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Effect of stirring time on synthesis of ultra fine α-Al2O3 powder by a simple sol-gel method
F. Mirjalili,Luqman Chuah,Hasmaliza Mohamad 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.6
The present paper tends to explore the effect of stirring time on the synthesis of nano α-Al2O3 particles. In this study, alumina nanoparticles were synthesized through an alkoxide route implementing sol-gel method in which aqueous solutions of aluminum isopropoxide and 0.5M aluminum nitrate nanohydrate were used to prepare an alumina sol. Sodium dodecylbenzen sulfonate was used as the surfactant stabilizing agent. The prepared solution was stirred for different times (24, 36, 48 and 60 hours)at 60 oC. The samples were, then, characterized by Brunauer-Emmet-Teller method, X-ray diffraction, thermogravimetry analysis,differential scanning calorimetry, Fourier transform infrared spectrometry , scanning electron microscopy and transmission electron microscopy. The introduction of different stirring times affected the particle size and shape and the degree of aggregation. By increasing the stirring time (starting from 24 to 48 hours), the particle size decreased, but there was a harder agglomeration for the samples with 60 hours stirring time. The finest particle size (20-30 nm) was obtained at 48 hours stirring time.
Xiaoju Li,Luqman Chuah Abdullah,Shafreeza Sobri,Mohamad Syazarudin Md Said,Siti Aslina Hussain,Tan Poh Aun,Jinzhao Hu 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.4
The air pollution process and impact mechanism of megacities located in complex terrain are particularly complex. As a typical megacity in China, Chengdu has unique topographical and meteorological conditions, and its pollution control is difficult. This study systematically elucidated the variation characteristics of six criteria air pollutants in Chengdu between 2014 and 2020. Besides, the PM<SUB>2.5</SUB>/PM<SUB>10 </SUB>and NO₂/SO₂ ratios were discussed. Furthermore, a detailed analysis of the correlation between air pollutants was carried out. Finally, the collaborative path of carbon reduction and air pollution control is discussed. The results indicated that SO₂, PM<SUB>2.5</SUB>, PM<SUB>10</SUB> and CO were significantly decreased by 62.9%, 50.8%, 45.5%, and 36.7%, respectively. PM2.5 and O3 compliance rates are very low, and O₃ increases with fluctuations. SO₂, NO₂, CO, PM showed a “U-shaped” seasonal variation, and there was a “seesaw” phenomenon between O₃ and PM2.5. The continuous changing trends also found in the ratios of PM<SUB>2.5</SUB>/PM<SUB>10</SUB> and NO₂/SO₂. The results highlight the importance of coordinated reduction of carbon emissions and pollutants in Chengdu. This research can improve the prediction accuracy of air pollution in complex terrain areas under global warming, and improve the understanding of the formation mechanism of air pollution in special terrains around the world.
Abel Adekanmi Adeyi,Nathan Kura Bitrus,Luqman Chuah Abdullah,Lekan Taofeek Popoola,Maureen Chijioke-Okere,Oluwagbenga Olawale Omotara,Shihab Ezzuldin M.Saber 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.1
Manganese dioxide was laden hooked on biochar sourced from chicken feather to obtain a biochar-supported manganese dioxide (BSM) composite. In order to reduce the costs of acquisition and minimise the disposal of adsorbents, prepared BSM composite were employed in the sequestration of Levofloxacin (LEVO) from aqueous environment. The physico-chemical features and the adsorption mechanisms of prepared BSM, prior and after the adsorption of LEVO molecules were revealed by Scanning Electron Microscopy and Fourier Transform Infrared spectroscopy techniques. The influence of adsorption parameters including BSM dose, initial concentration, temperature and residence time were studied. The removal of LEVO was significantly influenced by all parameters. Equilibrium data has its fitness in the following order: Redlich-Peterson ˃ Langmuir ˃ Freundlich models. The maximum adsorption capacity of BSM for LEVO was 104.13 mg/g. The kinetic analysis indicates best fittings for pseudo-second-order model suggesting chemisorption as controlled mechanism. Besides, liquid film and intra-particle diffusion had a vital influence on the LEVO sequestration process. Exothermic and spontaneous nature of LEVO uptake by BSM was revealed by thermodynamic analysis. The findings suggested that prepared BSM show high sorption capacity, and recyclability potential towards separation of LEVO from contaminated pharmaceutical wastewater.
Mohamad Rasool Malekbala,Moonis Ali Khan,Soraya Hosseini,Luqman Chuah Abdullah,Thomas S.Y. Choong 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
Surfactant modified carbon coated monolith was used as an adsorbent for methylene blue (MB)adsorption. Effects of pH, salt, contact time, initial dye concentrations and temperature on dyeadsorption were studied. Higher solution pH favoured MB adsorption. Furthermore, kinetics studyshowed that the adsorption could be better represented by the pseudo-second-order model. Linear andnon-linear isotherm studies revealed better fitting of Langmuir model to adsorption data with maximummonolayer adsorption capacity 388 mg/g. The adsorption was found to be spontaneous andendothermic. Desorption studies indicate that 0.1 N HCl exhibits higher elution efficiency (82.1%) withappreciable quantitative MB recovery.
Lau Kia Li,Siti Nurul Ain Md. Jamil,Luqman Chuah Abdullah,Nik Nor Liyana Nik Ibrahim,Adeyi Abel Adekanmi,Mohsen Nourouzi 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.6
This research reports application of artificial neural network (ANN) in investigation and optimisation of boron adsorption capacity in aqueous solution using amidoxime-modified poly(acrylonitrile-co-acrylic acid) (AO-modified poly(AN-co-AA)). Both feed-forward and recurrent ANN have been utilized to predict the adsorption potential of synthesised polymer. Three operational parameters, which are adsorbent dosage, initial pH and initial boron concentration during adsorption process were designed to study their effects on the removal capacity. The ANN was trained from experimental data and serviced to optimize, develop and create various prediction models in the process of boron adsorption by AO-modified poly(AN-co-AA). Among several models, radial basis function (RBF) with orthogonal least square (OLS) algorithm displayed good prediction on boron adsorption capacity with mean square error (MSE) and coefficient of determination (R²) at 0.000209 and 0.9985, respectively. With desirable the MSE and R² values, ANN worked as a promising prediction tool that was able to generate good estimate. The simulated maximum adsorption capacity of the synthesized polymer is 15.23 ± 1.05 mg boron/g adsorbent. Besides, from the results of ANN, the AO-modified poly(AN-co-AA) was proven to be a potential adsorbent for the removal of boron in wastewater treatment.