Oxygen Demand Carbon Research Articles

Breakdown cost and recycling processes of Bentonite/TiO2 quantum dots of photo and solar degradation of Congo Red dye and industrial dyes wastes

This research presents the preparation, characterization, and application of a novel bentonite- TiO2 quantum dot (Bent/TQ) nanocomposite for the efficient photodegradation of Congo Red dye, a common pollutant in industrial wastewater. The composite was prepared via a co-precipitation method followed by calcination, which facilitated the uniform dispersion of TiO2 quantum dots within the bentonite matrix. The resulting material exhibited a high specific surface area of 205.45 m2/g and an optimized band gap of 3.15 eV, making it suitable for visible light photocatalysis. The photocatalytic efficiency of Bent/TQ was evaluated under both xenon lamp irradiation and natural sunlight. The composite demonstrated a significant degradation rate constant of 23.35 × 10⁻³ s⁻1, which is comparable to that of pure TiO2 quantum dots (28.86 × 10⁻³ s⁻1). Mechanistic studies revealed that the primary active species responsible for the degradation were hydroxyl radicals (•OH), generated through the interaction of photogenerated electron-hole pairs with H2O molecules and molecular oxygen. Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) analyses were employed to assess the mineralization efficiency of the composite. The Bent/TQ catalyst achieved a COD removal efficiency of 84.5% and a TOC reduction of 76.2% after 240 minutes of irradiation under natural sunlight. Reusability tests indicated that the photocatalyst retained approximately 80% of its original efficiency after seven consecutive cycles, though a slight decline was observed due to particle agglomeration under prolonged light exposure. The economic analysis suggested that the use of Bent/TQ nanocomposites could reduce operational costs by 29.12% compared to conventional TiO2-based systems, making it a cost-effective solution for large-scale wastewater treatment. This work highlights the potential of Bent/TQ nanocomposites as sustainable and efficient photocatalysts for environmental remediation, with future efforts aimed at enhancing their long-term stability and expanding their applicability to a broader range of pollutants.

Innovative RGO-bridged S-scheme CuFe2O4@Ag2S heterojunction for efficient Sun-light-driven photocatalytic disintegration of Ciprofloxacin

Antibiotics contamination in water bodies poses a significant threat to public health and the environment, necessitating advanced methods for their removal from wastewater. In response to this issue, developing a novel magnetic nanocomposite (RGO/CuFe2O4@Ag2S) as an efficient photocatalyst for the degradation of pharmaceuticals like ciprofloxacin (CIP) is of great importance. The synthesized nanocomposite underwent comprehensive characterization to elucidate its crystalline structure, chemical bonding, surface morphology, elemental composition, internal structure, optical properties, surface area, particle size distribution, and magnetic properties. Under optimized conditions (pH=9, nanocomposite dose =0.5 g/L, CIP concentration of 20 mg/L, and duration of 200 minutes), the nanocomposite demonstrated complete degradation of CIP. Moreover, post-treatment analysis revealed significant reductions in total organic carbon (TOC) and chemical oxygen demand (COD) of 70.08% and 85.08%, respectively, indicating extensive mineralization of the antibiotic. Mechanistic investigations revealed a unique S-scheme heterojunction in the RGO/CuFe2O4@Ag2S nanocomposite, where RGO acts as an electronic bridge between CuFe2O4 and Ag2S. This innovative architecture facilitates efficient charge separation and transfer, significantly enhancing the photocatalytic activity. Reusability tests demonstrated the robust nature of the photocatalyst, with only a modest 6% decline in efficiency after six consecutive cycles. To further assess the system's effectiveness in real-world applications, its performance was evaluated in treating pharmaceutical wastewater. The biodegradation efficiency was quantified by measuring the Average Oxidation State (AOS) and Carbon Oxidation State (COS) of the wastewater samples before and after treatment.

