Degradation Of Atrazine In Water Research Articles

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.

Design of a multi-electrode dielectric barrier discharge reactor and experimental study on the degradation of atrazine in water.

Atrazine (ATZ) is widely used in agriculture as a triazine herbicide, and its long-term use can cause serious environmental pollution. This paper independently designed a multi-electrode reactor, explored the output power and energy utilization efficiency of the dielectric barrier discharge reactor, and used the dielectric barrier discharge reactor to treat ATZ solution. The results showed that the degradation efficiency of ATZ was 96.39% at 30 min at an initial ATZ concentration of 14 mg/L, an input voltage of 34 kV, an input current of 1.38 mA, an aeration rate of 100 L/h, and a treatment water volume of 150 mL. The degradation of ATZ was significantly increased by the addition of persulfate (PS), Fe2+, and H2O2. After adding radical quenchers (EtOH, p-BQ, and FFA), the degradation efficiency of ATZ decreased, indicating that free radicals (•OH, •O2-, and 1O2) played a key role in the degradation process of ATZ.

Deep degradation of atrazine in water using co-immobilized laccase-1-hydroxybenzotriazole-Pd as composite biocatalyst

The efficient and green removal technology of refractory organics such as atrazine in water has been an important topic of research in water treatment. A novel membrane composite biocatalyst Lac-HBT-Pd/BC as prepared for the first time by co-immobilizing laccase, mediator 1-hydroxybenzotriazole (HBT) and metal Pd on functionalized bacterial cellulose (BC) to investigate the removal of atrazine and degradation of its intermediates under mild ambient conditions. It was found that atrazine could be completely degraded in 5 h by the catalysis of Lac-HBT-Pd/BC, and the removal rate of degradation intermediates from atrazine was about 85% after continuous catalysis, which achieved deep degradation of atrazine. The effect of electrochemical activity and radical stability of the membrane composite biocatalysts loaded with Pd was investigated. The possible degradation pathways were proposed by identifying and analyzing the deep degradation products of atrazine. The Lac-HBT-Pd/BC demonstrated deep degradation of atrazine and favorable reusability as well as considerable adaptability to various water qualities. This work provides an important reference for preparing new kinds of biocatalysts to degrade refractory organic pollutants in water.

Differential interference of copper with endophytic bacterial inoculation: Atrazine decontamination in Acorus tatarinowii and culture solution

To clarify the interference effects of inorganic ions, Acorus tatarinowii and endophytic bacterium Herbaspirillum huttiense (Hh) were combined to decontaminate atrazine pollution under different copper levels. This study verified inoculation effects and revealed the complicated processes of atrazine transformation in solutions. 35.9% leaf biomass was promoted by Hh inoculation, and the value was lowered to 7.87% by high doses of copper. The changing trend of leaf N, K, and S contents, and tiller numbers were consistent with that of leaf biomass. Hh injection improved atrazine accumulation by 43.5% in roots, and under copper interference, this value lowered to 10.6%. Hh promoted atrazine deethylation in plants, which was copper-dose dependent in different plant organs. In solutions, atrazine was conjugated with small-molecule secretions at m/z 118, detoxicated into 2-hxydroatrazine and 2-hydroxy-4-acetamido-atrazine, then the triazine ring opened. Copper interference had a more significant impact on residual atrazine conversion products than Hh inoculation treatments. Hh treatment promoted the ring-opening degradation of atrazine in water. The addition of high doses of copper ions promoted the oxidative process of atrazine while inhibiting its ring-opening transformation process in water.

