Search

A method to assemble 2‐aminobenzoxazoles via iron‐catalyzed redox condensation of amines, carbon disulfide and 2‐nitrophenols is reported. The reaction features advantages of environmentally friendly iron catalyzed conditions, readily available starting materials, and excellent atom‐, step‐ and redox‐ economy compared to known protocols. Experimental investigation suggests a mechanism encompassing iron‐catalyzed reduction of the nitro group of 2‐nitrophenols by the dithiocarbamate group from amine‐CS2 adduct. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Advances in Engineering & Pure Sciences is the property of Marmara University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Metal and metal oxides nanoparticles (NPs) supported on polymer nanocomposites have recently received significant attention due to their valuable applications in catalysis. In this work, cellulose acetate butyrate/TiO2 (CAB/TiO2) and CAB/TiO2/Au nanocomposite films were fabricated via a nanosecond pulsed laser ablation method in liquid. The obtained nanocomposites were characterized by UV–Vis spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). These techniques confirmed the formation of CAB/TiO2 and CAB/TiO2/Au nanocomposites. The catalytic performance of the fabricated nanocomposites was evaluated in the reduction of 2-nitrophenol (2-NP) to 2-aminophenol in the presence of sodium borohydride (NaBH4) as a reducing agent and quantitively was monitored by UV–Vis spectroscopy. The obtained results showed an excellent catalytic activity of the CAB/TiO2/Au nanocomposites, as 8 mg of the catalyst load resulted in ~ 100% conversion within a reaction time of 16 min. The reduction reaction of 2-NP follows the pseudo-first-order model, with rate constants of 0.0148, 0.0299, and 0.803 min−1 for 1 mg, 4 mg, and 8 mg catalysts loadings respectively. Moreover, the fabricated nanocomposites showed high stability and reusability, as it has been reused for the reduction of 2-NP up to 5 cycles without significant loss in catalytic activity. [ABSTRACT FROM AUTHOR]

Derivative processing of the signal obtained by differential pulse voltammetry was applied in this work as a simple strategy to achieve the sensitive and selective 4‐nitrophenol (4‐NP) determination in the presence of the interfering compound 2‐nitrophenol (2‐NP). The derivative voltammogram displayed a well‐defined and fully separated 4‐nitrophenol anodic peak, which was used for its quantification in two linear concentration ranges extended up to 10 μmol L−1 and up to 100 μmol L−1. A LOD as low as 0.1 μmol L−1 (S/N=3) was achieved using spectroscopic graphite electrode without any modification. The accuracy of the 4‐NP determination in the presence of 2‐NP, assessed by spike‐and‐recovery experiments was found to be satisfactory. 4‐NP determination was not affected by the presence of a range of structurally similar phenolic compounds. [ABSTRACT FROM AUTHOR]

Contamination of water and food with cyanotoxins poses human health risks, and hence the need for sensitive early warning tools to monitor these in water. A composite of glutaraldehyde-crosslinked chitosan and multi-walled carbon nanotubes (ChMWCNTs) was synthesised and tested for potential use as a solidphase adsorption toxin tracking (SPATT) adsorbent for monitoring microcystins (MCs) in fresh water. The composite was characterised by Fourier transform infrared spectroscopy, Brunauer--Emmett--Teller theory and scanning electron microscopy. Batch adsorption experiments to assess the effect of contact time, adsorbent dosage and initial microcystin-LR (MC-LR) concentration were conducted. The composite was found to be efficient in adsorbing MC-LR, showing 97% removal and a maximum adsorption capacity of 4.639 µg/g under optimised conditions of 5 µg/L of MC-LR, adsorbent dose of 0.03 g/5 mL and 30 min contact time. The adsorption kinetics were better explained by a pseudo-second-order model, inferring chemisorption adsorption. The isotherm data better fitted the Langmuir isotherm model, thus inferring monolayer surface adsorption. For desorption, 100% methanol was the most effective, with an efficiency of 84.71%. The composite effectively adsorbed and desorbed three congeners of MCs (--LR, --RR and --YR) when tested in raw dam water, regardless of its lower maximum adsorption capacity compared to those of other adsorbents used for similar purposes. [ABSTRACT FROM AUTHOR]

The pursuit of a cost-effective and green synthetic approach to chemical sensors and their application in the sensing of toxic and harmful substances is a never-ending exercise for scientists and researchers. Preparation of fluorescent carbon dots (C-dots) from biomass using water as a solvent and a hydrothermal autoclave to provide the required synthesis temperature offers a cheap and environmentally friendly synthetic approach. Herein, we report a faster, less costly and ecofriendly hydrothermal synthetic approach of carbon dots from Citrullus vulgaris peels as a precursor. The as-prepared carbon dots exhibited hydroxyl, carbonyl and amide functional groups on the surface and an amorphous structure with a particle size distribution of 1.7-3.0 nm. Moreover, the carbon dots displayed intense blue emission fluorescence at 470 nm after excitation at 400 nm. The as-prepared carbon dots demonstrated effective application without further modification towards the selective and sensitive optical recognition of 2-nitrophenol used in the manufacture of explosives. A limit of detection of 2.28x10-7 M was achieved, and no fluorescence quenching was observed in the presence of other nitroaromatic and benzene derivatives indicating excellent selectivity towards 2-nitrophenol. Finally, further studies are required to investigate the potential for the as-prepared carbon dots to monitor nitroaromatic pollutants in real environmental systems. [ABSTRACT FROM AUTHOR]

Environmental contamination has become the most pressing issue in recent years. The value of clean water to mankind has sparked interest in heterogeneous photocatalysis. In this study, a novel photocatalyst has been synthesized by integrating WO3-doped MoO3 (WDM) and ZnO through composite formation. The composite nature of the synthesized photocatalyst was confirmed due to the presence of hexagonal ZnO and orthorhombic WDM phases in XRD pattern and scanning electron micrographs. Solid-state absorption spectra and a bandgap analysis showed that WDM-spectral ZnO's response was better than that of pure ZnO. PL and EIS unveiled the effective role of WDM in suppressing the e−–h+ recombination process and charge-transfer resistance, respectively, in ZnO. The photocatalytic studies showed that WDM-ZnO was able to remove ~90% of 30 ppm 2-nitrophenol (2-NP) with a rate of 1.1 × 10−2 min−1, whereas ~65% 2-NP was removed by ZnO (6.1 × 10−3 min−1 rate) under the exposure of natural sunlight (800 × 102 ± 100 lx). Moreover, ~52% higher total organic carbon (TOC) removal was observed by WDM-ZnO as compared to ZnO. The photocatalytic removal of 2-NP by the produced photocatalysts followed the Langmuir–Hinshelwood kinetic model, as shown by the kinetic studies. The reactive oxygen species (ROS)-trapping established that the photocatalytic removal mechanism of 2-NP over WDM-ZnO in sunlight illumination was mainly triggered by the superoxide anion (O2•−) radical, however, the minor role of hydroxyl (•OH) radicals cannot be completely ignored. [ABSTRACT FROM AUTHOR]

