporting material and additive is significant towards the enhancement of CO2 adsorption.

Simulation of Lovastatin Production in Solid-State Fermentation via Oil Palm Frond

Lovastatin is a potent drug for lowering the blood cholesterol. It is a competitive inhibitor of 3-hyroxy3-methyl glutaryl coenzyme A (HMG-CoA) reductase, which is a key enzyme in the cholesterol production pathway. Lovastatin increases the good cholesterol or high-density lipoproteins to prevent the formation of plaque inside the blood vessels. This study aims to develop a process model of lovastatin production, produced by Monascus purpureus under solid-state fermentation using oil palm frond. SuperPro Design V9.5 software was used to develop and simulate the process model. Three parameters which are initial moisture content, composition of peptone and potassium, were varied to investigate their effects on lovastatin production. The optimum condition simulated using the process model at pH 7 with 60% initial moisture content, 0.0075 kg/hr of potassium, and 0.0075 kg/hr of peptone was able to produce 0.0288 kg/kg of lovastatin. The simulated results show good agreement with experimental work, with low percentage error of 5.77%, and provide a good approximation on the production of lovastatin under various process operating conditions.

The Effects of Additives on the Pelletization of Raw and Torrefied Food Waste

This study evaluates the effect of various binders on the pelletization of raw and torrefied food waste (FW) towards its physical properties, including density, moisture reabsorption, and tensile strength of the formed pellets. Three binders; starch, lignin, and vegetable oil, were used to make the raw and torrefied FW pellets. It was found that the addition of lignin helps to improve the density of both, raw and torrefied FW pellets by 40% for raw FW pellets and up to 27% improvement for the torrefied FW pellets. In addition, increasing the concentration of lignin may also reduce moisture reabsorption from 48% to 40% of raw FW pellets, and the sorption was further reduced for the torrefied FW pellets. The addition of lignin improves the tensile strength, mainly the torrefied FW pellets. Results show that lignin inclusion demonstrates significant enhancement to the physical properties of FW pellets.

Synthesis of Oil Palm Frond (OPF) Based Silica Nanomaterial via Sol-gel Method with Enhanced Phenol Removal

This research investigates the potential of the oil palm frond (OPF), a well-known biomass from the oil palm industry, as a feasible silica precursor that can be utilised in the removal of phenol from an aqueous solution. Dried OPF was combusted to obtain OPF ash that was treated with citric acid before being synthesised as silica nanomaterial via the sol-gel method. The FTIR results of synthesised silica exhibit a similar peak with commercially available silica. Silica material was then used for phenol removal under different parameters including pH, contact time, dosage, concentration, and temperature, then analysed using UV-Vis Spectrophotometer. The optimum condition was obtained at pH 7 within 45 mins of contact time using 0.2 g/L silica dosage under 10 ppm of phenol concentration at 303 K that aid in enhancing phenol removal by the OPF-based silica. At this condition, silica nanomaterial successfully removed up to 68% of phenol in an aqueous solution with adsorption capacity of the adsorbent is within the range of 34 mg/g. These results demonstrate the potential application of silica nanomaterial from OPF as an adsorbent in phenol removal from wastewater.

Formulation of Plant Nutrient with Synbiotic Enhancement

Oleochemical wastewater discharge from the industry into water sources is one of the main causes of water pollution. A proper treatment is required before the effluent is discharged to the environment. Since the oleochemical wastewater contains nutrients and probiotics that are good for plants, it could be used as a nutrient provider for the plants instead. Therefore, the formulation of synbiotic plant nutrients from this effluent is an effective way of using the oleochemical effluent. This study aimed to formulate the plant nutrients by using industrial wastewater, which contains the synbiotic enhancement and validating the significance of the formulated plant nutrients into three types of plants; Abelmoschus esculentus (Okra), Solanum Melongena (Brinjal), and Capsicum annuum (Chilli peppers). Synbiotic is a combination of both prebiotics and probiotics that benefit the host by stimulating the growth of a limited number of health-promoting bacteria. To formulate the plant nutrient, the wastewater was filtered using a cotton cloth before the pre-biotics solution was added. Sample A (filtered wastewater was mixed with Sample B (prebiotics solution) by different percentages, namely F1 (100%:0%), F2 (75%:25%), F3 (50%:50%), F3 (25%:75%), 0%:100% (Sample A to Sample B respectively) and lastly, 50%:50% (Sample C (unfiltered wastewater) to Sample B respectively). The height of the plant and the number of leaves are measured weekly for four months. From the data, it can be seen that F3 gave significant results for the okra plant, in which it gains the highest height of plant compared to the other two plants. On the other hand, F6 give the best results for both the brinjal and the chilli plant where their leaves grow the highest from the second until the fourth month of plant growth. Hence, this research gives an added value to the wastewater, whereas the wastewater is used as the synbiotic plant nutrient enhancer and work best for the plants.

Adsorption Of Methylene Blue By Imperata Cylindrica: Reaction Optimization By Response Surface Methodology (RSM)

Imperata Cylindrica (IC) is a solid waste that is readily available throughout the year known as one of the most important weed in the world and frequently causes major disposal issues. As a result, using IC as a low-cost adsorbent is beneficial from both, economic and environmental standpoint to remove colors from wastewater of textile industry. This work studies the reaction optimization of methylene blue (MB) removal using IC by response surface methodology (RSM). The RSM experiments were designed with 4 independent variables (initial adsorbent dosage, initial pH, initial dye concentration, and initial temperature) and 1 response variable (percent removal of MB). According to the pareto figure, the initial pH demonstrated the greatest impact on the percent removal of MB. The RSM data predicted the optimum condition of MB removal up to 86.61% using IC, by utilizing adsorbent dosage of 1.458 g/L, at 42 oC, initial pH of 6.8 and MB concentration of 235 ppm. The chacterization analysis revealed the physicochemical properties of IC in the adsoprtion process.

