Synthetic Effluent Research Articles

Biofunctional Magnetic Carbon Nanohybrid for Fast Removal of Methyl Blue from Synthetic Laboratory Effluent.

The contamination of aquatic systems by industrial dyes, particularly methylene blue (MB), presents a significant environmental challenge due to their chemical stability and toxicity. In this study, the development and application of a novel magnetic nanohybrid comprising multiwall carbon nanotubes (MWCNTs) functionalized with maghemite (γ-Fe2O3) nanoparticles biosynthesized using Eucalyptus globulus extract (denoted MWNT-NPE) is reported. The material was thoroughly characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Vibrating Sample Magnetometer (VSM), and Fourier-Transform Infrared (FTIR) techniques, revealing high crystallinity, mesoporosity, and superparamagnetic behavior. The MWNT-NPE exhibited exceptional MB adsorption performance under optimized conditions (pH 6, 0.8 g L-1 dose, 40 min equilibrium), achieving a maximum adsorption capacity of 92.9 mg g-1. Kinetic analysis indicated chemisorption and physisorption regimes depending on MB concentration, with the pseudo-second-order and Freundlich isotherm models providing the best fits of experimental data. FTIR spectroscopy demonstrated that the removal mechanism involves π-π stacking, hydrogen bonding, and electrostatic interactions between MB molecules and the composite's surface functional groups. Notably, the magnetic nanohybrid retained over 98% removal efficiency across five regeneration cycles and successfully removed MB from synthetic effluents with efficiencies exceeding 91%. These findings highlight the synergistic adsorption and magnetic recovery capabilities of the bio-functionalized hybrid system, presenting a sustainable, reusable, and scalable solution for industrial dye remediation.

Influence of support medium height on the optimization of performance of an Upflow Anaerobic Hybrid Reactor (UAHB) treating synthetic wastewater

ABSTRACT The support media of upflow anaerobic hybrid reactors (UAHB) facilitates the formation and retention of microbial biofilm and the contact between the influent and microorganisms. Previous studies demonstrated the importance of support media height (SMH) to organic matter removal; however, the influence of this parameter in the UAHB reactor performance under varying conditions is still a gap. The Central Composite Design (CCD) method was applied to optimize the removal of organic matter by varying the cross-sectional area and height of the reactor based on 42 studies. The modelling indicated 72–87% COD removal efficiencies with 0.007 m2 cross-sectional area and 0.75 m height, with 5.5 L total volume. Thus, three pilot-scale UAHB reactors, filled with Corrugated Polyvinyl Chloride (PVC) rings at different heights (6, 15, and 24 cm), were operated with a hydraulic retention time of 10 h, treating synthetic effluent with a COD of 490 mgO2 L−1. Unlike previous studies, this study evaluated identical UAHBs operating in parallel under controlled conditions. The UAHB reactors presented stability, buffering capacity, and neutral pH during the operation. The reactor with higher SMH (24 cm) achieved higher removal efficiencies of turbidity (90%), COD (72.6%), and TS (63%). Variations in SMH affected reactor performance, as corroborated by the negative and ‘very strong’ correlation for turbidity, COD, and TS and a ‘moderate’ correlation for fixed and volatile solids. The novelty of this study lies in its comprehensive assessment of how varying SMH affects UAHB reactor performance, guiding future advancements in its design for efficient wastewater treatment.

Comparing Operational Approaches (Spectrophotometric, Electroanalytic and Chromatographic) to Quantify the Concentration of Emerging Contaminants: The Limit of Detection, the Uncertainty of Measurement, Applicability and Open Problems

