Pollutants In Wastewater Research Articles

Unveiling electron transfer and radical transformation pathways in coupled electrocatalysis and persulfate oxidation reactions for complex pollutant removal

The degradation of multiple organic pollutants in wastewater via advanced oxidation processes might involve different radicals, of which the types and concentrations vary upon interacting with different pollutants. In this study, electrochemical activation of peroxymonosulfate (E/PMS) using advanced activated carbon cloth (ACC) as electrode was applied for simultaneous degradation of mixed pollutants, e.g., metronidazole (MNZ) and p-chloroaniline (PCA). 92.5 % of MNZ and 91.4 % of PCA can be degraded at the cathode and anode at a low current density and PMS concentration, respectively. The rate constants for the simultaneous removal of MNZ and PCA in the E/PMS/MNZ(PCA) system were 118 times and 6 times higher than those in the sole PMS system, and 2.5 times and 1.6 times higher than those in the E/Na2SO4/MNZ(PCA) system, respectively. Different electrochemical characteristics, EPR spectra and radical quenching tests verified that the degradation of MNZ and PCA in the optimal system proceeded primarily through non-radical-dominated oxidation, involving electron transfer and 1O2 effect. The system also exhibited low energy consumption (0.215 kWh/m−3·order−1), broad operational pH range, excellent removal efficiency for water matrix, and low by-products toxicity, indicating its strong potential for practical applications. The ACC, with its super stable, low cost, and electrochemical activity, make it as a promising materials applicable in the E/PMS system for degradation of multiple pollutants. The study further elucidated the mechanism of pollutant interaction with electrode materials in terms of radical and non-radical transformation, providing fundamental insight into the application of this system for treatment of complex wastewater.

Efficient tetracycline degradation via flow-through peroxymonosulfate activation by dual heteroatom-doped wood-derived catalytic membrane

The widespread use of antibiotics in the medical industry and in animal husbandry has led to significant environmental pollution. Effective purification of high concentrations of tetracycline (TC) in practical pharmaceutical wastewater remains a substantial challenge. The integration of advanced oxidation with membrane separation technology shows great application potential. In this study, a P and N co-doped balsa wood membrane (PNWM) were fabricated using heteroatomic doped biochar material, aiming to synergize filtration and catalytic oxidation. The catalytic activity of the PNWM/peroxymonosulfate (PMS) system was systematically evaluated. Targeting TC as the pollutant, the PNWM/PMS system achieved a degradation efficiency exceeding 97 % within 30 min and a total organic carbon (TOC) removal efficiency of 63.9 %, surpassing the performance of unmodified wood-based membrane. These excellent results were attributed to the doping of N and P atoms, which increased surface defects and specific area, thereby enhancing the adsorption and degradation of TC by PNWM. The graphite N facilitated electron transfer, while pyridine N served as active sites for PMS activation. Additionally, the low electronegativity of the P formed electronic regions of varying intensities on the PNWM surface, contributing to PMS activation. The membrane process also enhanced mass transfer during the degradation process. Both radical (·OH, SO4·ˉ, O2·ˉ) and non-radical (1O2, electron transfer) pathways cooperated in TC degradation in PNWM/PMS system. Consequently, heteroatom-doped biochar film materials prepared through simple methods provide a promising approach for the effective treatment of refractory organic pollutants in wastewater.

Quantification of shedding propensity of polyester fabrics in the washing process

Global microplastic (MP) pollution from primary and secondary sources is partly caused by the growing trend towards the use of plastics. One of the most important factors for the persistence of MP in the environment is their high resistance to degradation. The washing process has been identified as a risk and source of various pollutants in wastewater and numerous studies have been published. This study focuses on three different polyester fabrics: woven, knitted and double-faced plush fabrics, which were washed under standard conditions with the reference detergent ECE A at 60 °C for 40 min. Different methods were used to quantify the released fragments in a 5- and 10-cycle wash, to analyse the samples gravimetrically and to characterise the wastewaters by physicochemical parameters and filter cake. The results proved that the structure of polyester fabrics plays a role in shedding, although most fragments were released from all polyester fabrics in the first washing cycles.

