Atrazine Degradation Research Articles

Electrochemically activated calcium sulfite for atrazine degradation: Performance, mechanism and kinetics

The conventional use of Na2SO3 in advanced oxidation processes leads to excessive dissolved SO32−, limiting the utilization of oxysulfur species. This study introduced an electrochemically activated CaSO3 (EC-CaSO3) process that exploited the slow-release property of CaSO3. The results showed that the removal ratios of several micropollutants were over 90 % within 10 min, with SO4•− as the primary oxidant. A mathematic model was further developed to simulate the radical conversion, analyze the degradation kinetics and optimize the operational parameters, using atrazine (ATZ) as the target pollutant. The continuous low concentration of SO32− promoted O2 evolution for oxysulfur species transformation and reduced SO4•− quenching. This resulted in 74 % of SO3•− converting to SO5•− and 84 % of SO32− contributing to SO4•− formation. In the initial 2 min, the matched electro-generation of SO3•− and O2 remarkably accelerated SO4•− generation, leading to 82 % removal of ATZ. As electrolysis continued, the reduced release rate of SO32− prevented excessive accumulation of SO32− and maintained high O2 evolution rate to drive SO4•− generation. Consequently, complete degradation of ATZ was achieved within 5 min, with the contribution of SO4•− exceeding 99 %. By investigating the influence of operational parameters on ATZ degradation and energy consumption, the cost-effective conditions (EE/O values < 2.2 kWh/m3/order) occurred at pH above 7, current densities of 60 to 90 A/m2 and initial CaSO3 dosages of 2 to 4 mM. Additionally, density functional calculation and LC-MS analysis confirmed the formation of less toxic intermediates through dealkylation and dechlorination-hydroxylation. These findings suggested that EC-CaSO3 process was a promising technology for oxidizing micropollutants.

Stage dependent microbial dynamics in hepatocellular carcinoma and adjacent normal liver tissues

The interactive pathway of the gut-liver axis underscores the significance of microbiome modulation in the pathogenesis and progression of various liver diseases, including hepatocellular carcinoma (HCC). This study aims to investigate the disparities in the composition and functionality of the hepatic microbiota between tumor tissues and adjacent normal liver tissues, and their implications in the etiology of HCC. We conducted a comparative analysis of the hepatic microbiome between adjacent normal liver tissues and tumor tissues from HCC patients. Samples were categorized according to the modified Union for International Cancer Control (mUICC) staging system into Non-tumor, mUICC stage I, mUICC stage II, and mUICC stage III groups. Microbial richness and community composition were analyzed, and phylogenetic profiles were examined to identify significantly altered microbial taxa among the groups. Predicted metabolic pathways were analyzed using PICRUSt2. Our analysis did not reveal significant differences in microbial richness and community composition with the development of HCC. However, phylogenetic profiling identified significantly altered microbial taxa among the groups. Sphingobium, known for degrading polychlorinated biphenyls (PCBs), exhibited a significantly negative correlation with clinical indices in HCC patients. Conversely, Sphingomonas, a gut bacterium associated with various liver diseases, showed a positive correlation. Predicted metabolic pathways suggested a correlation between atrazine degradation and valine, leucine, and isoleucine biosynthesis with mUICC stage and tumor size. Our results underscore the critical link between hepatic microbial composition and function and the HCC tumor stage, suggesting a potentially pivotal role in the development of HCC. These findings highlight the importance of targeting the hepatic microbiome for therapeutic strategies in HCC.

Construction of BaTiO3/g-C3N4 heterojunction for promoting atrazine degradation of hydraulic-driven piezocatalytic ozonation