Effects of Enzyme Loading, Incubation Time and Incubation Temperature on Sawdust Hydrolysis by Locally Produced Bacterial Xylanase

The present study aims to investigate the enzymatic hydrolysis conditions of bacterial xylanase on alternative cheaper substrate which is hardwood sawdust (SD) in order to produce reducing sugars (xylose). The bacterial xylanase was produced and secreted from the Bacillus sp. The wood industry in Malaysia has become a major source of foreign exchange across the globe for developing the countries. Therefore, more wood residues (sawdust) are produced during the logging and processing of wood. Most of the sawdust will be disposed into the landfills. In actual, the sawdust can be utilised into more valuable products such as in producing reducing sugars. Thus, previous researches have studied on xylose production from wooden sawdust using commercial xylanases, but only few with the bacterial xylanase. Therefore, a study on the best conditions of enzymatic hydrolysis in producing xylose from sawdust using bacterial xylanase is essential. Prior to the enzymatic hydrolysis, the hardwood sawdust was pre-treated by autoclave at 121°C for 20 min in order to breakdown the lignin linkage and obtain the hemicellulosic xylan (delignification). The enzymatic hydrolysis conditions such as enzyme loading, incubation time and incubation temperature were experimented by One-Factor-At-Time (OFAT) method. Based on the experiment, the fifth cycle pre-treated autoclaved sawdust showed 5.5-fold higher than the untreated sawdust. The best enzymatic hydrolysis conditions for xylose production were enzyme loading of 1.4%, incubation time of 30 min, and incubation temperature of 56.9 °C. These conditions also succeeded in producing 2.5-fold higher xylose than the one without the enzymatic hydrolysis.

Effect on Thermal Properties of Nanocellulose Fibre (NCF) Reinforced Biodegradable Polyhydroxylalkanoates (PHA) Composite

Currently, biodegradable materials like polyhydroxyalkanoates (PHA) and polylactic acid (PLA) are receiving huge attention from the both scientific and industrial sectors. However, since PHA has poor thermal properties, there is a shortfall in the exploration of PHA ability with filler. Therefore, this research aim is to investigate the thermal effect of nanocellulose fiber (NCF) fillers with PHA polymer. The first solution of PHA composite is prepared by dissolving 1g of PHA in 40mL of dichloromethane at 30°C for 10 minutes. The PHA-NCF composite solution is prepared by adding 1wt%, 2wt%, 3wt%, and 4wt% of NCF dissolved in 40 mL of dichloromethane into the PHA solution. The mixture solution is agitated at 45°C with a magnetic stirrer for 10 minutes. The mixture is poured into a petri dish. The prepared films were characterized by Differential Scanning Calorimeter (DSC), Fourier Transforms Infrared Spectroscopy, (FTIR), and Thermogravimetric Analysis (TGA). The FTIR analysis shows that all PHA/NCF composite samples contain similar functional groups when compared with the pure PHA. No significant changes on the thermal properties of the PHA composite was observed with the addition of NCF fillers. However, comparison within the PHA/NCF samples shows that the PHA with 2% of NCF has a higher melting temperature and requires the highest enthalpy of melting. Hence, the addition of 2% of NCF is selected to be the optimum amount of NCF filler addition to the PHA composite.

Mesoporous titania nanoparticles as photocatalyst for degradation of 2-chlorophenol

Mesoporous titania nanoparticles (MTN) was successfully prepared by microwave-assisted menthod. The performance of MTN was compared with degussa P25 (commercial TiO2) on photocatalytic degradation of 2-chlorophenol (2-CP). Both catalysts were characterized by XRD, FTIR, UV-Vis DRS and surface area analysis. The characterization data indicated that MTN has higher surface area and lower particle size than P25. The 2-CP was successfully degraded completely under UV light irradiation despite of having a slightly higher band-gap value compared with P25. This study demonstrated that MTN shows a good potential as a photocatalyst.

Preliminary Study on Pelletization of Oil Palm Empty Fruit Bunches (EFB)/Spent Activated Carbon (AC): Effect of Mixing and Adhesive Ratio

Non-renewable resources such as fossil fuels could be combusted for energy and electricity to human kind. The demand of fossil fuel energy had reached an exponential growth which caused disasters and catastrophic damages on the environment; thus, renewable resources should be implemented to protect the environment. One of the natural resources was biomass waste. In this study, spent activated carbon (AC) was co-pelletized with biomass waste, oil palm empty fruit bunches (EFB). The effect of EFB, AC and adhesive (tapioca) mixing ratio in the pellet was evaluate through physical and thermal properties. The raw materials were grinded and mixed together at different AC/EFB/tapioca ratio. The mixed raw materials were compressed at 130°C and 7 MPa for 10 minutes. The densified products were characterized by using Thermogravimetric Analysis (TGA). For the thermal characteristics, sample with 0% waste AC, 90% EFB and 10% starch had the highest mass loss rate (570 µg/min) followed by sample with 10% of waste AC, 60% of EFB and 30% of starch which was 420 µg/min. Besides, sample with 0% waste AC, 90% EFB and 10% had the highest burn out temperature (802.6 °C) followed by sample with 30% of waste AC, 60% of EFB and 10% of starch which was 792.85 °C. In conclusion, sample with 0% waste AC, 90% EFB and 10% starch had an easiest ignition and longest combustion period since it had the highest mass loss rate and burn out temperature.