Norzita Ngadi

Isolation, characterization, and application of nanocellulose from oil palm empty fruit bunch fiber as nanocomposites

Nanocomposites, consisting of a polymeric matrix and nanosized elements as reinforcement, have attracted significant scientific attention because of their high mechanical performance. A large variety of nanocomposites have been prepared using bio-based materials as a matrix and nanoreinforcement, so that it can reduce the dependence on nondegradable products and move to a sustainable materials basis. The objective of this study was to isolate nanocellulose from empty fruit bunch (EFB) fiber and their reinforcing effect on polyvinyl alcohol (PVA)/starch blend films. A series of PVA/starch films with different content of nanocellulose were prepared by solution casting method. Nanocellulose fiber with diameters ranging from 4 to 15nm has been successfully prepared. On the other hand, PVA/starch films reinforced with nanocellulose fiber possess significantly improved properties compared to unreinforced film. From the results, PVA/starch films with the addition of 5% (v/v) of nanocellulose exhibited best combination of properties. This nanocomposite was found to have tensile strength at about 5.694 MPa and elongation at break was 481.85%. In addition to good mechanical properties, this nanocomposite has good water resistance and biodegradability.

Swelling behaviour and controlled drug release from cross-linked -carrageenan/nacmc hydrogel by diffusion mechanism

We studied a model system of controlled drug release using beta-carotene and κ-carrageenan/NaCMC hydrogel as a drug and a device, respectively. Different concentrations of genipin were added to crosslink the beta-carotene loaded beads by using the dripping method. Results have shown that the cross-linked beads possess lower swelling ability in all pH conditions (pH 1.2 and 7.4), and swelling ratio decreases with increasing genipin concentration. Microstructure study shows that cross-linking has enhanced the stability and structure of the beads network. Determination of diffusion coefficient for the release of encapsulated beta-carotene indicates less diffusivity when beads are cross-linked. Swelling models using adaptive neuro fuzzy show that using genipin as a cross-linker in the kC/NaCMC hydrogels affects the transport mechanism. The model shows very good agreement with the experimental data that indicates that applying ANFIS modelling is an accurate, rapid and simple way to model in such a case for controlled release applications.

Optimization of lignin production from empty fruit bunch via liquefaction with ionic liquid

The production of lignin from empty fruit bunch (EFB) has been carried out using liquefaction method with 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid (IL), in presence of sulfuric acid (H2SO4) as a catalyst. Response surface methodology (RSM) based on a factorial Central Composite Design (CCD) was employed to identify the optimum condition for lignin yield. The result indicated that the second order model was adequate for all the independent variables on the response with R(2)=0.8609. The optimum temperature, time, ionic liquid to EFB ratio, and catalyst concentration were 150.5 °C, 151 min, 3:1 wt/wt and 4.73 wt%, respectively for lignin yield=26.6%. The presence of lignin liquefied product was confirmed by UV-Vis and FTIR analysis. It was also demonstrated lignin extraction from lignocellulosic using recycled IL gave sufficient performance.

Study on Dissolution of Low Density Polyethylene (LDPE)

The world is currently facing the problem brought by plastic waste, as well as energy crisis. It is known that catalytic cracking of low density polyethylene (LDPE) waste can produce liquid fuels with similar properties to fossil fuels, hence serve as a solution to the problems mentioned. However, the problem of pipelines clogging by molten plastic feed during the cracking process has to be solved before the process can be up-scaled to continuous process. It was proposed that LDPE waste can be dissolved in suitable solvent before being catalytically cracked under suitable conditions. This study was done to investigate the behavior of virgin LDPE (in powder form) dissolved in several chosen solvents, namely benzene, toluene, chlorobenzene, isooctane, xylene and trichloroethylene, and compare the result with previous work. From the study, it was observed that LDPE samples could dissolve in benzene and toluene to a high extent. On the other hand, isooctane acted as a weak solvent towards LDPE powder. The difference of LDPE solubility in solvents was attributed to the surface area per unit mass of LDPE samples. Despite the superior property of benzene as solvent for LDPE, the safety factor study showed that toluene, xylene and trichloroethylene were more suitable to be used in LDPE dissolution. However, care should be taken to minimize possible effects of the solvents towards the body while using the solvents mentioned.

Performance of Waste Cooking Oil in Asphalt Binder Modification

Oxidation, hydrolysis and polymerization process during frying activity has caused the alteration value of the waste cooking oil (WCO) properties which is acid value and water content. This parameter is recognized as the quality measurement of waste cooking oil that might be affecting the performance of WCO in binder modification. Therefore, the aim of this paper is to relate the quality of WCO by the determination of the WCO parameter with the performance of WCO in modified binder by physical and rheological binder testing. Based on the finding, the high and good quality of WCO is recorded in December sample with the lowest acid value (1.66 mL/g) and water content (0.01 ml). The high quality of WCO affected the good performance of rheological properties where the higher rutting resistance and temperature failure at 64 °C is achieved by the modified asphalt binder with the addition of WCO in December sample.