Rapid synthesis of novel S-scheme CaBi6O10/Bi2WO6 heterojunction film for efficient p-chlorophenol photocatalytic degradation

Efficient photocatalysts played a crucial role for degrading phenol pollutants in wastewater and vital for environmental remediation. In this study, a series of novel CaBi6O10/Bi2WO6 (CBO/BWO) step-scheme (S-scheme) heterojunction films were synthesized on the glass substrates through a facile and rapid spraying-calcination method. The CBO/BWO film demonstrated superior visible-light-driven catalytic activity for p-chlorophenol (4-CP) degradation within the fixed-bed photoreactor setup, compared with those of the single-component samples. Typically, the optimal 40CBO/BWO catalyst achieved 4-CP degradation efficiency of approximately 89.5 % after only 60 min under light exposure, attributed to the enhanced visible-light-absorption property and effective charge separation within the S-scheme heterojunction while maintaining high redox abilities among photoinduced carriers. Furthermore, the CBO/BWO catalyst displayed robust resistance to various metal cationic additives. Multiple key intermediates, such as phenol, dihydroxybenzene, benzoquinone and maleic acid, were identified in catalyzing process of 4-CP decomposition via oxidation processes involving hydroxyl radicals and superoxide radical as the primary active species. The above feasible photodegradation mechanism was elucidated and proven. Hence, this work offers valuable insights into developing efficient heterostructure photocatalysts for practical application of environmental remediation.

Nanofiber aerogel with layered array with structure coupled photothermal/magnetothermal effect for continuous seawater desalination

The solar evaporation is susceptible to intermittent solar irradiation as well as salt crystallization deposition on the surface severely limits the evaporation efficiency. In this work, subject to inspiration of the transpiration, groove array structure and antifouling performance of banana leaves, a multifunctional photothermal/ magnetothermal coupled three-dimensional(3D) aerogel evaporator with layer-by-layer array structure was prepared by blow-spun technology which can achieve mass produced. The unique super hydrophilic vertical array structure has multi-scale high-efficiency water transport channels and the SnSe-Fe3O4 evaporation layer realizes super hydrophobic self-cleaning and excellent photothermal and magnetothermal conversion performance, which can achieve all-weather seawater desalination. The vertical array structures facilitate the reflection and refraction of light and promote the seawater convection and salt crystals absorption coupling. It could improve the photothermal conversion efficiency and salt resistance of the evaporator. Which resulted in an evaporation rate of 2.53 kg m−2h−1 under 1 sun, with solar energy conversion efficiency of 105 % and the evaporation rate is about 4.54 kg m−2h−1 at a magnetic field. Furthermore, it could purify organic pollutants in industrial wastewater and use waste heat to generate electricity. This evaporator provides a new economical and environmentally friendly solution for seawater desalination and sewage treatment.

The impact of wastewater treatment plants on the composition and toxicity of pollutants in urban rivers in Nanjing, China

Widespread wastewater pollution is one of the biggest challenges threatening the ecological health of rivers. It is crucial to identify the toxic changes of effluents after entering urban rivers as well as the toxic substances in the complex chemical mixtures found in these urban rivers. This study used HepG2 cell line for cytotoxicity test to evaluate the ecological impact of effluents on urban rivers. Water samples were collected from the Xingwu River and Yunliang River in Nanjing, China. The bacterial communities in the lower reaches of urban rivers were altered due to the differences in total nitrogen and nitrate nitrogen. The complex chemical mixtures collected in the urban rivers were divided into 10 fractions, >100 chemicals were screened in each fraction. The substances with LC50 < 1000 mg/L were listed as toxic substances, and the number of toxic substances dominated the toxicity of urban rivers. Our study highlights toxicity as a comprehensive indicator for assessing river pollutants and reveals relationship between the number of toxic substance and river toxicity. These findings have direct implications for the monitoring and management of environmental stressors and the protection of aquatic organisms and human health.

