Textiles

A review of the literature published in 2008 on topics relating to wastewater treatment issues and technologies in the textile industries is presented. After a brief overview of the BATTLE project, the review is divided into the following sections: physico-chemical, biological and combined processes

Advances in Pillared Clays and Similar Materials

Since the first works introducing the aluminum intercalated clay family in the early 1970s, interest in the synthesis of Pillared InterLayered Clays (PILC) has increased tremendously, especially research into their properties and energetic and environmental applications. After our comprehensive reviews and book on the synthesis and catalytic applications of these materials, new references have appeared in the literature and the interest in this field is continuously increasing. The aim of this Special Issue is to collect the recent advances developed considering this family of solids

Enzymatic treatment of azo-dyes with soybean peroxidase

The presence of azo-dyes in water bodies represents an environmental problem due to their recalcitrant, toxic and in some cases carcinogenic characteristics. In this dissertation, a more complete analysis is presented which includes color removal, dye conversion, total amines (as aniline) and product degradation. Enzymatic treatment with soybean peroxidase (SBP) was studied to decolorize and degradate two impure azo-dyes, Acid Blue 113 (AB113; a di-azo dye) and Direct Black 38 (DB38; a tri-azo dye). A single-step process (direct enzymatic treatment) and a two-step process (zero-valent iron (Fe°) reduction followed by enzymatic treatment) were compared to obtain the optimal conditions of pH, H2O2 concentration, enzyme concentration and reaction time for maximum decoloration, dye and products degradation as well as total amines removal. More than 95% decoloration and dye degradation was achieved for both dyes after single- and two-step processes. A two-step process was preferred for DB38, because, after Fe° reduction, the products (aniline and benzidine) were SBP substrates which needed low SBP and H2O2 concentrations for 95% removal. The lowest KM value (data obtained from Michaelis-Menten plot) was for a simple and highly pure reference dye, Crocein Orange G (COG), followed by AB113 and then DB38. Evidence for azo-cleavage of COG due to direct enzymatic treatment was obtained, identified and quantified by high-performance liquid chromatography (HPLC) where aniline was produced. Mass spectrometry was used to confirm the presence of aniline after treatment. An alternative for reducing the number of experimental runs during optimization and obtain valuable statistical parameters, response surface methodology (RSM; software program Minitab), was used to optimize and characterize the decoloration of AB113 and DB38. These methods showed that the parameters: pH, H2O2 and enzyme concentrations were statistically significant in the removal of azo-dye; in addition, the presence of curvature in the response surface, indicated a preference for a second-order model. Decoloration of more than 95% was obtained by the RSM model. For AB113 the optimal response obtained with Minitab model was 5.7 % and the experimental value under the same conditions was 8.0% (2.3% difference) while for DB38 the optimal Minitab response was 3.6% and 5.1% for the experimental value (1.5% difference). Equations were obtained to determine percent color remaining within the study area (for AB113 pH 3.6-5.3; enzyme 1.0-2.0 U/mL; H2O2 1.0-3.0 mM and for DB38 pH 3.0-5.0; enzyme 2.5-3.5 U/mL; H2O2 2.5-3.5 mM). A positive RSM result shows the reduction of experimental runs compared to the optimization of one-parameter-at-a-time which represent diminished analysis time

Advanced oxidation processes identification by means of microwave radiation for wastewater treatment

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid. Facultad de Ciencias, Departamento de Ingeniería Química. Fecha de lectura: 26-04-2019La realización de este trabajo ha sido posible gracias al apoyo económico del Ministerio de Economía y Competitividad con los proyectos CTQ2013-41963-R y CTM2016-76454-R, además del contrato predoctoral BES-2014-067598 cofinanciado por el Fondo Social Europeo y las ayudas económicas de movilidad predoctoral EEBB-I-17-12532 y EST2019-013106-I Asimismo, han contribuido en la financiación de este trabajo la Comunidad Autónoma de Madrid a través del proyecto REMTAVARES S2013/MAE-2716 y Campus France con una beca de movilidad predoctoral dentro del programa Make Our Planet Great Again

Clay Science and Technology

This book presents the state-of-the-art results of synthesis, characterization, modification, and technological applications of clays, clay minerals, and materials based on clay minerals, such as polymer–clay nanocomposites and clay hybrids. It also presents some important results obtained in the broad area of clays and clay materials characterization. Moreover, this book provides a comprehensive account of polymer and biopolymer–clay nanocomposites, the use of clay as adsorption materials of industrial pollutants, the ceramic industry, and the physical–chemical aspects of aqueous dispersions of clay and clay minerals. This book is beneficial for students, teachers, and researchers who are interested in expanding their knowledge about the use of clays in a diverse range of fields, including nanotechnology, biotechnology, environmental science, industrial remediation, pharmaceuticals, and so on

