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A two-step process was used to prepare a nickel-polyaniline nanocomposite (Ni (NPs)-PANI). The first step consisted of the electrodeposition of polyaniline (PANI) in the form of thin films on fluorine-doped tin oxide (FTO) substrates from a solution of aniline, lithium perchlorate, and sulfuric acid at a pH of 0.5. In the next step, the obtained Ni (NPs) were deposed in this polyaniline films. The structural, morphological, and electrocatalytic properties of the prepared nanocomposites were then investigated. X-ray diffraction (XRD) confirmed the cubic structure of the nanocomposites, and Fourier-transform infrared spectroscopy (FTIR) indicated the existence of nickel and polyaniline in the prepared nanocomposites. Morphological analysis carried out through SEM revealed that the nanocomposites exhibit uniform dispersion of nickel nanoparticles into the polyaniline matrix. Amperometry and cyclic voltammetry were employed to investigate the electrocatalytic glucose oxidation behavior of the nanocomposite electrode in the alkaline medium. The prepared nickel-polyaniline nanocomposite electrode exhibited high sensitivity (278.8 µA mM−1 cm−2) in a range from 0.02 to 1 mM at a sufficiently fast response time of 3 s and a low glucose detection limit of 1 µM (S/N = 3). A cost-effective and straightforward synthesis procedure to prepare Ni (NPs)-PANI nanocomposite would make this material an efficient glucose sensor with appropriate stability, higher reproducibility, and excellent sensitivity.

Pesticides are chemical compounds that are considered toxic to many organisms, including humans. Their elimination from polluted sites attracted the attention of Scientifics in the last decade; Among the various methods used to decontaminate pesticides from the environment, the microbial-algae consortium is a promising bioremediation technology, which implies several advantages as an eco-friendly process that generate biomass produced that could be valorized in the form of bioenergy, In this review, we will discuss the latest eco-friendly approaches using microorganisms to remediate sites contaminated by pesticides, and shows the ability of microbial, algae and their consortium to remove pesticides and the role of different enzymes in degradation processes.

Natural clay (NC) was employed as a natural adsorbent for the elimination of an azo dye Crystal Violet (CV) from aqueous media. The characterization of the clay was performed by X-ray diffractometry (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) equipped with an X-ray energy dispersion spectrometer (EDS) and Brunauer-Emmett-Teller (BET) specific surface area analysis. The Box-Behnken design (BBD) was used as a powerful tool to determine the stationary points of the main independent factors: initial CV concentration, initial pH, temperature, and adsorbent dose on the adsorption efficiency. The significance and adequacy of the model were investigated using analysis of variance (ANOVA). The obtained results indicated an optimal dye removal of 99.1% at pH = 3, initial CV concentration of 11.767 mg/L, adsorbent load of 3.075 g/L, and T = 298.0 K. The kinetic study was evaluated using three models: a pseudo-first-order (PFO), a pseudo-second-order (PSO), and an intraparticle diffusion model. The observed kinetics is in excellent agreement with the PSO kinetic model. Therefore, both isotherms Langmuir and Freundlich fitted well the adsorption equilibrium data. The thermodynamic study revealed that the main parameters including (ΔG°, ΔH°, and ΔS°) indicated that the adsorption of CV onto NC was an endothermic and spontaneous process.

International audience; The photodegradation of an industrial azo dye C.I Basic Red 46 was examined in a fixed-bed photoreactor using UV-lamps simulated to the solar irradiation. In our photodecolorization study, the UV/TiO2 process was optimized using the Box-Behnken approach to evaluate the synergistic effects of three independent parameters (initial concentration of the dye, flow rate, and UV intensity) on mineralization effectiveness. The response surface methodology was in good promise with the prediction model (coefficients of determination of decolorization and mineralization were R-Dec(2) = 0.997 and R-TOC(2) = 0.994, respectively). The effects of the factors could be estimated from a second-order polynomial equation and student's t-test. The optimal parameters of decolorization and mineralization were as follows: initial concentration of colorant 25 mg L-1, rate of fluid flow 0.3 L min(-1), and ultraviolet light intensity 38.1 W m(-2). The decolorization and mineralization removal efficiency under these optimal conditions were 100% and 57.63% respectively. These results indicate that optimization using response surface methodology, based on the Box-Behnken approach, is an excellent tool for determining the optimal conditions, and the process can be easily extrapolated for a specific treatment of real waste water containing the azo dye C.I Basic Red 46. Also, the intermediates that were produced during photodegradation process of Basic Red 46 were determined by GC/MS. (C) 2020 Published by Elsevier B.V. on behalf of King Saud University.

