Treatment of table olive processing wastewaters using novel photomodified ultrafiltration membranes as first step for recovering phenolic compounds

Table olive processing wastewaters (TOPW) have high salt concentration and total phenolic content (TPC) causing many environmental problems. To reduce them, ultrafiltration (UF) was applied for treating TOPW. However, NaCl, which is the main responsible of salinity in TOPW, and phenols are small molecules that cannot be separated by conventional UF membranes. They have serious problems caused by fouling, which can be overcome using membrane modification techniques. For these reasons, photomodification may be an effective technique to obtain a stream rich in TPC due to the changes in membrane surface properties. UV-modification in the presence of two hydrophilic compounds (polyethylene glycol and aluminium oxide) was performed to achieve membranes with high reductions of organic matter and to keep the TPC as high as possible. Commercial polyethersulfone (PES) membranes of 30 kDa were used. Surface modification was evaluated using FTIR-ATR spectroscopy and membrane performance was studied by calculating the rejection ratios of colour, chemical oxygen demand (COD) and TPC. Results demonstrated that UF is a useful pre-treatment to reduce organic matter from TOPW, obtaining a permeate rich in TPC. PES/Al2O3 membranes displayed superior antifouling properties and rejection values, keeping high the TPC (>95%). Therefore, UF using modified membranes is an appropriate and sustainable technique for treating TOPW.The authors thank the financial support of CDTI (Centre for Industrial Technological Development) depending on the Spanish Ministry of Science and Innovation. The authors also thank the Center for Biomaterials and Tissue Engineering (Universitat Politecnica de Valencia) for FTIR-ATR and contact angle measurements.García Ivars, J.; Iborra Clar, MI.; Alcaina Miranda, MI.; Mendoza Roca, JA.; Pastor Alcañiz, L. (2015). Treatment of table olive processing wastewaters using novel photomodified ultrafiltration membranes as first step for recovering phenolic compounds. Journal of Hazardous Materials. 290:51-59. doi:10.1016/j.jhazmat.2015.02.062S515929

Surface photomodification of flat-sheet PES membranes with improved antifouling properties by varying UV irradiation time and additive solution pH

Different polyethersulfone ultrafiltration membranes modified using UV irradiation in the presence of additives with different nature: hydrophilic aluminium oxide (Al2O3) nanoparticles and organic polyethylene glycol (PEG). The influence of the additive concentration, the irradiation time and the pH of the additive solution on several membrane characteristics related to its antifouling properties were investigated. These properties were analysed by means of hydrophilicity measurements (water contact angle, degree of modification, water permeability, porosity, and pore size), surface microscopic techniques (ATR-FTIR, SEM and AFM) and cross-flow filtration experiments using industrial wastewaters (residual brines from table olive processing wastewaters). Results showed that all the PES membranes modified with different PEG/Al2O3 concentrations improved the hydrophilicity of the membrane, except for membranes modified at pH 7. In addition, superior antifouling properties were provided by PES membranes modified with nano-sized Al2O3 at a concentration of 0.5%, low irradiation time (10 min) and acidic pH values (about pH 3). Therefore, surface membrane modification via UV irradiation with hydrophilic compounds is an appropriate technique to improve membrane performance applied in certain industrial fields.The authors of this work thank the financial support of CDTI (Centre for Industrial Technological Development) depending on the Spanish Ministry of Science and Innovation. The authors also thank the Center for Biomaterials and Tissue Engineering and the Electron Microscopy Service both from the Universitat Politecnica de Valencia.García Ivars, J.; Iborra Clar, MI.; Alcaina Miranda, MI.; Mendoza Roca, JA.; Pastor Alcañiz, L. (2016). Surface photomodification of flat-sheet PES membranes with improved antifouling properties by varying UV irradiation time and additive solution pH. Chemical Engineering Journal. 283:231-242. doi:10.1016/j.cej.2015.07.078S23124228

Fractionation of secondary effluents of wastewater treatment plants in view of the evaluation of membrane fouling in a further ultrafiltration step

