Degradation Of Atenolol Research Articles

Novel Catalyst-free Activation of Chlorine by Visible Light for Micropollutant Abatement

This study systematically investigated the direct activation of chlorine by visible light emitting diode (Vis-LED). Vis-LED could effectively activate chlorine to degrade micropollutants with degradation efficiency and pseudo-first-order degradation rate constant range of 64.3%-100% and 0.0340-0.195min-1, respectively. Quenching experiments and modeling results suggested that reactive chlorine species (RCS, including ClO•, Cl2•-, and Cl•) and hydroxyl radical (•OH) were involved in the degradation of atenolol (ATL). The contribution ratio of ClO•, free available chlorine, Cl•, Cl2•-, and •OH to ATL degradation were 58.7%, 17.4%, 15.6%, 1.8%, and 5.9%, respectively, in Vis-LED448/chlorine process. Moreover, the innate quantum yields of HClO and ClO- decreased from 0.229 and 0.0206 to 0.0489 and 0.0109mol·Einstein-1, respectively, as the wavelength increased from 448 to 513nm, leading to a decrease in ATL degradation, which was consistent with the model results. Experimental and modeling results have confirmed that ATL degradation decreased when pH increased from 4.0 to 9.0. Cl- had little effect on the degradation of ATL, while HA and HCO3- affected ATL degradation by scavenging reactive species and/or shielding effect. The concentration of disinfection by-products decreased with the increase of wavelength and pH. In summary, Vis-LED/chlorine is an efficient water treatment process even without a catalyst.

Sonolysis-ozonation and peroxidation method for removal of atenolol and amoxicillin in wastewater

Pharmaceutical compounds represent a significant challenge as water pollutants due to their persistence and adverse impacts on both the environment and human health. In the present study, the degradation of two pharmaceuticals- atenolol and amoxicillin was assessed in three advanced oxidation processes (AOPs), namely sonolysis, ozonation, and electrochemical peroxidation (ECP) under varying operational conditions using sewage as water matrix. The degradation of atenolol and amoxicillin was found to be over 95% at 1350W, contact time of 15min and pH of 3 during sonolysis. Ozonation proved very effective in the removal of both pharmaceuticals (>95%) in a short contact time of 30seconds using 0.32g/L-min ozone dose at pH 9. The removal of pharmaceuticals was highest at pH 9 compared to pH 4, and an ozone dosage of 0.21g/L-min was found to be adequate for achieving good degradation for both pharmaceuticals (>85%). In ECP, the maximum removal obtained for atenolol and amoxicillin was 94% and 91%, respectively, by using a current intensity of 10mA/cm2 and a hydrogen peroxide dose of 3mM. Ozonation rapidly degraded (>95%) atenolol and amoxicillin in just 30seconds, showcasing its superior performance.

Matching periodate peak absorbance by far UVC at 222 nm promotes the degradation of micropollutants and energy efficiency

Periodate (PI)-based advanced oxidation processes have gained increasing interest. This study for the first time elevates the light-activation capacity of PI by using far UVC at 222 nm (UV222/PI) without extra chemical inputs. The effectiveness and the underlying mechanisms of UV222/PI for the remediation of micropollutants were studied by selecting atenolol (ATL) as a representative. PI possessed a high molar absorption coefficient of 9480–6120 M−1 cm−1 at 222 nm in the pH range of 5.0–9.0, and it was rapidly decomposed by UV222 with first-order rate constants of 0.0055 to 0.002 s−1. ATL and the six other organic compounds were effectively degraded by the UV222/PI process under different conditions with the fluence-based rate constants generally two to hundred times higher than by UVA photolysis. Hydroxyl radical and ozone were confirmed as the major contributors to ATL degradation, while direct photolysis also played a role at higher pH or lower PI dosages. Degradation pathways of ATL were proposed including hydroxylation, demethylation, and oxidation. The high energy efficiency of the UV222/PI process was also confirmed. This study provides a cost-effective and convenient approach to enhance PI light-response activity for the treatment of micropollutants.

