Sonocatalytic removal of ibuprofen and sulfamethoxazole in the presence of different fly ash sources

Al-Hamadani, Yasir A.J.,Park, Chang Min,Assi, Lateef N.,Chu, Kyoung Hoon,Hoque, Shamia,Jang, Min,Yoon, Yeomin,Ziehl, Paul Elsevier 2017 Ultrasonics sonochemistry Vol.39 No.-

<P><B>Abstract</B></P> <P>We examined the feasibility of using two types of fly ash (an industrial waste from thermal power plants) as a low-cost catalyst to enhance the ultrasonic (US) degradation of ibuprofen (IBP) and sulfamethoxazole (SMX). Two fly ashes, Belews Creek fly ash (BFA), from a power station in North Carolina, and Wateree Station fly ash (WFA), from a power station in South Carolina, were used. The results showed that >99% removal of IBP and SMX was achieved within 30 and 60min of sonication, respectively, at 580kHz and pH 3.5. Furthermore, the removal of IBP and SMX achieved, in terms of frequency, was in the order 580kHz>1000kHz>28kHz, and in terms of pH, was in the order of pH 3.5>pH 7>pH 9.5. WFA showed significant enhancement in the removal of IBP and SMX, which reached >99% removal within 20 and 50min, respectively, at 580kHz and pH 3.5. This was presumably because WFA contains more silicon dioxide than BFA, which can enhance the formation of OH<SUP> </SUP> radicals during sonication. Additionally, WFA has finer particles than BFA, which can increase the adsorption capacity in removing IBP and SMX. The sonocatalytic degradation of IBP and SMX fitted pseudo first-order rate kinetics and the synergistic indices of all the reactions were determined to compare the efficiency of the fly ashes. Overall, the findings have showed that WFA combined with US has potential for treating organic pollutants, such as IBP and SMX, in water and wastewater.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sonocatalytical degradation of ibuprofen and sulfamethoxazole was investigated. </LI> <LI> Effect of pH and frequency on the degradation was studied. </LI> <LI> In the presence of fly ashes, >99% removal of IBP and SMX was achieved at 580kHz and pH 3.5. </LI> </UL> </P>

Stabilization and dispersion of carbon nanomaterials in aqueous solutions: A review

Al-Hamadani, Yasir A.J.,Chu, Kyoung Hoon,Son, Ahjeong,Heo, Jiyong,Her, Namguk,Jang, Min,Park, Chang Min,Yoon, Yeomin Elsevier Science B.V., Amsterdam. 2015 Separation and purification technology Vol.156 No.-

Sonocatalytical degradation enhancement for ibuprofen and sulfamethoxazole in the presence of glass beads and single-walled carbon nanotubes

Al-Hamadani, Y.A.J.,Chu, K.H.,Flora, J.R.V.,Kim, D.H.,Jang, M.,Sohn, J.,Joo, W.,Yoon, Y. Elsevier Science 2016 Ultrasonics sonochemistry Vol.32 No.-

Sonocatalytic degradation experiments were carried out to determine the effects of glass beads (GBs) and single-walled carbon nanotubes (SWNTs) on ibuprofen (IBP) and sulfamethoxazole (SMX) removal using low and high ultrasonic frequencies (28 and 1000kHz). In the absence of catalysts, the sonochemical degradation at pH 7, optimum power of 0.18WmL<SUP>-1</SUP>, and a temperature of 15<SUP>o</SUP>C was higher (79% and 72%) at 1000kHz than at 28kHz (45% and 33%) for IBP and SMX, respectively. At the low frequency (28kHz) H<SUB>2</SUB>O<SUB>2</SUB> production increased significantly, from 10μM (no GBs) to 86μM in the presence of GBs (0.1mm, 10gL<SUP>-1</SUP>); however, no enhancement was achieved at 1000kHz. In contrast, the H<SUB>2</SUB>O<SUB>2</SUB> production increased from 10μM (no SWNTs) to 31μM at 28kHz and from 82μM (no SWNTs) to 111μM at 1000kHz in the presence of SWNTs (45mgL<SUP>-1</SUP>). Thus, maximum removals of IBP and SMX were obtained in the presence of a combination of GBs and SWNTs at the low frequency (94% and 88%) for 60min contact time; however, >99% and 97% removals were achieved for 40 and 60min contact times at the high frequency for IBP and SMX, respectively. The results indicate that both IBP and SMX degradation followed pseudo-first-order kinetics. Additionally, the enhanced removal of IBP and SMX in the presence of catalysts was because GBs and SWNTs increased the number of free OH<SUP>?</SUP> radicals due to ultrasonic irradiation and the adsorption capacity increase with SWNT dispersion.

