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.

Nanobiosensors based on tyrosinase with alkanethiols for detection commercial formulation of atrazine in artesian water samples applied in agriculture crop

This study aims to develop cantilever nanobiosensors functionalized with commercial tyrosinase enzymes and alkanethiols for the detection of a commercial formulation of atrazine in artesian water samples used in agricultural crops. Functionalization was carried out using the self-assembled monolayer (SAM) technique with different alkanethiols, namely, 16-mercaptohexadecanoic acid (16-MHDA) and 11-mercaptoundecanoic acid (11-MUA), in conjunction with commercial tyrosinase enzymes. Surface characterization techniques confirm the successful deposition of the sensing layer. The nanobiosensors exhibited the capability to detect various concentrations of atrazine in water, achieving high sensitivity with detection and quantification limits in the µg/L range, while maintaining 100 % reversibility. The enzyme retained 87 % and 80 % of its activity when immobilized on 16-MHDA and 11-MUA linkages, respectively. The response of cantilever nanobiosensors was stable after 13 min, with deflection values showing a direct proportional relationship with atrazine concentrations ranging from 0.001 to 100 µg/L. Both cantilever nanobiosensors demonstrated promising responses, with 11-MUA differing statistically (P<0.05) from 16-MHDA. The rapid detection of commercial atrazine was successfully conducted in real water samples collected directly during its application in crop fields. Consequently, the developed devices hold significant potential for practical use in the detection of atrazine in water, contributing to assessments of environmental quality.

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.

Efficiency and mechanism of high surface area mesoporous nanocast NC-LaCoO3 for activating peroxymonosulfate to degrade atrazine in water

A highly active perovskite is needed to activate peroxymonosulfate (PMS) into reactive oxygen species (ROS) to degrade organic pollutants in wastewater. High surface area LaCoO3 was fabricated via nano-casting employing mesoporous silica KIT-6 (a 3D material, first fabricated in Korea Advanced Institute of Science and Technology number 6) as the hard template. The NC-LaCoO3 showed a higher surface area (81.33 m2·g−1), pore volume (0.21 cm3·g−1) and pore diameter (7.78 nm), abundant acidic/basic sites, rich oxygen vacancies (OVs), and easily accessible active sites, as well as higher catalytic efficiency to degrade atrazine than uncast/citric acid-assisted perovskite (CA-LaCoO3), CA-La2O3 and Co3O4. Under the specific experimental condition (PMS concentration: 4.30 mM; catalyst dosage: 0.60 g·L−1; pH: 8.20; atrazine concentration: 10 mg·L−1; and room temperature), in 6.0 min, approximately 19.02 %, 56 %, 29.38 %, and 39.21 % of atrazine were degraded by sole PMS, CA-LaCoO3/PMS, CA-La2O3/PMS and Co3O4/PMS respectively, while it was completely degraded in 4.0 min in NC-LaCoO3/PMS. Moreover, 0.06 mg/L leaching of cobalt was detected during oxidation in the NC-LaCoO3 /PMS process. The NC-LaCoO3 depicted stable catalytic efficiency after six recycling terms. Radical scavengers depicted that SO4•− and •OH were produced as the main reactive species at the initial phase of the catalytic reaction, and subsequently, O2•− and 1O2 were generated as the secondary oxidative species. A comparatively dominant inhibitory effect of methanol compared to TBA suggested that SO4•− was mainly involved in atrazine degradation. XPS, EPR, in-situ ATR-FTIR, EIS, LSV, and chronoamperometric measurements were employed to explore the catalytic reaction mechanism. High catalytic efficiency was ascribed to better textural properties, diffusion-friendly structure, rich oxygen vacancies, and radical species. This research suggests that perovskites with a range of A and B metals can be synthesized by nanocasting using high surface area templates for advanced oxidation processes, especially PMS activation, to remediate organic wastewater.