Heterogeneous catalytic ozonation by amorphous boron for degradation of atrazine in water

As one of the most promising and practical advanced oxidation processes (AOPs), the catalytic ozonation is triggered by the active components of catalyst, which are usually derived from metals or metal oxides. To avoid the metal pollution from catalyst, here the amorphous boron (A-boron) is used as a metal-free catalyst for catalytic ozonation to produce free radicals for effective degradation of atrazine (ATZ), the world-widely used herbicide and also a widespread pollutant in environment. A-boron exhibits an outstanding performance for catalytic ozonation to remove ATZ from water. As A-boron is introduced into ozonation, the degradation efficiency in 10 min is promoted to 97.1%, much higher than that of 15.1% under ozonation. The mechanism is that the B–B bonds and internal suboxide B in A-boron serve as the main active sites to donate electrons to accelerate ozone decomposition to produce reactive oxygen species (ROS), including •O2− and 1O2, and further enhance ATZ degradation via ROS reactions. Moreover, the A-boron is still highly active with a degradation efficiency of ATZ over 95% in 10 min even after four successive cycles. This work shows A-boron could be an alternative for the active components of metal or metal oxide in catalytic ozonation.

The Fate of Atrazine in Tropical Environments: Photolysis, Acute Toxicity and Endocrine Disruptor Potential

Triazine herbicides are widely used both in Brazil and internationally and are frequently detected in natural environments and drinking water. This study assesses atrazine degradation through solar radiation under tropical conditions and determines the toxicity of the intermediates. Atrazine degradation is tested through ultrapure water, humic acid solution and natural water experiments, with exposure to sunlight to simulate a natural environment. A yeast estrogen screen (YES) assay and Artemia salina test are carried out during the abiotic degradation. The atrazine degradation depends on the radiation intensity, since the experiments conducted in the summer reached 50% after ca. 17 days. No significant variations in this herbicide concentration are observed after 90 days of exposure in the fall. Atrazine degradation is observed only in humic acid and is responsible for indirect photolysis. Intermediates, namely, desethylatrazine (DEA) and deisopropylatrazine (DIA), are identified and quantified at the μg L–1 level. Thus, with the degradation of atrazine in water, the medium toxicity may decrease, since DEA and DIA have mean effective concentrations that kill 50% of Artemia salina (EC50) similars to atrazine (13 mg L–1). No estrogenic activity in the YES is detected for atrazine and its metabolites. These findings evidence that radiation intensity and organic substances in tropical countries influence the half-life of pesticides in aquatic environments.

Degradation of atrazine in water by Bi2MoO6 and visible light activated Fe3+/peroxymonosulfate coupling system

In this study, the effects of ferric ion (Fe3+) on the degradation of atrazine (ATZ) in Bi2MoO6/peroxymonosulfate (PMS) system under visible light irradiation was investigated. With the addition of Fe3+, ATZ in the visible light/Bi2MoO6/PMS system degraded rapidly after 20 min treatment (removal rate > 99%). The enhancement of ATZ removal can be attributed to the role of Fe3+. As an electron transfer mediator, Fe3+ not only inhibits the recombination of photo-charges and prolongs the life of photogenerated carriers, but also promotes the activation of PMS by accelerating the electron transfer from Bi2MoO6 to PMS. The generation of •OH and SO4•− in the system was determined via electron paramagnetic resonance (EPR) technology and quenching experiments. Furthermore, the characterization of Bi2MoO6 before and after reaction, influence of the reaction parameters (i.e., catalyst and PMS dosages, Fe3+ and ATZ concentration, initial pH), influence of inorganic anions and humic acid, and the recyclability of catalyst in the vis/Bi2MoO6/PMS/Fe3+ system was also investigated. Additionally, the existence of Fe3+ also exhibits a wide selectivity for the degradation of different pollutants and high treatment efficiency. In general, the vis/Bi2MoO6/PMS/Fe3+ system demonstrated the potential as an efficient, economical, and environment-friendly water treatment process.