From Fenton and ORR 2e−-Type Catalysts to Bifunctional Electrodes for Environmental Remediation Using the Electro-Fenton Process

Currently, the presence of emerging contaminants in water sources has raised concerns worldwide due to low rates of mineralization, and in some cases, zero levels of degradation through conventional treatment methods. For these reasons, researchers in the field are focused on the use of advanced oxidation processes (AOPs) as a powerful tool for the degradation of persistent pollutants. These AOPs are based mainly on the in-situ production of hydroxyl radicals (OH center dot) generated from an oxidizing agent (H2O2 or O-2) in the presence of a catalyst. Among the most studied AOPs, the Fenton reaction stands out due to its operational simplicity and good levels of degradation for a wide range of emerging contaminants. However, it has some limitations such as the storage and handling of H2O2. Therefore, the use of the electro-Fenton (EF) process has been proposed in which H2O2 is generated in situ by the action of the oxygen reduction reaction (ORR). However, it is important to mention that the ORR is given by two routes, by two or four electrons, which results in the products of H2O2 and H2O, respectively. For this reason, current efforts seek to increase the selectivity of ORR catalysts toward the 2e(-) route and thus improve the performance of the EF process. This work reviews catalysts for the Fenton reaction, ORR 2e(-) catalysts, and presents a short review of some proposed catalysts with bifunctional activity for ORR 2e(-) and Fenton processes. Finally, the most important factors for electro-Fenton dual catalysts to obtain high catalytic activity in both Fenton and ORR 2e(-) processes are summarized.Ministry of Science and Innovation, Spain (MICINN) Spanish Government PID2021-127803OB-I00Junta de Andalucia B.RNM.566.UGR2

Developing persulfate-activator soft solid (PASS) as slow release oxidant to remediate phenol-contaminated groundwater

The research objective was to develop a persulfate-activator soft solid (PASS) as a biodegradable slow-release oxidant to treat phenol-contaminated groundwater. PASS was prepared by graft copolymerization of acrylic acid (AA) and acrylamide (AM) onto 1% (w/v) sodium alginate mixed with 500 mg L−1 sodium persulfate and 5 mg L−1 ferrous sulfate. The physical and chemical properties of PASS were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, the water content and swelling ratio. Various variables, including the ratio of AA/AM, pH, temperature and the type of groundwater cations affecting PS release, were investigated. The maximum PS release in DI water was 98% in the ratio of PASS 1 (AA/AM, 75/25), 96% at pH 3, 83% at 25 °C, and 80% with Na+. The major factors controlling PS release were the AA/AM ratio and pH. PASS 1 can be stable in size and shape for 6–8 days and completely degraded within 34 days. The degradation rates of 10 mgL−1 phenol using PASS produced the highest kobs values for each variable at a ratio of PASS 1 (k = 0.1408 h−1), pH 7 (k = 0.1338 h−1), 25 °C (k = 0.1939 h−1), and Ca2+ (k = 0.1336 h−1). The temperature of the groundwater was key to driving the reaction between PS and phenol. PASS 1 was applied in simulated phenol-contaminated groundwater via horizontal tanks containing Ottawa sand. The results indicated 93.2% phenol removal within 72 h in a narrow horizontal flow tank and 41.7% phenol removal in a wide horizontal flow tank with aeration

