Tetracycline Degradation Efficiency Research Articles

Unlocking the superior flexibility and enhanced catalytic oxidation performance of CoTiO3 nanofibrous membranes through zirconium doping

The development of continuous CoTiO3 (CTO) fibers with prominent catalytic oxidation activity, tunable fibrous structures, and improved recyclability is appealing for application in efficient organic wastewater treatment; however, inescapable flaws remain, such as their inherent brittleness and adverse operability. Herein, a facile and effective strategy is proposed for the fabrication of flexible and mechanically robust CTO nanofibrous membranes through a combination of element doping and sol–gel-assisted electrospinning. Compared with pristine CTO fibers, the resulting zirconium-doped CoTiO3 (ZCTO) nanofibrous membranes displayed remarkably enhanced flexibility and tensile mechanics, which were attributed to their lower crystallinity, smaller grain size, and fewer fiber surface defects. The developed ZCTO fibrous membrane demonstrated exceptional resistance to bending fatigue, retaining a polymer-like bending rigidity of approximately 25 mN even after undergoing 200 reciprocating bending cycles. Furthermore, the incorporation of zirconium into CTO clearly had an advantageous effect on the formation of oxygen vacancies, thereby enhancing the surface adsorption of peroxymonosulfate (PMS), accelerating the electron transfer process, and weakening the peroxy bonds. The tetracycline degradation efficiency of the ZCTO fibers remained at 81.4% within 10 min after 5 continuous cycles. Benefiting from their robust mechanical properties and excellent catalytic activity, the fabricated membranes demonstrated outstanding dynamic catalytic performance under gravity-driven conditions. More importantly, the reported strategy might be adopted and extended to develop a wide range of ceramic fibers with enhanced flexibility and mechanics for catalytic oxidation.

Bronze TiO2-MXene heterostructures for dramatic enhancement of photocatalytic degradation of tetracycline under visible light

Although TiO2 nanomaterials have been widely used for the photocatalytic degradation of antibiotic pollutants in aqueous environments under ultraviolet (UV)-light irradiation, their photocatalytic performances are still unsatisfactory under visible light because of the large band gap. Herein, the bronze TiO2-MXene (TiO2(B)-MXene) heterostructures are successfully prepared and serve as photocatalysts to degrade the tetracycline (TC) pollutants under visible light for the first time. As a result, the heterostructure photocatalysts (20 mg) realize almost ∼ 92 % degradation efficiency of TC (20 mg L-1, 100 mL) in 40 min under the irradiation of Xe lamp (300 W), attributing to the synergistic effect of MXene nanosheets and TiO2(B) nano-flowers.

Influence of metal ions (Me: Fe, Cu, Co, Ni, Mn, Cr) on direct Z-scheme photocatalysts CN/Me-BTC on the degradation efficiency of tetracycline in water environment

BackgroundThe World Health Organization (WHO) reports that antibiotic resistance contributes to approximately 700,000 deaths yearly, with estimate suggesting a rise to 10 million deaths over the next 35 years. MethodsIn this study, direct Z-scheme heterojunction photocatalysts CN/Me-BTC (CN: graphite carbon nitride, Me: metal ions, BTC: benzene-1,3,5-tricarboxylic acid) were successfully synthesized using a hydrothermal combined microwave method, eliminating the need for toxic solvents and featuring a short crystallization time and low reaction temperature. Significant findingsThe study also explores the influence of various metal ions (Fe, Ni, Co, Mn, Cr, and Cu) on the morphological, physicochemical properties, and photocatalytic efficiency of tetracycline (TC) degradation. The CN/Me-BTC photocatalysts exhibit remarkable characteristics, including high visible light absorption, high surface area, low recombination rate between electrons and holes, and fast charge transfer ability.Among the synthesized photocatalysts, CN/FeBTC stands out with the highest efficiency in TC degradation (97.18 %) and degradation rate (decay constant k = 0.0197 min−1), surpassing CN by four times. The study comprehensively investigates factors influencing the TC degradation process, including catalyst mass, pH, antibiotic concentration, participating radicals, anions, and water sources. The mechanism of the photocatalytic process is elucidated based on radical quenching experiments and electrochemical properties.