Paracetamol and Atenolol mitigation by Fenton and adsorption in-simultaneous process – Adsorbent regeneration and QSAR eco-toxicity prediction

This study aims to study the adsorption and oxidation of Paracetamol (PAR) and Atenolol (ATL) for application in water treatment. The pharmaceutical concentrations were monitored over time to assess the efficiency of the simultaneous process. The pH, contact time, and activated carbon (GAC) concentration were the variables evaluated in the adsorption process. While to the Fenton reaction, the proportion of Fe2+/H2O2 was the variable studied. Outcomes show that the most suitable conditions in the adsorption process to treat 40 mg/L of each pharmaceutical were achieved at 3 g of activated carbon (GAC) and 60 min.Tothe Fenton reaction, a ratio of 0.5 Fe2+/H2O2 was the most suitable condition. The results obtained in the simultaneous process were 17 % of mineralization, and 100 and 73.3 % of degradation of ATL and PAR. respectively. The formation of degradation products also decreased after treatment, suggesting the potential environmental safety of the combined treatment. A regeneration study was conducted to recuperate the GAC. The results showed that a GAC regeneration of 98 % was achieved after 4 cycles by the Fenton process, maintaining the degradation of pollutants evaluated at ∼ 99–98 %. Finally, a toxicity Quantitative Structure-Activity Relationship (QSAR) study was carried out to predict its potential toxicity, showing that it is feasible to conclude that the method has positive implications for environmental safety.

Performance and mechanistic studies of rapid atenolol degradation through peroxymonosulfate activation by V, Co, and bamboo carbon catalyst.

Developing the Co-based catalysts with high reactivity for the sulfate radical (SO4-·)-based advanced oxidation processes (SR-AOPs) has been attracting numerous attentions. To improve the peroxymonosulfate (PMS) activation process, a novel Co-based catalyst simultaneously modified by bamboo carbon (BC) and vanadium (V@CoO-BC) was fabricated through a simple solvothermal method. The atenolol (ATL) degradation experiments in V@CoO-BC/PMS system showed that the obtained V@CoO-BC exhibited much higher performance on PMS activation than pure CoO, and the V@CoO-BC/PMS system could fully degrade ATL within 5min via the destruction of both radicals (SO4-· and O2-··) and non-radicals (1O2). The quenching experiments and electrochemical tests revealed that the enhancing mechanism of bamboo carbon and V modification involved four aspects: (i) promoting the PMS and Co ion adsorption on the surface of V@CoO-BC; (ii) enhancing the electron transfer efficiency between V@CoO-BC and PMS; (iii) activating PMS with V3+ species; (iv) accelerating the circulation of Co2+ and Co3+, leading to the enhanced yield of reactive oxygen species (ROS). Furthermore, the V@CoO-BC/PMS system also exhibited satisfactory stability under broad pH (3-9) and good efficiency in the presence of co-existing components (HCO3-, NO3-, Cl-, and HA) in water. This study provides new insights to designing high-performance, environment-friendly bimetal catalysts and some basis for the remediation of antibiotic contaminants with SR-AOPs.

3D structure-functional design of a biomass-derived photocatalyst for antimicrobial efficacy and chemical degradation under ambient conditions.

Surface sterilization and hazardous chemical degradation under ambient conditions can provide significant benefits for public and environmental health. Materials with sterilization and chemical degradation capacity under sunlight can efficiently reduce infectious disease incidence rates and toxic chemical exposure. Utilizing renewable energy for sustainable sterilization and degradation is more desirable as it reduces the potential secondary contamination. Herein, we report functional structure design using lignin, a renewable carbon heterogeneous polymer, to synthesize a highly efficient and stable photocatalyst that degrades environmentally hazardous organic compounds rapidly. Through a hydrolysis reaction between Ti-OH and the hydroxyl groups of lignin, Ti-O-C and Ti-O-Ti bonds were established and a lignin based photocatalyst with a hollow sphere structure (Clignin@H-TiO2) was formed. The presence of a homozygous carbon modified TiO2 structure contributes to the enhanced photodegradation activity with solar light. The close hetero-interfacial contact between carbonized lignin and TiO2 further improves the photocatalytic efficiency by facilitating effective charge carrier separation. After synthesis optimization, the resulting Clignin@H-TiO2 photocatalyst exhibits excellent performance in the degradation of atenolol under solar light irradiation with 100% degradation within five minutes. Additionally, it efficiently removes approximately 50% of PFOA and kills about 90% of bacteria within three hours. The uniform distribution of lignin within the crosslinking structures ensures a durable carbon modified TiO2 framework, which remains stable after 10 cycles of usage. The robustness of the lignin-based photocatalyst enables incorporating the catalyst into diversified material formats and various usages. Coating of the photocatalyst onto device surfaces shows bacterial killing efficacy under sunlight. The photocatalysts based on lignin valorization present a green chemistry approach for environmental remediation and surface sterilization, which has long-term environmental protection benefits, with broad applications in toxin treatment and health protection against pathogen infection.

