Institute for Mineral and Energy Resources publications
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Browsing Institute for Mineral and Energy Resources publications by Author "Badalyan, A."
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Item Metadata only An assessment of activated carbon cloth microporosity change due to chemical activation(Pergamon-Elsevier Science Ltd, 2010) Badalyan, A.; Bromball, R.; Pendleton, P.; Skinner, W.; Institute for Mineral and Energy ResourcesControlled modification of micropore volumes of samples from the FM1-series of activated carbon cloth can be achieved via selective oxidation: strong caustic treatment leads to an increase in volume, while peroxydisulfate treatment leads to a decrease in volume. Pore volume increases are determined to be due to inorganic content leaching, determined via XPS analyses, developing small primary micropores for the least activated carbon cloth (FM1/250) and a widening of the pore width for the most activated carbon cloth (FM1/700). All cloths exhibited Type I nitrogen adsorption isotherms both prior to and post oxidative treatment. © 2009 Elsevier Ltd. All rights reserved.Item Metadata only Analysis of uncertainties in manometric gas-adsorption measurements II: Uncertainty in alpha S-analyses and pore volumes(Academic Press Inc Elsevier Science, 2008) Badalyan, A.; Pendleton, P.; Institute for Mineral and Energy ResourcesWe describe procedures to propagate the uncertainty in adsorption data and alpha(S)-values to generate uncertainty in apparent primary, secondary, and total micropore volumes for porous activated carbons exhibiting Type I and IV character. The alpha(S)-data are interpolated from selected non-porous reference material (NPRM) adsorption isotherm data with some adsorbents exhibiting surface chemistry quite different from and some similar to that of the porous adsorbents (PA). We show that a statistically constant apparent total micropore volume can be determined independent of the NPRM surface chemistry. In contrast, NPRM surface chemistry appears to influence our ability to identify unequivocally the filling and condensation ranges of micropore filling, leading to statistically different apparent primary and secondary micropore volumes.Item Metadata only Assessment of chloramination control strategy based on free-ammonia concentration(IWA Publishing, 2009) Motzko, S.; Fabris, R.; Badalyan, A.; Henderson, R.; Chow, C.; Vitanage, D.; Institute for Mineral and Energy ResourcesA new approach of using free-ammonia measurements as the basis of a control strategy to optimise a chloraminated water distribution system was tested in a laboratory evaluation. A test rig with a newly developed low level on-line free-ammonia analyser was constructed to investigate two different control configurations, the currently used feedback and the proposed feedforward. The results of this trial showed that only using the free-ammonia analyser for feedback control is not ideal due to its inability to detect chlorine overdosing situations. Better results regarding the maximum yield of disinfectant residuals when using the feedforward configuration were observed, and free-ammonia concentrations below 0.065 mg/L were consistently achieved.Item Metadata only Effects of surface functional groups of activated carbon on adsorption of triclosan from aqueous solution(Inderscience Publishers, 2009) Fang, S.; Pendleton, P.; Badalyan, A.; Environmental Research Event (ERE) (10 Dec 2006 : Sydney)We report adsorption of triclosan by using activated carbons as a potential method to improve the discharge water purification process. Commercially available activated carbons, P1300, Picazine HP and Hydrodarco C, display different levels of affinity for triclosan from aqueous solution. Surface chemistry of these adsorbents were modified via reduction, oxidation and nitridation, to improve and better understand the adsorption process. The adsorption capacity was greatly influenced by surface group changes, with a decrease in relative affinity on oxidation. Nitridation enhanced the amounts adsorbed over the thermally reduced samples. Surface analysis via X-ray Photoelectron Spectroscopy (XPS) helped us identify the introduced surface functional group changes. Overall, nitridation resulted in an increased basic character of the surface exploiting the Lewis acidic nature of triclosan when it is dissolved in solution. The surface chemistry modified adsorbents suggest that adsorption from solution is a viable methodology for triclosan control during wastewater treatment.Item Metadata only Free chlorine analysers: a user's selection guide(Australian