Publications by authors named "Ajay K Ray"

Light-driven photocatalytic (PC) and photoelectrocatalytic (PEC) systems are vital technologies being extensively explored for wastewater treatment and energy production. Although the photo(electro)catalytic applications in both the energy production and wastewater remediation function on the similar principle of photo-induced charge transfer, most preceding research has been focused on either the energy recovery or wastewater treatment as these two applications demand distinct reaction parameters and catalyst properties. The present review reveals the scientific progress in dual-functional PC and PEC processes that enable simultaneous energy recovery (e.

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Disinfection of combined sewer overflow (CSO) is necessary to reduce the amount of microorganisms discharged into surface waters. In this study, an efficient and cost-competitive treatment for CSO, employing UV disinfection, was developed. High suspended solids content in CSO poses a significant challenge for UV disinfection so laboratory experiments were carried out to asses the effect of chemical pre-treatment followed by micro-sieve filtration on the reduction of total suspended solids (TSS) and the increase of UV transmittance (UVT).

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Current study addresses a problem of elevated aluminum concentrations deteriorating Khibiny Alkaline Massif groundwater quality. The application of chemometric methods to the field dataset 1999-2018 allows to quantitatively describe the groundwater quality, reveal variability patterns and potential sources of elevated aluminum level in the groundwater. The field dataset contains almost 40% more observations of 12 physicochemical groundwater quality parameters than the dataset analyzed in our previous studies on Khibiny groundwater quality assessment reported in the literature.

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Ferrate(VI) (FeO, Fe(VI)) is an emerging oxidant/disinfectant to treat a wide range of contaminants and microbial pollutants in wastewater. This study describes the inactivation of murine norovirus (MNV) by Fe(VI) in phosphate buffer (PB) and secondary effluent wastewater (SEW). The decay of Fe(VI) had second-order kinetics in PB while Fe(VI) underwent an initial demand followed by first-order decay kinetics in SEW.

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Coagulation and flocculation can remove particulate algal cells effectively; however, they are not very effective for removing dissolved algal organic matter (AOM) in drinking water plants. In this work, optimum coagulation conditions using alum for both extracellular and intracellular organic matter of six different algal and cyanobacterial species were determined. Different coagulation conditions such as alum dosage, pH, and initial dissolved organic carbon (DOC) were tested.

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Combined sewer overflows contain a highly variable, wide range of contaminants, both in particulate and soluble form, making conventional water treatment processes unable to offer adequate public health protection. In this study, an integrated treatment process designed to simultaneously remove typical combined sewer overflow pollutants (suspended solids, chemical oxygen depends, turbidity) in conjunction with nutrient (nitrogen and phosphorus), was developed. The removal of particulates as well as dissolved nitrogen and phosphorus was achieved by first adsorbing soluble pollutants on zeolite and powdered activated carbon, and subsequently applying filtration carried out by polymer-enhanced microsieving.

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Acesulfame potassium (ACE) is a widely used artificial sweetener that has consistently been detected in wastewater and surface waters. The high-valent iron-based green oxidant known as ferrate(VI) (potassium ferrate(VI); Fe(VI)) had low reactivity with ACE (i.e.

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The field dataset including physico-chemical characteristics of Khibiny alkaline massif groundwater aquifer was analysed for the first time by applying chemometric methods to explore the relationships between investigated parameters in both time and frequency domains. Elevated Al concentration in water of this aquifer is described as a serious health concern when used for the household water supply. The time series of 12 physico-chemical parameters were examined by using Pearson correlation, multiple linear regression and spectral analysis based on fast Fourier transform (FFT) algorithm.

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Article Synopsis
  • Resistance to antibacterial drugs and pesticides in water is growing, posing risks to human health and ecosystems, prompting a study on the presence and removal of these substances in wastewater from two treatment plants.
  • Screening identified multiple pharmaceuticals and pesticides at significant concentrations, with a range of 0.15 ng/L to 413.03 ng/L in secondary effluent wastewaters.
  • The study found that acid-activated ferrate(VI) significantly improved the degradation of selected pharmaceuticals and pesticides compared to non-activated Fe(VI), demonstrating potential effectiveness in reducing micropollutants in real wastewater.
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Diclofenac (DCF), a widely used non-steroidal anti-inflammatory drug, is a commonly detected substance that readily accumulates in tissues of aquatic fish and poses a threat to wildlife and freshwater quality. Advanced Oxidation Processes have been employed as an alternative due to the inadequacy of conventional treatment methods of trace contaminants. This study utilized an innovative method of solar-activation of TiO using Eosin-Y dye for the degradation of DCF.

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Background: Most commonly practiced surgical "lay open" technique to treat fistula-in-ano (a common anorectal pathology) has high rate of recurrence and anal incontinence. Alternatively, a nonsurgical cost efficient treatment with Ksharasutra (cotton Seton coated with Ayurvedic medicines) has minimal complications. In our study, we have tried to compare these two techniques.

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Ion-Exchange Chromatography (IEC) techniques have been extensively investigated in protein purification processes, due to the more selective and milder separation steps. To date, existing studies of minor whey proteins fractionation in IEC have primarily been conducted as batch uptake studies, which require more experimental search space, time and materials. In this work, the selected resin's (SP Sepharose FF) equilibrium and dynamic binding capacity were first investigated.