Efficient degradation of tetracycline by activated peroxymonosulfate with high permeate flux FeTiOx reactive ceramic membrane: Membrane preparation, real wastewater application, and mechanism insight

Antibiotic residue in wastewater is one of the most worrying environmental pollution problems. In this study, innovative bimetallic nanocatalysts of FeTiOx were prepared. Benefiting from the synergistic effect between Ti and Fe, FeTiOx exhibited an excellent performance in activating peroxymonosulfate (PMS) for tetracycline (TC) degradation. Within 60 min, the TC treatment efficiency can reach 96 %. Mechanism study confirmed that the non-free radical pathway (1O2) and free radical pathway (O2−, OH, SO4−) co-participated during the TC treatment process. To further improve the separation function and efficiency, FeTiOx nanocatalyst was loaded on the ceramic membrane (CM) by a facile spraying method and a self-designed experimental device was constructed, which can be used to degrade TC with large volume. In the designed device, 2 L 40 mg/L TC wastewater can be degraded at one time with an efficiency of 85 % and a permeate flux of 1011.66 kg/m2·h when the transmembrane pressure (TMP) was 20 kPa. Finally, real pharmaceutical wastewater was treated and found that the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3−N) and total organic carbon (TOC) were 70.3 %, 62.85 % and 32.8 %, respectively. The study provides a new strategy for treating wastewater pollutants by combining CM technology with advanced oxidation processes (AOPs).

Enhancement of Peroxydisulfate Activation for Complete Degradation of Refractory Tetracycline by 3D Self-Supported MoS2/MXene Nanocomplex.

Antibiotic abuse, particularly the excessive use of tetracycline (TC), a drug with significant environmental risk, has gravely harmed natural water bodies and even posed danger to human health. In this study, a three-dimensional self-supported MoS2/MXene nanohybrid with an expanded layer spacing was synthesized via a facile one-step hydrothermal method and used to activate peroxydisulfate (PDS) for the complete degradation of TC. The results showed that a stronger •OH signal was detected in the aqueous solution containing MoS2/MXene, demonstrating a superior PDS activation effect compared to MoS2 or Ti3C2TX MXene alone. Under the conditions of a catalyst dosage of 0.4 g/L, a PDS concentration of 0.4 mM, and pH = 5.0, the MoS2/MXene/PDS system was able to fully eliminate TC within one hour, which was probably due to the presence of several reactive oxygen species (ROS) (•OH, SO4•-, and O2•-) in the system. The high TC degradation efficiency could be maintained under the influence of various interfering ions and after five cycles, indicating that MoS2/MXene has good anti-interference and reusability performance. Furthermore, the possible degradation pathways were proposed by combining liquid chromatography-mass spectrometry (LC-MS) data and other findings, and the mechanism of the MoS2/MXene/PDS system on the degradation process of TC was elucidated by deducing the possible mechanism of ROS generation in the reaction process. All of these findings suggest that the MoS2/MXene composite catalyst has strong antibiotic removal capabilities with a wide range of application prospects.

BaTi0.85Zr0.15O3/MOF-5 nanocomposite: Synthesis, characterization and photocatalytic activity toward tetracycline

It has been proposed that oriented anchoring strategies can be used to organize BaTi0.85Zr0.15O3 (BTZ) quantum dots (QD) with MOF-5 to provide highly efficient catalytic degradation of tetracycline (TC). This study presents the preparation of [Zn4O (BDC)3] (BDC = benzene-1,4dicarboxylate) metal–organic framework-5 (MOF-5)/BTZ nanocomposites by a facile one-pot solvent-thermal precipitation method. The as-synthesized samples were identified by XRD, TG-DTG, UV–VIS DRS, FESEM, FTIR, BET, TEM, PL, and EDX characterization techniques. The photocatalytic ability of nanocomposite BTZ (30 %wt)/MOF-5 was particularly impressive among the binary photocatalysts. In a 10 ppm solution of TC, BTZ (30 wt%)/MOF-5 demonstrated superior photodegradation activity, with 95 % degradation efficiency of TC determined by HPLC. The best response was achieved at pH 11 with catalyst dosages of 0.2 g/L, irradiation time of 150 min, and CTC of 10 ppm. An internal electric field was suggested to mediate the direct Z-scheme charge transfer mechanism between BTZ and MOF-5. The improvement was achieved by fabricating BTZ and MOF-5 in an indirect Z-scheme heterojunction system. Photogenerated electron-hole separation can be accelerated by BTZ/MOF-5 with improved redox capabilities. Overall, taking advantage of an enhanced redox capacity under ultraviolet (UV) light irradiation, this study demonstrates how to promote efficient antibiotic degradation using MOF-based nanocomposites. Moreover, photodegradation kinetics were studied using the Hinshelwood formula, giving 0.0113 min−1 (slope) and 61.32 min as t1/2. In the COD experiment, mineralized TC molecules had y = -0.0144 + 0.0444x, r2 = 0.9942, and k = 0.0144 min−1 (t1/2 = 48.12 min).

