Use of hydrodynamic cavitation in (waste)water treatment

The use of acoustic cavitation for water and wastewater treatment (cleaning) is a well known procedure. Yet, the use of hydrodynamic cavitation as a sole technique or in combination with other techniques such as ultrasound has only recently been suggested and employed.In the first part of this paper a general overview of techniques that employ hydrodynamic cavitation for cleaning of water and wastewater is presented.In the second part of the paper the focus is on our own most recent work using hydrodynamic cavitation for removal of pharmaceuticals (clofibric acid, ibuprofen, ketoprofen, naproxen, diclofenac, carbamazepine), toxic cyanobacteria (Microcystis aeruginosa), green microalgae (Chlorella vulgaris), bacteria (Legionella pneumophila) and viruses (Rotavirus) from water and wastewater.As will be shown, hydrodynamic cavitation, like acoustic, can manifest itself in many different forms each having its own distinctive properties and mechanisms. This was until now neglected, which eventually led to poor performance of the technique. We will show that a different type of hydrodynamic cavitation (different removal mechanism) is required for successful removal of different pollutants.The path to use hydrodynamic cavitation as a routine water cleaning method is still long, but recent results have already shown great potential for optimisation, which could lead to a low energy tool for water and wastewater cleaning.     

Evidence of high-frequency acoustic emissions from the white-beaked dolphin (Lagenorhynchus albirostris)

Recordings of the signals from a school of white-beaked dolphins show that the frequency of their acoustic emissions extends to at least 305 kHz. These signals were detected by a sector scanning sonar used as a passive listening device of high bearing and time resolution. The records contain three types of signal, one of high intensity, one of a variable high repetition rate, and another showing a time-varying effect. Acoustic signals radiated by dolphins have been recorded and studied over a long period of time by many investigators. The purpose of this letter is to report evidence that acoustic emissions from white-beaked dolphins have significant energy at frequencies around 305 kHz, about one octave higher than previously observed. The observations discussed here were made aboard the fisheries research vessel CLIONE in the Wellbank flat area of the southern North Sea on 13 June 1970 between 1040 and 1110 h. When the dolphin signals were observed, the transmitter of the sector-scanning sonar in use was turned off, and the system was utilized as a passive listening device of high bearing and time resolution.     

Supercritical water oxidation (SCWO): a process for the treatment of industrial waste effluents

Abstract

SuperCtical Water Oxidation (SCWO) process is investigated at the Institut of Technical Chemistry, ITC-CPV. The objectives were to determine destruction efficiencies of model compounds and industrial waste effluents and to study the feasability of the SCWO process.

Two continuous SCWO bench scale plants are operated a pipe reactor and a transpiring wall reactor system (design data: T= 630°C, P = 32MPa, feed rate waste water =10 and 50kg/h, air feed rate = 20kglh, transpiring and quench water feed rate = 50 kg/h). Suspensions containing up to 5%wt solid material can be fed to the reactor using a membrane pump.

With the pipe reactor, efficiencies of up to 99.99% were achieved for the oxidation of model compounds (ethanol, toluene, phenol) as well as real waste effluents (paper, chemical, pharmaceutical industry, sewage works). The use of the pipe reactor is limited to feeds without salt to avoid plugging.

Salty feeds are processed using the transpiring wall reactor, which is consisting of a pressure bearing tube outside and a porous tube as reactor inside. Water is steadily running through the porous reactor preventing the formation of deposits on the wall.

SCWO has a high potential at least for the destruction of halogented organic compounds using the transpiring wall reactor system and is seen to be competitive to other processes for waste destruction.     

