Faculty Publications

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    Acetaminophen micropollutant: Historical and current occurrences, toxicity, removal strategies and transformation pathways in different environments
    (Elsevier Ltd, 2019) Vo, H.N.; Le, G.K.; Nguyen, T.M.; Bui, X.-T.; Nguyen, K.H.; Rene, E.R.; Vo, T.D.H.; Cao Ngoc, N.-D.; Mohan, R.
    Acetaminophen (ACT) is commonly used as a counter painkiller and nowadays, it is increasingly present in the natural water environment. Although its concentrations are usually at the ppt to ppm levels, ACT can transform into various intermediates depending on the environmental conditions. Due to the complexity of the ACT degradation products and the intermediates, it poses a major challenge for monitoring, detection and to propose adequate treatment technologies. The main objectives of this review study were to assess (i) the occurrences and toxicities, (2) the removal technologies and (3) the transformation pathways and intermediates of ACT in four environmental compartments namely wastewater, surface water, ground water, and soil/sediments. Based on the review, it was observed that the ACT concentrations in wastewater can reach up to several hundreds of ppb. Amongst the different countries, China and the USA showed the highest ACT concentration in wastewater (?300 ?g/L), with a very high detection frequency (81–100%). Concerning surface water, the ACT concentrations were found to be at the ppt level. Some regions in France, Spain, Germany, Korea, USA, and UK comply with the recommended ACT concentration for drinking water (71 ng/L). Notably, ACT can transform and degrade into various metabolites such as aromatic derivatives or organic acids. Some of them (e.g., hydroquinone and benzoquinone) are toxic to human and other life forms. Thus, in water and wastewater treatment plants, tertiary treatment systems such as advanced oxidation, membrane separation, and hybrid processes should be used to remove the toxic metabolites of ACT. © 2019 Elsevier Ltd
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    Cobalt ferrite nanoparticles and peroxymonosulfate system for the removal of ampicillin from aqueous solution
    (Elsevier Ltd, 2021) Mohan Balakrishnan, R.M.; Ilango, I.; Gamana, G.; Bui, X.-T.; Arivalagan, A.
    Emerging contaminants (EC) are classified as major leading issues in treating wastewater, especially drugs and pharmaceuticals in the urban regions, and the detection and degradation of these pollutants have become an arduous task. Ampicillin is one such portentous ?- lactam antibiotic compound used extensively in the medical field for their antimicrobial and growth-enhancing properties in humans as well in veterinary sectors. Due to continuous exposure, the microbes in due course developed a shield towards the implication of antibiotics. The degradation of Ampicillin has also been succeeded by mixed metal oxides nanoparticles generally specified as AxB2-xO4, which has been a fundamental catalyst in the Advanced Oxidation Process (AOPs). Magnetic nanoparticles, Cobalt Ferrite nanoparticles (CoFe2O4) were synthesized by the coprecipitation method further; it has employed in the activation of oxidizing agent Peroxymonosulfate (PMS) in the Ampicillin degradation. The material and chemical characterization of synthesized nanoparticles using XRD, TEM, SEM-EDX, and FTIR analysis were done. From the investigation, the nanoparticles were found to exhibit a cubic spinel configuration with a crystallite size of 10.10 nm. The impact of working parameters, such as the presence/absence of catalyst, pH, PMS concentration, and the time required for ampicillin degradation, were investigated. At neutral pH with 0.1 g/L of catalyst measure, 0.2 mM of PMS, 90 ± 1.94 % Ampicillin degraded over 25 min of contact time. The degraded intermediate products of Ampicillin were identified using LC–MS analysis. © 2020 Elsevier Ltd
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    Functionalization of β-cyclodextrin onto NiFe2O4 nanoparticles for the removal of ketoprofen and diclofenac from the aqueous solutions
    (Institute for Ionics, 2024) Ilango, I.; Mohan Balakrishnan, R.M.; Visvanathan, C.; Bui, X.-T.; Velusamy, P.