Catalytic ozonation, as a popular water purification technology, was restrained with the dilemma of slow Me(n+m)+/Men+ redox cycle of the convention catalysts. To this end, BaTiO3/g-C3N4 (BTO/CN) piezoelectric heterojunction was designed to enhance atrazine (ATZ) degradation in piezocatalytic ozonation, utilizing the overlooked mechanical forces to activate O3 into reactive oxygen species (ROS). Characterization results demonstrated that the couple of BTO and CN successfully formed a Type-II heterojunction, enhancing the separation of piezoelectric carriers (e- and h+). Moreover, BTO/CN showed the better O3 affinity and O3 activation capability over that of BTO and CN. BTO/CN/O3 process achieved 90.1 % ATZ removal, which was 3.5 and 1.7 times over that of the BTO/O3 and CN/O3 processes, respectively. ATZ removal in BTO/CN/O3 process increased with the initial pH value. Cl-, SO42- and NO3- inhibited ATZ removal, but HCO3- enhanced ATZ removal. O3, •OH, O2- and 1O2 were all involved in ATZ degradation and •OH served as the main ROS, accounting for 79.3 % in degrading ATZ. The internal electric field along with the interfacial electric field synergistically boosted the separation and transfer of charge carriers to provide e- for O3 activation and ROS generation. This study broke through the basic need of continuous sacrifice of e- for O3 activation induced by metal redox cycle and provided a novel catalyst design strategy for piezoelectric ozonation.

Degradation of Atrazine in Water by Dielectric Barrier Discharge Combined with Periodate Oxidation: Enhanced Performance, Degradation Pathways, and Toxicity Assessment.

The widespread occurrence of atrazine (ATZ) in water environments presents a considerable risk to human health and ecosystems. Herein, the performance of dielectric barrier discharge integrated with periodate (DBD/PI) for ATZ decomposition was evaluated. Results demonstrated that the DBD/PI system improved ATZ decomposition efficiency by 18.2-22.5% compared to the sole DBD system. After 10 min treatment, the decomposition efficiency attained 82.4% at a discharge power of 68 W, a PI dosage of 0.02 mM, and an initial ATZ concentration of 10 mg/L. As the PI dosage increased, the decomposition efficiency exhibited a trend of initially increasing, followed by a decrease. Acidic conditions were more favorable for ATZ removal compared to alkaline and neutral conditions. Electron paramagnetic resonance (EPR) was adopted for characterizing the active species produced in the DBD/PI system, and quenching experiments revealed their influence on ATZ decomposition following a sequence of 1O2 > O2-• > IO3• > OH•. The decomposition pathways were proposed based on the theoretical calculations and intermediate identification. Additionally, the toxic effects of ATZ and its intermediates were assessed. This study demonstrates that the DBD/PI treatment represents an effective strategy for the decomposition of ATZ in aquatic environments.

Coordination dependent photocatalytic peroxymonosulfate activation on biomass derived Fe single atom catalysts for atrazine degradation

Challenges associated with uncontrollable metal coordination structures in biomass-derived single-atom catalysts (SACs) and their intricate impacts on photocatalytic peroxymonosulfate (PMS) activation pose significant hurdles for the application of photo-Fenton technology towards wastewater treatment. Herein, we employed a co-pyrolysis strategy using Enteromorpha prolifera (E. prolifera) to synthesize Fe SACs with varying Fe–NX coordination, i.e., Fe–N5 and Fe–N6. Fe–N6-based SAC achieved over 80% atrazine (ATZ) degradation in 15 min, with a degradation rate of 0.13 min−1, representing 2.6-fold improvement over SAC with Fe–N5 structure. Experimental and simulation results revealed that Fe–N6 active sites acted as electron donors, enhancing the delocalization of π-electrons and improving photocatalytic PMS activation. This SAC also exhibited high selectivity for 1O2 degradation pathway and impressive ATZ degradation in seawater, with notable chlorine resistance, underscoring its potential in environmental pollutant remediation. This work unveils the catalyst structure-photocatalytic PMS activation performance relationship, offering avenue for developing more sustainable and efficient biomass-derived SACs for wastewater treatment.

Complexity of influences on atrazine phytoremediation of coexisting graphene oxide in water: Mitigating its phytotoxicity while decreasing plant removal contribution

Phytoremediation is an efficient technology for the removal of herbicide atrazine (ATZ) contamination in water bodies, but its ability to reduce ATZ under combined pollution remains unclear, especially ATZ co-existing with the emerging pollutant graphene oxide (GO) that may have potential effects on ATZ fate, plants and microbes. Herein, we investigated the phytoremediation potential of an emergent plant (Iris pseudacorus) for ATZ and the response of bacteria in a hydroponic system with and without GO. The results showed that plants enhanced ATZ dissipation in water with the increased removal rate by a factor of 1.7–4.0. GO restricted ATZ uptake by plants, but favored ATZ bioconcentration in cell walls. The plant contributed most to changes in the bacterial communities, decreasing the alpha diversity, while enriching the functional categories involving in amino acid and carbohydrate metabolisms. These findings indicated that I. pseudacorus can be employed as an effective candidate of phytoremediation for ATZ co-existing with GO at environmentally relevant concentrations, tending to recruit bacteria with plant stress tolerance and growth-promotion activities more than with ATZ degradation activities; GO exerted a mitigating effect on ATZ stress improving the barrier function of cell walls, but decreased the contribution of plants to ATZ removal.

