Pollutant Removal Efficiency Research Articles

Synthesis of Copper-Doped Metal Nanoferrites for Efficient Removal of Pharmaceutical Wastewater Pollutants in Membrane Bioreactor System

Pharmaceuticals present in the aquatic environment can poison aquatic species and humans through drinking water and cause harmful bacteria to become resistant. The role of transition metal doped metal nanoferrites for the enhanced efficiency of degradation process is widely achieved. In this work, copper doped magnesium ferrite (Cu-MgFe2O4) and copper doped zinc ferrite (Cu-ZnFe2O4) nanoparticles were synthesized using a sol-gel method. X-ray diffraction (XRD) analysis confirmed the formation of the spinel structure for both samples, with crystal sizes of 16.72 nm and 59.05 nm, respectively. The magnetic properties of the samples were studied using a vibrating sample magnetometer (VSM), which revealed that the addition of Cu2+ ions has a significant impact on the magnetic properties of the nanoparticles. The saturation magnetisation (Ms), retentivity (Mr) and coercivity value (Hc) for the Cu-MgFe2O4 sample were found to be 0.18453 emu, 39.584 × 10-3 emu and 139.61 Oe, respectively, while for the Cu-ZnFe2O4 sample, the values were 0.21271 emu, 71.022 × 10-3 emu and 285.91 Oe, respectively. The impact of copper doped nanoferrites on pollutant removal from pharmaceutical wastewater using the membrane Bioreactor (MBR) system has also been accomplished. The results demonstrated the effectiveness of ferrites in reducing concentrations of heavy metals, including lead and cadmium, within acceptable ranges for inland surface water and public sewers. Furthermore, the MBR system with ferrites exhibited efficient removal of fluoride, sulphide and radioactivity, ensuring compliance with the specified standards. Although the study exhibited the potential of ferrites in pollutants removal, further optimization is necessary to achieve complete compliance with water quality standards.

Transforming Wastewater into Biofuel: Nutrient Removal and Biomass Generation with Chlorella vulgaris

This study investigates the potential of Chlorella vulgaris for nutrient removal and biomass production in synthetic wastewater. The experiments were conducted in 2 L photobioreactors under controlled aeration, agitation, and lighting conditions for 19 days. Despite a moderate growth rate (0.137 d⁻¹), C. vulgaris achieved efficient pollutant removal, with 97% of nitrate, 90% of nitrite, and 90.6% of COD eliminated. Additionally, the biomass was processed to extract fatty acids, yielding a 20% extraction rate, indicating its potential as a biofuel feedstock. These results demonstrate C. vulgaris’s dual function in wastewater remediation and biofuel production, presenting a sustainable and economically viable approach to addressing environmental challenges.

Structural design of hierarchical porous biomass carbon with a built-in electric field for efficient peroxymonosulfate activation

Biomass-derived carbon materials have excellent adsorption capacity and cost-effectiveness, and the electron interactions between multiphase composite materials improve the efficiency of water pollutant removal by advanced oxidation processes (AOPs). Herein, a multistage biochar catalyst in which metallic cobalt-embedded carbon tubes are prepared uniformly on the surface of kapok tubes is designed and fabricated. The closely connected structure grown in situ accelerates electron migration and forms a directional transfer electric field. The N-doped carbon nanotube encapsulated Co nanoparticles growth on the kapok biochar/PMS (Co-N-KBC/PMS) system removes tetracycline hydrochloride (TCH) at a rate 11.8 times higher than that of KBC/PMS. Free radicals (SO4•−, •OH, and •O2–) and non-free radicals (1O2) are generated in conjunction with electron transfer during PMS activation. The cobalt sites and C=O groups are possible active sites. Density-functional theory (DFT) calculations verify the built-in electric field from N-KBC to the Co surface, which accelerates electron transfer and improves TCH removal. The results reveal an effective strategy to activate PMS and address environmental remediation by utilizing carbon materials derived from biomass.