Simultaneous organic pollutant degradation and hydrogen peroxide production by molecular-engineered carbon nitride

A novel photocatalytic system was developed for the simultaneous degradation of organic contaminant and generation of H2O2 based on molecular-engineered carbon nitride (AQ-CNx). The AQ-CNx was synthesized by simultaneously introducing N defects and anthraquinone-2-carboxylic acid. Synergistically, the AQ-CNx exhibited a H2O2 production rate of 36.41 mM h−1 g−1, which is 7.87 times as that of CN. More importantly, atenolol (ATL) can promote H2O2 production, which in turn increases ATL degradation. Density functional theory (DFT) calculations demonstrate that N defects provide more sites for O2 adsorption and AQ acts as an electron-acceptor to facilitate the separation of photogenerated electrons and holes. Independent gradient model based on Hirshfeld partition (IGMH) analysis shows that van der Waals interaction between AQ-CNx and ATL enhances the degradation efficiency. This work provides a new idea for the effective degradation of pollutants and simultaneous generation of H2O2.

Insight into wavelength-dependent UVA-LED/chlorine process for micropollutant degradation: Performance, mechanism, and effects of water matrix

Ultraviolet A light-emitting diode (UVA-LED)-activated chlorine effectively degraded micropollutants at different irradiation wavelengths. Quenching experiments indicated that OH, reactive chlorine species (RCS), and O3 were the main reactive species for degradation of atenolol (ATL). Bezafibrate and ibuprofen, were used for the first time to jointly quantify the concentrations of Cl2− and ClO. Notably, O3 contributed most to the degradation of ATL (38.9%), following by OH (30.2%) and RCS (27.6%) at pH 7.0 by the UVA-LED/chlorine at 385 nm. ATL degradation increased with the decrease of wavelengths, due to the higher quantum yields of chlorine. The kobs of ATL was positively correlated to the quantum yield of chlorine at the UVA wavelength band. Higher light intensity could enhance the photolysis of chlorine, leading to enhanced ATL degradation. The protonated chlorine is more conducive to the degradation of ATL. Specifically, the contributions of OH, O3, and RCS to ATL degradation changed from 40.9%, 6.53%, and 41.0% at pH 4.0 to 11.6%, 59.9%, and 26.6% at pH 9.0, respectively. Cl− had no significant influence on ATL degradation, mainly due to the synergistic effect of different reactive species. HCO3− and HA inhibited ATL degradation owing to the quenching effect for reactive species and/or UV filtering effect. The primary transformation pathway of ATL included hydroxylation, chlorination, and bond-cleavage pathways based on the structures of the eight identified transformation products. Seven chlorinated disinfection by-products decreased as wavelengths and pH increased. The above results show that UVA-LED/chlorine might be an efficient process for water treatment.

