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Green energy production connected with global warming is one of the hottest topics for industry, technology, and life science. Microalgae culture and its potential for industrial applications in CO2 fixation from flue gases for second generation biofuels and many other valuable metabolites’ production has received much attention in recent years. The goal of this review is to combine all the key knowledge obtained in state of the art studies in recent years about the modeling of photobioreactors (PBRs). In order to develop the complex PBR phenomenological model, we considered it as a system and applied the theory of system analysis on PBR. Special attention was given to decomposition principles of this theory where the PBR system was divided into sub-systems. Furthermore, this review shows how to combine the knowledge from modeling of sub-systems by taking into account relationships between them, and how such interrelationships influence the overall PBR modeling procedure for the particular microalgal cultivation process. The result of this work is a successful development of a complex PBR phenomenological model, which was presented as an independent original authors’ work.

This study evaluates the application of the vegetal activated carbon (AC), vegetable AC impregnated with Ag and Cu (0.08% m/m) and cationic SupergelTM SGC650H resin for adsorption of Fe3+ and Pb2+ ...

The objective of this study was the toxicity evaluation of landfill leachate samples both raw and after treatment by photo-Fenton (PF), biological (Bio) and photo-Fenton followed by biological (PF-Bio) processes. The organisms Artemia salina and Lactuca sativa were exposed to the leachate in different dilution. In the phytotoxicity evaluation, the inhibition of root (RGI) and radicle (RAGI) growth, and the number of germinated seeds (GR) were evaluated. In the ecotoxicity analysis, the 50% lethal dose (LD

The intense use of antibiotics and their presence in water bodies has risen serious health and environmental concerns. Adsorption stands out as a promising method for the treatment of such persistent contaminants; however, a suitable adsorbent material and operational conditions must consider the specificities of one target pollutant. For an adequate process development, a comprehensive understanding of the involved mechanisms and phenomena are crucial. In this context, the objective of this work was to evaluate the potential of a biochar produced from tilapia fish bone-residue for tetracycline (TC) adsorption, in batch and fixed-bed systems. For this, the biochar was characterized in terms of its textural and surface chemistry properties. Also, a mathematical model was used to support the understanding of mass transfer and equilibrium mechanisms as well as to obtain relevant parameters to support the prediction and scale-up of the adsorption system in fixed bed columns. First, the biochar production was investigated, with the TC removal capacity as a response variable, then biochar (in the best carbonization condition – 550 °C) was submitted to the characterization. In the mathematical modeling, three different rate-limiting steps were applied to kinetic data, namely, external mass transfer resistance (EMTR), internal mass transfer resistance (IMTR) and monolayer-multilayer adsorption (MMA). Based on equilibrium and kinetic parameters obtained in the batch mode, a hybrid (statistical-phenomenological) model was developed to predict the behavior of the breakthrough curves in fixed bed column. IMTR (homogeneous intraparticle diffusion) and BET isotherm models adequately described the kinetic and equilibrium data in batch system, indicating that the adsorption kinetics is governed by the internal diffusion of the TC within the biochar porous structure and that the adsorption may undergo multilayer formation for high TC concentration levels. The biochar characterization showed presence of apatites and predominance of a mesoporous structure with a 124 m2 g−1 superficial area. Near-neutral pH conditions, namely, between the isoelectric point of the TC (5.30) and the zero point of surface charge of the biochar (7.81) favored the adsorption process due to electrostatic attraction. Based on the batch parameters the hybrid phenomenological model was able to adequately predict the fixed-bed column performance, which was validated by independent experimental data. Therefore, the predictive model can be useful for adsorption systems scale-up, while presenting potential to predict and optimize fixed bed operational conditions.

A phenomenological model for multilayer liquid phase adsorption in closed and batch system was developed to assess the diffusional resistances and the adsorption rate-limiting steps. Equilibrium, kinetic and thermodynamic results indicated a multilayer adsorption behavior, wherein two adsorption steps were identified: (i) monolayer adsorption, with chemisorption characteristic binding energy due to synergistically electrostatic and H-bond intermolecular interactions; (ii) multilayer adsorption, favored by high dye concentrations and temperatures, however presenting a physical biding energy, related to less intense interactions such as H-bond and van der Waals forces. Additionally, dye aggregation in the liquid phase was observed and investigated. The proposed adsorption model allowed to investigate physically the kinetics, equilibrium and thermodynamics through a unique approach and to elucidate the mechanisms in distinct operational conditions. Hence, this mechanistic and predictive model can be used for the optimization and scale-up of the multilayer adsorption processes.

In this study, a time-integrated performance index (TIPI) was proposed to assess the compromise between amounts of removed metallic ions (RMI) and the consumed electric energy (CEE) in wastewater treatment systems based on the electrocoagulation (EC) process. An aluminum electrode-based EC reactor along with a Zn2+ ion-based electrolytic medium was used to assess the effect of electrical conductivity (κ) in low | values (215–415 μS cm−1) was used to highlight κ effects on total electric voltage (UEC) and EC performance. Measurements of metallic ion concentrations, κ and UEC were performed in time. A Nernst-Planck equation-based mathematical model for the time description of κ was proposed. In all EC tests, time-dependent behaviors on κ, UEC and electric current were observed. The κ experimental data were well fitted by the κ model, showing profiles modulated by the time behavior of the metallic ion concentrations. The maximum TIPI value (1.2/Wh) was achieved about 10 min electrolysis time, dropping quickly due to a substantial reduction (350 to 50 μS cm−1 after 60 min) in κ and, consequently, an increase in CEE (up to 2 Wh after 60 min). Thus, this drop in κ value became more evident at the end of shorter electrolysis times related to the low κ conditions driving towards a significant loss in TIPI. In a global context of the EC performance, TIPI has brought another perspective to address in an optimized EC process, looking for the highest values within a steady state.

In this work, an innovative mathematical approach for the total electric voltage in the electrocoagulation process (EC) was proposed. Contributions of electrodes activation and ions species transfer were modeled by analytical solving the non-steady Nernst-Planck equation. The electrical conductivity was adequately represented in terms of available positive ions species. A time-dependent equation that resembles a desorption-diffusion process was found to represent the electrode activation voltage. An Al electrode-based EC reactor was used to perform EC tests for assessing each electric phenomenon voltage. The data of electrical conductivity were well fitted by its proposed model, highlighting its effects on the total voltage. The anode activation voltage was responsible for the starting transient stage and modulating the total voltage profile. Finally, it could state that the time-dependent electrical conductivity has influenced the total voltage profile and drove the pollutant removal performance, acting on both activation and electric migration voltages intrinsically.

