Pusat Pengajian Kejuruteraan Kimia - Monograf

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Effect of membrane selectivity and configuration on purity and recovery of hydrogen from syngas
(2021-01-01)
Thamudoran, Mohashiniee
In this thesis, simulation of a membrane gas separation system for purification of hydrogen from syngas has been discussed. The simulation was done to study the effects of membrane selectivity, flow configuration, stage cut and feed pressure on the purity and recovery of hydrogen from syngas. In order to model the membrane, a complete mixing model was applied to study these effects. The mathematical modelling involved in the simulation was done in Mathcad and the results were analysed using the analysis of variance (ANOVA) under the Response Surface Methodology (RSM) method. In order to produce high purity hydrogen that is accepted as commercial industrial grade hydrogen, we studied two types of flow configuration models. Configuration 1 involves a carbon dioxide permeable membrane while configuration 2 model involves a hydrogen permeable membrane. As a result, it is noticed that in the first configuration, at the stage cut of 0.2, feed pressure of 5 bar and CO2/H2 selectivity of 1500, the highest purity of hydrogen at 52.24% and recovery of 59.58% at the permeate stream is achieved. Meanwhile in the retentate stream, the purity and recovery of carbon dioxide achieved is 52.21% and 55.53% respectively. The second configuration is when a hydrogen permeable membrane is applied. This configuration results in the highest possible purity of hydrogen of 100% with recovery of 32.52% and carbon dioxide purity and recovery at 27.35% and 90.42% respectively, at stage cut of 0.2, feed pressure of 25 bar and H2/CO2 selectivity of 500.
Modelling of gas diffusion in mesoporous tin dioxide (sno2) as gas sensor in detecting acetone vapour
(2021-01-01)
Mohan, Khamini
Mesoporous semiconductor based gas sensors have been extensively researched and employed in the detection of traces poisonous and flammable gases such as nitrogen dioxide (NO2), carbon monoxide (CO), sulphur dioxide (SO2) and volatile organic compounds (VOCs) such as ethanol, methanol and acetone which are dangerous to both people and the environment. In this research, mesoporous tin dioxide based gas sensor, SnO2 is utilized due to its low cost, high sensitivity and quick response. In order to determine the most effective techniques for optimising the gas sensing properties of mesoporous SnO2, the effect of acetone concentration and operating temperature on the sensitivity of a gas sensor was investigated using a diffusion mechanism model. The gas detecting mechanism was controlled by Knudsen diffusion of the target gas through the porous film and its interaction with adsorbed oxygen, which followed a first-order reaction kinetic. In the diffusion mechanism model equation, a general expression of sensitivity, S (Ra/Rg) as a function of pre-exponential constants, α0 and k0, reaction activation energy for gas dependent, Ea, universal gas constant, R, temperature, T, concentration, 𝐶𝐴𝑠, film thickness, L, reaction activation energy for temperature dependent, Ek, pore radius, r and molecular weight of target gas, M was derived under steady state condition. Theoretically, the variations of sensitivity with the sensor operating temperature resulted in a bell-shaped curve with optimum temperature, whereas increasing gas concentration resulted in increased sensitivity before saturation was attained. When comparing the previous result with the MATLAB simulation, it is clear that the sensitivity increases as the temperature rises, resulting in a linear line rather than a bell shape curve. This can be said the developed model is not suited for the stimulated various operating temperature. The model was used to do a sensitivity analysis based on film thickness, L, and pore radius, r. According to simulation results, sensitivity improved with decreasing layer thickness at 300oC because of greater interaction between the gas to be detected and the sensor surface. The sensitivity of the gas sensor increased with increasing pore radius in the model at a given temperature of 300 oC, which can be explained adequately by the equation of Knudsen diffusion coefficient, Dk.