Cobalt and chlorine co-doped Bi5O7I catalysts for LED-induced photocatalytic or PMS-activation antibiotics degradation

Multifunctional semiconductor catalysts can meet the urgent needs for the removal of antibiotic pollutants in water. Bifunctional catalysts, cobalt and chlorine co-doped Bi5O7I (signed as Co-BIC) catalysts, were purposefully designed through a two-step aqueous strategy. The preformed Bi5O7I precursor provided one-dimensional structure and Bi-rich character for the construction of Co-BIC catalysts. Co and Cl co-doping in Bi5O7I crystals can form a doping energy level and improve the internal electric field, which led to enlarged visible-light absorption and charge separation efficiency during the photocatalytic reaction process. These advantages made Co-BIC crystals exhibit good photocatalytic activities for the removal of antibiotic levofloxacin (LEV), ciprofloxacin (CIP) and tetracycline (TC) under visible LED (100 W) light irradiation. The degradation efficiency of LEV, CIP and TC over the typical Co-BIC-60 catalyst can reach more than 80 % under 60 min of LED irradiation. In the system of Co-BIC activated peroxymonosulfate (PMS), ∼ 90 % of LEV, CIP and TC degraded within 20 min over 20 mg of Co-BIC-60 catalyst. The mechanism of photocatalytic degradation and PMS oxidation degradation over Co-BIC catalysts was proposed on band structures of Co-BIC catalysts and the active species in the capture experiments. This work could provide new ideas for the preparation of bismuth oxyhalide catalysts coupled with transition metal elements.

Facile synthesis of nano CeO2/sepiolite composite as visible-light-driven photocatalyst for rapid tetracycline removal

A novel CeO2/sepiolite (CeO2/SEP) composite with sepiolite as the support of CeO2 was successfully prepared using a simple ammonia precipitation method for the photocatalytic degradation of tetracycline (TC) by loading CeO2 nanoparticles on sepiolite. The analytical results showed that CeO2/SEP had good crystallization, and CeO2 nanoparticles were deposited on the surface of fibrous sepiolite. The composite photocatalyst with 50 % CeO2 loading presented the highest tetracycline degradation efficiency (92.7 %), and the reaction rate constant was 4.88 times greater than that of pure CeO2. In addition, quenching experiments showed that the main reactive active species included photogenerated holes (h+) and superoxide radical anions(O2·-).Furthermore, the enhanced photodegradation mechanisms and the possible degradation pathways of TC were also systematically discussed. The investigating results show that the enhanced photocatalytic performance was mainly due to the uniform attachment of CeO2 with smaller particle size on the surface of sepiolite, which increased the specific surface area of the photocatalyst and promoted the redox cycle of Ce3+/Ce4+ to generate more reactive free radicals. It can be concluded that this study offers a new potential option for efficient photodegradation of antibiotics in wastewater based on the visible-light-driven mineral based photocatalyst.

