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Dibutyl phthalate (DBP) is one of the listed phthalic acid esters (PAEs) known as the priority toxicants which exhibit carcinogenic and teratogenic properties and is responsible for endocrine disruption. Therefore, its removal has become a matter to tackle with. In this work, the feasibility of DBP degradation by esterase and lipase enzymes obtained from various microorganisms and the immobilization of the most effective in a clayey material were investigated. Esterase from Bacillus subtilis exhibited the highest degradation efficiency reaching a complete degradation. Its immobilization onto halloysite nanotubes (HNTs) by adsorption method was studied by response surface methodology using a central composite design face-centered. The four selected factors that affect the HNT-enzyme composite generation were: pH, adsorption time, enzyme/HNT (E/H) ratio, and adsorption temperature, and the optimal conditions were determined (pH 7, time 360 min, E/H ratio 0.2, temperature 30ºC). Consequently, the activity did not significantly decrease by immobilization, and the adsorption efficiency and relative activity were determined to be 73.15% and 82.7%, respectively. Besides, the immobilization enhanced thermal and storage stability. As for enzyme reusability, after 7 continuous cycles, the composite maintained almost 75% of its initial activity. Both the free enzyme (1 mg/mL) and the composite degraded 100 mg/L DBP with 100% efficiency and several byproducts were detected. Moreover, the composite could be reused for 7 cycles keeping a remarkable catalytic activity. Overall, this study indicated that the HNT-enzyme composite may be used as an effective candidate for remediation of the environmental media contaminated with DBP and other PAEs. Agencia Estatal de Investigación | Ref. PCI2022-132941 Xunta de Galicia | Ref. ED431C 2021-43 Universidade de Vigo/CISUG

In this study, three CuFe-MOFs were successfully synthesized by a solvothermal process by changing the ratio of solvents, salts, or temperature. These MOFs named CuFe(BDC-NH2)R, CuFe(BDC-NH2)S, and CuFe(BDC-NH2)D showed rod-shaped, spindle-like, and diamond-like structures, respectively. The CuFe(BDC-NH2)D and CuFe(BDC-NH2)S were found to exhibit an improved PMS activation for Rhodamine B removal attaining levels around 92%. Their effective removal capability was investigated as a function of the pH, catalyst dosage, and the effect of the application of UV radiation. The best degradation system was photo-assisted activation of PMS when CuFe(BDC-NH2)D and CuFe(BDC-NH2)S were used. Under these conditions, the degradation of a mixture of antibiotic and anti-inflammatory drugs (sulfamethoxazole and antipyrine) was evaluated with the results revealing the total degradation of both drugs after 1 h. A higher antibacterial activity was attained with the system CuFe(BDC-NH2)R/PMS due to the high copper content with respect to the others. Ministerio de Ciencia e Innovación | Ref. PCI2022-132941 Ministerio de Ciencia e Innovación | Ref. PID2020-113667GBI00 Xunta de Galicia | Ref. ED431C 2021-43

The development of novel approaches to the remotion of pharmaceuticals in wastewater is a subject of concern due to their effect on living beings and the environment. Advanced oxidation processes and the use of relevant catalysts are feasible treatment alternatives that require further development. The development of suitable heterogeneous catalysts is a necessity. This work proposes the synthesis of an iron catalyst in a deep eutectic solvent (Fe-DES) composed of choline chloride and citric acid, which was physically and chemically characterized using SEM-EDS and TEM, FTIR, RAMAN, XRD and XPS. The characterisation confirmed the presence of iron in the form of hematite. Fe-DES was shown to be a multipurpose catalyst that can be applied in the removal of sulfamethoxazole as a reagent in the Fenton and electro-Fenton processes and as an activator of peroxymonosulfate (PMS) processes. After testing the catalyst with the aforementioned techniques, the best result was achieved by combining these processes in an electro-PMS, with great efficiency achieved by dual activation of the PMS with the catalyst and electric field, attaining total elimination at natural pH in 90 min. Furthermore, the degradation was confirmed by the detection of short-chain carboxylic acids (oxalic, succinic, and acetic) and reduction in toxicity values. These results confirm the suitability of Fe-DES to degrade high-priority pharmaceutical compounds. Xunta de Galicia y FEDER | Ref. ED431C 2021-43 Ministerio de Ciencia e Innovación | Ref. PCI2022-132941 Ministerio de Ciencia e Innovación | Ref. PDC2021-121394-I00

In the current study, a novel-fangled sequential approach, adsorption/electro-Fenton, was developed for the elimination of micropollutants from aqueous matrixes. Therefore, the prompt removal of a pharmaceutical, sulfamethizole, by adsorption on carbonaceous materials is proposed. After that, the concentrated solution was treated by electro-Fenton using novel synthesized perlite-based catalyst. Initially, three different carbonaceous adsorbents (pellets carbonaceous nanogel doped with iron, honeycomb carbonaceous aerogel and orange biochar) were considered. The kinetics and isotherms of the pollutant adsorption were studied. The higher removal level was attained by the pellets with the adsorption process following a pseudo-2nd order model and being well defined by the Langmuir adsorption isotherm. After that, the pollutant was extracted from the pellets, concentrated in aqueous solution and treated by different advanced oxidation processes (anodic oxidation and electro-Fenton process). The results confirmed the higher efficiency of electro-Fenton treatment and its improvement was evaluated using a novel synthesized iron perlite catalyst. For this purpose, the synthesis of iron catalysts supported in perlite was performed by different methods (carbonisation, precipitation and hydrothermal). Among them, the hydrothermal synthesis produced catalysts with high catalytic activity, significant pollutant removal (>95 %), high stability and without iron leaching after several cycles of treatment. Based on these results, the development of a continuous treatment system was successfully carried out attaining high TOC removal values. Moreover, the feasibility of the treatment was also validated in complex water matrixes and toxicity assays demonstrated the viability of the proposed treatment for a global management of this pollutant.