Conentrating of phosphate with simultaneous removal of sodium chloride via nanofiltration
(2021-01-01)
Vengedesweren, Durgashene
Recovery of phosphorus has been gaining importance due to its natural scarcity and high economical value. Aquaculture and poultry effluent with significant phosphate content required further treatment before discharging to the environment. However, its trace quantity makes the whole process not feasible. Moreover, the presence of salt (NaCl) makes the effort to recover the phosphate as fertilizer less attractive due to its unwanted salinity. In this study. nanofiltration had been tested to recover/concentrate the phosphate ions and at the same time removing the sodium chloride. The study was conducted using Desal DK5 membrane in dead-end mode using Dead End Stirred Cell at different pressures and concentration to investigate the effect of transmembrane pressure (TMP) and feed concentration on the rejection of phosphate ions, average permeate flux and concentrating factor. The highest phosphate ion rejection, 99.86%, was achieved at the lowest pressure, 2 bar, and lowest concentration of potassium dihydrogen phosphate solution (20 ppm). However, in the same parameter, the permeate flux and the concentrating factor (CF) obtained were the lowest compared to other sets of experiment which are 20.15 L/m2 .h and 1.55 respectively. The maximum CF of could be achieved at 6 bar. The removal of NaCl increases with pressure, however the presence of NaCl further reduce the phosphate ion rejection, lowering the average permeate flux and concentrating factor. The results obtained is very promising in terms of harvesting the nutrient from aquaculture effluent and at the same time removing the unwanted salinity.
Modelling of reactive distillation for the production of methyl tert-butyl ether (mtbe) parametric sensitivity study on kinetic model
(2021-05-01)
Mohamed Zubir, Mohamed Fahim
Modelling of reactive distillation for the production of MTBE has been presented in this thesis. A reactive distillation column modelled by using RADFRAC module in the Aspen Plus V10 software for the production of MTBE. The simulation was done on an equilibrium basis. Prior to running the simulation, all the necessary data were collected. The kinetic data which is the coefficients of the equilibrium equation were collected from the equilibrium equation. The values obtained were 357.094, -1492.77, -77.4002 and 0.507563.These values were entered into the Aspen Plus V10 built-in Keq expression. The simulated model was verified by comparing to the published data. Once it was verified, the simulation was then used to carry out parametric sensitivity study on kinetic model. The effect of changes in the kinetic data and four different operating conditions of choice such as the feed flowrate of methanol, the feed flowrate of mixed butenes, the reflux ratio and the composition of isobutylene on the simulation results in terms of MTBE purity and isobutylene conversion were studied in detail. The individual best values for each operating conditions were determined. Then optimization carried out. The optimized values were 209.3 mol/s for methanol feed flowrate, 583.2 mol/s for mixed butenes feed flowrate, 7 for reflux ratio and 0.357 for isobutylene mole fraction. From these set of values, a MTBE purity and isobutylene conversion of 100.00 % obtained successfully. This study shows that the changes in parameters influences the performance of reactive distillation process for the production of MTBE.
Amphoteric adsorbent coating for pharmaceutical waste (diclofenac sodium) removal
(2021-06-01)
Abdul Taib, Muhammad Haziq
The removal of diclofenac sodium (DCF) using a novel amphoteric absorbent coating (AAC) has been presented by this thesis. The formulation of the adsorbent was through a formation of a layer on the surface of a cotton cloth through facile method application using acrylic polymer emulsion (APE), smectite-based clay powder, and cationic polyelectrolyte (EPIDMA). SEM and EDX analysis were conducted for the characterization of the adsorbent coating. The experiments were carried out to study the effect of EPIDMA dosage, concentration, contact time, temperature, and pH of DCF solution on the removal efficiency of the DCF. The optimized percentage removal of DCF is at 77.06% at DCF concentration of 50 mg/L, temperature of 30°C and pH of 3 for 5 hours. Adsorption isotherms were developed to study the adsorption mechanism of the adsorption. This study has shown that the aforementioned parameters influence the performance of the AAC for DCF removal. With high removal efficiency and reusability, AAC was found to be a promising adsorbent for DCF removal from pharmaceutical wastewater system.