The green synthesis of metallic nanoparticles is essential to a broad range of environmental applications. In this work, one-step green synthesis of colloidal Au, Au–Ag and Au–Cu nanoparticles with polyhedral shape and their use as catalysts for the reduction of 2-nitrophenol are reported. In our method, poly(p-acryloylaminophenylarsonic acid) (poly(p-AAPHA) was used as reducing and stabilizing agent for the synthesis of metal nanoparticles in aqueous solutions at room temperature and without using hazardous chemicals. Polyhedral nanoparticles were characterized by ultraviolet–visible (UV–Vis) spectroscopy and transmission electron microscopy (TEM). UV–Vis results revealed that the reduction process of metallic ions by poly(p-AAPHA) occurs slowly, and the formation of nanoparticles take place after several days. The nanoparticles were stabilized in the colloidal solutions by the combination of steric and electrostatic effects provided by poly(p-AAPHA). TEM images confirmed the polyhedral shape of the Au, Au–Ag and Au–Cu nanoparticles with an average size of 18.2, 18.4 and 22 nm, respectively. Also, the Au–Ag and Au–Cu particles showed a structure homogeneous alloy type. The study of the reduction of 2-nitrophenol in aqueous solution in presence of sodium borohydride using the poly(p-AAPHA)-stabilized polyhedral nanoparticles as catalyst revealed that their catalytic activity is dependent on the composition and particle size. Polyhedral Au nanoparticles showed the highest reaction rate constant 0.188 min−1 followed by Au–Ag (0.0729 min−1) and Au–Cu (0.016 min−1). [ABSTRACT FROM AUTHOR]

The pursuit of a cost-effective and green synthetic approach to chemical sensors and their application in the sensing of toxic and harmful substances is a never-ending exercise for scientists and researchers. Preparation of fluorescent carbon dots (C-dots) from biomass using water as a solvent and a hydrothermal autoclave to provide the required synthesis temperature offers a cheap and environmentally friendly synthetic approach. Herein, we report a faster, less costly and ecofriendly hydrothermal synthetic approach of carbon dots from Citrullus vulgaris peels as a precursor. The as-prepared carbon dots exhibited hydroxyl, carbonyl and amide functional groups on the surface and an amorphous structure with a particle size distribution of 1.7–3.0 nm. Moreover, the carbon dots displayed intense blue emission fluorescence at 470 nm after excitation at 400 nm. The as-prepared carbon dots demonstrated effective application without further modification towards the selective and sensitive optical recognition of 2-nitrophenol used in the manufacture of explosives. A limit of detection of 2.28×10−7 M was achieved, and no fluorescence quenching was observed in the presence of other nitroaromatic and benzene derivatives indicating excellent selectivity towards 2-nitrophenol. Finally, further studies are required to investigate the potential for the as-prepared carbon dots to monitor nitroaromatic pollutants in real environmental systems. Significance: • Terrorism is an ever-increasing problem, and law enforcement agencies are continuously searching for and detecting explosives hidden in travel luggage, mail packages, vehicles and aircrafts using sophisticated equipment which are not available in developing countries such as Botswana. • This work unveils a facile and environmentally friendly approach towards the detection of 2-nitrophenol used in the manufacture of explosives by employing highly luminescent C-dots obtained from locally available agricultural waste. • The utilisation of agricultural waste can help advance a sustainable waste management programme and promote a circular economy.

This work reports an effective laser synthesis of CuO nanoparticles, seeded in cellulose acetate butyrate (CAB). The structure and composition of the resulting nanocomposite were confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Uv–visible spectroscopy, Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Raman spectroscopy and Fourier transform infrared spectrometry (FTIR). The characterization data showed that incorporating CuO into the CAB polymer matrix resulted in a heterogeneous organic–inorganic nanocomposite framework, such that suppressed crystallinity, decreased thermostability, and favorably reduced bandgap energy were seen in the CAB/CuO nanocomposite relative to the CAB material itself. The fabricated CAB/CuO nanocomposite was then successfully applied in the reduction of 2-nitrophenol (2-NP), a common organic pollutant in wastewater, where even low concentrations are harmful to human health and aquatic life. The reduction of the 2-nitrophenol compound was carefully monitored by UV–visible absorption spectroscopy. This revealed an apparent rate constant of 0.248 s−1 for the reduction process, demonstrating an excellent catalytic performance by the cellulose acetate butyrate film/CuO nanocomposite. In the technique reported, the reduction efficiency is a factor of time, with 100% efficiency achieved in 16 min. [ABSTRACT FROM AUTHOR]

The creation of S-scheme heterostructures can overcome the problems of low carrier separation efficiency and reduced redox ability in traditional photocatalysis, and therefore has a wide range of applications in environmental remediation. In this work, a novel highly dispersed Perylene diimide nanoparticles encapsulated BiVO 4 nanosheets S‐scheme heterostructure (PTCDI@BVO) was constructed using a simple hydrothermal technique for 2-nitrophenol degradation under visible light irradiation. The optimum 0.3%PTCDI@BVO can degrade 81.06 % of 2-nitrophenol within 2 h and presented a high apparent rate constant (0.01413 min−1), which was respectively 14 and 1.8 times higher than that of pristine PTCDI (0.00101 min−1) and BiVO 4 (0.00784 min−1). Meanwhile, the optimum sample also demonstrated good cycling performance over five cycles. By adding 200 μL of H 2 O 2 , the 2-nitrophenol degradation efficiency can be increased to 96.61 %. Moreover, h+ was the primary contributor to the degradation process, followed by •O2− and •OH through the active species trapping tests. The superior photocatalytic activity of PTCDI@BVO has been ascribed to the built of S-scheme heterostructure between 0D PTCDI and 2D BiVO 4 , which accelerates the carrier transmission and separation efficiency. This study highlights a viable approach for designing and constructing high-performance organic/inorganic S-scheme heterostructures for multiple applications. [Display omitted] • PTCDI@BiVO 4 heterostructure was constructed via a facile hydrothermal method. • PTCDI nanoparticles are highly dispersed and encapsulated on surface of 2D BiVO 4. • 0.3%PTCDI@ BiVO 4 exhibits superior activity compared to BiVO 4 and PTCDI. • PTCDI@BiVO 4 heterostructure follows the S-scheme photocatalytic mechanism. • h+ is the main active specie in the photo-degradation of 2-nitrophenol. [ABSTRACT FROM AUTHOR]

A simple and fast electrochemical method based on aminoalcohol‐functionalized palm oil fiber modified carbon paste electrode (TEA‐POF/CPE) has been used for the electroanalysis of 2‐nitrophenol (2‐NP). The aminoalcohol‐functionalized palm oil fiber (TEA‐POF) was prepared by chemical grafting of triethanolamine (TEA) onto the surface of alkali material. The grafted material was characterized by some physico‐chemical techniques. The electrochemical results showed that the TEA‐POF/CPE exhibited more sensitive response towards the 2‐NP reduction and allowed to estimate a low detection limit of 1.26 μM (S/N=3). Finally, the sensor has been selective and successfully applied to the 2‐NP detection in real water samples. [ABSTRACT FROM AUTHOR]