Sonocatalytic degradation of carbamazepine and diclofenac in the presence of graphene oxides in aqueous solution

Al-Hamadani, Yasir A.J.,Lee, Gooyong,Kim, Sewoon,Park, Chang Min,Jang, Min,Her, Namguk,Han, Jonghun,Kim, Do-Hyung,Yoon, Yeomin Elsevier 2018 CHEMOSPHERE - Vol.205 No.-

<P><B>Abstract</B></P> <P>This research investigated the removal of carbamazepine (CBZ) and diclofenac (DCF) in water using ultrasonic (US) treatment in the absence or presence of graphene oxides (GOs). Three frequencies and three pH conditions were tested (28, 580, and 1000 kHz and 3.5, 7, and 9.5, respectively). Regarding the effects of US frequency and pH, 580 kHz and pH 3.5 were more effective at removing CBZ and DCF (>86% for CBZ and >92% for DCF) than 1000/28 kHz and pH 7/9.5 within 60 min. However, sonocatalytic removal was enhanced in the presence of GOs; more than 99% CBZ and DCF removal was achieved at 580 kHz and pH 3.5 within 40 min. The sonicated GOs were more stable at 28 kHz than at higher frequencies of 580 and 10,00 kHz. The adsorption of CBZ and DCF has increased when GOs were sonicated at 28 kHz (44% and 61%, respectively) compared with 580 kHz (34% and 52%, respectively) and 1000 kHz (18% and 39%, respectively). The negative charges of GOs increased at 28 kHz (−105.1 mV), however, it decreased at higher frequencies such as 580 kHz (−71.5 mV) and 1000 kHz (−58.6 mV), which led to increased electrostatic repulsion that increased the stability of the GO particles in water. The overall enhancement in CBZ and DCF removal was due to an increase in cavitational bubbles, which in turn led to increased production of OH<SUP>•</SUP> and enhanced adsorption due to dispersion (resulting from US irradiation), which caused an increase in active adsorption sites of the GOs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sonocatalytic degradation of carbamazepine and diclofenac under different pH and frequency conditions was studied. </LI> <LI> Enhancement in the sonodegradation of carbamazepine and diclofenac was achieved in the presence of graphene oxides. </LI> <LI> The stability and adsorption of graphene oxides at different frequency conditions were evaluated. </LI> </UL> </P>

System Dynamic Modelling of Three Different Wind Turbine Gearbox Designs under Transient Loading Conditions

Haider Al-Hamadani,Taylan An,Matthew King,Hui Long 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.11

Wind turbine (WT) drivetrain design configurations affect dynamic loads experienced by the drivetrain components under different operational conditions. This paper presents system modelling of dynamic loads experienced by key mechanical components within WT gearbox under different operational conditions by using MATLAB/Simulink. Two operational conditions of WTs are considered; normal operation and shutdown, using torque spectrums measured from a field operating wind turbine. The torsional dynamic loads under these conditions differ significantly; during normal operation, the maximum torque ratio is below the recommend value however it exceeds the recommended level during shutdown. It has been found that the shutdown event has a considerable effect on gear loading; it causes occurrences of loading reversal of gear meshing forces. Moreover, the variation range of meshing forces between planetary and sun gears is five to six times higher than that during normal operation. During shutdown, the most dominated vibration frequency of the WT drivetrains is the lowest one which is very close to the estimated natural frequency of the low speed shaft and that may cause the resonance of the drivetrain system.

Evaluation of biochar-ultrafiltration membrane processes for humic acid removal under various hydrodynamic, pH, ionic strength, and pressure conditions

Shankar, Vaibhavi,Heo, Jiyong,Al-Hamadani, Yasir A.J.,Park, Chang Min,Chu, Kyoung Hoon,Yoon, Yeomin Academic Press 2017 Journal of Environmental Management Vol. No.