Non-catalytic and solvent-free esterification of acetic acid with ethanol using coiled flow inverter for ethyl ethanoate synthesis in food industry
(2021-06-01)
Mohamad Alias, Nurul Aina
Non-catalyzed and solvent-free esterification of ethanol and acetic acid has been conducted in a novel intensified equipment, coiled flow inverter (CFI) to study the mixing performance of CFI in obtaining higher amount of ethyl ethanoate in a shorter time. The experimental study was carried out for very low laminar Reynold Number (Re) varies from 0.26 to 0.51 and for high laminar Re starting from 25 to 75 at constant volume ratio 3 : 1 of ethanol to acetic acid and at constant temperature 80℃. The effects of applying different Re towards the acid conversion and ethyl ethanoate concentration were examined. The mixing profile of fluids in laminar flow conditions were validated in COMSOL Multiphysics 5.5 while the aftermath of changing two CFI parameters either internal diameter of tube or coil diameter,was investigated via computational fluid dynamics (CFD) analysis in COMSOL. The experimental results showed that at very low laminar Re condition, high conversion ( > 80%) of ethyl ethanoate can be obtained as the Re decreased approaching 0. However, moderate conversion (>75%) was attained at shorter time when Re increased in high laminar Re condition due to efficient convective mixing created in CFI at high flow rates. It was also observed that smaller diameter of coil able to create more flow inversions while smaller inner diameter of tube promotes greater mixing flow efficiency in the tube. Optimum diameter of coil and tube inner diameter are crucial to be known as it can promote higher mixing efficiency and product concentration for processing ethyl ethanoate at shorter time for food industry.
Effect of photoperiod onto the uptake rate of phytoremediation of duckweeds
(2021-06-01)
Zulkepli, Syafiqah
Macrophytes or aquatic plants are utilized by their nutrient removal abilities to reduce eutrophication and improve waste product quality. In this study, phytoremediation by L. minor and S. polyrhiza were carried out axenically in synthetic wastewater under control condition to precisely evaluate nutrient removal efficiency of NO3--N, PO43-, NH3-N and pH in the medium sample with different photoperiod. The results showed that ammonia removal was rapid, significant for Lemna sp. at photoperiod 8:16 h and S. polyrhiza at photoperiod 24:0 h with efficiency of 87.8% and 66.3% respectively within 3 days. L. minor was capable of reducing 14.7% of the nitrate. S. polyrhiza at photoperiod 16:8 h achieved phosphate reduction of 68.1% at day 3 to mere 7.17 mg/L PO43-. Both duckweeds showed biomass change increment. L. minor and S. polyrhiza at photoperiod 16:8 h outperformed other photoperiod in nutrient removal. By using the collected nutrient remediation profiles, it can be served as a guideline for the selection of suitable duckweeds and photoperiod in wastewater treatment and as microbiol activity assessment in non-aseptical phytoremediation system.
Model development for turbine energy yield (tey), carbon monoxide (co) and nitrogen oxide (nox) from gas turbine power plant
(2021-06-01)
Wan Anuar, Wan Ahmad Aizat
In order to combat the environmental issues that have been constantly rising since the start of the first Industrial Revolution in the 18th century, many solutions have been introduced and been applied around the world. One of the approaches for overcome air pollution issues from greenhouse gas emissions is by monitoring their release from its most abundant sources, for example, gas turbine power plants.Predictive emission monitoring system (PEMS) is one of the methods for monitoring these greenhouse gas emissions. It is powered by an artificial neural network (ANN)by taking into account the collected data from Kaya et al. (2019) such as ambient temperature, ambient pressure, ambient humidity and many more from selected gas turbine power plants for the emission prediction purpose. Several models will be developed and will be classified according to their responding outputs. Multi input single output (MISO), where carbon monoxide (CO), nitrogen oxide (NOx) and turbine energy yield (TEY) will be operated as separate output and multiple inputs multiple outputs where CO, NOx and TEY will be its output simultaneously. For each model’s type, it will be further classified into the model with input selection and the model without input selection. The performance of the model will be demonstrated by the value of its respective mean squared error (MSE), R and R2. The model with input selection is having almost the same performance as the model without input selection although having fewer input variables compared to the latter. R2 values for each training model with input selection are 0.5094, 0.8260, 0.7573 and 0.6922 for the model with CO, NOx, TEY as output and MIMO model respectively compare to the R2 values for each training model without input selection are 0.5382, 0.8278, 0.7627 and 0.6950 for model with CO, NOx, TEY as output and MIMO model respectively. MIMO model is the better model compared to MISO, even though it combines 3 outputs and could be more complex, but ANN still able to predict accurately. Therefore, developing MIMO model could be better than developing MISO model as it will reduce model times (one model for 3 outputs rather than a separate model for each output).