Environmental contamination has become the most pressing issue in recent years. The value of clean water to mankind has sparked interest in heterogeneous photocatalysis. In this study, a novel photocatalyst has been synthesized by integrating WO3-doped MoO3 (WDM) and ZnO through composite formation. The composite nature of the synthesized photocatalyst was confirmed due to the presence of hexagonal ZnO and orthorhombic WDM phases in XRD pattern and scanning electron micrographs. Solid-state absorption spectra and a bandgap analysis showed that WDM-spectral ZnO’s response was better than that of pure ZnO. PL and EIS unveiled the effective role of WDM in suppressing the e−–h+ recombination process and charge-transfer resistance, respectively, in ZnO. The photocatalytic studies showed that WDM-ZnO was able to remove ~90% of 30 ppm 2-nitrophenol (2-NP) with a rate of 1.1 × 10−2 min−1, whereas ~65% 2-NP was removed by ZnO (6.1 × 10−3 min−1 rate) under the exposure of natural sunlight (800 × 102 ± 100 lx). Moreover, ~52% higher total organic carbon (TOC) removal was observed by WDM-ZnO as compared to ZnO. The photocatalytic removal of 2-NP by the produced photocatalysts followed the Langmuir–Hinshelwood kinetic model, as shown by the kinetic studies. The reactive oxygen species (ROS)-trapping established that the photocatalytic removal mechanism of 2-NP over WDM-ZnO in sunlight illumination was mainly triggered by the superoxide anion (O2•−) radical, however, the minor role of hydroxyl (•OH) radicals cannot be completely ignored.

Magnetic porous carbon composite was synthesized from zeolitic imidazolate framework (ZIF‐12) and used as a support material to fabricate CoPd nanoparticles decorated NPC@ZIF‐12 nanocatalyst. The structure of CoPd@NPC@ZIF‐12 has been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), Raman, Brunauer–Emmett–Teller (BET), X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and inductively coupled plasma mass spectrometry (ICP‐MS) techniques. The catalytic reduction reaction of nitrophenols (NP) to aminophenols (AP) was successfully achieved by CoPd@NPC@ZIF‐12 nanocatalyst. When the catalytic performance of the catalyst was compared with other reported catalysts, the performance of the catalyst and reusability was found much better. This better catalytic activity of the CoPd@NPC@ZIF‐12 nanocatalyst may be attributed to facilitating the mass transfer of the nitro compound and the wettability of catalyst caused by the high nitrogen content of the carbon matrix and to the synergistic effect of Co and Pd nanoparticles. The CoPd@NPC@ZIF‐12 nanocatalyst showed perfect catalytic activity in the reduction of 4‐nitrophenol (4‐NP), 3‐nitrophenol (3‐NP), and 2,4‐nitrophenol (2,4‐DNP) reactions with high turnover frequency (TOF) values of 1679, 2687, and 1014 h−1, respectively. The reusability experiments of the CoPd@NPC@ZIF‐12 nanocatalyst showed that the catalytic activity of the CoPd@NPC@ZIF‐12 nanocatalyst was almost retained after 10 consecutive reaction runs. The SEM, XRD, and FTIR analyses of the 10 times used CoPd@NPC@ZIF‐12 nanocatalyst showed that there were limited changes in the structure of the CoPd@NPC@ZIF‐12 nanocatalyst. This highly active, magnetically separable, and recyclable CoPd@NPC@ZIF‐12 catalyst exhibits better catalytic activity than commercial Pd/C catalysts. [ABSTRACT FROM AUTHOR]

This article reports an unexploited method for the green synthesis of gold nanoparticles using Amaranthus tricolor leaves, with the aid of microwave assistance. The fresh leaf extract of the plant plays dual role in reducing and capping actions. The incorporation of microwave energy to this green approach overcomes the characteristic limitation of time consumption by the conventional green techniques. The synthesized gold nanoparticles are characterized using UV–vis., FT-IR, XRD, HR-TEM, EDX, DLS, and zeta potential analyses. The various functional groups in the plant extract which are responsible for the reduction and stabilization of nanoparticles were identified by FT-IR spectrum. The crystallographic peaks designated to face centered cubic lattice of the gold nanoparticles are evident from the XRD analysis. HR-TEM images illustrate the almost spherical morphology attained by the formed nanoparticles with an average particle diameter of 18.33 nm. The stability of nanoparticles is revealed by its zeta potential of − 21.3 mV. The DLS analysis results in a hydrodynamic diameter of 148.5 nm. The catalytic potential of the synthesized gold nanoparticles in the attenuation of harmful pollutants such as eosin Y and 2-nitrophenol by NaBH4 was studied. Both the catalytic degradations were successfully completed within few minutes of the reaction and they hold to pseudo-first order kinetics. The nanoparticles accomplished good antibacterial properties towards various bacteria and are demonstrated herein. Cytotoxic activity of the synthesized nanoparticles was evaluated for human lung cancer cell line A549 using MTT assay and a LC50 value of 102.39 ± 0.36 μg/mL was obtained. [ABSTRACT FROM AUTHOR]

Mixed oxides of Ni0.65Zn0.35Fe2O4 stoichiometry (Ni + Zn/Fe = 1:2) were prepared by citrate and coprecipitation methods, characterized by TGA-TD, XRD, FTIR and SEM, and its catalytic properties were investigated in hydrogenation of 2-nitrophenol (2-NP) to 2-aminophenol (2-AP) counterparts under ambient conditions. The methods of preparation influenced the textural, the structural and the reactivity properties. All the preparations show the presence of mixed phases containing spinel structure and γ-Fe2O3 oxide. The crystallite sizes increase with increasing calcination temperatures due to the coalescence of nanoparticles by solid-state diffusion. All samples exhibited high catalytic activity with first-order kinetic; the sample issued from citrate method and annealed at 800 °C (Ea ~ 31.6 kJ/mol) is the most active system with a high X-ray density and a low force constant at tetrahedral sites. For this catalyst, 99.7% of 2-NP was reduced to 2-AP within 6.5 min and the recycled catalyst shows a very good activity for five catalytic runs. It could remain more than 88% activity after it was used five times. [ABSTRACT FROM AUTHOR]

Copyright of Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım ve Teknoloji is the property of Gazi University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

2NP is among the priority pollutants for the environmental ecosystem and poses a threat to the health of living things by mixing in wastewater. Therefore, the 2NP determination is important. In this study, the glassy carbon (GC) electrode surface was modified with 1-amino-2-naphthol-4-sulfonic acid (ANSA). The electrochemical behavior and voltammetric determination of 2-nitrophenol (2NP) on the modified surface (ANSA-GC) was performed. Firstly, it was decided that the supporting electrolyte medium suitable for 2NP determination was Britton-Robinson (BR) buffer and the effect of pH change on the reduction peak of 2NP in this envi-ronment was investigated. The effect of changing scan rate on the reduction peak of 2NP was examined and this study showed that the reduction process of 2NP on the ANSA-GC modified electrode surface was diffusion controlled process. For 2NP determina-tion,two linear working ranges with two different slopes, 1.19×10-6-1.66×10-4 M and 1.66×10-4-1.14×10-3 M were obtained. LOD and LOQ values were calculated as 0.29 μM and 0.97 μM, respectively. Finally, lake water was used as the real sample, and 2NP was determined in this lake water. The experimental results showed that it can be used with a high accuracy and precision in the determination of 2NP with ANSA-GC modified electrode.