<P>The performance of an ultrafiltration (UF)-biochar process was evaluated in comparison with a UF membrane process for the removal of humic acid (HA). Bench-scale UF experiments were conducted to study the rejection and flux trends under various hydrodynamic, pH, ionic strength, and pressure conditions. The resistance-in-series model was used to evaluate the processes and it showed that unlike stirred conditions, where low fouling resistance was observed (28.7 x 10(12) m(-1) to 32.5 x 10(12) m(-1)), higher values and comparable trends were obtained for UF-biochar and UF alone for unstirred conditions (28.7 x 10(12) m(-1) to 32.5 x 10(12) m(-1)). Thus, the processes were further evaluated under unstirred conditions. Additionally, total fouling resistance was decreased in the presence of biochar by 6%, indicating that HA adsorption by biochar could diminish adsorption fouling on the UF membrane and thus improve the efficiency of the UF-biochar process. The rejection trends of UF-biochar and UF alone were similar in most cases, whereas UF-biochar showed a noticeable increase in flux of around 18-25% under various experimental conditions due to reduced membrane fouling. Three-cycle filtration tests further demonstrated that UF-biochar showed better membrane recovery and antifouling capability by showing more HA rejection (3-5%) than UF membrane alone with each subsequent cycle of filtration. As a result of these findings, the UF-biochar process may potentially prove be a viable treatment option for the removal of HA from water. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Aggregation kinetics of single walled carbon nanotubes influenced by the frequency of ultrasound irradiation in the aquatic environment

Min Park, Chang,Al-Hamadani, Yasir A.J.,Heo, Jiyong,Her, Namguk,Hoon Chu, Kyoung,Jang, Min,Lee, Sangho,Yoon, Yeomin Elsevier 2017 Ultrasonics sonochemistry Vol.39 No.-

<P><B>Abstract</B></P> <P>The colloidal stability of single-walled carbon nanotubes (SWNTs) sonicated at three different ultrasonication (US) frequencies (28, 580, and 1000kHz) were investigated under environmentally relevant conditions. In particular, correlations between surface chemistry, electrokinetic potential, interaction energy, and the aggregation kinetics of the aqueous SWNTs were studied. We observed that H<SUB>2</SUB>O<SUB>2</SUB> production is negatively correlated with the yield of hydroxylation and carboxylation of SWNTs, which was dependent on the generation of ultrasonic energy by cavity collapse during US process. The SWNTs sonicated at relatively high US frequencies (580 and 1000kHz) aggregated rapidly in synthetic surface water, whereas alkalinity affected the stability of SWNTs insignificantly. This was because the SWNTs became less negatively charged under such conditions and were captured in deep primary energy wells, according to the Derjaguin-Landau-Verwey-Overbeek theory. Critical coagulation concentration values for the ultrasonicated SWNTs were determined to be 102mM NaCl for 28kHz, 22mM NaCl for 580kHz, and 43mM NaCl for 1000kHz. Suwannee River humic acid decreased the aggregation rate of SWNTs due to the steric hindrance, because of adsorbed macromolecules. Our findings show that the aggregate stability of SWNTs is controlled largely by a complex interplay between the evolution of surface functional groups on the SWNTs during US and solution chemistry.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Aggregation of SWNTs was investigated as a function of sonication frequency. </LI> <LI> SWNTs sonicated at high US frequencies aggregated rapidly in SSW. </LI> <LI> SRHA decreased aggregation rate of SWNTs due to the steric hindrance. </LI> </UL> </P>

Ultrasonic treatment of endocrine disrupting compounds, pharmaceuticals, and personal care products in water: A review

Chu, Kyoung Hoon,Al-Hamadani, Yasir A.J.,Park, Chang Min,Lee, Gooyong,Jang, Min,Jang, Am,Her, Namguk,Son, Ahjeong,Yoon, Yeomin Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.327 No.-

<P><B>Abstract</B></P> <P>The presence of contaminants of emerging concerns such as endocrine-disrupting compounds (EDCs) and pharmaceuticals/personal-care products (PPCPs) is of concern because they are not completely removed during conventional water and wastewater (WW) treatment processes including coagulation/flocculation/sedimentation/filtration and biological activated sludge process. Recently, ultrasonic (US) treatment has been well-known as an advanced treatment process for the removal of complex inorganic and organic contaminants in water and WW. US treatment has shown substantial advantages, such as cleanliness, safety, energy savings, and negligible or no secondary pollution products. This review provides a summary of recent research on the removal of EDCs and PPCPs by US treatment and also provides information valuable for applications of US treatment in water and WW treatment. The removal of numerous EDCs and PPCPs of different classes was reviewed based on the current literature to (i) address key factors (water quality conditions (pH, temperature, background common ions, and promoters/scavengers), US frequency, power, and reactor type) influencing the sonodegradation of EDCs and PPCPs and their intermediates during US treatment, (ii) evaluate the effects of various catalysts and hybrid processes on sonodegradation, and (iii) discuss EDC and PPCP removal according to their properties. Additionally, areas of future research in US treatment for the removal of EDCs and PPCPs from water are suggested.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Removal of contaminants of emerging concerns in water was reviewed. </LI> <LI> Valuable information was provided for applications of ultrasonication in water treatment. </LI> <LI> Areas of future research for the removal of contaminants of emerging concerns are suggested. </LI> </UL> </P>