Esterification of ethanol and acetic acid catalysed by immobilized candida rugosa lipase
(2021-06-01)
Mohd Radzi, Nurul Adila
Ethyl acetate is a versatile ester used as solvent and diluents. The conventional esterification reaction of ethanol and acetic acid was catalysed by sulphuric acid, H2SO4. Enzyme is a sustainable approach for the esterification reaction to produce ethyl acetate. In this study, the esterification reaction of ethanol and acetic acid catalysed by immobilized candida rugosa lipase (CRL) in n-hexane was optimized. The free CRL was immobilized by physical adsorption on support, Amberlite XAD7 which resulted in specific activity of 0.13 U/mg. The effect of reaction time, temperature, substrate molar ratio and enzyme loading were studied. Maximum conversion of 88% was attained at 2 hours of reaction time, temperature of 50°C, acetic acid to ethanol ratio of 0.5 and enzyme loading of 80 U. Next, the kinetic modelling of bi-substrate enzymatic transesterification of ethyl butyrate was studied using secondary data from research paper. The data was fitted to the rate equation of the kinetic model using non linear regression to obtain the kinetic parameter. Based on the Lineweaver-Burk double reciprocal plot, the transesterification reaction follows ping-pong bi-bi mechanism with competitive inhibition by ethyl caprate. The kinetic parameters obtained was, Vmax = 1.1918 M, Km,A = 0.0117 M, Km,B = 0.1674, Ki,A = 0.1091 M, and Ki,B = 0.0031.
Study on the effect of nitrite and free nitrous acid on cultivation of microalgae
(2021-06-01)
Chan, Jyh Loong
Chlorella vulgaris was widely used as potential nutrients elimination microalgae in wastewater treatment plant due to its high removal efficiency of total nitrogen (TN) and totalphosphorous (TP). The aim of this study was to study the effect of nitrite addition on microalgae cultivation by introduce 0 mg/L, 50 mg/L, and 100 mg/L of nitrite into batch reactors respectively, to investigate the effect of free nitrous acid (FNA) on microalgae cultivation by controlling microalgae cultivation condition in pH 4, 6, and 8 with addition 50mg/L of nitrite into batch reactors respectively, and to evaluate the influence of FNA concentration on the extracellular polymeric substances (EPS) secretion from microalgae by conducting EPS extraction as well as proteins and polysaccharides analysis. The results show that 50 mg/L of nitrite introduced into microalgae cultivation had highest growth rate in the result of oxygen inhibition had been eliminated, while 100 mg/L of nitrite introduced into microalgae cultivation had lowest growth rate because of high FNA concentration presented. Moreover, microalgae cultivation with addition 50 mg/L of nitrite and pH 4 culturing condition show the lowest growth rate, and the growth rate for microalgae cultivated at pH 8 had slightly higher than microalgae cultivated at pH 6. From the aspects of proteins and polysaccharides released in EPS, the peak points for protein (PN) concentration released with condition of pH 4, 6, 8 were 156.06 ug/mL (at first day), 171.35 ug/mL (at seventh day), and 173.71 ug/mL (at ninth day), while polysaccharide (PS) released with pH 4 was up to 91.02 ug/mL at third day and reduced to 13.43 ug/mL at seventh day which almost similar trend with others cultivation systems. In overall, microalgae cultivation with addition 50 mg/L of N and pH culturing condition more than 6 could enhance the microalgae cultivation.