Artificial Neural Networks and Genetic Algorithms: An Efficient Modeling and Optimization Methodology for Degradation of Atenolol Using Activated Persulfate with Ultrasound

Atenolol (ATN) is a slowly biodegradable antagonist β-blocker drug and remains in the environment for a long period of time. This drug has a harmful effect on the environment and human and animal bodies. In this study, using activated persulfate with ultrasound for the degradation of ATN was investigated. The effect of independent variables including pH, ATN concentration, persulfate dose, contact time, and ultrasonic power has been studied at 5 levels. Central composite design (CCD) was used for designing the experiments in Design Expert 11.0 software. The ATN concentration was measured using high-performance liquid chromatography (HPLC). Genetic algorithms (GA) and artificial neural network (ANN) were used for optimization and prediction, respectively. The results indicated that at the optimal conditions for the experiment (pH of 6.79, reaction time of 19 min, initial ATN concentration of 15.92 mg/L, US power of 109.56 W, and PS dose of 1317.88 mg/L), the highest ATN degradation efficiency was 98.9%. The ATN degradation could be represented by the pseudo-zero-order kinetics. Also, the data of ATN were well fitted with the ANN model (R2 = 0.98). The results showed that the best pH range to eliminate ATN is the near neutral range and the GA was found to be an effective tool to optimize the experimental conditions for the removal of ATN. The ultrasonic/persulfate process as a useful technique has a high potential to remove ATN from aqueous solutions.

Insight into the synergistic mechanism of sonolysis and sono-induced BiFeO3 nanorods piezocatalysis in atenolol degradation: Ultrasonic parameters, ROS and degradation pathways

Herein, BiFeO3 nanorods (BFO NRs) was synthesized as the piezoelectric catalyst. The synergistic mechanism of sonolysis and sono-induced BFO-piezocatalysis in atenolol degradation was revealed and the effect of ultrasonic parameters on it was investigated for the first time. The results indicated that 100 kHz was the optimal frequency for the sonolytic and sono-piezocatalytic degradation of atenolol in ultrasound/BFO nanorods (US/BFO NRs) system, with the highest synergistic coefficient of 3.43. The piezoelectric potential differences of BFO NRs by COMSOL Multiphysics simulations further distinguishing that the impact of cavitation shock wave and ultrasonic vibration from sonochemistry reaction (i.e., 2.48, −2.48 and 6.60 V versus 0.008, −0.008 and 0.02 V under tensile, compressive and shear stress at 100 kHz). The latter piezoelectric potentials were insufficient for reactive-oxygen-species (ROS) generation, while the former contributed to 53.93% •OH yield in US/BFO NRs system. Sono-piezocatalysis was found more sensitive to ultrasonic power density than sonolysis. The quenching experiments and ESR tests indicated that the ROS contribution in atenolol degradation followed the order of •OH > 1O2 > h+ > O2•- in US/BFO NRs system and 1O2 generation is exclusively dissolved-oxygen dependent. Four degradation pathways for atenolol in US/BFO NRs system were proposed via products identification and DFT calculation. Toxicity assessment by ECOSAR suggested the toxicity of the degradation products could be controlled.

Insights into degradation of pharmaceutical pollutant atenolol via electrochemical advanced oxidation processes with modified Ti4O7 electrode: Efficiency, stability and mechanism

A novel active Ce-doped Ti4O7 (Ti/Ti4O7–Ce) electrode was prepared and evaluated for improvement of the refractory pollutants degradation efficiency in Electrochemical advanced oxidation processes (EAOPs). The results showed that the addition of Ce in Ti/Ti4O7 electrode leading to great impact on •OH generation rate and electrode stability compared to pristine Ti/Ti4O7 electrode. Ti/Ti4O7–Ce electrode presented efficient oxidation capacity for pharmaceutical pollutant atenolol (ATL) in EAOPs, which could be attributed to the improvement of indirect oxidation mediated by electro-generated •OH, as the amount of •OH production was 16.5% higher than that in Ti/Ti4O7 within 120 min. The operational conditions greatly influenced the ATL degradation. The degradation efficiency of ATL increased as the current density, the degradation efficiency reached 100% under pH 4, but it just removed 81% of ATL under pH 10 after 120 min treatment. Results also suggested that the inhibiting effect from the ATL degradation was mostly associated with the decreased oxidation capacity induced by water hardness and natural organic matter (NOM). It displayed a satisfactory durability after 40 cycles of experimental detections in this research. The results of study suggested that Ti/Ti4O7–Ce was a promising electrode for the efficient degradation of PPCPs-polluted wastewater and provided constructive suggestion for the refractory pollutants of EAOPs.