In this study, adsorption of a non-steroidal anti-inflammatory drug such as Diclofenac (DCF) on a commercial carbonaceous aerogel honeycomb monolith (NANOLIT®-NQ40) was ascertained. Based on, the overall design of an adsorption treatment should include a feasible regeneration process for the spent adsorbent. In this work, the adsorption/desorption process was ameliorated by coupling of electrochemical technology (anodic/cathodic polarisation). It was determined that the anodic polarisation enhanced the DCF removal and it was related with the applied voltage and the disposition of the electrodes into the bulk solution. Anodic polarisation at optimal conditions (voltage 0.9 V, electrodes gap 2.5 cm and electrolyte concentration higher than 1 mM) provoked an enhancement (around 30%) in the DCF adsorption rate. The spent aerogel regeneration method for the adsorbed or electro-adsorbed DCF was investigated and cathodic polarisation proved to be a viable regeneration alternative attaining the total regeneration of aerogel. The electro-desorption mechanism seemed to be linked to the generation of repulsive intermolecular forces in the aerogel surface. Finally, the sequential electro-adsorption/electro-desorption process was performed in successive cycles. The results confirmed the feasibility of this strategy, maintaining the efficiency with no structural changes in the monolith after several cycles being the electro-reversible adsorption of pollutants on aerogel a promising technology for the removal of pharmaceuticals from wastewater. Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Agencia Estatal de Investigación | Ref. CTM 2017-87326-R

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG The removal of Diethyl hexyl phthalate (DEHP) and Dibutyl phthalate (DBP) is of great importance due to their potential adverse effects on the environment and human health. In this study, two bionanocomposites prepared by immobilization of Bacillus subtilis esterase by crosslinking to halloysite and supported in chitosan and alginate beads were studied and proposed as a green approach. The esterase immobilization was confirmed by physical–chemical characterization. Bionanocomposite using chitosan showed the best degradation levels in batch tests attaining complete degradation of DBP and around 90% of DEHP. To determine the operational stability and efficiency of the system, two fixed bed reactors filled with both bionanocomposites were carried out operating in continuous mode. Chitosan based bionanocomposite showed the best performance being able to completely remove DBP and more than 85% of DEHP at the different flowrates. These results proved the potential of these synthesized bionanocomposites to effectively remove Phthalic Acid Esters. Xunta de Galicia | Ref. ED431C 2021-43 Agencia Estatal de Investigación | Ref. PCI2022-132941

Overall, investigations about the utilization of electrokinetic technology alone or in combination with other processes have attracted particular attention in recent years for remediation of soils contaminated with heavy metals and organic compounds. This fact is due to its peculiar benefits together with its capability of operating in a fine and low-permeability matrix. This review aimed to ascertain the most recent developments on the commonly proposed integrated technologies (electrokinetic soil washing, electrokinetics coupled with permeable reactive barriers, electrokinetic-advanced oxidation processes, and bioelectrokinetic remediation), by evaluating the gaps, challenges, and trends of these systems in the last years. Special attention is paid to the current approaches for overcoming the main bottlenecks of electrokinetics concerning scale-up and reduction of electric energy consumption by integration of renewable energies. Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Agencia Estatal de Investigación | Ref. CTM2017-87326-R Xunta de Galicia | Ref. ED431C 2017/47

Currently, the interest in eco-friendly treatments for the removal of pollutants has increased and more sustainable treatment solutions are required. In this study, the homogeneous and heterogeneous activation of peroxymonosulfate (PMS) was carried out for the degradation of an industrial dye. Initially, the homogeneous PMS activation by different transition metals (Co, Cu, Ni, Fe) was ascertained. Cobalt resulted in the best performance attaining removal levels around 100% in only 30 min. Then, the influence of operational parameters such as pH and pollutant concentration were evaluated. The results displayed a high efficiency in the degradation and mineralisation operating close to neutral pH. The mechanism of the reaction was also studied and the obtained results demonstrated that sulfate radical is the primary reactive specie involved in the pollutant degradation. The optimisation of the degradation process was then carried out by a response surface methodology and several variables (PMS and Co concentration and temperature) were evaluated. The optimisation was performed in order to maximise the degradation and minimise the consumption of catalyst resulting in values of Co concentration 0.0125 mM, temperature 40 °C and PMS concentration 0.895 mM. Finally, heterogeneous activation by Co-catalyst immobilisation using alginate beads (Co-AB) and amberlite (Co-A) was performed. The results showed the superiority of Co-AB maintaining a high removal level after four treatment cycles with low Co leaching.

The aim of this study was to develop a comprehensive strategy for the degradation of a pharmaceutical compound, i.e., diclofenac (DCF), in which the solubility is strongly related to the solution pH. Therefore, in this study, alternative treatments according to DCF concentration ranges were developed. Working at the concentration of 7.5 mg/L and pH below 4, the considered treatments by sonolysis, anodic oxidation and electro-Fenton resulted in a good performance with high abatement levels. At high concentrations (140 mg/L), it was necessary to operate at near neutral pH, and the three proposed treatments (sonolysis, anodic oxidation and electro-Fenton using iron-alginate spheres as the heterogeneous catalyst) were performed. Heterogeneous electro-Fenton (HEF) resulted in the best option for the pollutant removal, and three new chitosan-based heterogeneous catalysts were synthesized and evaluated. The operational conditions (intensity and dosage of catalyst) were optimized resulting in an intensity of 300 mA and catalyst dose of 20 g/L. Operating at these conditions, high levels of DCF degradation and mineralization were achieved. Several treatment cycles, using the same catalyst, were successfully carried out, and the catalysts demonstrated good stability and the potential to operate in a continuous way. Finally, the evolution of carboxylic acids and intermediate generation were analysed leading to the proposal of a plausible DCF degradation pathway for HEF.