In this paper, we define an analytical index for a continuous family of Fredholm operators parameterized by a topological space $${\mathbb {X}}$$ into a Hilbert space H, as a sequence of integers, extending naturally the usual definition of the index and we prove the homotopy invariance of the index. We give also an extension of the Weyl theorem for normal continuous families and we prove that if H is separable, then the space of B-Fredholm operators on H is path connected.

This work focuses on the treatment of a dye solution, C.I. Basic Blue 41 (BB41), and industrial wastewater by UV/TiO2 photocatalytic process using aqueous catalyst suspensions of titanium dioxide (TiO2), Degussa P25. The procedures were carried out in a semi-pilot scale prototype solar photoreactor under solar radiation. Response surface methodology (RSM) based on Box-Wilson design was applied to assess individual effects of the five main independent parameters: initial dye concentration ([BB41]), TiO2 concentration ([TiO2]), flow rate (Q) initial pH and accumulated solar energy (Qvn) on the decolorization efficiency and to optimise the UV/TiO2 process. Photocatalytic mineralisation was carried out at the optimal conditions found by RSM and results were evaluated by total organic carbon (TOC) abatement for BB41 sloution and industrial wastewater. The optimal conditions found by RSM were: 0.4 g/L, 14.04 mg/L, 1,479.6 L/h, 5.52 and 80 KJ/L for TiO2 concentration, initial dye concentration, flow rate, initial pH and accumulated solar energy, respectively. Photocatalytic mineralisation results show that for accumulated visible solar energy equal to 377.714 kJ/L (after 6 hours of irradiation), under these conditions, the percentage of the initial TOC reduction is about 88% and 85.5% for industrial waste and BB41 solution, respectively.

Photodegradation of an industrial Azo dye C.I Basic Red 46, was examined in a semi-pilot scale prototype solar photoreactor under solar radiation. In our study, photodegradation of the dye was optimized using Response Surface Methodology (RSM) based on Box-Wilson approach. The Artificial Neural Network (ANN) was used to establish suitable modeling and optimal conditions for the Solar UV/Immobilized-TiO2 process in order to evaluate the individual effects of three factors that independently affect the effectiveness of the photodegradation process: (1) initial concentration of the dye, (2) pH, and (3) flow rate. The RSM was in good agreement with the prediction model (R2Dec = 0.95); meanwhile, the ANN approach revealed that the predicated model fit perfectly with the experimental data to yield the highest value of R2 = 0.999. The effects of these three factors could be estimated from a second-order polynomial equation, and the optimal parameters of photodegradation consisted of three main parameters: (1) initial concentration of colorant 10.65 mg.L−1, (2) pH 10.82, and (3) rate of fluid flow of 852 L h−1. The decolorization removal efficiency under these optimal conditions was 99%.

In this paper, we introduce the B-discrete spectrum of an unbounded closed operator and we prove that a closed operator has a purely B-discrete spectrum if and only if it has a meromorphic resolvent. After that, we study the stability of the B-discrete spectrum under several type of perturbations and we establish that two closed invertible linear operators having quasisimilar totally paranormal inverses have equal spectra and B-discrete spectra., Comment: 10 pages

The best exceptional Physico-chemical attributes of MXenes including high conductivity, high surface area, high functionalization, hydroxide site, and other interesting properties have attracted recently the attention of scientists in the applications of MXene (Mn+1XnTx)-based nanomaterials for water treatment. To provide a full and comprehensive vision of the current state of the art, and improve the treatment performance, and motivate new researches in this area, this review focused on the uses of these novel 2D transition metal carbides for desalination of water and the general methods of fabrication of MXenes; thus, MXene-based nanomaterials are very efficient candidates in water desalination processes, in this review, the main properties of previous and current works about MXenes applications in this area were properly investigated. Moreover, a particular overview about the different properties of MXenes in desalination such as etching method, hydrophobicity, structural modification, and chemical modification has been performed; meanwhile, the investigation of MXenes and MXenes-based composites would be an excellent candidate in the future of water purification and environmental remediation fields, since they have several good properties compared to the other 2D materials. Scopus

