Pusat Pengajian Kejuruteraan Kimia - Monograf

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Adsorption isotherms and kinetic studies on the removal of lead (ii) ions by rubber seed coat
(2021-06-01)
Nor Hisyam, Nur Fatini
Rubber seed coats (RSC) were treated with acid and base to investigate the removal of lead (II) ions by adsorption process. Among all biosorbents that were investigated, base treated rubber seed coats showed the highest removal percentage of lead (II) ions. The experimental data were fitted to Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Halsey isotherm models to further describe the biosorption process. Generally, from adsorption isotherm models, base treated RSC have the characteristics such as having monolayer coverage of adsorbate on biosorbent surface, adsorption process of indirect interaction between adsorbent with adsorbate and it exhibits physical adsorption process. Next, experimental data were fitted to pseudo first-order, pseudo-second-order, intraparticle diffusion and Elovich model. RSC showed best fit in pseudo-second-order kinetic model. RSC showed that surface adsorption may be contributing to the rate controlling step in the biosorption of lead (II) ions on RSC and based on Elovich kinetic model, chemisorption may be the rate determining step at higher concentration of lead (II) ions.
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.
Adsorption of chloramphenicol by ordered mesoporous carbons using aspen simulation
(2021-07-01)
Mohammad Nasruddin, Muhammad Alif Aiman
Chloramphenicol (CAP) is found abundance in composition of water that hazardous and cause harmful to human health if consume and to ecosystem. Therefore this study is about the adsorption/removal of chloramphenicol by ordered mesoporous carbons (OMC) using the Aspen Adsorption® simulation. First and foremost in the simulation, the constant parameters need to be identified and manual calculated in the Microsoft Excel such as isotherm parameters (IP) values, adsorbent and bed porosity, tortuosity and the global mass transfer coefficient (MTC). The first simulation operation condition are manipulating the initial CAP concentration (50, 100 & 200 mg/L) and constant the bed height (2cm) and flowrate (10 mL/min). At 50 mg/L initial concentration show the longest breakthrough (925 minutes) and exhaustion time (1600minutes). For the changing in the flowrate (10, 20 & 30 mL/min), the longest breakthrough and exhaustion time is at 10 mL/min which 925 minutes and 1600 minutes respectively. Vice versa for the effect of the bed height (2, 4 & 6 cm) on adsorption, which show the longest breakthrough (2700 minutes) and exhaustion time (4500 minutes) at 6 cm. In the simulation column adsorption studies, Thomas and Yoon-Nelson model shows the highest R2 value (0.999) compared to Bohart-Adams model (0.950-0.99).
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.
Adsorption of lead (ii) from aqueous solution by activated carbon developed from mangrove wood by microwave radiation heating
(2021-08-01)
Tan Lekha @ Malek, Hajar
Activated carbon is an adsorbent that is large in surface area with a great amount of porous structure formed on it. Activated carbon is utilised as an adsorbent because of the effectiveness for adsorbing a wide type of contaminants in liquids or gases. This study aims to develop an activated carbon derived from the mangrove wood to adsorb heavy metal which is lead (II) ions. The adsorbent was activated via physical activation by microwave heating and gasification of nitrogen (NO2). Study on the effects of the operating condition on the activation of the adsorbent was performed by exposing the char at different radiation time and radiation power. The optimization of the activated carbon was performed by using response surface methodology (RSM). The optimum condition obtained for the prepared activated carbon was at radiation time of 2 minutes and radiation power of 528.66 watt. Removal of lead (II) ions in batch system was performed by investigating several parameters such as initial lead (II) ions concentration, contact time, solution temperature and solution pH In this studies, the highest removal of lead (II) ions in a batch system was at pH 4, initial lead concentration of 10 mg/L and the optimum contact time of 30 minutes. The isotherm studies were performed and the results show that the adsorbate-adsorbent system fitted well to the Langmuir isotherm model compared to Freundlich isotherm model. In this study, the adsorption reaction performed by using activated carbon prepared from mangrove wood was found to be effective in removing high percentage of lead (II) ions.
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.
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.
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.
Application of kinetics – thermodynamics model and adsorption mechanisms for inhibition of acid corrosion on mild steel by red onion peel extract
(2021-06-01)
Mansor, Nuramirah
The study of kinetics–thermodynamics parameters and adsorption isotherms of the inhibition of corrosion mild steel in acid medium using red onion peel extract (ROPE) as green corrosion inhibitor was carried out. The inhibition efficiency was found to increase with increasing inhibitor concentration but decrease with increasing temperature of acid medium because at higher temperature the mild steel is oxidized at higher rate and causing the inhibitor to desorb back from mild steel surface. The value for heat of adsorption, Qads ranged from -39.89 to -41.71 KJ.mol-1 indicates that the reaction is exothermic. The adsorption data fitted well to Langmuir adsorption isotherm model. Thermodynamic equations were used to determine the activation energy (Ea), enthalpy change (∆H) and entropy change (∆S). The adsorption isotherms such as Langmuir, Freundlich, Flory–Huggins, Temkin, and Frumkin were used to evaluate the change of Gibb’s free energy from the adsorption equilibrium constant, Kads, value. The adsorption of the inhibitor on surface of mild steel was found to be spontaneous and consistent with the physical adsorption mechanism as ∆Gads is negative value and less than -20 KJ.mol-1.