Adsorption of chloramphenicol by activated carbon derived from palm kernel shell via microwave irradiation
(2021-06-01)
Luqman, Farihah
This study aims to synthesis activated carbon (AC) derived from palm kernel shell (PKS) to adsorb chloramphenicol (CAP) from aqueous solution. This palm kernel shell activated carbon (PKS-AC) was produced via physical activation method that involves carbon dioxide (CO2) gasification and heating process via microwave. The effects of preparation conditions of microwave radiation power and radiation time on CAP removal efficiency and AC’s yield were optimized via response surface methodology (RSM). Optimum preparation conditions for PKS-AC were identified, including radiation power of 364 W and 2 min of radiation time. These optimum conditions contributed to relatively high CAP removal of 85.93% and AC’s yield of 37.02%. Through elemental analysis, the total fixed carbon for raw PKS was found to be 40.23% and greatly increased to 71.86% (optimized PKS-AC) after activation process. The equilibrium studies which involved initial CAP concentration, contact time, the temperature of solution and pH solutions based on adsorption of CAP on optimized PKS-AC were performed. The adsorption of CAP onto optimized PKS-AC followed Langmuir isotherm where the maximum adsorption capacities were 22.83, 23.70 and 24.88mg/g for 30°C, 45°C and 60°C respectively. Kinetic studies revealed that adsorption of CAP onto PKS-AC followed pseudo-second order kinetic model while thermodynamic studies confirmed that the adsorption system was endothermic in nature. Mechanism studies described that the CAP adsorption process was govern by film diffusion mechanism model.
Configuration of molecular imprinted polymers for specific uptake of pharmaceutical in aqueous media through radical polymerization method
(2021-06-01)
Mohd Amri, Mohammad Hanif
Precipitation polymerization method was used to prepare molecularly imprinted polymers (MIP) for the uptake of acetaminophen in aqueous media. Acetaminophen, methacrylic acid (MAA), ethylene glycol dimethacrylate (EDGMA), 1,1’-Azobis(cyclohexanecarbonitrile) (ABCN) were used as template, functional monomer, cross-linker and intiator respectively. The molarity of cross-linker and functional monomer were varied for the study of imprinting effect of MIPs. High concentration of cross-linker exhibit poor binding ability of MIPs while high molarity of monomer demonstrate better performance in binding capacity. The optimum MIP was observed from template:monomer:cross-linker molar ratio at 1:58:15 with binding capacity of 3.68 mg/g polymer. Next, pristine PES and molecularly imprinted membrane (MIM) were fabricated using phase inversion method. MIM was prepared by adding optimum MIPs in casting solution for the study of antifouling properties as compared to pure membrane. The relative flux of MIM has showed a poor antifouling behaviour in real wastewater sample while a good performance in synthetic solution. However, MIM and pristine membrane have revealed better rejection of acetaminophen in wastewater at 71.31 and 73.06% respectively.