Synthesis of near-infrared-activated YF3:Yb3+, Tm3+/Bi2MoO6 upconversion photocatalytic materials for the photocatalytic degradation of antibiotics based on fluorescence resonance energy transfer

Photocatalytic degradation of pollutants, an ecofriendly technology, is widely used for environmental remediation. However, the design and synthesis of photocatalytic materials for near-infrared light photocatalysis are challenging. In this study, an upconversion photocatalyst with fluorescence resonance energy transfer (FRET), YF3:Yb3+, Tm3+/Bi2MoO6 (YFYT/BMO), was developed and synthesised based on rare-earth upconversion luminescence. YFYT converted near-infrared (NIR) light into blue–violet light via upconversion. The rapid decay of the fluorescence lifetime of YFYT/BMO at 478 nm (Tm3+:1G4-3H6) verified that FRET efficiently occurred between YFYT and BMO. The degradation rate of tetracycline by YFYT/BMO was 2.6 times higher than that by BMO under NIR light. A great enhancement of 42.1 % on the tetracycline degradation efficiency was achieved in YFYT/BMO compared with pure BMO within 90 min of visible-NIR irradiation. This study provides a basis for developing and designing rare-earth upconversion photocatalytic materials that can achieve excellent photocatalytic degradation of antibiotics using NIR light for environmental remediation.

Enhanced electron transfer using NiCo2O4@C hollow nanocages with an electron-shuttle effect for efficient tetracycline degradation

Spinel oxides are recognized as promising Fenton-like catalysts for the degradation of antibiotics. However, the catalytic performance is restrained by the poor electron transfer rate (ETR). Herein, hollow NiCo2O4@C nanocages are rationally designed and prepared to accelerate ETR in peroxymonosulfate (PMS) activation for tetracycline (TC) degradation. Enhanced ETR of the NiCo2O4@C/PMS system is due to three aspects: (1) The hollow nanocage facilitates the diffusion and adsorption of TC, improving the ion transfer at a macroscopic level; (2) Electron reconfiguration in octahedral sites of NiCo2O4 increases the ratio of Co2+, resulting in highly efficient PMS activation; (3) In-situ generated carbon acts as “electron shuttles”, improving the electrical conductivity of catalysts at a microscopic level. As a result, the NiCo2O4@C demonstrates rapid ETR, leading to a high-efficiency activation of PMS. The NiCo2O4@C/PMS system exhibits exceptional TC degradation efficiency and reusability. Non-radical pathway, including 1O2 and direct electron transfer, dominates the system. This work offers a feasible strategy for enhancing electron transfer in the Fenton-like system.

A novel BiOBr/rGO photocatalysts for degradation of organic and antibiotic pollutants under visible light irradiation: Tetracycline degradation pathways, kinetics, and mechanism insight

In this study, the BiOBr/rGO nanocomposite photocatalysts are fabricated by a facile solvothermal method. The BiOBr growth on reduced graphene oxide (rGO) sheet could improve BiOBr's photocatalytic activity by increasing its adsorption ability, surface area, and charge carriers' separation efficiency. The prepared nanocomposites were characterized by XRD, Raman, FESEM, EDS, XPS, and UV-visible DRS. The BiOBr/rGO (BRG) nanocomposites showed improved photocatalytic activity for the photodegradation of Rhodamine B (RhB) dye and Tetracycline (TC) under visible light irradiation. Rhodamine B and tetracycline degradation efficiency were about 96% and 73% within 120 mins under visible light irradiation. The PL analysis indicates that BiOBr/rGO nanocomposite exhibited maximum separation efficiency of photoinduced charge carriers. The trapping test confirmed that O2- and h+ are significant active photodegradation species. The GC-MS spectra detected the two plausible transformation routes of tetracycline degradation. The current work presented a low-cost and facile approach for fabricating Bi-based composites.

The construction of Z-scheme heterojunction ZnIn2S4@CuO with enhanced charge transfer capability and its mechanism study for the visible light degradation of tetracycline

In this study, copper oxide (CuO) was prepared by the microwave-assisted hydrothermal technique subsequently, CuO was grown in situ onto different rare metal compounds to prepare Z-scheme heterojunctions to improve the degradation efficiency of tetracycline (TC) in water environments. Various characterization proved the successful synthesis of all composite materials, and the formation of tight heterojunction interfaces, among which, the core–shell structure ZnIn2S4@CuO exhibited excellent photocatalytic degradation capability. Research results indicated that the degradation efficiency of ZnIn2S4@CuO for TC (50 mg/L) in the water environment reached 95.8 %, and the degradation rate is 2.41 times and 12.93 times that of CuO and ZnIn2S4 alone, respectively, the reason is because of the introduction of ZnIn2S4, Z-scheme heterojunction structures and internal electric field (IEF) is constructed and formed to extend the visible light response range of photocatalysts to improve electron-hole separation efficiency, and enhance charge transfer. In addition, ZnIn2S4@CuO-2 exhibited good stability and reproducibility, with no significant loss of activity after five cycles. Finally, the precise locations of free radical attack on TC were investigated by the combined use of high-resolution mass spectrometry (HR-MC) and frontier electron densities (FEDs), and a reasonable degradation pathway was provided. The results of this research provide a new and viable approach to overcome the limitations of conventional photocatalytic materials in terms of limited visible light absorption range and fast carrier recombination rates, which offers promising prospects for a wide range of applications in the field of wastewater purification.

Hollow Cu2-xS@NiFe Layered Double Hydroxide Core-Shell S-Scheme Heterojunctions with Broad-Spectrum Response and Enhanced Photothermal-Photocatalytic Performance.

Designing a reasonable heterojunction is an efficient path to improve the separation of photogenerated charges and enhance photocatalytic activity. In this study, Cu2-xS@NiFe-LDH hollow nanoboxes with core-shell structure are successfully prepared. The results show that Cu2-xS@NiFe-LDH with broad-spectrum response has good photothermal and photocatalytic activity, and the photocatalytic activity and stability of the catalyst are enhanced by the establishment of unique hollow structure and core-shell heterojunction structure. Transient PL spectra (TRPL) indicates that constructing Cu2-xS@NiFe-LDH heterojunction can prolong carrier lifetime obviously. Cu2-xS@NiFe-LDH shows a high photocatalytic hydrogen production efficiency (5176.93µmolh-1g-1), and tetracycline degradation efficiency (98.3%), and its hydrogen production rate is ≈10-12 times that of pure Cu2-xS and NiFe-LDH. In situ X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) provide proofs of the S-scheme electron transfer path. The S-scheme heterojunction achieves high spatial charge separation and exhibits strong photoredox ability, thus improving the photocatalytic performance.

Boron nitride nanosheets modified BiOBr photocatalysts for promoting photocatalytic removal of tetracycline under visible light irradiation

A series of BN/BiOBr heterojunctions was constructed using in situ hydrothermal-precipitation method and was employed to remove the tetracycline molecules in aqueous solution. The rate of photocatalytic degradation efficiency of tetracycline by 0.05BN/BiOBr was ensured to be more excellent than that by BiOBr. The heterojunciton fabricated between BN and BiOBr enforced an internal electrons transfer from BiOBr to BN, which remarkably inhibited charge recombination. The major reactive species involved in the photocatalysis system were found to be hydroxyl radicals (•OH) and photo-holes (h+), which was verified by the scavenger tests. 0.05-BN/BiOBr heterojunctions showed remarkable reusability and still could degrade 89.25% of tetracycline after four consecutive cycles. According to the characterization and experimental results, a plausible enhanced photocatalytic mechanism was put forward. This work provided the guidance for rational designing heterojunctions with remarkable performance towards antibiotics elimination from wastewater.

Photocatalytic degradation of tetracycline using a novel WO3–ZnO/AC under visible light irradiation: Optimization of effective factors by RSM-CCD

Mitigating pharmaceutical pollution in the global environment is imperative, and tetracycline (TC) is a commonly utilized antibiotic in human and veterinary medicine. The persistent existence of TC highlights the necessity of establishing efficient measures to protect water systems and the environment from detrimental contaminants. Herein, a novel rhubarb seed waste-derived activated carbon-supported photocatalyst (WO3–ZnO/RUAC) was synthesized by combining wet impregnation and ultrasonic methods. The activated carbon (AC) was obtained from rhubarb seed waste for the first time via chemical activation. The function of AC as an electron acceptor and in separating electron-hole pairs was illuminated by characterization analyses that included XRD, FTIR, XPS, SEM, TEM, PL, EIS, TPC, and UV-DRS. Using the response surface methodology-central composite design (RSM-CCD) technique, the synthesis parameters of the composite were systematically optimized. Under ideal conditions, with a TC concentration of 33 mg. L−1, pH of 4.57, irradiation time of 108 min, and catalyst dose of 0.85 g. L−1, the highest degradation efficiency of TC by this composite, achieved 96.5%, and it was reusable for five cycles. Subsequently, trapping tests and electron spin resonance (ESR) analysis were conducted, elucidating that •OH and •O2− radicals played pivotal roles in the photocatalytic degradation of TC. This research offers valuable insights into utilizing the AC-based photocatalyst to degrade pharmaceutical micropollutants effectively.