Examining the photo catalytic potency of annealed and un-annealed ZnO and nickel doped ZnO for degradation of organic pollutants in waste waters

Water scarcity and pollution has increased the need for innovative and effective waste water treatment methods. The presented study aims to tackle this difficulty by synthesizing zinc oxide (ZnO) and nickel (Ni) doped ZnO to improve their photo catalytic capacity. This study examines wastewater treatment and organic pollutant breakdown using nanotechnology. The annealing increases photo catalytic activity by 65%, thereby enhancing efficiency. XRD shows that annealing decreased the average crystal size of pure ZnO and nickel doped ZnO (Ni:ZnO) i.e., for pure ZnO average crystal size is decreased from 23.90 to 20.90 nm and for Ni:ZnO, 34.39–28.65 nm. SEM shows that un annealed samples have agglomerates, while annealed samples are quasi-spherical. Using diffuse reflectance spectroscopy (DRS), the study examines how annealing affects optical band gap. Annealed Ni:ZnO has a band gap of 3.09 eV, which is smaller as compared to un annealed Ni:ZnO (3.18 e V). Similarly, the decline in energy band gap is observed for pure ZnO too. This study highlights the significant capacity of Ni:ZnO, for un annealed and annealed synthesis, to effectively meet the urgent requirements for waste water treatment. The extensive research conducted in this work enhances our comprehension of photo catalytic materials and underscores its potential for practical implementation in addressing waste water-related environmental issues.

Enhanced photocatalytic degradation of organic dyes by dual heterojunction of ZnO/NiWO4/V2C MXene

Multiphase composite catalysts can be designed for efficient photocatalytic treatment of organic pollutants in wastewater. Herein, the multiphase ZnO/NiWO4/V2C composite catalysts with dual heterojunction and hierarchically assembled nanoflower structures were constructed via a facile two-step hydrothermal and electrostatic self-assembly method. Utilizing NiWO4 and V2C as co-catalysts, these catalysts effectively degraded cationic dyes, methylene blue (MB) and rhodamine B (RhB) under visible light irradiation. The ZnO/NiWO4/V2C catalyst exhibited higher photocatalytic activity than ZnO in the degradation of MB and RhB, with rate constants of 0.0194 min−1 (a 7.43-fold enhancement) and 0.0176 min−1 (a 3.13-fold enhancement). The higher activity can be attributed to the construction of the double heterojunction using NiWO4 and V2C, which can facilitate efficient electron transport, improve charge separation efficiency, and provide more active sites. After four cycles, the ZnO/NiWO4/V2C catalyst still maintained good stability. Consequently, this work can offer a promising approach for environmental pollution treatment.

Production and characterization of nano-magnetic material through different red mud reduction processes

Red mud (RM), is an industrial waste deriving from the production of primary aluminium, with about 200 Mtons generated annually. In this work, the reduction of RM for obtaining magnetic products with particular chemical-physical characteristics has been explored. RM reduction was carried out in a semi-closed reducing environment at a high processing temperature (750–1100 °C) in the presence of carbon-rich ash (CA) resulting from a commercial pyro-gasification plant and by using an H2 atmosphere. All the materials were characterized by elemental analysis, XRD diffraction technique, SEM/EDX microscopy, thermogravimetry and infrared spectroscopy. The materials obtained under the different conditions have in common the presence of small iron-magnetic domains (with different iron oxidation states), in the order of hundreds of nanometres, and by the ferro-magnetic or paramagnetic response to an external magnetic field. In particular, the material pre-treated with HCl (enriched in iron) and reduced with H2 showed very good magnetic responses, more iron in reduced oxidative states showing high ferro-magnetic responses to the external field. The synthesised materials are quite differents each others and appear to have several potential fields of application, as sorbents for specific wastewater pollutants, as materials for CO2 capture, for catalysis and (bio)sensing applications. Nevertheless, the high interconnection between the magnetic and non-magnetic phases limit the direct separation or the iron enrichment. Further efforts should be focused on the functional studies and subsequent LCA and LCC analyses.

Effects of LED lights and cytokinin on the phytotreatment of simulated swine wastewater by Azolla spp.: Pollutant removal and biomass valorization

