Doxycycline degradation by the oxidative Fenton process

Doxycycline is a broad-spectrum tetracycline occurring in domestic, industrial and rural effluents, whose main drawback is the increasing emergence of resistant bacteria. This antibiotic could be degraded by the so-called Fenton process, consisting in the oxidation of organic pollutants by oxygen peroxide (H2O2) in the presence of Fe2+. Experiments were performed according to an experimental Rotational Central Composite Design to investigate the influence of temperature (0 \u2013 40.0\ub0C), H2O2 concentration (100 \u2013 900 mg/L) and Fe2+ concentration (5 \u2013 120 mg/L) on residual doxycycline and total organic carbon concentrations. Whereas the final residual doxycycline concentration ranged from 0 to 55.8 mg/L, the oxidation process proved unable to reduce the total organic carbon by more than 30%. The best operating conditions were concentrations of H2O2 and Fe2+ of 611 and 25 mg/L, respectively, and temperature of 35.0\ub0C, but the analysis of variance revealed that only the first variable exerted a statistically-significant effect on the residual doxycycline concentration. These results suggest possible application of this process in the treatment of doxycycline-containing effluents and may be used as starting basis to treat tetracycline-contaminated effluents

Production of bacteriocin-like inhibitory substances (BLIS) by Bifidobacterium lactis using whey as a substrate

The objective of this work was to evaluate the production of bacteriocin-like inhibitory substances (BLIS) by Bifidobacterium animalis subsp. lactis in whey supplemented with yeast extract, inulin, Tween 80 or L-cysteine. Cell growth, acidification, glucose and lactose consumption as well as BLIS production were measured during fermentations carried out in shake flasks. The best additive for both cell growth and BLIS production was shown to be yeast extract, which gave the highest concentrations of biomass (9.9 log CFU/mL) and BLIS (800 AU/mL). In a bench-scale fermenter, B. lactis growth and BLIS production were between 6 and 25 % higher than in flasks depending on the conditions assayed

Adsorption of inorganic mercury from aqueous solutions onto dry biomass of Chlorella vulgaris: kinetic and isotherm study

This study focused on kinetics and equilibrium isotherms of mercury biosorption from water using dry biomass of Chlorella vulgaris as biosorbent at pH 5.0. Biosorption tests were performed at 2.0\u2005g/L biomass dosage varying initial Hg concentration from 11.0 to 90.6\u2005mg/L. The Lagergren equation was found to best describe the process, with R2of 0.984 and specific rate constant of 0.029\u2009\ub1\u20090.004 min 121. Although equilibrium data were well fitted by the Dubinin and Radushkevich isotherm (R2\u2009=\u20090.870; qDR\u2009=\u200916.6\u2005mg/g), important insights on phenomenological events occurring at equilibrium were concurrently provided by the Lamgmuir one (R2\u2009=\u20090.826; q0\u2009=\u200932.6\u2005mg/g; KL\u2009=\u20090.059\u2005L/mg). FT-IR analysis confirmed that Hg biosorption took place via physisorption. Since C. vulgaris is a fresh-water microalga that can be easily cultivated anywhere, these promising results suggest its possible use as an effective, low-cost biosorbent to treat industrial effluents contaminated by this metal

Study of Aromatic Compounds Derived from Sugarcane Bagasse. Part I: Effect of pH

none4siThis work aims at increasing the knowledge about the recovery of aromatic compounds from the lignin fraction of sugarcane bagasse, as well as exploring the possibility to recover these fine chemicals of great concern for many industrial sectors.mixedS. AL ARNI; A.F. DRAKE; M. DEL BORGHI; A. CONVERTIS., AL ARNI; A. F., Drake; DEL BORGHI, Marco; Converti, Attili

Study of Aromatic Compounds Derived from Sugarcane Bagasse: II. Effect of Concentration

The results of a set of experiments that were designed to integrate current knowledge on the major constituents of sugarcane bagasse lignin, specifically p-coumaric, ferulic, syringic acids, and vanillin are presented

Methods of Reactive Red 141 Dye Decolorization, Treatment, and Removal from Industrial Wastewaters: A Critical Review

Reactive Red 141 (RR141) is a diazo reactive dye with bright red color, high molecular weight (1774.15 g mol-1), large molecular structure (C52H26Cl2N14Na8O26S8) and several reactive groups. It is a source of water contamination, because of its wide use in industry and potential toxicity. The purpose of this work is to compare different treatment methods applied to industrial water effluents polluted, especially, by this dye. Recently, several research papers have been published on decolorization of RR141 in wastewater effluents. From this survey, nanofiltration membranes prepared through single bilayer polyelectrolyte deposition and electrocoagulation appeared to be best method, being able to ensure the highest percentage removal (99.9%) of RR141 within an application time of only about 11 min under optimum operating conditions. Nonetheless, other treatments appeared to be quite promising because of their ability to destroy the contaminant rather than simply remove it. Among them, the photo\u2013Fenton reaction was shown to ensure the most effective chemical degradation (98%) of RR141 from aqueous solution within 30 min using CuFeO2 as a catalyst, and Bacillus lentus BI377 its best biodegradation (99.1%) within 6 h. Further development of these methods is expected to allow more effective full-scale applications than the current ones to remove or degrade of these contaminants from wastewater in the future, with a focus on RR141

Activation energy and angular momentum in electromagnetic radiation micropolar nanofluids: Focus on microbial eukaryotic species