In this study, a boron-doped diamond (BDD) sensor was used to study the electroanalytical behavior of emerging contaminants (ECs), such as caffeine, paracetamol and methyl orange. BDD shows strong resolving power for the superimposed voltammetric response of ECs in well-resolved peaks with increased peak current. Differential pulse voltammetry, which is an electroanalytical technique, was compared with two reference techniques including absorption spectrophotometry in the UV-vis region and high-performance liquid chromatography (HPLC) in the detection and quantification of ECs. The results obtained were satisfactory, as the complete removal of ECs was achieved in all applied processes. The detection limits were 0.69 mg L−1, 0.84 mg L−1 and 0.46 mg L−1 for CAF, PAR and MO, respectively. The comparison of electroanalysis results with those obtained by UV-vis and HPLC established and confirmed the potential applicability of the technique for determining CAF, PAR and MO analytes in synthetic effluents and environmental water samples (tap water, groundwater and lagoon water). The electrochemical approach can therefore be highlighted for its low consumption of reagents, ease of operation, time of analysis and excellent precision and accuracy, because these are characteristics that enable the use of this technique as another means of determining analytes in effluents.

Adsorption of Sr2+ from Synthetic Waste Effluents Using Taiwan Zhi-Shin Bentonite.

This study investigated strontium (Sr2+) adsorption by Taiwan Zhi-Shin bentonite (cation exchange capacity (CEC): 80-86 meq 100 g-1) using Sr(NO3)2-simulated nuclear waste. Kinetic analysis revealed pseudo-second-order adsorption kinetics, achieving 95% Sr2+ removal within 5 min at pH 9. Isothermal studies showed a maximum capacity of 0.28 mmol g-1 (56 meq 100 g-1) at 15 mmol L-1 Sr2+, accounting for 65-70% CEC and fitting the Freundlich model. Cation exchange was the dominant mechanism (84% contribution), driven by Sr2+ displacing interlayer Ca2+. Alkaline conditions (pH > 9) enhanced adsorption through improved surface charge and electrostatic attraction. Thermodynamic studies demonstrated temperature-dependent behavior: increasing temperature reduced adsorption at 0.01 mM Sr2+ but increased efficiency at 10 mM. Na+ addition suppressed adsorption, aligning with cation exchange mechanisms. Molecular dynamics simulations identified hydrated Ca2+-Sr2+ water bridges interacting with bentonite via hydrogen-bonding networks. The material exhibits rapid kinetics (5 min equilibrium), alkaline pH optimization, and resistance to ion interference, making it suitable for emergency Sr2+ treatment. It shows promise as a cost-effective and good performing adsorbent for radioactive waste solutions.

Natural coagulants from chestnut shells: A sustainable approach for textile wastewater treatment.

The textile industry contributes to 2-10% of global greenhouse gas emissions, water extraction, and biodiversity loss, consuming 93 billion cubic meters of water annually with low reuse rates. Coagulation/flocculation is commonly used for industrial wastewater treatment, typically using conventional coagulants. Recently, interest in natural alternatives, particularly tannin-based coagulants, has grown. Given Portugal's role as a major chestnut producer and textile exporter, this study developed chestnut shell-based coagulants for textile wastewater treatment. Ethanolamine (ETA) and diethanolamine (DEA) were tested in the Mannich reaction, but only ETA produced a coagulant with a positive zeta potential and higher charge density. Five coagulants (CE_1-CE_5) were synthesized using different ETA/tannin and formaldehyde (FA)/tannin ratios. Lower ETA concentrations (7.5molL-1) produced the coagulant with the highest charge density and zeta potential. Further testing of FA/tannin ratios (3.5, 6, and 7.5) showed that lower FA levels reduced color removal efficiency and increased toxicity. Comparing synthetic and real textile effluent performance, natural coagulants showed superior color removal, while FeCl3 was more effective for organic matter and nitrogen removal. All coagulants removed phosphorus, with CE_2 achieving nearly 70% removal. Toxicity tests revealed that only CE_5 inhibited V. fischeri bacteria by over 70%. Formaldehyde leaching into treated water was minimal (0.17-0.3mgL-1), below WHO limits (2.6mgL-1), but concentrations in sludge were higher, especially in CE_3 and Tanfloc. These findings highlight chestnut shells as a promising source for producing natural, effective coagulants.

