Modified diatomites for Fenton-like oxidation of phenol

Raw diatomites were modified by acid or base treatments; addition of Fe or Cu species through the incipient wet impregnation method (IWI) and calcination at 700 °C. Samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM-EDX), Mossbauer spectroscopy, point of zero charge (PZC), pyridine temperature programme desorption (TPD), themogravimetric analysis (TGA) and BET surface area determination. According to characterization results, four samples were selected: simply calcined Diatom (D), iron added (Fe-D), acid treated Fe reimpregnated (H-Fe-D) and copper added (Cu/Fe-D). Materials were tested as catalysts for the peroxidation of phenol solutions (1000 mg/L) in a batch laboratory reactor, at different operating conditions in 5 h tests. D, Fe-D and H-Fe-D samples allowed complete phenol removal under all the operating range studied. At optimum conditions, TOC conversions of 50–55% were obtained. Metal ions added through the IWI procedure resulted more labile than metal present originally. The acidic treatment favored the initiation of the reaction showing a reduction of the induction period at almost neutral initial pH. The Fe-D catalyst exhibited poor performance, lower reactions rates and higher Fe leaching. Conversely, high TOC conversions (80%) were achieved with Cu/Fe-D, however, Cu leaching was excessive (12.7%). D and H-Fe-D samples were used in consecutive runs (up to 20 h) maintaining phenol conversion and TOC reduction. Overall, a good performance was obtained, even comparable to more sophisticated Fe catalysts.Fil: Inchaurrondo, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ramos, Cinthia Paula. Comisión Nacional de Energía Atómica. Gerencia del Área de Seguridad Nuclear y Ambiente. Gerencia de Química (CAC); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zerjav, G.. National Institute Of Chemistry; EsloveniaFil: Font, J.. Universitat Rovira I Virgili; EspañaFil: Pintar, A.. National Institute Of Chemistry; EsloveniaFil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Orange II removal by a horseradish peroxidase immobilized onto chemically modified diatomites is a combination of adsorption and oxidation processes

In this work, a horseradish peroxidase (HRP) was immobilized onto diatomites by covalent bonding. Results indicated that the enzyme loading increased when diatomites were modified with (3-Aminopropyl) triethoxysilane (APTES) and glutaraldehyde. The immobilization was confirmed by SEM/EDX, XRD, DRIFT, and TGA analysis. Higher HRP concentrations of the immobilization solution and immobilization time had also a positive effect on the enzyme loading. Orange II (OII) adsorption onto diatomites and oxidative catalytic activity was evaluated. Results demonstrated that diatomites had a low OII adsorption capacity. However, under the presence of hydrogen peroxide, the dye removal was highly increased due to the catalytic activity of the immobilized HRP. A mathematical model that adequately describes the simultaneous adsorption and enzymatic oxidation of OII in batch tests was developed. Finally, immobilized diatomites were tested in the decolourization reaction of Orange II in a fixed-bed column reactor. Column results demonstrated that the immobilized HRP remained active for at least 12 h during three sequential OII removal tests.Fil: Morales Urrea, Diego Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; ArgentinaFil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; ArgentinaFil: Contreras, Edgardo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Prussian blue onto activated carbon as a catalyst for heterogeneous fenton-like processes.

The main goal of this contribution is the development of a new heterogeneous Fenton-like oxidation system based on Prussian Blue supported over a commercially available granular activated carbon (GAC). The catalysts were prepared following basically three different approaches: (i) Prussian Blue (Fe3[Fe(CN)6]2) particles adsorbed onto the GAC by impregnation, (ii) Prussian Blue nanoparticles (PBNP) prepared ex-situ and adsorbed onto the GAC; and (iii) PBNP prepared in-situ onto the GAC. The catalysts were characterized by SEM, EDS, BET surface area and Fe content. Their performance in the catalytic wet peroxide oxidation of a model azo dye, Orange G, was tested in a batch lab-scale stirred reactor. Activity and stability runs were carried out and analyzed in terms of dye discoloration, Total Organic Carbon removal, UV-vis spectra and degree of iron leaching.Fil: Doumic, Lucila Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingenieria; ArgentinaFil: Salierno, Gabriel Leonardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Cassanello, Miryan C.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingenieria; ArgentinaFil: Ayude, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingenieria; Argentin