Higher biodegradation rate of atrazine by Paenarthrobacter sp. KN0901 with P-doped hydrochar: The important role of biofilm regulated by autoinducer-2 regulated quorum sensing during the degradation process

The presence of atrazine residue in runoff from agricultural areas poses a significant risk to the ecosystem. This study aimed to develop microorganism-material systems using the atrazine-degrading strain Paenarthrobacter sp. KN0901 and P-doped hydrochar to effectively remove atrazine residues from aquatic environments. The atrazine degradation rate increased by 22.6 % with the addition of P-doped hydrochar after three days of incubation at 15 °C. Autoinducer-2 activity increased from 100 % to 116.7 % with P-doped hydrochar addition, indicating improved quorum sensing compared to free microorganisms. The extracellular polymeric substance content was significantly higher in the PHC groups compared to the blank groups, suggesting enhanced biofilm formation. Quorum sensing was inhibited by the use of nitazoxanide and sodium nitroprusside, leading to decreased atrazine degradation. In contrast, the presence of glucose and S-adenosyl methionine enhanced the rate of atrazine degradation due to elevated quorum sensing. These results suggested that P-doped hydrochar enhanced strain KN0901′s ability to assemble, increasing quorum sensing and accelerating atrazine degradation. Additionally, P-doped hydrochar promoted atrazine degradation by strain KN0901 under various conditions by enhancing quorum sensing. This work offers a new perspective on developing and using bioremediation techniques to remediate atrazine-contaminated environments under diverse conditions.

Explore synergistic catalytic ozonation by dual active sites of oxygen vacancies and defects in MgO/biochar for atrazine degradation

The design of highly efficient and sustainable catalytic materials is highly desirable for the development of advanced oxidation process (AOPs) used in water treatment. This study used waste litchi shells as precursors to prepare biochar (BC). The composite material (BC@MgO) was synthesized upon loading magnesium oxide (MgO) on BC and used for the heterogeneous catalytic ozonation (HCO) of atrazine (ATZ). BC@MgO exhibited an ATZ degradation rate of 92.8 % over 30 min under the optimal degradation conditions and maintained its good catalytic performance over four cycles, exhibiting excellent catalytic activity and stability. Characterization and experimental results revealed the synergistic effect of oxygen vacancies (OVs) and BC defects on the adsorption and decomposition of ozone molecules. The exposure of the surface magnesium ions was promoted in the presence of OVs on MgO, allowing water molecules to dissociate on the surface magnesium sites to form surface hydrated hydroxyl groups. Biochar defects accelerated the adsorption of ozone molecules by virtue of its higher surface energy. These active sites led to the substantial generation of reactive oxygen species (ROS), which possessed strong oxidizing ability and thereby participated in the degradation of ATZ. In addition, the possible degradation pathways and toxicity of ATZ were evaluated. Overall, this design provided a novel approach to the comprehensive utilization of waste lychee shells, as well as an efficient, stable, and green catalyst for the development of AOPs used in water treatment.

Peroxymonosulfate activation by CoO@C catalyst from integrated recycling of spent lithium-ion battery: Performance and mechanism