Advanced Oxidation Process UV/H₂O₂ Applied to the Treatment of Synthetic Industrial Effluent Containing Different Organic Dyes

Objective: The objective of this study is to investigate dye removal through the application of advanced oxidation using hydrogen peroxide and ultraviolet light. Theoretical Framework: Dyes are molecules that, even at low concentrations, can alter the color of a product. In most cases, they are resistant to degradation by biological processes and generally exhibit low removal efficiencies. For these cases, in which biological treatment is ineffective, Advanced Oxidation Processes (AOPs) emerge as an effective alternative for the treatment of effluents containing toxic and biologically recalcitrant pollutants. AOPs involve the generation of highly reactive and non-selective oxidizing species, particularly hydroxyl radicals (•OH), to degrade persistent pollutants in industrial effluents, surface water, and groundwater. The UV/H₂O₂ process is an AOP that offers several advantages over other processes, mainly because it does not generate solid residues post-reaction; it is entirely consumed and does not produce byproducts. Method: The methodology adopted in this research involved the use of a bench-scale photochemical reactor in which the dyes Cromax Yellow AT, Cromax Blue AT, and Brown were applied. Dye removal was achieved through advanced oxidation using hydrogen peroxide (H₂O₂) and ultraviolet light (UV). Data collection was conducted through spectrophotometry.Results and Discussion: The results obtained revealed [synthesize the main results of the research]. In the discussion section, these results are contextualized in light of the theoretical framework, highlighting the implications and relationships identified. Possible discrepancies and limitations of the study are also considered in this section. Results and Discussion: Color removal efficiencies of 85% and 95% were obtained at 30 and 60 minutes, respectively, for Cromax Yellow AT, Cromax Blue AT, and Brown. The dye removal kinetics were determined to follow a pseudo-first-order model, with a pseudo-first-order rate constant of 8.75 × 10⁻² min⁻¹ and a half-life of 7.92 minutes. Research Implications: The results demonstrate that advanced oxidation using H₂O₂ and UV is effective for removing the studied dyes, which is relevant for environmental protection and pollutant mitigation. Originality/Value: This study contributes to the literature by evaluating the removal efficiency through the application of H₂O₂ and UV, both of which are readily available and easy to apply. The relevance and value of this research are underscored by its practical implications for effluent treatment.

Clarification of Effluents Industry Using Nb2O5

The effluent treatment from the packaging industry, particularly color removal, is strongly influenced by process interferences. High concentrations of dyes often make water reuse unfeasible. In this context, the present work aims to study the clarification of the dye used in the packaging industry by the photocatalytic process. Niobium was used as a catalyst, which was characterized by different techniques. Before verifying the catalytic activity in the industrial effluent, tests were performed with synthetic dye solutions. As a characterization result, it was possible to identify typical characteristics of the semiconductor. The results with the synthetic effluent indicated that the photocatalytic reaction was adequate for the decolorization of the solution. The optimized conditions indicated pH conditions without adjustments (4.2) and a catalyst concentration of 1.0 g L−1, obtaining a decolorization of 98%. Tests with industrial effluent revealed that the optimum conditions were also obtained with an unadjusted pH (6.2) and catalyst concentration of 6.0 g L−1, obtaining, however, 42% discoloration. This result highlights the influence of the organic load and other interfering factors such as additives. However, the process is promising in the clarification of the effluent, which possibly, with a 42% reduction in color, can be reused in the process generating water sustainability. A curve adjustment was proposed to determine the best conditions obtained for both synthetic and industrial effluents.

Enhancing polyethersulfone microfiltration membranes with chitosan and sodium alginate: a synergetic approach for improved dye removal and flux recovery