This study proposed an integrated valorisation system, by combining adsorption and electro-Fenton processes for fast and effective micropollutant remediation of a complex pharmaceutical mixture. The pharmaceuticals venlafaxine, fluoxetine and trazodone, commonly detected in the environment (river water and sediment), were selected in this study as target pollutants. Initially, the electro-Fenton degradation process of the ternary mixture was optimised. For this, a Box-Behnken experimental design was used and the degradation of each pollutant, as a response function, was evaluated using three key operational process parameters (iron concentration, current intensity and solution pH). The pharmaceutical mixture was removed by total adsorption onto the biochar, the regeneration of which was then carried out under the optimal electro-Fenton conditions (0.24 mA, 0.33 mM Fe2+ and pH 3.2). In addition, different options in relation to the presence of iron were considered: i) iron dissolved in aqueous solution; ii) iron supported on the biochar; iii) no addition of iron (“self-cleaning”). The results confirmed that the natural content of iron in the biochar was enough to catalyse the electro-Fenton regeneration. The adsorption-electro-Fenton regeneration process was repeated over several cycles with no reduction in the efficiency of either process. Finally, this combination (adsorption and electro-Fenton process) was tested using an aqueous matrix from a wastewater treatment plant., This research has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and ERDF Funds (Grant N°CTM2017-87326-R) and ERA-NET Cofund WaterWorks2015 Call (funded by the EU and FCT/UEFISCDI/FORMAS) for financial support through the REWATER International Research project. This work was also supported by UIDB/50006/2020 and UIDP/50006/2020 by the Fundação para a Ciência e a Tecnologia (FCT Portugal)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES Portugal) through national funds. Manuela M. Moreira (project CEECIND/02702/2017) also acknowledge for her financial support financed by national funds through FCT and to REQUIMTE/LAQV. The authors are also grateful to ERASMUS+ program by founding the research stay of Anton Puga. The invitation by the E3TECH Spanish Network of Excellence (CTQ2017-90659-REDT (MEIC/AEI)) is kindly acknowledged.

Hydrothermal carbonization (HTC) is a facile, low-cost and eco-friendly thermal conversion process that has recently gained attention with a growing number of publications (lower 50 in 2000 to over 1500 in 2020). Despite being a promising technology, problems such as operational barriers, complex reaction mechanisms and scaling have to be solved to make it a commercial technology. To bridge this current gap, this review elaborates on the chemistry of the conversion of lignocellulosic biomass. Besides, a comprehensive overview of the influence of the HTC operational conditions (pH, temperature, water:biomass ratio, residence time and water recirculation) are discussed to better understand how hydrochar with desired properties can be efficiently produced. Large-scale examples of the application of HTC are also presented. Current applications of hydrochar in the fields of energy, biocatalysis and environment are reviewed. Finally, economic cost and future prospects are analyzed.

In this age, a key target for enhancing the competitiveness of the chemical, environmental and biotechnology industries is to manufacture high-value products more efficiently and especially with significantly reduced environmental impact. Under this premise, the conversion of biomass waste to a high-value added product, biochar, is an interesting approach under the circular economy principles. Thus, the improvements in the biochar production and its new and innovative uses are hot points of interest, which are the focus of vast efforts of the scientific community. Biochar has been recognized as a material of great potential, and its use as an adsorbent is becoming a reliable strategy for the removal of pollutants of different streams, according to its high adsorption capacity and potential to eliminate recalcitrant compounds. In this review, a succinct overview of current actions developed to improve the adsorption capability of biochar, mainly of heavy metal and organic pollutants (dyes, pharmaceuticals and personal care products), is summarized and discussed, and the principal adsorption mechanisms are described. The feedstock and the production procedure are revealed as key factors that provide the appropriate physicochemical characteristics for the good performance of biochar as an adsorbent. In addition, the modification of the biochar by the different described approaches proved their feasibility and became a good strategy for the design of selective adsorbents. In the last part of this review, the novel prospects in the regeneration of the biochar are presented in order to achieve a clean technology for alleviating the water pollution challenge. Xunta de Galicia | Ref. ED431C 2017/47 Ministerio de Ciencia, Innovación y Universidades | Ref. CTM2017-87326-R

In this work, an eco-friendly solution for the remediation of wastewater generated in the lignin recovery process from eco-industrial paper mill has been proposed in their way towards a more circular economy strategy. Thus, the application of the electro-Fenton process for the degradation of the non-recovered lignin and other organic compounds form a scarcely studied acid black liquor waste (ABLW) was successfully performed. This treatment was able to operate in a range of COD loads (0.5–19.5 mg O2·L–1) showing high degradation values of the ABLW determined by the abatement of color, total phenolic content and COD. Then, the optimization of the working conditions for the design of a sustainable treatment system with optimum efficiency was carried out using a response surface methodology. The experiment carried out in the calculated optimal conditions for the electro-Fenton degradation process (current intensity 132.5 mA, catalyst dosage of 0.10 mM, and temperature 40 °C) showed a COD removal of 74.82% and current efficiency 77.79%, close to the theoretical value predicted by the model 73.12% and 77.06%, respectively. In addition, the identification of the final products permitted to confirm the mineralization efficiency.