Solar photocatalytic degradation of model naphthenic acids mixtures by Bi2WO6 and Bi2WO6/NiO/Ag: Exploring the influence of inorganic fraction of oil sands process water

This study investigates the comparative photocatalytic degradation of six model naphthenic acids, key organic constituents responsible for the toxicity of oil sands process water, using the semiconductor photocatalysts Bi2WO6 and Bi2WO6/NiO/Ag in both buffered solution and the inorganic fraction of OSPW. The heterojunction catalyst (Bi2WO6/NiO/Ag) exhibited the highest removal efficiencies for these organic pollutants with k values 0.048, 0.036, 0.019, 0.283, 0.026, and 0.075 min−1 for 1-adamantanecarboxylic acid, cyclohexanecarboxylic acid, tetrahydropyran-4-carboxylic acid, tetrahydro-2H-thiopyran-4-carboxylic acid, isonipecotic acid, and 4,5-dihydronaphtho[1,2-b]thiophene-2-carboxylic acid, respectively. Experimental analysis suggested that chloride and bicarbonate inhibited the photocatalytic degradation of the target naphthenic acids, while nitrate could accelerate the production of aminyl radicals, enhancing the degradation of isonipecotic acid. Notably, four additional nitrated and hydroxylated by-products were identified during 1-adamantanecarboxylic acid degradation in the presence of nitrate. The addition of the catalyst not only accelerated the degradation rate of 1-adamantanecarboxylic acid but also helped mitigate the formation of potentially toxic by-products. Additionally, the transformation products of 4,5-dihydronaphtho[1,2-b] thiophene-2-carboxylic acid were identified. Degradation pathways were further elucidated with the assistance of density functional theory calculations, identifying the β-carbon as the initial reactive site, with the sulfur atom also playing a significant role in reactivity. These findings contribute to the understanding of the water matrix-induced transformation process of model naphthenic acids during photocatalytic treatment, enhancing the environmental applicability of photocatalytic treatments.

Porous polylactide membranes with high piezo-catalytic efficiency for organic wastewater treatment

Piezo-catalysis has been emerged as a green and promising wastewater treatment technology for efficient removal of persistent organic pollutants (POPs), such as 4-nitrophenol (4-NP). However, it remains challenging to achieve advanced materials with combined advantages of high piezo-catalytic efficiency, good hydrophilicity, and environmental friendliness. In this work, highly crystalline porous polylactide (PLA) membranes possessing such exceptional advantages have been successfully prepared from biodegradable poly(L-lactide)/poly(D-lactide)/polyethylene glycol/polyoxyethylene-polyoxypropylene block copolymer (PLLA/PDLA/PEG/PEO-PPO-PEO) blends by melt processing and subsequent water etching. During the melt-processing, the two PLA enantiomers co-crystallize into stereocomplex (SC) crystals and simultaneously the PEG used as a porogen is expelled from the crystalline regions. The results show that the prepared PLA membranes have not only abundant micro-porous structures but also good hydrophilicity due to the preferential localization of PEO-PPO-PEO copolymer on the pore walls, thus giving rise to an extremely high water flux of 2400 L/m2h. More interestingly, the PLA membranes exhibit remarkable piezoelectric activity and the piezo-catalytic degradation efficiency of 4-NP can reach as high as 96 % under the triggering of water flow involved in vacuum filtration. In addition, the membranes show excellent reusability and the high catalytic efficiency can be well-maintained after five repeated uses. These findings suggest broad application prospects of our porous SC-PLA membranes in organic wastewater treatment.

A Miniaturized, Fuel-Free, Self-Propelled, Bio-Inspired Soft Actuator for Copper Ion Removal.

We present a novel miniaturized, gear-shaped, fuel-free actuator capable of autonomously propelling itself in an aquatic environment to absorb heavy metals, such as copper ions. While hydrogel-based absorbents are promising solutions for cationic pollutant remediation, their stationary nature limits their effectiveness in areas where contaminants are unevenly distributed. To address this, we developed a bio-inspired soft actuator that mimics natural propulsion mechanisms. The Marangoni effect, driven by its inherent chemical properties, demonstrated a self-propelled motion without requiring external fuel. The proof-of-concept actuator generated a plane motion lasting up to 2 h and swept over an area approximately 400 times bigger than its size. By harnessing the chemical and optical properties of the hydrogel, we efficiently removed and quantitatively analyzed copper ions through a colorimetric method. This innovative integration of self-propelled movement and efficient copper ion absorption underscores its potential for advancing miniaturized devices in environmental remediation, paving the way for more active and efficient pollutant removal systems in challenging aquatic environments.