Immobilization of zirconium-modified activated carbon in an alginate matrix for the removal of atrazine: Preparation, performances and mechanisms

As an organic herbicide widely used in agriculture, atrazine has the characteristics of environmental persistence, high mobility and long half-life period, posing potential risks to the ecological environment. The materials commonly used to remove atrazine are powdered activated carbon and its modified materials, which have problems such as difficulty in recycling and secondary contamination. In order to solve the above problems, in this study, a new functional material EI-Zr@AC was prepared by immobilizing zirconium-modified activated carbon powder (Zr@AC) in an alginate matrix via the embedding immobilization (EI) technique, and was employed for removing atrazine in water. At the optimal preparation conditions of 2.5 % sodium alginate, 4.0 % CaCl2, 1.0 % Zr@AC and 2.0 % bentonite, the prepared EI-Zr@AC beads had the characteristics of high porosity, dense reticulation, and a large number of functional groups with optimal mechanical strength and mass transfer properties. When solution pH 3.0, temperature 25°C, and EI-Zr@AC dosage of 16 g/L, the removal efficiency of atrazine by EI-Zr@AC was 91.9 %. It showed that the atrazine removal by EI-Zr@AC was mainly the chemisorption and multimolecular layer adsorption. In addition, the EI-Zr@AC could be recycled after simple recycling method, and the removal of atrazine at 5.0 mg/L by the beads was still 55.5 % after five cycles, and the structure of the beads remained intact and Zr ion leaching rate was very low. The results showed that EI-Zr@AC was a kind of environmental remediation material with high application value.

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.

Screening of Atrazine Tolerant Aquatic Plant and Roles of Plant Growth Regulators on Plant Growth and Atrazine Tolerance

The extensive use of atrazine to control weeds in agricultural areas has contaminated atrazine in surface water and groundwater. Atrazine contamination in water resources causes human health concerns. Thus, this study investigated the possible use of aquatic plants for removing atrazine from contaminated water. The experiment was performed under plant nursery conditions and divided into two parts: (1) the atrazine-tolerant plants were screened, and (2) the most atrazine-tolerant plant was used for atrazine phytoremediation stimulated by plant growth regulators. The results showed that atrazine was toxic to all aquatic plants, as the dry weight of the plants was significantly decreased when exposed to 20 mg/L of atrazine (P&lt;0.05). Based on five aquatic plants grown under 2.5–20 mg/L atrazine-contaminated water, &lt;i&gt;Azolla microphylla&lt;/i&gt; Kaulf. was the most tolerant aquatic plant and was more suitable for use in atrazine phytoremediation than the other aquatic plants (&lt;i&gt;Ceratophyllum demersum&lt;/i&gt; L., &lt;i&gt;Eichhornia crassipes&lt;/i&gt; (Mart.) Solms, &lt;i&gt;Hydrilla verticillata&lt;/i&gt; (L. f.) Royle, and &lt;i&gt;Salvinia cucullata&lt;/i&gt; Roxb. ex Bory). The total chlorophyll, carotenoid, and proline contents in the biomass of &lt;i&gt;A. microphylla&lt;/i&gt; cultured in 2.5–20 mg/L of atrazine did not significantly differ between the atrazine concentrations (P&gt;0.05). Meanwhile, the proline contents in the other four aquatic plants increased with increasing atrazine concentrations, and the chlorophyll content significantly decreased with an increase in the atrazine concentration. However, &lt;i&gt;A. microphylla&lt;/i&gt; could not remove atrazine from contaminated water, and the application of plant growth regulators (6-benzyladenine, gibberellic acid, indole-3-butyric acid, and salicylic acid) did not improve the atrazine removal from water. Atrazine in the water was around 21–26 mg/L on day five of &lt;i&gt;A. microphylla&lt;/i&gt; cultivation compared to the initial concentration (25 mg/L). Using a plant growth regulator was ineffective for stimulating growth and atrazine removal by &lt;i&gt;A. microphylla&lt;/i&gt;. Future research should explore other potential mechanisms for enhancing atrazine removal by &lt;i&gt;A. microphylla&lt;/i&gt;.

Fabricated layered g-C3N4 nanosheets for high efficiency photocatalytic degradation of atrazine：Insight into terminal-NHx in-situ activation of H2O2