In this study, the degradation of the ionic liquid (IL) 1,3-dicyclohexylbenzimidazolium chloride ([DCy6bim][Cl]) was carried out by applying an heterogeneous electro-Fenton (HEF) treatment using iron alginate spheres (FeAS) as catalyst. Initial trials were performed at current between 50 and 250 mA, different FeAS dosages (1–5 g), and [DCy6bim][Cl] concentrations (70–280 mg L−1) as key parameters for the characterization of the HEF process. Comparative experiments suggest that high current, low FeAS dosage and low [DCy6bim][Cl] concentration are the best conditions to yield near complete total organic carbon decay after 4 h. In order to evaluate the catalyst behaviour and iron leaching during the degradation of [DCy6bim][Cl], differential pulse voltammetry (DPV), a sensitive and selective electroanalytical technique, was used to monitor the IL degradation, by-products and iron evolution into the solution at high concentration levels. The profile of the voltammetric curves obtained by DPV suggests almost complete cleavage of the cation structure of [DCy6bim][Cl] during the first 120 min. At longer treatment times, DPV revealed the generation of iron complex with chloride and carboxylic acids. Finally, chromatographic analysis of these carboxylic acids and inorganic anions permitted to validate the results obtained by DPV and demonstrated the feasibility of the HEF process for IL degradation. Graphical Abstract: [Figure not available: see fulltext.] Ministerio de Economía y Competitividad (España) | Ref. CTM2014-52471-R Ministerio de Educación, Cultura y Deporte (España) | Ref. FPU16/02644 Xunta de Galicia | Ref. ED431C 2017/47 Xunta de Galicia | Ref. ReGaLIs ED431 2017/11 Xunta de Galicia | Ref. BIOAUGA ED431 2017/06

Personal care products are known as endocrine-disrupting compounds and their degradation is a matter of concern to avoid their release into the environment. For this reason, the main objective of this study is to develop an effective advanced oxidation process able to degrade a paraben as methyl paraben (MePa). Initially, the efficiency of two electrodes, Graphite felt (GF) and Ruthenium (Ru), was compared on the degradation of MePa by anodic oxidation (AO) and electro-Fenton (EF). Near complete degradation was obtained after 1 h when Graphite felt (GF) was used as cathode in EF, showing the superiority of this treatment over AO. To improve this process, heterogeneous EF through inclusion of iron into the cathode was carried out. To do that, four iron-carbonaceous cathodes were prepared based on GF (raw or activated with H 2 SO 4 , named AGF-1) showing a significant iron content (25–30%) and attaining high degradation values (95–100%) in all of them. From preliminary experiments was determined that by the use of AGF-1 as cathode the electrode performance improved, reducing significantly the treatment time required and the total amount of MePa contained in the solution had disappeared after 30 min with a TOC reduction of 98.68% after 120 min. The profiles of MePa exhibit an exponential decay throughout time being satisfactorily described by pseudo-first order reaction kinetic showing a maximum degradation rate of around 0.143 min −1 at optimal conditions (100 mA and pH 3). In addition, the selected cathode showed high structural and catalytic stability after several reuses. Finally, key steps of a plausible degradation pathway were tailored in accordance with identified and quantified intermediate products of the degradation process.

In this study, the degradation of pyrimethanil, a pesticide considered as a model pollutant, by electro-Fenton process was optimized. Thus, three different carbonaceous cathode configurations were selected: taffeta carbon fiber (TCF), unidirectional carbon fiber (UCF), and graphite felt (GF). Initially, the H2O2 production ability of these cathodes was evaluated showing results that varied from around 27 to 12 mg/L for UCF and TCF, respectively. These results are in accordance with the cyclic voltammetry study and the hydrophilic behavior of the different cathodes. The degradation of pyrimethanil by anodic oxidation shows to be significantly less efficient than electro-Fenton treatments with any cathode. However, the best results were obtained when UCF was used, achieving the total removal after 45 min. Working with the best cathode, an estimation of the treatment cost was performed based on the electric consumption and mineralization efficiency of the system working at different intensity values. After 120 min, total degradation of the selected pollutant and total organic carbon reduction between 25 and 45% were achieved. Furthermore, different intermediates generated during the degradation process were identified and suitable degradation pathway was proposed. Finally, a continuous treatment system was evaluated at different flow rates and modeled, showing a good agreement between the theoretical and the experimental data.

Nowadays, the majority of the remediation studies have been carried out using artificially spiked soils with individual target pollutants. One of the bottlenecks is the application of developed technologies to the removal of pollutants in real aged contaminated soils, which is much more difficult than in spiked ones. Thus, in this study, the performance of a combined technology as flushing using different oxidants coupled with the electrokinetic technique was performed and its feasibility was evaluated to remediate a real industrial polluted soil with low permeability in which is not possible the conventional flushing system. Initially, the characterization of this soil showed a wide distribution of hydrocarbons with a total petroleum hydrocarbons content of 29,666 mg·kg − 1 . Based on the hydrocarbons distribution, the source of the pollutants was identified as a spillage of motor oil and diesel. Moreover, the aging of the pollution was evaluated (around 16 years) resulting in a historically polluted soil. Initially, an ex-situ oxidative treatment was considered. This treatment demonstrated the feasibility of the different oxidants on the removal of the hydrocarbons, achieving removal values higher than 65% in all the experiments. Furthermore, a critical parameter in the treatment, as pH, was also evaluated resulting in an acidic environment for KMnO 4 and Na 2 S 2 O 8 and basic environment for NaOCl. Later, the simulated bench scale in situ removal of the contaminants was considered, but the delivery of the oxidants into the polluted soil is hard, and for this reason, the coupling of flushing and electrokinetics was carried out. Working at the optimal conditions determined before, the treatment with the selected oxidants was performed. The total petroleum hydrocarbons (TPH) removal (40–60%), the profile of hydrocarbons and metals in the different sections of the soil after the treatments proved the efficiency of the system. The viability of the selected hybrid technique in the removal of TPH from historically polluted soils was demonstrated.