Poly(methyl methacrylate) functionalized graphene oxide/CuO as nanocomposite for efficient removal of dye pollutants

In this research, the use of a three-component nanocomposite of graphene oxide-methyl methacrylate and copper(II) oxide (PMMA-GO-CuO) was investigated. The aim of synthesizing this nanocomposite is to removal dye pollutants, specifically methylene blue (MB) and methyl orange (MO), which are commonly used in dyeing industries, through adsorption. The study focuses on creating GO-CuO and PMMA-GO-CuO nanocomposites as effective adsorbents. A simple and quick method led to the development of the PMMA-GO-CuO nanocomposite, which shows enhanced physical and chemical properties. Key materials include graphene oxide, methyl methacrylate, and copper(II) oxide nanoparticles. Characterization techniques such as FT-IR, XRD, SEM, and TGA were used to analyze the nanocomposite. Results indicate that dye adsorption is more effective at lower pH levels, suggesting that the PMMA-GO-CuO nanocomposite can efficiently remove dyes from industrial wastewater. The experimental data showed that the Langmuir isotherm model accurately represented the equilibrium adsorption, with maximum capacities of 285.71 mg g−1 for methylene blue and 256.41 mg g−1 for methyl orange, indicating a single layer of adsorption. The kinetics followed a pseudo-second order model, suggesting that the adsorption process involves chemical bonding. Additionally, thermodynamic parameters (ΔG°, ΔH°, and ΔS°) indicated that the adsorption is spontaneous. The adsorption mechanism involves hydrogen bonding, π-π interactions, and electrostatic interactions. This study investigates how factors like pH, temperature, contact time, and dye concentration affect the adsorption of methyl orange and methylene blue dyes. A PMMA-GO-CuO nanocomposite was used, achieving 84% removal of MB and 35% removal of MO from industrial wastewater. This study highlights the promising potential of PMMA-GO-CuO nanocomposite as an effective material for the removal of dye pollutants from industrial wastewater. The results showed that the graphene oxide in the composite is effective for removing cationic dyes due to its negative charge. Further research will focus on the optimization of the synthesis process with the aim of achieving competitive performance of this nanocomposite on a large scale. These findings not only advance the field of nanocomposite materials but also provide a practical solution to an important environmental issue, demonstrating the innovation of the present study in the literature.

Assessing the electrode configuration in a sandbox system for the removal of sulfanilamide: A pilot study

Electrochemical oxidation has emerged as an effective and straightforward technology for groundwater remediation. While recent studies have investigated parameters such as current, electrolyte composition, and electrode materials, most have been conducted using small-scale batch or flow reactors, limiting their applicability to real-world conditions. In this study, a pilot-scale sandbox reactor was employed to simulate realistic groundwater conditions and assess the removal of sulfanilamide, a model organic contaminant. Various electrode configurations were systematically evaluated to identify the key operational parameters influencing pollutant removal efficiency, providing insights for practical applications in groundwater treatment. This study proposes three configurations, including a single well with the anode and cathode, a double well with the separated anode and cathode, and an e-barrier with electrodes separately mounted inside a permeable barrier. Single well had the lowest removal efficiency (60%) because cathodic reaction inhibited the anodic oxidation. A double well with a separate anode and cathode can achieve 80% removal efficiency. However, effluent pH can reach up to 13.2, which can adversely impact groundwater. Meanwhile, the e-barrier not only achieved complete removal, but also maintained a neutral pH of 7.0 over 30 days. The e-barriers proved to be the most effective configuration based on their removal efficiency (100%) while yielding an effluent with neutral pH. The energy consumption of the e-barrier was most effective at 1.54 kWh/m3, while the other configurations were 5.40 and 22.18 kWh/m3. E-barriers are deemed a very reasonable configuration, both in terms of removal efficiency and practical application in groundwater.