This study focused on the surface modification of polyethersulfone (PES) microfiltration membranes using chitosan (CHS) and sodium alginate (ALG), specifically for the removal of textile dyes. The primary objective was to enhance membrane performance in terms of permeability and resistance to fouling, which is crucial for long-term use. A layer-by-layer (LbL) deposition technique was employed to coat the membrane surface with alternating layers of CHS and ALG, creating a bilayer configuration. Various characterization techniques, such as contact angle measurements, Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM), confirmed successful membrane modification. These analyses demonstrated a slight reduction in hydrophilicity and decreased fouling. The performance of the modified membranes was evaluated using aqueous solutions of the reactive red 141 dye (RR141). Results showed that the modified membranes, especially MF CHS1ALG1 and MF CHS1ALG1.5, achieved remarkable dye removal efficiencies exceeding 98%. The MF CHS1ALG1.5 membrane was the top performer, attaining 100% dye rejection and approximately 70% flux recovery across four filtration cycles while maintaining dye rejection rates above 84%. Furthermore, tests using synthetic textile effluent with RR141 demonstrated high dye rejection (98.3%), highlighting the potential of this modification for treating textile effluent, even in the presence of salts.

Performance evaluation of cationic cellulose for anionic dyes adsorption from real wastewater and docking studies

In this study, cationic cellulose fiber adsorbent was prepared through a two-step reaction from commercial cellulose, using an oxidizing agent (sodium periodate) and Girard’s reagent as a cationizing agent. The performance of cationic cellulose for adsorption and separation dye was examined by anionic organic dyes. The prepared adsorbent was able to remove the dyes with the maximum adsorption capacity for Eriochrome Cyanine R, methyl orange, and Zincon being 65.33, 63.33, and 65.32 mg/g, respectively. To explore the adsorption mechanism of the sorbent, the influence of pH, initial dye concentration, contact time, temperature, and adsorbent dose on the activity of adsorption towards anionic dyes were studied, as was the equilibrium dose of cationic cellulose (0.075 g) for removal of 100 mg/L from the studied dyes. The equilibrium data adsorption of cationic cellulose was discovered to be suitable well to the Langmuir isotherm model with correlation coefficient (R2 > 0.982) and pseudo-second-order model. The process of dyes adsorption on cellulose functionalized was spontaneous exothermic (∆G and ∆S < 0), monolayer chemisorption. Utilizing the molecular operating environment software, molecular docking simulations were performed for the cellulose functionalized compound. The results from the docking simulation demonstrated that the modified cellulose compound exhibited increased potency and displayed a higher binding affinity towards the Avr2 effector protein obtained from the fungal plant pathogen Fusarium oxysporum (code 5OD4). The modified cellulose was successfully utilized for the anionic dyes removal from real wastewater samples and synthetic effluents, with a recovery % of more than 87%. The distinctive complementary features of regenerated cellulose will facilitate its removal of a variety of organic dyes from wastewater of industries.

Chlorination of Antivirals in Wastewater: Effects of Microplastics and Ecotoxicity on Aquatic and Terrestrial Species

The presence of pharmaceuticals in wastewater raises concerns about the toxicological risks associated with its discharge and reuse. During the COVID-19 pandemic, widespread use of antivirals (ATVs), along with plastic gloves and masks, further contributed to pharmaceuticals in wastewater. Chlorination, commonly used for wastewater disinfection, may alter the toxicity of antivirals in the presence of microplastics (MPs) and complex organics in secondarily treated wastewater. To investigate this, synthetic secondary effluent containing Favipiravir (FAV) and Oseltamivir (OSE) was exposed to various chlorination conditions, both with and without MPs. The changes in the concentrations of FAV and OSE were measured using LC-MS/MS with isotopically labeled standards. Chlorination was more effective in removing Favipiravir (42 ± 4%) than Oseltamivir (26 ± 3%). The ecotoxicological effects were assessed on two species—Aliivibrio fischeri (a bacterium) and Enchytraeus crypticus (a soil invertebrate)—to evaluate potential impacts on aquatic and soil environments, though discharge of or irrigation with treated wastewater, respectively. Results indicated that chlorination of wastewater itself increased toxicity more significantly than the chlorination of antivirals to either species, suggesting that chlorination may not be as beneficial despite its cost-effectiveness. The effects of MPs in chlorinated wastewater on toxicity highlighted the importance of sample matrices in environmental toxicity studies.