Phytoremediation is an eco-friendly and affordable option for tackling wastewater pollutants. The study focused on how light-emitting diodes (LED) light exposure, measured by intensity and duration (photoperiod), along with cytokinin, impacts Azolla microphylla's simulated swine wastewater treatment performance and biomass production. Under optimal treatment conditions, high removals of COD (89.2 % to 90.8 %), N-NH4+ (72.6 % to 91.2 %), N-NO3- (84.4 % to 88.6 %), Cu (75.4 % to 86.4 %), sulfamethoxazole (77.0 % to 79.0 %), P-PO43- (54.1 % to 59.9 %) and DOC (67.4 % to 71.3 %) while Zn presented a more moderate reduction (2.0 % to 9.7 %). Biomass productivity reached up to 34.8 t ha-1 yr-1. Protein production accounted for 23 % to 27 % of dry weight, while lipids ranged from 20 % to 34 % of dry biomass. Carbohydrate content varied from 8 % to 28 % of fresh weight. Higher light intensities, with both high or low values of photoperiods, and low concentrations of cytokinin were identified as optimal conditions for removal of almost all pollutants. However, pollutant removal was impacted differently by LED light and cytokinin concentration. In treatment conditions with the shortest photoperiods (8 h), the lowest residual Cu and Zn concentrations, whereas with longer photoperiods (24 h), the lowest residual concentrations of N-NH4+ and P-PO43- concentrations were recorded. On the other hand, SMX was the only parameter in which cytokinin had a clear influence on its removal, with the lowest residual concentration observed under 8-hour photoperiods combined with the lowest tested cytokinin concentrations (0.3 mg L-1). For residual COD and N-NO3-, no discernible pattern was evident for any of the analyzed factors. Therefore, the study demonstrates the potential for treating simulated swine wastewater using Azolla microphylla, aligned with its ability to produce biomass rich in high-value compounds.

Anelosimuseximius bioinspired ZnO nano cobwebs for environmental remediation of drugs and endocrine disruptors from water

The pollution of wastewater with pharmaceuticals and endocrine-disrupting chemicals (EDCs) in populated areas poses a growing threat to humans and ecosystems. To address this serious problem, various one-dimensional (1D) hierarchical ZnO-based nanostructures inspired by Anelosimus eximius cobwebs were developed and successfully grown on a glass substrate through simple hydrothermal synthesis. The nanorods (nr) obtained during primary growth were chemically etched with KOH (ZnOnr-KOH), followed by the secondary growth of nano cobweb-like (ncw) structures using polyethyleneimine (ZnOnr/ncw). These structures were further decorated by the photoreduction of Ag nanoparticles (ZnOnr/ncw/Ag). The feasibility of ZnO-based 1D nanostructures to remove pollutants was demonstrated by degrading commonly prescribed pharmaceutical drugs (diclofenac and carbamazepine) in a miniature cuvette reactor. The photocatalytic activities for drug degradation generally decreased in the order ZnOnr/ncw/Ag > ZnOnr/ncw > ZnOnr-KOH. Additionally, the suitability of the samples for scaling up and practical application was demonstrated by photocatalytic degradation of the hormone estriol (E3) in a flow-through photoreactor. The photocatalytic degradation efficiency of E3 followed the same trend observed for drug degradation, with the complete elimination of the endocrine disruptor achieved by the best-performing ZnOnr/ncw/Ag within 4 h, due to optimized charge transfer and separation at the heterostructure interface.

One-Step Self-Assembled WO3/rGO Microspheres Photoanode Assembled Efficient Photocatalytic Fuel Cells for Simultaneous Organic Pollutant Degradation and Electricity Generation.

Photocatalytic fuel cells (PFCs) present a promising and environmentally friendly approach to simultaneously treat organic pollutants in wastewater and electricity generation. The development of photoanodes with high light absorption and carrier mobility is essential for enhancing the performance of PFCs but remains challenging. Herein, a one-step self-assembly strategy was adopted to develop flower-like WO3/rGO microspheres for PFC devices. Attributed to the abundant surface-active sites, enhanced light harvesting, and efficient separation of photogenerated charge carriers, the WO3/rGO photoanode demonstrated superior rhodamine B (RhB) degradation rate (90% in 2 h), maximum power density (4.74 μW/cm2), and maximum photocurrent density (0.096 mA/cm2), 1.4, 2.4, and 4.0 times higher than the corresponding pure WO3 photoanode, respectively. Density functional theory (DFT) calculations reveal that the built-in electric field formed between the interface of WO3 and rGO promotes the transfer of photogenerated electrons from WO3 to rGO, thus exerting a significant impact on improving the migration and separation of photoinduced charge carriers. Moreover, by combining experimental and theoretical results, a complete PFC operation mechanism for the PFC system was proposed. This study focuses on the strategy of constructing rGO-doped photocatalysts to enhance the interfacial charge transfer mechanism, providing a promising approach for the development of high-performance photoanodes in PFC systems.