    A new β-CD functionalized nickel ferrite nanocomposite was synthesized and used to remove pharmaceutical drugs, such as ketoprofen (KF) and diclofenac (DCF). The co-precipitation approach was utilised to synthesize nickel ferrite (NFO) nanoparticles, which were then functionalized with TEOS to form NFO@SiO2; β-cyclodextrin was then functionalized using GPTMS as an interface to form NFO@SiO2@β-CD. FTIR, ZD, FE-SEM, EDX, TGA/DTG, VSM, BET, zeta potential and particle size analysis were then used to characterise the nanocomposites. The NFO@SiO2@β-CD has an average diameter of 109.1 nm, superparamagnetic behaviour, a mesoporous surface and a specific surface of 20.78 m2/g. The functionalized NFO@SiO2@ β-CD nanocomposite removed 94% of diclofenac in 5 min and 80% of ketoprofen in 360 min with the adsorption capacities of 8.46 and 0.54 mg/g, respectively. The obtained experimental datum for both the pollutants was fitted in kinetic and isotherm models, with the pseudo-second-order kinetic model and Freundlich adsorption isotherm showing the best fit with the highest regression of R 2 = 0.99. The nanocomposite was regenerated using 0.1 M NaOH and recycled for about four consecutive cycles in which the reduction in the removal efficiency of ketoprofen and diclofenac was observed to be 51.36% and 64%, respectively. These results suggested that the NFO@SiO2@β-CD nanocomposite could be used specifically to target the low-concentrated pharmaceutical pollutants. Graphical Abstract: Schematic representation of Functionalization of β-Cyclodextrin onto NiFe2O4 nanoparticles for the removal of ketoprofen and diclofenac from the aqueous solutions. [Figure not available: see fulltext.] © 2023, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.
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    Stimulation of peroxymonosulfate using nickel ferrite nanoparticles for the degradation of Lomefloxacin hydrochloride and caffeine
    (Springer Science and Business Media Deutschland GmbH, 2025) Ilango, I.; Mohan Balakrishnan, R.; Visvanathan, C.; Bui, X.-T.
    Lomefloxacin Hydrochloride (LFH), an antibacterial agent, and caffeine (CAF), a cognitive enhancer, are excreted by humans and end up in municipal sewage effluents and surface waters. This pharmaceutical concentration in bodies of water/treatment plants poses a serious threat to both aquatic habitats and humans. A laboratory batch study on the degradation of LFH, CAF and LC (CAF and LFH mixed solution) was carried out using NFO nanoparticles to stimulate potassium peroxymonosulfate (PMS). The NFO nanoparticles were synthesized through a co-precipitation method and characterised using FTIR, XRD, FESEM/EDX, TGA/DTA/DTG, BET, AFM, VSM, and Zeta potential. The particle size distribution from FESEM (using ImageJ software) revealed that 83.3% of particles are ? 100 nm, its mean and standard deviation were estimated to be 43.87 nm and 20 to 25 nm. The NFO nanoparticles’ specific surface area was estimated to be 112.02 m2/g, and the magnetic properties of the NFO nanoparticles were investigated using VSM analysis. The parametric study included bare NFO, PMS without catalyst, pH, catalyst dosage, PMS variation with optimized catalyst, initial concentration of LFH and CAF, and reaction time, with nearly 94.34% LFH was degraded in 220 min, 100% CAF was degraded in 80 min, 78.07% LC was degraded in 40 min. The degraded compounds m/z of LFH, CAF and LC were identified using LC–MS. The recycling and regeneration of NFO nanoparticles were investigated to determine the stability of the NFO nanoparticles in the degradation of LFH and CAF in which the degradation efficiency decreased to 90.68% and 64.1% respectively upon the third wash with distilled water. As a result, the NiFe2O4/PMS system showed improved degradation even after three recycle runs, making it an efficient and economical system for degrading LFH, CAF and even to multi-pharmaceutical pollutants. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.