A comparative study on Fe(III)/H2O2 and Fe(III)/S2O82− systems modified by catechin for the degradation of atenolol

The processes of Fe(III) activated persulfate (PS) and H2O2 modified by catechin (CAT) had been shown to be effective in degrading contaminants. In this study, the performance, mechanism, degradation pathways and products toxicity of PS (Fe(III)/PS/CAT) and H2O2 (Fe(III)/H2O2/CAT) systems were compared using atenolol (ATL) as a model contaminant. 91.0% of ATL degradation was reached after 60 min in H2O2 system which was much higher than that in PS system (52.4%) under the same experimental condition. CAT could react directly with H2O2 to produce small amounts of HO• and the degradation efficiency of ATL was proportional to CAT concentration in H2O2 system. However, the optimal CAT concentration was 5 μM in PS system. The performance of H2O2 system was more susceptible to pH than that of PS system. Quenching experiments were conducted indicating that SO4•- and HO• were produced in PS system while HO• and O2•- accounted for ATL degradation in H2O2 system. Seven pathways with nine byproducts and eight pathways with twelve byproducts were put forward in PS and H2O2 systems respectively. Toxicity experiments showed that the inhibition rates of luminescent bacteria were both decreased about 25% after 60 min reaction in two systems. Although the software simulation result showed few intermediate products of both systems were More toxic than ATL, but the amounts of them were 1–2 orders of magnitude lower than ATL. Moreover, the mineralization rates were 16.4% and 19.0% in PS and H2O2 systems respectively.

Zeolite-x encapsulated Ni(II) and Co(II) complexes with 2,6-pyridine dicarboxylic acid as catalysts for oxidative degradation of atenolol in an aqueous solution

ABSTRACT. Complexes of Co(II) and Ni(II) with 2,6-pyridine dicarboxylic acid (PydcH2) have been synthesized in the NaX (zeolite-X) nanopores. The formation of zeolite X encapsulated Co(II) and Ni(II) complexes ([M(pydcH)2]-NaX, [M = Co(II) and Ni(II])] were confirmed using spectroscopic methods of FT-IR, elemental analysis, XRD, FE-SEM, and TEM. It was affirmed that the encapsulation of complexes in NaX pores was formed without changes in the structure and shape of the zeolite. The oxidative degradation reaction of atenolol with hydrogen peroxide as an oxidant was performed in the presence of synthesized [M(pydcH)2]-NaX nanocomposites to study their catalytic activity. Therefore, oxidation of atenolol was performed under different conditions of catalyst, temperature, and time. Under optimal conditions, catalysts [Co(pydcH)2]-NaX and [Ni(pydcH)2]-NaX showed 82.3% and 71.1% activity of atenolol oxidation, respectively. These catalysts were stable after recovery and were used three more times. The results showed that these catalysts were reusable and had a reduction in the catalytic activity of less than ten percent.
 
 KEY WORDS: Zeolite-X, Nano porosity, Ion-exchange, Degradation of atenolol, 2,6-Pyridine dicarboxylic acid
 
 Bull. Chem. Soc. Ethiop. 2023, 37(3), 611-622. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i3.6

Catalytic ozonation of atenolol by Mn-Ce@Al2O3 catalysts: Efficiency, mechanism and degradation pathways

The aim of this study is to investigate the degradation efficiency and mechanism of atenolol (ATL) by catalytic ozonation with Al2O3 supported manganese-cerium mixed oxides (Mn-Ce@Al2O3), prepared by the impregnation-calcination method. The Mn-Ce@Al2O3 with 0.2 wt% manganese and 0.2 wt% cerium exhibited superior catalytic performance, resulting in complete ATL degradation and 63% mineralization. Mn-Ce solid solution on the surface significantly increased the specific surface area (279.5 m2/g). High amount of Ce3+, Mn3+ and high density of surface-active oxygen were contained on the surface of the catalyst, which facilitates the formation of oxygen vacancies and promotes the electron transfer in the catalyst. Combined with the low charge transfer resistance, surface protonated hydroxyl group, which was the active site of 0.2Mn-Ce@Al2O3, was more likely to adsorb ozone and decompose it into reactive oxygen species. O2·− and •OH were found to be the dominant active radicals for ATL degradation and mineralization that followed first-order kinetics. 17 intermediates were identified and 3 main degradation pathways were summarized, in order to provide reference for the complete mineralization of ATL.