Promoting Electricity Production and Cr (VI) Removal Using a Light–Rutile–Biochar Cathode for Microbial Fuel Cells

Microbial fuel cell (MFC) technology holds significant promise for the production of clean energy and treatment of pollutants. Nevertheless, challenges such as low power generation efficiency and the high cost of electrode materials have impeded its widespread adoption. The porous microstructure of biochar and the exceptional photocatalytic properties of rutile endow it with promising catalytic potential. In this investigation, we synthesized a novel Rutile–Biochar (Rut-Bio) composite material using biochar as a carrier and natural rutile, and explored its effectiveness as a cathode catalyst to enhance the power generation efficiency of MFCs, as well as its application in remediating heavy metal pollution. Furthermore, the impact of visible light conditions on its performance enhancement was explored. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analysis validated the successful fabrication of rutile composites loaded with biochar. The maximum current density and power density achieved by the MFCs were 153.9 mA/m2 and 10.44 mW/m2, respectively, representing a substantial increase of 113.5% and 225% compared to the control group. In addition, biochar-supported rutile MFCs showed excellent degradation performance of heavy metal pollutants under light conditions. Within 7 h, the Cr6+ degradation rate reached 95%. In contrast to the blank control group, the removal efficiency of pollutants exhibited increases of 630.8%. The cyclic degradation experiments also showcased the remarkable stability of the system over multiple cycles. This study successfully integrated natural rutile and biochar to fabricate highly efficient cathode photocatalyst composites, which not only enhanced the power generation performance of MFCs but also presented an environmentally sustainable and economically viable method for addressing heavy metal pollution.

A new catalyst derived from the sulfur-doped metal-organic framework for Fenton-like reaction

Fenton-like reaction exhibits considerable advantages in the remediation of pollutants. To fabricate an efficient catalyst becomes an issue concerning the performance enhancement in Fenton-like reaction. Herein, S-Fe-MOF-400 which was derived from a sulfur-doped metal-organic framework (Fe-MOF), was newly prepared and exhibited high ability for H2O2 activation during Fenton-like reaction. The results showed that the sulfurization effectively reduced the charge transfer resistance (Rct) of S-Fe-MOF-400, and facilitated the charge transfer, consequently enhancing the catalytic performance of S-Fe-MOF-400 in the Fenton-like reaction. XRD analysis revealed that FeS2 was the predominant reactive component in S-Fe-MOF-400 with a regular cubic structure and pronounced crystallinity. Additionally, the presence of low-valent sulfur ensured the availability of Fe (II), thereby facilitating the occurrence of the Fenton reaction. Under optimal conditions, the removal efficiency of pollutants reached 86.7 % within 60 min, resulting in total organic carbon (TOC) removal efficiency at 40.6 %. Quenching experiments and electron paramagnetic resonance (EPR) detections revealed that •OH, 1O2, and O2•− synergistically participated in the Fenton-like reaction, with •OH being the primary active species. The activation process of H2O2 induced by S-Fe-MOF-400 mainly yielded hydroxyl radicals and superoxide radicals. The 1O2 was generated through two following pathways: (i) the transformation of superoxide and hydroxyl radicals, and (ii) the conversion of natural oxygen molecules (O2). This current study illustrated the significant potential for the application of sulfur-modified Fe-MOF in the Fenton-like reaction for pollutant removal.

Regeneration of Ti Coagulants from Water Treatment Sludge Using acid Leaching: Efficiency in Turbidity and Pollutant Removal

Regeneration of Ti Coagulants from Water Treatment Sludge Using acid Leaching: Efficiency in Turbidity and Pollutant Removal

Catalytic Ozonation Treatment of Coal Chemical Reverse Osmosis Concentrate: Water Quality Analysis, Parameter Optimization, and Catalyst Deactivation Investigation.