The Effect of Coolant Temperature and Stirrer Speed for Concentration of Sugarcane via Progressive Freeze Concentration Process

Progressive freeze concentration system engaging an anti-supercooling holes crystalliser was used to concentrate sugarcane juice in order to increase its sugar content and achieve highly concentrated sugarcane juice without initial supercooling or ice lining process. The other function of this process is to retain the aromatic compound, quality and avoid operating pressure compared to using another separation process like evaporation and reverse osmosis. The process was conducted with a specific process condition including coolant temperature, stirrer speed, constant initial concentration and process time. The parameter of coolant temperature and stirrer speed was in the range of -6 to -14 °C and 150 to 350 rpm, meanwhile the constant process time was set at 180 min and constant initial concentration at 12 - 13 % Brix. The effects of coolant temperature at stirrer speed were evaluated and observed based on the value of effective partition constant, Kvalue, and concentration efficiency of the sugarcane juice. This system achieved its best performance at intermediate coolant temperature which is -8 °C and stirrer speed of 300 rpm, referring to the best K value and concentration efficiency with the values of 0.438 and 51.15 %. The heat transfer analysis was done by determination of overall heat transfer coefficient, where the highest overall heat transfer coefficient, Uo was found at coolant temperature of -8 °C and stirrer speed of 350 rpm, implying that the smallest thickness of ice was formed on the wall of the crystalliser at this condition, which favours the heat transfer in the process.

Chemical Identification of Waste Cooking Oil as Additive in Bitumen

The behavior and performance of waste cooking oil (WCO) as an additive and replacement of neat bitumen through the modification of asphalt binder is influenced by its chemical structure and composition. Therefore, the identification of chemical composition inside the WCO-modified bitumen should be identified before any modification is taken that later on will affect its performance. Thus, this paper has emphasized and explained about the chemical composition inside modified bitumen by using WCO. The characterization of each chemical element and functional group of WCO-modified bitumen are conducted by using Gas Chromatography-Mass Selective (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR). GCMS result showed that the presence of Free Fatty Acid (FFA) in WCO while from the FTIR observation, there are same type of functional group existed in all sample which is C-H bond (alkyl). Through the chemical observation conducted, therefore the chemical alteration is required to improve the performance of WCO in modified bitumen in the future.

Chemically treated chicken bone waste as an efficient adsorbent for removal of acetaminophen

Present of pharmaceutical as the emerging pollutants arise the concerns of environment community regarding the potential impact of acetaminophen (ACT) on ecological and human health. Adsorption process has been proven as an effective treatment being activated carbon as the adsorbent to remove many types of pollutant including low concentration of pollutants. However, on large scale industrial processes, utilisation of activated carbon is limited because of their high production cost. Synthesis of waste materials as a precursor of adsorbent is an attractive approach in sustainable management and economic availability. In this study, the removal of ACT from aqueous solution by chemically treated chicken bone (AC) waste was investigated. The adsorption process was conducted in a batch adsorption and affected by several experimental parameters including contact time, pH, adsorbent dose, initial concentration and temperature. With AC dosage of 0.1 g about 93 % of 1,000 mg/L ACT was removed from the aqueous solution that had pH of 2 and temperature of 25 °C. Kinetic of ACT adsorption was well described by pseudo-second order kinetic model. Meanwhile, effect of initial concentration of acetaminophen adsorption data was fitted well with Freundlich isotherm model with an R2 of 0.9909. Finally, the data obtained from effect of temperature was used to determine the adsorption thermodynamic including the enthalpy, ΔH, Gibbs energy, ΔG and entropy, ΔS. It was found that the ΔG was negative at all temperature while both, ΔH and ΔS was also negative between temperatures of 25 °C to 70 °C indicating the process of ACT adsorption was exothermic reaction and the adsorption reaction is spontaneous at low temperature.

Pyrolysis of low density polyethylene waste in subcritical water optimized by response surface methodology

Pyrolysis of low density polyethylene (LDPE) waste from local waste separation company in subcritical water was conducted to investigate the effect of reaction time, temperature, as well as the mass ratio of water to polymer on the liquid yield. The data obtained from the study were used to optimize the liquid yield using response surface methodology. The range of reaction temperature used was 162–338°C, while the reaction time ranged from 37 min to 143 min, and the ratio of water to polymer ranged from 1.9 to 7.1. It was found that pyrolysis of LDPE waste in subcritical water produced hydrogen, methane, carbon monoxide and carbon dioxide, while the liquid product contained alkanes and alkenes with 10–50 carbons atoms, as well as heptadecanone, dichloroacetic acid and heptadecyl ester. The optimized conditions were 152.3°C, reaction time of 1.2 min and ratio of water solution to polymer of 32.7, with the optimum liquid yield of 13.6 wt% and gases yield of 2.6 wt%.

Adsorptive Removal of Chromium (VI) Ions Using Cryogel Derived from Oil Palm Fronds’ Lignin

Nowadays, lignin is of special interest since it is the second most abundant biopolymer after cellulose. Given its extremely low cost and phenolic nature, lignin had become one of the leading candidates for preparing aerogels. However, production cost of carbon aerogels are considerably high due to extremely expensive supercritical drying method employed. Thus, carbon cryogels has been introduced by replacing the supercritical drying with freeze drying technique. In this study, lignin was extracted from dried and grinded oil palm fronds to be used as precursor for sol-gel polycondensation. Cryogel derived from oil palm fronds (OPF) was investigated as a suitable adsorbent for the removal of metal ions especially chromium (VI) through adsorption process. In addition, the adsorption amount was greatly increased when this cryogel was prepared with addition of ultrasonic effect instead of normal heating during the sol-gel polycondensation process. This new cryogel seems to be very promising for cost-effective treatment of heavy metals removal since the preparation is easy and being derived from a widely available and low-cost biomass feedstock.