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Paper bleaching effluent was treated by catalytic wet oxidation method and the effect of the type of the catalyst on the efficiency was investigated. Cerium oxide, cobalt oxide and copper oxide based (CuOx-CoOx-CeO2) composite catalysts which were varying with regard to CuOx, CoOx and CeO2 compositions were prepared by co-precipitation method. The efficiency of the process was determined by measuring the chemical oxygen demand (COD), total organic carbon (TOC), adsorbable organic halides (AOX) and Cl− removal yields. When the COD, TOC and AOX removal yields were considered, better results were achieved with copper and ceria based catalysts than the cobalt based catalysts. At the optimum reaction conditions (T—473 K, t—120 min, P—130–250 psig), the maximum removal yields obtained by the 50% CuOx–50% CeO2 catalyst. When the wastewater of the I stage of paper bleaching process was treated, removal yields of TOC, COD and AOX were detected as 89; 94 and 95%, respectively Whereas, removal yields of 53% COD, 84% TOC, 90% AOX and 76% Cl− were achieved for the III stage wastewater. It was shown that removal of the toxicity of wastewater samples that were collected from the paper bleaching process by the proposed treatment methods.

Paper industries are water-intensive industries that produce large amount of wastewater containing dyes, toxicity and high nutrient content. These industries require sustainable technology for their waste disposal and MEC could be one of them. However, effective MEC operation at neutral pH and ambient temperature requires economical and efficient cathodes that are capable to treat indusial wastewater along with recovery of energy/biohydrogen. Co-deposits of Nickel, Nickel–Cobalt and Nickel–Cobalt–Phosphorous on the surface of SS and Cu base metals distinctly were used as cathodes in MEC for the concurrent treatment of real paper industry wastewater and biohydrogen production. MECs were utilized in batch mode at neutral pH, applied voltage of 0.6 V and 30 ± 2 °C temperature with paper industry wastewater and activated sludge as microbial sources. The fabricated Nickel–Cobalt–Phosphorous gives the higher hydrogen production rate of 0.16 ± 0.002 m3(H2) m−3d−1 and 0.14 ± 0.002 m3(H2) m −3d −1 respectively, with ~33–42 % treatment efficiency for a 500 ml wastewater in 7-day batch cycle in both the cases; while it is lowest in the case of the control cathodes (SS1 (0.07 ± 0.002 m3(H2) m−3d−1) & Cu1 (0.06 ± 0.004 m3(H2) m−3d−1)). It was also found that fabricated cathodes have the capability to treat industrial wastewater at ambient conditions efficiently with higher energy recovery. Prepared cathodes show enhanced hydrogen production and treatment efficiency as well as are competitive to some reported literature.

In this work, a new chemiluminescence (CL) system of Co-Fe prussian blue analogs nanocubes (Co-Fe PBA NCs) that can catalyze luminol to produce strong CL in the absence of H2O2 was established. Co-Fe PBA NCs have the property of oxidase-like activity, and it can catalyze the generation of active oxygen radicals in a dissolved oxygen system. Since caffeic acid (CA) can remove reactive oxygen species in the system, a sensitive detection method for CA on a paper-based chip was developed. Under the optimal conditions, this method showed a good linear response to CA in the range of 10 - 800 ng mL-1 with a limit of 3 ng mL-1. The proposed method had been used for the determination of CA in tea samples. The results may open a new avenue for the catalytic property on luminol CL system without extra oxidants.

Ceramic paper discs were made by employing a dual papermaking technique and by partially substituting cellulosic fibres by SiO2-Al2O3ceramic ones. Ulexite (NaCaB5O6(OH)6�5(H2O)), extracted from the natural mineral, was added as a binder to give ceramic paper the necessary strength for its manipulation and catalytic use. Either La,Co or Ba,Co was incorporated in order to give ceramic paper the capability of trapping NOx and oxidizing soot particles. Structured catalysts were characterised by SEM, FTIR and XRD, and the mechanical properties were also determined. Lanthanum was deposited on ceramic fibres as La2O2CO3aggregates and barium as BaCO3filaments, being cobalt deposited as Co3O4flakes. Mechanical properties indicated that the ceramic paper obtained from natural ulexite proved to be stronger, though less flexible than those prepared using colloidal suspensions as a binder. Diesel soot oxidation activity was determined by TPO either adding or not 0.1% NO into the feeding stream. The thus prepared systems resulted in being active towards soot oxidation, being the value of maximum combustion rate 420 �C, which is within the temperature range of diesel exhaust gases. Fil: Leonardi, Sabrina Antonela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Zanuttini, Miguel Angel Mario. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Miro, Eduardo Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Milt, Viviana Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina

Sulfur quantum dots are promising alternatives for traditional heavy metal-containing quantum dots due to their benign chemical properties and low cytotoxicity. Herein, cysteine-decorated sulfur dots were prepared from facile modification of pristine sulfur dots and can be acted as a chemosensor for the fluorometric and colorimetric dual-channel detection of cobalt (Co2+) with high sensitivity and selectivity. Visual colors of the as-prepared chemosensor in the presence of Co2+ changed from blue to colorless under UV light and also can transform from colorless to yellow under sunlight based on the photoinduced electron transfer effect. The detection limit of cysteine-decorated sulfur dots toward Co2+ was determined as low as 0.16 μM with a wide detection range, which is lower than the permitted guideline level by Department of Environmental Protection for drinking water (1.7 μM). Furthermore, portable paper sensor-based cysteine-decorated sulfur dots were fabricated for Co2+ detection and showed superior detection ability. Aided by a common smartphone as detector, the rapid, on-site and accurate quantification of Co2+ in real water samples can be accomplished. Our research has provided a novel chemosensor based on sulfur dots for dual-channel detection of Co2+, which would expand applications of sulfur dots in environmental monitoring, diseases diagnosis, cell imaging, light-emitting diodes, etc. Cysteine-decorated sulfur dots were acted as a chemosensor for fluorometric and colorimetric dual channel detection of Co2+ based on the photoinduced electron transfer effect.

Graphical abstract, Highlights • New cobalt metal-organic framework modified carbon cloth/paper (Co-MOF/CC/Paper) hybrid button-sensor. • Portable, robust, and user-friendly electrochemical analytical chip for nonenzymatic glucose sensing. • Effectively increasing the specific area and catalytic sites based on the Co-MOF/CC interface. • Low-cost and simple on-chip application with desired selectivity, stability, and durability in complex biomatrixes., In the growing pandemic, family healthcare is widely concerned with the increase of medical self-diagnosis away from the hospital. A cobalt metal-organic framework modified carbon cloth/paper (Co-MOF/CC/Paper) hybrid button-sensor was developed as a portable, robust, and user-friendly electrochemical analytical chip for nonenzymatic quantitative detection of glucose. Highly integrated electrochemical analytical chip was successfully fabricated with a flexible Co-MOF/CC sensing interface, effectively increasing the specific area and catalytic sites than the traditional plane electrode. Based on the button-sensor, rapid quantitative detection of glucose was achieved in multiple complex bio-matrixes, such as serum, urine, and saliva, with desired selectivity, stability, and durability. With the advantages of low cost, high environment tolerance, ease of production, our nanozyme-based electrochemical analytical chip achieved reliable nonenzymatic electrocatalysis, has great potential for the application of rapid on-site analysis in personalized diagnostic and disease prevention.

Electrode materials as an important component for the supercapacitors (SC) mainly undertake energy storage. Hence, the research hotspots in the SC fields are focused on the active materials of the electrode. In this study, we have provided a facile synthesis method to prepare reduced graphene oxide (RGO) and cobalt carbonate hydroxide (Co(CO3)0.5(OH)0.11·H2O) nanorod composites. The RGO films were obtained by vacuum filtration of GO papers and hydrothermal method. And during this hydrothermal, Co(CO3)0.5(OH)0.11·H2O nanorods also grow on the surface of RGO films. The as-fabricated RGO/Co(CO3)0.5(OH)0.11·H2O composites are characterized by SEM, EDS, XRD measurement. According to the electrochemical research results, the RGO/Co(CO3)0.5(OH)0.11·H2O electrodes own an ultrahigh volumetric capacitance of 1627 F cm−3 at a current density of 0.5 A g−1. Besides, the energy density of the symmetrical supercapacitor (SSc) assembled with the RGO/Co(CO3)0.5(OH)0.11·H2O electrode material is 9.22 mW h cm−3, and the capacity can be maintained 100.0% after 10,000 cycles when the composite material at the current density of 1 A g−1, these promote an efficient electrode material for electrochemical supercapacitor applications.