Made available in DSpace on 2020-12-12T01:08:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Nd(OH)3-ZnO composites were synthesized with three content of Neodymium (1, 3 and 5 wt%) and characterized in terms of their structural, morphological, vibrational, optical, surface, photocatalytic and antimicrobial properties. The Nd(OH)3-ZnO composites are constituted by ZnO, which showed hexagonal structure, three-dimensional morphology analogous to an arrangement of flowers with hexagonal rods, and the Nd(OH)3 in the hexagonal phase with irregularly spherical shape. The presence of the Nd(OH)3 in the composites promoted some structural degree of disorder in the ZnO network as well as interstitial defects and oxygen vacancy, which improved photocatalytic and antimicrobial activity. From the Box-Behnken design and response surface methodology, it was determined that the 1Nd(OH)3-ZnO composite showed the highest photocatalytic activity, which was attributed to its higher crystallinity, smaller crystallite size and particle width, band gap energy close to ZnO and lower recombination rate compared to ZnO. Nd(OH)3-ZnO composites showed higher antimicrobial activity against E. coli and S. aureus than ZnO pure, evidencing the synergistic effect between Nd(OH)3 and ZnO in the composites. Therefore, this study highlights the synthesis of Nd(OH)3-ZnO composites combining zinc oxide and neodymium hydroxide with excellent photocatalytic and antimicrobial activity, which can be used in different practical applications such as luminescent material, photocatalyst and antimicrobial agent. Program of Post-Graduation in Chemical Engineering State University of West Parana, P.O. Box 520 CDMF LIEC Federal University of São Carlos, P.O. Box 676 Modeling and Molecular Simulations Group São Paulo State University UNESP Modeling and Molecular Simulations Group São Paulo State University UNESP

The objective of this study was to evaluate the removal of the direct black ECO TFA (DBET) dye from tannery industry by cassava root husks (CRH) from starch industry as a biosorbent material. For this, CRH biosorbent was characterized, in terms of textural parameters and functional groups. Based on the results, it was verified that CRH is a nonporous material, also DBET dye adsorption takes place, especially, in hydroxyl and carboxyl groups abundantly present in CRH biosorbent. Preliminary adsorption tests evidenced the most favorable operational conditions, namely, particle size mixture, lower temperature 30 °C, higher stirring speed 150 rpm (due to lower diffusional resistances) and pH 2.0 (favoring electrostatic interactions between DBET dye and CRH biosorbent). Adsorption kinetics studies evidenced favorable kinetics, described by the pseudo-second-order model, indicating that the adsorption itself as the of the overall mass transfer process, rather than diffusional ones. Equilibrium data was described by Langmuir isotherm within the evaluated temperature range (30–50 °C). Nevertheless, near-linear isotherm profiles (similar to Henry’s law) were observed. Thermodynamic parameters indicated an exothermic and physisorption process (∆Hads = −14.73 kJ mol-1). Overall, equilibrium results along with functional groups characterization and identified intermolecular interactions (e.g. electrostatic, hydrophobic and H-bond) point out that multilayer sorption mechanism most likely rules the DBET dye uptake by the CRH biosorbent. Thus, the results evidence the potential of CRH biosorbent for direct dyes removal, given the observed technical-operational features along with its renewable and residual characteristics, which provides both economic and environmental advantages for such biomaterial.

This paper reports the development of an electrochemical sensor using electrospun polymeric fibers of PBAT (poly (butylene adipate co-terephthalate))/PLA (poly (lactic acid) containing functionalized carbon nanotubes (MWCNTs) and further calcined (at 500 °C under N2). The morphologies of the electrospun fibers were verified by SEM and those containing MWCNTs presented lower average diameter of 1.76 ± 0.30 μm against 3.67 ± 0.88 μm for the fibers of neat PBAT/PLA. Fourier transform infrared (FTIR) spectra of the polymeric fibers indicated possible interactions between the MWCNTs and the C O functional group. Thermogravimetric analysis (TGA) curves demonstrated slight increase of the stability of the PLA and lower thermal stability of the PBAT. Analyzes through differential scanning calorimetry (DSC) data showed that the interactions occur preferentially with the aliphatic segments of polymer chains; and corroborated the data from FTIR. Also, FTIR and X-ray powder diffraction (DRX) indicated, respectively, decrease on carboxylic groups amount and lamella formation on functionalized MWCNTs due to the PBAT/PLA/MWCNTs electrospun fibers calcination. The electrochemical measurements performed using sensor built based on the as-obtained calcined material showed that the sensor is promising for the determination of metronidazole in aqueous environment.

Modeling as a tool solves extremely difficult tasks in life sciences. Recently, schemes of culturing of microalgae have received special attention because of its unique features and possible uses in many industrial applications for renewable energy production and high value products isolation. The goal of this review is to present the use of system analysis theory applied to microalgae culturing modeling and process development. The review mainly focuses on the modeling of the key steps of autotrophic growth under the integral biorefinery concept of the microalgae biomass. The system approach follows systematically a procedure showing the difficulties by modeling of sub-systems. The development of microalgae kinetics and computational fluid dynamics (CFD) studies were analyzed in details as sub-systems in advanced design of photobioreactor (PBR). This review logically follows the trends of the modeling procedure and clarifies how this approach may save time and money during the research efforts. The result of this work is a successful development of a complex PBR mathematical analysis in the frame of the integral biorefinery concept.

In this work, the effects of the factors light intensity, photoperiod, pH, NaCl and nitrogen concentration were investigate on the carotenoids response of Tetradesmus acuminatus (LC192133.1) cultures. Analysis of variance (α = 0.10) suggested significant effect mainly of the light intensity and photoperiod factors. The applied regression models, considering these factors, have allowed to estimate the production of carotenoids with precision (0.90 ≤ R² ≤ 0.95). The optimization of the light intensity and photoperiod values resulted in the maximum production of carotenoids in mg g−1 (85 μmol m−2 s−1; 15.8:8.2 h light:dark) and in mg L−1 (595 μmol m−2 s−1 for 24 h). The experimental validation of the results showed syntheses of 7.6 mg g−1 astaxanthin and 9.1 mg g−1 β-carotene; as well as the production of 12.1 mg L−1 astaxanthin and 12.8 mg L−1 β-carotene. Results indicated that the cultivation of Tetradesmus acuminatus (LC192133.1) under optimized conditions of energy intensity and photoperiod allowed the improvement of carotenoid production.