Fe-TiO2 and Ag-ZnO mediated visible light photocatalysis for atenolol and acetaminophen removal – A comparative study and modeling

Globally, presence of pharmaceutical contaminants (PCs) in environment is a cause of concern. In this study, performance of the green synthesized nano-composites Fe-TiO2 and Ag-ZnO as visible light photocatalyst was evaluated by considering the removal of PCs viz., atenolol (ATL) and acetaminophen (ACT) spiked in treated domestic wastewater. Advanced oxidation process was performed in a batch photoreactor under visible radiation (650 nm). Removal of PCs were studied by considering four experimental factors viz., initial pH (4 to 12), initial ATL and ACT concentration (5 to 20 mg/L), visible photo catalyst concentration (500 to 1500 mg/L) and reaction time (40 to 120 min). Response surface methodology was used, regression models were developed (R2adj > 85 %), and optimization of factors was performed for the contaminant removal. It was found that, both Fe-TiO2 and Ag-ZnO performed well (ATL removal >63 %, and ACT removal >85 %) though, Fe-TiO2 had higher removal efficiency. It was found that the maximum removal of contaminants occurred when contaminant concentration was 5 mg/L, pH 8, catalyst concentration 1055 mg/L and reaction time 98 min. Characteristics of ATL and ACT photocatalytic degradation was performed and it was found that the contaminant removal was predominantly through the photocatalytic mechanism majorly due to OH oxidation pathway rather than adsorption and photolytic process. Further, the COD and TOC experiments indicated that >50 % mineralization could be achieved for both ATL and ACT, indicating that both the nanomaterial can be effectively used as a photocatalyst in the visible light radiation.

Atenolol degradation using hybrid processes of ultraviolet/peroxymonosulfate/microwave: modeling and optimization with artificial neural network and PSO algorithm

Atenolol degradation using hybrid processes of ultraviolet/peroxymonosulfate/microwave: modeling and optimization with artificial neural network and PSO algorithm

Efficient photocatalytic degradation of emerging pollutants by green synthesized Prussian blue analogue nanocomposite

AbstractWorldwide consumption, toxicity, and bioaccumulation of paracetamol (PCM) and atenolol (ATL) has drawn attention of researchers over last decades. A small portion of these drugs is absorbed by human body and rest of them is excreted through urine and feces to the environment (water bodies and soil) which might result in negative impacts. Nanocomposite of chromium oxide coupled with zinc hexacyanocobaltates (Cr2O3@ZnHCC) was synthesized by a green‐method using Sapindus mukorossi seed‐extract for the removal of targeted drugs. Microscopic and spectroscopic analysis of Cr2O3@ZnHCC showed uniformly incorporated prisms into cubic structure having ~75 nm particle size. Well‐characterized Cr2O3@ZnHCC and individuals (Cr2O3 & ZnHCC) were utilized for the degradation of PCM and ATL under direct sunlight and dark conditions. Highest degradation of targeted drugs (91%–94%) resulted at 20 mg L−1 concentration of pollutant, 25 mg of catalyst dose, and pH ~ 7 under daylight exposure (5 h). First‐order kinetics followed with a high adsorption capacity, Xm (13.4–14.5 mg g−1) value was obtained to confirm the strong binding with the pollutants. Moreover, Cr2O3@ZnHCC substantially suppressed the half‐life of targeted drugs (PCM: 0.6 h; ATL: 2.9 h) and converted them into safer‐small metabolites as confirmed by liquid chromatography‐mass‐spectrometry analysis, and the reduction of carbon content was confirmed by total organic carbon analysis. The charge separation mechanism was assisted by UV reflectance and photoluminescence data. The synthesized green‐nano photocatalyst displayed high reproducibility (up to 10th cycle), sensitivity, and stability during the degradation process which makes this a suitable candidate for industrial applications.