Effect of the air pressure on electro-Fenton process

Electro-Fenton process is considered a very promising tool for the treatment of waste waters contaminated by organic pollutants refractant or toxic for microorganisms used in biological processes [1-6]. In these processes H2O2 is continuously supplied to an acidic aqueous solution contained in an electrolytic cell from the two-electron reduction of oxygen gas, directly injected as pure gas or bubbled air. Due to the poor solubility of O2 in aqueous solutions, two dimensional cheap graphite or carbon felt electrodes give quite slow generation of H2O2, thus resulting in a slow abatement of organics. In this context, we report here a series of studies [7-9] on the effect of air pressure on the electro-generation of H2O2 and the abatement of organic pollutants in water by electro-Fenton process. The effect of air pressure, current density, mixing and nature of the organic pollutant was evaluated. [1] E. Brillas, I. Sirés, M.A. Oturan, Chem. Rev., 109 (2009) 6570-6631. [2] C.A. Martínez-Huitle, M.A. Rodrigo, I. Sirés, O. Scialdone, Chem. Rev. 115 (2015) 13362–13407. [3] M. Panizza, G. Cerisola, Chem. Rev. 109 (2009) 6541–6569. [4] I. Sirés, E. Brillas, M.A. Oturan, M.A. Rodrigo, M. Panizza, Environ. Sci. Pollut. Res. 21 (2014) 8336–8367. [5] C.A. Martínez-Huitle, S. Ferro, Chem. Soc. Rev. 35 (2006) 1324–1340. [6] B.P.P. Chaplin, Environ. Sci. Process. Impacts. 16 (2014) 1182–1203. [7] O. Scialdone, A. Galia, C. Gattuso, S. Sabatino, B. Schiavo, Electrochim. Acta, 182 (2015) 775-780. [8] J.F. Pérez, A. Galia, M.A. Rodrigo, J. Llanos, S. Sabatino, C. Sáez, B. Schiavo, O. Scialdone, Electrochim. Acta, 248 (2017) 169-177. [9] A.H. Ltaïef, S. Sabatino, F. Proietto, A. Galia, O. Scialdone, O. 2018, Chemosphere, 202, 111-118

Pressurized CO2 Electrochemical Conversion to Formic Acid: From Theoretical Model to Experimental Results

To curb the severely rising levels of carbon dioxide in the atmosphere, new approaches to capture and utilize this greenhouse gas are currently being investigated. In the last few years, many researches have focused on the electrochemical conversion of CO2 to added-value products in aqueous electrolyte solutions. In this backdrop, the pressurized electroreduction of CO2 can be assumed an up-and-coming alternative process for the production of valuable organic chemicals [1-3]. In this work, the process was studied in an undivided cell with tin cathode in order to produce formic acid and develop a theoretical model, predicting the effect of several operative parameters. The model is based on the cathodic conversion of pressurized CO2 to HCOOH and it also accounts for its anodic oxidation. In particular, the electrochemical reduction of CO2 to formic acid was performed in pressurized filter press cell with a continuous recirculation of electrolytic solution (0.9 L) at a tin cathode (9 cm2) for a long time (charge passed 67’000 C). It was shown that it is possible to scale-up the process by maintaining good results in terms of faradaic efficiency and generating significantly high concentrations of HCOOH (about 0.4 M) [4]. It was also demonstrated that, for pressurized systems, the process is under the mixed kinetic control of mass transfer of CO2 and the reduction of adsorbed CO2 (described by the Langmuir equation), following our proposed reaction mechanism [5]. Moreover, the theoretical model is in good agreement with the experimental results collected and well describes the effect of several operating parameters, including current density, pressure, and the type of reactor used. 1. Ma, S., & Kenis, P. J. (2013). Electrochemical conversion of CO2 to useful chemicals: current status, remaining challenges, and future opportunities. Current Opinion in Chemical Engineering, 2(2), 191-199. 2. Endrődi, B., Bencsik, G., Darvas, F., Jones, R., Rajeshwar, K., & Janáky, C. (2017). Continuous-flow electroreduction of carbon dioxide. Progress in Energy and Combustion Science, 62, 133-154. 3. Dufek, E. J., Lister, T. E., Stone, S. G., & McIlwain, M. E. (2012). Operation of a pressurized system for continuous reduction of CO2. Journal of The Electrochemical Society, 159(9), F514-F517. 4. Proietto, F., Schiavo, B., Galia, A., & Scialdone, O. (2018). Electrochemical conversion of CO2 to HCOOH at tin cathode in a pressurized undivided filter-press cell. Electrochimica Acta, 277, 30-40. 5. Proietto, F., Galia, A., & Scialdone, O. (2019) Electrochemical conversion of CO2 to HCOOH at tin cathode: development of a theoretical model and comparison with experimental results. ChemElectroChem, 6, 162-172

Preparation and evaluation of Lignocellulose-Montmorillonite nanocomposites for the adsorption of some heavy metals and organic dyes from aqueous solution