Catalytic ozone oxidation, which is characterized by strong oxidizing properties and environmental friendliness, has been widely used in organic wastewater treatments. However, problems such as a low organic pollutant removal efficiency and unstable operation during the catalytic ozone treatment process for wastewater remain. To address these disadvantages, in this study, the treatment efficacy of catalytic ozone oxidation on a coal chemical reverse osmosis concentrate was investigated. The basic water quality indicators of the chemical reverse osmosis concentrate were analyzed. The effects of initial pollutant concentration, pH, ozone concentration, and catalyst concentration on the COD removal rate from the coal chemical reverse osmosis concentrate were explored. Water quality indicators of the chemical reverse osmosis concentrate before and after the catalytic ozone treatment were studied using spectroscopic analysis methods. The RO concentrate demonstrated large water quality fluctuations, and the catalytic ozonation process removed most of the pollutants from the treated wastewater. A possible deactivation mechanism of the ozone catalyst was also proposed. This study provides a theoretical reference and technical support for the long-term, efficient, and stable removal of organic pollutants from coal chemical reverse osmosis concentrate using a catalytic ozone oxidation process in practical engineering applications.

Larger shrubs can maintain high infiltration and evapotranspiration rates in experimental biofiltration systems impacted by high sediment loads

Biofiltration systems can fail over time due to clogging by fine sediments in stormwater. Infiltration can be maintained by plant roots, but species selection for biofiltration to date has largely been driven by pollutant removal efficiency and tolerance of conditions. As a result, plant species diversity in biofilters is typically low and dominated by sedges and rushes. Increased use of woody species could in theory improve plant diversity, aesthetic appeal, infiltration under high sediment loads and volumetric runoff reduction via higher evapotranspiration, without jeopardising nutrient pollutant removal. We tested whether shrubs could maintain infiltration and evapotranspiration in biofiltration profiles treated with a high sediment load, by comparing them with biofilters subjected to tap water without sediment. Following sediment application, biofilter columns planted with shrubs with high total biomass and total root length showed higher infiltration and evapotranspiration than those receiving tap water. These results indicate that shrub species are likely to alleviate clogging and increase stormwater retention in biofiltration systems. However, shrubs with a high root diameter also had low total biomass and total root length and showed 33–51 % lower infiltration rates after sediment application compared with those receiving tap water. As all shrubs had higher root diameters than typical sedges and rushes, we suggest that shrubs need a combination of higher total biomass, total root length and average root diameter to effectively maintain infiltration. While shrubs which maintained infiltration had traits associated with high nutrient removal, nutrient removal efficiency of shrubs needs to be quantified. Although root traits were related to maintenance of infiltration, above-ground stems likely created flow pathways through sediment which requires further investigation. Overall, selecting shrub species with high total biomass has the potential to maintain infiltration and increase evapotranspiration in biofiltration systems impacted by high sediment loads.

Environmental, technological, and economic analysis of supercritical coal-fired power system.

Developing countries primarily rely on fossil-based energy sources to meet their energy demands. The use of fossil fuels has several adverse environmental repercussions that damage the biosphere both directly and indirectly. Among fossil fuels, coal brings about the heaviest environmental externalities, yet its abundance makes its use widespread, particular in countries having significant power generation deficits, such as Pakistan. This study presents an environmental, technological, and economic analysis of a supercritical coal-based power unit located in Pakistan and used for electricity generation. For environmental assessment, the CML-1A baseline method in OpenLCA software was used, and eight midpoint impact indicators were selected. The functional unit chosen was 1 MWh of generated electricity. The results indicated that the category of ozone layer depletion has the least impact, whereas global warming potential has the highest impact score. Except for photochemical oxidation and human toxicity, the plant operational stage dominated most of the selected impact categories. The current paper also reveals that the removal efficiency of CO2 and other pollutants is higher in supercritical compared to subcritical plants. Moreover, the economic feasibility of supercritical plant is compared with chemical looping combustion (CLC)-based supercritical coal-fired power plant, and results shows that CLC-based coal-fired power plant is a more competitive and environmentally friendly option. The utilization of a scientific cleaner energy-management system in real-time, as exemplified in this study, may facilitate the development of a optimalpolicy framework that encouragesfor the adoption of cleaner coal power generation in developing countries, ultimately resulting in improved energy sustainability. Furthermore, this paper also presents some policy implications which could be helpful for policymakers, researchers, and industrialists to improve the sustainability of energy in emerging economies.