Copyright of Journal of South China Normal University (Natural Science Edition) / Huanan Shifan Daxue Xuebao (Ziran Kexue Ban) is the property of Journal of South China Normal University (Natural Science Edition) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The contamination of water with organic pollutants such as dyes and phenols is a serious environmental problem, requiring effective treatment methods. In the present study, a novel nanocomposite was synthesized by intercalating graphene oxide and bentonite clay into MgFeAl-layered triple hydroxide (GO/BENT/LTH), which was characterized using different techniques. The adsorption efficacy of the GO/BENT/LTH nanocomposite was assessed via the removal of two harmful organic water pollutants, namely methyl orange (MO) and 2-nitrophenol (2NP). The obtained results revealed that the maximum adsorption capacities (q max) of MO and 2NP reached 3106.3 and 2063.5 mg/g, respectively, demonstrating the excellent adsorption performance of the nanocomposite. Furthermore, this study examined the effects of contact time, initial MO and 2NP concentrations, pH, and temperature of the wastewater samples on the adsorptive removal of MO and 2NP by the GO/BENT/LTH nanocomposite. The pH, zeta potential, and FTIR investigations suggested the presence of more than one adsorption mechanism. Thermodynamic investigations elucidated the exothermic nature of the adsorption of MO and 2NP onto the GO/BENT/LTH nanocomposite, with MO adsorption being more sensitive to temperature change. Additionally, regeneration studies revealed a marginal loss in the MO and 2NP removal with the repetitive use of the GO/BENT/LTH nanocomposite, demonstrating its reusability. Overall, the findings of this study reveal the promise of the GO/BENT/LTH nanocomposite for effective water decontamination. • Novel GO/clay/MgFeAl-LTH nanocomposites is synthesized and characterized herein. • The nanocomposite outperformed its parental materials and their binary combinations. • The q max of MO and 2NP using this nanocomposite are >3000 and > 2000 mg/g, respectively. • Both pollutants adsorb spontaneously and exothermically on the nanocomposite. • The nanocomposite can be used multiple times with insignificant performance loss. [ABSTRACT FROM AUTHOR]

Background: In the present study, an electromembrane extraction (EME) followed by a simple high performance liquid chromatography with ultraviolet detection (HPLC-UV) was developed and validated for simultaneous determination of 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP) in pharmaceutical industrial wastewater sample. Main parameters of electromembrane extraction were evaluated and optimized. Methods: 1-octanol was immobilized in the pores of a polypropylene hollow fiber as supported liquid membrane. As a driving force, a 100 volt electrical voltage was applied to transfer the analytes from the sample solution (pH, 7.5) through the supported liquid membrane into an acceptor solution (pH, 12). Results: The best enrichment factors were obtained 36 and 72 for 2-NP and 4-NP, respectively after 15 minutes of extraction. The effect of carbon nanotube, as a solid nano-sorbent on EME efficiency, was also evaluated. The proposed method provided the linearity in the range of 10-1000 ng/mL for 2-NP (R2> 0.9997) and 4-NP (R2> 0.9999) with repeatability range (% RSD) between 2.6-10.3 % (n = 3). The limit of detection was 3 ng/mL and the limit of quantitation was 10 ng/mL. Conclusion: Finally, the method was applied for the determination of 2-NP and 4-NP in industrial wastewater samples with relative recoveries in the range between 67–76 %. EME improved the sensitivity of HPLC-UV for the determination of trace concentrations of these analytes.

The nitro and chloro derivatives of phenols are xenobiotics. Active carbon (AC) is often used for the removal of such substances from natural, drinking, and waste waters. To a large extent, the economic feasibility of using AC depends on the method of their regeneration. Upon treating AC with an alkaline solution, the adsorbed phenols are ionized because of their weak acidic properties. The formed phenolate ions are desorbed from the carbon surface because of their lower adsorption energy and AC is regenerated. The study of low-temperature desorption of phenol derivatives is relevant for the development of technology for the regeneration of AC and biologically active carbon (BAC) directly in adsorbers that are made of modern composite (fiberglass) materials that are not designed for operating at temperatures higher than 40–50°C. The low-temperature alkaline desorption of 2-nitrophenol (NP) from equilibrium exhausted AC (reagent : AC ratio 10 : 1) is studied under laboratory static conditions in the mode of single-batch processing. The optimal alkali concentration (0.1 M) providing the maximum degree of sorbent recovery is determined. It is found that the degree of desorption of NP (5.7–45.6%) depends on the equilibrium concentration of sorbent saturation. The lower the equilibrium concentration at which AC exhausts, the lower the efficiency of alkaline regeneration of AC. The efficiency of NP desorption for operating temperatures of 15–35°C is verified. An increase in the temperature of reagent in the studied range does not lead to a substantial increase in the degree of desorption, but reduces the time required to establish the equilibrium of desorption by a factor of 1.5. More than 85–90% of equilibrium 2-nitrophenol desorbed from AC is removed in the first 4 to 8 h of treatment. Compared to microbial treatment, alkaline desorption allows one to achieve higher levels of AC regeneration (by 10–20%) and shorter processing times (100 times faster), which indicates the promising future for inclusion of this operation into bioadsorption technologies. [ABSTRACT FROM AUTHOR]

In this work, a new porous Ag3PO4/(Cs, Rb)xWO3/g-C3N4/CoAl-LDH (CoAl-LDH - CoAl-layered double hydroxide) composite was synthesized through a facile method and utilized as a photocatalyst towards efficient photocatalytic degradation of phenol and its derivatives, 2-chlorophenol (2-CP) and 2-nitrophenol (2-NP). A series of characterization and experiments results showed the resultant composite had excellent structure and outstanding performance, 2-NP was degraded most completely, followed by 2-CP and finally phenol. Furthermore, the composite still remained favorable stability after five cycles and the possible photocatalytic degradation mechanism was proposed. This paper provided a new idea for the preparation of novel photocatalysts. [ABSTRACT FROM AUTHOR]

