Browsing by Author "Salazar-Gonzalez, Ricardo"

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    Assessing the photo-activation efficiency of aminopolycarboxylate iron complex mixtures for effective sulfamethoxazole degradation in a pilot-scale UVA-LED photoreactor
    (2024) Herrera-Munoz, Jose; Cabrera-Reina, Alejandro; Salazar-Gonzalez, Ricardo; Miralles-Cuevas, Sara
    This study focused on the degradation of antibiotic sulfamethoxazole (SMX), through the UVA-LED photo-activation of aminopolycarboxylate-based iron complexes in a pilot-scale photoreactor. Fe3+-EDDS, Fe3+-NTA, and a combination of both complexes Fe3+-EDDS and Fe3+-NTA were studied in simulated tap water (TW) and simulated secondary effluent (SE) from a municipal wastewater treatment plant (MWWTP). In TW, 40% SMX degradation was reached after 60 min, with different concentration profiles due to absorption characteristics of each complex. Combining Fe3+-EDDS and Fe3+-NTA an initial rapid SMX degradation was observed followed by a slower phase, improving SMX degradation with respect to each complex separately. In SE and despite presenting similar kinetics, SMX degradation was lower than in TW, due to the presence of organic matter in the water matrix. Moreover, the Fe3+-EDDS and Fe3+-NTA mixture improved SMX degradation with increasing iron concentration. This improvement was attributed to reduced dissolved organic carbon (DOC) from NTA and the lower molar absorption coefficient of Fe3+-NTA. Higher EDDS ratios led to faster complex degradation but did not significantly enhance SMX removal. Conversely, higher NTA ratios reduced SMX degradation. In summary, this study revealed a synergistic effect between Fe3+-EDDS and Fe3+-NTA in SMX degradation. Considering the cost difference between EDDS and NTA, using both compounds offers technical and economic advantages. All treatments reduced chronic toxicity in Selenastrum capricornutum.
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    Assessment of contaminants of emerging concern and antibiotic resistance genes in the Mapocho River (Chile): A comprehensive study on water quality and municipal wastewater impact
    (2024) Herrera-Munoz, Jose; Ibanez, Maria; Calzadilla, Wendy; Cabrera-Reina, Alejandro; Garcia, Veronica; Salazar-Gonzalez, Ricardo; Hernandez, Felix; Campos-Manas, Marina; Miralles-Cuevas, Sara
    The primary objective of this study was to evaluate the persistence and elimination of Contaminants of Emerging Concern (CECs) in municipal wastewater treatment plants (MWWTPs) and their presence in the Mapocho River within the metropolitan area of Santiago, Chile. The use of advanced analytical techniques, based on liquid chromatography coupled to both low and high-resolution mass spectrometry, allowed a comprehensive overview on the presence of CECs in samples. Additionally, a preliminary assessment of the microbiological aspects aimed to determine the presence of indicator microorganisms of fecal contamination, such as Escherichia coli and total coliforms was conducted. Furthermore, a qualitative assessment of Antibiotic Resistant Genes (ARGs) was performed. No CECs were detected upstream to the MWWTPs. However, the results from various wastewater samples (influent, secondary, and tertiary effluents) revealed significant diversity, with 73 CECs detected alongside prevalent ARGs including sult, , sulftt, , qnrB, , and blaTEM. . The presence of CECs and ARGs downstream of the MWWTP in the Mapocho River was mainly attributed to effluent discharge. On the other hand, typical values for a healthy river and a MWWTP with a final disinfection stage were found in terms of fecal contamination. Consequently, the imperative for developing tertiary or quaternary treatments capable of degrading CECs and ARGs to minimize environmental impact is underscored. These findings hold public health significance, offering insights into potential risks and influencing future legislative measures in Chile.