On disclosing the role of mesoporous alumina in the ozonation of sulfamethoxazole: Adsorption vs. Catalysis

Ordered mesoporous alumina (MA) and Fe-doped MA were synthesized by evaporation-induced self-assembly and tested for the ozonation of sulfamethoxazole (SMX). The synthesis methodology produced MA whose surface and structural properties exceeded those of commercial types displaying a BET surface area of 263 m2/g, a pore volume of 0.8 cm3/g and aligned cylindrical pores of c.a. 10 nm. The ozonation of SMX (20 mg/L) was performed in a semibatch stirred tank reactor at: T = 22 °C, [O3]gas = 10 mg/L, Qgas = 42 L/h NTP, [solid] ≈ 1 g/L, t = 120 min. Single ozonation achieved fast and complete SMX removal and mineralized up to 35% of the organics at neutral pH. The addition of MA or Fe-doped MA did not affect the removal rate of SMX, but did achieve a remarkable TOC removal up to 86% at acid pH. However, under the selected operating conditions, ferric species did not improve the removal of organic matter. Then, the adsorption and catalytic contribution of MA was evaluated in specifically-designed experiments. While SMX adsorption was low, its oxidation intermediates did adsorb onto MA surface. Despite the high ability of the materials to decompose ozone, the results revealed that the by-products adsorption is the prevailing process for the TOC removal. After four successive reuses, MA reduced its adsorption performance due to chemisorption of carboxylates. Nevertheless, the worn material was regenerated by direct ozonation in gas phase. In addition, primary transformation products were identified by LC–ESI–TOF–MS and the scavenging effect of the water matrix was assessed using bottled water and a real secondary wastewater.Fil: Di Luca, Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; ArgentinaFil: Inchaurrondo, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; ArgentinaFil: Marcé, Mireia. Universidad Central de Barcelona; EspañaFil: Parra, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Esplugas, Santiago. Universidad Central de Barcelona; EspañaFil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; Argentin

Dryout phenomenon in the periodic operation of a trickle bed reactor

Periodic operation was investigated for the hydrogenation of aplpha-methylsyrene to cumene over 0.5% Pd on alumina spheres. The effect of several variables such as gas flow rate, gas and liquid composition, and liquid feed temperature on unsteady-state liquid flow modulation in a Trickle Bed Reactors is studied. These parameters affect the depletion time of the volatile reactant as well as the temperature profiles of the dry cycle. A criterion is presented that allows for an estimation of the maximum temperature during the dry cycle based on mass and energy balances.Fil: Ochoa, J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Cechini, Jorge Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Nanofiltration of partial oxidation products and copper from catalyzed wet peroxidation of phenol

The aim of this work is to study the combination of Catalytic Wet Peroxide Oxidation (CWPO) and nanofiltration processes in the treatment of phenol solutions. A home-made Cu-chitosan/Al2O3 catalyst was applied for this purpose. The effluent from CWPO usually contains some metal leached from the catalyst in addition to latter oxidation intermediates (short chain organic acids). Downstream nanofiltration is used to retain the metal leached from the catalyst, which would result in secondary pollution and negatively impact on a possible subsequent biological treatment step. The CWPO was performed in a batch recycle trickle bed reactor packed with the catalyst. The final distribution of intermediates was identified by HPLC. Cross flow filtration experiments using either model solutions containing phenol and the main intermediates (succinic, malonic, maleic and oxalic acid), with and without Cu(II) or the effluent of the CWPO reaction were performed using a NF90 membrane. When all intermediates were combined, the rejection of copper reached over 95% while an acceptable maximum of 10% of permeate flux loss, compared with the initial flux, was maintained. Nanofiltration of a real CWPO effluent gave a higher copper recovery of 97%. Thus, the permeate toxicity was highly reduced. In addition, after 4 h of filtration, only a 5% of flux loss was observed, which guarantees a stable filtration for days.Fil: Inchaurrondo, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina; Universidad Nacional de Mar del Plata. Facultad de Ingenieria; Argentina;Fil: Font, J.. Universitat Rovira I Virgili; España;Fil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentina; Universidad Nacional de Mar del Plata. Facultad de Ingenieria; Argentina