The photocatalytic degradation of pharmaceutical micropollutants of Penicillin G (PG) was investigated in a photoreactor at a laboratory scale. The impact of type of catalyst, pH, and initial concentration of PG were studied. Maximum removal efficiency was obtained at pH = 6.8, [ZnO]0 = 0.8 g L−1, and [PG]0 = 5 mg L−1 and reaction time of 150 min. The addition of persulfate sodium (PPS) enhanced the efficiency of the photocatalytic reaction. The efficiency of photolysis process in the presence of PPS was significantly improved to 72.72% compared to the classical photocatalysis system (56.71%). Optimum concentration of PPS to completely degraded PG was found to be 500 mg L−1. The QuEChERS extraction, GC-MS/MS method, and concentration technique showed favorable performance identification of the possible mechanism of PG degradation pathway. Toxicity of PG and its by-products were evaluated using microbioassays assessment based on nine selected bacterial strains. Results confirmed the effectiveness of the implemented system and its safe use via the bacteria Bacillus subtilis, which has illustrated significant activity. Due to the high efficiency, facility benefits, and low-cost of the suggested process, the process can be considered for the degradation of various pharmaceutical contaminants in pharmaceutical industry treatment under the optimal conditions.

The present work aims the synthesis of a novel, low cost, and environmentally friendly PANI/PVA-CuNi composite by chemical oxidative polymerization of aniline monomer and polyvinyl alcohol (PVA) as film matrix; several percentages of copper (Cu) and Nickel (Ni) were used. UV-Visible spectroscopy, FTIR, SEM-EDX, and TGA were used to characterize the nanocomposites. While PANI/PVA-CuNi nanocomposites were investigated in adsorption experiments of methylene blue (MB) under different controlled conditions (time reaction, adsorbent dosage, initial dye concentration, stirring speed, temperature, and pH of the medium) also various kinetic models were employed to evaluate the efficiency of the adsorption. The results revealed that the10 mg of PANI/PVA-Cu

Silver nanoparticles (AgNPs) are a promising technology for the design of antimicrobial agents against drug-resistant pathogens. It could also be used for the photocatalytic degradation of dyes used in industries such as methylene blue (MB). In this study, 17 different actinomycetal strains isolated from hydrocarbon-contaminated soils collected from an oil distribution company in Algeria were evaluated for their ability to produce NPs. After a selection process, S16 was the main strain capable of synthesizing AgNPs extracellularly. The strain S16 was determined using molecular identification based on the sequencing of the 16S rDNA gene. Among various techniques used for the synthesis of AgNPS, a technique using a temperature of 30 °C, pH of 7, a metal salt concentration of 1 mM, and a period of 72 h in the dark were found to be more effective in the biosynthesis of the AgNPs. The biosynthesized AgNPs that were analyzed by UV–visible spectroscopy resulted in a specific peak at a wavelength of (λ = 400 nm). The DRX analyses showed characteristic peaks of the AgNPs at (1 1 1), (2 0 0), (2 2 2), and (3 1 1), which validated the presence and crystalline nature of the biosynthesized NPs. Zetasizer analysis showed an average size and zeta potential of 64 nm (−32.3 mV), while the SEM-EDS analysis confirmed the spherical shape of AgNPs and the presence of Ag atoms in the elemental composition. The biosynthesized AgNPs indicated adequate antibacterial activity against 5 out of the 6 strains tested in this study, using minimum inhibitory concentration (MIC) that ranged from 217.18 μg/mL to 1137.5 μg/mL. The AgNPs were combined with commercial antibiotics and the synergistic effect of the combination was also assessed against MRSA which resulted in increased antibacterial activity of AgNPs in the presence of the strain S16. Furthermore, the photocatalytic degradation of the methylene blue (MB) was evaluated under sunlight and UV irradiations using biosynthesized AgNPs. The AgNPs showed photocatalytic decolorization potential of 71.3% for MB dye (20 ppm) under sunlight irradiation within 6 h of incubation, while only 11.25% of the MB dye degraded using UV irradiation.