Optimization of biodiesel production from waste cooking oil (wco) using aspen hysys
(2021-06-01)
Badli, Muhammad `Izzuddin
Optimization of biodiesel production from waste cooking oil (WCO) using ASPEN HYSYS has been presented in this thesis. Waste cooking oil (WCO) is chosen as the raw material because about 40,000 tonnes per year of WCO produced in Asia countries such as China, Malaysia, Indonesia, Thailand, Hong Kong, India, etc. The other ways are to recycle the oil and convert it into a new form of product which is biodiesel that will be useful to reduce the amount of wastes and give the WCO a new life. The simulation was carried out to study the efficiency of the biodiesel production from the membrane reactor since the main reference article use for this project is using membrane reactor taken from “ASPEN HYSYS Simulation for Biodiesel Production from Waste Cooking Oil using Membrane Reactor”. This project will further optimize the biodiesel production using membrane reactor. The process flow diagram (PFD) is also taken from the “ASPEN HYSYS Simulation for Biodiesel Production from Waste Cooking Oil using Membrane Reactor” and were used to simulate the result by using ASPEN HYSYS. The research methodology for the simulation rely on the ASPEN HYSYS software. The list of components for the simulation can be obtained from the HYSYS databanks. The fluid package for the simulation is using NTRL method. The process flow diagram (PFD) for the simulation is referring the article “ASPEN HSYS Simulation for Biodiesel Production from Waste Cooking Oil using Membrane Reactor”. The result was unable to obtained due to many errors occurduring conducting the simulation. The expected result from the hypotheses are the yield of the biodiesel will increase as the temperature and pressure increase. The yield of biodiesel will also increase as the reaction time increase. This study hasshown that the parameters such as temperature, pressure and reaction time play an important role that affecting the yield of biodiesel. Moreover, it shows a potential as new commercialize process due to the less waste is generated because no water is needed to purify the final product.
Modelling of gas diffusion in mesoporous tin oxide (sno2) based gas sensor effect of operating temperatures and gas concentration
(2021-06-01)
Arshad, Muhammad Hafizuddin
The sensitivity of a mesoporous tin oxide gas sensor has been theoretically investigated in relation to gas diffusion phenomena. Diffusion models that comprises original and modified diffusion models were created by using MATLAB with the assumption that the target gas which is the inflammable gas flows inside the film is driven by Knudsen diffusion and react with adsorbed oxygen species via a first-order kinetic reaction. Theoretically, the sensitivity of the gas sensor depicts a bell-curved with the variations of operating temperatures. Whilst, the sensitivity increases with the gas concentrations and subsequently became saturated. However, the original diffusion model unable to predict both trends. The modification of the former equation of diffusion model was carried out in which the film conductance variation against hydrogen gas concentration is found to coincide with the power law. With this modification, a bell shaped was obtained which is in a closed agreement with the experimental result. In additions, the effect of silver, Ag and gold, Au modification of film in SnO2 gas sensor was also simulated. The simulated result in detecting 1-butanol gas shows that the optimum operating temperature was reduced by 150°C for both Ag/SnO2 and Au/SnO2 with higher sensitivity as compared to pure SnO2. Finally, the effect of pore radius, r and film thickness, L on the sensitivity was also simulated in detecting hydrogen gas. The simulated result for the pore radius shows that the sensitivity increases as pore radius increase at the fixed temperature, which is correlate with the Knudsen equation, Dk. For film thickness, the result shows that the sensitivity increases as the thickness of the film decreases due to a stronger contact between the target gas and the sensor's surface.
Evaluation of emulsion liquid membrane on pharmaceutical waste from aquaculture wastewater
(2021-06-01)
Jasni, Mohd Khairul Akmal
Liquid membrane technology is undergoing a significant increase in both research and application as an industrial separation method at the moment. A liquid membrane can be used to isolate a specific solute from a mixture and even extract a solute against its concentration gradient. There are three liquid phases in a liquid membrane system: feed phase, liquid membrane organic phase, and receiving phase. Either a supported liquid membrane or an emulsion (unsupported) liquid membrane can be made. Emulsion liquid membranes are liquid membranes that disseminate the emulsion's membrane phase into the feed phase to be treated. This method was investigated as an alternative process for the recovery of ibuprofen from pharmaceutical waste. The formulations of ELM were studied in order to find the most suitable component. Besides that, some parameter affecting the performance of ELM was also being studied. The parameter involved are agitation speed, emulsifying time, concentration of stripping agent, internal to membrane ratio, and the weight percentage of surfactant and carrier. Based on the result, the most suitable component for ELM was found to be kerosene as diluent, trioctylamine as carrier, and ammonia as stripping agent. It is also being found that, the optimal condition for this emulsion liquid membrane study was obtained at 300 rpm of agitation speed, 15 minutes of emulsification time, a ratio of 1:3 internal to membrane, 0.1 M concentration of stripping agent, and 6 wt% and 2wt% for the weight percentage of carrier and surfactant respectively which yield 84% of efficiency.