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    Degradation of dairy wastewater using sustainable nanotechnology composed of a-Fe2O3/TiO2 rod-shaped material and photocatalytic process: a complementary treatment approach for industrial wastewater
    (2024) Espinoza-Villalobos, Nicole; Rojas, Susana; Barrientos, Lorena; Salazar-Gonzalez, Ricardo; Luna, Damari; Flores, Caetano; Escalona, Nestor
    BACKGROUND: High water consumption and the toxic pollutants found in industrial wastewater are key challenges in achieving a more sustainable development. In this sense, it is crucial to develop sustainable ways to reduce the organic pollutants found in wastewater and to promote its reuse.
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    Elimination of sulfamethoxazole by anodic oxidation using mixed metal oxide anodes
    (2023) Lauzurique, Yeney; Miralles-Cuevas, Sara; Godoy, Mariel; Sepulveda, Pamela; Bollo, Soledad; Cabrera-Reina, Alejandro; Huilinir, Cesar; Malato, Sixto; Oller, Isabel; Salazar-Gonzalez, Ricardo
    The degradation of sulfamethoxazole (SMX) was studied by anodic oxidation (AO) process using mixed metal oxide (MMO) electrodes with different Ru/Ir ratios. Each electrode was characterized morphological and electrochemically. The electrolyzes were performed in NaCl and Na2SO4 applying two current densities (10 and 50 mA cm-2). The electrode with the highest composition of Ir, Ru/Ir (30/70), showed greater SMX degradation and generation of oxidizing species and was used to treat the antibiotic by AO and AO assisted by solar energy in natural water and actual municipal wastewater effluents.The efficiency in SMX degradation depends on the type of electrode used (MMO) and electrolytic medium. All MMO electrodes, reached almost total degradation of SMX in chloride medium. However, 60 % degradation of SMX in sulfate medium was achieved with anode with lower Ru/Ir ratio. Additionally, degradation of SMX in complex matrices can be successfully carried out by solar-assisted AO and AO processes, without the need to adjust the pH, at room temperature and using anode with lower Ru/Ir ratio. Finally, the AO process assisted by solar energy reduced electrolysis times and the cell's potential, leading to lower energy consumption.
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    Enhancing industrial swine slaughterhouse wastewater treatment: Optimization of electrocoagulation technique and operating mode
    (2024) Sandoval, Miguel A.; Coreno, Oscar; Garcia, Veronica; Salazar-Gonzalez, Ricardo
    In this study, industrial swine slaughterhouse effluents were treated by an electrocoagulation process (EC) with aluminum and iron electrodes. Batch and semicontinuous operation were performed. EC tests were carried out in batch operating mode for 2.5 h using fixed current densities (j = 10, 20, and 30 mA cm-2) in sulfate and chloride media. At the laboratory scale, higher TOC removal efficiencies were observed using aluminum electrodes at 20 mA cm-2 without the addition of a supporting electrolyte (82.7%). However, the EC process with Fe electrodes consumed 43.6% less energy.After the best operating parameters were found at the laboratory scale, the process was tested as a semi -continuous prepilot process using a filter-press FM01-LC-type electrochemical reactor equipped with flat plate aluminum electrodes. In this stage, current densities and mean linear flow rates were assessed. The highest TOC removal efficiency of 72.7% (i.e., residual TOC concentration of 85.18 mg L-1) in the semicontinuous process was achieved by the application of j = 25 mA cm-2 and ur = 0.64 cm s- 1 with an energy consumption of 19.80 kW h m- 3. The residual COD and TP concentrations met the international standard limits. Moreover, complete decoloration and disinfection were accomplished. EDXRF, SEM, EDAX, XRD, and FTIR analyses indicated that pollutants were removed by adsorption on aluminum/iron hydroxides/oxyhydroxides.