Advanced oxidation processes (AOPs) involving ultrasound for waste water treatment: A review with emphasis on cost estimation

Two things are needed for any technology to be suitable for use in the industry, viz. 1. Technical feasibility and 2. Economical feasibility. The use of ultrasound for waste water treatment has been shown to be technically feasible by numerous reports in the literature over the years. But there are hardly any exhaustive reports which address the issue of economical feasibility of the use of ultrasound for waste water treatment on industrial scale.Hence an attempt was made to estimate the cost for the waste water treatment using ultrasound. The costs have been calculated for 1000 L/min capacity treatment plant. The costs were calculated based upon the rate constants for pollutant degradation. The pollutants considered were phenol, trichloroethylene (TCE) and reactive azo dyes. Time required for ninety percent degradation of pollutant was taken as the residence time. The amount of energy required to achieve the target degradation was calculated from the energy density (watt/ml) used in the treatability study. The cost of treatment was calculated by considering capital cost and operating cost involved for the waste water treatment. Quotations were invited from vendors to ascertain the capital cost of equipments involved and operating costs were calculated based on annual energy usage. The cost was expressed in dollars per 1000 gallons of waste water treated. These treatment costs were compared with other established Advanced Oxidation Process (AOP) technologies. The cost of waste water treatment for phenol was in the range of $89 per 1000 gallons for UV/US/O₃ to $15,536 per 1000 gallons for US alone. These costs for TCE were in the range of $25 per 1000 gallons to $91 for US + UV treatment and US alone, respectively. The cost of waste water treatment for reactive azo dyes was in the range of $65 per 1000 gallon for US + UV + H₂O₂ to $14,203 per 1000 gallon for US alone.This study should help in quantifying the economics of waste water treatment using ultrasound on industrial scale. We strongly believe that this study will immensely help the researchers working in the area of applications of ultrasound for waste water treatment in terms of where the technology stands today as compared to other available commercial AOP technologies. This will also help them think for different ways to improve the efficiency of using ultrasound or search for other ways of generating cavitation which may be more efficient and help reduce the cost of treatment in future.     

Hypernuclear properties derived from the Jülich hyperon-nucleon interaction (in comparison with the Nijmegen interactions)

TheG-matrix interactions are derived from the Jülich YN interaction models A and B, and compared with those from the Nijmegen models. The DDHF calculations for heavy A hypernuclei and the shell-model analysis for spin-doublet states of light hypernuclei are performed by use of theG-matrix interactions. It is demonstrated that the OBE models can be tested by the hypernuclear calculations.     

Crystal structure of Ni(II) complex and fluorescence properties of Zn(II) complex with the Schiff base derived from diethenetriamine and PMBP

The Schiff base, H₂L, was derived from 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) and diethenetriamine. The crystal structure of [NiL(C₂H₅OH)]·H₂O obtained from ethanol solution was determined by X-ray diffraction analysis. The coordination geometry of Ni(II) ion is a distorted octahedron with three oxygen atoms and three nitrogen atoms. Under the excitation of ultraviolet light, strong fluorescence of solid Zn(II) complex was observed. In addition, the fluorescence enhancement was obtained in the presence of Zn²⁺ in THF solution of the ligand, indicating that H₂L may be a potential fluorescent sensor for Zn²⁺.     

Prediction of NOx emissions from a simplified biodiesel surrogate by applying stochastic simulation algorithms (SSA)

A stochastic simulation algorithm (SSA) approach is implemented with the components of a simplified biodiesel surrogate to predict NOx (NO and NO₂) emission concentrations from the combustion of biodiesel. The main reaction pathways were obtained by simplifying the previously derived skeletal mechanisms, including saturated methyl decenoate (MD), unsaturated methyl 5-decanoate (MD5D), and n-decane (ND). ND was added to match the energy content and the C/H/O ratio of actual biodiesel fuel. The MD/MD5D/ND surrogate model was also equipped with H₂/CO/C₁ formation mechanisms and a simplified NOx formation mechanism. The predicted model results are in good agreement with a limited number of experimental data at low-temperature combustion (LTC) conditions for three different biodiesel fuels consisting of various ratios of unsaturated and saturated methyl esters. The root mean square errors (RMSEs) of predicted values are 0.0020, 0.0018, and 0.0025 for soybean methyl ester (SME), waste cooking oil (WCO), and tallow oil (TO), respectively. The SSA model showed the potential to predict NOx emission concentrations, when the peak combustion temperature increased through the addition of ultra-low sulphur diesel (ULSD) to biodiesel. The SSA method used in this study demonstrates the possibility of reducing the computational complexity in biodiesel emissions modelling.     