Almond shell based activated carbon prepared via microwave irradiated for chloramphenicol removal
(2021-06-01)
Saw, Wen Yi
In this study, low cost and efficient activated carbon (AC) was prepared from almond shell (AS) through microwave irradiation technique for chloramphenicol (CAP) removal. The optimization of almond shell based activated carbon (ASAC) preparation conditions of microwave irradiation power and radiation time for CAP adsorption was done by using Response Surface Methodology (RSM). The optimum preparation conditions determined were at radiation power and time of 490 W and 6 minutes, respectively, which resulted in 96.23% of CAP removal and 41.53% of ASAC yield. The optimized ASAC was characterised through Brunauer–Emmett–Teller (BET) surface area and pore structural analysis, proximate and elemental analysis, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). For batch adsorption study, various operational parameters such as initial concentration, contact time, solution temperature and pH on CAP adsorption were investigated. The experimental data were analyzed using three adsorption isotherm models: Langmuir, Freundlich and Temkin. It was found that the adsorption was best fitted with the Langmuir isotherm model, with maximum CAP adsorption capacity at 63.29 mg/g. Kinetic studies for CAP adsorption indicated that the adsorption process followed a pseudo second order (PSO) kinetic model. The thermodynamic parameters such as standard Gibbs free energy (∆𝐺°), standard enthalpy change (∆𝐻°) and standard entropy change (∆𝑆°) were determined. Based on the thermodynamic parameters, the adsorption of CAP onto ASAC was an endothermic and spontaneous process.
Steady state multiplicity in the reactive distillation of methyl tert-butyl ether (mtbe) synthesis stability analysis
(2021-06-01)
Adnan, Fietriey Atiera Shahida
Reactive distillation (RD) has garnered a lot of attention due to its tremendous potential for process intensification. Due to that, the methyl tert-butyl ether (MTBE) synthesis in reactive distillation (RD) column was studied and an equilibrium model was developed by using Aspen Plus V10. The proposed model was validated by comparing the simulation results with the published simulation results from the literature. The model obtained high isobutene conversion and MTBE purity for heterogenous catalyzed system, which is desirable in the industrial MTBE production process. The comparisons on temperature profiles and liquid composition profile of RD column also yielded promising results. The proposed model can be used as a tool for the analysis of multiple steady state in RD column of MTBE. It is concluded that only single steady state of MTBE synthesis that can be found when using the same column configuration in Aspen Plus V10. Sensitivity analysis is conducted to study the influence of reflux ratio on the isobutene conversion. From this analysis, it was shown that MTBE purity and isobutene conversion were maximum at reflux ratio of 7. Stable reactive distillation of MTBE can be achieved since the equilibrium modelling has developed higher steady state solution.
Magnetophoretic migration of magnetic nanoparticles through cellulose matrix
(2021-06-01)
Mohd Salleh, Muhammad Sufian
The migration of magnetic nanoparticles (MNPs) through cellulose matrix has been presented in this thesis. The experiment was carried out to study the influence of colloidal stability, aggregation of MNPs, concentration, the pore size of the cellulose matrix, and strength of magnetic field on the magnetophoresis of MNPs through the complex structure of cellulose. Magnetite, Fe3O4 were used as the MNPs to study the magnetophoresis under an Optical microscope. All the captured images of the magnetophoretic phenomena were analysed by using NIH ImageJ. A simple setup of the experiment was done by placing a magnet 2 cm away from the initial point of MNPs was injected on the Whatman chromatography paper. Based on the experiments conducted, 100 mg/L of poly (sodium (4) styrene sulfonate) polyelectrolyte (PSS) coated MNPs were able to migrate through grade 4 paper after 30 and 60 s of magnetophoresis with 0.007492 % and 0.0162 % of the area covered at 2 cm, respectively. As for naked MNPs with the same conditions, the area covered after 30 and 60 s is 0 and 0.00133 % respectively. It was found that the area covered for the magnetophoretic motion of MNPsthrough grade 5 paper was lower than grade 4 paper, whereas at 1.5 and 2 cm the area covered is 0.00245 % and 0.00294 % respectively. Besides, a higher concentration of MNPs solution will limit the magnetophoresis of MNPs through the matrix due to the formation of aggregation that inhibits the motion of the particles from passing through the pore of the cellulose matrix.
