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.
Simulation of reactive distillation column of methyl tert- butyl ether production
(2021-06-01)
Shanmugasundaram, Parrathen
Reactive distillation is an efficient technique of combination of both reaction and separation in a single unit beneficial for equilibrium-limited reactions, cost-effective , reduce energy and improvement purity of the product. The usage of reactive distillation column has increased attention because of its high potential for process intensification and therefore this process needs to be studied fully so that the reaction conversion and purity of the product are assured before its implementation in industrial scale. In this work, Aspen Plus was used for simulation of reactive distillation column where methanol and butene undergo esterification reaction to produce Methyl tert-butyl ether (MTBE) and undergo continuous separation process. Firstly, the results are compared for both literature and simulation studies. The simulated results obtained by Aspen Plus showed that it is acceptable range since the simulation values obeyed that of the literature with a purity errors of top and bottom for MTBE is 0.0048% and 0.0026% respectively. In addiction, simulation results have been performed for sensitivity analysis. Sensitivity analysis on the same RadFrac model showed that reflux ratio of 7, number of reactive stages at 10, and reboiler of 11.45have significant effects on met MTBE purity. Sensitivity analysis conducted shows that the MTBE purity were maximum at reflux ratio 7. The best feed location for butene at stage 3 while methanol feed at stage 12.
Gravitational ultrafiltration of river water fouling and cleaning efficiency study
(2021-06-01)
Bachok @ Joffri, Luqman Hakim
Gravity Driven Ultrafiltration System is a promising technology which could produce potable water to the community with no electricity and proper wastewater treatment. This project focuses on the construction of the non-point source, modular type GDU system to filter the river water using the Krian river as source water. The GDU systems are tested under both depleting and constant hydrostatic pressure conditions. Underdepleting hydrostatic pressure at 40 cm, the highest flux was found at 0.58 LMH and it reduce to almost zero due to reduction of hydrostatic pressure and exhaustion of river water in the module. The module can recover its flux up to 85.17% after being backwash for 5 cycles. Under constant hydrostatic pressure, it was found that 40 cm length hollowfibres produce the lowest permeation flux stabilization due to the larger extent of fouling. Therefore, the tendency for fouling is higher at longer membrane. This can be seen through the characterization of membrane using SEM and FTIR by comparing the pristine membrane with the fouled membrane. Water quality test using different parameters are used to determine the amount in the river water before and after undergoing GDU system. It was found out the concentration of parameters tested on the permeate water is lesser compared to the river water, especially on the bigger molecule. The quality of the permeate is safe for human activity according to the guideline outlined by WHO. The module can recover its flux up to 36.83,86.26 and 94.32% for 40,35 and 30 cm respectively after backwash for 5 cycles. The modular GDU system is promising to provide the clean water for the community that is deprived of electricity and water treatment facilities.
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.
Microwave – assisted extraction (mae) of rhizome kaempferia parviflora crude and its biological activity
(2021-06-01)
Mohammad Gial, Mohamad Anwar
Extraction is a process to separate the desired natural products from the raw materials. It has been used in various industry such as food and pharmaceutical industries to achieve certain level of nutrients in the products. However, traditional extraction method required a large volume of solvents and longer extraction time. Hence, advanced extraction which is microwave-assisted extraction was carried out. This research study focusses on green extraction technique where the solvent used is water. Microwave-assisted extraction (MAE) was optimized by Response Surface Methodology (RSM) to enhance the extraction of rhizome K. Parviflora crude. The optimization was done to get the optimum microwave power, microwave extraction time and solvent to feed ratio with maximum response. Central Composite Design (CCD) was selected as a model for RSM to evaluate the first and second-order polynomial model. The analysis of variance was used to evaluate the model fitness and optimal condition. Considering the maximum content of extracted yield, total phenolic content and antioxidant activity, the optimal conditions for all investigated response were obtained at microwave power of 360 W, microwave time of 2 min and solvent feed ratio of (10:1). Under the optimal condition, obtained K. Parviflora crude extract contained 16.72% yield of crude extract, 18.24 μg /ml of total phenolic content and 142.681 μg/ml of antioxidant activity. The study revealed that the response surface methodology (RSM) is an efficient statistical method for preparing appropriate empirical model related to the independent variables and predicting the optimum conditions influencing K. Parviflora crude extract. Microwave-assisted extraction is an environmental-friendly technique for extractions of bioactive compounds and an attractive alternative procedure in industry food and traditional herb.