The successful attempt to solve the crystal structure of Co(CO3)0.5(OH)·0.11H2O (denotedCCH), based on synchrotron powder diffraction data, leads to a drastic revision of the chemical formula to Co6(CO3)2(OH)8·H2O [hexacobalt(II) bis(carbonate) octahydroxide monohydrate] and to a hexagonal cell instead of the orthorhombic cell suggested previously [Portaet al.(1992).J. Chem. Soc. Faraday Trans.88, 311–319]. This results in a new structure-type related to malachite involving infinite chains of [CoO6] octahedra sharing edges along a shortcaxis, delimiting tunnels having a three-branched star section. All reports discussing cobalt hydroxycarbonates (CCH) without any structural knowledge and especially its topotactic decomposition into Co3O4have, as a result, to be reconsidered.

Filter paper has been sequentially enchased with titania (TiO2) nanoparticles and coated by a cobalt-porphyrin/dansyl piperazine complex. A series of “turn on” fluorescence sensors are demonstrated to show high sensitivity and fast response for ammonia gas.

The oxygen reduction reaction (ORR) is a vitally important process in fuel cells. The development of high-performance and low-cost ORR electrocatalysts with outstanding stability is essential for the commercialization of the electrochemical energy technology. Herein, we report a facile synthesis of cobalt (Co) and nitrogen (N) co-doped carbon nanotube@porous carbon (Co/N/CNT@PC-800) electrocatalyst through a one-step pyrolysis of waste paper, dicyandiamide, and cobalt(II) acetylacetonate. The surface of the hierarchical porous carbon supported a large number of carbon nanotubes (CNTs), which were derived from dicyandiamide through the catalysis of Co. The addition of Co resulted in the formation of a hierarchical micro/mesoporous structure, which was beneficial for the exposure of active sites and rapid transportation of ORR-relevant species (O2, H+, OH−, and H2O). The doped N and Co formed more active sites to enhance the ORR activity of the electrocatalyst. The Co/N/CNT@PC-800 material exhibited optimal ORR performance with an onset potential of 0.005 V vs. Ag/AgCl and a half-wave potential of –0.173 V vs. Ag/AgCl. Meanwhile, the electrocatalyst showed an excellent methanol tolerance and a long-term operational durability than that of Pt/C, as well as a quasi-four-electron reaction pathway. The low-cost and simple synthesis approach makes the Co/N/CNT@PC-800 a prospective electrocatalyst for the ORR. Furthermore, this work provides an alternative approach for exploring the use of biomass-derived electrocatalysts for renewable energy applications.

As one of the most toxic contaminants, arsenic (As) is well-known for diverse types of adversary effects on the life of living beings. Unfortunately, as the conventional methods of its detection generally suffer from several demerits (e.g., long duration, high cost, and complexity), the engineering of advanced materials could be a solution for the development of next generation sensors. In an effort to validate such proposition, we developed a molybdenum based metal–organic framework (Mo-MOF) by modifying a common form of [(Mo2O6)(4,4′–bpy)]n) as a new sensing platform for As. We have successfully developed and characterized a mixed metal (Co/Mo) MOF for the specific, sensitive, and expeditious detection of As(V) metal ions. The color changing capacity (from purple to blue) of Co/Mo-MOF is found to maintain a good linear relationship with changes in the concentration of As(V) from 0.05 ppb to 1000 ppm. This Mo-based MOF sensor, when bound with spectroscoptic and paper-based methods, offered exceptionally low limits of detection (LOD) for As(V) ions such as 0.02 and 0.04 ppb, respectively.