In the processes of water purification from organic matter, the biomass of biological activated carbon (BAC) can be used independently (separately from the carrier). In the present work, the enriched culture of microorganisms of biofilm biomass capable of effectively removing xenobiotics from more concentrated water solutions (45 mg/dm3) was obtained using the biofilm washed from the BAC laboratory filter, which has been used for several years for filtering 2-nitrophenol (NP) aqueous solution at a low concentration (8 ± 2 mg/dm3). The procedure of progressive adaptation, including moderate aeration, the stage of endogenous respiration and the elements of anaerobic system, was aimed at obtaining a specialized culture of microorganisms with enhanced survival rate, which would be able to increase the rate of NP destruction with each cycle of adaptation, to provide complete extraction of organic substrates and to prevent the accumulation of excessive concentrations of nitrates. The need of enriched biomass for the treatment of BAC regeneration wastewater arises occasionally. Hence, it is highly important to know the peculiarities of kinetics of biomass transition from the state of "maintenance" into the active state sufficient for effective destruction of the higher levels of xenobiotics, as well as the influence of additional substrates and biomass carriers on these processes. In the present work we have studied the effect of NP concentration, the NP/biomass concentration ratio and the form of biomass on the kinetics of xenobiotic extraction in a batch anaerobic process. Mathematical formulation of experimental data was performed in accordance with the Monod and Haldane/Andrews growth kinetics. During the progressive increase in the initial NP concentration (from 45–50 to 200 mg/dm3) based on the kinetic coefficients of the Haldane–Andrews equation, there was a change in the internal fermentative properties of microbial culture. The increase in specialization of the biomass is represented by a formal decrease in the values of the half-saturation constant Ks and an increase in the concentration inhibition constant Ki indicating the ability of the culture to adapt to assimilation of enhanced xenobiotic concentrations. The enriched native biomass adapted to 200 mg/dm3 of NP was effectively used for utilization of the waste from chemical regeneration of a laboratory BAC filter. Transition to the anoxic mode as the final stage of regeneration activated the groups of microorganisms capable of using nitrates as a terminal electron acceptor. [ABSTRACT FROM AUTHOR]

A novel green approach was adopted for carrying out the large scale synthesis of the Zinc oxide nanoflowers (ZNFs). The reducing power of maltose was utilized for reducing the precursor metal salt into NFs. The selection of the reaction constituents including water, and maltose as solvent, was done purely for achieving the goal of green synthesis. Capping agent of maltose was preferred over other biological stabilizers owing to its high solubility in water which removes all the problems found associated with the usage of the organic solvents. Similarly, usage of maltose as a reductant is not only beneficial from the economic point of view because of its cheapness but it is also highly valuable as it is an environmental friendly compound. Henceforth, an easy, simple, novel, facile and green method has been proposed for the synthesis of ZNFs. Engineered system exhibited excellent photocatalytic potential for the 2-nitrophenol (2-NP). [ABSTRACT FROM AUTHOR]

Amblyomma maculatum Koch (Ixodida: Ixodidae) has emerged as a significant vector of human and companion animal diseases in the U.S.A. When expanding in range, A. maculatum can be difficult to collect in the field and control on livestock. A novel method is needed to improve the field collection of A. maculatum, as well as to control their effects as ectoparasites of livestock and companion animals. The present study aimed to test the effects of known volatiles on the activation and selection choices of A. maculatum in a laboratory‐based Y‐tube assay and field‐based assays. Although the majority of adult A. maculatum were activated to move by five of the seven semiochemicals tested, only rumen fluid significantly attracted ticks to make a selection in the Y‐tube apparatus. Rumen fluid attracted the most A. maculatum in the laboratory, with 56% (84/150) making it to the rumen Y‐tube arm, although the results were not replicated in semi‐field experiments. These studies highlight the need for continued work to identify attractants for tick vectors that will assist field collections. These attractants could also be incorporated into management strategies that lead to prevention technologies to reduce tick burdens on cattle or in risk areas of humans. [ABSTRACT FROM AUTHOR]

In this research work, a simple method of silver nanoparticles' self-synthesis in chitosan (CH) biopolymer hydrogels without utilizing a reducing agent is shown. The synthesized material was used as a catalyst in different reduction reactions. For this purpose, different amounts of CH powder were dissolved in acidic aqueous solutions and then crosslinked it with the formaldehyde solution to make a CH biopolymer hydrogel. Among all the prepared samples, a CH hydrogel prepared from a dense solution was found to be suitable for this study because of good mechanical stability. For the self-synthesis of silver nanoparticles inside hydrogel, it was immersed in an aqueous solution of AgNO3 (10 mM) for 3 days at room temperature. The color of the chitosan hydrogel changed to brown from transparent which indicated the successful formation of silver nanoparticles on CH hydrogel (Ag-CH). No reducing agent for conversion of the Ag1+ ions to nanoparticles in this whole synthesis method. Instrumental techniques such as FESEM, XRD and EDX analysis confirmed the successful preparation of Ag-CH. The Ag-CH was checked as a catalyst in the 2-nitrophenol (2-NP) and acridine orange (ArO) reduction reactions. Both reactions were carried out at high rate constants (2-NP = 0.260 min−1, ArO = 0.253 min−1) by using the Ag-CH hydrogel catalyst. In addition, we discussed the mechanism of action of the reducing agent, the effect of kapp on the two reduction reactions of Ag-CH and the recyclability. [ABSTRACT FROM AUTHOR]

The optical and electrochemical characterization of the synthesized Ag+ modified WO 3 photocatalysts was performed and its photocatalytic activity was estimated in the visible region (420–800 nm) of sunlight for the degradation of 2-chloro and 2-nitrophenol. The catalysts with the varying loading of Ag+ ranging from 0.5% to 10%, exhibited significantly higher activity as compared to pure WO 3. Attempts were made to correlate the enhanced activity of Ag+ loaded catalysts with the optical and electrochemical properties. At lower loading (up to 1% Ag+), the enhanced degradation was attributed to the excited electron trap and transfer ability of surface mounted Ag+ species, while the synergic effect between the WO 3 support and surface Ag 2 O resulted the same at higher loadings. The electrochemical properties of the synthesized powders, in comparison with pure WO 3 , also supported the same findings. The identification of the intermediates and the estimation of the released anions evidenced the contribution of both hydroxyl radicals (HO) and superoxide anion (O 2 −) radicals in the degradation process. The identification of aliphatic oxygenates as majority intermediates and release of respective ions verified the replacement of Cl− and NO 2 groups, insertion of oxygen and aromatic ring cleavage. [ABSTRACT FROM AUTHOR]

• Phenol and 2-nitrophenol on a biopolymer derived biochar adsorbent was analyzed. • Theoretical analysis of phenol and 2-nitrophenol adsorption mechanisms was performed. • The role of adsorbate structure on tested adsorbents was theoretically explained. In this paper, the adsorption of phenol and 2-nitrophenol on a biopolymer-based biochar in single and binary systems was investigated at 298–328 K and pH 5. Experimental results indicated that the adsorption capacities of phenol were significantly reduced from single to binary systems compared to those obtained for 2-nitrophenol. This experimental evidence suggested an antagonistic effect between both adsorbates generating an inhibitive adsorption. In terms of modeling analysis, the single and binary adsorption isotherms were well reproduced by monolayer and competitive monolayer statistical physics models, respectively. These two models showed that phenol and 2-nitrophenol molecules have been mainly docked with an inclined and horizontal positions in single and binary systems, respectively. A detailed analysis of the number of captured phenol (n 1) and 2-nitrophenol (n 2) molecules per site in the binary systems demonstrated that its corresponding evolution varied with a completely inverse way thus corroborating the inhibition effect between phenol and 2-nitrophenol molecules. The monolayer and competitive monolayer models were used to estimate two adsorption energies to characterize the single and binary adsorption mechanisms. The analysis of the energetic parameters suggested that the adsorption process was a physisorption. The interpretation of all monolayer and competitive monolayer model parameters provided new insights that contributed to understand the single and binary adsorption mechanisms of phenol and 2-nitrophenol molecules on tested adsorbent. [ABSTRACT FROM AUTHOR]