Bacillus subtilis as a bioindicator for estimating pentachlorophenol toxicity and concentration

Pentachlorophenol (PCP) and its sodium salt (Na-PCP) are extremely toxic chemicals responsible forimportant soil and groundwater pollution, mainly caused by wastes from wood-treatment plants, because chlorinated phenols are widely used as wood preservatives. The methods most commonly used for routine analysis of pesticides such as PCP and Na-PCP are high-performance liquid chromatography (HPLC) and gas chromatography– mass spectroscopy (GC–MS). A variety of rapid biological screening tests using marine organisms, bioluminescent bacteria, and enzymes have also been reported. In this study, rapid biological screening analysis using Bacillus subtilis was developed, to assess the biodegradation of PCP and its by-products in liquid samples. An empirical model is proposed for spectrophotometric analysis of Na-PCP concentration after growth of Bacillus subtilis.Fil: Ayude, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Okada, Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Ingeniería Bioquímica; ArgentinaFil: González, J. F.. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Ingeniería Bioquímica; ArgentinaFil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Murialdo, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Ingeniería Bioquímica; Argentin

Catalyst reutilization in phenol homogeneous cupro-Fenton oxidation

The catalytic wet peroxide oxidation of phenol (1 g/L) was performed in a laboratory batch reactor using the cupro-Fenton homogeneous reaction. At 70 °C and using 200 mg/L of Cu (II) complete phenol removal, high TOC reduction (ca. 85%) and efficient use of hydrogen peroxide were achieved. A lumped kinetic model that accounts for organics mineralization and peroxide consumption was developed to predict reactants and total organic carbon profiles. After the reaction step, Cu(II) was recovered by precipitation with NaOH; Cu(II) concentration in the discharged liquid was always less than the 1 mg/L. The sludge was reused in subsequent reaction steps with minor fluctuations in the catalytic activity. The combination of the cupro-Fenton reaction with an alkaline precipitation procedure allows lower operational costs and helps to reduce the toxicity of the treated wastewater.Fil: Inchaurrondo, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; ArgentinaFil: Contreras, Edgardo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; ArgentinaFil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentin

Enhancing performance of a trickle bed reactor at low liquid flowrates

The impact of liquid volatility, gas solubility, mass transfer and kinetics-diffusion on the reactor performance at incomplete wetting was observed. Three different reactor zones of prepacking inert section, catalytic bed and post packing inert section were considered. The rate enhancement found under partial wetting was considered using a one-dimensional model that takes into account the effect of gas and liquid flowrates, liquid volatility, gas solubility and kinetic parameters.Fil: Ochoa, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Castellari, Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Cechini, Jorge Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Volcanic Ash Leachate as a Low-Cost Catalyst for Fenton-Like Reactions

This work deals with the reduction of operating costs of the Fenton-like oxidation of the azo dye Orange II (OII) using volcanic ash leachate as the catalyst. The effect of the volcanic ash concentration and temperature on the total iron concentration of the leachate was studied. Results demonstrated that Fe(II) represented 83 ± 6% of the leachate total iron. Using the obtained leachate as the catalyst for the oxidation of OII, different temperatures (35 to 65 °C), and oxidant feed strategies (batch, pulse feed, or fed-batch) were studied. Hydrogen peroxide (H2O2), total organic carbon concentration (TOC), and UV?Vis spectrum of the reaction mixture were measured as a function of time, while oxidation-reduction potential (ORP)measurements were recorded continuously. Depending on the tested conditions, maximum TOC conversions ranged from 40 to 70%, and H2O2 efficiencies ranged between 3 and 4.6 mgC/mmol H2O2. In addition, ORP measurement allows determining operative conditions that minimize oxidant consumption. Although ORP-based control strategies of fed-batch reactors require more sophisticated equipment in comparison with a batch reactor, they offered more variables to control the process, and therefore, to optimize operating costs.Fil: Rodríguez Simón, Carlos Norberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Haure, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Contreras, Edgardo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin