Degradation Of Ciprofloxacin Research Articles

Focusing on the interfacial charge transfer by carbon quantum dots from FeTiO3 perovskite for enhanced photocatalytic antibiotic degradation

Herein, FeTiO3 perovskite particles were functionalized with carbon quantum dots (CQDs) using ultrasonication followed by impregnation methods. The functionalization enhanced visible light-driven degradation of ciprofloxacin (CIP) antibiotic via extended light absorption, promoted separation rate of photogenerated carrier and increased oxygen vacancies. The FeTiO3/CQDs composite including 20 mL of CQDs degraded 68.4 % of CIP within 120 min whereas FeTiO3 itself only degraded CIP by 36.5 %. On the basis of the structural characterization, the successful introduction of CQDs was confirmed in the FeTiO3/CQDs composite. The increased ratio of oxygen species was proved by XPS and ESR measurements, and the improved charge transfer was supported by PL analysis. The degradation mechanism was identified via scavenger tests; super oxide radicals and holes were found dominant in the degradation reaction. Furthermore, the photocatalytic performance was boosted by adding two Fenton reagents to the reaction environment. The FeTiO3/CQDs composite catalyst also exhibited an excellent reusability and stability features. Accordingly, this study presented a novel and low-cost hybrid semiconductor as efficient and sustainable material for environmental purification under visible light irradiation.

Ultra-fast degradation of ciprofloxacin by the peroxymonosulfate activation using a Co/Al-LDH decorated magnetic hydrochar: Structural design, catalytic performance and synergistic effects

CoFe2O4/BHC-LDH3 catalyst was constructed by decoration of Co/Al layered double hydroxides (Co/Al-LDH) on bamboo hydrochar (BHC) loaded with magnetic CoFe2O4 to activate peroxymonosulfate (PMS) for ciprofloxacin (CIP) degradation. Taking advantage of structural modulation and synergistic effects between the multi-components, CoFe2O4/BHC-LDH3 demonstrated high efficient PMS activation and ultra-fast CIP removal (91.50 % within 10 min), compared with BHC (6.26 %), CoFe2O4 (26.32 %), and Co/Al-LDH (40.10 %). Both free radical (SO4–) and non-radical (1O2) were crucial during the degradation process, and a substantial decrease in aquatic toxicity of the intermediates was observed. Additionally, the stability of CoFe2O4/BHC-LDH3 in actual water environment was tested using a fixed-bed reactor, illustrating the CoFe2O4/BHC-LDH3 has good stability and anti-interference ability in long-term operation. Possible degradation pathways of CIP in the CoFe2O4/BHC-LDH3 + PMS system were proposed based on liquid chromatography-mass spectrometer analysis and density functional theory calculation. This work provides new strategies for hydrochar-supported catalyst synthesis for organic pollutants decomposition.

Mn-NSC co-doped modified biochar/permonosulfate system for degradation of ciprofloxacin in wastewater

Mn-Nitrogen-sulfur co-doped modified biochar (Mn-NSCX) is prepared by high-temperature pyrolysis and hydrothermal method, and its properties are analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). A metal-non-technical co-doping system was constructed and first used for PMS activation towards ciprofloxacin degradation. The results show that doping of Mn, N and S significantly improve the catalytic performance of activated PMS to degrade CIP, among which Mn-NSC2 exhibit the best catalytic performance, when the dosage of MN-NSC2 is 0.4 g·L−1, the concentration of PMS is 0.4 mmol·L−1, and the concentration of CIP is 20 mg·L−1. After 60 min, more than 99% of CIP can be removed, among which the CIP removal rate of BC/PMS is 43.6%, and the CIP removal rate of NSC5/PMS is 50.3%. The removal effect of CIP is greatly improved after the incorporation of manganese, attributing to the oxidation reaction between the PMS and manganese dioxide. The results of electron paramagnetic resonance (EPR) indicate that both free radicals (·SO4-,·OH) and non-free radicals (1O2) play important roles in the degradation of CIP, and 1O2 plays a foremost role in the degradation of CIP. Doping of Mn, N and S accelerate the electron transfer rate and improve the catalytic activity of the material. In this paper, the loading of metal oxides can increase the corresponding catalytic sites and promote electron transfer, thus promoting the ability of activated PMS to degrade organic pollutants. The metal modification not only improves the oxygen-containing groups of the material, but also promotes the activation of persulfate by metal oxidation on the surface of the material. A novel design and preparation strategy for catalyst is proposed to simultaneously achieve stable Mn-Nitrogen-sulfur co-doped modified biochar and improve the catalytic performance of biochar by adding Mn, S, and N.

Highly conductive Ti3C2 MXene reinforced g-C3N4 heterojunction photocatalytic for the degradation of ciprofloxacin: Mechanism insight

The extensive use of ciprofloxacin (CIP) poses a great threat to aquatic ecosystem, due to its potentially serious inhibitory effect on the microbial activity and low natural degradation rate. Photocatalytic degradation has emerged as a feasible method for treating CIP pollution. In this study, Ti3C2 reinforced g-C3N4 heterojunction material (MX/CN) was prepared using solvent drying method. The heterojunction composite accelerated the electron transfer rate, and the resulting MX/CN exhibited superior photocatalytic activity against CIP under visible light driving. The MX/CN sample achieved higher CIP photocatalytic removal rate of 97.8 %, 1.23 times higher than CN. Moreover, 6 %-MX/CN showed the best photocatalytic activity at pH = 7 when the initial concentration of CIP was 10 mg/L. Under neutral condition, the presence of Cl−, NO3−, and HCO3− reduced the degradation of CIP, where the addition of HCO3– caused a competed redox reaction with •OH in the system, resulting in a reduction of the CIP degradation efficiency to 30.9 %. The photocatalytic mechanism involving MX/CN was proposed according to the trapping experiments of active species, which confirmed that •O2− was the primary active component in photocatalytic degradation of CIP and h+ and •OH also played significant roles. Finally, cycling experiments using MX/CN showed that the CIP degradation efficiency maintained more than 90 % after five cycles.

Construction of Z-scheme heterojunction TiO2-ZnO@Oxygen-doped gC3N4 composite for enhancing H2O2 photoproduction and removal of pharmaceutical pollutants under visible light

In this study, the heterojunction photocatalyst of titanium dioxide-zinc oxide@oxygen-doped graphitic carbon nitride (TiO2-ZnO@OCN (TZ@OCN)) was synthesized using a simple and cost-effective hydrothermal self-assembly process. Characterization of the fabricated materials revealed that the incorporation of TiO2 and ZnO as inherent semiconductors along with the oxygen doping has effectively broadened the absorption spectrum of gC3N4, which can promote the electron generation and provide more active sites for O2 and H+ adsorption. It is noteworthy that the mentioned structure modification resulted in a superior H2O2 production rate among gC3N4-based photocatalysts with up to 3.11 mM.g−1 under visible light irradiation. Moreover, a valence band shifting from 1.57 to 2.91 eV upon doping oxygen atoms also elucidated the participation of active species in the photocatalytic degradation of ciprofloxacin (99.7 %, k = 0.030 min−1) and tetracyline (94.6 %, k = 0.017 min−1), in which superoxide radicals (•O2−) were shown to play a major role in removing the antibiotic. Besides, a Z-scheme heterojunction mechanism is additionally suggested, demonstrating the effectiveness of electron-hole pair splitting in the oxidation of antibiotics. Conclusively, the results show a novel and feasible modification pathway to enhance the photocatalytic activities of gC3N4 and other advanced semiconductor catalysts, especially for eliminating antibiotics and generating H2O2 within aqueous media.