Facile fabrication of flower-like Ni-Co-Mn based LDHs and their superior catalytic performance for atenolol, nitrite and methanol

In this work, flower-like ternary nickel-cobalt-manganese hydroxide (NiCoMn-OH; NCM) was synthesized through a simple chemical bath deposition in presence of ammonium persulfate (APS) as a catalyst at low temperature. The structures and morphologies of the prepared materials were studied by various analytical methods. The mechanism for the formation of NCM flower-like nanostructure was investigated in detail by various optimization studies. The prepared materials were used for the tri-functional applications including catalytic atenolol (ATL) degradation, electrocatalytic oxidation of methanol and nitrite. The NCM catalyzed peroxomonosulfate (PMS) activation for ATL degradation was investigated. Moreover, when the NCM was used as an electrocatalyst for methanol electrooxidation, the NCM electrode exhibited an excellent catalytic rate constant (0.223 × 104 cm3.mol−1.s−1) and long-term stability. Further, as an electro-catalyst for nitrite electro-oxidation, the NCM exhibited good sensitivity (532 μA μM−1 cm−2), detection limit (1.0 μM (S/N = 3)), and wide linear range (up to 8.3 mM).

Insights into the Kinetics, Theoretical Model and Mechanism of Free Radical Synergistic Degradation of Micropollutants in UV/Peroxydisulfate Process

The degradation of acyclovir (ACY) and atenolol (ATL) in the UV/peroxydisulfate (UV/PDS) process has been systematically considered, focusing on the degradation kinetics, theoretical models, and reaction pathways via applying a microfluidic UV reaction system. The removal efficiencies of ACY and ATL were >94.8%, and the apparent degradation rate constants (kobs) were 0.0931 and 0.1938 min−1 at pH 6.0 in the UV/PDS system. The sulfate radical (SO4•−) and hydroxyl radical (•OH) were identified as the major reactive radicals. The pH-dependent reaction rate constants of ACY and ATL with •OH and SO4•− were measured via the competing kinetics. Meanwhile, the contributions of •OH and SO4•− for ACY and ATL degradation were calculated by the radical steady-state hypothesis, and the results revealed that SO4•− occupied a decisive position (>84.5%) for the elimination of ACY and ATL. The contribution of •OH became more significant with the increasing pH, while SO4•− was still dominant. Moreover, ACY and ATL degradation performance were systematically evaluated via the experiments and Kintecus model under different operational parameters (Cl−, Br−, HCO3−, NOM, etc.) in the UV/PDS process. Furthermore, the plausible reaction pathways of ACY and ATL were elucidated based on the Fukui function theory and ultra-performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) analysis. The UV/PDS process has been demonstrated to be an efficient and potential application for micropollutants mitigation.

Enhanced photo-Fenton assisted photocatalytic degradation of atenolol using a novel rGO embedded double Z-scheme nano-heterojunction: Mechanism, kinetics and toxicity studies

In this work, rGO-based ternary dual Z-scheme heterojunction (rGO/CuFe2O4/CdS/Bi2S3 QDs) was formulated for the effective photo-Fenton assisted photocatalytic degradation of a β-blocker, atenolol. The catalyst was synthesised via a simple co-precipitation/hydrothermal method and was characterized using XRD, XPS, FT-IR, SEM, TEM, PL, EIS, ESR, Raman and DRS. It exhibited about 76.5% degradation of atenolol in 360 min under visible light irradiation with a rate constant of 0.004 min−1 wherein the mechanism of enhanced activity was attributed to the formation of OH, h+ and photo-Fenton reaction; a possible mechanism was drafted. The intermediates were determined using GC–MS analysis delineating a plausible degradation pathway, the mineralization of atenolol being confirmed by TOC analysis. The catalyst was reusable and highly stable up to six cycles of degradation, as affirmed via XRD and XPS analysis. Further, the toxicity of the catalyst has been studied using the root cells of Allium cepa, and the degraded product and intermediates were assessed deploying ECOSAR software. Thus, the proposed work has potential which can be implemented in future for the large-scale purification of wastewater.