It is well known that graphite-like carbon nitride (g-C3N4) is a good photocatalyst for in-situ the production of H2O2. However, how to activate H2O2 generating the strong oxidizing ·OH is the key factor to affect the degradation of pollutants. In this paper, the layered g-C3N4 nanosheets were prepared by using urea and H2O with different mass ratios and calcined in Muffle furnace by one-step synthesis method. The morphology, composition and structure of photocatalysts were analyzed, indicating that the as-prepared L-g-C3N4-7 had abundant edge regions in comparison with L-g-C3N4 made by solid urea. The photocatalytic performance of g-C3N4 nanosheets was investigated with atrazine (ATZ) as the target pollutant in water. The results revealed that the prepared L-g-C3N4-7 exhibited the best photocatalytic activity in visible light (λ ≥ 420 nm). The degradation of 1.0 mg/L ATZ reached over 96% after 3 hours and the photocatalytic degradation rate constant (k) was 6.8 times than that of L-g-C3N4 photocatalyst. In addition, under the same conditions, the H2O2 production of L-g-C3N4-7 was 4.5 times than that of L-g-C3N4 photocatalyst. Based on the capture experiments of free radicals, it was found that the contribution rate of ·OH in L-g-C3N4-7 photocatalytic increased to 17 % compared to 4 % of L-g-C3N4 photocatalyst during the degradation of ATZ. The ·OH quantitative experiment indicated that the L-g-C3N4-7 photocatalyst could obviously activate H2O2 to generate ·OH and the amount of ·OH was 2.5 times than that of the L-g-C3N4 photocatalyst. More importantly, a large amount of terminal-NHx (14.6 %) in L-g-C3N4-7 was measured by the XPS, FT-IR and zeta potential. The additive H2O2 adsorption experiment in the dark was used to confirm terminal-NHx sites of L-g-C3N4-7 photocatalyst, which was beneficial to adsorb and activate H2O2. The results illustrated that the L-g-C3N4-7 photocatalyst with rich edge regions and terminal-NHx had the characteristics of in-situ the activation of H2O2 to generate ·OH. The findings suggest that designing and developing efficient g-C3N4 photocatalysts pave a new avenue for activating in situ self-synthesizing H2O2 and the removal of atrazine in water.

LaCoO3/SBA-15 as a high surface area catalyst to activate peroxymonosulfate for degrading atrazine in water

An efficient perovskite-based heterogeneous catalyst is highly desired to activate peroxymonosulfate (PMS) for removing organic pollutants in water. A high surface area PMS-activator was fabricated by loading LaCoO3 on SBA-15 to degrade atrazine (ATR) in water. The LaCoO3/SBA-15 depicted better textural properties and higher catalytic activity than LaCoO3. In 6.0 min, atrazine (ATZ) degradation in the selected LaCoO3/SBA-15/PMS system, LaCoO3, adsorption by LaCoO3/SBA-15, sole PMS processes reached approximately 100%, 55.15%, 12.80%, and 16.65 % respectively. Furthermore, 0.04 mg L−1 Co was leached from LaCoO3/SBA-15 during PMS activation by LaCoO3/SBA-15. The LaCoO3/SBA-15 showed stable catalytic activity after reuse. The use of radical scavengers and electron paramagnetic resonance spectroscopy (EPR) demonstrated that ROS such as 1O2, O2•−, •OH, and SO4•− were generated by PMS activated by LaCoO3/SBA-15 owing to redox reactions [Co2+/Co3+, and O2−/O2]. EPR, XPS, ATR-FTIR, EIS, LSV, and chronoamperometric measurements were used to explain the catalytic mechanism for PMS activation. Excellent atrazine degradation was due to high surface area, porous nature, diffusion-friendly structure, and ROS. Our investigation proposes that perovskites with different A and B metals and modified perovskites can be loaded on high surface area materials to activate PMS into ROS.

Effect of Tetramethylurea (TMU) on Polysulfone Membrane Performance for Atrazine-containing Wastewater Treatment

Tetramethylurea (TMU) is a good solvent for organic substances and has received little attention as compared to other solvents. The TMU is a polar solution and is one of the molecules with an amphiphilic character. In the present work, an attempt has been made to use TMU as an additive in the preparation of nanofiltration membranes to improve the hydrophilicity of the membrane. The polysulfone membrane has been modified by incorporating different concentrations of TMU (0, 0.5, and 1 wt.%) in order to check the rejection of atrazine in water. This study aim is to optimize the conditions to enhance the flux and the rejection of atrazine. It was observed that the rejection of atrazine was enhanced when feed pH changed to acidic and with increasing the evaporation time. The prepared membranes were subjected to different analyses, such as contact angle measurement, FTIR, porosity, and mean pore size. The effect of the coagulation bath, evaporation time, and pH on the atrazine rejection was also studied. Membrane with 0.5 wt.% TMU shows maximum rejection of atrazine at the operating pressure of 15 kgf/cm2.

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.

