Degradation Kinetic Model Research Articles

Comparative Analysis and Kinetic Modeling of Marbofloxacin Degradation via Electro-Fenton and Biodegradation Optimization

In the quest for sustainable water purification methods, electrochemical Advanced Oxidation Processes (AOPs) emerge as pivotal strategies against organic pollutants. This study delves into the efficacy of the Electro-Fenton process, a distinguished AOP that leverages the in-situ generation of hydroxyl radicals (•OH) via the electrochemical reduction of oxygen. By conducting systematic experiments in deionized water, we evaluate the influence of catalyst concentration, applied current density, and cathode material selection on the degradation kinetics of marbofloxacin – a model pharmaceutical pollutant. Employing advanced statistical and kinetic modeling, our investigation reveals critical insights into the process dynamics, uncovering the nuanced interplay between operational parameters and degradation efficiency. The findings substantiate the Electro-Fenton process as an environmentally advantageous and effective solution for water decontamination and advancing the field of water purification technology.

Kinetic modeling of sulfonamide degradation by UV/H2O2: Deduction of ROH,UV modeling and application

Eight sulfonamide (SA) antibiotics were effectively degraded using a UV/H2O2 process in a quasi-collimated beam apparatus, utilizing optimized fluence quantification. Fluence-based rate constants (kk'SA) for the UV/H2O2 process were established. A curve-fitting method, derived from ROH,UV modeling, was developed for the UV/H2O2 process to quantitatively assess the impact of critical factors, including water quality and direct UV photolysis. It was observed that k'SA values approached a limiting value as initial H2O2 concentration increased. The specific second-order rate constants for •OH reactions with neutral and anionic SA species were determined to be within (2.2–5.7) × 10⁹ M⁻1 s⁻1, showing minimal variation among species. For the eight SAs studied, k'SA values were calculated from 3.9 × 10⁻⁴ to 6.0 × 10⁻2 cm2 mJ⁻1 across a typical pH range of 6.5–9.5. Direct UV photolysis was notably significant in SA degradation, particularly for sulfisoxazole, contributing at least 35%. An energy cost equation was formulated to evaluate the cost-effectiveness of SA degradation by UV/H2O2 and optimize operational parameters. This model, validated in real water scenarios, shows promise for predicting SA removal in UV/H2O2 processes. The developed curve-fitting method, pH-independent and accounting for both direct photolysis and OH radical reactions, is apt for modeling mixed-contaminant degradation in UV/H2O2 processes, simplifying calculations in ROH,UV modeling.

Occurrences of per- and Polyfluoroalkyl Substances (PFAS) in the Environment and Their Oxidative Degradation By Modified Fenton Treatment

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals that have become ubiquitous environmental contaminants due to their widespread use and extreme persistence. This research examines the remediation of PFAS, with a focus on oxidative degradation methods. PFAS are characterized by strong carbon-fluorine bonds that make them highly stable and resistant to degradation. They bioaccumulate in living organisms and have been linked to various adverse health effects, including liver damage, thyroid disruption, and developmental issues. Remediation approaches include adsorption, filtration, and advanced oxidation processes (AOPs). Fenton-based AOPs for PFAS degradation, particularly anodic Fenton treatment (AFT) and photo-assisted AFT (P-AAFT). AFT uses electrochemistry to generate hydroxyl radicals and regenerate ferrous ions, addressing limitations of classic Fenton treatment. P-AAFT incorporates UV irradiation to enhance radical production and PFAS degradation efficiency. Kinetic modeling of PFAS degradation is also evaluated, highlighting the importance of understanding reaction mechanisms and rates. The research seeks to advance understanding of PFAS degradation kinetics and mechanisms, potentially informing more effective remediation strategies for these persistent environmental contaminants. Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals that have become ubiquitous environmental contaminants due to their widespread use and extreme persistence. This literature review examines the occurrence, health impacts, regulation, and remediation of PFAS, with a focus on oxidative degradation methods. PFAS are characterized by strong carbon-fluorine bonds that make them highly stable and resistant to degradation. They bioaccumulate in living organisms and have been linked to various adverse health effects, including liver damage, thyroid disruption, and developmental issues. Remediation approaches include adsorption, filtration, and advanced oxidation processes (AOPs). Fenton-based AOPs for PFAS degradation, particularly anodic Fenton treatment (AFT) and photo-assisted AFT (P-AAFT). AFT uses electrochemistry to generate hydroxyl radicals and regenerate ferrous ions, addressing limitations of classic Fenton treatment. P-AAFT incorporates UV irradiation to enhance radical production and PFAS degradation efficiency. Kinetic modeling of PFAS degradation is also discussed, highlighting the importance of understanding reaction mechanisms and rates. The research seeks to advance understanding of PFAS degradation kinetics and mechanisms, potentially informing more effective remediation strategies for these persistent environmental contaminants.