Microbial eukaryotic species play a crucial role in biomedical research, aiding in the study of bacterial impurities, microorganism pathogenesis, and development of tactics to combat antimicrobial struggle. These species represent a complex and diverse aspect of bacteriological life, influencing ecosystems, human health, and technological progress. This study aims to create a comprehensive computational model to analyze the magnetohydrodynamics of a non-Newtonian micropolar nanofluid over an exponentially stretchable surface. It incorporates the Buongiorno model, which considers thermophoretic diffusion and Brownian motion effects to study the thermal behavior of micropolar nanofluids. It is also investigated how thermal radiation affects the current model. The classical Navier's stokes equations of motions of the current model are transform into a system of ordinary differential equation by employing similarity approach. The classical Navier-Stokes equations of motion are transformed into ordinary differential equations using similarity transformations, and MATLAB is used to solve them numerically. Here we considered three different cases, (i)-injection fw>0, (ii)-impermeable wall fw=0, (iii)-suction fw<0 which are illustrated visually. The consequence of various flow parameters effects on velocity, temperature, concentration, motile microorganism, and angular profiles are illustrated graphically. The high concordance between the model's results and the available data validates its originality. Present results indicate that while a larger porosity and Hartman number decrease velocity, increasing the mass and thermal convective factors raises the velocity profile. Raising the thermophoretic and magnetic parameters causes the temperature profile to climb; however, raising the temperature exponent and Prandtl number causes it to fall. The behavior of micropolar nanofluids is better understood thanks to this research, which could have applications in a variety of industries including manufacturing, energy, electronics, and healthcare. The novelty of the current model is verified using data that has already been published, and a great agreement is observed. When the values of the parameter K lies between the ranges 0.2<K< 0.3, and 0.3<K< 0.4, percentage increment noted in heat transfer enhancement is about 2.3 % and 6.3 % Until now, no such investigation has been performed to examine the implications of three-dimensional bio-convection micropolar based Casson fluid flow under the activation energy and suction/injection. From the outcomes, it was established that nanofluids are more fruitful for heat transfer enhancement

Turbulent and non-turbulent analysis of thermomagnetic convection and heat transfer of darcian radiative nanofluid flow across inclined stretching surface in microgravity environment

Turbulent and non-turbulent analysis of thermomagnetic convection, heating rate and mass transport of Darcian radiating nanofluid flow through porous slanted sheet is the aim of present study. Influence of microgravity is more useful for the movement of thermophoresis nanoparticles with maximum temperature and density. Joule heating, porous medium, magnetic field and thermal radiations are incorporated for the performance of thermal convection. Governing equations are reduced in dimensionless form. Oscillatory stokes conditions are applied to separate the steady, real and imaginary equations. Finite difference, Primitive transformation, and Gaussian elimination techniques are applied for numerical outputs. For asymptotic results, the appropriate range of parameters such as 0.1≤JH≤15.0, 0.1≤Pr≤12.0, 0.1≤Rd≤25.0, 0.0≤λT≤5.0, 0.1≤NT≤1.0, 0.1≤Fr≥6.0, and 0.1≤δ≤1.0 is utilized. Main novelty of work is to examine the steady state and oscillatory behavior of friction-rate, heat/mass transport over slanted two-angles π/6 and π/4. Maximum amplitude in fluid velocity is observed by increasing radiations and buoyant forces. Temperature distribution and nanomaterial concentrations enhance as Joule-heating and Prandtl number increases under microgravity region. Amplitude and oscillation of heat and mass rate is increased as reaction rate, Joule heating and Forchheimer parameter increases. Enhancing behavior of energy transport is observed for maximum choice of Prandtl index with small magnetic effects. It is depicted that high rate of oscillating frequency in heat transmission is detected with maximum radiation effects

Oscillatory and non-oscillatory analysis of heat and mass transfer of Darcian MHD flow of nanofluid along inclined radiating plate with joule heating and multiple slip effects: Microgravity analysis

In current analysis, the contributions of Joule heating, microgravity, thermal radiations, and porous medium on magnetized Darcy Forchheimer flow of nanofluid with multiple slips are studied. The flow behavior is caused by the inclined surface with velocity slip, thermal slip and concentration slip. The motivation of this analysis is to improve the polishing and cleaning of artificial cardiovascular valves, inner arteries, lubrications, ballistic missiles, aircrafts and plastic fabrications. The microgravity is assumed as temperature dependent with maximum density of nanoparticles for increasing motion along inclined surface. The optimizing non-linear periodical model with slip boundaries is transformed using implicit form of finite difference asymptotic method. Numerical outputs of steady solutions are recorded first for different flow parameters and then used these steady solutions in periodical formula for oscillating skin frictions, oscillating heat rates and oscillating mass rates. It is depicted that significant amplitude in slip velocity is obtained for increasing values of slip-velocity, thermal radiation and slip-thermal parameters. Steady state heat and mass transmission is enhanced for minimum Joule heating impacts along both inclined angles. It is noticed that the steady skin friction and mass transfer enhances as Prandtl value enhances. The minimum layer in mass transfer is observed for small value of Brownian motion but high amplitude in mass rate enhances as Brownian motion enhances. It is depicted that the prominent oscillations and fluctuating amplitude in mass and heat transfer is deduced for maximum values of Schmidt number and thermophoresis parameter. The prominent stability in heat transfer is observed for each value of Schmidt number. The current study is useful in various applications such as energy transport in groundwater, renewable energy devices, geothermal energy sources, crops preservation, nuclear power-plants, biological and chemical processes, heat removal in radioactive waste, and radiators for porous substances