Nickel ferrite nanoparticles prepared by a microwave-assisted autocombustion method with different fuels and microwave powers were used as bare adsorbents for 2-nitrophenol removal from aqueous solutions. Characterization of the as-prepared samples revealed a fundamental variety with respect to their size and surface area. Meanwhile, the crystal phase, functional groups, surface polarity, and magnetic properties remained almost the same. After electing the most efficient adsorbent based on batch experiments, pH influence was established and optimized. Afterward, equilibrium studies were conducted. The kinetic models and adsorption isotherms further facilitated a better understanding of the adsorption mechanism that comprised mainly the multilayered condensation of 2-nitrophenol molecules through the hydrogen bonding. [ABSTRACT FROM AUTHOR]

In this work, the combination of H2O2 and an active visible‐light‐driven photocatalyst (Ag‐S/PEG/TiO2) was utilized under natural solar radiation for the degradation of 2‐nitrophenol (2‐NP), and interaction effects between the photocatalyst and hydrogen peroxide were analyzed. For this purpose, experiments were designed using the response surface methodology based on the central composite design. The resulting data was utilized to obtain a model for the prediction of response (the degradation efficiency) as a function of two independent factors (H2O2 concentration and the photocatalyst loading). The statistical analysis indicated that optimum values of each of the two independent factors decreased by increasing the other one and vice versa. Moreover, it was found that adding the optimal amount of H2O2 to the solution, which contained just the photocatalyst, can enhance the degradation significantly (up to 45 %). However, using higher concentrations of H2O2 may decrease the efficiency. The global optimum condition was found to be 545 ppm and 316 mM for Ag‐S/PEG/TiO2 loading and H2O2 concentration, respectively. In this condition, the degradation efficiency of 2‐NP reached 92.4 % after only 45 min of solar light irradiation. [ABSTRACT FROM AUTHOR]

The efficiency and peculiarities of 2-nitropenol (NP) desorption from activated carbons under the action of biotic and abiotic factors have been studied. The biotic NP desorption during one month reached 25–30% of the initial saturation of sorbent. The rational duration of bioregeneration was found to be equal to 14 days. The rate of biotic desorption is shown to be limited by the rate of internal diffusion. The intensity of self-bioregeneration of biological activated carbon is by an order of magnitude less that the NP destruction rate in the solution volume and to a greater degree corresponds to the intensity of abiotic desorption. [ABSTRACT FROM AUTHOR]

Abstract Fluorescent silicon nanoparticles (SiNPs) displayed different emission wavelengths have been synthesized, but it has not been reported that the preparation of wavelength controllable SiNPs by adjusting the nitrogen content of reducing agents. In this paper, the wavelength-controlled fluorescent SiNPs were prepared by selecting the dopamine (DA) with nitrogen content between catechol and 2-aminophenol as the reducing agent and N-[3-(trimethoxysilyl) propyl]-ethylenediamine (DAMO) as the silicon source via one-step hydrothermal method. The emission wavelength of the prepared SiNPs was in direct proportion to the nitrogen content in the reducing agent. To the best of our knowledge, this is the first time for exploring the nitrogen content in reducing agents could affect the optical properties of SiNPs so far. In addition, the obtained SiNPs could be applied to determinate 2-nitrophenol (2-NP). Based on the combination action of inner filter effect (IFE) and static quenching effect (SQE) mechanism, a wide linear range was obtained from 0.1 to 500 μM, and the limit of detection was 0.029 μM for 2-NP, which was comparable to or even lower than some previous reports. This SiNPs probe was also successfully employed for sensing of 2-NP in industrial effluent with satisfactory results (98.6%–103.4%). Graphical abstract (A) A schematic of the preparation of SiNPs; (B) The schematic of the SiNPs for 2-NP sensing. fx1 Highlights • Wavelength controllable fluorescent SiNPs were prepared via a one-step hydrothermal method. • It was verified that the emission wavelength of SiNPs is related to the nitrogen content in the reducing agent. • The method realized the detection of 2-nitrophenol in 30 s and presented good sensitivity and selectivity. • The synergistic action of inner filter effect and static quenching effect. [ABSTRACT FROM AUTHOR]

Abstract Herein, the fluorescent carbon dots (CDs) has been synthesized by hydrothermal method by using ethylene diamine tetraacetic acid (EDTA) as a raw materials. The prepared CDs exhibited bright blue fluorscence excited by 340 nm with the quantum yield as high as 52%. The CDs possess special fluorescence responses to 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP), and the slump of fluorescence was demonstrated by CDs solution in the case of 2-nitrophenol and 4-nitrophenol existence. The detection limit of 2-NP and 4-NP was calculated at 77 nM and 60 nM, respectively. Meanwhile, the color response to 2-NP and 4-NP can be observed from achromatic solution to yellow by naked eye. All in all, the obtained CDs can be applied as fluorescence and colorimetric probe in environmental protection. Graphic abstract Synthetic route of CDs and process of the probe for detecting 2-NP and 4-NP by fluorescence and colorimetric process. fx1 [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Bio-surfactant assisted in situ synthesis of nanostructured Fe 3 O 4 on RGO sheets. • The natural bio-molecules modify the physiochemical features of nanostructured Fe 3 O 4. • Surface modified nanostructured Fe 3 O 4 on rGO exhibits superior photocatalytic activity. • Fe 3 O 4 @3 wt% rGO shows high performance for 2-Nitrophenol reduction and TCH degradation. Abstract An eco-friendly and bio-surfactant assisted room temperature synthesis has been proposed for preparation of Magnetic retrievable Fe 3 O 4 @rGO nanocomposite in Averrhoa carambola leaf extract towards 2-nitrophenol reduction and TCH degradation under visible light illumination. The role of bio-molecules that are present in leaf extract is quite crucial in the process of tuning the morphology and opto-electronic features of Fe 3 O 4 nanoparticles. Additionally, the insitu conversion of GO to rGO and preparation of Fe 3 O 4 from Fe+2 and Fe+3 metal precursors leads to formation Fe 3 O 4 @rGO nanocomposite. rGO sheets play the key role in successful transfer and separation of photoexcited charge carrier resulting in better catalytic activity compared to neat Fe 3 O 4. Among the designed nanocomposites 3 wt% loaded rGO i.e. FG-3 shows the best result with 95.85% 20 ppm 2 Nitrophenol reductions and 94.09% 10 ppm TCH degradation under visible light irradiation for 30 and 60 mins respectively. The observed high photocatalytic performance of FG-3 is attributed to synergetic chemistry operating between rGO and Fe 3 O 4 components that causes effective separation and channelization of excitons to active sites and also due to increase in surface area of composite material. The above stated separation efficiency and surface area expansion is well supported by PL/Impedance measurements and BET analysis respectively. Further the phase purity, uniform distribution of nanoparticles and reduction of GO to rGO is well characterised through XRD, FESEM/TEM and Raman/FTIR analysis respectively. [ABSTRACT FROM AUTHOR]