Proton-conducting composite membranes derived from poly(2,6-dimethyl-1, 4-phenylene oxide) doped with phosphosilicate gels

Proton-conducting composite membranes were prepared by doping phosphosilicate gels into SPPO polymer matrix. The structure of gels was examined by ³¹P MAS-NMR. The composite membranes were characterized in terms of TGA, mechanical property, water uptake and conductivity. It was found that the composite membranes were thermally stable up to 150 °C, and possessed higher mechanical strength than Nafion112, either in dry state or in wet state. The conductivity of composite membranes increased with the increase of the ion exchange capacity (IEC), relative humidity (R.H.) and doping amounts. The water uptakes of composite membranes are much higher than Nafion112 in weight percent form at room temperature, and the highest conductivity value of 0.216 S cm^− 1 was achieved for water equilibrated membranes, 2.5 times higher than 0.0871 S·cm^− 1 for Nafion112 measured under the same condition. It is suggested that the composite membranes should be the promising candidates used in PEMFC.     

Synthesis, thermal and optical properties of metal(II) complexes with a novel ligand derived from pyrazolone-5

Three novel metal(II) complexes, CoL₂, NiL₂ and CuL₂ (L = (Z)-4-(2-(1,3-dimethyl-5-oxo-1H-pyrazol-4(5H)-ylidene)hydrazinyl)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one were synthesized. Their structures were postulated based on elemental analyses, ¹H NMR, ESI-MS, FT-IR spectra and UV-vis spectra. The effect of different central metal(II) ions on absorption bands of the metal(II) complexes in CHCl₃ solutions was researched. The result indicates that the bathochromic shift is CuL₂ > NiL₂ > CoL₂. The absorption properties of thin films and thermal stability of these complexes are also discussed. In addition, the optical constants (complex refractive index N=n+ik) and thickness of the complex thin films on polished single-crystal silicon substrates were measured by spectroscopic ellipsometry. Results indicate that the metal(II) complexes would be a promising recording medium candidate for blu-ray recordable optical storage system due to good absorption at 405 nm, high thermal stability and sharp thermal decomposition, and a high n values of 1.35–1.45 and a low k values of 0.33–0.39.     

Synthesis of block copolymers derived from N-trityl-(S)-serine and pyrene end-labeled poly(methyl methacrylate) or poly(N-isopropylacrylamide) via ATRP

A new monomer bearing N-trityl-l-serine methyl ester in structure, methacryloyloxyethyl carbamoyloxy–N-trityl methyl serine (MTS), was prepared to be further polymerized by atom transfer radical polymerization (ATRP) with pyrene-endcapped poly(methyl methacrylate) (Py–PMMA–Br) or poly(N-isopropylacrylamide) (Py–PNIPA–Br). The resulting block copolymers, poly(methyl methacrylate–block–methacryloyloxyethyl carbamoyloxy–N-trityl methyl serine) (Py–PMMA–b–PMTS) and poly(N-isopropylacrylamide–block–methacryloyloxyethyl carbamoyloxy–N-trityl methyl serine (Py–PNIPA–b–PMTS) were characterized by ¹H (¹³C) NMR, ultraviolet, FTIR and fluorescence spectroscopy, thermal analysis, differential scanning calorimetry (DSC), atomic force microscopy (AFM), scanning electron microscopy (SEM), and gel permeation chromatography (GPC) measurements. The chemical composition in Py–PMMA–b–PMTS was estimated from the ¹H NMR analysis that indicated a ratio of the repeating units of 46:19 (MMA:MTS). For the Py–PNIPA–b–PMTS the composition rate in the copolymer was 61:25 (NIPA:MTS). Quenching of the pyrene species with N,N-diethylaniline, nitrobenzene, nitrophenol, potassium iodide, p-nitrotoluene and tetracyanoquinodimethane (TCNQ) in DMF solution excited at 348 nm was evidenced, more efficiently being nitrophenol and TCNQ. In this case, the monomer emission at 388–409 nm underwent a significant decrease caused of an electron transfer from the electron-reach photoexcited pyrene molecule to the electron-deficient quenchers.     