Since the discovery of MXenes at Drexel University in the United States in 2011, there has been extensive research regarding various applications of MXenes including environmental remediation. MXenes with a general formula of Mn+1XnTx are a class of two-dimensional (2D) transition metal carbides, carbonitrides, and nitrides with unique chemical and physical characteristics as nanomaterials. MXenes feature characteristics such as high conductivity, hydrophobicity, and large specific surface areas that are attracting attention from researchers in many fields including environmental water engineering such as desalination and wastewater treatment as well as designing and building efficient sensors to detect hazardous pollutants in water. In this study, we review recent developments in MXene-based nanocomposites for electrochemical (bio) sensing with a particular focus on the detection of hazardous pollutants, such as organic components, pesticides, nitrite, and heavy metals. Integration of these 2D materials in electrochemical enzyme-based and affinity-based biosensors for environmental pollutants is also discussed. In addition, a summary of the key challenges and future remarks are presented. Although this field is relatively new, future research on biosensors of MXene-based nanocomposites need to exploit the remarkable properties of these 2D materials.

In this paper we define an analytical index for continuous families of Fredholm and semi-Fredholm operators parameterized by a topological space $$\mathbb {X}$$ into a Banach space X. As an application we study the continuity of the Weyl spectrum for continuous families of bounded linear operators. Moreover, we consider various regularities and semiregularities of continuous families of bounded linear operators.

Azithromycin (AZM), an antibacterial considered one of the most consumed drugs, especially during the period against the Covid 19 pandemic, and it is one of the persistent contaminants that can be released into aquatic ecosystems. The purpose of this study is to determine the efficacy of a Fenton-like process (chlorine/iron) for the degradation of AZM in an aqueous medium by determining the impact of several factors (the initial concentration of (FeSO

Conductive crystalline polypyrrole (Cryst-PPy), Nickel-polypyrrole (Ni-PPy), and copper- polypyrole (Cu-PPy) hybrid materials were prepared using a chemical polymerization method in an aqueous solution. Part I was focused on the Chemical synthesis of Cryst-PPy powder from an organic medium. Cryst-PPy powder was successfully synthesized by chemical route from an organic medium of acetonitrile with polyethylene oxide as a stabilizing agent and oxidizing agent like potassium peroxydisulfate. The morphological study was showed the presence of spherical nanoparticles and cubic microparticles giving rise to a denser structure of PPy. In the second part, the based electrodes composites were examined in the oxidation of phenol by an electrochemical process in an alkaline medium. To follow the yield of phenol degradation at the alkaline solution, UV–visible analysis was performed at the following operating conditions: current density of 0.58 mA cm−2, phenol initial concentration of 0.150 M and for 3 h processing; the rate of phenol elimination was 56%, 38% and 28% for Cu-PPy, Ni-PPy, and pure PPy electrodes respectively. Thus, can be found that the doped Cu-PPy electrodes electrode is a new material with high electrochemical oxidation ability for phenol degradation in aqueous solutions.

In this paper, the heterogeneous Fenton like-reaction for Arsenic-contaminated groundwater remediation based on the performance of FeSO4 as an efficient and green catalyst and CaO2 as a source of H2O2 was investigated. To intensify the heterogeneous Fenton process, three oxidants were tested: sodium percarbonate (SPC), sodium persulfate (SPS), and calcium peroxide (CP). The results showed that CP and SPC had a synergetic effect on the rate of Arsenic degradation, while SPS had an antagonistic effect. On the other hand, inorganic ions such as Na+, Mg2+ have a very low impact on the Arsenic removal efficiency, while the anions Cl− and NO3− exhibited significant inhibition of Arsenic degradation. This effect may be imputed to the reaction and conversion of hydroxyl (HO•) radicals to less reactive. Thus, HCO3− and humic acid dramatically raised the degradation rate. Also, the response Surface method based on Box-Behnken design was applied to examine the suitable modeling, and optimized condition of the Fenton like-reaction process, the maximum Arsenic removal efficiency of 94.91% is obtained when [Fe3+]0 = 1.97 mM, [CaO2]0 = 1.74 mM and initial pH = 4.67. The obtained results showed that the Fenton-like reaction is an effective and reliable process for arsenic removal from groundwater with low non-carcinogenic risk (HQ) and carcinogenic risk (CR) values.