An efficient green method of gold nanoparticles (AuNPs) biosynthesis was achieved by cell‐free extracts of fungus Trichoderma sp. WL‐Go. Based on UV–Vis spectra, AuNPs biosynthesised by cell‐free extracts with 90 mg/l protein exhibited a characteristic absorption band at 556 nm and was stable for 7 days. Transmission electron microscopy images revealed that the as‐synthesised AuNPs were spherical and pseudo‐spherical, and the average size was calculated to be 9.8 nm with a size range of 1–24 nm. The AuNPs illustrated their good catalytic activities for reduction of nitro‐aromatics (2‐nitrophenol, 3‐nitrophenol, 4‐nitrophenol, 2‐nitroaniline, 3‐nitroaniline) with catalytic rate constants of 7.4 × 10−3 s−1, 10.3 × 10−3 s−1, 4.9 × 10−3 s−1, 5.8 × 10−3 s−1, 15.0 × 10−3 s−1, respectively. Meanwhile, the AuNPs also showed excellent catalytic performance in decolourisation of azo dyes with decolourisation efficiency from 82.2 to 97.5%. This study provided a green gentle method for AuNPs synthesis as well as exhibiting efficient catalytic capability for degradation of aromatic pollutants. [ABSTRACT FROM AUTHOR]

Removal of 2-nitrophenol (2NP) from aqueous solution was performed using Sono-Fenton process. The Box–Behnken design (BBD) of experiments was used to investigate the influence of operational factors such as pH, initial concentration of hydrogen peroxide and ferrous ions on the removal of 2NP. The ANOVA (analysis of variance) showed a satisfactory prediction second-order regression model and a high determination coefficient value. The optimum conditions predicted by the model were as follows: the [Fe2+] = 10 mg/L, pH 3, and [H2O2] = 475 mg/L. The results showed that at the predicted optimum conditions and after 60 min of reaction, the degradation of 70 mg/L of 2NP and its corresponding Chemical oxygen demand (COD) was 97.8 and 76.5%, respectively. The kinetic study for mineralization of 2NP was investigated and the rate constants (K = 25.4 × 10–3 min–1) and half-life time of mineralization reaction ( = 27.28 min) were achieved. [ABSTRACT FROM AUTHOR]

Many types of oxidative pollutants are dangerous chemicals and may pose a health risk, but an inexpensive and effective method for mitigating those risks would offer significant advantages. The objective of this study was, therefore, to investigate the potential for Fe-pillared montmorillonite to fill that gap. Surface mediated reduction reactions by ferrous species often play an important role in governing the transport, transformation, and fate of hazardous oxidative contaminants. Compared to the untreated montmorillonite (Mnt), the synthetic polyhydroxyl-Fe pillared montmorillonite (Fe-Mnt) was found to be somewhat similar to goethite in promoting the ability of specifically adsorbed Fe(II) to reductively transform 2-nitrophenol (2-NP). The 2-NP was efficiently removed within 30 min from solutions at the optimum neutral pH in a mixed reduction system of Fe(II)/Fe-Mnt under an anoxic atmosphere. This demonstrated that the specifically adsorbed Fe(II) of Fe-Mnt can enhance 2-NP reduction. The highly enhanced 2-NP reduction by Fe(II) through Fe-Mnt surface catalysis can, therefore, be ascribed to clearly increased amounts of an adsorbed Fe(II) species surface complex, which gave rise to enhanced Fe(II) reductive activity that enabled the rapid reduction of 2-NP. The reduction processes produced a faster transformation of 2-NP in a Fe-Mnt suspension than in a Mnt suspension. The transformation kinetics were described using pseudo-first-order rate equations. Moreover, in addition to the effects of mineral surface properties, the interactions were affected by the aqueous chemistry, and the removal rates of 2-NP were increased at pHs of 6.0–7.3. In the present study, the structure and surface reactivity of Fe-Mnt was characterized in depth. The polyhydroxyl-Fe added to Mnt and the pH were determined to be the two key controlling factors to mediate the reductive transformation of 2-NP in the presence of Fe-Mnt in comparison to goethite and Mnt. Finally, the catalysis mechanism responsible for the enhanced 2-NP reduction by Fe(II) was elucidated using cyclic voltammetry. [ABSTRACT FROM AUTHOR]

The non-magnetic and magnetic polymorphs of iron oxide (Fe 2 O 3 ) namely: α-Fe 2 O 3 (hematite) and γ-Fe 2 O 3 (maghemite) respectively, were synthesized by a facile surfactant aided hydrogel route. The synthesized polymorphs were characterized by diffuse reflectance, photoluminescence and raman spectroscopy for optical properties whereas the morphological, structural, chemical and electronic state evaluation were performed by FESEM, HRTEM, XRD, and XPS. The charge transport and the stability of the materials were examined electrochemically. The photocatalytic activity of the synthesized polymorphs was evaluated for the degradation of 2-chlorophenol and 2-nitrophenol in the exposure of the visible region and complete spectrum natural sunlight. Both the polymorphs exhibited a significantly high activity for the degradation of the phenolic substrate in the exposure of the complete spectrum of sunlight, however, the activity in the visible region of the sunlight was relatively lower. A substantial increase in the activity in the visible region was noticed when the polymorphs were exposed to complete spectrum sunlight prior to the photocatalytic experiments. The comparison of the exposed and unexposed samples revealed the induction of defects that served as traps for the excited electrons and increased activity of the polymorphs. [ABSTRACT FROM AUTHOR]

Eragrostis plana Nees leaves, abundant lignocellulosic biomass, was used as carbon source for preparation of activated carbon, by using microwave-assisted pyrolysis and chemical activation. The novel activated carbon (MWEPN) was characterised by FTIR, CHN elemental analysis, Boehm’s titration method, TGA, SEM, N2 adsorption/desorption curves and pH of the point of zero charge (pHpzc). Afterwards, the adsorbent was successfully employed for adsorption of the two emerging contaminants (caffeine and 2-nitrophenol). The results indicated that MWEPN had a predominantly mesoporous structure with a high surface area of 1250 m2 g−1. FTIR analysis indicated the presence of carbonyl, hydroxyl and carboxylic groups on the surface of MWEPN. The Boehm analysis showed the existence of the high amount of acid moieties on the surface of activated carbon. Adsorption kinetic indicated that the system followed the Avrami fractional order at the optimal pH of 7. The equilibrium time was attained at 30 min. The Liu isotherm model better described the isothermal data. Based on the Liu isotherm, the maximum sorption capacities (Qmax) of caffeine and 2-nitrophenol adsorbed onto activated carbon at 25 °C were 235.5 and 255.8 mg g−1, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Algerian Journal of Environmental Science & Technology is the property of Algerian Journal of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: An efficient protocol for the synthesis of benzoxazoles from o‐nitrophenols and benzyl alcohols using CuNiFe as a magnetic nano‐catalyst via hydrogenation transfer has been described. The CuNiFe magnetic nano‐catalyst was prepared by an operationally simple method, without the use of any toxic reagents. The prepared catalyst was characterized by XRD, FEG‐SEM, EDAX, TEM, and FT‐IR techniques. No additional additives such as oxidants and reductants were required for this reaction. CuNiFe magnetic nano‐catalyst showed good air stability and could be recycled up to six times without any significant loss in its catalytic activity. [ABSTRACT FROM AUTHOR]