Electro-Fenton technology was able to decrease zebrafish embryotoxicity of fluoxetine and pirimicarb, when single or in mixture.

Electro-Fenton generation of ·OH is more efficient and significant than the ·OH produced in the anode surface by anodic oxidation. Electro-Fenton process was optimised determining the relationship among key variables as electrodes surface and stirring rate. At optimal conditions, the combination of fluoxetine and pirimicarb was easily degraded with high mineralisation level.

The search for efficient and environmentally friendly adsorbents has positioned lignocellulosic materials as attractive and low-cost alternatives instead of synthetic materials. Consequently, the present work investigates the efficacy of untreated lime peel (LM) and pineapple core (PP) as biosorbents for Cr(VI) removal. The maximum adsorption capacities (acquired at 24 h) of these sorbents were 9.20 and 4.99 mg/g, respectively. The use of these sorbents is expected to offer a rapid and efficient solution to treat effluents containing Cr(VI). Pineapple core showed the best biosorption properties and good distribution coefficients (distribution coefficient KD 8.35&ndash, 99.20 mL/g) and the optimization of the adsorption was carried out by a response surface methodology using the Box&ndash, Behnken design. Thus, the effect of pH, biosorbent dosage, and temperature were assessed during the whole procedure. Three different responses were studied&mdash, Cr(VI) removal, Cr biosorption, and distribution coefficient&mdash, and the optimal conditions for maximizing the responses were identified by numerical optimization applying the desirability function. The resulting optimal conditions were: initial solution pH 2.01, biosorbent dosage 30 g/L, and temperature 30.05 &deg, C. Finally, the process scale-up was evaluated by the simulation of the process working with a column of 100 L using the Fixed-bed Adsorption Simulation Tool (FASTv2.1). This research presents the obtained environmental benefits: i) reduction of pineapple waste, ii) Cr(VI) reduction and biosorption, iii) shortest sorption time for Cr, iv) properties that allow the biosorption process on the flow system, and v) low-cost process.

Hoy en día, se requiere el uso de herramientas efectivas que refuercen el aprendizaje de los estudiantes. Un ejemplo claro es el uso de Aprendizaje basado en el desarrollo de un proyecto a escala real (ABDPER). ABDPER implica un estudio en profundidad de una situación particular y la utilización de los conceptos adquiridos durante el año académico. La principal ventaja de la enseñanza con ABDPER es que los estudiantes participan activamente en la comprensión de los principios al abstraerse de la teoría enseñada a través del razonamiento inductivo. En nuestro caso, ABDPER se ha aplicado a diversas materias, si bien en este trabajo se expondrá los resultados obtenidos en la materia Reactores y Biotecnología. Para esta propuesta, los estudiantes aplican el conocimiento gradual adquirido durante el semestre al diseño y escalado de una planta de producción industrial e implementarán en el desarrollo del mismo los avances de I+D y las Mejores Tecnologías Disponibles (MTD). La respuesta de los estudiantes ha sido muy positiva a esta nueva metodología y se puede concluir que el uso de esta tecnología basada en artículos de investigación científica aumentó las habilidades de los estudiantes en el marco de la asignatura.

In the last decades, a wide range of organic pollutants has been identified as emerging pollutants in the aquatic environment. However, limited work has been done examining the ability of microorganisms to degrade emerging pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and pesticides. In this work, a novel PAH and pesticide degrading bacterium was isolated from polluted marine sediment. After morphological and genetic characterization, the novel strain showed the highest similarity to Bacillus thuringiensis . The ability of the isolated bacterium to degrade the target pollutants was evaluated in shake flasks and bioreactor assays, reaching high levels of degradation for the model pollutants studied, phenanthrene and imidacloprid. Furthermore, the plausible degradation pathways of both pollutants were established. Based on the reported results, it can be concluded that B. thuringiensis has an enormous potential to mineralize a wide spectrum of emerging pollutants, such as PAHs and pesticides.

The treatment of winery wastewater is necessary since it constitutes an environmental problem due to its high organic content and chemical oxygen demand and its low pH. However, these characteristics hinder the use of conventional technologies commonly utilized for the treatment of effluents. Therefore, new technologies for the management of this type of wastewater are required. In this sense, the photo electro Fenton process (PEF) was proposed as a good alternative because of the synergetic effect among Fenton, electrolysis and photolysis processes. In this study, the development of a new double chamber cubic reactor for the treatment of winery wastewater using PEF was performed. Surface response methodology was applied based on Box–Behnken design to define the best operational conditions. The selected key variables were voltage, distance between electrodes and the organic load of the effluent. Among the parameters optimized, distance between electrodes and voltage were identified as significant in the model. Under the optimized conditions the treatment of real winery wastewater was efficiently carried out. Finally, it can be concluded that the configuration of this reactor is suitable for the remediation of this type of effluents.