In this work, the photo-Fenton process with ferrioxalate induction has been applied to perform the degradation of the organic matter from a textile effluent based on a full factorial design in order to work at its optimized condition along with obtaining a low toxicity. Experimental tests based on a three-level full factorial design (FF 33) were performed, properly varying initial pH, Fe3+ ion concentration and H2O2 concentration and using COD and color removal as response variables. Additionally, 240-min UV irradiation and 150-rpm shaking speed were set at all runs. The FF 33 experimental data were statistically represented by a quadratic polynomial function validated by the ANOVA test, suggesting the individual and combinate effects of fundamental parameters on removals. In this context, an improvement on COD removal and discoloration up to 93 and 99%, respectively, was found. The best condition of 8000 mg L−1 H2O2, 170 mg L−1 Fe3+ and initial pH 2.8 was applied to assess the toxicity effect. An extending on experiment time of about 120 min was suggested by Artemia salina-based bioassays to get a lower toxicity in environmental safety context. Finally, the photo-Fenton process with ferrioxalate induction was verified to favor and improve the pollutant degradation with higher COD removals, faster reaction kinetics and a greater availability of iron ions in comparison with the conventional photo-Fenton reaction. Besides, treated effluent with evident reduction in toxicity could be disposed without affecting the water body quality.

In this work, Tetradesmus sp. was investigated regarding biomass and pigment production. The cultivation of Tetradesmus sp. was carried out in a BG-11 medium in addition to a vertical tubular photobioreactor (PBR) irradiated with different spectral combinations and intensities, within a 24:00 h photoperiod. The LEDs emitting light with white; red; yellow; green and blue spectrum were used alone and/or combined, with intensities varying from 13 to 190 μmol m−2 s−1. ANOVA suggested significant effects of the light combination, intensity and interaction between the factors on biomass, carotenoid and chlorophyll responses. The blue light accelerated the growth of Tetradesmus sp. in all three experiments. The combinations white:green (95 μmol m−2 s−1), red:blue (50 μmol m−2 s−1) and blue (25 μmol m−2 s−1) favored biomass growth; while white:green (190 μmol m−2 s−1), red:green (50 μmol m−2 s−1) and red (25 μmol m−2 s−1) favored the synthesis of carotenoids and chlorophylls. Culture reproduction under the spectral regions favoring pigment synthesis indicated that Tetradesmus sp. was photostimulated to synthesize both pigments, especially with red:green (50,50%) at 50 μmol m−2 s−1, where the highest production of carotenoids (6.09 ± 0.29 mg (g biomass)−1) and chlorophyll a (10.08 ± 0.75 mg (g biomass)−1) was obtained.

The application of innovative strategies to develop cost-effective closed photobioreactors (PBRs) aiming high-density microalgae culture is the way to overcome the predominance of algae ponds against closed systems in the growing market of overall microalgae products. Hence, this paper focused on the development of a flat-plate PBR (FP-PBR) with improved fluid dynamics (FD), based on the system analysis theory, to achieve the maximum possible high-density culture (HDC). Therefore, 10-L FP-PBRs were built with and without internal bubble dispersers. The computational fluid dynamics (CFD) concept based on the Euler-Euler model was applied to study the FD of FP-PBRs through the software Comsol Multiphysics®. The system was considered as a 2D lateral cut of the three FP-PBRA – no disperser; FP-PBRB – simple disperser; and FP-PBRC – complex disperser. The simulations indicated that in PBRB and PBRC the flashing light effect was achieved. To prove the applied strategy, real photoautotrophic experiments with Poterioochromonas malhamensis were designed and performed. Comparison between FP-PBRA and FP-PBRC performance showed a drastic improvement in microalgae growth, up to 270% in biomass concentration. Finally, the application of the system analysis theory along with CFD stands out as a unique and powerful tool for system modelling, optimization and design.

This work focused in the evaluation of Oreochromis niloticus fish scales (FS) as biosorbent material in the removal of Zn from a synthetic effluent based on automotive battery industry effl...

In this work, the physicochemical and morphological characterization of fish scales and an evaluation of their adsorption of reactive blue 5G (RB5G) dye were performed. The analysis of N2 physisorption, pHZPC, SEM–EDX, XRD and FTIR was carried out. Adsorption experiments were performed in batch and closed system. From N2 physisorption studies, we obtained values of the specific surface area, total pore volume and average pore diameter as 2.6 m2 g−1, 0.003 cm3 g−1 and 20.6 A, respectively. The pHZPC was estimated as 7.6. The presence of hydroxyapatite and collagen fibres in the structure of the scales was observed in SEM–EDX, XRD and FTIR results. Furthermore, leaching of mineral phase mainly occurs during the adsorption process in acid medium (pH 2), although, in neutral and alkaline media (pH 7 and 10), it is less pronounced. The FTIR spectra indicate that the amides functional groups from collagen structure are responsible for RB5G dye adsorption. Comparing the RB5G dye uptake at different initial pH values (2, 7, 10), a higher capacity was achieved in acidic medium. The equilibrium adsorption data of RB5G dye at pH 2 showed a maximum capacity of 241.20 mg g−1 with fast kinetics.

We studied the effect of drying temperature of sugarcane bagasse (SB) on sorption of reactive blue 5G (RB5G) dye to test whether SB is a suitable biosorbent for industrial dye removal. First we assessed a set of SB characteristics that could influence the sorption capacity of dried biomass. Kinetic drying of the SB biomass was measured at different drying temperatures, ranging from 30 °C to 80 °C. We used a static gravimetric method to perform equilibrium moisture sorption experiments at drying temperatures of 35–65 °C. In addition, we measured activation energy and net isosteric heat of sorption. SB biomass was characterized as a heterogeneous low-porous and hygroscopic material, with a series of functional groups on its surface. A Lewis thin-layer model best represented the kinetic drying data. In addition, moisture diffusion into the SB biomass was characterized by a rate-controlling step in the drying process. Equilibrium moisture sorption data showed the expected effects of temperature controlling the sorption capacity and a multilayer sorption process. A sigmoidal sorption isotherm data was best represented by a BET model. A high energy demand is required for moisture removal from biomass as suggested by the measured isosteric heat of moisture sorption. Drying temperature did not influence the RB5G adsorption capacity of bagasse, therefore any drying temperature in the range of 30 °C to 80 °C could be used to make this material feasible as an industrial adsorbent.

In this work, the removal of reactive blue 5G (RB5G) dye using the drying biomass of banana pseudostem (BPS) was investigated. The characterization of BPS particles was performed. Improvement in the RB5G dye removal performance at the following sorption conditions was evidenced: pH 1, 30°C sorption temperature and 40 rpm shaking, regardless of the particle size range. Kinetic RB5G dye sorption data obtained at better conditions fit well in an Elovich model. A combined Langmuir-BET isotherm model provides a good representation of the RB5G dye equilibrium sorption data, which shows the evidence of a physical sorption process on the BPS surface. Based on the results, the removal of RB5G dye molecules by BPS is based on a physical sorption process.