A multipurpose organometallic pyridyl Schiff base-modified poly(divinylbenzene) matrix for the catalytic removal of nitrophenols and polycyclic pollutants

Widespread organic pollutants in wastewater include toxic nitrophenols and polycyclic molecules. Here, we aim to develop a single multipurpose catalyst capable of degrading these structurally dissimilar contaminants by preparing a pyridyl Schiff base-functionalized poly(divinylbenzene) porous organic polymer displaying Ag complexes (PDVB-PA@Ag). PDVB-PA@Ag hydrogenated 4-nitrophenol (4-NP) efficiently to valuable and less toxic 4-aminophenol with an optimized reaction rate of 45.4 × 10−3 s−1 and apparent activation energy of only 20.1 kJ mol−1. The same catalyst also readily hydrogenated the isomers of 4-NP as well as nitrophenols with several nitro groups and halogenated nitrophenols with reaction rates ranging from 4.0 to 20.3 × 10−3 s−1. In addition, the multiuse PDVB-PA@Ag was capable of carrying out a second type of reaction and degraded multiple polycyclic dyes commonly found in wastewater including auramine O, basic blue 17, aniline blue, and malachite green through Fenton-like oxidation. PDVB-PA@Ag-based degradation processes for the four toxic dyes evaluated were efficient with pseudo-first order reaction rates varying between 1.2 × 10−2 to 3.7 × 10−2 min−1. By coordinating an array of versatile catalytic complexes on an extensive and stable porous support, PDVB-PA@Ag was made highly performant at completing different essential water-cleaning processes.

Generation of H2O2 via simultaneous treatment of cotton and organic pollutants in textile wastewater

The textile industry is essential for human life but generates significant amounts of waste cotton and alkaline dye wastewater. These pollutants are difficult to separate and treat, causing numerous environmental issues. Traditional methods struggle to deal with the combined pollution without additives. In this study, we developed a simple hydrothermal process to convert waste cotton and dye wastewater into a non-metal catalyst. This catalyst can degrade dyes using oxygen from the air. Remarkably, it produces a substantial amount of H2O2 after degrading the dyes. This demonstrates that we utilized waste cotton present in textile wastewater as a catalyst precursor and abundant oxygen as an oxidant to convert dye wastewater into valuable H2O2. We also used commercially available cotton cloth as a raw material and achieved good results. Under the optimized conditions, 96 % of the dye was degraded within 4 h, generating 252 μM of H2O2 simultaneously. Additionally, the catalysts performed better under alkaline conditions, with the dye degradation rate increasing by 33 % compared to neutral conditions. This is ideal for alkaline textile mill wastewater. Therefore, our work provides a novel method for the treatment of cotton waste and dyes in textile mills and has broad application prospects.

Preparation of Polymeric Aluminum Chloride-Loaded Porous Carbon and Evaluation of Its Pb2+ Immobilization Mechanisms in Soil

In recent years, the remediation of heavy metal-contaminated soils has attracted great attention worldwide. Previous research on the removal of toxic heavy metals from wastewater effluents through adsorption by typical solid wastes (e.g., fly ash and coal gangue) has mainly focused on the control of wastewater pollutants. In this study, a coal gangue (CG) by-product from Hancheng City was used as a raw material to prepare polymeric aluminum chloride-loaded coal gangue-based porous carbon (PAC-CGPC) by hydrothermal synthesis. This material was subsequently employed to assess its performance in mitigating Pb2+ in soils. In addition, the effects of the pore structure of the prepared material on the adsorption rates, adsorption mechanisms, and plant root uptakes of soil Pb2+ were investigated in this study. The raw CG and prepared PAC-CGPC materials exhibited specific surface areas of 1.8997 and 152.7892 m2/g, respectively. The results of adsorption kinetics and isotherms indicate that the adsorption of Pb2+ based on PAC-CGPC mainly follows a pseudo-second-order kinetic model, suggesting that chemisorption may be the dominant process. In addition, the adsorption isotherm results showed that the Freundlich model explained better the adsorption process of Pb2+, suggests that the adsorption sites of lead ions on APC-CGPC are not uniformly distributed and tend to be enriched in APC, and also shows the ion exchange between aluminum and lead ions. The thermodynamic model fitting results demonstrated the occurrence of spontaneous and exothermic PAC-CGPC-based adsorption of Pb2+, involving ion exchange and surface complexation. The effects of the PAC-CGPC addition on soybean plants were further explored through pot experiments. The results revealed substantial decreases in the Pb2+ contents in the soybean organs (roots, stems, and leaves) following the addition of the PAC-CGPC material at a dose of 3% compared with the control and raw CG groups. Furthermore, the addition of the PAC-CGPC material at a dose of 3% effectively reduced the bioavailable Pb2+ content in the soil by 82.11 and enhanced soybean growth by 15.3%. These findings demonstrated the inhibition effect of the PAC-CGPC material on the translocation of Pb2+ in the soybean seedlings. The modified CG adsorbent has highly pore structure and good hydrophilicity, making it prone to migration in unsaturated soils and, consequently, enhancing Pb2+ immobilization. This research provides theoretical support for the development of CG-based materials capable of immobilizing soil pollutants.