Application of response surface methodology (rsm) for optimization paramter of lscf-cuo for intermediate temperature solid oxide fuel cells
(2021-07-01)
John, Jonathon
Optimization of lanthanum strontium cobalt ferrite mixed with copper (II) oxide (LSCF-CuO) for the synthesis condition is carried out to maximize the fuel performance. The optimization is carried out using Response Surface Methodology; Central composite design (CCD), Historical data and Optimal-D models in the Design-Expert (12) software and the comparison between them have beenmade. The optimization was carried over a done experiment to analyze the parameters, sintering temperature (°C) and CuO concentration (wt%) on the polarization resistance Ωcm-2 which indirectly affect the fuel cell performance. The adequacy analysis for all the 3 designs shows normal distribution plot which indicate the accuracy of the quadratic to predict the response. Based on ANOVA analysis for all the 3 designs, p value of less than 0.05 for the sintering temperature and CuO concentration indicate a significant effect of these parameters on the polarization resistance. Based on the fit summary analysis, the designs shows good fit of quadratic models since the R2 for CCD, Historical data and Optimal-D are 0.9911, 0.9936 and 0.9959 respectively (closeto unity). The aim of the optimization is to minimize the polarization resistance and therefore Optimal-D model shows the good optimization result since it exhibit the lowest Rp of 0.11 Ωcm-2 compared to Historical data (0.16 Ωcm-2 ) and CCD (0.12 Ωcm-2 ). The optimized sintering temperature and CuO concentration for Optimal-D were 656 °C and 1.65 wt % respectively.
Application of response surface methodology (rsm) for the optimization parameters of hydrochar production from coconut husk using hydrothermal carbonization
(2021-07-01)
Zahrimi, Mohamad Mifzal Nur Hakim
An ideal and optimum conditions for maximum production of hydrochar yield of coconut husk via hydrothermal carbonization (HTC) were investigated using optimization method. The optimization and analysis of significant operating conditions which were reaction temperature and residence time was done based on the experiment conducted in the previous study at hydrothermal carbonization temperature range from 180 to 240°C and 48 to 96 h. The simulation was carried out to study the effect of operating conditions (reaction temperature, residence time and biomass-water ratio) on hydrochar through hydrothermal carbonization of coconut husk with the range taken from previous studies at 180-260°C, 0.5-2 h and 1:5-1:15 wt% respectively. Simulation data was optimized and analysed by using response surface methodology (RSM) in Design Expert to design the experiments. Based on chosen Central Composite Design (CCD) method, a quadratic model was developed to correlate the operating conditions and hydrochar yield. The optimized hydrochar yield from the experiment conducted in previous study was obtained at 60.669% at 194.121°C and 48 h. From the simulation data, hydrochar yield was obtained at 70.909% at 180°C, 0.5 h and 1:15 wt%.
Aquaculture wastewater treatment using a combination of ozonation process and activated carbon adsorption
(2021-06-01)
Mohd Shukri, Farah Anis
This study investigates the effectiveness of ozonation treatment alone and combination of ozonation treatment with activated carbon adsorption to treat the synthetic aquaculture wastewater. The solution of a synthetic dye, methylene blue was ozonated using an ozone generator in order to illustrate the color removal of aquaculture wastewater. The experiment was conducted under a constant ozone dosage of 600 mg/h and the concentration was observed throughout 60 minutes. The factors affecting the process of degradation were investigated, i.e., the effects of initial dye concentration (mg/L) and effects of pH. Apart from that comparison between ozonation and ozonation-activated carbon adsorption was observed. The ozonation was done in 1L beaker with 500 mL dye solution. The initial concentration studied in this work were 30 mg/L, 45 mg/L and 60 mg/L meanwhile pH 3, pH 7 and pH 9 for pH studies. As a result, the initial dye concentration of 60 mg/L took the longest reaction time to achieve 90% of color removal efficiency followed by 45 mg/L and 30mg/L. This happened as ozone became the limiting substances in the reaction since the ozone dosage supplied was kept constant. Eventually, within 60 minutes, all color were successfully removed for all the initial concentrations. Apart from that, the degradation of methylene blue with ozone treatment had the highest color removal at pH 9 which was under basic condition and the lowest at pH 3 which was under acidic condition. Ozonation performed best under alkaline condition as more hydroxyl radicals could be generated compared in acidic condition. Besides that, the rate of degradation was enhanced with the combination of activated carbon adsorption and ozonation treatment.