In this paper we study operators originated from semi-B-Fredholm theory and as a consequence we get some results regarding boundaries and connected hulls of the corresponding spectra. In particular, we prove that a bounded linear operator T acting on a Banach space, having topological uniform descent, is a BR operator if and only if 0 is not an accumulation point of the associated spectrum $$\sigma _\mathbf{R}(T)=\{\lambda \in \mathbb {C}:T-\lambda I\notin \mathbf{R}\}$$ , where $$\mathbf{R}$$ denote any of the following classes: upper semi-Weyl operators, Weyl operators, upper semi-Fredholm operators, Fredholm operators, operators with finite (essential) descent and $$\mathbf{BR}$$ the B-regularity associated to $$\mathbf{R}$$ as in Berkani (Studia Mathematica 140(2):163–174, 2000). Under the stronger hypothesis of quasi-Fredholmness of T, we obtain a similar characterisation for T being a $$\mathbf{BR}$$ operator for much larger families of sets $$\mathbf{R}.$$

We define here a pseudo B-Fredholm operator as an operator such that 0 is isolated in its essential spectrum, then we prove that an operator T is pseudo-B-Fredholm if and only if T = R + F where R is a Riesz operator and F is a B-Fredholm operator such that the commutator [R,F] is compact. Moreover, we prove that 0 is a pole of the resolvent of an operator T in the Calkin algebra if and only if T = K + F, where K is a power compact operator and F is a B-Fredholm operator, such that the commutator [K,F] is compact. As an application, we characterize the mean convergence in the Calkin algebra.

This study underlines the biotechnical valorization of the accumulated and unusable remains of agro-industrial orange fruit peel waste to produce α-amylase under submerged conditions by Streptomyces sp. KP314280 (20r). The response surface methodology based on central composite design (RSM-CCD) and artificial neural network coupled with a genetic algorithm (ANN-GA) were used to model and optimize the conditions for the α-amylase production. Four independent variables were evaluated for α-amylase activity including substrate concentration, inoculum size, sodium chloride powder (NaCl), and pH. A ten-fold cross-validation indicated that the ANN has a greater ability than the RSM to predict the α-amylase activity (R2ANN = 0.884 and R2RSM = 0.725). The analysis of variance indicated that the aforementioned four factors significantly affected the α-amylase activity. Additionally, the α-amylase production experiments were conducted according to the optimal conditions generated by the GA. The results indicated that the amylase yield increased by 4-fold. Moreover, the α-amylase production (12.19 U/mL) in the optimized medium was compatible with the predicted conditions outlined by the ANN-GA model (12.62 U/mL). As such, the ANN and GA combination is optimizable for α-amylase production and exhibits an accurate prediction which provides an alternative to other biological applications.

Pesticides are chemical compounds used to kill pests and weeds. Due to their nature, pesticides are potentially toxic to many organisms, including humans. Among the various methods used to decontaminate pesticides from the environment, the heterogeneous photocatalytic process is one of the most effective approaches. This study focuses on artificial intelligence (AI) techniques used to generate optimum predictive models for pesticide decontamination processes using heterogeneous photocatalytic processes. In the present study, 537 valid cases from 45 articles from January 2000 to April 2020 were filtered based on their content collected and analyzed. Based on cross-industry standard process (CRISP) methodology, a set of four classifiers were applied: Decision Trees (DT), Bayesian Network (BN), Support Vector Machines (SVM), and Feed Forward Multilayer Perceptron Neural Networks (MLP). To compare the accuracy of the selected algorithms, accuracy, and sensitivity criteria were applied. After the final analysis, the DT classification algorithm with seven factors of prediction, the accuracy of 91.06%, and sensitivity of 80.32% was selected as the optimal predictor model. Scopus

This article was focused on the elaboration of NiFe-Polyaniline glucose sensors via electrochemical technique. Firstly, the PANi (polyaniline) fibers were synthesized by oxidation of the monomer aniline on FTO (fluorine tin oxide) substrate. Secondly, the Nickel–Iron nanoparticles (NiFe (NPs)) were obtained by the Chronoamperometry method on the Polyaniline surface. The NiFe-PANi hybrid electrode was characterized by scanning electron microscopy (SEM), force atomic microscopy (AFM), Fourier-transformed infrared (FTIR), and X-ray diffraction (XRD). The electrochemical glucose sensing performance of the NiFe alloy nanoparticle was studied by cyclic voltammetry and amperometry. The fabricated glucose sensor Ni–Fe hybrid material exhibited many remarkable sensing performances, such as low-response time (4 s), sensitivity (1050 μA mM−1 cm−2), broad linear range (from 10 μM −1 mM), and low limit of detection (LOD) (0.5 μM, S/N = 3). The selectivity, reliability, and stability of the NiFe hybrid material for glucose oxidation were also investigated. All the results demonstrated that the NiFe-PANi/FTO hybrid electrode is very promising for application in electrochemical glucose sensing.