Fabricating low-cost and high-efficiency oil-water separation superwetting materials for the demand of oil spilling treatment remains a great challenge. Herein, a superwetting aluminosilicate fiber paper decorated by flower-like nickel-cobalt carbonate hydroxide (NiCo-CH) nanostructures was prepared via the hydrothermal method and chemical modification with stearic acid (SA) or 1H, 1H, 2H, 2H-Perfluoroalkyltriethoxysilane (FAS-17). The superhydrophilic multi-layers nanoflowers combing with nanoflakes were uniformly distributed on the surface of aluminosilicate fiber. The superhydrophilic aluminosilicate fiber was then modified by the SA to obtain the superhydrophobic aluminosilicate fiber (SA-NiCo-CH@Al2SiO5 FP). The SA-NiCo-CH@Al2SiO5 FP revealed high separation efficiency (> 95.4%) for both light oils and heavy oils, and high oil flux (417 L m−2 h−1–71,656 L m−2 h−1). Furthermore, the SA-NiCo-CH@Al2SiO5 FP can also remain superhydrophobicity under various harsh conditions, such as dust, sand impact, acid or alkali, and low-temperature environments. This study revealed an inexpensive and simple-fabricated multifunctional superwetting material, which provides promising avenue for future applications in oil-water separation.

Cobalt-based nanomaterials have received considerable attention in electric energy-storage devices due to their outstanding electrochemical characteristics. However, multiple time- and energy-consuming steps and complex reduction processes for producing cobalt and cobalt oxide nanostructures are disrupting their substantive commercialization. Here, we propose a facile, ultra-fast, and versatile method for the fabrication of cobalt and cobalt oxide nanostructures using an intense pulsed white light (IPWL) photothermal reduction technique. The mechanism of the IPWL photothermal reduction of cobalt and cobalt oxide is firstly studied by measuring the in-situ temperature of the Co(NO3)2-coated carbon fiber paper (CFP) substrate during IPWL irradiation and analyzing the crystal structures of the IPWL-irradiated samples. Cobalt nanoflakes and cobalt oxide nanoparticles are synthesized on the surface of the CFP substrate by irradiating IPWL for 10 ms at ambient temperature and pressure with various energy densities from 10 to 30 J cm−2. The Co3O4 nanoparticle/CFP and Co nanoflake/CFP samples are further utilized as an electrode, and each electrode exhibits high specific capacity of 29 and 73 mA h g−1, respectively, at a current density of 1 A g−1. Since this novel photothermal reduction technique is applicable to other transition metals and metal oxides, it is a promising method for not only energy storage systems, but also for energy generation applications, filters, sensors, and catalysis systems.

Quantitative indication of the process of forming a complex comes from the evaluation of the stability constants, which characterize the equilibria corresponding to the successive addition of ligands. A method, involving the use of paper electrophoretic technique is described for the study of binary complex system in solution. Present method is based upon the migration of a spot of metal ions on a paper strip at different pH’s of background electrolyte. A graph of pH against mobility gives information about the binary complexes and permits calculation of their stability constants. The first and second stability constants of [Be(II)-homoserine] and [Co(II)-homoserine] complexes were found to be (7.13 ± 0.02; 6.11 ± 0.09) and (4.27 ± 0.07; 3.47 ± 0.11) (logarithm stability constant values) for Be(II) and Co(II) complexes, respectively, at ionic strength of 0.1 mol/L and a temperature of 35 °C.

We present a high-capacity pseudocapacitor based on a hierarchical network architecture consisting of Co(3)O(4) nanowire network (nanonet) coated on a carbon fiber paper. With this tailored architecture, the electrode shows ideal capacitive behavior (rectangular shape of cyclic voltammograms) and large specific capacitance (1124 F/g) at high charge/discharge rate (25.34 A/g), still retaining ~94% of the capacitance at a much lower rate of 0.25 A/g. The much-improved capacity, rate capability, and cycling stability may be attributed to the unique hierarchical network structures, which improves electron/ion transport, enhances the kinetics of redox reactions, and facilitates facile stress relaxation during cycling.