Aspen simulation of methylene blue adsorption using coconut shell based activated carbon
(2021-07-01)
Zainol, Nurhidayah
Methylene Blue (MB) is a cationic dye that has been found in wastewater. In this project, the adsorption of MB through dynamic simulation was carried out and the simulation data were validated with the experimental result. It was analyzed based on the effect of initial concentration, flow rate, and bed height at constant temperature 303.15 K. According to predicted breakthrough curves, MB is adsorbed in greater amounts on coconut shell activated carbon and has highsaturation time at lower initial concentration, lower flow rate and higher bed height in all experimental and simulation. The breakthrough curves were analyzed using Thomas, Bohart-Adams, and Yoon Nelson models under different conditions. The linear form of the models was used to fit the experimental and simulation data. Linear regression analysis for both data indicated that each model has its significant characteristics such as adsorption capacity (Thomas model), rate constant (Bohart-Adams model) and 50% breakthrough (Yoon Nelson model). The results showed that both experimental and simulation data well represented by Thomas model, while both Bohart-Adams and Yoon-Nelson model were also found adequate for explaining the dynamic behaviour of the column. The R2 value for simulation data close to unity, however the R2 for experimental data is poor for Thomas model. The model proposed by simulation data has a better fit than the experimental results. In any case, the overall model is encouraging, implying that the accuracy assumptions, equations, and estimated model parameters are appropriate.
Biodiesel production using reactive distillation optimization and comparative simulation study using aspen
(2021-07-01)
Chuah, Jing Xuan
Depletion of fossil fuels in the recent years had led to attention of researcher to develop potential renewable energy as the fossil fuel substitute. Thus, biodiesel issuggested since it is a good replacement of fossil fuels as a ‘clean energy source’. However, due to high cost of raw material and operating expenses in conventional biodiesel production, biodiesel is considered not economically competitive compared to petroleum-based fuel. This limitation can be overcome by process intensification (PI) technology. PI technology is applied in intensified biodiesel production by using reactive distillation column to replace methanol recovery column and reactor. Reactive distillation (RD) is a process intensification technique that combines chemical reaction and distillation in a single equipment. To minimize the energy consumption in RD column, sensitivity and optimization analysis are conducted to study the effect of operating parameters such as feed temperature and reflux ratio on reboiler heat duty. Results from sensitivity analysis showed that reboiler heat duty is directly proportional to feed temperature but inversely proportional to reflux ratio. Optimized results showed that optimum condition for efficient production of biodiesel with minimum consumption of energy is at 145oC of feed temperature and reflux ratio at 1. Besides, the process gains obtained through intensification of a conventional biodiesel plant by addition of a reactive distillation column is studied. It is found that intensified process has higher conversion of Jatropha oil into biodiesel compared to conventional process with reported conversion rate at 48.19% and 32.52% for intensified and conventional process, respectively. From aspect of energy analysis, hot utility requirement in intensified process is 60.70% less than that required for conventional process with reported hot utility requirement at 7.702×104cal/s and 131.96×105cal/s for intensified and conventional process, respectively. Besides, reboiler heat duty in intensified process is 21.84% less than in conventional process with reported reboiler duty at 69034.1kW and 88327.1kW for intensified and conventionalprocess, respectively. From aspect of exergy analysis, result showed exergy change across reactor and methanol recovery column in conventional process are -10.39kW and -25.54kW, respectively. Whereas exergy change across reactive distillation column in intensified process is 91.15kW. This implies that exergy is lost or wasted in conventional process, whereas in intensified process exergy is gained within reactive distillation column. Thus, this reactive distillation column utilizes fully exergy gained from other sources.