The uptake of Cd(2+) and Pb(2+) ions by a soybean hull (SH) biosorbent in single and binary systems has been investigated. Sorption tests regarding SH in natura and chemically treated were carried out testing a suitable value range of solution pH, sorption temperature and shaking velocity. Sorption capacity is improved at pH 4, 30 °C temperature and 100 rpm. When a strong base is applied, a related-to-untreated SH increasing of 20% in the sorption capacity of Pb(2+) ions was observed, but with poor results for Cd(2+) uptake. Additionally, a relatively strong decreasing in both sorption capacities of Pb(2+) and Cd(2+) ions was evidenced for all acidic treatments. Regarding untreated SH, kinetic sorption data of both metals were well-interpreted by a pseudo second-order model and a rate-limiting step on the basis of an intra-particle diffusion model was suggested to occur. An inhibitory effect of Pb(2+) diffusion over Cd(2+) one was observed, limiting to reach the obtained maximum sorption capacity in single system. Maximum adsorption capacities of 0.49 and 0.67mequivg(-1) for Cd(2+) and Pb(2+), respectively, were predicted by the Langmuir isotherm model that reproduced well the equilibrium sorption data for single systems. The inhibitory effect of one metal over the other one was verified in equilibrium sorption data for binary systems interpreted on the basis of a modified extended Langmuir isotherm model, predicting changes in metal affinity onto the SH surface. Finally, SH is an alternative biosorbent with a great potential for the wastewater treatment containing cadmium and lead ions.

The treatment of a real textile wastewater was accomplished using a conventional photo-Fenton reaction and mediated by different ferric-organic ligand complexes, performed in lab and pilot scale photoreactors irradiated by simulated and natural solar radiation, respectively. The textile wastewater presents a dark-blue colour, alkaline pH, a high organic content (COD = 1239 mg O-2 L-1; DOC = 408 mg C L-1) and moderate biodegradability (BOD5/COD = 0.16). The conventional solar-photo-Fenton reaction showed limited efficiency in the mineralization of the textile wastewater, which is characterized by a fast initial dissolved organic carbon decay in the absence of light, mainly attributed to the formation of ironorganic pollutants complexes with a low solubility at acidic pH values, leading to iron precipitation, followed by a very slow reaction rate under UV-visible light associated to (i) low amounts of dissolved iron and (ii) low photoactivity of the iron precipitates. The addition of the organic ligands, such as oxalic acid, citric acid and EDDS, enhanced significantly the photo-Fenton reaction, avoiding the formation of ironorganic pollutants complexes, and consequently increase of the quantum yield for ferrous ions production through the photodecarboxylation of ferric-organic ligands complexes. The catalytic activity of the iron-organic ligand complexes increased in the following order: Fe(III)-EDDS < Fe(III)-citrate < Fe(III)-oxalate. All the tested processes mediated by ferric-organic ligands complexes contributed to an effective decolourization and mineralization, but the most efficient system was the photo-Fenton-ferrioxalate reaction with an optimum catalyst concentration of 100 mg Fe3+ L-1, pH 2.8, temperature of 30 degrees C leading to complete decolourization and 69.1% mineralization after less than 8.8 kJuv L-1. An enhancement of the wastewater biodegradability was observed during the photo-Fenton-ferrioxalate reaction.

In this work, deleterious effects in soils due to the presence of dielectric fluids were investigated. For this purpose, vegetable (Envirotemp® FR3) and mineral (Lubrax AV 66 IN) oils were used for simulating a set of soils contaminated in different oil contents (0.5, 1.0, 2.0, 2.5, 5.0, 7.5 and 10%) in which three 120-days soybean crop periods (SCP) were carried out using the species Glycine max (L.) Merr. Both soil and soybean plant samples were analysed on following the changes on chemical attributes, content of oils and greases (COG) in soils and phytotechnical characteristics of soybean plant. No significant changes on soil chemical attributes were found. For a 0.5% vegetable oil fraction, COG removals of 35, 60 and 90% were observed after the 1st, 2nd, and 3rd SCPs, respectively, whereas removals of 25, 40 and 70% were observed for 0.5% mineral oil fraction after the 1st, 2nd, and 3rd SCPs, respectively. There was an effectively accumulated removal on all tested oil fractions as being proportional to the integrated 120-days SCPs, suggesting a lesser number of crops for a complete abatement of oil fraction in soil. A 100% recovery on the seedlings emergence fractions was also evidenced, revealing that at least a number of 7 and 9 SCPs should be applied continuously in soils contaminated by vegetable and mineral oils, respectively, in order to no longer jeopardize soybean plant growth. Finally, an empirical prediction of the number of SCPs necessary for the complete removal of oil from the soil was proposed.

The complex use of the algae biomass highlights the trends in green and innovative technologies of high priorities in EU program Horizon 2020. This part of the chapter will combine the obtained key knowledge about the modeling of different photobioreactor (PBR) designs. Innovative approaches and achievements in modeling of microalgal kinetics connected with light intensity, hydrodynamics, and mass transfer phenomena in PBRs will be underlined. Furthermore, we will discuss applicability of the complex models to optimize overall microalgae process for bioenergy production. In the second part of the chapter technoeconomic analysis will be performed to determine cost viability of algae process for bioenergy. Such study varies depending upon algae-processing techniques, involved equipment, and downstream steps of desired products. The most industrially viable algae metabolite products for bioenergy and some high-value coproducts will be discussed through the life cycle assessment approach.

Reactive blue 5G dye removal in a fixed-bed column packed with Dowex Optipore SD-2 adsorbent was modelled. Three mathematical models were tested in order to determine the limiting step of the mass transfer of the dye adsorption process onto the adsorbent. The mass transfer resistance was considered to be a criterion for the determination of the difference between models. The models contained information about the external, internal, or surface adsorption limiting step. In the model development procedure, two hypotheses were applied to describe the internal mass transfer resistance. First, the mass transfer coefficient constant was considered. Second, the mass transfer coefficient was considered as a function of the dye concentration in the adsorbent. The experimental breakthrough curves were obtained for different particle diameters of the adsorbent, flow rates, and feed dye concentrations in order to evaluate the predictive power of the models. The values of the mass transfer parameters of the mathematical models were estimated by using the downhill simplex optimization method. The results showed that the model that considered internal resistance with a variable mass transfer coefficient was more flexible than the other ones and this model described the dynamics of the adsorption process of the dye in the fixed-bed column better. Hence, this model can be used for optimization and column design purposes for the investigated systems and similar ones.