[EN] BACKGROUNDUltrafiltration is used as tertiary treatment in wastewater treatment plants (WWTP) for wastewater reclamation. However, membrane fouling is the main drawback of the process. In this work a new effluent organic matter fractionation procedure with adsorption resins (XAD-8, XAD4 and IRA-958) has been applied without recovering the adsorbed fractions. In this way, strong and weak hydrophobic and charged hydrophilic substances of the dissolved organic matter (DOM) were removed for further ultrafiltration, in order to know the most fouling fraction. For this, secondary effluents of two WWTP and two membranes with different molecular weight cut-offs (100 kDa and 3 kDa) were used in ultrafiltration experiments in a laboratory plant. RESULTSThe hydrophobic substances (especially the strong hydrophobics) predominated over the hydrophilic compounds. Membrane fouling was higher for the membrane with the highest molecular weight cut-off (100 kDa). Thus, flux decline was around 25-47% higher than that measured for the 3 kDa membrane. The charged hydrophilic substances (CHi) were identified as the most fouling compounds with 100 kDa membrane. Reversible fouling was predominant. CONCLUSIONSThe proposed fractionation system enabled determination of the contribution of the different fractions to the DOM. (c) 2017 Society of Chemical IndustryThis work was supported by the Spanish Ministerio de Economia y Competitividad (CTM2014-54546-P).Ferrer-Polonio, E.; Mccabe, ME.; Mendoza Roca, JA.; Vincent Vela, MC. (2018). Fractionation of secondary effluents of wastewater treatment plants in view of the evaluation of membrane fouling in a further ultrafiltration step. Journal of Chemical Technology & Biotechnology. 93(5):1495-1501. https://doi.org/10.1002/jctb.5520S1495150193

Performance of a quasi-steady, multi megawatt, coaxial plasma thruster

The Los Alamos National Laboratory Coaxial Thruster Experiment (CTX) has been upgraded to enable the quasisteady operation of magnetoplasmadynamic (MPD) type thrusters at power levels from 2 to 40 MW for 10 ms. Diagnostics include an eight position, three axis magnetic field probe to measure magnetic field fluctuations during the pulse; a triple Langmuir probe to measure ion density, electron temperature, and plasma potential; and a time-of-flight neutral particle spectrometer to measure specific impulse. Here we report on the experimental observations and associated analysis and interpretation of long-pulse, quasisteady, coaxial thruster performance in the CTX device

Comparison of different removal techniques for selected pharmaceuticals

[EN] Recently, there is an emergence of endocrine-disrupting compounds, pharmaceuticals, and personal care products (EDC/PPCPs) as important pollutants to remove from drinking water and reclaimed wastewater. In this work, the efficiency of removing pharmaceuticals (PCs) from model aqueous solutions and raw wastewater with ultrafiltration (UF), nanofiltration (NF), activated carbon adsorption (AC), biological methods (SBR) and oxidation with ClO2 was investigated. Some treatments have also been used as combined processes: UF + NF, UF +AC, SBR + ClO2. Ibuprofen, Acetaminophen, Diclofenac, Sulfamethoxazole, Clonazepam, and Diazepam were selected as model compounds. In order to evaluate their removal, PC solutions were also considered at several operating conditions (pH, conductivity, concentration, and temperature), andoptimal conditions were obtained. Experiments wereperformedatusual PCconcentrations in wastewaters: 1000 ng/L for Ibuprofen and Acetaminophen, 300 ng/L for Diclofenac, Sulfamethoxazole, Clonazepam, and Diazepam. Separation was evaluated by liquid chromatography¿mass spectroscopy. Results indicated that the removal efficiency depends on their Log KOW, which is intrinsically related to their hydrophobicity and then,to their adsorption onto the surface (UF, NF, andAC).Also, NF,AC, and combined processes (UF + NF, UF +AC) were the most suitable separation techniques to obtain high removal efficiencies for most of the PCs used, except for Acetaminophen (which showed great removal efficacy using SBR). UF presented low removal yields for all PCs tested. ClO2 treatment was more effective at high concentration (50 mg ClO2/L). Furthermore, results also showed that there are significant differences on the performance of the processes applied and which treatment is the most effective for each PC analyzed. © 2015 Elsevier Ltd. All rights reserved.The authors of this work wish to gratefully acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness through the project CTM2013-42342-P.Vona, A.; Di Martino, F.; García-Ivars, J.; Picó, Y.; Mendoza Roca, JA.; Iborra Clar, MI. (2015). Comparison of different removal techniques for selected pharmaceuticals. Journal of Water Process Engineering. 5:48-57. https://doi.org/10.1016/j.jwpe.2014.12.011S4857

Nanofiltration as tertiary treatment method for removing trace pharmaceutically active compounds in wastewater from wastewater treatment plants