Robust photoelectrocatalytic degradation of antibiotics by organic-inorganic PDISA/Bi2WO6 S-scheme heterojunction membrane

Ensuring the stability of the photoelectrode is paramount for optimal photoelectrocatalysis performance. In this investigation, a hybrid nanofiber film, incorporating the π-π conjugated self-assembly of perylene diimide monomers (PDISA) with Bi2WO6 (PDISA/Bi2WO6), was fabricated through the electrospinning process. Subsequently, this flexible electrospun film was pressed onto a Ni mesh to create a robust PDISA/Bi2WO6 electrode membrane. Results from photoelectrocatalytic studies reveal that the devised PDISA/Bi2WO6 photoanode significantly enhances the photoelectrocatalytic degradation efficiency of tetracycline (TC) and ciprofloxacin (CIP). Specifically, the apparent rate constants for the photoelectrocatalytic degradation of TC by 30%PDISA/Bi2WO6, compared to pristine PDISA and Bi2WO6, are elevated by 1.9 and 2.0 times, respectively. Moreover, the reaction rates of the photoelectrocatalytic (PEC) process surpass those of photocatalysis (PC) and electrocatalysis (EC) by 1.9 times and 8.0 times, respectively. Impressively, even after five cycles of PEC degradation of TC, the photoelectrode maintains 98.4% of its initial degradation rate, indicating its exceptional stability. These improvements in degradation efficiency and stability are attributed to the creation of the PDISA/Bi2WO6 S-scheme heterojunction membrane photoanode and the synergistic effects of photoelectrocatalysis.

Efficient removal of TC and CIP antibiotics by surface modified g-C3N4/CdS nanocomposite under sunlight irradiation

Aquatic environment organic pollutant removal is very essential for human health. Tetracycline (TC) and Ciprofloxacin (CIP) are most use antibiotics to treat the bacterial infections. These antibiotics are entering into the aquatic system through feces and urine of both humans and animals, thereby increasing the environmental toxicity. Consequently, it is crucial to treat the antibiotics residues from the aquatic environment. Photocatalysis method is considered as a promising way to effectively treat the contaminated aquatic environment. The g-C3N4/CdS was successfully synthesized through a simple hydrothermal method. Various characterization techniques were used to examine the physical and chemical characteristics of the synthesized materials. The g-C3N4/CdS nanocomposite has high surface area 76.12 m2/g, narrow band gap energy 2.26 eV, and less electron-hole recombination. The g-C3N4/CdS photocatalyst shows higher degradation efficiency of TC and CIP as 96.2 and 80% in 40 min under sunlight irradiation. In addition, the radical trapping experiment reveals that h+, •O2− and 1O2 are the key role for the degradation of TC and CIP over g-C3N4/CdS nanocomposite. Moreover, the intermediate by products of TC and CIP were also examined by using GC-MS. This work, facilitates that the construction of g-C3N4/CdS nanocomposite have high capable to remove the toxic substances from the contaminated water under direct sunlight irradiation.

Efficient peroxymonosulfate activation by nanoscale zerovalent iron for removal of sulfadiazine and sulfadiazine resistance bacteria: Sulfidated modification or not