Increasing antimicrobial resistance has led to use of novel technologies such as nanomaterials and nanocomposites that have shown effective antimicrobial and/or antifungal activities against several gram-positive and gram-negative bacteria. There have been limited studies on antimicrobial properties of the combined polymer nanocomposites with transitional bimetallic nanoparticles such as nickel (Ni) and copper (Cu). Thus, the main objective of this study was to synthesis, characterize and investigate the antibacterial and antifungal properties of NiCu-PANI/PVA nanocomposite. The nanocomposite films with different amount of Ni and Cu salts were synthesized by chemical oxidative polymerization of polyaniline using HCl as oxidant and PVA as a stabilizer. Optical, chemical composition, and morphological characteristics as well as thermal stability were evaluated using UV–Visible, FTIR, SEM-EDX, and TGA analyses. Antimicrobial properties were then determined using the disc diffusion assay against gram-negative bacteria (i.e., Escherichia coli ATCC 25922, Klebsiella pneumonia ATCC 700603, Proteus sp.,) and gram-positive bacteria (i.e., Staphylococcus aureus ATCC 2593). Fungal plant pathogens including Aspergillus niger and Fusarium oxysporum f. sp. pisi were also evaluated for determination of antifungal activity of NiCu-PANI/PVA films. Among the synthesized films, Ni65Cu35-PANI/PVA showed excellent antibacterial activity against all the bacteria strains examined in this study. The diameters of inhibition zones for Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 700603, Proteus sp., and Staphylococcus aureus ATCC 2593 were 23, 23, 17, and 18 mm, respectively indicating good antibacterial activities. Additionally, NiCu-PANI/PVA, particularly the films with higher Cu intake, showed better antifungal activity against Fusarium oxysporum f. sp. pisi. However, NiCu-PANI/PVA was ineffective against Aspergillus niger.

The present work investigates for the first time the presence and isolation of the thermophilic fungi from hydrothermal spring situated at the locality of Guelma, in the Northeast of Algeria. The production of the thermostable proteases and the optimization of culture conditions under agro-wastes solid-state fermentation to achieve optimal production capacity were explored. A statistical experimental approach consisting of two designs was used to determine the optimum culture conditions and to attain the greatest enzyme production. Besides, different agricultural wastes were initially evaluated as a substrate, whereby wheat bran was selected for enzyme production by the isolate under solid-state conditions. The isolate thermophilic fungi were identified as Mycothermus thermophilus by sequencing the ITS region of the rDNA (NCBI Accession No: MK770356.1). Among the various screened variables: the temperature, the inoculum size, and the moisture were proved to have the most significant effects on protease activity. Employing two-level fractional Plackett–Burman and a Box–Behnken designs statistical approach helped in identifying optimum values of screened factors and their interactions. The analysis showed up 6.17-fold improvement in the production of proteases (~1187.03 U/mL) was achieved under the optimal conditions of moisture content 47%, inoculum 5 × 105 spores/g, and temperature at 42 °C. These significant findings highlight the importance of the statistical design in isolation of Mycothermus thermophilus species from a specific location as well as identifying the optimal culture conditions for maximum yield.

In this paper we define B-Fredholm elements in a Banach algebra $A$ modulo an ideal $J$ of $A.$ When a trace function is given on the ideal $J,$ it generate an index for B-Fredholm elements. In the case of a B-Fredholm operator $T$ acting on a Banach space, we prove that its usual index $ind(T)$ is equal to the trace of the commutator $ [T, T_0],$ where $T_0$ is a Drazin inverse of $T$ modulo the ideal of finite rank operators, extending a Fedosov's trace formula for Fredholm operators. In the case of a semi-simple Banach algebra, we prove a punctured neighborhood theorem for the index., Comment: 7 pages

International audience; This study focused on electrocoagulation treatment of leachate effluent using aluminum electrodes in a discontinuous system, the modeling and optimization of which were carried out using the response surface methodology (RSM) basing on the central composite design (CCD). Moreover, individual and interaction effects of principal independent factors (current density (X1), initial pH (X2), electrolysis time (X3), and distance between electrodes (X4)), on chemical oxygen demand (COD) removal efficiency response, were investigated. The obtained results were in good agreement with the predicted ones with correlation factors R2 Dec = 0.94 and R2 Ajusted = 0.88. At the optimal conditions, maximal removal efficiency was achieved for values of chemical oxygen demand (COD), total organic carbon, total nitrogen, and turbidity of 79.8%, 78%, 45.4%, and 99.9%, respectively. The quite good agreement between the experimental values and the predicted results confirms the reliability of the RSM approach in the modeling and optimizing of the leachate treatment using an electrocoagulation process. © 2018 Desalination Publications. All rights reserved.