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    Evaluation of the anaerobic digestion of winery wastewater: Effect of fly ash in anaerobic sequencing batch reactor
    (2023) Lauzurique, Yeney; Meza, Ariel; Huilinir, Cesar; Salazar-Gonzalez, Ricardo; Vargas-Morales, Gustavo
    The addition of fly ash (FA) to an anaerobic reactor has been studied mainly in batch tests. Nevertheless, the FA effect on the continuous operation of an anaerobic bioreactor has not been addressed. Therefore, the present work shows the effect of FA on the continuous operation of anaerobic sequencing reactors (ASBRs) treating winery wastewater. Two ASBRs were used and operated continuously for 302 days under mesophilic conditions with a hydraulic retention time (HRT) of 3 days. The effect of the organic loading rate (ORL) on the operation was investigated for 204 days. After that, to evaluate the effect of FA as an anaerobic digestion (AD) enhancer, one of the reactors was dosed with 25 mg L-1 of FA for 98 days. The FA dosages allowed an increase in methane production and organic matter removal by 75% and 42%, respectively, concerning the system without FA. Furthermore, the importance of FA in the process was demonstrated by obtaining a yield of 334 NmL CH4 COD removed-1. This result represented a 12% increase compared to the yield previously obtained in the same reactor before adding the FA. Additionally, acetic acid and propionic acid were the predominant volatile fatty acids (VFAs) in the process. Finally, the metals present in the digested sludge after FA addition did not exceed the limits allowed by Chilean legislation.
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    Fast simultaneous electrochemical detection of Bisphenol-A and Bisphenol-S in urban wastewater using a graphene oxide-iron nanoparticles hybrid sensor
    (2023) Pina, Samuel; Sepulveda, Pamela; Garcia-Garcia, Alejandra; Moreno-Barcenas, Alejandra; Toledo-Neira, Carla; Salazar-Gonzalez, Ricardo
    In this work, a novel and sensitive electrochemical sensor was developed for the simultaneous determination of low concentration levels of Bisphenol-A (BPA) and Bisphenol-S (BPS) in a secondary effluent from a wastewater treatment plant and surface water. The sensor design involved the utilization of a glassy carbon electrode that was modified with hybrid iron nanoparticles and a nanostructure of graphene oxide. The synthesized material displayed a stable heterostructure, facilitating efficient electronic transfer and exhibiting impressive electro-catalytic capacity. Furthermore, the sensor successfully detected anodic signals of BPA and BPS with a peak separation of 0.28 V, confirming its excellent performance. For method optimization, a chemometric tool based on a Central Composite Face (CCF) design response surface was employed. The optimized conditions yielded an analytical curve with a linear range of 15.0 to 120.0 mu mol L-1 for BPA, represented by the equation Iap (mu A)=-0.088 + 0.044 (mu A L mu mol-1) [cBPA], and 20.0 to 70.0 mu mol L-1 for BPS, represented by the equation Iap (mu A)=-0.367 + 0.025 (mu A L mu mol-1) [cBPS]. The detection and quantification limits for BPA were established at 12.05 and 36.51 mu mol L-1, respectively. Similarly, for BPS, the corresponding values were determined to be 11.63 and 35.24 mu mol L-1. The electrochemical method developed was validated by comparing it with the high-performance liquid chromatography coupled to diode array detector (HPLC-DAD) technique. Notably, the electrochemical method demonstrated to be successful in the simultaneous detection and quantification of BPA and BPS in a secondary effluent and surface water.
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    hr Hydrophobic deep eutectic solvent as extractant phase for determining six carcinogenic polycyclic aromatic hydrocarbons in tea and coffee infusion samples
    (2023) Mesias-Salazar, Angela; Rebolledo-Robles, Kevin; Salazar-Gonzalez, Ricardo; Bravo, Manuel A.; Lucena, Rafael; Toledo-Neira, Carla
    In this work, an analytical methodology was developed for determining polycyclic aromatic hydrocarbons (PAHs) in tea and coffee samples. The new analytical methodology uses a hydrophobic deep eutectic solvent (DES), consisting of a thymol and lidocaine mixture, for the extraction of the analytes under dispersive liquid-liquid microextraction. The extraction procedure was optimized considering several variables (extraction phase composition, sample volume, vortexing and centrifugation time). Under optimum conditions, an using ultrahigh-performance liquid chromatography with fluorescence detection as instrumental technique, the limits of detection were 39 and 53 ng & BULL;L-1 in tea and coffee samples, respectively. The precision expressed as relative standard deviation was better than 6.3 %.The relative recoveries were in the 60.7-85.2 % interval. The proposed method was successfully applied to the analysis of tea and coffee samples. The levels found for the six carcinogenic PAHs are between 10-45 & mu;g & BULL;L-1 for tea infusions and 6-31 & mu;g & BULL;L-1 for coffee infusions. The methodology is defined as an excellent green method with a score of 80 using the analytical Eco-scale.