In this study, the application of hydrocolloid and fiber industry wastes and their transformation in biochar and biocomposite as biosorbents for emerging pollutants effective removal was carried out. Initially, the adsorption ability of six different wastes was ascertained in single and competitive removal of sulfamethoxazole (SMX) and methylparaben (MePa). Among them, fiber extraction process wastes presented the best result attaining maximum uptakes with removal levels up to 23 and 48% of MePa and SMX, respectively. The adsorption capacity was enhanced by fiber waste biochar preparation at 500 °C and 30 min under nitrogen atmosphere, and improved by the preparation of laccase-biocomposites, achieving maximum uptakes more than ten-fold the obtained using raw material. The simultaneous removal of the pollutants by the biocomposite followed a pseudo-second order kinetic and resulted in maximum uptakes of 24.06 and 23.15 mg/g for SMX and MePa, respectively. Finally, raw material and laccase-biocomposite behaviours were simulated by homogeneous surface diffusion model. Previously, the isotherms were studied fitting well to Freundlich model. The obtained results remarked the feasibility of laccase-biocomposite in which reactive groups incorporation on the biochar surface could be responsible for facilitating the pollutants removal from the aquatic environment.

The requirement of feasible adsorption-regeneration systems in the treatment of emerging pollutants such as pharmaceuticals is a social demand. In this work, the treatment of a mixture with sulfamethoxazole (SMX) and methyl paraben (MP) was performed by the preparation of biochar derived from the lime fiber waste at different conditions (320–500 °C and residence time 5–30 min). Based on the adsorption efficiency (maximum uptake of MP 54.25 mg/g and SMX 64.04 mg/g) and energy expenditure, the biochar obtained at 320 °C with a residence time of 30 min was selected as the best material. Subsequently, a deep study of this biochar adsorption process demonstrated that pseudo-second order model fitted well the adsorption kinetics of both pollutants and the Freundlich isotherm model describes the binary system equilibrium. After that, the regeneration of the adsorbent was carried out by advanced oxidation processes. Initially, Fenton process was considered and the regeneration of the adsorbent was performed in homogeneous and heterogeneous systems. The necessity of continuous addition of H2O2 led to the evaluation of other alternatives (electro-oxidation-H2O2 or electro-Fenton). The optimisation of the conditions was performed in liquid phase and operational parameters such as cathode electrode (carbon black modified electrodes), H2O2 production, intensity, pH and degradation kinetics were studied. Among them, the electro-Fenton process demonstrated to be quite successful in the removal of the pollutants and it was applied in successive cycles of adsorption-regeneration.

In this study, the performance of three commercial available monolithic carbonaceous aerogels (NQ30A, NQ60A and NQ80A) for the removal of different emerging pollutants, detected in water sources, was evaluated. More specifically, the removal of two pharmaceuticals (antipyrine and sulfamethoxazole) and an anti-fungal agent (methyl paraben), widely used in cosmetics, was studied. The NQ60A demonstrated the best adsorption characteristics and effectively adsorbed over 50 mg/g of the antipyrine and around 30 mg/g sulfamethoxazole and methyl paraben. The kinetic study of the adsorption process revealed that pseudo-first order kinetic model described very well the kinetic behaviour of the selected pollutants onto the NQ60A aerogel. After that, the regeneration of the loaded aerogel, with antipyrine alone and in presence of the other two contaminants, was evaluated. The regeneration was accomplished in two ways: (1) by using directly the loaded aerogels as cathode during the electro-Fenton treatment and (2) by its regeneration immersed in the bulk volume of electro-Fenton cell (boron doped diamond as anode and carbon felt as cathode). Both approaches can provide an effective removal of the pollutants inside the aerogel. In addition, the regenerated aerogel proved to maintain its adsorptive properties and can be successfully reused in successive cycles of adsorption-regeneration. On the basis of these promising results, it can be concluded that the proposed strategy based on aerogels adsorption and electro-Fenton regeneration is a suitable alternative for emerging pollutants removal from water streams.

Nowadays, the vast majority of pollutants are found at low concentrations in water bodies and their treatment requires efficient and cost-effective strategies. This research proposes the application of two complementary treatments (physical and oxidative) for the removal of the ionic liquid 1-butyl, 2,3-dimethylimidazolium chloride ([bdmim]Cl) from aqueous medium. Initially, a quick adsorption process was set up. For that, a natural silicate, attapulgite, was used as adsorbent and an uptake of 7.3 mg g−1 was attained. Once the viability of the adsorbent was proved, a continuous adsorption treatment, using a column, was carried out and the behaviour of the proposed system was studied using theoretical and experimental breakthrough models. Afterwards, the regeneration of the adsorbent was evaluated with different desorbing agents reaching the best results with a mixture 20/80 H2O/ACN with 0.04 M NH4Cl. Five adsorption-desorption cycles were done using the attapulgite as adsorbent without any detriment on the process performance, opening a path for future applications. After the desorption of the pollutant and the ACN recuperation, an extremely concentrated aqueous solution of the pollutant was attained (618 mg L−1 of [bdmin]Cl and 0.2 M NH4Cl) and treated by electro-Fenton process. NH4Cl showed a high detrimental effect on the electro-Fenton (EF) process and thus, it was removed. Then, the new solution was efficiently treated by EF with a low energy consumption (0.05 kWh g TOC−1) and high mineralization levels (70%) after 8 h of treatment.