Conceptual study of enzymatic wax ester synthesis in the batch reactor at steady state and isothermal conditions
(2021-06-01)
Ngu, Hung Hui
Wax ester is one of the most important ingredients with its many potential applications in the food industry, cosmetic industry, and pharmaceutical industry. Enzymatic esterification is preferable over chemical reaction due to its mild reaction and being more environmentally friendly. A mathematical model based on the mol balance in the batch reactor and Ping Pong Bi Bi enzymatic rate equation was developed to study the kinetic parameter, thermodynamic parameter and operational parameter of enzymatic esterification in batch reactor. POLYMATH software (version 6) was used for the simulation of this mathematical model. The model was validated with experimental data obtained from literature sources while the values of certain parameters were estimated. From the validation, the experimental and theoretical data shows a good agreement (0.88 ≤ R2 ≤ 0.98) which proves that the model and the estimated kinetic and thermodynamic parameters are accurate to represent the actual process as R2 greater than 0.8. According to the findings and simulation results, a lower value of Km and ∆Gcat leadsto a higher production yield as it indicates lower energy is required for substrate binding and to catalyze the reaction. On the other hand, a higher value of Ki and ∆Ginac are recommended for an enzyme because it indicates the enzyme is less affected by the inhibitor and resistance to deactivation at a higher temperature. Based on POLYMATH, optimum esterification conditions were 50°C temperature, 1.0×10-5 mol/L enzyme concentration and 1:2 fatty acid – fatty alcohol mole ratio. Profiling of enzyme is performed to study the inhibitory pattern. It found that, fatty alcohol shows more severe inhibition effect over fatty acid toward rate of reaction. Overall, my work on simulation is sufficiently adequate and has improved my understanding on the implementation of the production process on an industrial scale from laboratory scale.
Synthesis of pet mwcnts electrospun nanofiber with polyester fiber support for methylene blue removal
(2021-06-01)
Steven Ling, Guang Hu
Occurrence of water pollution including contamination of dyes and heavy metals causes the quality of water to decrease significantly. One of the major dyes found in the wastewater is methylene blue (MB). The purposes of this study were to synthesis polyethylene terephthalate/multi-walled carbon nanotubes (PET/MWCNTs) electrospun nanofiber with polyester fibers(PES) as support and to investigate its adsorption performance on MB. The method to synthesis PET/MWCNTs electrospun nanofiber was using electrospinning process method. There are three major parameters such as contact time, adsorbent dosage and initial dye concentration were to be evaluated through batch mode experiment. The optimum contact time obtained for adsorption was 1440 minutes. PES+PET/MWCNTs had adsorption capacity of 0.3398 mg/g and removal efficiency of 13.63% which had better performance as compared to PES having adsorption capacity of 0.2529 mg/g and removal efficiency of 11.62%. The adsorption capacity showed a decreasing trend and the MB removal percentage showed an increasing trend when the adsorbent dosage increased. However, there was an increment in adsorption capacity and a reducing trend in MB removal percentage when the initial dye concentration increased. For adsorption isotherm, it was found that Langmuir isotherm model is relevant with the experimental data as compared to Freundlich and Temkin isotherm model. Pseudo-second-order kinetic model was more favourable in providing the details of the kinetic studies in MB adsorption. Thus, PET/MWCNTs electrospun nanofiber can be a potential adsorbent in removing MB dye from wastewater.

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