[EN] The ever-increasing occurrence and persistence of pharmaceutically active compounds (PhACs) in soils, sediments, drinking water supplies and wastewater effluents are a matter of serious environmental concern for governments and researchers worldwide. Nanofiltration as tertiary treatment method can be a viable and practical tool to remove these pollutants from aquatic environments. However, organic matter present in water sources can foul the membrane surface during operation, thus being potentially able to affect the membrane performance. Therefore, fouling mechanisms could heavily influence on the removal efficiencies. The purpose of this study was to investigate the implementation of three nano- filtration membranes (TFC-SR2, NF-270 and MPS-34) and to study both the rejection of trace PhACs and the fouling mechanisms for each membrane as a function of feed solution pH. Fouling mechanisms were predicted by Hermia's model adapted to cross-flow configurations. Results demonstrated that higher removals were obtained at slightly alkaline pH, especially for anionic trace PhACs. At the same conditions, more severe fouling was observed, which resulted in strong flux declines and an increase in hydrophobicity. This indicates that the attached organic matter on the membrane surface acts as a secondary selective barrier for separation.The authors thank the financial support from the Spanish Ministry of Economy and Competitiveness through the project CTM2013-42342-P. Likewise, the authors also express their acknowledge to the personnel of the Carraixet WWTP for the kind supply of secondary effluent samples.García-Ivars, J.; Martella, L.; Massella, M.; Carbonell Alcaina, C.; Alcaina-Miranda, MI.; Iborra Clar, MI. (2017). Nanofiltration as tertiary treatment method for removing trace pharmaceutically active compounds in wastewater from wastewater treatment plants. Water Research. 125:360-373. https://doi.org/10.1016/j.watres.2017.08.070S36037312

Fouling mechanisms of ultrafiltration membranes fouled with whey model solutions

In this work, three ultrafiltration (UF) membranes with different molecular weight cut-offs (MWCOs) and made of different materials were fouled with several whey model solutions that consisted of bovine serum albumin (BSA) (1% w/w), BSA (1% w/w) and CaCl2 (0.06% w/w in calcium) and whey protein concentrate (WPC) with a total protein content of 45% w/w at three different concentrations (22.2, 33.3 and 44.4 g·L− 1). The influence of MWCO and membrane material on the fouling mechanism dominating the UF process was investigated. Experiments were performed using two flat-sheet organic membranes and a ceramic monotubular membrane whose MWCOs were 5, 30 and 15 kDa, respectively. Hermia's models adapted to crossflow UF, a combined model based on complete blocking and cake formation equations and a resistance-in-series model were fitted to permeate flux decline curves. The results demonstrated that permeate flux decline was accurately predicted by all the models studied. However, the models that fitted the best to permeate flux decline experimental data were the combined model and the resistance-in-series model. Therefore, complete blocking and cake formation were the predominant mechanisms for all the membranes and feed solutions tested.The authors of this work wish to gratefully acknowledge the financial support of the Spanish Ministry of Science and Innovation through the project CTM2010-20186.Corbatón Báguena, MJ.; Alvarez Blanco, S.; Vincent Vela, MC. (2015). Fouling mechanisms of ultrafiltration membranes fouled with whey model solutions. Desalination. 360:87-96. https://doi.org/10.1016/j.desal.2015.01.019S879636

Enhancement in hydrophilicity of different polymer phase-inversion ultrafiltration membranes by introducing PEG/Al2O3 nanoparticles

The influence of the modification by additives in the characteristics of several ultrafiltration polymeric membranes was studied. Three asymmetric membranes with similar pore size (molecular weight cutoff (MWCO) of around 30 kDa) but different materials and pore microstructures – polysulfone, polyethersulfone and polyetherimide – were used. Effects of two different hydrophilic additives on membrane structure and the resulting performance were compared to determine the material with the best antifouling properties. Polyethyleneglycol (PEG) and alumina (Al2O3) were employed as additives in the phaseinversion method, N,N-Dimethylacetamide and deionized water were used as solvent and coagulant, respectively. Membranes were characterized in terms of hydraulic permeability, membrane resistance, MWCO profile and hydrophilicity (by membrane porosity and contact angle). The cross-sectional and membrane surface were also examined by microscopic techniques. Membrane antifouling properties were analysed by the experimental study of fouling/rinsing cycles using feed solutions of PEG of 35 kDa. Permeation and morphological studies showed that the addition of PEG/Al2O3 results in formation of a hydrophilic finger-like structure with macrovoids, whereas the addition of Al2O3 results in the formation of a hydrophilic structure with a dense top layer with Al2O3 nanoparticles and a porous sponge-like sublayer. Furthermore, polyethersulfone/PEG/Al2O3 membranes displayed superior antifouling properties and desirable ultrafiltration performance.The authors of this work thank the financial support of CDTI (Centre for Industrial Technological Development) depending on the Spanish Ministry of Science and Innovation. The authors also thank the Center for Biomaterials and Tissue Engineering (Universitat Politecnica de Valencia) for contact angle measurements and BASF (Germany) and General Electric (United States) for supplying the polymers used.García Ivars, J.; Alcaina Miranda, MI.; Iborra Clar, MI.; Mendoza Roca, JA.; Pastor Alcañiz, L. (2014). Enhancement in hydrophilicity of different polymer phase-inversion ultrafiltration membranes by introducing PEG/Al2O3 nanoparticles. Separation and Purification Technology. 128:45-57. doi:10.1016/j.seppur.2014.03.012S455712