Air Pulsed-Corona discharges for degradation of emerging pharmaceutical pollutants in water and toxicity by-products control

The present study, based a tip-to-plane pulsed corona setup, examined the effects of tip-water distance, radius of curvature of electrode tip, and pulse voltage on the production of liquid-phase RONS used an indicator of degradation performance. Measurements of long-lived RONS species (nitrates, nitrites and H2O2) in deionized water were specifically analyzed. The optimum conditions were used for the removal of a high concentration (500 mg/L) of 4-acetaminophen (i.e. paracetamol) with study of oxidation by-products and their toxicity. The results showed that optimum RONS production in the liquid phase occurred for a short gap distance (4 mm), a tip curvature radius of 100 μm and a pulsed voltage of 10 kV and 10 kHz corresponding to an energetic corona spark regime which is characterized by optical emission spectroscopic measurements. Using these optimal corona discharge parameters, the study showed that after 30 min of exposure to the air plasma, 60 % removal efficiency was achieved at an initial paracetamol concentration of 500 mg/L based on HPLC-DAD sample analysis. GC–MS and LC-MS analysis of treated samples enabled us to identify and characterize two new by-products not previously identified in the literature: N-(4-(4-hydroxyphenylamino) phenyl) acetamide (m/z: 242) and N-(4-aminophenyl) acetamide (m/z: 150), most of which were nitrogen compounds. Further analysis of the toxicity of these by-products to the human cell line (HEK-293) demonstrated that the treated water was not toxic.Overall, these results show that the CDP system is one of the best techniques for treating highly polluted wastewater.

Effect of cephalexin on chlorophyll and carotenoid content of Chlorella pyrenoidosa-2378 and its biodegradation in BG-11 medium

Cephalexin (CFX), a β-lactam antibiotic which is identified for the treatment of different disease infections, has been reported as a micropollutant in wastewater released from sewage, hospital, or pharmaceutical industries. Chlorella pyrenoidosa-2378, a green microalgal strain, is recognized for its degradation ability against wastewater pollutants and the potential of the biomass it produces. In this present study, the cultivation process of Chlorella pyrenoidosa-2378 strain with CFX concentration of 50 mg/L, 100 mg/L, 150 mg/L, and 200 mg/L added to its culture medium labeled as test I, test II, test III, and test IV, respectively, is the process being observed for evaluation of its degradation ability and as sustainable approach for antibiotic degradation. chlorophyll a in test IV, chlorophyll b in test III, and carotenoid content in test I were observed to be higher in amount than control by 0.775 mg/L, .069 mg/L, and 0.356 mg/L, respectively. Using the HPLC method, the total removal efficiency was observed to be 79.09%, 86.26%, 89.62%, and 88.03% against 50, 100, 150, and 200 mg/L concentrations of CFX, respectively. The observations that C. pyrenoidosa-2378 remained stable while being used as an alternative bioremediation method, provide an alibi for its novelty and potentiality to be used commercially for biomass production and at industrial scale for degradation.Graphical

Potential for nutrients reuse, carbon sequestration, and CO2 emissions reduction in the practice of domestic and industrial wastewater recycling into agricultural soils: A review