Comparison between box-behnken design and central composite design for optimizing the biosynthesis of silver particles using curcuma longa extract
(2021-07-01)
Thinagar, Saranya
Curcuma longa (C. longa) is a rhizomatous herbaceous perennial plant that belongs to the Zingiberacae, the ginger family. The most active compound found in the C. longa is curcumin that contains polyphenol which is the vital component activating the reduction process during silver nanoparticles (AgNPs) synthesis. In a biosynthesis process, optimization process is important to develop a process that results in higher yield and efficiency. The goal of this study is to determine the optimum process conditions, comparing the Box–Behnken Design (BBD) and Central Composite Design (CCD) in optimization process and elucidating the main interacting parameters on the biosynthesis of silver particles using C. longa extract, which includes: Concentration of C. longa extract (g/L), concentration of silver nitrate (mM), temperature (°C), and time (minutes) by using response surface methodologies (RSM). Response surface models were applied by both BBD and CCD for determining optimal condition by maximizing the absorbance value. Results showed that both BBD and CCD models depicted the quadratic models with high regression coefficient of 0.9889 and 0.9448, respectively. The optimum conditions attained for BBD model are 9.53 g/L, 61.3 °C, 10.7 minutes, 1.22 mM with 1.000 desirability whereas 9.57 g/L, 60.5 °C, 10.4 minutes, 1.16 mM with 0.914 desirability based on CCD model. The BBD model generated was more reliable, with a greater prediction of absorbance value (1.100) that was very close to the actual values however the CCD model predictions were less accurate (1.078) to the actual response. The predicted response for BBD model showed excellent agreement with the actual value with residual standard error of 0.30% followed by CCD model with residual standard error of 2.52%. Consequently, it was discovered that BBD model is highly accurate, and the values associated with each optimal condition are close enough to actual results. Among the variables investigated, the concentration of C. longa extract was found to be the most significant element impacting absorbance value whereas the incubation time is least significant parameter influencing the absorbance value for both BBD and CCD model.
Comparison of different rsm designs to predict and optimize the acid violet (av 7) adsorption using rha-cfa adsorbent
(2021-06-01)
Mohamad, Ahmad Aqil Asyraaf
In this study, the factors affecting the performance of rice husk ash (RHA)-coal fly ash (CFA) adsorbent in removing acid violet 7 (AV7) dye were analysed using different type of response surface methodology (RSM). Face-Centered Composite Design, D-Optimal Design and Historical Data Design were compared based on the R2 value, Mean Square Error (MSE) and error in optimization section (%). DOD had the highest accuracy (R2 = 0.9765) in predicting dye adsorption efficiency, while FCC and HDD have lower accuracy but still in good value range (R2= 0.9335). By using Expert Design software, the optimum RHA-CFA adsorbent preparation condition with the highest AV7 dye adsorption efficiency was obtained through the numerical optimization of RSM models. Optimization by FCC and HDD, maximum adsorption efficiency obtained were 45.1% and DOD was 44.4% with RHA/CFA ratio of 3.00 and 1.00 M of NaOH. An additional experiment of RHA/CFA ratio of 3.00 and 1.00 M of NaOH is obtained from the literature and the result from it is used to compare with predicted values of each RSM design. DOD had the lowest error at value of 2.93% and both FCC and HDD models were 4.43%.
Conceptual study of enzymatic sugar ester synthesis in the pbr at steady-state and isothermal conditions
(2021-07-01)
Mohamed Firaz, Mohamed Zarif Wazif
Lipase was used widely in the production of sugar ester especially in food processing which used PBR as the reactor. The amount of yield produce is affected by the enzymatic activity which also effected by binding energy, temperature and amount of concentration of the substrate used. Ideal parameters based on experimental and also simulation path are the major problem in order to produce higher amount of sugar esters. The equation used for simulation were obtained based on the design equation for PBR and based on the two substrate reaction(Varde & Fogler, 2001). Two parameters were compared to obtain an optimum yield of sugar ester which are the temperature and the molar ratio of substrate. This parameters are validate and compared between the results obtained from Sebatini experiment in the literature with the simulation by using POLYMATH. From the comparison, Simulation result are much more accurate based on the validation of R2 methods as it can improve the data that used by the experimental. In agreement with Harwell and Co-workers, The result that obtained by the experimental can be modify by using the simulation methods (Harwell et al., 2017). The trend of the graph for the effect of temperature against yield of sugar ester shows the similar shape which the yield obtained was the highest at 40 ⁰C but slightly different for the effect of substrate concentration molar ratio against yield of sugar ester as the as it stated that the molar ratio of sugar: fatty acid for simulation should be 1:1 while for the experimental was 1:2 respectively. After obtaining the optimum and ideal parameters and constant for the sugar ester based on the comparison of both sources, the effect of kinetic parameter and thermodynamic parameter were discussed. From what obtained in kinetic parameter, the higher activation energy of substrate bind to enzyme and the lower the inhibition activation energy will increase rate of reaction. While for the thermodynamic parameters, the higher the activation energy of catalysis process, △Gcat, activation energy during equilibrium, △Heq and equilibrium temperature, Teq and the lower the activation energy of thermal inactivation process, △Ginact, will yield lower rate of reaction. This shows that the enzyme can act ideally if the activation energy of substrate binding higher while the inhibition activation energy is lower. Beside that, enzyme also can act ideally if the activation energy of catalysis, activation energy during equilibrium, and equilibrium temperature are lower while if the activation energy of thermal inactivation process is higher.
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.
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.
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.

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