Radiolysis performance of ibuprofen using ionizing processes: kinetics and energy consumption

ABSTRACT Ionizing technologies are used for disinfection and treatment of different industrial wastewaters. For this purpose, the radiolytic degradation of ibuprofen (IBP), selected within the main detected pharmaceuticals in different water locations with different concentrations, was investigated. Irradiation was performed with a gamma irradiator (60Co) and with electron beam accelerator. The degree of ibuprofen degradation was monitored following the evolution of its absorbance, the residual concentration by HPLC, carbon oxygen demand and total organic carbon. The degradation of IBP was higher than the removal of TOC or COD and reached 95% according to residual concentration. This pollutant (at 0.1 mM) was totally degraded when irradiated at 3 kGy and needed higher doses (7–10 kGy) for the highest concentrations (0.8–1 mM). The addition of 1 mM of persulfate ion remarkably enhanced IBP degradation by around 2 and 2.8 times for 5 and 10 kGy, respectively. Pseudo-first-order reaction kinetics could be used to depict the degradation process of IBP in all conditions. Electrical energy per order (EEO) was estimated under various conditions. The smallest EEO was obtained when gamma radiation and persulfate ion were combined. The possible degradation pathways of IBP were proposed. The results achieved in this study can be used to optimize large-scale application of nuclear techniques in water treatment in particular in treating pharmaceutical effluents.

Synergizing MBR and MCDI systems as a sustainable solution for decentralized wastewater reclamation and reuse

Decentralized wastewater reclamation and reuse systems have drawn much attention due to their capability for reducing the energy demand for water conveyance and reclaiming wastewater for local re-use. While membrane bioreactor (MBR) stands as a mature technology offering comprehensive solid and liquid separation, membrane capacitive deionization (MCDI) presents a promising avenue for ion separation. Unfortunately, MCDI has seldom been incorporated into decentralized wastewater reclamation and reuse systems. This study aims to exemplify the design and the operation of the synergistic integration of MBR and MCDI system with a practical capacity of 1 m3 d− 1, showcasing its efficacy in reclaiming and reusing water at regional level. The integrated system demonstrated significant high removal of total organic carbon (from 97 to 2 mg L− 1) and chemical oxygen demand (COD, from 218 to < 3 mg L− 1). Meantime, nearly complete transformation (approximately 91%) of NH3 to NO3− within the MBR effluent was observed with a hydraulic retention time of 4.3–4.8 h and a food-to-microorganism of 0.15–0.20 kg COD kg− 1 MLSS d− 1 which can be further removed through the MCDI system (> 92% TN removal). A significant milestone of MCDI unit was reached with the remarkable removal efficiency of total ions (93%) and water recovery (80%) using a stop-flow regeneration approach coupled with an optimized voltage of 2.0 V. The MCDI unit not only proved its high stability but also featured low energy consumption (0.44 kWh m− 3). Overall, synergizing MBR and MCDI systems emerges as a sustainable and effective solution for decentralized wastewater reclamation and reuse, contributing to a more environmentally friendly and resource-efficient water management paradigm.

Study of Using a Phyto-nanosynthesis of Silver and Portulaca Oleracea Plant Extracts in Petroleum Spots Treatment

Petroleum spots has become a major global problem not only in terms of its increase, but also how it is treated, recycled or utilized. It contains suspended and dissolved solids, hydrocarbons and many types of organic matter and heavy metals. The reuse of petroleum spots faces the problem of removing organic pollutant compounds before discharging them into any natural stream. in this study, natural nano –coagulant material was used and their efficiency in removing turbidity, Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) from petroleum spots were compared. The study was conducted in the laboratories of the Ecology Sciences Department, University of Kufa, Iraq in 2022. By synthesizing Phyto-nanosilver as a Phyto-nano silver from Leaves of Portulaca oleracea plant extracts used to reduce turbidity and organic pollutants of the petroleum spots. Jar test experiments showed that 0.5 mg / L Phyto-nanosilver dose can remove 95.5 % of (COD), 87.3% of TOC and 85.2 % from turbidity. Also, removal of P. oleracea plant extracts in the 1 and 0.5 mg/L dose can removed turbidity, COD and TOC content of 91.9%, 87.5 % and 82.4% respectively of the petroleum spots. Moreover, when using the nano-sliver only, removal of TOC, COD, and turbidity would reach 75.3%, 80.4%, and 81.3 %, respectively. The results of the research showed the efficiency of Phyto-nano silver materials in treating and depositing pollutants without harming the environment.