The aim of this study is to evaluate the fluoride removal from contaminated water using a new adsorbent material of high efficiency to obtain drinking water. The ZrCl4-graphene supported on vegetal activated carbon composite (G-ZrCl4/VAC) was synthesized and characterized using transmission and scanning electron microscopy, N2 physisorption, energy dispersive X-ray spectrometry, Fourier transform-infrared spectroscopy, X-ray diffraction, and Raman spectroscopy. Furthermore, the point of zero charge was determined. The G-ZrCl4/VAC was evaluated for fluoride adsorptive removal from water under several operating conditions in batch system. The results indicated that fluoride adsorption by G-ZrCl4/VAC is favored at low pH values with the maximum adsorption at pH 2, corresponding to 97.22% removal. Among the conditions of temperature and agitation evaluated, the best results were achieved at 30 °C and 130 rpm, with removal percentages equal to 47.78 and 48.48%, respectively. The equilibrium of the system was achieved in 5 h of operation. The pseudo-first order kinetic model was the one that best described the kinetic data, while the equilibrium data were best described by the Langmuir isotherm with maximum adsorption capacity equal to 3.89 mg g−1. Therefore, the results obtained show that the material synthesized has a great capacity for adsorption and demonstrate the viability of use of G-ZrCl4/VAC in the removal of fluoride to obtain drinking water.

This study is concerned with the removal performance of the antibiotic ciprofloxacin (CIP) from synthetic solutions by electrocoagulation (EC), as well as the toxic effects of treated CIP solutions. A response surface analysis (RSA) was applied to search optimal operational parameter values of the pH of solution, electrical current density (ECD), and electrolysis time (ET). The EC efficiency was evaluated by determining the total organic carbon (TOC) and CIP concentration performed by high-performance liquid chromatography. Although the best EC efficiency was attained at pH = 8, ECD = 22.2 A m−2, and ET = 75 min, toxicity and antibacterial tests were performed using Artemia salina cysts and Staphylococcus aureus and Escherichia coli microorganisms in a wide ET range and other pH and ECD values. Increasing optimal pH value (9), along with reducing optimal ECD value (18 A m−2) and regarding low ET values, similar results for the removal of CIP (98%) and TOC (87%) were also attained. Toxicity variation was observed during EC process in synthetic solutions with the lowest antibacterial effects due to CIP and recalcitrant compound residues after 40 min of ET. These results clearly showed that the EC process presents a promising alternative method for the treatment of wastewaters containing high CIP concentrations.

In this study, lead bioaccumulation by the living free-floating aquatic macrophyte Eicchornia crassipes in different hydroponic conditions with variations in phosphorus and lead concentrations was investigated. A set of growth experiments in hydroponic media doped with lead and phosphorus within a wide concentration range was performed for 32 days in a greenhouse. All experiments were carried out with periodic replacement of all nutrients and lead. The concentration of lead and nutrients in biomass was determined by synchrotron radiation-excited total reflection X-ray fluorescence. By increasing the lead concentration in the medium, a reduction in biomass growth was observed, but a higher phosphorus retention in roots and leaves was shown at lower lead concentrations. In addition, an increase in the amount of bioaccumulated lead and phosphorus in roots was observed for higher lead and phosphorus concentrations in the medium, reaching saturation values of 4 mg Pb g(-1) and 7 mg P g(-1), respectively. Four non-structural kinetic models were tested, to represent the bioaccumulation of lead and phosphorus in roots. Pseudo-second order and irreversible kinetic models described the lead bioaccumulation data well, however, an irreversible kinetic model better fitted phosphorus uptake in roots.

In this work, an optimized photo-Fenton process was applied to remove pollutants from tannery industrial effluent (TIE) with its final toxicity level being assessed by a lettuce-seed-based bioassay test. A full 33 factorial design was applied for the optimization of long-term photo-Fenton experiments. The oPtimum conditions of the photo-Fenton process were attained at concentration values of 0.3 g Fe(2+) L(-1) and 20 g H2O2 L(-1) and pH3, for 120 min UV irradiation time. Reactor operating parameter (ROP) effects on the removal of chemical oxygen demand, colour, turbidity, total suspended solids and total volatile solids were evaluated, suggesting that a broad range of ROP values are also suitable to give results very near to those of the photo-Fenton experiments under optimal conditions. Based on the low calculated median lethal dose (LD50) values from a lettuce-seed-based bioassay test, we suggest that recalcitrant substances are present in treated TIE samples. A possible cause of the high toxicity level could partly be attributed to the nitrate concentration, which was not completely abated by the photo-Fenton process. Apart from this, the photo-Fenton process can be used as a part of an industrial effluent treatment system in order to abate high organic pollutant loads.

In this work, the mechanism of the Cr(III) sorption by Salvinia auriculata biosorbent was studied in two stages. To understand the influence of the sorption parameters on the Cr(III) uptake, preliminary tests were performed. First, S. auriculata biomass was separately treated with base and acid solutions. Second, acid and base treatment of samples was performed based on the knowledge data base of our group. It was achieved a higher Cr(III) sorption capacity above 15 mg g-1 as associated to an increase of the micro-pores specific area and biosorbent volume. The obtained kinetic data of raw and treated biosorbents were well described by the intra-particle diffusion model. In this model, Cr(III) adsorption onto treated biomass is progressively improved with appearing of different mass transfer zones from out layer up to micro-porous layers. The equilibrium data of raw biomass were best described by the Langmuir isotherm, whereas the equilibrium data of the treated biomass were best fit by a combination of both Langmuir and Dubinin-Radushkevich isotherms. At low concentrations the adsorption most likely occurred on the outer monolayer, as proposed by the Langmuir model, followed by the adsorption on the micro-porous layers, as validated by the Dubinin-Radushkevich isotherm.

Removal of Cr(VI) species by dried biomass of the aquatic macrophyte Salvinia auriculata was studied in order to understand the involved sorption mechanisms. Kinetic tests were carried out under the conditions such as concentration range of Cr(VI) from 50 to 250 mg L-1 and a temperature of 30 °C. Modification of the biosorbent by the presence of Cr(VI) species was assessed by analysis of its porosity, density and infrared molecular absorption spectrum. A series of experimental approaches involving directed chemical modifications on the biosorbent surface was performed. The main functional groups involved in the sorption mechanisms were identified. The gas sorption analyser was applied and proved that a strong chemical effect of Cr(VI) species on the surface took place, resulting in a leaching organic matter with an obvious and significant increase in the porosity parameters. The intra-particle diffusion model revealed different mass transfer zones into the adsorbent during Cr(VI) removal. New combined Langmuir and Dubinin-Radushkevich isotherm was the best to fit the equilibrium data of Cr(VI) species removal. Finally, Cr(VI) removal was mainly mediated by a redox process where Cr(III) species were formed.