Degradation and ecotoxicity of favipiravir and oseltamivir in the presence of microplastics during ozonation and catalytic ozonation of synthetic municipal wastewater effluents

Abstract BackgroundFavipiravir (FAV) and oseltamivir (OSE) are antiviral agents developed against influenza and they were repurposed against SARS‐CoV‐2 during the COVID‐19 pandemic. This study evaluated the potential of ozonation and catalytic ozonation as tertiary treatment approaches for removing FAV and OSE from municipal wastewaters, both in the presence and absence of microplastics (MPs), while comparing the ecotoxicity of untreated and treated secondary effluents to predict the ecotoxicological effects of these technologies during municipal wastewater treatment.ResultsAt an initial antiviral concentration of 50 μg L−1, ozonation at pH 7 with a specific ozone dose of 0.6 mg O3 (mg DOC)−1 yielded FAV and OSE removals of 84 and 64%, respectively, while the presence of catalyst or MPs decreased the degradation rate by 30–40%. Raising the pH to 10 had minimal impact on FAV abatement, but improved OSE reduction by 21%. Acute toxicity tests using Vibrio fischeri demonstrated that simultaneous ozonation of the analytes led to the accumulation of transformation products (TPs) of FAV and OSE, with their combined effect almost equal to that of the original compounds. Reproduction toxicity tests indicated that TPs of antiviral drugs generated during ozonation were less toxic to Enchytraeus crypticus than the parent chemicals.ConclusionOzonation proved to be a viable option for upgrading existing wastewater treatment facilities, serving as a complementary treatment to minimize the release of antivirals from municipal secondary effluents and reduce their inhibitory effect on earthworm reproduction, thereby enhancing the reuse potential of treated wastewater for irrigation. © 2025 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley &amp; Sons Ltd on behalf of Society of Chemical Industry (SCI).

Synthesis and characterization of polyaniline, sucrose octaacetate and chitosan blend for removal of remazol black by adsorption: Equilibrium, kinetics, and regeneration.

Synthesis and characterization of polyaniline, sucrose octaacetate and chitosan blend for removal of remazol black by adsorption: Equilibrium, kinetics, and regeneration.

Intensified Biological Oxidation of Ciprofloxacin Using Acoustic Cavitation‐Based Pretreatment

ABSTRACTThe present work investigates the intensification of biological oxidation of ciprofloxacin‐based synthetic effluent using acoustic cavitation‐based pretreatment techniques. Cow‐dung based sludge acclimatized with the effluent was used for the biological oxidation experiments at a 1:3 sludge to effluent loading for a treatment time of 48 h. Conventional biological oxidation resulted in 48.79% CIP degradation, which was demonstrated to be enhanced through acoustic cavitation‐based pretreatment. The optimized conditions for cavitation were 125 W power and a 70% duty cycle, and the optimum oxidant loadings for the combination studies were 150 mg/L H2O2, 150 mg/L of potassium persulfate (KPS), and 200 mg/h of O3. The enhanced CIP degradation after application of pretreatment was 63.27%, 79.23%, 68.27%, and 82.27% for AC, AC + H2O2, AC + KPS, and AC + O3 based pretreated effluents, respectively. Toxicity analysis against test organisms Pseudomonas aeruginosa (P. aeruginosa) and Saccharomyces cerevisiae using the agar well diffusion method confirmed that pretreatment reduced the toxicity leading to enhanced biodegradation. Overall, the current work elucidated the efficiency of acoustic cavitation combined with KPS for the effective biological oxidation of ciprofloxacin.

