Carmen S D Rodrigues

University of Porto | UP · Departamento de Engenharia Química

The removal of p-nitrophenol (PNP) from wastewater was evaluated by the activated persulfate process using different materials - carbon xerogels (XG), carbon nanotubes (CNT), and activated carbon (AC) -, and also using such materials doped with nitrogen (XGM, CNTM and ACM). These carbon materials were impregnated with 2 wt.% of iron and tested in t...

In this study, a combination of coagulation/flocculation and Fenton processes was studied as tertiary treatment in order to generate treated water susceptible to reuse. The combination of both processes has never been applied in disinfection of real urban wastewater. The best removals of turbidity and enterobacteria were achieved when applying a co...

The degradation of toluene from a gas stream by the heterogeneous Fenton process was evaluated over a carbon-coated monolith impregnated or not with iron as catalyst in a bubble column reactor (BCR). The carbon-coated monolith support (CM) was prepared by chemical vapor deposition and the catalyst (CM impregnated with iron – herein called CM-Fe) by...

A novel approach for the treatment of volatile organic compounds from gaseous streams was developed. In order to accomplish this, a semi-batch bubble reactor was used, aiming to assess the toluene (selected as model compound) degradation from gaseous streams via heterogeneous Fenton oxidation. Activated carbon-based catalysts—metal-free or iron-imp...

Processes optimisation is one of the main issues to take into account for the design of new chemical processes applied to wastewater treatment plants (WWTPs). Particularly, it can be achieved using design of experiments (DoE) tools, and can represent progress in the process performance and cost reduction. In this work, an advanced oxidation process...

The degradation of a model compound (p-nitrophenol - PNP) was evaluated by a heterogeneous Fenton process using iron supported on N-doped activated carbon (Fe-ACM) as catalyst in a continuous stirred tank reactor - CSTR. The stability of the catalyst was verified during reutilization and long-term tests, without any iron loss from the catalyst. The...

To address the increasing contamination of aquatic environments and incidence of waterborne diseases, advanced oxidation processes with activated persulfate have emerged as tools to inactivate wastewater microorganisms and contaminants. In this work, the disinfection of a secondary effluent from a wastewater treatment plant by iron-based persulfate...

In the present work, the degradation of p-nitrophenol (PNP) and its mineralization by a UV/Vis-based persulphate activation process was investigated. Firstly, a screening of processes as direct photolysis, persulphate alone and persulphate activated by radiation was performed. The incidence of radiation demonstrated to have an important role in the...

The present study assesses the treatability of a real industrial wastewater (WW) with a high organic load (chemical oxygen demand (COD) above 5800 mgO2 L⁻¹) by photo-Fenton’s oxidation with the goal of improving the organic matter degradation reached previously, in another work, where the Fenton process was applied in a bubbling reactor. Thus, the...

The degradation of p-nitrophenol (PNP), which is listed as a priority pollutant by the Environmental Protection Agency (EPA), was investigated in this work by the activated persulfate oxidation. Different forms of persulfate activation (namely thermal, by medium basification and with an iron salt catalyst) were evaluated, apart from founding the be...

Background Photocatalytic degradation of Orange II (OII) dye has been carried out with commercially available materials, namely sodium Y zeolite (NaY), ammonium Y zeolite (NH4Y) and reduced graphene oxide (RGO). The catalysts were characterized by N2 adsorption at ‐196 °C, pH at the point of zero charge (pHpzc) and ultra violet/visible (UV/Vis) dif...

This study reports a new perspective for the simultaneous oxidation of a volatile organic compound (VOC) – a toluene gas stream – and a real industrial liquid effluent by the Fenton's process; for that, a lab-scale bubbling reactor, operating in semi-continuous mode, was used. A parametric study was carried out to evaluate the effect of the aqueous...

In the present study, bubbling reactors (BRs) were chosen to design a new procedure for real industrial wastewater (WW) treatment by Fenton's oxidation. The process was carried out in BRs under batch mode for the treatment of a WW with a high organic load (chemical oxygen demand (COD) above 7000 mgO2/L), being the efficient mixing of the liquid pha...

A lab scale bubble reactor (BR) configuration was employed to evaluate the degradation of gaseous toluene by Fenton’s oxidation under semi-batch mode operation (i.e., with continuous gas bubbling in the liquid phase where organics oxidation is carried out). A parametric study was performed for evaluating the effect of Fenton’s process operating par...

Biodigested coffee processing wastewater (CPW) presents a high organic load and does not meet the limits imposed by legislation (namely in Brazil) for discharge into water bodies. Anaerobic digestion generally cannot provide a satisfactory organic matter reduction in CPW as a significant fraction of recalcitrant compounds still persists in the trea...

The efficiency of Fenton/Fenton-like processes on the oxidation of organic matter from real olive mill wastewater (OMW) is described. Tests were performed in lab-scale batch reactors and the influence of different operational parameters was evaluated, namely: type of iron salt, effect of pH readjustments during the reaction, reactants addition meth...