纸杯中残留苯并(a)芘在食品模拟物中的相对迁移率研究

采用具有高分辨、高灵敏度的导数-恒能量同步荧光法分析测定了不同条件下,纸杯中残留苯并(a)芘在水性模拟液和脂肪模拟液中的迁移量.探讨了模拟物的种类、浸泡时间和温度对纸杯中苯并(a)芘的相对迁移率的影响.结果表明:该分析方法的回收率为89.2～104.3%;纸杯中残留苯并(a)芘在脂肪模拟液中的相对迁移率明显高于水性模拟液的,纸杯盛装冷水时无苯并(a)芘浸出.而用于盛装热水可浸出苯并(a)芘;温度越高,浸泡时间越长,纸杯中苯并(a)芘向食品模拟液的相对迁移率也越大.     

Removal of organic contaminants from aqueous solution by cattle manure compost (CMC) derived activated carbons

The activated carbons (ACs) prepared from cattle manure compost (CMC) with various pore structure and surface chemistry were used to remove phenol and methylene blue (MB) from aqueous solutions. The adsorption equilibrium and kinetics of two organic contaminants onto the ACs were investigated and the schematic models for the adsorptive processes were proposed. The result shows that the removal of functional groups from ACs surface leads to decreasing both rate constants for phenol and MB adsorption. It also causes the decrement of MB adsorption capacity. However, the decrease of surface functional groups was found to result in the increase of phenol adsorption capacity. In our schematic model for adsorptive processes, the presence of acidic functional groups on the surface of carbon is assumed to act as channels for diffusion of adsorbate molecules onto small pores, therefore, promotes the adsorption rate of both phenol and MB. In phenol solution, water molecules firstly adsorb on surface oxygen groups by H-bonding and subsequently form water clusters, which cause partial blockage of the micropores, deduce electrons from the π-electron system of the carbon basal planes, hence, impede or prevent phenol adsorption. On the contrary, in MB solution, the oxygen groups prefer to combine with MB⁺ cations than water molecules, which lead to the increase of MB adsorption capacity.     

Formation of the bisulfite anion (HSO(3) (-) , m/z 81) upon collision-induced dissociation of anions derived from organic sulfonic acids

In the negative-ion collision-induced dissociation mass spectra of most organic sulfonates, the base peak is observed at m/z 80 for the sulfur trioxide radical anion (SO(3) (-·) ). In contrast, the product-ion spectra of a few sulfonates, such as cysteic acid, aminomethanesulfonate, and 2-phenylethanesulfonate, show the base peak at m/z 81 for the bisulfite anion (HSO(3) (-) ). An investigation with an extensive variety of sulfonates revealed that the presence of a hydrogen atom at the β-position relative to the sulfur atom is a prerequisite for the formation of the bisulfite anion. The formation of HSO(3) (-) is highly favored when the atom at the β-position is nitrogen, or the leaving neutral species is a highly conjugated molecule such as styrene or acrylic acid. Deuterium-exchange experiments with aminomethanesulfonate demonstrated that the hydrogen for HSO(3) (-) formation is transferred from the β-position. The presence of a peak at m/z 80 in the spectrum of 2-sulfoacetic acid, in contrast to a peak at m/z 81 in that of 3-sulfopropanoic acid, corroborated the proposed hydrogen transfer mechanism. For diacidic compounds, such as 4-sulfobutanoic acid and cysteic acid, the m/z 81 ion can be formed by an alternative mechanism, in which the negative charge of the carboxylate moiety attacks the α-carbon relative to the sulfur atom. Experiments conducted with deuterium-exchanged and deuterium-labeled analogs of sulfocarboxylic acids demonstrated that the formation of the bisulfite anion resulted either from a hydrogen transfer from the β-carbon, or from a direct attack by the carboxylate moiety on the α-carbon.     