Over the last decades, advanced oxidation processes have often been used alone, or combined with other techniques, for remediation of ground and surface water pollutants. The application of heterogeneous catalysis to electrochemical advanced oxidation processes is especially useful due to its efficiency and environmental safety. Among those processes, electro-Fenton stands out as the one in which heterogeneous catalysis has been broadly applied. Thus, this review has introduced an up-to-date collation of the current knowledge of the heterogeneous electro-Fenton process, highlighting recent advances in the use of different catalysts such as iron minerals (pyrite, magnetite or goethite), prepared catalysts by the load of metals in inorganic and organic materials, nanoparticles, and the inclusion of catalysts on the cathode. The effects of physical-chemical parameters as well as the mechanisms involved are critically assessed. Finally, although the utilization of this process to remediation of wastewater overwhelmingly outnumber other utilities, several applications have been described in the context of regeneration of adsorbent or the remediation of soils as clear examples of the feasibility of the electro-Fenton process to solve different environmental problems. Xunta de Galicia | Ref. ED431C 2017/47 Ministerio de Economía y Competitividad (España) | Ref. CTM2014-52471-R

The current need for effective regeneration processes to be used in valorization of spent adsorbent demands the research of novel alternative techniques such as application of Advances Oxidation Processes. In this sense, the recent application of electroradical (ER) processes turned out to be very promising in terms of the drugs degradation from different environments. Thus, in this study, harnessing of a low cost natural adsorbent, Tunisian bentonite (BE), was evaluated for the removal of a model drug such as methylthioninium chloride (MC), and then its regeneration by ER processes was demonstrated. Initially, the BE was characterized and the adsorption of the MC was studied. This process followed a pseudo-first order kinetic and Langmuir isotherm fitted well to data reaching uptake values around 145–155 mg g−1. After that, BE regeneration by an ER process such as electro-Fenton process was ascertained. Due to the high buffering capacity of the BE, the addition of citric acid (1 mM) was necessary in order to assure the acidic medium to favor the oxidation reaction. By operating under optimized experimental conditions (current intensity 300 mA, pH 3, Fe2+ (1 mM) and citric acid (1 mM)) near complete adsorbent regeneration was achieved after 300 min of treatment and the pseudo-first-order model fitted well the degradation data. Furthermore, the adsorbent was efficiently used in successive cycles of adsorption-regeneration without operational problems that proved the efficiency of this technology. From the obtained results, a side-by-side configuration was designed and simulated, confirming the viability of the design at large scale.

Conventional water treatments are generally inadequate for degradation of emerging pollutants such as ionic liquids (ILs). The use of heterogeneous electro-Fenton (HEF) has attracted great interest, due to its ability to efficiently oxidize a wide range of organic pollutants operating in cycles or in continuous mode. In this study, the removal of a complex IL from the imidazolinium family (1,3-Bis(2,4,6-trimethylphenyl)imidazolinium chloride), by means of HEF using iron alginate spheres as catalyst has been investigated, resulting in significant TOC decay after 6 h. The optimization of the key process parameters (current, IL concentration and catalyst dosage) has been performed using a Box-Behnken experimental design and achieving 76.98% of TOC abatement in 2 h of treatment. Current proved to be a crucial parameter and high catalyst dosage is required to achieve the maximum removal. In addition, an insight about the availability of iron into the reactor and the evolution of several intermediates has been carried out by employing differential pulse voltammetry on screen-printed carbon electrodes. The evolution of the different voltammetric peaks confirmed the influence of iron release, and the generation of several iron complexes has permitted the comprehension of the degradation pathway, which has been validated by chromatographic techniques. Ministerio de Economía y Competitividad (España) | Ref. CTM2014-52471-R

The consumer society is demanding products with a 100% natural label, therefore the industry is concerned about finding a productive process that provides these items. Under this premise, the use of solid-state fermentation (SSF) to obtain natural compounds instead of a chemical productive process is a reliable alternative. This chapter shows the potential application of SSF for the production of food, brewed foods, and several metabolites of great interest to the food industry, including enzymes, preservatives, flavoring and coloring agents, beverages, and food condiments. A complete revision from the well-known processes implemented at industrial scale such as beverage production, until new processes that are in their infancy are presented and described. The use of new microorganisms (isolated or recombinant) with high yields, valorization of residues as substrates, optimization operational parameters, or hybrid fermentation procedures are presented as interesting approaches for enhancing SSF in order to establish it as a competitive process for food industry application. Finally, this chapter also highlights that the necessity of research in order to carry out the scale-up of most described SSF processes is latent.

Nowadays, a wide variety of pollutants are discharged to different water sources and become water contaminants. To overcome this problem, bioremediation has been studied as an alternative for their treatment due to its low cost, high efficiency and environmentally friendliness. However, it is necessary to search for microorganisms able to remediate pollutants of different nature. In this work, the isolation and identification of remediating-bacteria from polluted marine coastal sediment were carried out. The isolation assays were carried out using phenanthrene as the only carbon source. The identification of the strains was performed by PCR amplification of 16S rDNA. It was resolved in one band and the sequencing showed that this band was derived from Serratia plymuthica. The removal ability of this microorganism was assayed with phenanthrene, benzo[a]pyrene, different insecticides and Cr(VI). The isolated bacterium showed high removal ability of imidacloprid, methomyl, fenamiphos, and Cr(VI). After that, bioreactor scale-up (5 L) was studied with a mixture of these pollutants. Total removal degrees were obtained for organic compounds and around 96% of Cr(VI) removal was reached. Furthermore, the removal rate of the different pollutants fitted well to a logistic model. The present study states that the identified bacterium can play a vital role in bioremediation of an aquatic environment polluted with mixtures of contaminants.

The regeneration and reuse of adsorbents is a subject of interest nowadays in order to reduce the pollution and the wastes generated in the adsorption wastewater treatment. In this work, the regeneration of the spent kaolinite by different advanced oxidation processes (Fenton, electro-Fenton and electrokinetic-Fenton) was evaluated. Initially, it was confirmed the ability of a low cost clayey material, kaolinite, for the adsorption of model dye such as Rhodamine B showing Freundlich isotherm fitting. Then, the regeneration and consequent degradation of the pollutant in the adsorbent by Fenton based processes was carried out. The role of different parameters affecting the regeneration process (H2O2:Fe2+ ratio, liquid:solid ratio) were evaluated. Working at 100:1 H2O2:Fe2+ ratio and 30min near complete dye removal (around 97%) from kaolinite was obtained by Fenton treatment. After that, a two-stage treatment for adsorption-regeneration was evaluated during five treatment cycles demonstrating its viability for regeneration of the adsorbent through dye degradation. Based on the successful application of Fenton technique, the improvement of the treatment by electro-Fenton and electrokinetic-Fenton were studied for different solid:liquid ratios achieving satisfactory regeneration values.