Dual Chromatic Laser-Printed Microfluidic Paper-Based Analytical Device (μPAD) for the Detection of Atrazine in Water

Dual Chromatic Laser-Printed Microfluidic Paper-Based Analytical Device (μPAD) for the Detection of Atrazine in Water

Ultrasensitive assay of atrazine in food and water samples

AbstractAtrazine is the pesticide that is found in surface water sources more frequently than any other pesticide. Therefore, the paper describes ultrasensitive detection of atrazine from fruit and water samples, using on‐site screening platforms incorporating stochastic microsensors based on graphite powder modified with 4‐tert‐butylcalix [4] arene and with calix [4] arene‐25,26,27,28‐tetrol. Limits of determination of 0.1 fmol L−1 were recorded while the sensors could have been used on wide concentration ranges, between 0.1 fmol L−1 and 0.1 mmol L−1. Recoveries higher than 95.00 % were recorded when used for the assay of atrazine in water, fruits and vegetables.

Unraveling the effect of land use on the bacterioplankton community composition from highly impacted shallow lakes at a regional scale.

Bacterioplankton communities play a crucial role in global biogeochemical processes and are highly sensitive to changes induced by natural and anthropogenic stressors in aquatic ecosystems. We assessed the influence of Land Use Land Cover (LULC), environmental, and geographic changes on the bacterioplankton structure in highly connected and impacted shallow lakes within the Salado River basin, Buenos Aires, Argentina. Additionally, we investigated how changes in LULC affected the limnological characteristics of these lakes at a regional scale. Our analysis revealed that the lakes were ordinated by sub-basins (upper and lower) depending on their LULC characteristics and limnological properties. In coincidence, the same ordination was observed when considering the Bacterioplankton Community Composition (BCC). Spatial and environmental predictors significantly explained the variation in BCC, although when combined with LULC the effect was also important. While the pure LULC effect did not explain a significant percentage of BCC variation, the presence of atrazine in water, an anthropogenic variable linked to LULC, directly influenced both the BCC and some Amplicon Sequence Variants (ASVs) in particular. Our regional-scale approach contributes to understanding the complexity of factors driving bacterioplankton structure and how LULC pervasively affect these communities in highly impacted shallow lake ecosystems from the understudied Southern Hemisphere.

Polyaniline and polystyrene sulfonic acid modified on conductive biochar nanoparticle with strong signal enhancement for trace atrazine detection

A label and reagent free and cost effective immunosensing system was newly developed for detection of trace leveled atrazine in water. This was constructed by synthesis of polyaniline (PA) and polystyrene sulfonic acid (PSS) modified biochar (BC) nanoparticle composite (PA-PSS-BC) and coating them on screen printed electrode as conductive and electrochemically active layer, and covalently immobilizing anti-atrazine antibody on electrode for specific target binding. The low cost biochar from sugarcane was highly conductive and favorable for attaching PA and PSS due to large surface area and sp2 carbon structure. Crediting to dopant PSS, PA-PSS-BC achieved significant enhancement of redox current signal even in phosphate buffered saline of neutral pH compared to that of without PSS. And redox current of PA was extremely stable with negligible signal change even after twenty cycles repeated reactions owning to protection by BC. These essentially ensured sensing platform being sensitively performed in neutral solution with exemption of adding external redox reagent. As a result, fairly low concentrations of atrazine could be detected within 5 min, with limit of detection being 0.407 ng/L in a dynamic detection range varying from 1 to 100 ng/L. Moreover, the immunosensor exhibited reasonable signal recoveries for detecting trace leveled atrazine in real water samples, high selectivity, and good stability with dry and cold storage.

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.

Atrazine residue in waters of Ijebu-North local government, Nigeria: implications on human health, hematological, and biochemical parameters

Knowledge and implications of atrazine in waters from rural areas in Nigeria remain diminutive. Meanwhile, recent findings have shown presence of atrazine residue in water bodies. Atrazine level in six communities (Mamu, Oru, Ilaporu, Awa, Ijebu Igbo, and Ago-Iwoye) of Ijebu North local government, Ogun State, Nigeria using 69 hand-dug wells (HDWs), 40 boreholes (BHs) and four streams are monitored. Value of atrazine recorded was employed to appraise the implication on some hematological and biochemical parameters in relation to human health through dermal and ingestion contact using male albino rats. Highest atrazine of 0.08 mg/L was found in HDW of Ago-Iwoye out of 41 hand dug wells assessed, alongside 22 BH and four streams tested positive to atrazine, while the Oru documented lowest concentration with 0.01 mg/L. Ingestion and dermal hazard index (HI) were lower in adults than children and below acceptable limits in each community. Atrazine concentration at 0.01, 0.03, 0.04, and 0.08 mg/L in waters may not induce significant alteration in the hematological and some biochemical parameters of the exposed animal, while concentration at 0.04 and 0.08 mg/L might alter the blood glucose, albumin, and bilirubin. This is the first study to report atrazine in rural community waters in relation to human health in Nigeria.