Catalytic performances of isopropanol combustion and bed pressure drop in structured fixed bed reactor composed of cobalt oxides modified ZSM-5 zeolite membrane catalysts on paper-like stainless steel fibers (Co/ZSM-5/PSSF) and traditional granular ZSM-5 zeolites catalysts were investigated in this paper. Both of the catalyst samples were fabricated by wetness impregnation method and were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometer (EDS) mapping and the N 2 adsorption/desorption isotherm analyses. The result of EDS mapping revealed that cobalt oxides dispersed well on ZSM-5/PSSF. The Co/ZSM-5/PSSF catalyst display superior catalytic activity to granular Co/ZSM-5 catalyst, 50% and 90% isopropanol conversion temperatures over Co/ZSM-5/PSSF reduced 107 °C and 51 °C, respectively, compared with those over granular Co/ZSM-5 catalysts. The apparent activation energy for isopropanol combustion over Co/ZSM-5/PSSF (90 kJ/mol) was much lower than that over granular Co/ZSM-5 (134 kJ/mol). When the face velocity increased to 14.9 cm/s, the bed pressure drop of reactor filled with only Co/ZSM-5/PSSF catalysts was 9.5% of that of reactor filled with only granular Co/ZSM-5 catalysts. The ZSM-5 zeolite membrane on paper-like stainless steel fibers support provide good dispersion for cobalt oxides and Co/ZSM-5/PSSF show superior catalytic efficiency of isopropanol combustion and produced lower bed pressure drop in reactor compared with granular ZSM-5 zeolites.

A spraymethod is proposed to improve the catalytic properties of ceramic papers to be used as catalytic lters for removing diesel soot particles. Small particles of Ce and Co oxides, acting as active centers for the combustion of the soot retained by the lter, are efciently and homogeneously deposited. On the contrary, the application of the conventional dripmethod results in bigger particlesmainly agglomerated at the crossings between the bers of the ceramic paper. As a result, catalytic papers prepared by the spraymethod exhibitmuch higher performance with soot combustion temperatures decreased by ~30 °C. Fil: Tuler, Fernando Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Gaigneaux, Eric M.. Université Catholique de Louvain; Bélgica Fil: Miro, Eduardo Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Milt, Viviana Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentina Fil: Debecker, Damien P.. Université Catholique de Louvain; Bélgica

The high-energy Li S battery suffers from poor cycling performance due to the shuttle effect of the polysulfides. Strategies must be adopted to suppress the diffusion of polysulfides into the electrolyte in Li S battery. In this work, for the first time, we adopt hydrophilic carbon paper anchored by hierarchically porous cobalt disulfides as the interlayer for capturing polysulfides through physical absorption and chemical bonding. Hierarchical pores can physically adsorb polysulfides, and moreover cobalt disulfide can trap the polysulfides by forming strong chemical interaction. The sulfur-graphene composite with a sulfur content of 70.5% delivers a high initial capacity of 1239.5 mAh g−1 at 0.2 C and retains a reversible capacity of 818 mAh g−1 after 200 cycles. In spite of a little capacity contribution by the insertion of lithium ions into cobalt disulfide for the initial cycles, it disappears in the subsequent cycling. Therefore, the as-developed porous transition metal disulfides on carbon paper as the interlayer could significantly enhance the cycling performance of Li S batteries.

A new method paper electrophoresis, involving the use of a ionophoretic technique is described for the study of Be(II) and Co(II) biologically important binary complexes with norvaline in solution. The stability constants of ML and ML 2 complexes of Be(II) – norvaline and Co(II) – norvaline systems have been found to be (7.19 ± 0.02, 5.93 ± 0.09) and (4.61 ± 0.12, 2.83 ± 0.05) (logarithm stability constant values), respectively at ionic strength of 0.1 mol L -1 and a temperature of 35 0 C. Keywords : Paper electrophoresis technique; Overall mobility; Beryllium(II) complexes; cobalt(II) complexes; Norvaline; stability constants. e-mail: brijtew@yahoo.com INTRODUCTION For the general case of the complex ML n , the stepwise formation or stability constants (K n ) are:where M and L are metal cation and ligand anion, respectively. For the calculation of total concentration of final complex product (ML n ), the overall formation constant is used. [ML n ]b n =