The need to reduce the cost of adsorption technology has led scientists to explore the use of many low cost adsorbents especially those from renewable resources. Lignocellulose and montmorillonite clay have been identified as potentially low cost and efficient adsorbent materials for the removal of toxic heavy metals and organic substances from contaminated water. Montmorillonite clay has good adsorption properties and the potential for ion exchange. Lignocellulose possesses many hydroxyl, carbonyl and phenyl groups and therefore, both montmorillonite and lignocellulose are good candidates for the development of effective and low cost adsorbents in water treatment and purification. The aim of this study was to prepare composite materials based on lignocellulose and montmorillonite clay and subsequently evaluate their efficacy as adsorbents for heavy metal species and organic pollutants in aqueous solution. It was also important to assess the adsorption properties of the modified individual (uncombined) lignocellulose and montmorillonite. Lignocellulose and sodium-exchanged montmorillonite (NaMMT) clay were each separately modified with methyl methacrylate (MMA), methacrylic acid (MAA) and methacryloxypropyl trimethoxysilane (MPS) and used as adsorbents for the removal of heavy metals and dyes from aqueous solution. The lignocellulose and NaMMT were modified with MMA, MAA and MPS through free radical graft polymerisation and/or condensation reactions. NaMMT was also modified through Al-pillaring to give AlpMMT. The materials were characterised by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and small angle X-ray scattering (SAXS) and characterisation results showed that the modification of the montmorillonite with MAA, MMA and MPS was successful. The modified lignocellulose and montmorillonite materials were evaluated for the adsorption of heavy metal ions (Cd2+ and Pb2+) from aqueous solution by the batch method. The adsorption isotherms and kinetics of both Cd2+ and Pb2+ onto the NaMMT clay, AlpMMT and lignocellulose materials are presented. The Langmuir isotherm was found to be the best fit for the adsorption of both heavy metals onto all the adsorbents. AlpMMT showed very poor uptake for heavy metals (both Cd2+ and Pb2+). PMMAgMMT, PMAAgMMT, PMAAgLig and PMPSgLig showed improved adsorption for both heavy metals. The mechanism of heavy metal adsorption onto the adsorbents was best represented by the pseudo second-order kinetic model. PMPSgLig, NaMMT and AlpMMT showed relatively high adsorption capacities for methyl orange, while the adsorption of neutral red was comparable for almost all the adsorbents. Neither the Langmuir model nor the Freundlich model was found to v adequately describe the adsorption process of dyes onto all the adsorbents. The pseudo second-order model was found to be the best fit to describe the adsorption mechanism of both dyes onto all the adsorbents. The modification of lignocellulose and montmorillonite with suitable organic groups can potentially produce highly effective and efficient adsorbents for the removal of both heavy metals and dyes from contaminated water. Novel adsorbent composite materials based on lignocellulose and montmorillonite clay (NaMMT) were also prepared and evaluated for the removal of pollutants (dyes and heavy metals) from aqueous solution. The lignocellulose-montmorillonite composites were prepared by in situ intercalative polymerisation, using methyl methacrylate, methacrylic acid and methacryloxypropyl trimethoxysilane (MPS) as coupling agents. The composite materials were characterised by FTIR, TGA, TEM and SAXS. SAXS diffractograms showed intercalated nanocomposites of PMMAgLig-NaMMT and PMAAgLig-NaMMT, whereas PMPSgLig-NaMMT showed a phase-separated composite and the same results were confirmed by TEM. The lignocellulose-montmorillonite composites were assessed for their adsorption properties for heavy metal ions (Cd2+ and Pb2+) and dyes (methyl orange and neutral red) from aqueous solution. Among these composite materials, only PMAAgLig-NaMMT showed a marked increase in the uptake of both Cd2+ and Pb2+ relative to lignocellulose and montmorillonite when used independently. The adsorption data were fitted to the Langmuir and Freundlich isotherms, as well as to the pseudo first-order and pseudo second-order kinetic models. The data were best described by the Langmuir isotherm and the pseudo second-order kinetic model. On the adsorption of dyes, only PMPSgLig-NaMMT showed enhanced adsorption of methyl orange (MetO) compared with lignocellulose and montmorillonite separately. The enhanced adsorption was attributed to the synergistic adsorption due to the presence of MPS, lignocellulose and NaMMT. Competitive adsorption studies were carried out from binary mixtures of MetO and Cd2+ or Pb2+ in aqueous solution. The adsorption process of MetO onto the composite material was found to follow the Freundlich adsorption model, while the mechanism of adsorption followed both the pseudo first-order and pseudo second-order models. This particular composite can be used for the simultaneous adsorption of both heavy metals and organic dyes from contaminated water. The adsorption of neutral red to the composite materials was comparable and the pseudo second-order kinetic model best described the adsorption mechanism