Detoxification of dairy industry effluent from toxic metal ions: Preparation and characterization of a magnetized adsorbent derived from agricultural residues

This study investigated the potential of a mixture of agricultural wastes for the preparation of an adsorbent and evaluated its efficiency in removing Co(II) and Cu(II) ions. Brunauer-Emmett-Teller analysis revealed a surface area of 89.57 m2/g, a total pore volume of 4.92 cm³/g, and an average pore diameter of 43.26 nm. Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed a layered structure, uniform pore distribution, and successful adsorption of cobalt and copper ions. Vibrating sample magnetometry analysis demonstrated superparamagnetic behavior, with a saturation magnetization of 52.8 emu/g. Fourier-transform infrared spectroscopy identified oxygen-containing functional groups formed during activation, which significantly enhanced the adsorbent’s adsorption capacity. Equilibrium data for pollutant adsorption were well-described by the Freundlich isotherm, with maximum adsorption capacities of 91.7 mg/g for Co(II) and 89.9 mg/g for Cu(II). At 50 °C, the correlation coefficients (R2) were determined to be 0.969 for Co(II) and 0.960 for Cu(II). Under optimal conditions, 75 mg of adsorbent at 50 °C, pH 6.5, and 30 min, the adsorbent achieved 92–93% removal of pollutants from real dairy effluent and 95–96% from synthetic effluent. The process highlights its potential as a sustainable solution for dairy effluent treatment and agricultural waste management, with scalability for industrial applications.

Optimization of Biochar Synthesis from Cosmetic Industry Sludge for Enhanced Removal of Enrofloxacin

Sewage sludge serves as a promising raw material for producing activated biochar (BC), offering both environmental and economic benefits. This work aimed to optimize the synthesis of biochar (BC) from cosmetic industry sludge using response surface methodology (RSM) with central composite rotational design (CCRD) and to assess its effectiveness in removing the antibiotic enrofloxacin (ENR) from synthetic effluents. The input variables considered were (i) residence time in the reactor and (ii) impregnation ratio (NaOH/biomass). The response for optimization was the iodine number. The sludge underwent pyrolysis at 550 °C under a nitrogen atmosphere. The optimized biochar (OBC) had a macroporous structure with a specific surface area of 46.1 m2 g–1 and a calorific value of 4146 kcal kg–1. The bio-oil contained nitrogenous compounds and alcohols. The effectiveness of the OBC in adsorbing ENR in aqueous systems was assessed. Kinetic assays showed an equilibrium time of 90 min, with the pseudo-second-order model best fitting the experimental data. The Langmuir isotherm model best described the adsorption (qmax = 15.83 mg g–1). The material is competitive with commercial adsorbents. This work underscores the potential of industrial sludges as a sustainable source for BC, contributing to pollution reduction and promoting circular economy practices.

Foam investigation and optimization by Response Surface Methodology of electrocoagulation process for textile wastewater decolorization in single-channel reactor

Foam investigation and optimization by Response Surface Methodology of electrocoagulation process for textile wastewater decolorization in single-channel reactor

Evaluation of the efficacy of papaya seed-based natural adsorbent for synthetic textile wastewater treatment

This study explored the application of papaya seed-based activated carbon for removing methylene blue dye from synthetic textile effluent. Batch experiments are used in the study to investigate the adsorption potential of activated carbon. The results demonstrate that papaya seeds derived from activated carbon have the greatest potential for methylene blue adsorption, with an average removal effectiveness of 89.4%. The effects of several parameters such as pH, contact time, adsorbent dose, adsorbent-adsorbate temperature, and starting dye amount or concentration were examined to optimize the adsorption conditions. Maximum dye removal was achieved after 60 minutes of contact time at pH 6.5. The carbon dosage and pH of the solution were discovered to have the greatest influence on the adsorption process. Based on the experimental data, the Langmuir and Freundlich models were identified as the most appropriate fits for the adsorption investigation. In conclusion, activated carbon derived from papaya seeds is a viable and natural bio-adsorbent for removing methylene blue from synthetic textile wastewater.

