Box-Behnken Design for optimization of Fenton-type reaction for water treatment using heterogeneous catalysts

Response Surface Methodology (RSM) was widely used in numerous research works for the optimization of different processes for liquid effluents treatment, since water pollution is one of the most serious environmental problem concerning human health and sustainability.1,2 RSM is a statistical technique applied to reduce the number of experiments, optimize and analyze the experimental independent parameters, that affect a process efficiency, and to generate a mathematical model which describes the process behavior.1,3 In this work, Box-Behnken design (BBD) was used for optimize the Fenton-type reaction using different bimetallic catalysts based in Rare Earth Elements with iron ion exchanged in zeolite (NaY) or a natural clay from Morocco. The effect of different experimental parameters such as, temperature, concentration of H2O2 and the heterogeneous catalysis used, was studied and optimized.We thank the Fundação para a Ciência e Tecnologia for financial support through Centre of Chemistry (UID/QUI/00686/2013 and UID/QUI/0686/2016) and BioTecNorte (operation NORTE-01-0145-FEDER-000004)info:eu-repo/semantics/publishedVersio

Moment arms of the deltoid, infraspinatus and teres minor muscles for movements with high range of motion: A cadaveric study

Background Moment arms are an indicator of the role of the muscles in joint actuation. An excursion method is often used to calculate them, even though it provides 1D results. As shoulder movement occurs in three dimensions (combination of flexion, abduction and axial rotation), moment arms should be given in 3D. Our objective was to assess the 3D moment arms of the rotator cuff (infraspinatus and teres minor) and deltoid muscles for movements with high arm elevation. Methods The 3D moment arms (components in plane of elevation, elevation and axial rotation) were assessed using a geometric method, enabling to calculate the moment arms in 3D, on five fresh post-mortem human shoulders. Movement with high range of motion were performed (including overhead movement). The humerus was elevated until it reaches its maximal posture in different elevation plane (flexion, scaption, abduction and elevation in a plane 30° posterior to frontal plane). Findings We found that the anterior deltoid was a depressor and contributes to move the elevation plane anteriorly. The median deltoid was a great elevator and the posterior deltoid mostly acted in moving the elevation plane posteriorly. The infraspinatus and teres minor were the greatest external rotator of the shoulder. The position of the glenohumeral joint induces changes in the muscular moment arms. The maximal shoulder elevation was 144° (performed in the scapular plane). Interpretation The knowledge of 3D moment arms for different arm elevations might help surgeons in planning tendon reconstructive surgery and help validate musculoskeletal models

Degradation of pollutants in water by Fenton-like oxidation over LaFe-catalysts: Optimization by experimental design

The effect of different parameters such as temperature, type of catalyst and hydrogen peroxide (H2O2) concentration on the degradation of pollutants in water by Fenton-like oxidation was studied by using the Box-Behnken design (BBD), an effective statistical model to design the experiments. Concerning the heterogeneous catalysts, three bimetallic catalysts with lanthanum (La) and iron (Fe) ion-exchanged into zeolites (NaY and ZSM5) and a natural clay from Morocco were prepared and used for Fenton-like oxidation of organic pollutants in water. Tartrazine (Tar, a food coloring compound known as E102) and caffeine (Caf, a stimulant drug present in popular beverages such as coffee and tea) were selected as pollutants due to their presence in several commercial products for daily consumption. The BBD model indicated that the optimum catalytic conditions for Fenton-like reaction with an initial pollutant concentration of 30 ppm at pH 3.0 were T = 40 ºC and 90 mM of H2O2. The maximum conversion values achieved with the best catalyst, LaFeZSM5, were 96.6% for Tar after 180 min and 51.0% for Caf after 300 min of reaction. To increase the conversion of Caf, a modified zeolite electrode was used for electro Fenton-like oxidation without H2O2, at room temperature

Valorization of Date Pits as an Effective Biosorbent for Remazol Brilliant Blue Adsorption from Aqueous Solution

In this work, the adsorption of Remazol Brilliant Blue (RBB) over raw date pits (RDPs) as an inexpensive adsorbent has been examined. In addition, all parameters such as the adsorbent mass, solution pH, RDP particle size, RBB initial concentration, and temperature on the adsorption of RBB influencing the adsorption procedure were studied to provide fundamental information of the adsorption equilibrium. The characterization of RDP material is investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). Based on the calculation, the kinetic rate of the adsorption was well modeled by pseudo-second-order and Langmuir isotherm. Surface functional groups of RDP have substantially been influenced by the adsorption characteristics of RBB. The capacity of the adsorption has achieved 105 mg/g and a removal efficiency of 90.4% at 1.5 g/L RDP mass, 40 mg/L initial dye concentration, pH 2, temperature of 328 K, 40 µm particle size, and contact time of 50 min. The capacity of the adsorption could reach 198 mg/g by increasing the ionic strength of RBB solution. Desorption tests showed that RDP adsorbent has the disadvantage of losing efficiency while reusing for many cycles. However, it still abundant and inexpensive. Therefore, RDP can be used as a potential low-cost bioabsorbent for the elimination of RBB from wastewater