Nowadays, there is an increasing interest in the development of promising, efficient, and environmentally friendly wastewater treatment technologies. Among them are the advanced oxidation processes (AOPs), in particular, catalytic wet peroxidation (CWPO), assisted or not by radiation. One of the challenges for the industrial application of this pro...

Invited Lecture performed by Prof. Dr. Miguel Madeira (LEPABE, FEUP).

Activated carbon (AC), carbon xerogel (XG), and carbon nanotubes (CNT), with and without N-functionalities, were prepared. Catalysts were obtained after impregnation of these materials with 2 wt.% of iron. The materials were characterized in terms of N2 adsorption at −196 °C, elemental analysis (EA), and the pH at the point of zero charge (pHPZC)....

Degradation of total phenol (TPh) and organic matter, (expressed as total organic carbon TOC), of a simulated olive mill wastewater was evaluated by the Fenton oxidation process under batch and continuous mode conditions. A mixture of six phenolic acids usually found in these agro-industrial wastewaters was used for this purpose. The study focused...

The aim of this study was to assess the degradation and mineralization of hydroquinone (HQ) by the Fenton’s process in a bubble column reactor (BCR). The effect of the main operating variables, namely, air flow rate, effluent volume, hydrogen peroxide (H2O2) concentration, catalyst (Fe²⁺) dose, initial pH, and temperature, were assessed. For all ai...

Nos últimos anos as principais agendas ambientais mundiais não têm poupado esforços para alertar sobre o perigo da geração e descarga no meio ambiente de diversos tipos de efluentes. As indústrias químicas, tais como as petroquímicas, têm um papel importante nesta temática com produções diárias de grandes quantidades de efluentes líquidos e gasosos...

This review aims to provide insight and highlight recent research trends about the treatment of gaseous and liquid effluents by advanced oxidation processes (AOPs) in bubble column reactors (BCRs), which has become an important technology to ensure efficient degradation of different types of pollutants. UV/ H2O2, Fenton, and photo-Fenton processes...

Background The aim of this study is to test different supports on which to deposit Au nanoparticles and to determine the most suitable for Orange II (OII) dye degradation by a photo‐assisted wet peroxidation (PWPO) process. The catalysts used (Au‐Fe2O3, Au‐TiO2, Au‐ZnO and Au‐Al2O3) were prepared by the deposition–precipitation method; a reference...

This paper reports on a study of the oxidation of p-nitrophenol (PNP) in a bubble column reactor (BCR). The use of the air stream aimed to provide perfect mixing in the liquid phase, which was successfully achieved and checked experimentally; there were no concentration gradients along the column, even at the lowest air flow rate used (Q 1⁄4 1 mL/m...

The treatment of several industrial effluents, such as textile, pharmaceutical, and phenol-containing wastewaters, often face limitations toward conventional treatment processes. Solutions for such problematic include the use of several advanced oxidation processes (AOPs) and particularly the Fenton one. However, most of the research has been focus...

Three different synthetic textile dyeing wastewaters were treated by a chemical coagulation/flocculation process, using ferric sulphate as coagulant. Polyacrylamide (Magnafloc 155) and polyamine (Superfloe C-573) based flocculants were applied. The influence of pH (between 3.5 and 10.4) and Fe³⁺ concentration (from 15 to 4000 mg/L) in both color an...

Activated carbons with different surface chemical properties were used as adsorbents or as catalysts for p-nitrophenol (PNP, 500 mg/L) removal by adsorption or wet peroxidation processes, respectively. The surface chemical properties of the support play an important role in PNP adsorption and in the catalytic performance of the respective iron-supp...

The olive oil industry is responsible for the generation of large amounts of untreated wastewater, commonly known as olive mill wastewater (OMW). Management of these effluents is a complex subject, not only due to the seasonality and geographically diffuse nature of olive oil production, but also because of their toxicity and high pollution potenti...

Application of the Fenton process in a bubble column reactor for hydroquinone degradation

The degradation of Orange II was evaluated by wet peroxide oxidation using gold nanoparticles supported on Fe2O3, TiO2, ZnO and Al2O3 as catalysts, in a slurry batch reactor. Materials were prepared by the same deposition-precipitation method, which yielded well-dispersed nanosized gold particles (2.2 to 5.5 nm). A commercial catalyst (Au/Fe2O3 sup...

4-Nitrophenol degradation by photo-assisted Fenton process

The post-treatment of biodigested sugarcane vinasse was envisaged in the present study following three different approaches: i) coagulation/flocculation - Approach 1; ii) combination of coagulation/flocculation with photo-Fenton reaction - Approach 2; iii) coagulation/flocculation followed by biological degradation and photo-Fenton reaction - Appro...