Whether it’s necessary to extra chemical synthesis steps to modify nZVI in peroxymonosulfate (PMS) activation process are worth to further investigation. The 56 mg/L nZVI/153.65 mg/L PMS and 56 mg/L sulfidated nZVI (S-nZVI) (S/Fe molar ratio = 1:5)/153.65 mg/L PMS) processes could effectively attain 97.7% (with kobs of 3.7817 min−1) and 97.0% (with kobs of 3.4966 min−1) of the degradation of 20 mg/L sulfadiazine (SDZ) in 1 min, respectively. The nZVI/PMS system could quickly achieve 85.5% degradation of 20 mg/L SDZ in 1 min and effectively inactivate 99.99% of coexisting Pseudomonas. HLS-6 (5.81-log) in 30 min. Electron paramagnetic resonance tests and radical quenching experiments determined SO4•−, HO•, 1O2 and O2•− were responsible for SDZ degradation. The nZVI/PMS system could still achieve the satisfactory degradation efficiency of SDZ under the influence of humic acid (exceeded 96.1%), common anions (exceeded 67.3%), synthetic wastewater effluent (exceeded 90.7%) and real wastewater effluent (exceeded 78.7%). The high degradation efficiency of tetracycline (exceeded 98.9%) and five common disinfectants (exceeded 96.3%) confirmed the applicability of the two systems for pollutants removal. It’s no necessary to extra chemical synthesis steps to modify nZVI for PMS activation to remove both chemical and biological pollutants.

Amorphous FeOOH shell decorated Bi2O4 for the boosted photocatalytic degradation of tetracycline under visible irradiation

At present, the regulation of photocatalyst properties and highly efficient degradation of emerging contaminants are still challenging tasks. Herein, a novel core-shell composite catalyst Bi2O4 @FeOOH was fabricated by in situ depositing amorphous FeOOH nanoparticles on the outside surface of Bi2O4. A series of characterizations were conducted for the fabricated Bi2O4 @FeOOH. The photocatalytic activity of Bi2O4 @FeOOH was assessed via the degradation of tetracycline (TC) under visible irradiation. The formation of the amorphous FeOOH shell improves the visible-light harvesting capability, enlarges the specific surface area, and accelerates the transfer of the photo-induced electron. The synergistic effect of these positive factors enables the prepared Bi2O4 @FeOOH to exhibit a considerably reinforced activity and excellent stability for TC degradation. The degradation efficiency of TC on Bi2O4 @FeOOH is up to 84.2%, which is markedly higher than that over FeOOH (20.4%) and Bi2O4 (43.5%). After five reuses, the activity of Bi2O4 @FeOOH shows no obvious decrease. The degradation rate constant of TC by Bi2O4 @FeOOH is 0.01434 min−1, which is approximately 2.4 and 5.8 times those by Bi2O4 and FeOOH. This work affords a new strategy for the design of highly efficient photocatalysts that can be applied in the photocatalytic decomposition of emerging contaminants.

Effective degradation of tetracycline and real pharmaceutical wastewater using novel nanocomposites of biosynthesized ZnO and carbonized toner powder

In this study, novel nanohybrids of biosynthesized zinc oxide (ZnO) and magnetite-nanocarbon (Fe3O4–NC) obtained from the carbonization of toner powder waste were fabricated and investigated for persulfate (PS) activation for the efficient degradation of tetracycline (TCN). The chemical and physical properties of the synthesized catalysts were analyzed using advanced techniques. ZnO/Fe3O4–NC nanohybrid with mass ratio 1:2, respectively in the presence of PS showed the highest TCN removal efficiency compared to the individual components (ZnO and Fe3O4–NC) and other nanohybrids with mass ratios of 1:1 and 2:1. The results indicated that efficient degradation of TCN could be attained at pH 3–7. The optimum operating parameters were TCN concentration of 12.8 mg/L, PS concentration of 7 Mm, and catalyst dose of 0.55 g/L. The high stability of ZnO/Fe3O4–NC (1:2) nanocomposite was assured by the slight drop in TCN degradation percentage from 97.27% to 85.45% after five successive runs under the optimum conditions and the concentrations of leached iron and zinc into the solution were monitored. The quenching experiments explored that the prevailing reactive entities were sulfate radicals. Additionally, the degradation of TCN in various water matrices was investigated, and a degradation pathway was suggested. Further, degradation of real pharmaceutical waste was conducted showing that the removal efficiencies of TCN, total organic carbon (TOC), and chemical oxygen demand (COD) were 89.79, 80.65, and 78.64% after 2 h under the optimum conditions. The effectiveness of the proposed system (ZnO/Fe3O4–NC (1:2) @ PS) for the degradation of real samples compiled from industrial effluents as well as its inexpensiveness and green nature qualify this system for the full-scale application.