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.
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 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.
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.
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.
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.
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.
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.
Synthesis of butyl acetate by lipase-catalysed esterification
(2021-06-01)
Sim, Wan Ting
Ester is an aromatic compound naturally found in plants and fruits, which is an important additive for food, beverages, pharmaceutical and cosmetic industries, giving flavour and fragrance. The compound is either supplied by natural resources or chemical synthesis. Lipase as biocatalyst shows great potential in aroma ester synthesis since lipase-catalysed reaction product is verified to be natural. In this study, butyl acetate was synthesised from acetic acid and n-butanol esterification catalysed by immobilized Candida rugosa lipase. The process parameters which were optimized included reaction time, enzyme amount, temperature, and acetic acid/ethanol molar ratio were studied using one-factor-at-a-time (OFAT) method. Optimal molar conversion for butyl acetate of 81.33 % was obtained at 40 minutes incubation time with 50 U/ml of enzyme amount and substrate molar ratio of 1:1 (0.1 M) at 40 ℃ and 150 rpm. The kinetic parameters were also calculated using secondary data extracted from another researcher group. The data was fitted into Random Bi Bi, Ordered Bi Bi and Ping Pong Bi Bi mechanisms to compare the kinetic parameters obtained. The kinetic analysis of the esterification reactions was found to follow a Ping Pong Bi Bi mechanism with inhibition by one of the substrates, acetic acid. The fitted kinetic parameters obtained were Vmax = 249.05 mol/min.g, K m(A) = 46.25 mol/dm3, K m(B) = 4.15 mol/dm3, KI = 15.09 mol/dm3.
Feasibility of screen printing carbon electrode to detect ascorbic acid
(2021-06-01)
Bohiran, Muhammad Fahim Azim
Screen-printed carbon electrodes (SPCE) used for electrochemical detection consist of three electrodes: auxiliary, working, and reference electrode. The working electrode is the principal electrode on which electrochemical reactions are performed, while the reference and auxiliary electrodes are used to complete the electronic circuit. The effect of varying the working electrode conductive ink thickness (2, 3, 4, 5, and 7 layers of SPCE) on the final electrochemical activity was investigated in this study. The depth of SPCE been submerged in 20mL of analyte is fixed at 1.5 cm since the exact length is unknown. It shows that by increasing the layer of conductive ink thickness, the oxidation peak is increasing too. Four-layer SPCE gives the optimum results for detection of AA at a concentration of 3mM to 10mM with the R2 value is almost 0.99. Besides, this report also investigates the selection of ascorbic acid (AA) from citric acid (CA) by using the four-layer SPCE.
Observing the parameter dependant system on the formation of lag phase curve in a bacteria growth
(2021-06-01)
Chang, Chee Wing
Predictive biology plays an important in forecasting the behaviour of the microorganism under the unpredictable environment condition such as temperature and pH. In order to precisely simulate the growth of the microorganism, several growth models had been proposed. Logistic model, modified Gompertz equation, Luedeking-Piret model and Monod model are the models that were studied in this work. These models composed of several growth parameters which have significant impact on the growth curve. Typically, growth curves are presented in the form of sigmoidal curve. Growth parameters such as maximum specific growth rate (µmax) and lag time (𝜆) can be affected by the environment condition. In this work, the effect of the variation of the growth parameters on the formation of sigmoidal curve especially the duration of lag phase had been studied. Simulation of this work was carried out using MATLAB® and data collection by Microsoft Excel®. Higher value of maximum specific growth rate (µmax) in Logistic model and Monod model shorten the duration of lag phase while the µmax in modified Gompertz model has no effect on the duration of lag phase but make the slope of the exponential phase steeper. Besides, higher yield coefficient (Ys) is found to that not only increase the yield concentration but also increase the duration of lag phase.
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.
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.
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.
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%.
Simulation study of biodiesel production via transesterification process from waste cooking oil
(2021-06-01)
Mohamad, Nurul Hazirah
Biodiesel is an environmental-friendly and alternative liquid fuel that can be used to substitute conventional diesel. It can be produced by a variety of feed stocks such as animal fats, non-edible oils and by-product of the refining vegetable oils. Biodiesel becomes a spotlight as a renewable fuel that is non-toxic and is biodegradable. It is usually synthesised by the transesterification of vegetable oil or animal fat with short chain alcohol such as methanol or ethanol. Its high oxygen content makes it a better choice for diesel engines. Waste cooking oil is one of the feedstocks that can be converted into biodiesel. Therefore, in this simulation study, waste cooking oil has been used as the raw material that reacted with methanol. This study was done by using Matlab software to observe how the operating conditions affect on the yield, conversion and selectivity of biodiesel. It was found that the temperature of 60 ̊C exhibited the highest yield of methyl ester. Oil to alcohol ratio of 1:15 gives the highest yield at 59%and catalyst weight of 1.4 wt % leads to the maximum yield of biodiesel. The simulation results obtained reasonable with the literature results and within the range studied by the previous researchers.
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.
Microwave irradiated rice husk based activated carbon for adsorption of chloramphenicol
(2021-06-01)
Mohd Shah, Izlan
Pharmaceutical industry was one of the main contributors of Chloramphenicol (CAP) to the water sources which can causes various environmental problems. In recent years, agriculture waste based activated carbon has been employed as an adsorbent in the treatment of antibiotics wastewater. The purpose of this study is to investigate the performance of activated carbon (AC) generated from rice husk (RH) for the removal of Chloramphenicol (CAP) by physical activation utilizing carbon dioxide (CO2) gasification and microwave irradiation technique. Response Surface Methodology (RSM) was used to optimize the rice husk based activated carbon’s(RHAC) preparation parameters of radiation power and activation time for adsorption of Chloramphenicol (CAP). The optimum conditions for RHAC preparation were observed to be 490 W of radiation power and 2 minutes of activation time which resulted 92.15% of CAP removal and 65.43% of RHAC’s yield. The CAP adsorption by RHAC increased as the initial CAP concentration and contact time increased. Adsorption equilibrium of CAP onto RHAC followed Freundlich isotherm. The kinetic studies of CAP adsorption onto RHAC was best represented by pseudo-second order kinetic models. According to the thermodynamic analysis, the value of ∆H° was negative, indicating that the adsorption was an exothermic process.

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