Enhanced degradation of atrazine in water by VUV/UV/Fe process: Role of the in situ generated H2O2

Vacuum ultraviolet/ultraviolet/Fe (VUV/UV/Fe) has been regarded as a new advanced oxidation process (AOP), but its kinetics and mechanism for pollutant degradation remain largely unknown. This work investigates the degradation of a typical pesticide, i.e. atrazine (ATZ), by VUV/UV/Fe. The results show that ATZ was efficiently degraded by VUV/UV/Fe and the pseudo first-order rate constant (ka) reached 1.01 min−1, which was 1.7 times as high as the sum of those by UV/Fe and VUV/UV. This synergistic effect observed during the VUV/UV/Fe process was attributed to effective utilization of the H2O2, which was generated in situ by VUV photolysis of water, via the Fenton-like reaction. The apparent production rate of H2O2 was 0.19 mM min−1 in VUV/UV process, but decreased dramatically to 0.07 mM min−1 with addition of 1.0 mM Fe3+, which confirms the consumption of H2O2 by the Fenton-like reaction. The addition of tert-butanol and 1,4-benzoquinone proves that HO2 generated via the Fenton-like reaction played an important role, albeit not as much as HO, in the degradation of ATZ by VUV/UV/Fe. The application of Fe3+ as the iron source was much more effective than that of Fe2+ for the degradation of ATZ by VUV/UV/Fe. ka was a concave function of the solution pH and reached the optimal value at pH 3.5. The four selected inorganic anions inhibited the ATZ degradation by VUV/UV/Fe in an order of SO42− < HCO3− < NO3− < Cl−. The release of Cl− caused by the substitute reaction of chlorine atom with reactive oxygen species accounted for only 17.8% of the removed ATZ. It demonstrates that VUV/UV/Fe is a promising treatment process for pollutant removal from water.

Robust nanocatalyst membranes for degradation of atrazine in water

Solid membranes for degradation of emerging contaminants such as atrazine is of significant interest for water engineering applications. In this study, nanocatalyst particles have been anchored on vertically-aligned carpet-like arrays of carbon nanotubes (CNT) grown on porous carbon foams. This hierarchical architecture combines the advantages of highly surface-active nanoparticles with the robust and reusable structural advantage of porous solid membranes suitable for water treatment devices. Three types of palladium-based nano-catalytic surfaces have been investigated: metallic palladium (Pd), Pd nanoparticle with a layer of oxide (PdO-coated Pd), and Pd nanoparticle coated with thin film of silver (Ag-Pd). Their catalytic activities have been compared by analysing the degradation rate of atrazine in water. It is noted that all three catalysts show high levels of atrazine degradation, with the PdO-coated nanoparticles showing the highest kinetics. These results demonstrate that hierarchical hybrid architectures can provide compact and powerful surface-active materials such as adsorbents and catalytic degradation devices in future water treatment applications.

Visible light photocatalytic degradation of herbicide (Atrazine) using surface plasmon resonance induced in mesoporous Ag-WO3/SBA-15 composite

Atrazine is one of the most extensively used herbicides. Being non-biodegradable in nature, it has a long half-life in water and hence it is prone to contaminate the water bodies and even seeps into the ground to pollute underground water. In this study, we developed a photocatalytic method for the degradation of Atrazine in water samples. Highly ordered mesoporous Ag-WO3/SBA-15 composites were tested as photocatalysts for the degradation of atrazine in water. It was found that 40% WO3 loading rendered an optimum surface area and material content in the SBA-15 template and hence favored the enhanced photocatalytic degradation of atrazine in water. The further addition of Ag onto the WO3/SBA-15 composite not only made this catalyst very effective in the most sought visible region due to solar energy harvesting, but also significantly reduced the electron hole recombination as evidenced by photoluminescence studies to enhance the degradation efficiency. As a result, the Ag-WO3/SBA-15 composite the photo-catalytic degradation of atrazine in water under visible radiation was significantly enhanced.

Ultraviolet–Visible Light–Sensitive High Surface Area Phosphorous-Fluorine–Co-Doped TiO2 Nanoparticles for the Degradation of Atrazine in Water