Metal oxychlorides of Fe, Cu, Bi and Zn were prepared and tested in heterogeneous Fenton degradation of 20 ppm of 2-Nitrophenol (2-NP) in the presence of ultrasonic (US, 20 kHz), ultraviolet (UV, 6 W, λ = 254 nm), and US/UV coupled irradiations. The different experimental conditions including the catalysts dosages, hydrogen peroxide concentration, pH value, temperature, pollutant concentration and irradiation time were optimized and the reusability of the tested metal oxychlorides was investigated as well. The capability of 2-NP degradation follows the order US/UV > UV > US. The rate constant of degradation using sonophotocatalytic system was even higher than the sum of rates of individual systems due to its synergistic performance. Times of 30, 40, 50 and 50 min were respectively needed for Fe, Cu, Bi and Zn oxychlorides to accomplish complete degradation under the experimental conditions of 0.1 gL −1 solid, 5 mM H 2 O 2 , pH 7 and 25 °C. The rate constant of degradation followed the same order of mentioned metals with values of 0.15, 0.0871, 0.0964, 0.0806, and 0.0738 min −1 for Fe, Cu, Bi and Zn oxychlorides, respectively. The mechanism proposed considers a major role of produced hydroxyl radicals while the difference in band gap energy was emphasized in case of Bi and Zn oxychlorides. [ABSTRACT FROM AUTHOR]

Investigated are changes of the porous structure of biological activated carbon in filtration and after chemical regeneration. It is shown that 71-84 vol % of recovered pores were blocked by the products of microbe vital activity. Alkaline treatment of the bed of biological activated carbon (during several days) makes it possible to prolong efficient nitrophenols removal from water by 10-11 months. [ABSTRACT FROM AUTHOR]

Activated carbons (ACs) prepared from tucumã seed (Astrocaryum aculeatum) were used for 2-nitrophenol removal from aqueous solutions. The ACs were characterized by elemental analysis, FTIR, N2 adsorption/desorption isotherms, TGA, hydrophobicity/hydrophilicity balance, and total of acidic and basic groups. The ACs showed to have hydrophilic surfaces and they presented high specific surface areas (up to 1318 m2 g−1). In batch optimization studies, maximum removal was obtained at pH 7, contact time of 30 min, adsorbent dosage 1.5 gL−1 and temperature of 50°C. The general-order kinetic model and Liu isotherm model best fit the kinetic and equilibrium adsorption data with a maximum adsorption capacity of 1382 mg g−1 at 50°C. Effect of temperature and thermodynamic studies revealed that the adsorption processes of 2-nitrophenol onto ACs are dependent on temperature and are exothermic and spontaneous, respectively. About the applicability of the ACs for treating simulated effluents, the tucumã seed-activated carbon showed an excellent outcome in the treatment of simulated effluents, evidencing its high efficiency for phenolic compound adsorption. Tucumã seed-ACs showed to be cost effective and highly efficient adsorbents for efficient removal of 2-nitrophenol from aqueous solutions. [ABSTRACT FROM AUTHOR]

The induced degradation and detoxification of 2-nitrophenol (2-NP) in aqueous media by gamma irradiation were carefully evaluated in this study. Gamma radiation at absorbed doses as low as 20 kGy was able to degrade 2-NP to reach a removal of at least 85% across the investigated range of concentration (50-150 ppm). 2-NP breaks down to aromatic-based compounds with increasing number of byproducts upon increasing the radiation treatment from the absorbed dose of 50% decomposition (D50) to the absorbed dose of 90% decomposition (D90), after which no byproducts could be detected, indicating the formation of undetectable aliphatic hydrocarbons, insoluble, or volatile byproducts. Toxicology studies showed that the degradation of 2-NP under absorbed doses up to D90 resulted in a more toxic byproduct than the parent compound, and a remarkable reduction in the toxicity was observed with the irradiated samples with absorbed doses above D90. Varying the pH of the media to acidic or basic conditions did not significantly alter the degradation behavior of 2-NP. However, a notable improvement of the detoxification was associated with the samples of acidic pH. Adding 0.5% of H2O2 to 2-NP solutions had a positive effect by reducing D90 by a factor of nine and diminishing the toxicity by twofolds [ABSTRACT FROM AUTHOR]

A new material by polymer insertion via graphene oxide into cerium tungstate was prepared by very simple oxidation-reduction method. Aniline polymerization was done on the surface of graphene oxide (GO) which was reduced to graphene (G) simultaneously mixed with separately prepared inorganic matrices of cerium tungstate (Ce 2 (WO 4 ) 3 (CWO)). PANI@G/CWO was characterized by various spectroscopic methods as SEM, FTIR, TGA, XRD and XPS to confirm its possibilities. Selective 2-nitrophenol sensor was fabricated on flat glassy carbon electrode (GCE) and PANI@G/CWO nanocomposites in the form of thin layer. It was found excellent sensitivity as well as long life spam with broad dynamic concentration range (LDR) that showed efficient electrochemical performance towards 2-nitrophenol on fabricated chemical sensor by PANI@G/CWO. The linear calibration curve (r 2 = 0.9914) with wide range of 2-nitrophenol concentration (1.0 nM–1.0 mM) was found having the detection limit of 0.87 nM while the sensitivity of the sensor was around 1.229 μ A μM −1 cm −2 . It was introduced a new route for the development of a versatile phenolic sensor based on PANI@G/CWO nanocomposites by I–V method that is proved more selective and sensitive for environmental toxic materials. [ABSTRACT FROM AUTHOR]

We developed a selective solvothermal synthesis of palladium nanoparticles on nanodiamond (ND)-graphene oxide (GO) hybrid material in solution. After the GO and ND materials have been added in PdCl solution, the spontaneous redox reaction between the ND-GO and PdCl led to the creation of nanohybrid Pd@ND@GO material. The resulting Pd@ND@GO material was characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectrometry, scanning electronic microscopy (SEM), and atomic absorption spectrometry methods. The Pd@ND@GO material has been used for the first time as a catalyst for the reduction for 2-nitrophenol and the degradation of methylene blue in the presence of NaBH. GO plays the role of 2D support material for Pd nanoparticles, while NDs act as a nanospacer for partly preventing the re-stacking of the GO. The Pd@ND@GO material can lead to high catalytic activity for the reduction reaction of 2-nitrophenol and degradation of methylene blue with 100% conversion within ~15 s for these two reactions even when the content of Pd in it is as low as 4.6 wt%. [ABSTRACT FROM AUTHOR]