Bi2O2CO3-coating on beverage-derived carbon microspheres to achieve highly-efficient photocatalysts for ciprofloxacin degradation

Facilitating photocarrier separation is deemed to be crucial for enhancing photocatalytic activity of photocatalysts, which has drawn considerable attention recently. Herein, we have adopted soft beverage-derived carbon materials to modify Bi2O2CO3 (BOC) and realize highly-efficient enhancement in the photodegradation activity. Take carbonized Fanta (labeled as CFT, which are shaped like microspheres) as an example, BOC nanoflakes are coated on the CFT microspheres to obtain core-shell structured CFT@BOC composites. The photodegradation experiment, performed under simulated-sunlight irradiation for ciprofloxacin (CIP) degradation, demonstrates that the optimal composite 9CFT@BOC has a photodegradation activity increased by 8.75 times over that of single BOC. This phenomenon can be interpreted because of the efficient electron transfer from BOC to CFT and hence the decreasing recombination of the photoelectrons/photoholes. Systematic experimental and density functional theory (DFT) were carried out to elucidate the photocatalytic mechanism of the CFT@BOC composites as well as the CIP decomposition behavior. We have also carbonized other soft beverages (e.g., Dayao, Mirinda and Cola) to modify BOC and observed similar phenomenon for photocatalysis enhancement. The present study offers a new insight for designing excellent photocatalysts in environmental remediation.

Ciprofloxacin Degradation by Peroxymonosulfate Activated by Pulsed Electric Field

Ciprofloxacin Degradation by Peroxymonosulfate Activated by Pulsed Electric Field

Development of highly efficient Ce(MoO4)2/g-C3N4 composite for the photocatalytic degradation of methylene blue and ciprofloxacin under visible light

Semiconductor based photocatalysts are reflected to be an effective way to solve the global energy demand and environmental remediation issues. We have successfully fabricated using a hydrothermal method for a new binary Ce(MoO4)2/g-C3N4 (CeM/g-CN) composite. The synthesized CeM/g-CN composite has displayed improved photocatalytic degradation performance towards the antibiotic pollutant of ciprofloxacin (CIP) and methylene blue (MB) under visible-light. The structure, composition, morphology, and optical absorption properties of synthesized materials were characterized by different techniques like PXRD, FE-SEM-EDX, TEM, XPS, FT-IR, PL, TRFL, BET, and UV–vis DRS, respectively. Our results conclude that, among the series of synthesized compounds, CeM/g-CN-20 composite has shown significant photocatalytic degradation efficiency for two different organic pollutants, those are CIP and MB. The degradation percentage and rate constant of CIP and MB for optimized CeM/g-CN-20 composite were 78.11 % and 11 × 10−3 min−1, 87.56 %, and 15.6 × 10−3 min−1 in 140 min under visible-light irradiation. The degradation percentage and rate constant were very high compared to pristine CeM, g-CN, and other composites. The enhancement in the degradation ability of CeM/g-CN-20 may be ascribed to photogenerated charge carriers separation and transferability were more, and recycle test confirms it has good stability. Moreover, a suitable photocatalytic degradation mechanism is also proposed.

Interfacial oxygen vacancy modulated ZIF-8-derived ZnO/CuS for the photocatalytic degradation of antibiotic and organic pollutants: DFT calculation and degradation pathways

Fabricating oxygen vacancies (Vo) is an effective approach to enhance photocatalytic performance, but its effect on the interfacial charge transfer pathway remains unelucidated to date. In this study, we used the simple aqueous solution method to create an oxygen-defected ZIF-8-derived CuS/ZnO (CZ) heterostructure, and various characterization techniques were used to investigate the prepared catalysts. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) were used to determine the surface defects caused by the CuS nanoparticles in the ZnO matrix generated from ZIF-8. The optimized CuS/ZnO (CZ-2) catalyst exhibited efficient photocatalytic performance by effectively increasing the charge separation rate of the photogenerated electrons. The photocatalytic performances of methylene orange (MO) and ciprofloxacin (CIP) using the CZ heterostructure were 99.76 % and 94.59 %, respectively, with the corresponding rate constants of 0.0695 and 0.0312 min−1 at 40 min. The electron spin resonance and scavenger tests have established that •O2− is the primary oxidative radical species involved in photocatalytic activity. In addition, the density functional theory calculations were performed to determine the degradation mechanism of CIP, and the possible pathways of CIP degradation were investigated using liquid chromatography–mass spectroscopy. This study provides new insights into the development of metal–organic frameworks and metal sulfide-based heterostructures for environmental degradation applications.