Once through continuous mode electrocoagulation for tannery wastewater remediation: Process optimization and performance evaluation

The treatment of wastewater from tannery industries poses significant challenges due to high levels of tannic acid and chemical oxygen demand (COD), along with low biodegradability. To address this issue, we conducted a study focusing on the use of Electrocoagulation (EC) as a treatment process for synthetic tannery wastewater. Iron (Fe) electrodes have been used as anode and cathode as well. The electrodes size (7 cm × 7 cm) has been used in this process. The investigation of removal efficiencies entailed the assessment of total organic carbon (TOC) and chemical oxygen demand (COD) as indicators of organic contaminant levels within the wastewater. The influence of current density, pH, flowrate, and time on the treatment was measured. At a current density of 51 A/m2 with 83.54 % of COD removal and 27 % of TOC removal were observed. The maximum COD removal was found at pH 4.93, flowrate 5 ml/min, current 0.953 A and time 115 min. The current investigation demonstrated the efficacy of the electrocoagulation process in reducing both total organic carbon (TOC) and chemical oxygen demand (COD) levels in synthetic tannery wastewater.

Redox-switchable microemulsions with efficient phase separation and surfactant recycling

HypothesisSwitchable microemulsions (MEs) are those capable of adaptively responding to the action of internal or external stimuli. For redox-switchable MEs to obtain high-efficiency phase separation and surfactant recycling, it may be one of the keys to adequately turn off the interfacial activity of surfactants and reduce the solubility of the closed surfactants in the oil phase. ExperimentsMonophasic MEs consisting 11-butylselanyl-undecyl sulfate sodium (C4SeC11SO4Na), n-butanol, n-octane, and water were fabricated using the pseudo-ternary phase diagram method. Their structural features and droplets size were characterized by conductivity, dynamic light scattering (DLS) and cryogenic transmission electron microscopy (cryo-TEM), respectively. The redox response of MEs was studied using a combination of visual observations and DLS, cryo-TEM, nuclear magnetic resonance (NMR) and thin-layer tomography. The efficient recycling of C4SeC11SO4Na from a well-emulsified eluent is conceptually demonstrated. FindingsThe reversible transition between C4SeC11SO4Na and C4SeOC11SO4Na is achieved under the alternating action of H2O2 and N2H4, by which C4SeC11SO4Na-based monophasic MEs are able to efficiently demulsify and regenerate, respectively, regardless of their type. After H2O2-induced demulsification of the MEs, C4SeOC11SO4Na can be efficiently recycled with the water phase. We hope that such a redox-switching method may benefit some technological applications. For example, it offers exciting possibilities for simultaneous recycling C4SeC11SO4Na and removal of oil from a well-emulsified eluent. Around 97.1 ± 0.3 % of C4SeC11SO4Na could be recycled over five cycles with no apparent loss. After a simple and conventional treatment with anion-exchange resin and active carbon, the total organic carbon and chemical oxygen demand of the waste water were 17.4 ± 2.8 and 26.2 ± 1.4 mg/L, respectively.