Developing low-cost, highly active transition metal-based catalysts for peroxymonosulfate (PMS) activation is essential but remains challenging. Herein, we proposed a novel “waste-to-energy” strategy to derive an effective PMS activator (CoO@C) by integrally utilizing the abundant Co content in the cathodes and the defective structure of anode graphite from spent lithium-ion batteries (LIBs). The CoO@C/PMS system could completely degrade atrazine (ATZ) within 15 min, along with a robust resilience to coexisting substrate and a wide pH range of 5.0–11.0. Through quenching experiments and electron paramagnetic resonance (EPR), •OH was identified as the primary reactive oxygen species (ROS) responsible for ATZ degradation. Furthermore, electron transfer between the catalyst and PMS was examined via density functional theory (DFT) calculations to elucidate the activation mechanism. The Fukui index pinpointed the vulnerable sites of ATZ, offering insights into the possible degradation pathways along with UHPLC-MS analysis. Furthermore, CoO@C was fixed on a polyethersulfone (PES) membrane for continuous degradation of ATZ, which maintained a degradation efficiency exceeding 90 % after treating 6 L of wastewater. This research provided valuable insights into the preparation of metal-based catalysts for advanced oxidation processes and achieved the sustainable utilization of spent LIBs.

Degradation and mineralization of atrazine by ozonation: A toxicological prediction by QSAR toolbox

This work aims to investigate the atrazine (ATZ) mitigation by an advanced oxidative process. Atrazine is one an effective herbicide which has been detected in water sources, causing contamination problems. To address the persistent issue of contamination, ATZ degradation and mineralization were studied by ozonation. In addition, the eco-toxicity of the possible degradation byproducts was also evaluated by the Quantitative Structure-Activity Relationship (QSAR) OECD toolbox. To evaluate the influence and predict the optimum conditions of the ozonation process and the reaction time on the degradation of ATZ, as well as, the percentage of mineralization, an experimental design was performed based on factorial design 23 methodology with center-point analysis. Total organic carbon (TOC) analyses and High-Performance Liquid Chromatography (HPLC) were employed to evaluate the efficiency of ATZ mitigation. The optimal conditions were achieved at an ozone flow rate of 0.4 mL/min, oxidation time = 30 min, and pH=8 where 100 % of ATZ was degraded and the highest percentage of mineralization was obtained (25.61 %). The potential toxicity of the residual concentration of ATZ was obtained by comparing with the values predicted by the QSAR tool, by comparing the outcomes. It was possible to come to the conclusion that the approach had positive implications for environmental safety. The values obtained are below the values considered toxic in aquatic environments, in almost all experiments. Low-concentration byproduct formation suggests that the degradation routes lead to low-hazardous concentrations of compounds for the environment. This implies the ozone treatment strategy might offer a long-term remedy for the ATZ.

Occurrence, Toxicodynamics, and Mechanistic Insights for Atrazine Degradation in the Environment

Occurrence, Toxicodynamics, and Mechanistic Insights for Atrazine Degradation in the Environment

Biochar modification accelerates soil atrazine biodegradation by altering bacterial communities, degradation-related genes and metabolic pathways

Atrazine is one of the most used herbicides, posing non-neglectable threats to ecosystem and human health. This work studied the performance and mechanisms of surface-modified biochar in accelerating atrazine biodegradation by exploring the changes in atrazine metabolites, bacterial communities and atrazine degradation-related genes. Among different types of biochar, nano-hydroxyapatite modified biochar achieved the highest degradation efficiency (85.13 %), mainly attributing to the increasing pH, soil organic matter, soil humus, and some enriched indigenous bacterial families of Bradyrhizobiaceae, Rhodospirillaceae, Methylophilaceae, Micrococcaceae, and Xanthobacteraceae. The abundance of 4 key atrazine degradation-related genes (atzA, atzB, atzC and triA) increased after biochar amendment, boosting both dechlorination and dealkylation pathways in atrazine metabolism. Our findings evidenced that biochar amendment could accelerate atrazine biodegradation by altering soil physicochemical properties, microbial composition and atrazine degradation pathways, providing clues for improving atrazine biodegradation performance at contaminated sites.

Impact of superabsorbent hydrogels on microbial community and atrazine fate in soils by 14C-labeling techniques

The accumulation of atrazine in soils can create environmental challenges, potentially posing risks to human health. Superabsorbent hydrogel (SH)-based formulations offer an eco-friendly approach to accelerate herbicide degradation. However, the impact of SHs on soil microbial community structure, and thus on the fate of atrazine, remains uncertain. In this study, a radioactive tracer was employed to investigate the influence of SHs on microbial communities and atrazine transformation in soils. The results revealed that the mineralization of atrazine in active soils was considerably greater than that in sterilized soils. Atrazine degradation proceeded rapidly under SH treatment, indicating the potential of SH to accelerate atrazine degradation. Furthermore, SH addition did not alter the atrazine degradation pathway in soils, which included dealkylation, dechlorination and hydroxylation. The relative abundance of dominant microbial population was influenced by the presence of SHs in the soil. Additionally, SH application led to an increased relative abundance of Lysobacter, suggesting its potential involvement in atrazine degradation. These findings reveal the significance of soil microorganisms and SH in atrazine degradation, offering crucial insights for the development of effective strategies for atrazine remediation and environmental sustainability.