Microblog‐Assisted Synthesis of Schiff Base Network Polymers for SO2/Epoxide Copolymerization and Thermal Degradation Kinetics of the Products

AbstractThis study successfully prepared three environmentally friendly Schiff base network (SNW) polymers, SNW‐1, SNW‐2, and SNW‐3, using melamine and aldehyde compounds as raw materials through a microwave‐assisted synthesis method. The SNW materials were applied to catalyze the copolymerization reaction of SO2 and epoxides. Through detailed analysis of the chemical structure and properties of SNW‐1, SNW‐2, and SNW‐3, their catalytic efficiency was thoroughly investigated. Three thermal degradation kinetic models, Flynn–Wall–Ozawa (FWO), Kissinger, and Coats–Redfern, were employed to calculate the kinetic parameters of the thermal degradation of poly(cyclohexene sulfite) (PCS). Potential thermal degradation mechanisms were speculated. Additionally, the Kissinger model accurately described the thermal degradation kinetics features of PCS. Based on experimental results and kinetic analysis, this paper elucidates the potential mechanism of the copolymerization reaction of SO2 and epoxides. The study indicates that microwave‐assisted synthesis exhibits convenience and high efficiency in preparing efficient catalysts, demonstrating significant potential across various application domains.

Degradation of handmade paper: Exploration of water adsorption behavior and estimation of lifespan based on time-temperature-humidity superposition

Traditional handmade papers, as the carriers of paper-based cultural relics, inevitably undergo various deteriorations during long-term preservation. Establishing a reasonable degradation kinetic model of handmade paper under the synergistic action of multiple factors is the crucial to evaluate paper aging and lifespan of paper. This study explores the moisture content and diffusion behavior of water molecules in traditional handmade paper to identify the interaction between fibers and water molecules at the accessible sites by two-dimensional infrared spectroscopy (2D-COS). Additionally, the optimized second-order kinetic models for the degradation of three types of Kaihua handmade papers was presented based on the time-temperature-humidity superposition method. A time-temperature-humidity translation factor is incorporated into the dynamic model to quantitatively analyze the synergistic effect of temperature and humidity on the degradation rate of handmade paper. The degradation rates of handmade paper with different raw materials and handcraft processes demonstrated significant effects of the cooking and bleaching processes on the aging degradation process and the durability of the paper. The improved second-order degradation kinetic model, considering the cooperation process with multi-factors and mechanisms, enables the extrapolation of paper aging properties at arbitrary temperature and humidity effectively, which provides a more reasonable estimation of handmade paper's lifespan.

Degradation Behavior of Medical MgZZC-1 in Various Simulated Body Fluids.

Magnesium-based biodegradable metal bone implants exhibit superior mechanical properties compared to biodegradable polymers for orthopedic and cardiovascular stents. In this study, MgZZC-x (x = 1, 1.2) alloys were screened by in vitro biocompatibility tests in three simulated body fluids under nontoxic conditions. The MgZZC-1 alloys with better biocompatibility were selected to predict the days required for complete degradation. The evolution of degradation products was analyzed, and the mechanism of formation of the product film was inferred. A degradation kinetic model was established to investigate the effect of MEM components on the degradation of the alloys. The results demonstrate that the proteins in MEM can greatly retard the degradation progress by attaching to the surface of MgZZC-1 alloys, which are predicted to degrade completely within 341 days. The carbonate and phosphate buffers were adjusted to pH in MEM solution, delaying the degradation of magnesium alloys. This process in MEM more accurately reflects the actual degradation in the body and is superior to that in Hanks and SBF solutions. This study will promote the application of biodegradable materials in clinical medicine.

Efficient degradation and enhanced anticomplementary activity of Belamcanda chinensis (L.) DC. polysaccharides via trifluoroacetic acid treatment with different degrees

The degradation of Belamcanda chinensis (L.) DC. polysaccharides was carried out by five concentrations of trifluoroacetic acid (TFA) (1–5 mol/L), and their physicochemical properties, degradation kinetics and anticomplementary activity were investigated. The findings revealed a notable reduction in the molecular weight of BCP, from an initial value of 2.622 × 105 g/mol to a final value of 6.255 × 104 g/mol, and the water solubility index increased from 90.66 ± 0.42 % to 97.78 ± 0.43 %. The degraded polysaccharides of B. chinensis exhibited a comparable monosaccharide composition comprising Man, GalA, Glc, Gal, and Ara. As the concentration of TFA increased, the degradation rate constant increased from 1.468 × 10−3 to 5.943 × 10−3, and the process followed the first-order degradation kinetic model (R2 > 0.97) and the random fracture model (R2 > 0.96). Furthermore, the five degraded polysaccharides still exhibit good thermal stability. In vitro experiments showed that DBCP-3 exhibited more potent anticomplementary activity than the original polysaccharides and positive drugs, which was strongly correlated with its Mw (r = 0.6–0.8), inhibiting complement activation by blocking C2 and C4. These results indicated that TFA degradation has a positive effect on polysaccharides, of which DBCP-3 is expected to treat diseases involving hyperactivation of the complement system.

Assessment of hydrocarbon degradation capacity and kinetic modeling of Chlorella vulgaris and Scenedesmus quadricauda for crude oil phycoremediation under mixotrophic conditions

Crude oil spills imperil aquatic ecosystems globally, prompting innovative solutions such as microalgae-based bioremediation. This study explores the potential of Chlorella vulgaris and Scenedesmus quadricauda, for crude oil spill phycoremediation under mixotrophic conditions and varying crude oil concentrations (0.5–2%). C. vulgaris demonstrated notable resilience, thriving up to 1% crude oil exposure, while S. quadricauda adapted to lower concentrations. Optimal growth for both was observed at 0.5% exposure. Chlorophyll a content in C. vulgaris increases at 0.5% exposure but declines above 1%, while a decline was noticeable in chlorophyll b in treatment groups above 1%. Carotenoid levels varied, displaying the highest levels at higher concentrations above 1.5%. Similarly, S. quadricauda showed increased chlorophyll a content at 0.5% exposure, with stable carotenoid levels and a decline in chlorophyll b content at higher concentrations. GC/MS analyses indicated C. vulgaris efficiently degraded aliphatic compounds like decane and tridecane, surpassing S. quadricauda in degrading both aliphatic and aromatic hydrocarbons. Growth kinetics was best represented by the modified Gompertz and logistic models. These findings highlight the species-specific adaptability and optimal concentration for microalgae to degrade crude oil effectively, advancing phycoremediation processes and strategies critical for environmental restoration.

Integrated whole genome sequencing and transcriptomic analysis reveal the biodegradation mechanism of vanillic acid in Herbaspirillum aquaticum KLS-1

Vanillic acid (VA) is a phenolic compound frequently present in wastewater and agricultural soil. High concentrations of VA will increase the burden of sewage treatment and pose toxicity to crop plants. Although advanced oxidation has been successfully used to remove VA, green and sustainable treatments for VA pollution with efficient VA-degrading microbes, especially about the full pathways of VA degradation, are not well documented. In this study, a full investigation of VA degradation ability and associated metabolic mechanisms in the new VA-degrading bacterium Herbaspirillum aquaticum KLS-1 was performed. Results showed that strain KLS-1 completely removed 500 mg/L VA within 36 h following a zero-order degradation kinetic model with a degradation half-time of 15.01 h. An efficient VA degradation occurred under the conditions with pH values of 7–9, temperatures of 30–40 °C, and shaking speeds of 150–200 rpm. A fed-batch experiment and SEM analysis showed that strain KLS-1 exhibited a good ability to remove up to 46.8 mg VA without cellular damage. The protocatechuate ortho-cleavage pathway was probably associated with efficient VA degradation in strain KLS-1 according to the whole genome sequencing and transcriptomic analysis. This study has offered a comprehensive understanding of full VA degradation mechanisms in microbes by using genomic sequencing coupled with transcriptomic analysis and provided a new VA-degrading bacterium for potential bioremediation of VA pollution.

Exploring predictive kinetic modelling of thermal degradation from laboratory to production scale – A case study on three vitamins in milk

Kinetic thermal degradation models are vital components for optimization of food and bioproducts processing. Typically, models are fitted to laboratory-scale experiments where vials are heated and held. However, these conditions are highly dissimilar from the thermal processes experienced in industrial production. Whereas fitting kinetic data to industrial-scale production is often impossible due to cost and flexibility issues, this discrepancy between what is typically measured and what the models are intended for could be of concern. This study presents a case study where traditional laboratory experiments are fitted to vitamin degradation kinetic models in milk (vitamins B1, B2, and E). The best-fitted kinetic models are then validated using five, carefully controlled industrial-scale dairy processes. Results show that predictions are surprisingly close to the validation data (mean relative percentual deviation is −1.1 %–+3 % depending on vitamin), given the substantial difference between the laboratory and production scale setup. This offers empirical support for the conventional method of fitting kinetic parameters through simplified laboratory experiments to predict vitamin degradation during industrial scale processing of foods and bioproducts.

Cobalt-catalysed bicarbonate-activated peroxide as a promising system for the advanced oxidation of epirubicin in wastewaters

Epirubicin (EPI) is a common cytostatic drug often found as a pollutant in hospital wastewater. While many studies have focused on the degradation kinetics of its epimer, doxorubicin (DOX), none have reported the kinetics of EPI degradation. Herein, we report a new cost-efficient, environmentally friendly system for the advanced degradation of EPI consisting of cobalt-catalysed bicarbonate-activated peroxide. We propose a new kinetic model for EPI degradation that shows the hydroperoxyl radical is the most important reactive oxygen species (ROS) involved in the degradation process. Seven degradation products are identified using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS). The effect of surfactants, commonly found in wastewaters, is also investigated and the presence of the cationic surfactant hexadecylpyridinium chloride (CPC) in the reaction medium leads to a 6.1-fold increase in the degradation rate. Modelling the reaction kinetics using the Piszkiewicz model unveils the rate constant for the micellar degradation of EPI to be 4.66×10‐3s‐1. The ecotoxicity study of the degradation products shows a dramatic decrease in both acute and chronic toxicity. Although the level of mineralisation of the products is less than 10%, this method is still suitable as a pre-treatment of wastewaters. The same system is successfully used for the degradation of DOX, mitoxantrone, and quinizarin. In the case of DOX, a rate constant of 3.74×10‐2s‐1 is obtained, the highest reported so far.

Novel kinetic modeling of photocatalytic degradation of ethanol and acetaldehyde in air by commercial and reduced ZnO: Effect of oxygen vacancies and humidity

A comprehensive kinetic model has been developed to address the factors and processes governing the photocatalytic removal of gaseous ethanol by using ZnO loaded in a prototype air purifier. This model simultaneously tracks the concentrations of ethanol and acetaldehyde (as its primary oxidation product) in both gas phase and on the catalyst surface. It accounts for reversible adsorption of both compounds to assign kinetic reaction parameters for different degradation pathways. The effects of oxygen vacancies on the catalyst have been validated through the comparative assessment on the catalytic performance of commercial ZnO before and after the reduction pre-treatment (10% H2/Ar gas at 500 °C). The influence of humidity has also been assessed by partitioning the concentrations of water molecules across the gas phase and catalyst surface interface. Given the significant impact of adsorption on photocatalytic processes, the beginning phases of all experiments (15 min in the dark) are integrated into the model. Results showcase a notable decrease in the adsorption removal of ethanol and acetaldehyde with an increase in relative humidity from 5% to 75%. The estimated number of active sites, as determined by the model, increases from 7.34 10−6 in commercial ZnO to 8.86 10−6 mol gcat−1 in reduced ZnO. Furthermore, the model predicts that the reaction occurs predominantly on the catalyst surface while only 14% in the gas phase. By using quantum yield calculations, the optimal humidity level for photocatalytic degradation is identified as 25% with the highest quantum yield of 6.98 10−3 (commercial ZnO) and 10.41 10−3 molecules photon−1 (reduced ZnO) catalysts.

Kinetic Assessment of Kraft and Thermally Upgraded Kraft Papers Aged in Five Alternative Dielectric Fluids.

The lifespan of an electrical transformer, primarily determined by the condition of its solid insulation, is well known under various operating conditions when mineral oil is the coolant in these machines. However, there is a trend toward replacing this oil with biodegradable fluids, especially esters; therefore, an understanding of the ageing of solid insulation with these fluids is essential. Currently available data do not allow for the selection of the best ester among those available on the market, as each study applies different conditions, making it impossible to compare results. Thus, this paper analyses the degradation of Kraft and Thermally Upgraded Kraft papers with the following five most promising commercial esters: sunflower, rapeseed, soybean, palm, and synthetic. The materials underwent accelerated thermal ageing at 130, 150, and 170 °C, and the integrity of the papers was evaluated through their polymerisation degree and the obtaining of the degradation kinetic models. The wide range of materials studied in this work, which were subjected to the same treatments, allows for a comparison of the esters, revealing significant differences in the impact of the alternative fluids. Sunflower, rapeseed, and soybean esters provided the best paper protection, i.e., the degree of polymerisation of Kraft paper in the tests at 150 °C decreased by 71% with these fluids, compared to the 83% reduction with mineral oil, 79% reduction with palm ester, and 75% reduction with synthetic ester. Furthermore, different kinetic models were obtained to predict the degradation; it was concluded that the Emsley model provides the best fit. Additionally, it was found that the behaviour of a dielectric fluid with one type of paper cannot be extrapolated, which is only noticeable in broad-scope studies.

Modeling the performance of multilayer insulation in cryogenic tanks undergoing external fire scenarios

Multilayer Insulation (MLI) is frequently used in vacuum conditions for the thermal insulation of cryogenic storage tanks. The severe consequences of the degradation of such materials in engulfing fire scenarios were recently evidenced by several large-scale experimental tests. In the present study, an innovative modelling approach was developed to assess the performance of heat transfer in polyester-based MLI materials for cryogenic applications under fire conditions. A specific layer-by-layer approach was integrated with an apparent kinetic thermal degradation model based on thermogravimetric analysis results. The modeling results provided a realistic simulation of the experimental data obtained by High-Temperature Thermal Vacuum Chamber tests reproducing fire exposure conditions. The model was then applied to assess the behavior of MLI systems for liquid hydrogen tanks in realistic fire scenarios. The results show that in intense fire scenarios degradation occurs rapidly, compromising the thermal insulation performances of the system within a few minutes.

Unlocking the power of activated carbon-mediated peracetic acid activation for efficient antibiotics abatement in groundwater: Coupling the processes of electron transfer, radical production, and adsorption

The activation of peracetic acid (PAA) by activated carbon (AC) is a promising approach for reducing micropollutants in groundwater. However, to harness the PAA/AC system’s potential and achieve sustainable and low-impact groundwater remediation, it is crucial to quantify the individual contributions of active species. In this study, we developed a combined degradation kinetic and adsorption mass transfer model to elucidate the roles of free radicals, electron transfer processes (ETP), and adsorption on the degradation of antibiotics by PAA in groundwater. Our findings reveal that ETP predominantly facilitated the activation of PAA by modified activated carbon (AC600), contributing to ∼61% of the overall degradation of sulfamethoxazole (SMX). The carbonyl group (CO) on the surface of AC600 was identified as a probable site for the ETP. Free radicals contributed to ∼39% of the degradation, while adsorption was negligible. Thermodynamic and activation energy analyses indicate that the degradation of SMX within the PAA/AC600 system requires a relatively low energy input (27.66 kJ/mol), which is within the lower range of various heterogeneous Fenton-like reactions, thus making it easily achievable. These novel insights enhance our understanding of the AC600-mediated PAA activation mechanism and lay the groundwork for developing efficient and sustainable technologies for mitigating groundwater pollution. Environmental ImplicationThe antibiotics in groundwater raises alarming environmental concerns. As groundwater serves as a primary source of drinking water for nearly half the global population, the development of eco-friendly technologies for antibiotic-contaminated groundwater remediation becomes imperative. The innovative PAA/AC600 system demonstrates significant efficacy in degrading micropollutants, particularly sulfonamide antibiotics. By integrating degradation kinetics and adsorption mass transfer models, this study sheds light on the intricate mechanisms involved, emphasizing the potential of carbon materials as sustainable tools in the ongoing battle for clean and safe groundwater.

Mathematical Modeling of Alpha-Tocopherol Early Degradation Kinetics to Predict the Shelf-Life of Bulk Oils.

The kinetics of lipid oxidation includes a lag phase followed by an exponential increase in oxidation products, which cause rancidity. Current models focus on the slope of this exponential curve for shelf-life estimation, which still requires the measurement of full oxidation kinetics. In this paper, we analyzed the formation of lipid oxidation products in stripped soybean oil containing different levels of α-tocopherol. The lag phases of lipid hydroperoxides and headspace hexanal formation were found to have a strong positive correlation with the α-tocopherol depletion time. We propose that the kinetics of antioxidant (α-tocopherol) depletion occur during the lag phase and could serve as an early shelf-life indicator. Our results showed that α-tocopherol degradation can be described by Weibull kinetics over a wide range of initial concentrations. Furthermore, we conducted in silico investigations using Monte Carlo simulations to critically evaluate the feasibility and sensitivity of the shelf-life prediction using early antioxidant degradation kinetics. Our results revealed that the shelf life of soybean oil may be accurately predicted as early as 20% of the overall shelf life. This innovative approach provides a more efficient and faster assessment of shelf life, ultimately reducing waste and enhancing product quality.

Photocatalytic degradation of rhodamine B over Z-scheme photocatalyst BiFeO3/3DOM-TiO2-x in a fixed-bed reactor

In this work, a Z-scheme BiFeO3/3DOM-TiO2-x photocatalyst was synthesized using a hydrothermal method and extensively evaluated for its photocatalytic capabilities in the rhodamine B (RhB) degradation within a fixed-bed reactor. The results demonstrated the synergistic effects of enhanced visible light absorption, a Z-scheme charge transfer mechanism, oxygen vacancies, and unique three-dimensional ordered macropore structure, which collectively enhance the photocatalytic activity of BiFeO3/3DOM-TiO2-x. The active groups responsible for RhB degradation included hydroxyl radicals (•OH), hole (h+), and reactive superoxide radical (•O2−), of which •O2− played a predominant role in RhB photodegradation. A kinetic model of dye degradation in a fixed-bed reactor was proposed, providing a realistic description of RhB degradation.