The Role of Macronutrients in Chronic Obstructive Pulmonary Disease: A Review

The incidence of chronic obstructive pulmonary disease (COPD) is rising and is still regarded as one of the challenging medical issues. Regardless of the main relationship between tobacco smoking and toxic particle exposure with COPD, factors like nutritional status also play an important role in COPD progression and outcome, as the factor is an adaptable aspect. Malnutrition, sarcopenia, and obesity are nutritional problems that are often encountered in COPD patients. Macronutrients, namely carbohydrates, fat, and protein, support the adjunctive treatment options for COPD. The ideal dietary pattern includes low carbohydrates, medium fats preferably polyunsaturated fatty acids (PUFA), and high proteins to improve COPD symptoms, preserve muscle mass, and delay disease progression. High carbohydrate intake might also increase the respiratory quotient (RQ) which results in higher carbon dioxide (CO2) production and oxygen (O2) demand compared to fat and protein intake. Daily calorie intake should be adjusted to personal nutritional status. Higher calories in malnourished, sarcopenic patients and targeted weight loss in obese patients show improvements in lung function, frequency of exacerbations, and hospitalization rate. In obese individuals with COPD, however, maintaining a slightly higher body mass index (BMI) of 25-30 kg/m2 was associated with lower mortality. This literature review summarized the significant role of macronutrients in COPD patients and the practical approach to macronutrient intervention in individuals with different nutritional statuses.

Recovery of Chromium and Two Solvents (Dichloromethane-DCM Tetrachloroethane-TCE) Using Nanofiltration and Reverse Osmosis Membranes from Leather Industry Wastewater

In this study, for removal of the leather industry pollutants and to recovery of chromium (Cr), dichloromethane (DCM) and tetrachloroethane (TCE) two sequential nanofiltration (NF) (NF90 and NF270) and two reverse osmosis (RO) (BW30 and SW30) reactor membranes were used. The membrane surface properties were investigated by Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) and Scanning Electron Microscopy (SEM). The permeate of the SW30 reverse osmosis exhibited high removals varying between 98% and 99% for sodium ion (Na+ ), potassium ion (K+ ), magnesium ions (Mg2+), calcium ions (Ca2+), total chemical oxygen demand (CODtotal), dissolved chemical oxygen demand (CODdis), dissolved organic carbon (DOC) and inert chemical oxygen demand (inert COD), Chromium (Cr3+ ), Dichloromethane and Tetrachloroethane. In the NF90 nanofiltration process lower removals were detected (96%-97%) for all pollutants mentioned above. The effluent of reverse osmosis with a BW30 membrane match to the Turkish Water Pollution Control Regulation rules for treated water discharged to the receiving environment while SW30 reverse osmosis membrane was perfect for ultimate treatment of the pollutants present in the leather industry discharges. From the concentrate of the SW30 reverse osmosis, 945 mg/l chromium, 460 mg/l dichloromethane and 360 mg/l tetrachloroethane were reused. The performance and recoveries of Cr and two solvents (DCM and TCE) data in NF and RO membrane reactors were evaluated with Artificial Neural Network (ANN) process and Kruskal Wallis test statistic coupled with Mann-Whitney U statistic in this study.

New insights into toxicity reduction and pollutants removal during typical treatment of papermaking wastewater

Papermaking wastewater contained various of toxic and hazardous pollutants that pose significant threats to both the ecosystem and human health. Despite these risks, limited research has addressed the detoxification efficiency and mechanism involved in the typical process treatment of papermaking wastewater. In this study, the acute toxicity of papermaking wastewater after different treatment processes was assessed using luminousbacteria, zebrafish and Daphnia magna (D. magna). Meanwhile, the pollution parament of the corresponding wastewater were measured, and the transformation of organic pollutant in the wastewater was identified by three-dimensional fluorescence and other techniques. Finally, the possible mechanism of toxicity variation in different treatment processes were explored in combination with correlation analyses. The results showed that raw papermaking wastewater displayed high acute toxicity to luminousbacteria, and exhibited slight acute toxicity and acute toxicity effect to zebrafish and D. magna, respectively. After physical and biochemical processes, not only the toxicity of the wastewater to zebrafish and D. magna was completely eliminated, but also the inhibitory effect on luminousbacteria was significantly reduced (TU value decreased from 11.07 to 1.66). Among them, the order of detoxification efficiency on luminousbacteria was air flotation > hydrolysis acidification > IC > aerobic process. Correlation analyses revealed a direct link between the reduced of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) and the detoxification efficiency of the different processes on the wastewater. In particular, the removal of benzene-containing aromatic pollutant correlated positively with decreased toxicity. However, the Fenton process, despite lowering TOC and COD, increased of the acute toxicity of the luminousbacteria (TU value increased from 1.66 to 2.33). This may result from the transformation generation of organic pollutant and oxidant residues during the Fenton process. Hence, oxidation technologies such as the Fenton process, as a deep treatment process, should be more concerned about the ecological risks that may be caused while focusing on their effectiveness in removing pollutant.

A concise review on wastewater treatment through microbial fuel cell: sustainable and holistic approach.

Research for alternative sources for producing renewable energy is rising exponentially, and consequently, microbial fuel cells (MFCs) can be seen as a promising approach for sustainable energy production and wastewater purification. In recent years, MFC is widely utilized for wastewater treatment in which the removal efficiency of heavy metal ranges from 75-95%. They are considered as green and sustainable technology that contributes to environmental safety by reducing the demand for fossil fuels, diminishes carbon emissions, and reverses the trend of global warming. Moreover, significant reduction potential can be seen for other parameters such as total carbon oxygen demand (TCOD), soluble carbon oxygen demand (SCOD), total suspended solids (TSS), and total nitrogen (TN). Furthermore, certain problems like economic aspects, model and design of MFCs, type of electrode material, electrode cost, and concept of electro-microbiology limit the commercialization of MFC technology. As a result, MFC has never been accepted as an appreciable competitor in the area of treating wastewater or renewable energy. Therefore, more efforts are still required to develop a useful model for generating safe, clean, and CO2 emission-free renewable energy along with wastewater treatment. The purpose of this review is to provide a deep understanding of the working mechanism and design of MFC technology responsible for the removal of different pollutants from wastewater and generate power density. Existing studies related to the implementation of MFC technology in the wastewater treatment process along with the factors affecting its functioning and power outcomes have also been highlighted.

Tannic acid enhanced the removal of Phaeocystis globosa from seawater by Fe (II) activated persulfate

The frequent outbreaks of Phaeocystis globosa (P. globosa) blooms in coastal areas have seriously threatened nuclear power safety. In this study, tannic acid (TA) was used to accelerate the removal of P. globosa from seawater by Fe (Ⅱ) activated persulfate (PS). In comparison with the Fe (Ⅱ)-PS system, the higher removal efficiency of P. globosa was obtained in the TA-Fe (Ⅱ)-PS system (91.2% vs 67.5%). The removal efficiency of fluorescence value, chlorophyll a, turbidity and total organic carbon (TOC) reached up to 90.1%, 91.2%, 61.8% and 51.6% with the addition of 10 mg L−1 of TA, 100 mg L−1 of Fe (Ⅱ) and 240 mg L−1 of PS in 420 min. The flocs images confirmed that TA played a dual role in regulating Fe (Ⅱ) concentration and activating PS, which facilitated the pre-oxidation of algae cells. Finally, the inactivated P. globosa settled to the bottom with the iron mineral flocs. In addition, positive environmental impacts were also validated due to the decrease in total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD). The findings demonstrated that TA-Fe (Ⅱ)-PS system is a promising candidate for the removal of P. globosa from seawater.

Fabrication of Ag/WO3/g-C3N4 composites for the photocatalytic degradation of harmful dyes

In the present work, it is noticed that the synthesis of photocatalytic bare and composite materials: i) bare graphitic carbonitride g-C3N4 (GCN), ii) modified with tungsten oxide WO3/g-C3N4 (WGCN), and iii) with both tungsten oxide and silver nanoparticles WO3/Ag/g-C3N4 (WAgGCN), by three different methods: calcination, precipitation, and ultrasonication. Also, their photocatalytic efficiencies were evaluated towards the photodegradation of different dyes under visible, UV, and sunlight irradiations with promising results. Here, the WAgGCN composite showed significant photocatalytic performance to decolorized Methylene Blue (98%) and Crystal Violet (95%), together with high chemical stability and excellent recyclability. The presence of Ag shows the influences of surface plasmon resonance and acts as an electron mediator in the formed heterostructures. The photogenerated holes performed vital roles in the catalytic degradation of dye solutions over the WAgGCN composite catalyst, confirmed by radical trapping experiments. Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) measurements confirmed the mineralization of the dyes.

A rapid removal of Phaeocystis globosa from seawater by peroxymonosulfate enhanced cellulose nanocrystals coagulation

Cellulose nanocrystals (CNC) are recognized as promising bio-based flocculants for controlling harmful algal blooms (HABs). Due to the charge shielding effect in seawater and the strong mobility of algae cells, CNC can’t effectively remove Phaeocystis globosa from seawater. To solve this problem, peroxymonosulfate (PMS) was used to enhance the coagulation of CNC for rapidly removal of P. globosa. The results showed that 91.7% of Chl-a, 95.2% of OD680, and 97.2% of turbidity of P. globosa were reduced within 3 h with the use of 200 mg L−1 of CNC and 20 mg L−1 of PMS. The removal of P. globosa was consisted of inactivation and flocculation. Notably, electron paramagnetic resonance (EPR) spectrums and quenching experiments revealed that the inactivation of P. globosa was dominated by PMS oxidation and 1O2. Subsequently, CNC entrained inactivated algal cells to settle to the bottom to achieve efficient removal of P. globosa. The content of total organic carbon (TOC) and chemical oxygen demand (COD) decreased significantly, indicating that a low emission risk of algal cell effluent was produced in the CNC-PMS system. In view of the excellent performance on P. globosa removal, we believe that the CNC-PMS system has great potential for HABs treatments.

Microalgae-mediated tandem culture of shrimp and bivalve: an environmental and health co-benefits solution for phosphorus recovery and emission reduction

Phosphorus (P) accumulation in aquaculture systems is damaging our environment beyond acceptable levels. Devising strategies to potentially recover P from aquaculture systems in a reusable bioresource form is paramount and aligns with circular economy policies. In this study, we constructed two culture models, monoculture (Mon) and tandem culture (Tan), using Exopalaemon carinicauda and Mercenaria mercenaria. By monitoring the performance of rearing organisms, P dynamic patterns, and pollutant emissions, we found that: i) Compared to the Mon system, the Tan system demonstrated no differences in the performance of E. carinicauda and M. mercenaria, suggesting that the Tan model was viable in terms of fishery yield; ii) P in the Tan system could be efficiently recovered and removed from water and sediment, as indicated by the lower phosphate concentration in water (0.01 mg L−1), and the decrease in labile P in surface sediment (from 0.04 to 0.02 mg L−1). A combination of assimilatory and dissimilatory processes, mediated by phototrophic (bait-microalgae) and heterotrophic organisms (bivalves), appeared to be the primary mechanism for P utilization and removal; iii) The Tan system reduced pollutant emissions four times lower than the Mon system due to its minimal tailwater discharge (10%, 230 L). The emissions of total P, phosphate, total organic carbon, ammonium, and chemical oxygen demand from the Tan systems were 19 mg m−2 d−1, 2 mg m−2 d−1, 2 g m−2 d−1, 38 mg m−2 d−1, and 11 g m−2 d−1, respectively, 1.3, 1.7, 1.4, 1.3, and 1.2 times lower than those from the Mon systems. The eco-friendly Tan culture model fully exploited the resources of pond culture, a solution with environmental and health co-benefits for P recovery and emission reduction.

Responses of the structure and function of microbes in Yellow River Estuary sediments to different levels of mercury

The health and stability of the estuary of the Yellow River ecosystem have come under increasing pressure from land-based inputs of heavy metals. While it is known that heavy metals affect the function and health of the microbial community, there remains little knowledge on the responses of the microbial community to heavy metals, particularly highly toxic mercury. The research aimed to characterize the responses of the sediment microbial community of the estuary of the Yellow River to different levels of mercury stress. Estuary sediment samples were collected for microbial community analysis, measurement of mercury [including total mercury (THg) and methylmercury (MeHg)], and measurement of other physicochemical factors, including pH, total organic carbon (TOC), sulfide, iron ratio (Fe3+/Fe2+), ammonium salt (NH4+), and biochemical oxygen demand (BOD). The application of 16S rRNA sequencing identified 60 phyla of bacteria, dominated by Proteobacteria, Firmicutes, and Bacteroidetes. Stations with higher THg or MeHg and lower microbial abundance and diversity were generally distributed further outside of the estuary. Besides mercury, the measured physicochemical factors had impacts on microbial diversities and distribution. Metagenomics assessment of three stations, representative of low, moderate, and high mercury concentrations and measured physicochemical factors, revealed the abundances and functions of predicted genes. The most abundant genes regulating the metabolic pathways were categorized as metabolic, environmental information processing, and genetic information processing, genes. At stations with high levels of mercury, the dominant genes were related to energy metabolism, signal transport, and membrane transport. Functional genes with a mercury-resistance function were generally in the mer system (merA, merC, merT, merR), alkylmercury lyase, and metal-transporting ATPase. These results offer insight into the microbial community structure of the sediments in the Yellow River Estuary and the microbial function of mercury resistance under mercury stress.

Thermal power plants pollution assessment based on deep neural networks, remote sensing, and GIS: A real case study in Iran

To investigate the impact of the Bandar Abbas thermal power plant on the waters of the Persian Gulf coast, a combination of satellite images and ground data was utilized to determine the Sea Surface Temperature (SST) as a thermal index, Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) as biological indices. Additionally, measurements of SO2, O3, NO2, CO2, CO, and CH4 values in the atmosphere were taken to determine the plant's impact on air pollution. Temperature values of the water for different months were predicted using Long Short-Term Memory (LSTM), Support Vector Regression (SVR), and Cascade neural networks. The results indicate that the waters near thermal power plants exhibit the highest temperatures in July and September, with temperatures reaching approximately 50 °C. Furthermore, the SST values were found to be strongly correlated with ecological indices. The Multiple Linear Regression (MLR) analysis revealed a strong correlation between the temperature and TOC, COD, and O2 in water (RTOC2=0.98), RO22=−0.89, RCOD2=0.87 and O3, NO3, CO2, and CO in the air (RO32=0.99,RNO32=0.97,RCO22=0.95,RCO2=0.96). Finally, the results demonstrate that the LSTM method exhibited high accuracy in predicting the water temperature (R2 = 0.98).

Efficient Photocatalytic Degradation of Methylene Blue Dye from Aqueous Solution with Cerium Oxide Nanoparticles and Graphene Oxide-Doped Polyacrylamide.