Carbon-14 labeled transformation of atrazine in soils: Comparison of superabsorbent hydrogel coating and technical material

Atrazine exhibits adverse effects on diverse organisms in both terrestrial and aquatic environments, even though it effectively targets specific organisms. This study employed superabsorbent hydrogels to coat 14C-atrazine coupled with a four-compartment model to determine the fate of this herbicide in three oxic soils over a 100-day incubation period. Mineralization of atrazine was limited in all soils, with rates remaining below 3.5 %. The encapsulation treatment reduced mineralization of atrazine in soil A and soil B. Bound residues ranged from 26.1 to 43.6 % at 100 d. The encapsulation treatment enhanced the degradation of atrazine and reduced the content of deethylatrazine in soil A, but significantly increased the content of deisopropylatrazine in soil A and hydroxyatrazine in soil C. Using the obtained data, we also constructed a four-compartment model to clarify the relationships among the parent compound, degradation products, bound residues, and mineralization. This model accurately fits the fate of atrazine in the present work. Additionally, the correlation study suggested that both soil parameters and superabsorbent hydrogels played significant roles in influencing atrazine transformation. These findings serve as a reference for evaluating the environmental impact of superabsorbent hydrogels in atrazine pollution reduction and offer a foundational model approach for a comprehensive understanding of organic pollutants.

Laccase Immobilized on Arginine-Functionalized Boron Nitride Nanosheets for Enhanced Atrazine Degradation.

Enzyme-mediated systems have been widely employed for the biotransformation of environmental contaminants. However, the catalytic performance of free enzymes is restricted by the rapid loss of their catalytic activity, stability, and reusability. In this work, we developed an enzyme immobilization platform by elaborately anchoring fungal laccase onto arginine-functionalized boron nitride nanosheets (BNNS-Arg@Lac). BNNS-Arg@Lac showcased ∼75% immobilization yield and enhanced stability against fluctuating pH values and temperatures, along with remarkable reusability across six consecutive cycles, outperforming free natural laccase (nlaccase). A model pollutant, atrazine, was selected for a proof-of-concept demonstration, given the substantial environmental and public health concerns in agriculture runoff. BNNS-Arg@Lac-catalyzed atrazine degradation rate was nearly twice that of nlaccase. Moreover, BNNS-Arg@Lac consistently demonstrated superior atrazine degradation in synthetic agricultural wastewater and various mediator systems compared to nlaccase. Comprehensive product analysis unraveled distinct degradation pathways for BNNS-Arg@Lac and nlaccase. Overall, this research provides a foundation for the future development of enzyme-nanomaterial hybrids for degrading environmental chemicals and may unlock new potential for green and efficient resource recovery and waste management strategies.

Synthetic Studies of Aluminum-Doped Zn0.5Mn0.5AlxFe2−xO4 Ferrite for Photocatalytic Degradation of Atrazine Under Visible Light

Synthetic Studies of Aluminum-Doped Zn0.5Mn0.5AlxFe2−xO4 Ferrite for Photocatalytic Degradation of Atrazine Under Visible Light

The influence of vermicompost on atrazine microbial degradation performance and pathway in black soil, Northeast China

The atrazine (ATR) is extensively used in dryland crops like corn and sorghum in black soil region of Northeast China, posing ecological risks due to toxic metabolites. Vermicompost are known for soil organic pollution remediation but their role in pesticide degradation in black soil remains understudied. The influence of vermicompost on the microbial degradation pathway of atrazine was assessed in this study. Although vermicompost didn't significantly boost atrazine removal, they notably aided in primary metabolite degradation, hydroxyatrazine (HYA), deisopropylatrazine (DIA), and deethylatrazine (DEA), reducing their content by 38.67 %. They also altered the soil microbial community structure, favoring atrazine-degrading bacteria like Proteobacteria, Firmicutes, and Actinobacteria. Five secondary degradation products were identified in vermicompost treatments. Atrazine degradation occurred via dechlorination, dealkylation, and deamination pathways mainly by Nocardioidacea, Streptomycetaceae, Bacillaceae, Sphingomonadaceae, Comamonadaceae and Nitrososphaeraceae. pH and available nitrogen (AN) influenced microbial community structure and atrazine degradation, correlating with vermicompost application rates. Future black soil remediation should optimize application rates based on atrazine content and soil properties.