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This paper presents the results of a study conducted on the treatment of combined sewer overflows using ferrate (VI) [Fe (VI)]. At a Fe (VI) dose of 0.24 mg/L, total chemical oxygen demand (TCOD), soluble chemical oxygen demand (SCOD), total biochemical oxygen demand (TBOD5), soluble biochemical oxygen demand (SBOD5), total suspended solids (TSS), volatile suspended solids (VSS), total phosphorus (TP), total nitrogen (TN), and soluble TN removal efficiencies of 71, 75, 69, 68, 72, 83, 64, 38, and 36%, respectively, were achieved.

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Size exclusion chromatography has been demonstrated as an effective method for refolding a variety of proteins. However, to date process development mainly relies on laboratory experimentation of individual factors. A robust model is essential for high-throughput process screening and optimization of systems to provide higher productivity and refolding yield.

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In this paper, we have studied Eosin Y-sensitized sacrificial hydrogen generation with triethanolamine as electron donor in UV, visible, and solar light irradiation. Aeroxide TiO2 was loaded with platinum metal via solar photo-deposition method to reduce the electron hole recombination process. Photocatalytic sacrificial hydrogen generation was influenced by several factors such as platinum loading (wt%) on TiO2, solution pH, Eosin Y to Pt/TiO2 mass ratio, triethanolamine concentration, and light (UV, visible and solar) intensities.

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Chromatographic-based protein refolding techniques have proven to be superior to conventional dilution refolding methods, due to the higher loading concentration and simultaneous purification. Among these techniques, Size Exclusion Chromatography (SEC) has in particular been demonstrated as an effective method for refolding of variety of proteins. To date existing studies of protein refolding at high concentrations (>1mg/mL) in SEC have primarily been conducted as single factor studies, in which a single parameter is varied to assess impact on operating performance, which does not allow for determination of the interactions of different operating parameters and optimized operating conditions.

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Resolution of racemic mandelic acid ((R,S)-MA) and numerical determination of binary competitive isotherm of (R,S)-MA on Chiralcel-OD column have been investigated in this study. The effects of the alcohol modifier and acidic additive in the mobile phase on the retention and enantioseparation of (R,S)-MA were studied at first. The inverse method was then used to determine the competitive isotherm parameters of (R,S)-MA by minimizing the sum of square deviations of the model predictions from the measured elution profiles.

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Article Synopsis
  • - Iodinated X-ray contrast media (ICM), like diatrizoic acid (DTZA), is commonly used in hospitals but is not biodegradable, leading to its presence in various water sources.
  • - This study investigates how effective ferrate(VI) (Fe(VI)) is at oxidizing DTZA in water, focusing on how different pH levels (from 7.1 to 9.6) affect the reaction rate.
  • - The results show that the reaction rate of Fe(VI) with DTZA is first-order and decreases as pH increases, with the behavior explained by the types of Fe(VI) present at varying pH levels.
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An innovative route to prepare highly-ordered and dimensionally controlled TiO2 nanotubes has been proposed using a mild sonication method. The nanotube arrays were prepared by the anodization of titanium in an electrolyte containing 3% NH4F and 5% H2O in glycerol. It is demonstrated that the TiO2 nanostructures has two layers: the top layer is TiO2 nanowire and underneath is well-ordered TiO2 nanotubes.

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The photocatalytic oxidation of nonionic surfactant, Brij 35 in aqueous TiO2 suspensions was investigated as a function of catalysts loading, light intensity (I), initial Brij 35 concentration [Brij](0), dissolved oxygen concentration [p(O2)], and pH. A monolithic swirl-flow photoreactor was used that allowed to perform a systematic analysis of rates at various loadings of TiO22 in order to distinguish "kinetic" and "transport" limited regimes for the photocatalytic degradation of Brij 35 in TiO2 suspensions. The optimal catalyst loading was determined to be 0.

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A one-step method for the fabrication of Fe-C-N-codoped TiO2 nanotubes by electrochemical anodization is reported. The proposed method is both simple and efficient. The prepared samples were annealed at 550 degrees C for 3 h.

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Liquid-solid circulating fluidized bed (LSCFB) is an integrated two-column (downcomer and riser) system which can accommodate two separate processes (adsorption and desorption) in the same unit with continuous circulation of the solid particles between the two columns. In this study, a mathematical model based on the assumption of homogeneous fluidization was developed considering hydrodynamics, adsorption-desorption kinetics and liquid-solid mass transfer. The simulation results showed good agreement with the available experimental results for continuous protein recovery.

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Like most real-life processes, the operation of liquid-solid circulating fluidized bed (LSCFB) system for continuous protein recovery is associated with several objectives such as maximization of production rate and recovery of protein, and minimization of amount solid ion-exchange resin requirement, all of which need to be optimized simultaneously. In this article, multiobjective optimization of a LSCFB system for continuous protein recovery was carried out using an experimentally validated mathematical model to find the scope for further improvements in its operation. Elitist non-dominated sorting genetic algorithm with its jumping gene adaptation was used to solve a number of bi- and tri-objective function optimization problems.

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This paper reviews the current knowledge on the occurrence, biodegradation, and photooxidation of nonylphenol (NP), octylphenol (OP), and bisphenol-A (BPA) in aquatic environment. Generally, the concentrations determined were 0.006-32.

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The use of inverse method for the determination of competitive adsorption isotherm of mandelic acid enantiomers on cellulose tris(3,5-diethylphenyl carbamate) stationary phase is proposed in this work. Non-dominated sorting genetic algorithm with jumping genes (NSGA-II-JG) was applied to acquire the isotherm parameters by minimizing the sum of square deviations of the model predictions from the measured elution profiles. Three different competitive isotherm models, i.

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