In this work, the improvement on the concentrated grape juice physico-chemical characteristics by using an enzymatic treatment followed by Membrane Separation Process (MSP) has been investigated. By using Novozym 33095(r) and Ultrazym AFP L(r) enzymes varying three operating parameters, the best result on the grape pulp characteristics was attained for the Novozym 33095(r) performed at 35oC, 15 min. and 50 mgL-1. In micro/ultra filtration processes after enzymatic pretreatment, the best performance of the MSP with high permeate flux value and suitable grape juice characteristics was attained using 0.05 mm membrane pore size, 1 bar pressure and 40 oC treatment temperature. When reverse osmosis process is operated at 40 bar and 40oC, high soluble solid and low turbidity values are attained. An enzymatic treatment along with MSP has shown an alternative and efficient grape juice processing system, being possible to extend to other foods. RESUMO Neste trabalho, o melhoramento físico-químico das características do suco de uva concentrado utilizando um tratamento enzimático seguido pelo Processo de Separação de Membranas (PSM) foi investigado. Usando-se as enzimas Novozym (r) 33095 e Ultrazym APPL (r) variando três parâmetros operacionais, o melhor resultado das características da polpa de uva foi obtido pela Novozym 33095 (r) realizada a 35 °C, 15 min. e 50 mgL-1. Nos processos de micro / ultra filtragem depois do pré-tratamento enzimático, o melhor desempenho do PSM com valor do alto fluxo permeado e adequadas características do suco de uva foi alcançado usando membrana com tamanho de poro de 0,05 μm, pressão de 1 bar e temperatura de 40 °C tratamento. Quando o processo de osmose reversa é operado a 40 bar e 40 °C, elevados sólidos solúveis e baixos valores da turbidez são alcançados. Um tratamento enzimático juntamente com PSM mostrou um sistema de processo alternativo e eficiente do suco de uva, podendo ser estendido para outros alimentos.

In this work the analysis of elements concentration in groundwater was performed using the synchrotron radiation total-reflection X-ray fluorescence (SR-TXRF) technique. A set of nine tube-wells with serious risk of contamination was chosen to monitor the mean concentration of elements in groundwater from the North Serra Geral aquifer in Santa Helena, Brazil, during 1 year. Element concentrations were determined applying a SR-TXRF methodology. The accuracy of SR-TXRF technique was validated by analysis of a certified reference material. As the groundwater composition in the North Serra Geral aquifer showed heterogeneity in the spatial distribution of eight major elements, a hierarchical clustering to the data was performed. By a similarity in their compositions, two of the nine wells were grouped in a first cluster, while the other seven were grouped in a second cluster. Calcium was the major element in all wells, with higher Ca concentration in the second cluster than in the first cluster. However, concentrations of Ti, V, Cr in the first cluster are slightly higher than those in the second cluster. The findings of this study within a monitoring program of tube-wells could provide a useful assessment of controls over groundwater composition and support management at regional level.

The treatment of tannery industrial effluent (TIE) by integrating the widely used photo-Fenton and electrocoagulation (EC) processes was investigated. The optimization of the photo-Fenton process by using solar irradiation was made performing a full 3 3 factorial experimental design. An irradiation time of 120 min for the photo-Fenton reaction was more favorable to pollutant removal in acidic medium using Fe 2+ concentrations ranging from 0.4 to 0.5 g L −1 and H 2 O 2 concentrations ranging from 15 to 30 g L −1 . Nonetheless, a reduction in sludge production and a minimum residual content of hydrogen peroxide were attained within 540 min of irradiation time, with 0.4 g L −1 Fe 2+ and 15 g L −1 H 2 O 2 initial concentrations, with almost the same efficiency of COD, color, and turbidity removal obtained under the optimal experimental conditions. When the pretreated TIE samples were submitted to an EC process, the results of inorganic pollutants removal were better than with the conventional method (use of a combination of filtration, chemical coagulation, and sedimentation processes). In addition, the application of the integrated photo-Fenton and EC process for TIE treatment is cheaper than the conventional one. All the results showed that the integrated photo-Fenton and EC process could be applied as an efficient low-cost alternative treatment for the removal of organic and inorganic pollutants from tannery industrial effluent with a low environmental impact.

An electrocoagulation laboratory scale system was studied for the removal of inorganic pollutants from a mixture of galvanic process-based by-products. Response surface methodology based on a five-level, four-variable central composite rotatable design was employed for optimization with respect to four important variables—reaction time, agitation velocity, current density, and pH. The electrocoagulation process response was evaluated on the basis of chemical oxygen demand (COD), turbidity, total suspended solid, and element concentration values. Interaction effects between reactor operating variables and response variables were evaluated by using 3-D response surface analysis Second-order models were validated by ANOVA. Predicted yields were in a good agreement with the experimental ones. The reactor optimal performance was achieved at 35 min reaction time, 170 rpm agitation velocity, 97.7 Am−2 current density, and 6.5 initial pH. Under these conditions 100% color and turbidity, 90% COD and total suspende...

In this work, reuse water networks have been modeled and optimized by the application of the Particle Swarm Optimization (PSO) method. From a built-in superstructure, which represents the whole possible configurations of the reuse water networks, a modified PSO method was proposed in order to lead with both discrete- and continuous-type variables in Non-Linear Programming (NLP) and Mixed Integer Non-Linear Programming (MINLP) models that represent water allocation problems. By introducing pinch analysis concepts, the improved PSO method has shown excellent performance in the optimality of reuse water network synthesis based on the minimization of freshwater flow rate, number of interconnections and annual total cost. PSO results were compared with those of the General Algebric Modeling System (GAMS) for all criteria, showing the flexibility and efficiency of the metaheuristic approach in solving water network reuse synthesis problems.

In this work, the sorption capacity behavior of copper and cadmium divalent ions in single and binary systems has been investigated. Batch metal sorption experiments to obtain the kinetic and equilibrium data for the dry biomass of the Eichhornia crassipes species were performed under controlled temperature, constant shaking and pH 5. An equilibrium time of 60 min was achieved for both Cu(II) and Cd(II) ions in mono-component system as well as in binary one. It was found that the overall adsorption data were best described by the pseudo second-order kinetic model. Six adsorption isotherms have been tested to fit the mono-component equilibrium data, obtaining the best description by the Langmuir-type one. A modified extended-to-multi-component Langmuir-type isotherm model was applied to predict the binary adsorption data and its adjustable parameters were estimated by the PSO method. Finally, the results have shown that the affinity of each metal ion onto the E. crassipes surface is influenced by the presence of the other one.

