J. Sánchez-Martín

Novel tannin-based adsorbent in removing cationic dye (Methylene Blue) from aqueous solution. Kinetics and equilibrium studies.

Natural tannin-based adsorbent has been prepared on the basis of the gelification of Quebracho bark extract. The resulting product, Quebracho Tannin Gel (QTG) was tested as cationic dye adsorbent with Methylene Blue (MB). Kinetics of adsorption process were studied out and a period of 15 days was determined for reaching equilibrium. The influences of pH and temperature were evaluated. As pH or temperature raise q capacity of QTG increases. Theoretical modelization of dye-QTG adsorption was carried out by multiparametric adjustment according to Langmuirs hypothesis. Values of the k(l1), k(l2) and activation energies were calculated.

Optimization of the synthesis of a new coagulant from a tannin extract

The current article studies the optimization of a new coagulant agent for water purification and wastewater remediation. Design of experiments is used for optimizing the production of this new tannin-based coagulant by using Acacia mearnsii de Wild tannin extract, NH(4)Cl and formaldehyde. The effectiveness of this product was confirmed on dye-polluted wastewater and surfactant wastewater. This cationic coagulant seems to be sensitive to temperature and tannin-NH(4)Cl ratio (g of ammonium chloride per g of tannin extract). NH(4)Cl ratio was found to be more influent than temperature and no interaction is presented between these two parameters. For each system, an optimum combination NH(4)Cl ratio and temperature was found: 24.9°C and 2 g g(-1) for dye removal and 36.4°C and 1.87 g g(-1) for surfactant elimination. The optimal conditions were merged to produce a combined coagulant that was tested on dye, surfactant, surface river water and municipal wastewater. Predicted levels of remediation were experimentally confirmed.

Advanced Photochemical Degradation of Emerging Pollutants: Methylparaben

This paper addresses the oxidation by ultraviolet radiation of methylparaben, a ubiquitous and suspicious preservative which is massively added to cosmetics and personal care products. Experiments included pH and temperature variation, as well as several experimental conditions such as presence/absence of hydrogen peroxide, titanium dioxide, or some different water matrix (surface water or ground water). Results were evaluated under the line source spherical emission model, so quantum yield was the adequate target variable for explaining the process. A modified Arrhenius correlation including pH level was used for modelling the whole system.

Treatment of high strength olive mill wastewater by Fenton's reagent and aerobic biological process

The present work describes the application of a Fentons reagent pretreatment combined with an aerobic biological process to remove the olive mill wastewater (OMW) pollutant load. Wastewater treatment was monitored by means of global parameters directly related to the concentration of organic compounds in OMW effluents: chemical oxygen demand (COD) and total phenolic content (TP). The biologic treatment itself allowed conversions from 67 to 83% of COD and 55 to 61% of TP. In the Fentons reagent process a fixed H2O2/COD ratio of 0.20, a pH = 3.5 and a H2O2/Fe2+ molar ratio of 15 were defined as optimal conditions to treat the OMW. For an initial COD load of 92.5 g/L−1) the Fenton reagent-biologic combined process allowed a global removal of 80.7% COD and 93.7% TP. A kinetic study was performed resorting to the Grau model. The application of this model allowed observing an increase in the kinetic constant of the combined process (kFB = 24.7 g/L−1 day) when compared to the single aerobic process (kB = 19.4 g/L−1 day).

Multiparameter Quantitative Optimization in the Synthesis of a Novel Coagulant Derived from Tannin Extracts for Water Treatment

A novel tannin-based coagulant has been synthesized at lab scale. A multiparameter optimization was performed on the production process, and up to five variables were studied according to the response surface methodology in a face-centered design of experiments which included two temperatures, two pH levels, and the reaction time in the chemical process. The coagulant involved diethanolamine, formaldehyde, and a tannin extract from Acacia mearnsii de Wild. The results revealed an average optimum combination for dye and surfactant removal which was able to remove either Alizarin Violet 3R and sodium dodecylbenzene sulfonate efficiently from water effluents.

Feasibility of electrochemical degradation of pharmaceutical pollutants in different aqueous matrices: Optimization through design of experiments

Electrochemical degradation of different effluents polluted with carbamazepine, a well-known refractory pharmaceutical contaminant, was addressed in this article. Ultrapure water (Milli-QTM technology), surface water from a lake and urban wastewater were the matrices used to evaluate the feasibility of performing the electro-oxidation of carbamazepine. Specific designs of experiments were planned for each of the aqueous media. The initial carbamazepine concentration and the electric current density were considered as the operational variables. Although the optimal values of both variables follow the same trend in the three cases, significant differences are observed regarding the comparative influence of each variable on the degradation of carbamazepine.

Opportunities Given by Final Degree Dissertations inside the EHEA to Enhance Ethical Learning in Technical Education.

Final degree dissertations in cooperation and development (FDDCD) can be a suitable tool for raising the awareness of the university community. In this paper the paradigmatic actions made in this frame in the University of Extremadura for the last five years have been analysed with the aim of elucidating the possible ways to improve the teaching–learning process. For this target, FDDCDs have to be included in a learning project that is designed according to the needs and circumstances of each student. In this way, both the ethics and technical knowledge of future professionals are enhanced.

What do K-12 students feel when dealing with technology and engineering issues? Gardner's multiple intelligence theory implications in technology lessons for motivating engineering vocations at Spanish Secondary School

ABSTRACT The interest on engineering and scientific studies can be raised up even from the early years of academic instructional process. This vocation may be linked to emotions and aptitudes towards technological education. Particularly, students get in touch with these technological issues (namely STEM) during the Compulsory Secondary Education in Spain (12–16 years old).This work presents a preliminary evaluation of how relevant is Gardners multiple intelligence theory (MIT) in the teaching–learning process within the Technology Lessons. In this sense, MIT was considered as an explanation variable of the emotional response within the different educational parts (so-called syllabus units, SU) in the Technology spanish curriculum. Different intelligence style (IS) will orient the student to a vision of the engineering and technology. This work tries to identify which relationships can be established between IS and specific technology and engineering learning. This research involved up to 135 students were subsequently tested about their predominant (IS) and on the emotions that arouse in them when working with each SU. The results were statistically significant and only those with a Logic-arithmetic or Environmental IS were not affected by the SU.Best teaching and learning practicesare required for encouraging further engineering studies.

Nature Is the Answer: Water and Wastewater Treatment by New Natural-Based Agents

Environmental concerns regarding water quality are relevant nowadays because of their impact in human life. Persistent contaminants, such as heavy metals, dyes, or surfactants, have become a permanent menace to the fragile environmental equilibrium. Although their presence is due to the increasing level of industrial and economical development in large areas, it is even more mandatory to implement new and efficient systems for removing them from effluents.