Water Association Inc, 2009) Badalyan, A.; Holmes, M.; Chow, C.; Vitanage, D.Selecting new instrumentation for integration into water quality monitoring programs is fraught with uncertainties and potential pitfalls. An evaluation methodology for assisting water managers and operators to make the correct choice of an online free chlorine (FC) analyser based on key performance parameters is presented. Eight amperometric and one colorimetric online FC monitors were evaluated against 15 metrological parameters (response, delay, rise and fall times, linearity, limit of quantification, day-to-day repeatability, the effect of interferences, etc.) according to the procedure outlined in the two standards: ISO Standards 8466-1 (1990) and 15839 (2003). The test results were compared with the analysers' technical characteristics supplied by their manufacturers. In general, colorimetric systems performed better than amperometric systems, with the latter experiencing significant interference from the pH of water which was not adjusted during tests. All analysers performed within manufacturers' claimed limits for some metrological parameters, whereas for other parameters their performance was not adequate. It is strongly encouraged to perform evaluation tests under conditions similar to those in the field before purchasing a monitor.Item Metadata only Mesoporous silica synthesis in sub- and supercritical carbon dioxide(Korean Inst Chem Engineers, 2010) Chun, B.; Pendleton, P.; Badalyan, A.; Park, S.; Institute for Mineral and Energy ResourcesMesoporous silicas were synthesized from sodium silicate (Na₂Si₃O₇) and tetraethylorthosilicate (TEOS) with Pluronic F127 (polyethylene oxide-polypropylene oxide-polyethylene oxide, EO₁₀₆PO₇₀EO₁₀₆) triblock copolymer using sub- and supercritical carbon dioxide (SubCO₂ and SCO₂) respectively, as solvents. Templates were removed using liquid carbon dioxide (LCO₂) and SCO₂. The most efficient template removal was achieved by LCO₂ − 92.7% (w/w), followed by LCO₂ with ethanol entrainer − 85.6% (w/w), and by methanol − 78.8% (w/w). The best efficiency of template removal by SCO₂ was 50.7%. Values of specific surface areas, ABET, were increased by 10% with the increase of an ageing time from 6 to 24 hours for Na₂Si₃O₇-based silicas at aqueous synthesis conditions, whereas the use of SCO₂ reduced this value by 19.4%. For TEOS-based silicas synthesized using SCO₂, A BET values increased by 3.8 times. Application of SCO₂ for synthesis of TEOS-based silicas resulted in higher mesopore volumes of 0.719 and 1.241 mL/g with an average mesopore width varying from 3.4 to 3.9 nm. Although Na₂Si₃O₇-based silicas have almost similar mesopore width range, their mesopore volumes were 7 times less than those for TEOS-based silicas. Formation of mesopores in Na₂Si₃O₇- and TEOS-based silicas was at the expense of micropores when synthesized in SCO₂.Item Metadata only On-line free-chlorine/total-chlorine monitors' evaluation - a step towards a correct choice of residual disinfectant monitor(IWA Publishing, 2009) Badalyan, A.; Buff, J.; Holmes, M.; Chow, C.; Vitanage, D.; Institute for Mineral and Energy ResourcesA number of commercially available on-line disinfection residual analysers were evaluated using a test rig under laboratory conditions. The methodology used for this trial was based on the following two standards: ISO Standard 15839 (2003), “Water Quality – On-line sensors/analysing equipment for water – Specifications and performance tests” and ISO 8466-1 (1990), and “Water Quality – Calibration and evaluation of analytical methods and estimation of performance characteristics. Part 1: Statistical evaluation of the linear calibration function”. The assessment of each analyser involved the determination of a set of performance characteristics including response delay, rise and fall times, linearity, limit of quantification and day–to-day repeatability. The effects of likely interferences were also covered. Results obtained from this trial for two total chlorine monitors were compared with the technical specifications as supplied by their respective manufacturers. This study concludes that persons responsible for instrument procurement should be cautious when relying only on manufacturers' technical specification claims. A more informed selection can be made by undertaking an evaluation study similar to the one described in this paper, as this will confirm the performance of a monitor under particular operating conditions. In general, residual disinfectant monitors utilising the colorimetric measurement method showed better performance than those employing amperometric/polarographic methods.