A time-resolved imaging study of Cr (I) emissions from a laserplasma formed on a sample at nonnormal incidence

The effect of sample orientation on atomic emission in laser-induced breakdown spectroscopy (LIBS) was studied using time-resolved imaging and spectroscopy. The purpose of this work was to determine the effect of sampling geometry on the analytical performance of the LIBS measurement. The results obtained indicate that atoms are ejected perpendicular to the sample surface independent of the angle-of-incidence of the laser pulse. This result is consistent with previous work by others. In addition, it was found that the observed LIBS atomic emission intensities were maximum for normal laser pulse incidence, reached a minimum at 50° angle-of-incidence, and then increased as the sample was rotated to higher angles-of-incidence     

In Silico study of carcinogenic o‐Quinone metabolites derived from polycyclic aromatic hydrocarbons (PAHs)

A computational density functional theory study on the structural and electronic properties of several polycyclic aromatic hydrocarbon (PAH) ortho‐quinones was performed and the possible mechanism of DNA‐adduct formation was analyzed to evaluate its thermodynamic viability. Molecular docking techniques were applied to examine the noncovalent interactions developed when a model PAH ortho‐quinone intercalates between the DNA double helix. Quantum‐chemical ONIOM (our Own N‐layer Integrated molecular Orbital molecular Mechanics) calculations within the structure of a DNA fragment were carried out to evaluate the significant steps of noncovalent complex and covalent adduct formation. The solvent effect was also considered by employing a continuum solvation model. The present calculations suggest that initial noncovalent interactions of the PAH o‐quinone within the DNA double helix could determine the feasibility of benzo[a]pyrene‐7,8‐dione‐DNA covalent adduct formation, and that dispersion‐corrected functionals are more suitable for locating the noncovalent complex. Copyright © 2012 John Wiley & Sons, Ltd.     

Selective detection of hyperpolarized NMR signals derived from para-hydrogen using the Only Para-hydrogen SpectroscopY (OPSY) approach

A new family of NMR pulse sequences is reported for the recording of para-hydrogen enhanced NMR spectra. This Only Para-hydrogen SpectroscopY (OPSY) approach uses coherence selection to separate hyperpolarized signals from those of fully relaxed and thermally equilibrated protons. Sequence design, performance, practical aspects and applicability to other hyperpolarization techniques are discussed.     

Peptide internal motions on nanosecond time scale derived from direct fitting of (13)C and (15)N NMR spectral density functions

NMR relaxation-derived spectral densities provide information on molecular and internal motions occurring on the picosecond to nanosecond time scales. Using (13)C and (15)N NMR relaxation parameters [T(1), T(2), and NOE] acquired at four Larmor frequencies (for (13)C: 62.5, 125, 150, and 200 MHz), spectral densities J(0), J(omega(C)), J(omega(H)), J(omega(H) + omega(C)), J(omega(H) - omega(C)), J(omega(N)), J(omega(H) + omega(N)), and J(omega(H) - omega(N)) were derived as a function of frequency for (15)NH, (13)C(alpha)H, and (13)C(beta)H(3) groups of an alanine residue in an alpha-helix-forming peptide. This extensive relaxation data set has allowed derivation of highly defined (13)C and (15)N spectral density maps. Using Monte Carlo minimization, these maps were fit to a spectral density function of three Lorentzian terms having six motional parameters: tau(0), tau(1), tau(2), c(0), c(1), and c(2), where tau(0), tau(1) and tau(2) are correlation times for overall tumbling and for slower and faster internal motions, and c(0), c(1), and c(2) are their weighting coefficients. Analysis of the high-frequency portion of these maps was particularly informative, especially when deriving motional parameters of the side-chain methyl group for which the order parameter is very small and overall tumbling motions do not dominate the spectral density function. Overall correlation times, tau(0), are found to be in nanosecond range, consistent with values determined using the Lipari-Szabo model-free approach. Internal motional correlation times range from picoseconds for methyl group rotation to nanoseconds for backbone N-H, C(alpha)-H, and C(alpha)-C(beta) bond motions. General application of this approach will allow greater insight into the internal motions in peptides and proteins.