Low temperature in situ fabrication of NiFe2O4/tetragonal-BiVO4/Bi2MoO6 ternary heterostructure: A conjugated step-scheme multijunction photocatalyst with synergistic charge migration for antibiotic photodegradation and H2 generation

Rational design of novel conjugated step-scheme (S-scheme) multijunction heterostructure with synergistic charge channelization, superior light harvesting efficiency and strong redox ability is a pioneering approach to mimic natural photosynthesis process. Herein, a mild cetyltrimethyl ammoniumbromide (CTAB) assisted one pot reflux synthesis route is designed for in situ integration of metal organic framework (MOF)-derived NiFe2O4 with tetragonal-BiVO4 (t-BiVO4) and γ-Bi2MoO6 to prepare NiFe2O4/t-BiVO4/Bi2MoO6 (NFO/BVO/BMO) ternary composites. Morphologically, fine dispersion of NiFe2O4 (NFO) quantum dots over γ-Bi2MoO6 (BMO) and t-BiVO4 (BVO) nanoplates yielded three types of microscopic heterojunctions among BMO-BVO, BVO-NFO and BMO-NFO phases. The ternary composites displayed important physicochemical attributes including high surface area, strong optical absorption, superior charge mobility and higher excited state lifetime which accounted for its improved photocatalytic activity towards ciprofloxacin degradation (>99% in 90 min) and H2 evolution (1.11 mmolh-1g−1, photon conversion efficiency 18.5%). Kinetics study revealed 12–55 fold higher ciprofloxacin photodegradation activity and 31–41 times higher H2 evolution rate for the ternary composite in comparison to the pure semiconductors. A conjugated S-scheme charge transfer mechanism has been deduced from comprehensive band position analysis and radical trapping study to explain the enhanced photocatalytic activity. This work for the first time demonstrated the rational construction of conjugated S-scheme heterostructures with potential application in water remediation and green H2 production.

Degradation of the antibiotic ciprofloxacin in urine by electrochemical oxidation with a DSA anode

Ciprofloxacin (CIP) is a commonly prescribed fluoroquinolone antibiotic that, even after uptake, remains unmetabolized to a significant extent—over 70%. Unmetabolized CIP is excreted through both urine and feces. This persistent compound manages to evade removal in municipal wastewater facilities, leading to its substantial accumulation in aquatic environments. This accumulation raises concerns about potential risks to the health of various living organisms. Herein, we present a study on the remediation of CIP in synthetic urine by electrochemical oxidation in an undivided cell with a DSA (Ti/IrO2) anode and a stainless-steel cathode. Physisorbed hydroxyl radical formed at the anode surface from water discharge and free chlorine generated from Cl− oxidation were the main oxidizing agents. The effect of pH and current density (j) on CIP degradation was examined, and its total removal was easily achieved at pH ≥ 7.0 and j ≥ 60 mA cm−2 due to the action of free chlorine. The CIP decay always followed a pseudo-first-order kinetics. The components of the synthetic urine were also oxidized. The main nitrogenated species released was NH3. A very small concentration of free chlorine was quantified at the end of the treatment, thus demonstrating the good performance of electrochemical oxidation and its effectiveness to destroy all the organic pollutants. The present study demonstrates the simultaneous oxidation of the organic components of urine during CIP degradation, thus showing a unique perspective for its electrochemical oxidation that enhances the environmental remediation strategies.

Hydroxyl and sulfate radical-based degradation of ciprofloxacin using UV-C and/or Fe2+-catalyzed peroxymonosulfate: Effects of process parameters and toxicity evaluation