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    Removal of Ibuprofen and Diclofenac in Batch Nitrifying Reactors: Effect of Natural Zeolite on the Process
    (2023) Escobar, Jenny; Hernandez, Leslie; Gonzalez, Jorge Leiva; Salazar-Gonzalez, Ricardo; Calzadilla, Wendy; Guerrero, Lorna; Escalona, Nestor; Huilinir, Cesar
    Ibuprofen (IBP) and diclofenac (DFC) are two of the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs) to treat inflammation and pain. However, they can impact the environment if not treated adequately before discharge into waterways. Biodegradation through the nitrification process is an alternative to reducing the concentration of these micropollutants (MPs) in wastewater. Thus, this work aimed to evaluate the effect of natural zeolite on IBP and DFC removal in a nitrifying batch reactor. Mini-reactors were set up with 90 mL of inoculum and 110 mL of synthetic wastewater with a concentration of 25 mg total ammonia nitrogen TAN/L, at 25 & DEG;C and 1 vvm (volume of air/volume liquid & BULL;min) of aeration. Two conditions were tested: high concentrations (IBP = 700 & mu;g/L, DFC = 100 & mu;g/L) and low concentrations (IBP = 30 & mu;g/L, DFC = 20 & mu;g/L). The research used a concentration of 5 g/L of the natural zeolite. Results indicated that the zeolite negatively affected the nitrification rate. At high MPs concentration, the natural zeolite negatively affects the removal of IBP and DFC, where biodegradation and sorption are the mechanisms that eliminate both NSAIDs. Conversely, at low DFC and IBP concentrations, the natural zeolite improves the removal of IBP and DFC, wherein biodegradation is the primary removal mechanism.
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    Use of copper sheet in a solar photo-Fenton-like process applied in the treatment of landfill leachate
    (2023) Poblete, Rodrigo; Rodriguez, Carlos Anibal; Carrasco, Claudia; Herrera, Jose; Salazar-Gonzalez, Ricardo
    It is known that copper can be used as catalyst in photo-Fenton-like process; however, there is a lack of information related with its use in the treatment of landfill leachate (LL) in solar photo-Fenton-like processes. Here, we studied the effect of the mass of a copper sheet, the pH of the solution, and the concentration of LL in the removal of the organic matter present in this water. Before the reaction with landfill leachate, the copper sheet used in the reaction was constituted by Cu+ and Cu2O, respectively. The results showed that in a volume of 0.5 L of a pretreated LL, the higher removal of organic matter resulted using a mass of 2.7 g of the copper sheet, a pH of solution of 5, and a concentration of LL of a 10%, obtaining a final value of C/C-0 of chemical oxygen demand (COD) of 0.34, 0.54, 0.66, and 0.84 for concentrations of 25%, 50%, 75%, and 100%, respectively, and 0.0041, 0.0042, 0.0043, and 0.016 for concentration of 25%, 50%, 75%, and 100%, respectively, of C/C-0 of humic acids. The photolysis on LL at its natural pH using solar UV removes very little humic acid and COD, going from 9.4 to 8.5 and 7.7 Abs(254) for photolysis and UV + H2O2, obtaining 8.6 and 17.6% of removal, respectively, and 2.01 and 13.04% removal of COD, respectively. Copper sheet applied under Fenton-like conditions results in 65.9% removal and an increase of 0.2% for humic acid and COD, respectively. Removal using only H2O2 for Abs(254) and COD was 11.95 and 4.3%, respectively. Raw LL produced a 29.1% inhibition of the biological activated sludge rate after the adjustment to pH 7 and the final process of inhibition was 0.23%.