Advancing environmental remediation through tailored TiO2 nanomaterials in water and air purification

This study investigates the green synthesis of TiO2 nanoparticles at varying concentrations (0 %, 0.1 %, 2.5 %, 5 %, and 10 %) using Viola betonicifolia plant extract, focusing on their application in environmental purification, specifically in water and air decontamination. X-ray diffraction (XRD) analysis confirmed the anatase crystal structure of TiO2 nanoparticles, with an average crystallite size of approximately 22 nm. Transmission electron microscopy (TEM) revealed a median diameter of around 22 nm, corroborating the findings from XRD. The effectiveness of these TiO2 nanomaterials was evaluated through bench-scale models simulating real-world conditions, targeting a broad range of pollutants, including heavy metals, organic dyes, volatile organic compounds (VOCs), and microbial pathogens. Advanced analytical techniques such as High-performance liquid chromatography (HPLC), Inductively coupled plasma mass spectrometry (ICP-MS), and microbial plate count methods quantified the pollutant removal efficiency, demonstrating the significant potential of the synthesized TiO2 nanoparticles. Dynamic light scattering (DLS) analysis showed a mean hydrodynamic diameter of 22 nm and a polydispersity index (PDI) below 0.1, indicating a uniform size distribution. The FTIR spectrum revealed a broad absorption band at 3400 cm−1, corresponding to O–H stretching vibrations, indicative of hydroxyl groups crucial for the photocatalytic activity of TiO2. The UV–visible spectroscopy indicated a maximum absorption at 642 nm, associated with the п-п* transition. Photocatalytic degradation of methylene blue under UV irradiation achieved a degradation efficiency of 94 % after 120 min, underscoring the superior efficiency of the green synthesis method.

Voltage-confined flow-through anodic oxidation enables efficient pollutant removal and no chlorinated byproducts formation

The formation of chlorinated by-products in the treatment of chloride-laden water/wastewater by advanced oxidation processes (AOPs) has become a severe challenge to their environmentally benign application. Herein, we propose an efficient and safe alternative, i.e., flow-through anodic oxidation (FTAO) system based on the nonradical direct electron transfer (DET) process at low voltage. By controlling the anode potential below the threshold for chlorine evolution at the anode, this system achieved zero formation of inorganic and organic chlorinated byproducts whilst significantly eliminated the biotoxicity of the parent micropollutant. Meanwhile, due to the nonradical direct oxidation mechanism, the voltage-confined FTAO system attained high efficiency and selectivity for the micropollutant removal from a complex matrix containing naturally co-existing anions and organic matter. The feasibility of FTAO applications was further evaluated by removing various pollutants (including antibiotics and phenols) from actual municipal effluent and surface water. More than 96% percentage removal was achieved at extremely low energy consumption (0.003–0.017 kWh m−3). In summary, our results provide insight into the development of novel electrochemical technologies free from secondary pollution towards environmental remediation applications and beyond.

Visible-light-driven Z-scheme ZnTe/WO3 heterojunction for simultaneous elimination of tetracycline and Cu(II)

Z-Scheme heterojunction photocatalysts can effectively suppress the recombination of charge carriers while maintaining high redox capacity. In this study, ZnTe/WO3 (ZW) Z-scheme heterojunction photocatalysts were synthesized using a hydrothermal method, and a series of photocatalytic materials were prepared for the simultaneous removal of tetracycline (TC) and Cu(II) from water. The physicochemical and photoelectrochemical properties of the catalytic materials were characterized through various methods, including SEM, XRD, XPS, and others. The experimental results indicate that the ZW-10 % composite material exhibits the most significant removal efficiency for pollutants. Within 150 min of visible light irradiation, the removal rates for TC and Cu(II) reach 73.8 % and 73.3 %, respectively, representing a substantial improvement compared to individual ZnTe and WO3. Free radical capture experiments and electron spin resonance analysis reveal that ·O2− and ·OH are the key reactive species responsible for TC oxidation, while electrons (e−) dominate the reduction of Cu(II).