The efficiency of individual and integrated processes applied to organic matter reduction and biodegradability improvement of a biodigested sugarcane vinasse wastewater was assessed. Strategies considered were Fenton’s oxidation (Strategy 1), coagulation/flocculation (Strategy 2) and the combination of both processes (coagulation/flocculation follo...

The efficiency of individual and integrated processes applied to organic matter reduction and biodegradability improvement of a biodigested sugarcane vinasse wastewater was assessed. Strategies considered were Fenton’s oxidation (Strategy 1), coagulation/flocculation (Strategy 2) and the combination of both processes (coagulation/flocculation follo...

Although alkaline hydrolysis emerges as an alternative process to treat healthcare waste (HCW), information about its emissions is scarce, namely as regards effluents production. This work aims to characterize the effluents from alkaline hydrolysis tests with samples of components usually present in HCW, under a temperature of 110°C and with 1 M Na...

The degradation of a model dye compound (Orange II) was evaluated by wet peroxide oxidation using gold supported on alumina (Au/Al2O3) as a catalyst, in a slurry batch reactor. The material was prepared by the deposition-precipitation method, which yielded nanosized gold particles well dispersed on the support, with a mean particle size of 3.6 nm....

The treatability of an acrylic textile dyeing wastewater by combination of heterogeneous Fenton’s oxidation and biological degradation was evaluated in this work. In the oxidation stage, performed in a catalytic continuous stirring tank reactor (CSTR), it was evaluated the effect of some operating conditions, namely the type of catalyst used (Fe-co...

Study about the 4-nitrophenol treatment by Fenton process in batch reactor.

This work is the first known report dealing with the heterogeneous Fenton-like process in a continuous stirred tank reactor. A Fe/ZSM-5 zeolite was used as catalyst for degradation of an azo dye (Orange II, OII)-containing solution. A parametric study was carried out to evaluate the effect of the main operating conditions in the basket reactor perf...

Color and organic matter removals from acrylic, cotton and polyester dyeing wastewaters were evaluated by biological oxidation in a Sequential Batch Reactor (SBR) and by integration of Fenton’s reaction with SBR. Raw and chemically oxidized pre-treated wastewaters were fed to the biological reactor during 10 cycles (i.e., up to pseudo-steady state...

This study aims to investigate the efficiency of individual and integrated processes applied to organic matter abatement and biodegradability improvement of a polyester dyeing wastewater, namely coagulation/flocculation combined with Fenton's reagent (Approach 1), Fenton oxidation alone (Approach 2) and its integration with coagulation/flocculation...

The organic matter mineralization, decolorization, biodegradability improvement, and toxicity reduction of an industrial cotton dyeing wastewater were investigated. Different treatment approaches, including single and integrated processes, were studied, namely, coagulation/flocculation per se and its combination with Fenton oxidation (approach 1),...

New strategies were herein applied for treating a cotton dyeing wastewater: coagulation/flocculation followed by Fenton's oxidation - Approach 1, Fenton process per se - Approach 2, and Fenton followed by coagulation/flocculation - Approach 3, aiming reducing chemicals consumption. Regarding the cost analysis, which is crucial for deciding on the b...

The degradation via the photo-Fenton process of dyes and organic compounds present in acrylic, cotton, and polyester dyeing wastewaters was investigated, aiming at reducing the consumption of chemicals, as compared to the dark Fenton process, while simultaneously minimizing the energy costs by using simulated solar radiation. The reduction of the h...

The coagulation/flocculation treatment using FeSO4 x 7H2O as a coagulant is evaluated in this work for the removal of organic compounds and colour from synthetic effluents simulating the cotton, acrylic and polyester dyeing wastewaters. The coagulant dose, temperature, pH, stirring speed and stirring time that maximized the removal of dissolved org...

Fenton's reagent oxidation was employed for organic matter and color removal, along with biodegradability improvement, of a synthetic acrylic dyeing wastewater, previously treated by coagulation/flocculation. The initial iron load in the Fenton's stage varied from the residual soluble iron concentration resulting from the coagulation/flocculation p...

The removal of organic compounds and colour from a synthetic effluent simulating a cotton dyeing wastewater was evaluated by using a combined process of Fenton's Reagent oxidation and biological degradation in a sequencing batch reactor (SBR). The experimental design methodology was first applied to the chemical oxidation process in order to determ...

Chemical oxidation by Fenton's reagent of a reactive azo dye (Procion Deep Red H-EXL gran) solution has been optimized making use of the experimental design methodology. The variables considered for the oxidative process optimization were the temperature and the initial concentrations of hydrogen peroxide and ferrous ion, for a dye concentration of...

The aim of this work was to study the possibility of treating an industrial semiconductor wastewater by combining physical and chemical methods. The combined treatment consisted of pH adjustment to 2 followed by filtration and then chemical oxidation with Fenton reagent over the resulting filtered wastewater. In chemical oxidation treatment, the is...

Tese de Mestrado. Mestrado em Engenharia do Ambiente. Faculdade de Engenharia da Universidade do Porto. 2007