As good quality water is becoming increasingly scarce, efficient methods for water recovery, recycling, and reuse must be developed to ensure a reliable water supply. This endeavor may take into account other water supplies such as sea and wastewater. Due to its unique structure and excellent physical and chemical properties, graphene and its derivatives are appealing for a variety of applications, including pollutant removal and water desalination. The graphene-based membranes (GBMs) displayed extremely high molecular separation and mass-transport properties, as well as antifouling properties that are not found in the existing state-of-art commercial membranes. As such, there is a huge potential for technology disruption. The present paper reviews the latest developments, discoveries, and prospective applications related to graphene-based membranes with an in-depth focus on heavy metal removal. The review offers a summary and outlook on the opportunities and challenges in this arising field. It was observed that GBM techniques are capable of producing large, leak-free, and fouling-free membranes that have a promising potential for the removal of hazardous pollutants from water.

In this paper, the influence of several aquatic factors (the nature of catalyst, the initial pH and the initial concentration of the pollutant) on the photocatalytic degradation of diclofenac (DFC), one of the most widely prescribed anti-inflammatory non-steroidal drug, was studied. Also, in order to examine the intensification process, the variation of the photocatalytic DFC degradation in the presence of sodium persulfate (PPS) was analyzed. It was found that, compared to titanium dioxide (TiO2), the zinc oxide (ZnO) photocatalyst performed exceptionally well, with a 96.13% DFC degradation efficiency after 150 min. The photodegradation of DFC by ZnO catalyst fitted well the Langmuir–Hinshelwood kinetic model. The maximum efficiency is 97.27% for simulated solar-UVA/ZnO/PPS and 77% for simulated solar-UVA/ZnO. In order to determine the optimal conditions leading to the maximization of DFC removal, an artificial neural network (ANN) modeling approach combined with genetic algorithm (GA) was applied. The best ANN determined had a correlation of 0.999 and it was further used in the process optimization where a 99.7% degradation efficiency was identified as the optimum under the following conditions: DFC initial concentration 37,9 mg L−1, pH 5,88 and PPS initial concentration 500 mg L−1. The effectiveness of the process and the toxicity of the pharmaceutical pollutants and their by-products were also evaluated and confirmed by the biological tests using liver and kidney of Mus musculus mice.

In this paper, we study B-Fredholm spectral properties of an invertible closed linear operator in relation with the B-Fredholm spectral properties of its bounded inverse. Precisely, for such operator, we characterize its B-Fredholm spectrum and other related spectra in terms of the corresponding spectra of its bounded inverse. As an application, we show that every normal operator with nonempty resolvent set, in particular self-adjoint Schrodinger operators, satisfies generalized Weyl’s theorem.

In this paper we introduce and study the new properties (W �), (UWa), (UW E) and (UW �). The main goal of this paper is to study relationship between these new properties and other Weyl type theorems. Moreover, we reconsider several earlier results obtained respec- tively in (11), (18), (14), (1) and (13) for which we give stronger versions. by σa(T) the approximate point spectrum of T. If the range R(T) of T is closed and α(T) < ∞ (resp. β(T) < ∞), then T is called an upper semi-Fredholm (resp. a lower semi-Fredholm) operator. If T ∈ L(X) is either upper or lower semi Fredholm, then T is called a semi-Fredholm operator, and the index of T is defined by ind(T) = α(T) − β(T). If both of α(T) and β(T) are finite, then T is called a Fredholm operator. An operator T ∈ L(X) is called a Weyl operator if it is a Fredholm operator of index zero. The Weyl spectrum σW(T) of T is defined by σW(T) = {λ ∈ C | T − λI is not a Weyl operator}. For a bounded linear operator T and a nonnegative integer n, define T(n) to be the restriction of T to R(T n ), viewed as a map from R(T n ) into R(T n ) (in particular T(0) = T). If for some integer n the range space R(T n ) is closed and T(n) is an upper (resp. a lower) semi-Fredholm operator, then T is called an upper (resp. a lower) semi-B-Fredholm operator. A semi-B-Fredholm operator T is an upper or a lower semi-B-Fredholm operator, and in this case the index of T is defined as the index of the semi-Fredholm operator T(n), see (12). Moreover if T(n) is a Fredholm operator, then T is called a B-Fredholm operator, see