Fabrication of anisotropic poly (4-methyl-1-pentene) membrane for co2 and n2 gas separation
(2021-06-01)
Zainuddin, Muhd Izzudin Fikry
Carbon dioxide (CO2) separation from flue gas with the use of membrane technology has become the focus of researchers over the past decades due to its lower energy consumption and cheaper alternative. In this thesis, anisotropic poly(4-methyl-1-pentene) (PMP) was studied to determine the feasibility of using PMP to separate CO2 from nitrogen (N2) gas. A full dense PMP membrane with various PMP wt% was fabricated at both 20 and 70 ℃ to determine the effect of temperature on dense layer of the membrane. Water contact angle and FTIR-ATR was used to characterize the fabricated PMP membrane. The water contact angle of PMP membrane surface without modification such as plasma treatment or coating that have been obtained ranged between 105⁰ and 116⁰ which makes the membrane to be classified as hydrophobic membrane. The SEM image on the cross section of the full dense PMP membrane also showed no significant difference of the dense layer between the membrane that undergo dry phase inversion at 20 ℃ and 70 ℃. CO2 and N2 gas permeance as well as the selectivity does not differ greatly with fabrication temperature. 5 wt% PMP fabricated at 20 ℃ seems to be the best condition to fabricate anisotropic PMP membrane based on the gas permeance test. The CO2 and N2 permeance is 5.91 ± 0.29 GPU and 0.51 ± 0.03 GPU respectively, and with CO2/N2 selectivity as 11.57 ± 0.10. The parameter was then used to fabricate anisotropic PMP membrane with varying dry phase inversion time from 10 to 60 seconds. The CO2 permeance increased by 10 times while the N2 permeance increased by 5 times on average which makes the CO2/N2 selectivity dropped by half from the full dense PMP membrane. SEM imaging is used to observe the effect of dry phase inversion time on the thickness of the dense layer of the fabricated anisotropic PMP membrane. With 40 second dry phase inversion time, it appears to be the best duration to fabricate the anisotropic PMP membrane. The CO2 and N2 permeance is recorded to be 51.49 ± 1.56 GPU and 9.90 ± 0.58 GPU respectively with selectivity of CO2/N2 gas as 5.21 ± 0.15 with the least deviation. Water-ethanol mixture is not suitable as coagulation bath due to the immiscibility between cyclohexane and water. Using higher alcohol chain will reduce the solubility parameter between cyclohexane and the alcohol which will cause the reduction in porosity of the PMP membrane in the porous section. In our case, we conclude that introducing water component as a mixture to the coagulation bath is not suitable for the production of PMP membrane with cyclohexane as its solvent as water and cyclohexane is immiscible and will form two-phase 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).
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.
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.
Optimization and thermal degradation kinetics of cellulose nanoparticles (cnps) production from coconut fiber
(2021-06-01)
Tim, Mau Sean
Optimization and thermal degradation kinetics of the cellulose nanoparticles (CNPs) production from coconut fibers were presented in this research project. The research project was carried out by using the data collected from the thesis with the title of ‘Dissolution of Natural Fiber using Ionic Liquid for Production of Cellulose Nanoparticles’ by Nadzirah binti Yahya. For optimization part, the CNPs production from coconut fibers was simulated using the Response Surface Methodology (RSM) via Central Composite Design (CCD) in Design Expert software to determine the relationship between the affecting parameters (extraction time, extraction temperature and ratio of coconut fiber (CF) to ionic liquid (IL)) on the response (ultrafine CNPs distribution). The simulation results showed that both the extraction temperature and CF:IL ratio were more significant to the regression model. The maximum ultrafine CNPs distribution obtained through the optimization process was 58.074 %, under the operating conditions of 30 mins of extraction time, 69.518 °C of extraction temperature and 0.01 w/w of CF:IL ratio. For the thermal degradation kinetics study of CNPs produced from coconut fibers, both the model-free isoconversional Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods were used to determine the activation energy, Ea of the CNPs. However, the calculated results of Ea were not satisfied, which were ranged from -0.039 to -3.134 kJ/mol. The values deviated very much from the Ea value of common CNPs, and the possible source of error was predicted to be from the inaccurate results from the collected data.