A cerium oxide nanoparticles (CeO2-NPs)/graphene oxide (GO)/polyacrylamide (PAM) ternary composite was synthesized through free-radical polymerization of acrylamide in the presence of CeO2 nanoparticles and GO in an aqueous system. The synthesized composite material was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy techniques and applied for the photocatalytic degradation of methylene blue (MB) dye from an aqueous solution. Tauc's model for direct transition was used to model for the optical band gap. The key operating parameters such as the amounts of CeO2-NPs and GO, pH, initial MB concentration, type of light irradiation, and contact time have been optimized to achieve the highest MB degradation percentage. The photocatalysis process was pH-dependent, and the optimum pH value was found to be 12.0. Under UV-A light, 90% dye degradation occurred in 90 min. The degradation of MB was also specified in terms of total organic carbon (TOC) and chemical oxygen demand (COD). Free-radical capture experiments were also performed to determine the role of radical species during the photocatalytic oxidation process. The photocatalytic process showed that the equilibrium data is in good agreement with the Langmuir-Hinshelwood kinetic model. A rate constant of 0.0259 min-1 was obtained. The hydrogel was also tested to assess its reusability, which is an important key factor in practical wastewater treatment. The photocatalytic activity only decreased to 75% after nine uses.

Comparison of photocatalysis and photolysis of 2,2,4,4-tetrabromodiphenyl ether (BDE-47): Operational parameters, kinetic studies, and data validation using three modern machine learning models

Polybrominated diphenyl ethers (PBDEs) are halogenated organic compounds that are among the major pollutants of water, and there is an urgent need for their removal. This work compared the application of two techniques, i.e., photocatalytic reaction (PCR) and photolysis (PL), for 2,2,4,4- tetrabromodiphenyl ether (BDE-47) degradation. Although a limited degradation of BDE-47 was observed by photolysis (LED/N2), photocatalytic oxidation by using TiO2/LED/N2 proved to be effective in the degradation of BDE-47. The use of a photocatalyst enhanced the extent of BDE-47 degradation by around 10% at optimum conditions in anaerobic systems. Experimental results were systematically validated through modeling with three new and powerful Machine Learning (ML) approaches, including Gradient Boosted Decision Tree (GBDT), Artificial Neural Network (ANN), and Symbolic Regression (SBR). Four statistical criteria (Coefficient of Determination (R2), Root Mean Square Error (RMSE), Average Relative Error (ARER), and Absolute Error (ABER)) were calculated for model validation. Among the applied models, the developed GBDT was the desirable model for predicting the remaining concentration (Ce) of BDE-47 for both processes. Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) results confirmed that BDE-47 mineralization required additional time than its degradation in both PCR and PL systems. The kinetic study demonstrated that BDE-47 degradation for both processes followed the pseudo-first-order form of the Langmuir-Hinshelwood (L-H) model. More importantly, the calculated electrical energy consumption of photolysis was shown to be ten percent higher than that for photocatalysis, possibly due to the higher irradiation time required in direct photolysis, which in turn increases electricity consumption. This study is useful in proposing a feasible and promising treatment process for the degradation of BDE-47.

Photocatalytic treatment of real liquid effluent from hydrothermal carbonization of agricultural waste using metal doped TiO2/UV system

This study investigated treatment of real liquid effluent generated from hydrothermal carbonization (HTC) of macadamia nut shell by employing transition metals Cu, Ni, and Fe doped titanium dioxide (TiO2) photocatalysts. The anatase TiO2 based photocatalysts were prepared via sol-gel method, and calcined at 400 °C. The modification with metal dopants was performed via ultrasonic assisted incipient wetness impregnation method. The prepared photocatalysts were characterized using XRD, UV-Vis DRS, SEM-EDX, and N2 physisorption. The influence of metal dopants, types of TiO2 support, and initial pH of the wastewater on the photocatalytic degradation performance of total organic carbon (TOC) and chemical oxygen demand (COD) in the wastewater were investigated. The results revealed that Fe doped TiO2 exhibited the highest photocatalytic activity followed by Cu and Ni, respectively. Among all, Fe doped anatase TiO2 were the most promising catalyst as it performed the highest removal of 75.1% for TOC and 94.1% for COD after 1 h irradiation at pH 4, achieving the lowest TOC and COD concentration of 405.62 mg/L and 91.26 mg/L, respectively. The findings suggested that photocatalytic degradation of HTC liquid effluent could be a potential treatment before releasing the wastewater to the environment.