Natural degradation of polypyrrole nanowires in NaOH solutions and its degradation kinetics

The polypyrrole (PPy) nanowires doped with p-toluenesulfonate ions (PPy/pTS NWs) are prepared and degraded in aerated and deaerated NaOH solutions (CNaOH=0.02 - 0.5 M) for different times to examine their natural degradation behavior and kinetics. After degradation, the fluffy PPy/pTS NWs network film generally exhibits a uniform natural degradation state with apparent damaged areas on the nanowires' surface, decreased nanowire diameter, and increased film thickness. The electroactivity degradation of PPy/pTS NWs still follows the first-order degradation kinetics, like the bulk-structured PPy/pTS films. The natural degradation kinetics model established from the bulk-structured PPy films is proven to apply to PPy/pTS NWs. The rate equations for the chemical and electrochemical degradation of PPy/pTS NWs in NaOH solutions are determined. Additionally, it is confirmed that the electrochemical degradation process is the dominant factor, while CNaOH significantly impacts the chemical degradation process. The structural features of PPy/pTS NWs do not alter the chemical and electrochemical degradation processes but significantly accelerate the degradation rates. This research will contribute to our understanding of the degradation kinetics of PPy nanomaterials and support their practical applications.

Acetylene black doped zinc oxide (AB-ZnO) nanorods activated peroxydisulfate for degradation of dyeing wastewater

Zinc oxide (ZnO) nanorods and acetylene black (AB) doped ZnO (AB-ZnO) nanorods were fabricated by the hydrothermal method, and characterized by various methods (XRD, EDS, SEM, BET, FT-IR, Zeta potential). The photo-catalytic degradation ability of AB-ZnO/PDS/vis system on simulated dyeing wastewater was studied with methyl orange (MO) as the target pollutant. The effects of AB doping ratio, AB-ZnO dosage, PDS concentration, initial pH, and temperature on MO degradation were comprehensively investigated. The AB-ZnO/PDS/vis system has a wide range of pH applications from 3 to 11. The prepared material of AB-ZnO had excellent stability that the degradation efficiency on MO remained above 90 % after 4 cycles. The theoretical optimal removal rate of MO was 98.59 % when AB-ZnO dosage was 1.0 g/L, PDS concentration was 2.0 mmol/L, initial pH was 5, and temperature was 50 °C. Furthermore, degradation kinetic model, the orthogonal experiment and the degradation mechanisms were elaborated. By using methanol and tert-butanol as free radical inhibitors, it was confirmed that SO4·- and ·OH were the main active free radicals in AB-ZnO/PDS/vis system.

Degradation kinetics of organic matter in domestic sewage by sequencing batch reactor

The sequencing batch reactor (SBR) has become a popular sewage treatment process in various industries due to its strong impact load resistance and numerous other advantages. This study examines the variations of chemical oxygen demand chromium (CODcr), ammoniacal nitrogen (NH3-N), total bound nitrogen (TN) and total phosphorus (TP) with aeration time to investigate the degradation patterns of different pollutants during the SBR’s reaction stage. Additionally, an organic matter degradation kinetic model was developed. The experimental results showed that the CODcr and NH3-N in the reactor met the national discharge standards after two hours of influent. Furthermore, the removal rates of CODcr and NH3-N exceeded 85% and 99%, respectively, at the end of the final aeration. At the same time, the TN and TP removal rates remained stable at approximately 45% and 68%. The analysis of the kinetic model showed that the degradation process of organic matter followed a first-order kinetic equation: S=S0e−0.00012Xt. The regression model's fitting value exhibited a high degree of conformity with CODcr removal’s experimental results, with the average relative error of 5.52% falling within an acceptable range. Furthermore, the correlation coefficient (0.9966) indicated high accuracy and effectively represented the changes in organic matter throughout the SBR reaction stage. Consequently, this model can serve as a theoretical foundation for determining CODcr’s maximum treatment capacity in experimental wastewater.