Determination of Atrazine in Food, Water, and Synthetic Urine by Activated Carbon Cloth (ACC) Micro-Solid-Phase Extraction (µSPE) with High-Performance Liquid Chromatography – Diode Array Detection (HPLC-DAD)

Activated carbon cloth (ACC) was used as a micro solid phase extraction (µSPE) sorbent for the separation-preconcentration and determination of atrazine in water, juice, spice, and artificial urine by high-performance liquid chromatography-diode array detector (HPLC-DAD). The adsorbent mass was 10 mg, the adsorption-desorption duration was 90-s, and the proposed method can be applied to different matrices. The preconcentration factor of the method is 16.7. The limit of detection (LOD) and limit of quantification (LOQ) were 0.7 and 2.2 ng mL−1, respectively. The recovery values of the presented procedure were from 93 to 108% for real samples. This µSPE-HPLC-DAD protocol is practical and sensitive for atrazine and shows that activated carbon cloth is a highly effective adsorbent.

Determination of the Pesticides Ethoprophos and Atrazine in Water by T-Shaped Atmospheric Pressure Chemical Ionization (APCI) Mass Spectrometry (MS)

With the goal of enhancing the low sensitivity of the conventional atmospheric pressure chemical ionization (APCI) source due to the ion divergence, here is reported a T-shaped ion source to improve the sensitivity with a portable mass spectrometer for the rapid determination of the pesticides ethoprophos and atrazine in water. Compared with conventional APCI, the ion source improves the sensitivity for the analytes. The results show that the analysis requires less than 2 s, the limit of detection (LOD) is better than 0.1 and the relative standard deviation (RSD) is 16% at 1, 5, and 25 The recoveries of the analytes are between 80% and 130%, meeting the requirements for rapid pesticide determination in water.

Parametric modelling and analysis to optimize adsorption of Atrazine by MgO/Fe3O4-synthesized porous carbons in water environment

BackgroundPesticide contamination to water, continues to raise ecotoxicological and human concerns. Studying the application of green adsorbents for removing pesticides from water can significantly reduce ecotoxicological impacts and sustain reclamation of water bodies.ResultsThe current study investigated the adsorption capacity of MgO/Fe3O4 modified coconut shell biochar (MCSB) towards Atrazine removal in water. The prepared adsorbents were structurally constricted and obtained relative amount of mesopore spaces filled by nanoparticles which equally provided active occupancy/binding sites for Atrazine molecule deposition. Equilibrium isotherm studies under temperature regimes of 300 K, 318 K and 328 K were best described by the Freundlich isotherm (R2 = 0.95–0.97) with highest adsorption capacity corresponding to the highest temperature range (328 K) at (KF = 9.60 L mg−1). The kinetics modelling was best fitted to the pseudo second-order kinetic (R2 = 0.90–0.98) reaction pathways revealing that Atrazine uptake and removal occurred majorly over non-homogenous surfaces and high influence of surface functional groups in the process. Atrazine uptake by the adsorbent were mostly efficient within pH ranges of 2–6. Thermodynamics values of free energy ΔG° were negative ranging (ΔG° = − 27.50 to − 29.77 kJ mol−1) across the varying reaction temperature indicating an exothermic reaction, while enthalpy (ΔH°) (34.59 kJ mol) and entropy (ΔS°) (90.88 JK−1/mol) values were positive revealing a degree of spontaneity which facilitated Atrazine uptake. The adsorbents regeneration capacities over five cycles were observed to decrease proportionally with maximum yields up to 50–60%. Optimization of the adsorption condition by response surface modelling (RSM) and Central Composite Design (CCD) could reveal optimum conditions for Atrazine removal through interaction of different variables at pH = 12, adsorbate initial concentration at 12 mg L−1, adsorbate dosage at 0.5 g and reaction temperature at 54 °C. The overall mechanisms of the adsorption could be contributed by availability of surface functional groups on the MCSB surface through increase in hydrophilicity facilitating easy Atrazine molecule attachment via hydrogen bonding and improved surface complexation.ConclusionsThe as-synthesized MCSB adsorbent could uptake and remove Atrazine in water. A high pH, low concentration, low adsorbent dosage and high reaction temperature could be optimized conditions to attain highest Atrazine removal by the synthesized adsorbent.Graphical