This study is focused on the analysis of an accumulation of inorganic elements in muscles, liver and gonad of seven fish species from São Francisco River located in the Paraná state of Brazil. Concentrations of the elements were determined using the SR-TXRF technique. In the muscles of fish species, negative length dependent relationships were observed for chromium and zinc ion absorption. The obtained results showed that accumulated Cr ions values are above the limits defined in the Brazilian legislative norm on food.

This work presents a mathematical model for soybean oil extraction in a belt extractor with miscella recirculation. The mathematical model consists of partial differential and algebraic equations and it takes into account the extractor dimension and the physical properties of the solid and miscella. Experimental data collected in an industrial process in Stead State were used to check the model validity. The model was solved using the Finite Difference Method in a computational routine developed in Maple™ and it was compared with the Method of Ideal Stages. The results are coherent and consistent with the extraction phenomena and they can be used to evaluate the influence of several parameters and to obtain the soybean oil concentration profile in any of the phases and parts of the extractor, either in vertical or horizontal arrangement.

In this work, orange bagasse has been used as an alternative adsorbent for removal of reactive blue 5G dye from an aqueous solution. The influence of the dye solution pH, the biosorbent drying, the dye solution temperature and biosorbent grain size was studied in batch systems, in order to improve the biosorption kinetics and the experimental equilibrium conditions. Batch kinetic experiments were carried out with different dye concentrations at two temperatures. The biosorption kinetic data were well fitted by both pseudo-first and second order models. The equilibrium adsorption data were interpreted by applying widely the isotherm models and a set of six BET isotherm-added-to other ones and their adjustable parameters were determined by the PSO method. The isotherm models with s-shaped behavior, such as the Langmuir–BET combined isotherm, have described satisfactorily the equilibrium data, suggesting that the dye removal is based on an adsorption process of multi-layers onto the orange bagasse.

In this work, the behavior of cationic-exchange resin, activated carbon, and non-living aquatic macrophytes biomasses on the Cr(VI) and Cr(III) uptake and Cr(VI) reduction was investigated. The high-resolution X-ray fluorescence (HR-XRF) technique was used to study the adsorption process, as well as to study Cr(VI) reduction and removal from metal solutions. Batch Cr ions sorption experiments at pH 3.5 were carried out in order to speciate 3d-transition metal onto the surface of these types of adsorbents by a Kβ spectra analysis. Cr-Kβ satellite lines have been characterized for all Kβ spectra of Cr ions onto treated samples and reference material. Based on their energy position and intensity of Cr-Kβ satellite lines as well as their related to reference material shift energy, activated carbon and non-living aquatic macrophytes roots were found to act mainly as good adsorbents, first reducing Cr(VI) to Cr(III) and then followed by a Cr(III) adsorption. Although cationic-exchange resin was treated with Cr(VI) solution, no evidence of any Cr-Kβ spectral satellite lines was shown in it, suggesting that Cr(VI) was not removed in a cationic-exchange process. Evidence of reduction of hexavalent chromium by adsorbent materials was assessed by Kβ spectral lines analysis.

The biodegradation kinetics of BTEX (benzene, toluene, ethylbenzene and xylene isomers) compounds were studied individually and as mixtures by using models with different levels of sophistication. In order to evaluate the performances of the unstructured models we used experimental data from literature. The system description was based on the material balances of key components for batch operations, where Monod and Andrews models were applied for the biodegradation of individual substrates. To simulate the biodegradation kinetics of substrate mixtures, models of competitive, noncompetitive and uncompetitive inhibition were applied along with the sum kinetics with interaction parameters (SKIP) models. The kinetic parameters were estimated via a global search method known as Particle Swarm Optimization (PSO). The main result of this study shows that the sophisticated biodegradation kinetics of BTEX mixtures can be successfully described by applying a SKIP model, with the main advantage being the consideration of the substrate interactions.

O bagaço de laranja úmido pode ser utilizado como adsorvente. A atividade de água é uma das variáveis que mais afetam o processo fermentativo e, consequentemente, o armazenamento deste material, razão pela qual, este trabalho teve como objetivo, a determinação das isotermas de sorção do bagaço de laranja nas temperaturas de 25, 35 e 50 °C, de modo a correlacionar a umidade com a atividade de água. Os teores de umidade de equilíbrio foram determinados pelo método estático utilizando-se soluções de sais para uma faixa de umidade relativa de 10 a 80%. Os modelos de Henderson, Chung-Pfost, Henderson Modificado, Halsey, Luikov e Motta Lima, foram ajustados aos dados experimentais, em que os resultados mostraram que as isotermas apresentaram forma sigmoidal e os modelos de Luikov e Halsey foram os que melhor representaram os dados de equilíbrio do bagaço de laranja. Wet bagasse can be used as an adsorbent in effluent treatment process. However, before its use a previous drying is necessary. The water activity is an important parameter that affects the fermentation process, and thus its determination becomes most important in order to store this adsorbent. Thus, the objective of this work is to determine the sorption isotherms of orange bagasse at 25, 35 and 50 °C temperatures in order to correlate the moisture with a water activity. The equilibrium moisture content was determined by the static method using salts solution for a 10-80% relative humidity range. The following models were fitted to the experimental data: Henderson, Chung-Pfost, Modified Henderson, Halsey, Luikov and Motta Lima. All models results followed a sigmodal-type function. The equilibrium data for the orange bagasse were better represented by the Luikov and Halsey models.

The region of Toledo River, Parana, Brazil is characterized by intense anthropogenic activities. Hence, metal concentrations and physical–chemical parameters of Toledo River water were determined in order to complete an environmental evaluation catalog. Samples were collected monthly during one year period at seven different sites from the source down the river mouth, physical–chemical variables were analyzed, and major metallic ions were measured. Metal analysis was performed by using the synchrotron radiation total reflection X-ray fluorescence technique. A statistical analysis was applied to evaluate the reliability of experimental data. The analysis of obtained results have shown that a strong correlation between physical–chemical parameters existed among sites 1 and 7, suggesting that organic pollutants were mainly responsible for decreasing the Toledo River water quality.