This review assesses the feasibility of reusing treated wastewater for irrigation in agricultural soils as a strategy for nutrients recycling and mitigation of CO2 emissions. Through a literature review, it was examined wastewater sources enriched with carbon and nutrients, including municipal wastewater and associated sludge, vinasse, swine wastewater, as well as wastewater from the food industry and paper and pulp production. The review also explores the dynamics of organic matter within the soil, discussing the aspects related to its potential conversion to CO2 or long-term storage. It was found that industrial wastewaters, owing to their higher organic matter and recalcitrance, exhibit greater potential for carbon storage. However, the presence of pollutants in wastewater necessitates careful consideration, particularly concerning their impact on soil quality. Toxic metals, microplastics, and organic compounds emerged as significant contaminants that could accumulate in the soil, posing risks to ecosystem health. To mitigate the environmental impacts, it was evaluated various wastewater treatment technologies and their associated carbon emissions. While advanced treatments may effectively reduce the contaminant load and mitigate soil impacts, their adoption is often associated with an increase in CO2 emissions. Membrane bioreactors, microfiltration, ultrafiltration, and up-flow anaerobic sludge blanket reactors were identified as promising technologies with lower carbon footprints. Looking ahead, future research should aim to enhance the understanding of carbon dynamics in soil and validate the environmental impacts of treated wastewater disposal. Despite remaining uncertainties, the literature indicates a positive outlook for wastewater recycling in soil, offering a viable strategy for carbon storage and mitigation of greenhouse gas emissions.

Perceived Effect of Shipborne Sewage Discharge on Water Quality of Apapa Sea Port

The Apapa Sea Port in Lagos, Nigeria, faces significant environmental concerns due to shipborne sewage discharge. Over 3 billion tons of sewage are discharged annually, posing health risks and causing disease outbreaks. Understanding this relationship is crucial for developing policies to protect marine environments and port operations. The study investigates the perceived effects of sewage wastewater pollution on the marine environment, focusing on Apapa Port, Nigeria’s largest and busiest port. The study used a sample of 475 individuals, with a stratified frame of 323 respondents, resulting in a sample size of 245 using Yaro Yamane’s formula. Descriptive statistical methods were used to summarize and interpret data, with a mean score of 2.5 as the threshold for classification. Inferential statistics, including ANOVA and regression analysis, were used to test the research hypotheses. The results shown that the perceived impact of sewage pollution on water quality, with findings showing a strong awareness and concern among port personnel regarding its deleterious effects, including eutrophication (mean rating: 3.825), harmful algal blooms (mean rating: 3.921), habitat degradation (mean rating: 3.868), and waterborne diseases (mean rating: 4.018). The Hypotheses testing confirmed that sewage discharge significantly impacts the study area (p-value = 0.048) and that the implementation of MARPOL Annex IV has a significant influence on pollution levels (p-value &lt; 0.05). The study concludes with recommendations to improve treatment processes, enforcement mechanisms, infrastructure, and stakeholder collaboration to ensure compliance and protect the marine ecosystem at Lagos Port, among many others. Keywords: Apapa seaports, sewage, shipborne, pollution, waste management.

Synthesis of phthalocyanine/C3N4 structures and investigation of photocatalytic activities in the oxidation reaction of 4-nitrophenol

Photocatalytic oxidation is an advanced oxidation technique widely preferred for the removal of pollutants in wastewater. In this work, paramagnetic metallo-phthalocyanines EB2 and EB3 (Co(II)phthalocyanine and Cu(II)phthalocyanine) have been synthesized and characterized. They were interfaced with C3N4 (graphitic carbon nitride) to prepare metallophthalocyanines/C3N4 structures (EB2-C3N4 and EB3-C3N4) using ultrasonic methods. New structures were identified with FT-IR, SEM and TGA. The photocatalytic performances of EB2-C3N4 and EB3-C3N4 for reaction with p-nitrophenol (p-NP) were established. The product selectivity for industrially important benzaldehyde was 85.1% for EB2-C3N4 and 80.6% for EB3-C3N4. EB2-C3N4 showed good potential for p-NP photocatalyic oxidation with high turn-over number (TON) and turn-over frequency (TOF) (390 and 1565) over 15 min. Upon excitation of EB2-C3N4 and EB3-C3N4 with light, 4-nitrophenol was easily reduced to hydroquinone, prompted by electron transfer from C3N4 to phthalocyanine and from phthalocyanine to 4-nitrophenol. Computational investigations were used to determine the energies of the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO) of EB2, EB3 and C3N4.