BACKGROUND The photocatalytic decolorization of C.I. Basic blue (BB41) in aqueous catalyst suspensions of titanium dioxide (TiO2), Degussa P25, was carried out in a semi-pilot scale prototype solar photoreactor equipped with compound parabolic collectors (CPCs). The experiments on the solar reactor were performed with and without collectors. Response surface methodology (RSM) was applied to assess individual and interactive effects of the four main independent parameters (initial dye concentration, TiO2concentration, flow rate and initial pH) on the decolorization efficiency, the central composite design (CCD) was used for optimization of UV/TiO2 process. RESULTS The presence of the collectors has increased the rate of decolorization of 50% for an initial dye concentration of 40 mg L−1 and after 80 kJ L−1 of visible energy accumulated. Predicted values of decolorization efficiency according to RSM were in close agreement with the experimental values (R2 = 0.9626, Adj-R2 = 0.9252). Optimization results showed that maximum decolorization efficiency was achieved at the optimum conditions catalyst concentration 0.577 g L−1, initial dye concentration 17.933 mg L−1, flow rate 1446.8 L h−1 and initial pH 4.6 for 60 kJ L−1 of VIS energy accumulated. CONCLUSION The photocatalytic decolorization of a textile dye, C.I. Basic Blue 41, in a tubular solar prototype photoreactor was optimized. Response surface methodology based on the central composite design has been shown to be a powerful tool in the development of any photocatalytic process due to its impact on the economy and practicability of the process. © 2014 Society of Chemical Industry

In this paper, we study the stability of extended Weyl and Browdertype theorems for orthogonal direct sum S⊕T, where S and T are bounded linear operators acting on Banach space. Two counterexamples shows that property (ab), in general, is not preserved under direct sum. Nonetheless, and under the assumptions that Π0α (T) ⊂σα(S) and Π0α(S) ⊂σα(T), we characterize preservation of property (ab) under direct sum S⊕T. Furthermore, we show that if S and T satisfy generalized a-Browder’s theorem, then S⊕T satisfies generalized a-Browder’s theorem if and only if σSBF-+ (S ⊕T) = σSBF-+(S) ∪σSBF-+(T), which improves a recent result of [13] by removing certain extra assumptions.

We introduce and we study the new spectral properties (SBw), (SBaw), (SBab) and (SBb). Among other results, we show that if T is a bounded linear operator acting on a Banach space X, then T possesses property (SBb) if and only if T possesses property (b) and � 0 (T) = �a(T).

The aim of this paper is to give an extended version of the Fredholm alternative, by including the B-Fredholm case. Thus if T a B-Fredholm operator acting on a Banach space, we study equations of the type T(x) = y, for x, y elements of the range R(Tn) of T for \({n \in \mathbb{N}}\). In this study we include the case when 0 is a pole of infinite rank of the resolvent of T. Preliminarily, we define unbounded closed B-Fredholm operators on Banach spaces.

In this paper, we study B-Fredholm elements in rings and algebras. After characterising these elements in terms of generalized Fredholm elements, we will give a condition on the socle of a unital primitive Banach algebra $A$, under which we prove that an element of $A$ is a B-Fredholm element of index $0$ if and only if it is the sum of a Drazin invertible element of $A$ and an element of the socle of $A$., 11 pages

The aim of this paper is to study the Weyl type-theorems for the orthogonal direct sum S T, where S and T are bounded linear operators acting on a Banach space X. Among other results, we prove that if both T and S possesses property (gb) and if ( T) a(S), ( S) a(T), then S T possesses property (gb) if and only if SBF+ (S T) = SBF+ (S)( SBF+ (T). Moreover, we prove that if T and S both satises generalized Browder's theorem, then S T satises generalized Browder's theorem if and only if BW(S T) = BW(S) ( BW(T).

We study the new properties (b) and (gb), which we had introduced in [13], for an operator having the SVEP on the complement of distinguished parts of its spectrum. Classes of operators are considered as illustrating examples.

In [9], we introduced the properties (b) and (gb), which are analogous of Browder and generalised Browder theorems. In this paper we study the stability of properties (b) and (gb) under commutative perturbations by finite rank, compact and nilpotent operators. Among other results, we prove that if T is an operator acting on a Banach space and possesses property (b) and N is a nilpotent operator commuting with T, then T + N possesses property (b). The same result holds for property (gb) in the case of a-polaroid operators.