Neste trabalho, foi estudada a capacidade de biossorção da macrófita aquática Egeria densa seca na remoção do íon zinco. Os testes cinético e de equilíbrio foram realizados em sistema de batelada com temperatura, agitação e pH controlados. Os resultados obtidos na cinética de biossorção demonstram uma rápida remoção do zinco (II), com tempo de equilíbrio em torno de 45 minutos e taxa de remoção superior a 70%. O modelo cinético de pseudo-segunda ordem foi o que melhor representou os dados experimentais. No estudo do equilíbrio, verificou-se que o modelo de Langmuir ajustou-se melhor aos dados experimentais, com capacidade máxima de sorção de 0,92 mequiv g-1 e razão entre as taxas de sorção e dessorção de 0,829 L g-1 em pH 5. Os resultados obtidos demonstram que a macrófita E. densa tem potencial para ser utilizada em sistemas de tratamento de efluentes industriais.In this paper, the removal potential on Zn ion by macrophyte Egeria densa has been studied. The influence of the metal solution pH, the plant drying and the metal solution temperature, and biosorbent grain size was previously studied in batch systems. Adsorption kinetic and equilibrium experiments of metals onto E. densa were performed under controlled temperature and permanent shaking. In adsorption kinetic tests for Zn (II) the equilibrium time was around 45 min. The biosorption kinetic data were well fitted by a pseudo-second order model. The equilibrium data at pH 5 were described a rather better by the Langmuir isotherm than the Freundlich one, with an adsorption rate and maximum metal content values of 0,829L g-1and 0,92 mequiv g-1, respectively, for Langmuir model. The macrophytes E. densa could be used as biosorbent material in industrial effluent treatment system.

In this study the pollutant removal from a textile dyeing wastewater has been investigated by using the electro-coagulation technique with iron electrodes. In order to obtain optimal values of the system state variables, a 33 full factorial experimental design was applied. The electro-coagulation (EC) process response was evaluated on the basis of COD removal and decolourisation values. The electrolysis time and density current were statistically significant for the COD removal and decolourisation. Based on the lettuce seeds (Lactuca sativa) and brine shrimp (Artemia salina), the lowest toxicity level was achieved in 5 min of electrolysis time. Due to the remaining high toxicity level above 30 min of electrolysis time, the EC process is not adequate to be used in a single effluent treatment, suggesting that this electrochemical process of up to 5 min could be used as part of a complete effluent treatment system.

An electro-coagulation laboratory scale system using aluminium plates electrodes was studied for the removal of organic and inorganic pollutants as a by-product from leather finishing industrial process. A fractional factorial 23 experimental design was applied in order to obtain optimal values of the system state variables. The electro-coagulation (EC) process efficiency was based on the chemical oxygen demand (COD), turbidity, total suspended solid, total fixed solid, total volatile solid, and chemical element concentration values. Analysis of variance (ANOVA) for final pH, total fixed solid (TFS), turbidity and Ca concentration have confirmed the predicted models by the experimental design within a 95% confidence level. The reactor working conditions close to real effluent pH (7.6) and electrolysis time in the range 30–45 min were enough to achieve the cost effective reduction factors of organic and inorganic pollutants' concentrations. An appreciable improvement in COD removal efficiency was obtained for electro-coagulation treatment. Finally, the technical-economical analysis results have clearly shown that the electro-coagulation method is very promising for industrial application.

Neste trabalho foi realizada uma avaliação das propriedades reológicas de trigo armazenado no período de 5 meses, objetivando dar subsídios para que as aquisições ou o uso do trigo possam ser feitos na colheita ou se necessitam de um tempo de repouso, para evolução das propriedades reológicas. Foram realizadas análises com 4 variedades de trigo Coodetec CD 104, CD 112, CD 200133 e CD 200213. O intervalo entre as análises foi de 30 dias, iniciando na colheita até 150 dias de armazenamento. Foram analisados a Alveografia (força geral do glúten, tenacidade e extensibilidade da massa), o Teor de Glúten (Glúten úmido e seco) e o Número de Queda. Os resultados obtidos mostraram que, no período, não houve evolução na força do glúten e no número de queda. Pequenas variações que ocorreram nas outras análises, como tenacidade e extensibilidade, não são significativas do ponto de vista da indústria moageira. Desta forma, os resultados obtidos mostram que não existe a necessidade de retardar a aquisição e o uso do trigo na colheita em relação às propriedades reológicas, reduzindo desta forma o tempo e o custo de armazenamento.The objective of this work was to evaluate the rheological properties of 5 months of storage of wheat and investigate how the method of storage influences the use of wheat and its rheological properties. The assays were conducted with 4 variations of wheat: CoodeteC - CD 104, CD 112, CD 200133 and CD 200213. The time interval between the assays was 30 days and the storage time was up to 150 days after harvest. Alveogram parameters (general gluten force, tenacity, and extensibility of mass), the humid and dried gluten, and falling number were evaluated. The obtained results indicated that during the chosen storage period the gluten force and falling number did not change. The other assays showed small variations, for example on tenacity and extensibility, but this fact is not significant from the industrial point of view. Hence, the obtained results demonstrated that there is no need to delay the acquisition and the use of wheat upon harvest based on its rheological properties since this type of storage increases its cost.

An electrocoagulation laboratory scale system was studied for the removal of organic and inorganic pollutants from a wastewater of leather finishing industrial process. In order to obtain optimal values of the system state variables, a fractional factorial 2 3 experimental design was applied. The electrocoagulation process response was evaluated on the basis of chemical oxygen demand (COD), turbidity, total suspended solid, total volatile solid, and elements concentration values. The interactions between initial pH and electrolysis time, as well as between initial pH and current density were significant only for the total chromium removal. The reactor working conditions close to natural effluent pH and electrolysis time in the range of 30–45 min were enough to achieve the cost-effective reduction of COD, turbidity and chromium concentrations. The electrocoagulation method has shown similar pollutant removal efficiencies when compared with the conventional one and can be used successfully for industrial applications. Based on its low operational cost, the electrocoagulation method could be recommended instead of the conventional one. © 2009 Elsevier B.V. All rights reserved.

In the present work, the lead phytoaccumulation by living free floating aquatic macrophytes Salvinia auriculata was investigated in a greenhouse. These plants were grown in lead-doped hydroponic solutions forming, as a function of time, six collections of nutrient media, roots and leaves of plants from a batch system. The synchrotron X-ray radiation fluorescence technique was used in order to determine element concentrations in the nutrient media, dry roots and aerial parts of plant. The aquatic plant-based lead removal data were described by using a non-structural kinetic model. According to the experimental data, both adsorption and bioaccumulation mechanism are present and a competition between the phosphorus macronutrient and lead for plant growth was observed, when great concentration of lead in roots is present. The non-structural kinetic models have shown good agreement with the lead uptake experimental data in all the investigated cases. The results of living macrophytes S. auriculata-based-metal bioaccumulation kinetic parameters can be used in artificial wetlands to predict the heavy metal removal dynamics from wastewaters.