Ciprofloxacin (CIP) is a valuable antibiotic and discharged in huge quantities in aquatic environment. Different •OH and SO4•−-based advanced oxidation technologies (AOTs), e.g., Fe2+/PMS, UV-C/PMS, and UV-C/Fe2+/PMS are developed for treatment of CIP. The removal of CIP by Fe2+/PMS, UV-C/PMS and UV-C/Fe2+/PMS was 63, 77, and 87 %, respectively, under identical conditions which showed better performance of UV-C/Fe2+/PMS. The UV-C/Fe2+/PMS also caused high removal of total organic carbon of CIP. This high performance of UV-C/Fe2+/PMS-based AOTs possibly looked due to dual activation of PMS by UV-C and Fe2+. The removal of CIP by the three AOTs was found due to •OH and SO4•− and the later showed high reactivities with CIP, i.e., 2.45 × 109 and 2.35 × 109 M−1 s−1, respectively. The study of factors affecting the reactivities and/or yield of •OH and SO4•− diminished CIP degradation efficiency. The change in pH of solution and temperature and doses of Fe2+, PMS, and CIP exhibited significant impacts on the removal of CIP. The addition of inorganic ions showed strong inhibiting effects of NO2–, CO32–, and HCO3– while Cu2+ showed facilitating role. Analysis of degradation of CIP by GC–MS was used to develop proposed pathways. Acute and chronic toxicities of CIP and its products were measured by ECOSAR program and showed the resulting products to be non-toxic.

Efficient degradation of ciprofloxacin by a flower-spherical Bi2MoO6/BiOCl Z-type heterojunction photocatalyst enriched with oxygen vacancies

Ciprofloxacin (CIP) is difficult to degrade naturally, for example by microorganisms, and will persist in water bodies for a long period of time, seriously jeopardizing the ecological environment and human health. Photocatalysis has high practical application value as a green and efficient technology. However, the photogenerated electrons and holes of the photocatalysts are prone to complexation, which limits the degradation efficiency of photocatalysis. Therefore, in this work, spherical Bi2MoO6/BiOCl (OVs-BMO/BOC) Z-type heterojunction photocatalysts enriched with oxygen vacancies (OVs) were successfully synthesized by a hydrothermal-calcination method. A series of characterizations showed that the OVs-BMO/BOC photocatalysts could perform Z-type charge transfer, which increased the visible light response range and improved the separation efficiency of photogenerated electrons and holes, thus improving the degradation efficiency of CIP. Under visible light, the removal efficiency of OVs-BMO/BOC composites for CIP could reach 97.40% at 120 min. It has a quasi-primary rate constant of 0.03008, which is 4.1, 3.48, and 2.19 times higher than that of monomeric BOC, BMO, and BMO/BOC, respectively. Meanwhile, the good stability of OVs-BMO/BOC was verified, and its degradation efficiency could still reach 87.80% after four cycles. Finally, electron spin resonance analysis and trapping experiments were carried out, which demonstrated that a large number of OVs were produced by the BMO/BOC composite photocatalyst generated by calcination, and also identified that the OVs-BMO/BOC produced active substances (•OH, h+, and •O2−), which revealed the mechanism of degradation of CIP by the OVs-BMO/BOC. Our study provides a new way of thinking to achieve efficient elimination of antibiotics from wastewater.

Epsilon-MnO2 simply prepared by redox precipitation as an efficient catalyst for ciprofloxacin degradation by activating peroxymonosulfate.

Four kinds of manganese oxides were successfully prepared by hydrothermal and redox precipitation methods, and the obtained oxides were used for CIP removal from water by activating PMS. The microstructure and surface properties of four oxides were systematically characterized. The results showed that ε-MnO2 prepared by the redox precipitation method had large surface area, low crystallinity, high surface Mn(III)/Mn(Ⅳ) ratio and the highest activation efficiency for PMS, that is, when the concentration of PMS was 0.6 g/L, 0.2 g/L ε-MnO2 could degrade 93% of CIP within 30 min. Multiple active oxygen species, such as sulfate radical, hydroxyl radical and singlet oxygen, were found in CIP degradation, among which sulfate radical was the most important one. The degradation reaction mainly occurred on the surface of the catalyst, and the surface hydroxyl group played an important role in the degradation. The catalyst could be regenerated in situ through the redox reaction between Mn4+ and Mn3+. The ε-MnO2 had the advantages of simple preparation, good stability and excellent performance, which provided the potential for developing new green antibiotic removal technology.