Over the past few years, the increasing amount of pollutants and their diversity demand to develop versatile low-cost adsorption systems. The use of biomass feedstock such as agricultural residues, wood chips, manure or municipal solid wastes as source to produce low-cost biosorbent, and the new advances in their synthesis have encouraged remarkable efforts towards the development of biochar “on demand” in which their characteristics can be improved. This new trend opens the potential of biochar application in the removal of pollutants from wastewater, however, its use in environmental management requires the development of full-scale biosorption in engineered systems. Thus, this paper provides a brief review of recent progress in the research and practical application of biochar with a special emphasis on its potential to reduce the pollutants present in wastewater or to render them harmless. Furthermore, research gaps and uncertainties detected in their scale-up in continuous-flow systems are highlighted.

The chemical process scale-up, from lab studies to industrial production, is challenging and requires deep knowledge of the kinetic model and the reactions that take place in the system. This knowledge is also useful in order to be employed for the reactor design and the determination of the optimal operational conditions. In this study, a model substituted phenol such as p -nitrophenol was degraded by electro-Fenton process and the reaction products yielded along the treatment were recorded. The kinetic model was developed using Matlab software and was based on main reactions that occurred until total mineralization which allowed predicting the degradation pathway under this advanced oxidation process. The predicted concentration profiles of p -nitrophenol, their intermediates and by-products in electro-Fenton process were validated with experimental assays and the results were consistent. Finally, based on the developed kinetic model the degradation process was optimized using central composite design taking as key parameters the ferrous ion concentration and current density.

Contamination of aqueous environments by hazardous chemical compounds is the direct cause of the decline of safe clean water supply throughout the globe. The use of unconventional water sources such as treated wastewater will be a new norm. Emerging nanotechnological innovations have great potential for wastewater remediation processes. Applications that use smart nanomaterials of inorganic and organic origin improve treatment efficiency and lower energy requirements. This book describes the synthesis, fabrication, and application of advanced nanomaterials in water treatment processes; their adsorption, transformation into low toxic forms, or degradation phenomena, and the adsorption and separation of hazardous dyes, organic pollutants, heavy metals and metalloids from aqueous solutions. It explains the use of different categories of nanomaterials for various pollutants and enhances understanding of nanotechnology-based water remediation to make it less toxic and reusable.

The objective of this study was to find a suitable and versatile agroforestry waste as alternative low-cost biosorbents for the removal of inorganic and organic compounds present in the wastewater of tannery industry [leather dyes and Cr(VI)]. Grapefruit peelings, fern, eucalyptus barks, oak leaves and cane pruning of grapevines were evaluated as biosorbents. Among them, grapefruit peelings showed the best results reaching 45 and 55% for the mixture of dyes and Cr(VI), respectively. A significant improvement in the performance of this biosorbent was obtained when it was pretreated with H2O2 (1M) attaining the highest removal capacity of 80% and 100%, respectively. This biosorbent was characterised showing an adsorption capacity of 1.1003meq/g and pHZPC 3.48. The adsorption working parameters, kinetics and isotherms were deeply studied in order to scale up the process to a continuous treatment system. Adsorption isotherms data fitted well to the Langmuir model with a maximum uptake of 37.427mg/g for dyes mixture and 39.0628mg/g for Cr(VI). Finally, the dynamic behaviour of the system, operating at different flow rates, was evaluated using a Homogeneous Surface Diffusion Model. Pretreated grapefruit peelings demonstrated to be a suitable low-cost biosorbent in the treatment of wastewater of tannery industry., This work has been funded by the Spanish Ministry of Economy and Competitiveness, Xunta de Galicia and ERDF Funds (Projects CTM 2011-25389 and GRC 2013/003). The authors are grateful to Xunta de Galicia for financial support of the researcher Emilio Rosales under a postdoctoral grant and the Spanish Ministry of Economy and Competitiveness for financial support of the researcher Marta Pazos under a Ramón y Cajal grant.

The feasibility of the electrokinetic-Fenton technology coupled with surfactants in the treatment of real historically hydrocarbons polluted soils has been studied. The characterisation of these soils from Spain and Romania was performed and identified as diesel and diesel-motor oil spillages, respectively. Moreover, the ageing of the spillages produced by the soil contamination was estimated showing the historical pollution of the sites (around 11 and 20 years for Romanian and Spanish soils, respectively). An ex-situ electrochemical treatment was performed to evaluate the adequacy of surfactants for the degradation of the hydrocarbons present in the soils. It was found an enhancement in the solubilisation and removal of TPHs with percentages increasing from 25.7 to 81.8% by the presence of Tween 80 for Spanish soil and from 15.1% to 71.6% for Triton X100 in Romanian soil. Therefore, the viability of coupling enhanced electrokinetic and Fenton remediation was evaluated through a simulated in-situ treatment at laboratory scale. The results demonstrated that the addition of the selected surfactants improved the solubilisation of the hydrocarbons and influenced the electroosmotic flow with a slight decrease. The efficiency of the treatment increased for both considered soil samples and a significant degradation level of the hydrocarbons compounds was observed. Buffering of pH coupled with the addition of a complexing agent showed to be important in the treatment process, facilitating the conditions for the degradation reactions that take place into the soil matrix. The results demonstrated the effectiveness of the selected techniques for remediation of the investigated soils.