Bioremediation of synthetic dairy effluent using microalgae for biomass production and the removal of organic pollution load

Dairy wastewater is distinguished by higher BOD and COD levels, as well as substantial amounts of dissolved or suspended solids such as fats, oils, and grease, nutrients such as ammonia or minerals and phosphates, and so demonstrates the significance of treatment prior to discharge. Bioremediation treats effluent by using the naturally occurring microorganisms and other aspects of the natural habitat. Bioremediation may be less expensive than other technologies for hazardous waste cleanup. The present study evaluates the ability of the microalgae Chlorella vulgaris to remove nutrients present in synthetic dairy effluents. Chlorella vulgaris was grown in culture medium with various concentrations of 2g/l, 4g/l and 6g/l respectively for 15 days. At the beginning and end of the investigation, the following variables were determined: ammonia, chloride, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), and pH. The amounts of nitrogen decline in dairy effluent have a significant impact on biomass production. The results showed that the amount of chemical compounds in the effluent had decreased namely, BOD 967mg/l, COD 2765 mg/l, chloride 246 mg/l, Ammonia 6.34 mg/l, Dissolved Oxygen 1.02 mg /l. The results demonstrated that the Chlorella vulgaris for the reduction of pollutants is found potential.

Treatment of Paracetamol and Propranolol Via Anodic Oxidation, Electrolyte Study and Kinetic Analysis

Objective: To evaluate the application of anodic oxidation (AO) for the degradation of paracetamol and propranolol, in aqueous solution and synthetic effluent. Theoretical Framework: Pharmaceuticals are persistent contaminants, requiring more complex technologies for their complete degradation, such as advanced electrochemical oxidative processes. Method: The following electrodes were tested: graphite and copper; and electrolytes: sodium chloride, potassium chloride, odium sulfate and ferrous sulfate heptahydrate and the following variables were evaluated: distance between the electrodes, depth in the solution and voltage. In addition to the degradation kinetics and toxicity tests with lettuce (Lactuca Sativa), carrot (Daucus carota) and tomato (Solanum lycopersicum) seeds. Results and Discussion: The results obtained for the aqueous solution of the drugs were satisfactory in graphite-copper systems with NaCl and KCl, with complete degradation for paracetamol after 75 min. While for propranolol, degradations of 81.28% (NaCl/214 nm) and 72.97% (KCl/214 nm) and 85.92% (NaCl/288 nm) and 81.95% (KCl/288 nm) were identified after 150 min. In the synthetic effluent, a small reduction in degradation was observed, being 84.53% for paracetamol and 62.95% (214 nm)/52.78% (288 nm) for propranolol. Toxic effect was observed for all evaluated seeds. Research Implications: This research shows that even the simplest EAOPs, such as AO, are efficient and applicable in degrading pharmaceutical contaminants efficiently. Originality/Value: This study reiterates the efficiency of AO in degrading two different pharmaceutical contaminants, and the maintenance of this efficiency, even when increasing the complexity of the matrix studied.

Comparative study of the removal of urea by electrocoagulation and electrocoagulation combined with chemical coagulation in aqueous effluents

Urea is a major issue in human wastewater because it may be easily broken down by the urease enzyme produced by bacteria, leading to ammonia production. Due to its ability to increase soil pH and eutrophicate streams, ammonia-containing effluent emissions pose environmental and health risks. This study aimed to evaluate the effectiveness of various treatment approaches in reducing urea concentrations by comparing the removal rates of conducting electrocoagulation (EC), EC followed by chemical coagulation (EC-CC), and CC followed by electrocoagulation (EC-CC). Numerous electrocoagulation parameters have been investigated, including current density, electrode gap distance, electrolyte type, concentration, and electrolysis duration. The electrode morphology was examined using a scanning electron microscope, while the produced sludge was analyzed using Fourier transform infrared spectroscopy. Three kinds of aluminum coagulants—potash alum, aluminum sulfate, and aluminum chloride—were used in the chemical coagulation, while the electrocoagulation was optimized at 30 A/m2. The results of this investigation suggest that the application of EC-CC, regardless of the type of coagulant used in both synthetic and real effluent, could marginally improve the efficacy of urea removal. Conversely, CC-EC exhibits an adverse effect on the efficiency of urea removal in both synthetic and real wastewater. The application of CC-EC demonstrated a significant improvement in the effectiveness of COD removal from actual wastewater, according to experimental results. The study emphasized the effectiveness and economic advantages of electrocoagulation over EC-CC and CC-EC techniques, used to remove urea from both real and synthetic wastewater.