Development of fouling-resistant polyethersulfone ultrafiltration membranes via surface UV photografting with polyethylene glycol/aluminum oxide nanoparticles

Polyethersulfone ultrafiltration membranes prepared via immersion precipitation with similar pore size were modified using UV irradiation with two nano-sized hydrophilic compounds of a different nature (an organic compound and a metal oxide). Effects of PEG/Al2O3 nanoparticles on membrane structure and the resulting performance were compared to determine the material with the best antifouling properties. Membranes were characterized by hydrophilicity (water contact angle, porosity, equilibrium water content and average pore radius), surface microscopic techniques (ATR-FTIR, SEM, EDX and AFM) and cross-flow ultrafiltration experiments (hydraulic permeability, membrane resistance and antifouling measurements). Membrane antifouling properties were analyzed by several fouling/rinsing cycles using feed solutions of PEG of 35,000 g mol 1 with a concentration of 5 g L 1.Water contact angle measurements, ATR-FTIR spectra, SEM images and EDX analysis indicated the presence of PEG/Al2O3 nanoparticles on the membrane surface. All UV-grafted membranes had higher hydraulic permeability than the unmodified membrane. Furthermore, polyethersulfone membranes photografted with 2.0 wt% PEG and 0.5 wt% Al2O3 displayed superior antifouling properties and desirable performance compared to all membranes tested. Therefore, this study proved that UV photografting of PEG/Al2O3 onto membrane surfaces is an appropriate technique for modifying polyethersulfone membranes to minimize membrane fouling.The authors of this work thank the financial support of CDTI (Centre for Industrial Technological Development) depending on the Spanish Ministry of Science and Innovation. The authors also thank the Center for Biomaterials and Tissue Engineering (Universitat Politecnica de Valencia) for ATR-FTIR and contact angle measurements and BASF (Germany) for supplying the polymers used.García Ivars, J.; Iborra Clar, MI.; Alcaina Miranda, MI.; Mendoza Roca, JA.; Pastor Alcañiz, L. (2014). Development of fouling-resistant polyethersulfone ultrafiltration membranes via surface UV photografting with polyethylene glycol/aluminum oxide nanoparticles. Separation and Purification Technology. 135:88-99. doi:10.1016/j.seppur.2014.07.056S889913

Chemical, Structural, and Morphological Changes of a MoVTeNb Catalyst during Oxidative Dehydrogenation of Ethane

MoVTeNb mixed oxide, a highly active and selective catalyst for the oxidative dehydrogenation of ethane to produce ethylene, exhibits the so-called M1 and M2 crystalline phases. The thermal stability of the MoVTeNb catalytic system was assessed under varying reaction conditions; to this end, the catalyst was exposed to several reaction temperatures spanning from 440 to 550 °C. Both the pristine and spent materials were analyzed by several characterization techniques. The catalyst was stable below 500 °C; a reaction temperature of ≥500 °C brings about the removal of tellurium from the intercalated framework channels of the M1 crystalline phase. Rietveld refinement of X-ray diffraction patterns and microscopy results showed that the tellurium loss causes the progressive partial destruction of the M1 phase, thus decreasing the number of active sites and forming a MoO2 crystalline phase, which is inactive for this reaction. Raman spectroscopy confirmed the MoO2 phase development as a function of reaction temperature. From highresolution transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses it was noticed that tellurium departure occurs preferentially from the end sides of the needlelike M1 crystals, across the [001] plane. Detailed analysis of a solid deposited at the reactor outlet showrf that it consisted mainly of metallic tellurium, suggesting that the tellurium detachment occurs via reduction of Te4+ to Te0 due to a combination of reaction temperature and feed composition. Thus, in order to sustain the catalytic performance exhibited by MoVTeNb mixed oxide, hot spots along the reactor bed should be avoided or controlled, maintaining the catalytic bed temperature below 500 °C.This work was financially supported by the Instituto Mexicano del Petroleo.Valente, JS.; Armendariz-Herrera, H.; Quintana-Solorzano, R.; Del Angel, P.; Nava, N.; Masso Ramírez, A.; López Nieto, JM. (2014). Chemical, Structural, and Morphological Changes of a MoVTeNb Catalyst during Oxidative Dehydrogenation of Ethane. ACS Catalysis. 4:1292-1301. doi:10.1021/cs500143jS12921301