Dynamic simulation of phenol adsorption using microwave induced coconut shell activated carbon
(2021-06-01)
Lim, Kai Wen
Coconut shell is a cheap, sustainable, and abundant resources in Malaysia as a raw material for making the activated carbon to be used as adsorbent in the adsorption process. In this study, the adsorption performance of the microwave induced coconut shell activated carbon is tested on the continuous adsorption of phenol by using ASPEN Adsorption software. The effects of the process parameters such as flow rate, initial phenol concentration and adsorbent bed height to the adsorption performance are investigated and the results showed that those 3 parameters have a significant effect on the adsorption performance. The adsorption performance of the phenol by using the microwave induced coconut shell activated carbon is evaluated by using the breakthrough time and the breakthrough adsorption capacity. The phenol adsorption performance is studied for both experiment and simulation and the results show a similar trend on the varying of process parameters. Higher amount of phenol is adsorbed on the activated carbon when the feed flow rate is lowered. In the other hand, the amount of phenol adsorbed also increased as the initial phenol concentration and bed height increased. The breakthrough behaviour of phenol adsorption is predicted by using three dynamic models which are Thomas model, Yoon-Nelson model and Adams-Bohart model. All three models are capable in providing a good fit to both the experimental data and simulation results based onthe high r2 values.
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 copper (ii) ions in wastewater using mangrove-based activated carbon
(2021-06-01)
Bong, Sock Ving
Water pollution due to the discharging of industrial wastewater consisting of heavy metals has become a serious issue. A cheap adsorbent is required to support the pollutant adsorption technique. Thus, the main goal of the research is to optimise the preparation and adsorption conditions of activated carbon from cheap raw materials. The production of mangrove-based activated carbon using microwave heating activation is cost-effective because mangrove is abundantly available in Malaysia and microwave heating requires less time and lower electricity. The optimal activated carbon was produced at 616 W and 2 mins under nitrogen flow. The ideal KOH: Char ratio was found to be at IR of 0.75 with 99.67% of activated carbon yield and 77.256% of copper (II) ions removal. The AC was examined by Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherm and elemental analysis. Aside from optimisation, the adsorption process using the mangrove adsorbent was examined under various conditions. From the experimental data, the adsorption reached equilibrium after 3 hours at 10ppm and 60℃. Freundlich isotherm models with R2 values of 0.9995 and 1/n smaller than one explains the multilayer and heterogenous nature of adsorption. The maximum adsorption capacity of mangrove based activated carbon obtained using Langmuir Isotherm was 33.557 mg/g, which shows its intrigue value as a potential adsorbent. Furthermore, the data was well fitted to Pseudo-second-order kinetics models with R2value of 0.9997. Finally, the thermodynamic analysis revealed that the adsorption studied is endothermic process, and the adsorption is spontaneous at 50 and 60°C.
Air pollution index estimation model based on artificial neural network
(2021-06-01)
Mohammed Nasser, Al-Subaie
Environmental conservation efforts are always dealing with a complex problem because it involves a large number of variables. However, choosing a correct model structure, and optimum training algorithm with minimum complexity is crucial. Therefore, a dimensional reduction method was implemented based on the multiway principal component analysis (MPCA) method. Three models were built in first part; ozone estimation model, particulate matter 10 (PM10) estimation model, and air pollution index (API) estimation model. Six inputs were used in ozone and PM10 models, which are nitrogen oxides( NOx), carbon monoxide (CO), sulphur dioxides (SO2), wind speed, air temperature, and relative humidity. After that, ozone and PM 10 were used as input to the API estimation model. The result shows that the implementation of the MPCA has insignificant improvement on the overall correlation factor due to the high nonlinearity of data.
Riboflavin adsorption on mesoporous carbon by using aspen adsorption simulation
(2021-06-01)
Suhaimi, Muhammad Alif
Riboflavin is one of the B vitamins and essential component of flavin mononucleotide and flavin adenine dinucleotide. Riboflavin is yellow and naturally fluorescent when exposed to ultraviolet light. In this project, adsorption of riboflavin was analysed using Aspen Adsorption software. There are 3 condition that consider performing this simulation which is initial flow rate (10, 20, and 30 mL/min at constant bed height and initial concentration of RF, 2 cm and 50 ppm respectively), bed height (changing the bed height 2 , 4, and 6 cm at constant initial flowrate and initial concentration of RF, 10 mL/min and 50 ppm respectively), and initial concentration varied the initial concentration at 50, 100, and 200 ppm at constant initial flow rate 10 mL/min and 2 cm bed height). Taking 303.15 K for the fixed temperature for all the simulation. Breakthrough curve of riboflavin adsorption show shorter time taken to reach the breakthrough point by increasing the initial flow rate and initial concentration of riboflavin for both simulation and experimental. Otherwise, increasing the bed height will give negative result on adsorption of riboflavin. The study of riboflavin adsorption also being analysed by using three different model development ( Thomas, Yoon-Nelson, and Adam-Bohart ). The result show Thomas Model and Yoon-Nelson Model exhibit better performance than Adam-Bohart by analysing the R2 value.

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