Degradation mechanism of atrazine in water by permutit loaded Fe and Cu oxides in a multi-electrode dielectric barrier discharge reactor

In this paper, the degradation of ATZ (Atrazine) in water by a catalyst-filler synergistic multi-electrode DBD (Dielectric barrier discharge) reactor was investigated.The results showed that 1O2, ·O2- and ·OH played a major role in the degradation process of ATZ. The addition of catalyst filler accelerated the removal efficiency of ATZ, and the removal efficiency of ATZ in Fe2O3/Permutit+DBD, CuO/Permutit+DBD, and Permutit+DBD were 95.76 % at the input voltage, gas flow rate, dosing volume, and processing time of 34 kV, 100 L/h, 1 g, and 15 min, respectively, 94.85 % and 91.54 %, which was 15 min shorter than the processing time of DBD system alone. Eight major degradation products were detected by high-resolution mass spectrometry, and their possible degradation pathways were inferred by combining with the DFT, and their intermediate products were found to be less acutely toxic and less chronically toxic than the parent ATZ by the ECOSAR toxicity analysis software.

Acid-modified hydrochar for higher biodegradation rate of atrazine in various conditions by Paenarthrobacter sp. KN0901: Higher cell viability and bacterial number

Microbial remediation is a viable and eco-friendly approach for decontaminating pollution. However, its effectiveness can be limited by the microorganisms’ survival and growth in changing environments. Hydrochar materials have been utilized in this study to increase the growth and atrazine degradation capabilities of Paenarthrobacter sp. KN0901, a strain capable of atrazine biodegradation. Acid-modified hydrochars exhibited a higher carbonation rate, specific surface area, and number of defect sites compared to raw hydrochar. Following three days of incubation at 15 °C, the atrazine degradation rate increased from 90.7 % to 98.2 % when utilizing H3PO4-modified hydrochar (PHC). Additionally, the addition of PHC resulted in an increase in both bacterial concentration and cell viability of strain KN0901, by 1.6 and 1.4 times, respectively. Under various conditions, including temperatures of 4 ºC and 35 ºC, as well as pH levels of 5 and 9, and dd·H2O media, PHC exhibited a significant enhancement in atrazine degradation and cell viability of strain KN0901. Furthermore, PHC demonstrated the ability to sustain high proliferation and viability of strain KN0901 over five cycles, indicating its remarkable stability and biocompatibility. This study offers a new perspective on the development and application of bioremediation approaches in restoring atrazine-polluted environments, even under challenging conditions.

Degradation of Three Herbicides and Effect on Bacterial Communities under Combined Pollution.

Pesticide residues in soil, especially multiple herbicide residues, cause a series of adverse effects on soil properties and microorganisms. In this work, the degradation of three herbicides and the effect on bacterial communities under combined pollution was investigated. The experimental results showed that the half-lives of acetochlor and prometryn significantly altered under combined exposure (5.02-11.17 d) as compared with those of individual exposure (4.70-6.87 d) in soil, suggesting that there was an antagonistic effect between the degradation of acetochlor and prometryn in soil. No remarkable variation in the degradation rate of atrazine with half-lives of 6.21-6.85 d was observed in different treatments, indicating that the degradation of atrazine was stable. 16S rRNA high-throughput sequencing results showed that the antagonistic effect of acetochlor and prometryn on the degradation rate under combined pollution was related to variation of the Sphingomonas and Nocardioide. Furthermore, the potential metabolic pathways of the three herbicides in soil were proposed and a new metabolite of acetochlor was preliminarily identified. The results of this work provide a guideline for the risk evaluation of combined pollution of the three herbicides with respect to their ecological effects in soil.