Nanotubes/nanorods-like structures of La-doped ZnO for degradation of Methylene Blue and Ciprofloxacin

In this study, nanotubes/nanorods-like structures of Zn0.97La0.03O compound were synthesized at different pH values (pH = 8, 9, 10, 11, and 12), and the photocatalytic response for Methylene Blue (MB) dye and Ciprofloxacin (CIP) drug were investigated. It was verified that the pH variation directly impacts the ZnO crystal structure, morphology, optical and photocatalytic properties. The basic and alkaline pH values cause a decrease in the crystallite size and these differences may have contributed to the band gap energy values variations. Oxygen vacancy defects (VO, VO+, and VO++) were abundant in the La-doped ZnO samples, which also demonstrated to be formed from mesopores, as seen in N2 adsorption/desorption results. The photocatalytic response of the materials was verified in MB and CIP solutions under UV irradiation conditions. The sample synthesized at pH 9 (ZL9) demonstrated greater capacity to remove MB (91.45 %) and CIP (87.6 %) in typical pseudo-first-order kinetics. Using different inhibitors, it was observed that the •OH radicals were the species involved in the photocatalysis of pollutants for the ZL9 sample. In addition, this material demonstrated a satisfactory ability to remove pollutants even after three consecutive uses. This study demonstrates that pH is an important parameter to consider in the synthesis process of ZnO nanostructures, directly influencing the structural, optical, and morphological properties and the degradation of highly dangerous dyes and drugs.

Dual function of magnetic field in enhancing antibiotic wastewater treatment by an integrated photocatalysis and fluidized bed biofilm reactor (FBBR)

The integrated photocatalysis and fluidized bed biofilm reactor (FBBR) is an attractive wastewater treatment technique for managing wastewater containing antibiotics. However, the fast recombination of photoinduced charge and low microbial activity limit the degradation and mineralization efficiency for antibiotics. To address this, we attempt to introduce magnetic field (MF) to the integrated system with B-doped Bi3O4Cl as the photocatalysts to effectively improve removal and mineralization of ciprofloxacin (CIP). As a consequence, the degradation rate reaches 96% after 40 d in integrated system with MF. The biofilm inside the integrated system with MF carrier can mineralize the photocatalytic products, thereby increasing the total organic carbon (TOC) degradation rate by more than 32%. The electrochemical experiment indicates the Lorentz force generated by MF can accelerate charge separation, increasing the electron concentration. Simultaneously, the increased amounts of electrons lead to the generation of more ·OH and ·O2−. MF addition also results in increased biomass, increased biological respiratory activity, microbial community evolution and accelerated microbial metabolism, enabling more members to biodegrade photocatalytic intermediates. Therefore, applied MF is an efficient method to enhance CIP degradation and mineralization by the integrated system.

Degradation of Ciprofloxacin by CuNiFe LDHs/BiO2-x Heterojunction-activated Peroxymonosulfate Under Visible Light Irradiation

Herein, a CuNiFe LDHs/BiO2-x composite photocatalyst was successfully synthesized using a hydrothermal method and applied to activate peroxymonosulfate to degrade ciprofloxacin under visible light irradiation. Owing to the synergistic effect of photocatalysis and PMS activation, a high removal efficiency of CIP up to 88.3% was achieved. The prepared photocatalysts were characterized using XRD, FT-IR, SEM, XPS, UV-Vis DRS, and other methods. The optimal loading amount of CuNiFe LDHs was determined, and the effects of PMS dosage, initial pH value, and inorganic anions (Cl-, CO32-, and NO3-) on the degradation were investigated. Electron paramagnetic resonance and free radical trapping experiments demonstrated that·OH and h+ were the main active species for degrading CIP, and the possible degradation mechanism of the system was proposed.

Bi-metal-organic framework-derived S-scheme InP/CuO-C heterostructure for robust photocatalytic degradation of ciprofloxacin in a microfluidic photoreactor