3D Porous Gel from the Orthogonal-junction of Nanosheet Photosensitizers with Efficient and Selective Photosensitization

Photocatalysis waste decomposition is a promising candidate for efficient cleaning of volatile organic compounds (VOCs) with enhanced safety because of the self-degradation of toxic compounds by reactive oxygen species (ROS) under light irradiation. However, the complete removal of pollutants remains challenging due to the inert characteristics of their inactivity in the presence of electrophilic ROS. Herein, a new strategy for efficient degradation of inert VOCs such as benzaldehyde has been proposed, basing on the synergism of selective adsorption and chemical activation by the construction of 3D porous gel through an orthogonal-junction of nanosheet-shaped photosensitizers. The key to the success of the combination is the use of hierarchically assembled hydrogen bonded laminates (HBLs) as gelation scaffolds. The backbone could integrate organic photosensitizers (PSs) into robust gel skeleton with enhanced ROS generation, which promotes the photocatalytic degradation. Especially, the backbone is able to directionally recognize glue clusters by hydrogen bonding to result in orthogonal 3D gel, giving remarkable selective adsorption for inert aromatic aldehydes. The synergistic integration of chemical activation and selective entrapment gives rise to unusual rapid photo-degradation for carbonyl compounds, resulting in efficient removal of inert pollutants from the environment without any adverse effect.

Treatment of aircraft maintenance wastewater by coupling low-temperature evaporation with Fe–C micro-electrolysis-configured ozonation

ABSTRACT A novel approach combining low-temperature evaporation with Fe–C micro-electrolytic ozone oxidation has been devised for treating substantial volumes of high-concentration organic cleaning wastewater generated during aircraft maintenance activities. The findings from experiments demonstrate impressive average removal rates for various contaminants, including chemical oxygen demand (93.1%), oil concentration (94.0%), suspended solids (98.9%), turbidity (98.8%), chroma (93.8%), total nitrogen (93.7%), and total phosphorus (99.2%). Within this integrated system, the synergistic effects between ozone oxidation, catalytic fillers, and electrochemical processes significantly enhance pollutant removal efficiency. The chemical oxygen demand reduction rates of the cleaning wastewater derived from engine maintenance, mechanical and electrical maintenance, aircraft accessory maintenance, and mixed wastewater exceed 98%. The optimal reaction times for four types of wastewater are 150, 120, 90, and 120 min, respectively. The time can be adjusted according to the different treatment objects in actual operation projects. Moreover, the average concentration efficiency achieved surpasses 92% while meeting all effluent quality standards set forth by municipal sewage networks, and it has reduced the disposal cost of the enterprise by about 80%. This technology provides enterprises with an effective way to reduce energy consumption and expenses.

Evaluation of the pollutant removal efficiency of swine wastewater through two configurations of hybrid wetlands with tropical ornamental plants

The pig farming industry in Mexico is an important economic activity that is growing significantly, generating large volumes of wastewater that negatively affect water bodies and human health. The lack of adequate treatment systems exacerbates this problem. Hybrid constructed wetlands that combine Vertical Flow Constructed Wetlands (VF-CWs) and Horizontal Flow Constructed Wetlands (HF-CWs) offer an economical and effective treatment using natural processes. The objective was to evaluate the removal of contaminants from pig farm wastewater using two configurations of hybrid systems with ornamental plants. Two configurations were established: System I: VF-CWs + HF-CWs and System II: HF-CWs + VF-CWs. The VF-CWs were planted with Canna hybrids and the HF-CWs with Heliconia latispatha. The results indicated higher removal efficiencies of organic matter, nitrogen, and phosphorus in System I (BOD5: 72.99 %, COD: 71.41 %, TN: 79 %, NH4+: 84.31 %, NO3-: 74.29 %, TP: 59.54 %, FC: 99.88 %) compared to System II (BOD5: 66.80 %, COD: 67.01 %, TN: 77.90 %, NH4+: 82.31 %, NO3-: 70.48 %, TP: 55.81 %, FC: 99.89 %), regarding FC, the same results were obtained in both systems. Both plant species showed vigorous development, although the growth of Heliconia latispatha was more notable. In conclusion, the results suggest that the VF-CWs + HF-CWs configuration in hybrid wetlands could be a suitable option for treating this type of effluent.