Conventional titanium dioxide (TiO2) materials can be activated only by ultraviolet (UV) light, which is only 4–5% of the whole solar spectrum. As a result, visible light (vis)–active TiO2-based photocatalysts have recently received significant attention in the field of TiO2 photocatalytic treatment and purification of water and air. This study reports the preparation of UV-visible light–active phosphorous (P)-doped, fluorine (F)-doped, and PF–co-doped anatase TiO2 nanoparticles via an innovative sol-gel method. Prepared nanoparticles were characterized by UV-vis diffuse reflectance spectroscopy, X-ray diffraction analysis, Raman spectroscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy (FTIR), and porosimetry analysis. Synthesized materials exhibited improved structural properties, including high surface area, small crystallite size, reduced band gap energy, mesoporous structure, and high porosity. Due to doping with P and F, light absorption of TiO2 in the visible light region was efficiently enhanced with effective band gap energy of 2.70 eV. Brunauer-Emmett-Teller (BET) surface area for PF–co-doped, P-doped, F-doped, and reference TiO2 nanoparticles was 212.0, 175.0, 88.8, and 79.7 m2/g, respectively. PF–co-doped TiO2 showed the highest photocatalytic degradation of atrazine, which could be attributed to the beneficial effects including small crystallite size, high BET surface area, and light absorption in UV-visible region, induced by co-doping of TiO2 with P and F. Finally, reaction intermediates were determined, which confirms the photocatalytic degradation of atrazine using the synthesized catalysts under UV-visible light illumination.

Quantum efficiencies of the photo-Fenton degradation of atrazine in water

An experimental work in a well-stirred batch recycling reactor for the photo-Fenton degradation of atrazine in water is presented. A study of the quantum efficiency is performed to assess the effectiveness of the photo-Fenton process on the atrazine degradation and total organic carbon (TOC) mineralization. Apparent and absolute quantum efficiencies of degradation and mineralization of an atrazine-based commercial herbicide are determined under different experimental conditions. Higher apparent efficiencies were found for both atrazine degradation and TOC mineralization when the ferric ion and hydrogen peroxide concentrations are increased. Because of the well known stability of the triazine ring, atrazine was not completely mineralized by the photo-Fenton process. However, a TOC reduction of 40% was achieved, being 62.5% of the maximum value that can be reached.

Removal of diquat and deisopropylatrazine from water by montmorillonite-(Ce or Zr) phosphate crosslinked compounds

The adsorption of diquat (1,1′-ethylene-2,2′-dipyridilium dibromide) and one intermediate compound of the degradation of atrazine in water, deisopropylatrazine, on two montmorillonite-(Ce or Zr) phosphate crosslinked compounds from aqueous solution under conditions of varied temperature (288 K and 308 K) has been studied. The experimental adsorption isotherms obtained for diquat on both adsorbents may be classified as H-type of the Giles classification which suggests that diquat molecules are strongly adsorbed on the samples. For the deisopropylatrazine, L-type isotherms were obtained for both montmorillonite-(Ce or Zr) phosphate compounds, which suggests a moderate affinity of this metabolite by the active sites of the adsorbents. The increase of temperature from 288 K to 308 K does not clearly affect the adsorption process of diquat on both adsorbents whereas the deisopropylatrazine adsorption decreases slightly as temperature increases possibly due to a mainly physical process. Fourier transform infrared (FTIR) spectroscopic studies reveal that at the pH generated by the adsorbents, the cationic herbicide interacts to a greater extent with the negative charged surface of the adsorbents than deisopropylatrazine. For both model compounds, the ceriummontmorillonite adsorbent shows the higher capacity of adsorption compared with zirconiummontmorillonite adsorbent.

Aqueous uv radiation and uv/h2o2oxidation of atrazine first degradation products: Deethylatrazine and deisopropylatrazine

The UV photolysis and H2O2/UV advanced oxidation of two intermediate compounds of the degradation of atrazine in water, deethylatrazine and deisopropylatrazine, have been studied. The influence of hydrogen peroxide and bicarbonate ion concentrations was observed both in organic-free water and in surface waters. Both UV photolysis and UV/H2O2 oxidation techniques lead to significant rates of elimination of these compounds, although they were lower in surface waters, likely due to the presence of natural radical scavengers. However, in the presence of 0.01 M bicarbonate ion, degradation rates were similar regardless of the type of water used. A kinetic study of both techniques was also conducted. Quantum yields and rate constants of the reaction between the hydroxyl radical and both intermediates were determined.