The presence of antibiotics in the environment raises significant environmental concerns due to their adverse impact on organisms and the potential transmission of drug-resistant genes. Heterostructure photocatalysts have emerged as a promising remedy for this issue. This study introduces an innovative approach that employs an In/Cu-organic framework (bimetallic-MOF) as a sacrificial precursor for crafting a carbon-supported InP/CuO heterostructure with adjustable band-matching properties. Through comprehensive analyses encompassing structural, morphological, optical, electrochemical, and density functional theory calculations, compelling evidence is presented for the cubic carbon layer housing zinc-blende InP and monoclinic CuO. Furthermore, the existence of an S-scheme charges transfer pathway between InP and CuO is strongly substantiated, significantly enhancing spatial charge separation. The engineered InP/CuO S-scheme nanoheterostructure exhibits exceptional performance and stability under visible light exposure within a custom-designed spiral microfluidic photoreactor (SMPR), achieving an impressive 81.70% degradation of ciprofloxacin – a commonly found antibiotic in wastewater – in just 15 min. The findings from photoelectrochemical and spectroscopic analyses reveal that the InP/CuO S-scheme heterostructure, derived from the bi-MOF, in conjunction with the SMPR, not only exhibits a robust response to visible light, improved carrier mobility, and effective charge separation and transfer, but also enhances mass and photon transfer. Within the S-scheme heterostructure, the process of charge transfer centers on the creation of reactive oxygen species, specifically OH and O2–, on InP and CuO surfaces, correspondingly. These species function as oxidation and reduction photocatalysts, respectively, exerting a pivotal influence in augmenting the overall performance. The findings make substantial contributions towards creating effective and sustainable solutions for mitigating environmental contamination, emphasizing the crucial role of advanced material design and microfluidic reactor engineering in the realm of photocatalysis.

Improving hydrodynamic cavitation using newer surface-coated cavitation reactors

Surface-coated cavitation devices, vortex diode (SCVD) have been reported for the first time for enhancing efficiency of hydrodynamic cavitation (HC). Two surface-coated cavitation reactors using coating of copper and nickel (∼50 µm) were evaluated, also comparing results with conventional reactor vortex diode. The proof of concept is successfully demonstrated for complete degradation of two model organic pollutants, antibiotics- cephalexin (CFX) and ciprofloxacin (CIP). The surface-coated reactors provide dual activity, and the catalytic effect is highly pronounced with process intensification using H2O2 and/ or pH alternations. Integration of SCVD, pH and H2O2 was the most effective strategy. Complete degradation of the antibiotics was achieved within minutes with H2O2 (∼1000 molar ratio) for both Cu and Ni- surface-coated cavitation reactors compared to lower degradation of ∼19% for CFX and ∼37% for CIP using only HC. An excellent enhancement of over 300% for CFX degradation at pH 11 and ∼170% for CIP degradation at pH 4 was obtained. Huge enhancements in per-pass degradation and cavitational yields (up to 400 times) clearly highlight the utility of the surface-coated cavitation reactors in various applications and for cost-effectiveness.

Diurnal-independent, visible-light-storing of Ag2O@SrAl2O4:Eu2+,Dy3+ for the round-the-clock decomposition of ciprofloxacin

A round-the-clock photocatalyst that can efficiently separate charge carriers will break through the practical application of photocatalytic-based advanced oxidation processes (PC-AOPs) in wastewater treatment. In this work, an energy-storable p-n heterojunction Ag2O@SrAl2O4:Eu2+,Dy3+ (Ag2O@SAED) was successfully prepared to achieve round-the-clock photocatalytic degradation of ciprofloxacin (CIP). Ag2O@SAED can efficiently degrade ∼ 80 % of CIP (with ∼ 56 % mineralization) under low power consumption of 12 W LED visible light source radiation for 2 h. In addition, surprisingly, Ag2O@SAED also shows certain energy storage properties, so that it can effectively reduce the energy consumption of the treatment process compared with conventional photocatalytic processes. Non-radical singlet oxygen (1O2) is the main reactive species, which is produced mainly from intermediate superoxide radicals (·O2−). Moreover, the site of CIP attacked by 1O2 was tentatively confirmed by Fukui index based on density functional theory (DFT) calculations. The activities of round-the-clock degradation of CIP in different water matrices were examined. The degradation efficiency in tap water, Yangtze River and wastewater plant effluent were 61.88 %, 57.61 % and 55.87 %, respectively. The synergistic effect of p-n heterojunctions is effective in degrading CIP during daytime, and the light released from SAED activates the activity of Ag2O to degrade CIP at night. This study contributes to further understanding the principles and mechanisms of round-the-clock photocatalysts for degradation of organic pollutants and provides directions for the practical application of photocatalytic technology.