Fabrication of graphene-oxide/β-Bi₂O₃/TiO₂/Bi₂Ti₂O₇ heterojuncted nanocomposite and its sonocatalytic degradation for selected pharmaceuticals

Lee, Gooyong,Chu, Kyoung Hoon,Al-Hamadani, Yasir A.J.,Park, Chang Min,Jang, Min,Heo, Jiyong,Her, Namguk,Kim, Do-Hyung,Yoon, Yeomin Elsevier 2018 CHEMOSPHERE - Vol.212 No.-

<P><B>Abstract</B></P> <P>A graphene-oxide (GO)/β-Bi<SUB>2</SUB>O<SUB>3</SUB>/TiO<SUB>2</SUB>/Bi<SUB>2</SUB>Ti<SUB>2</SUB>O<SUB>7</SUB> heterojuncted nanocomposite, designated as GBT, was synthesized via a two-step hydrothermal process. The sonocatalytic activity of the GBT was evaluated at several frequencies (28, 580, and 970 kHz) and compared with Bi-doped GO (GB) and Ti-doped GO (GT). Transmission electron microscopy images showed heterojuncted crystal structures of Bi and Ti on GO, and X-ray diffraction patterns verified that the crystal structures consisted of β-Bi<SUB>2</SUB>O<SUB>3</SUB>, TiO<SUB>2</SUB>, and Bi<SUB>2</SUB>Ti<SUB>2</SUB>O<SUB>7</SUB> nanocomposites. Energy-dispersive X-ray spectroscopy revealed a higher proportion of metal on GBT surfaces compared with GB and GT surfaces. The energy band gaps of GT, GB, and GBT were 3.0, 2.8, and 2.5 eV, respectively. Two pharmaceuticals (PhACs; carbamazepine [CBZ] and acetaminophen [ACE]) were selected and treated under sonolytic conditions at frequencies of 28, 580, and 970 kHz at a power level of 180 W L<SUP>−1</SUP>. The selected pharmaceuticals, present at initial concentrations of 20 μM, were reduced by over 99% by ultrasonic irradiation in the presence of GBT. The 580 kHz treatment achieved the most rapid organic removal among the frequencies tested. The removal kinetic of CBZ was higher than that of ACE owing to its relatively high hydrophobicity. High sonocatalytic activity of GBT was observed through measurement of H<SUB>2</SUB>O<SUB>2</SUB> in solution. Because of its low band gaps and high surface activity, GBT exhibited higher sonolytic activity in removing selected PhACs than GT or GB.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new heterojuncted sonocatalyst (GBT = graphene oxide/β-Bi<SUB>2</SUB>O<SUB>3</SUB>/TiO<SUB>2</SUB>/Bi<SUB>2</SUB>Ti<SUB>2</SUB>O<SUB>7</SUB>) was synthesized. </LI> <LI> GBT showed higher sonocatalytic activity than Tie or Bi-doped graphene oxide. </LI> <LI> Two target pharmaceuticals were successfully degraded under sonolysis in the presence of GBT. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Influence of solution pH, ionic strength, and humic acid on cadmium adsorption onto activated biochar: Experiment and modeling

박창민,한종훈,추경훈,Yasir A.J. Al-Hamadani,허남국,허지용,윤여민 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.48 No.-

Biochar was prepared by pyrolysis of torrefied loblolly pine and used as a sorbent for the removal of Cd(II)ions from aqueous solutions. The effects of pH, ionic strength, and humic acid (HA) on Cd(II) adsorptionon biochar were investigated in comparison with other sorbents, commercially available powderedactivated carbon (PAC) and multi-walled carbon nanotubes (MWNT). The order of overall adsorption forCd(II) was biochar > PAC > MWNT for the adsorbents. In addition, the results indicated that the sorptionbehaviors of Cd(II) were strongly dependent on pH and ionic strength. The maximum adsorption capacityof Cd(II) on biochar at pH 7.5 0.1 and T = 25 C was calculated to be 167.3 mg/g, much higher than otherreports. The presence of HA modifies the surface properties of biochar and enhances complexation of Cd(II) with adsorbed HA. Surface complexation modeling gave an excellentfit with the predominantmononuclear monodentate >SOCd2+ in the absence of HA and the ternary surface >SOL1Cd species in thepresence of HA as well as binuclear bidentate >(SO)2Cd species at higher pH. The results of this studyhighlight that biochar is a suitable material for the removal of environmental cadmium pollution.