Synthesis and characterizations of FeNi 3 @SiO 2 @TiO 2 nanocomposite and its application in photo- catalytic degradation of tetracycline in simulated wastewater

Catalytic wet air oxidation removal of tetracycline by La2O3 immobilized on recycled polyethylene terephthalate using the response surface methodology

This study investigated the removal of tetracycline from the aqueous solutions by lanthanum oxide nanoparticles covered with polyethylene terephthalate (PET) using a low-cost and facile co-precipitation method, via catalytic wet air oxidation process (CWAO) by response surface methodology (RSM). XRD, FTIR, SEM, and EDX-map techniques have been employed to investigate the crystal structure, functional groups on the surface, morphologic characteristics, and elemental composition, respectively. Under optimum conditions (pH= 9, initial TC concentration= 20 mg L-1, nanocomposite dosage= 1.5 g L-1, pressure= 4 bar, temperature= 70 °C, and time= 90 min), TC removal efficiency by La2O3-PET was achieved at about 99.9%. The environmental parameters were assessed to determine tetracycline catalytic wet air oxidation degradation rate, which included cleaning gases, hydrogen peroxide, type of organic compounds, anions, radical scavenger and reusability. The ANOVA results indicated that the polynomial model proves that the model is entirely meaningful (F-value> 0.001 and P-value< 0.0001) and has high coefficient values of adjusted R2 (0.7404) and predicted R2 (0.5940). The findings indicated that the variables of time, pH, temperature, dosage, and TC concentration have the greatest role in removing tetracycline, respectively. However, pressure as a factor does not have a considerable influence on the performance of the system. In general, due to the presence of the role of additional anionics, the effectiveness of this method for removing tetracycline from drinking water was 82.76%. The catalyst indicated pleasing stability and recycling power during eight testing cycles. Further, the estimated electrical energy per order consumption (EEO) for the CWAO/La2O3-PET system was calculated as 5.31 kWh m-3 with an operational cost (OC) utilization of 1.78 USD kg-1 and it has been shown that this process is feasible and economically comparable to other CWAO processes. The breakdown intermediate products of tetracycline in the CWAO were examined using gas chromatography/mass spectrometry (GC-MS) analysis. The toxicity analyses for the removal of TC were carried out using Daphnia magna and the CWAO process achieved a remarkable decrease in the presence of La2O3-PET nanocomposite (LC50 and toxicity unit (TU) 48 h equal to 0.634 and 157.72 vol percent).

Using NaOH@Graphene oxide-Fe3O4 as a magnetic heterogeneous catalyst for ultrasonic transesterification; experimental and modelling

Burning fossil fuels causes toxic gas emissions to increase, therefore, scientists are trying to find alternative green fuels. One of the important alternative fuels is biodiesel. However, using eco-friendly primary materials is a main factor. Sustainable catalysts should have high performance, good activity, easy separation from reaction cells, and regenerability. In this study, to solve the mentioned problem NaOH@Graphene oxide-Fe3O4 as a magnetic catalyst was used for the first time to generate biodiesel from waste cooking oil. The crystal structure, functional groups, surface area and morphology of catalyst were studied by XRD, FTIR, BET, and FESEM techniques. The response surface methodology based central composite design (RSM-CCD) was used for biodiesel production via ultrasonic technique. The maximum biodiesel yield was 95.88% in the following operation: 10.52:1 molar ratio of methanol to oil, a catalyst weight of 3.76 wt%, a voltage of 49.58 kHz, and a time of 33.29 min. The physiochemical characterization of biodiesel was based to ASTM standard. The magnetic catalyst was high standstill to free fatty acid due to the five cycle's regeneration. The kinetic study results possess good agreement with first-order kinetics as well as the activation energy and Arrhenius constant are 49.2 kJ/min and 16.47 * 1010 min-1, respectively.

Insightful properties-performance study of Ti-Cu-O heterojunction sonochemically embedded in mesoporous silica matrix for efficient tetracycline adsorption and photodegradation: RSM and ANN-based modeling and optimization

This study aims to provide a comprehensive evaluation of the photocatalytic properties and performance of the Cu-Ti-O heterojunction sonochemically embedded in the mesoporous silica matrix. Various characterization analyses and adsorption/photodegradation experiments were performed to assess the potential of the sample for tetracycline (TC) removal. The characterization results indicated that sonication contributes to better dispersion of Ti-Cu-O species, resulting in more uniform particle sizes, stronger semiconductors-silica interaction, and less agglomeration. Furthermore, sonication significantly affected the optical nanocomposite features, leading to an improvement in charge carrier separation and a decrease in the band gap of Ti-Cu-Si (S) by approximately 2.6 eV. Based on the textural results, the ultrasound microjets increased the surface area and pore volume, which facilitate mass transfer and provide suitable adsorption sites for TC molecules. Accordingly, Cu-Ti-Si (S) demonstrated higher adsorption capacity (0.051 g TC/g adsorbent) and eliminated TC significantly faster (0.0054 L.mg-1.min-1) than a non-sonicated sample during 120 min of irradiation, resulting in 2.84 times improvement in the constant rate. In addition, experimental results were accurately modeled using a central composite design in combination with response surface methodology (RSM) and artificial neural networks (ANN) to predict and optimize TC photodegradation. Both RSM and ANN models revealed excellent predictability for TC degradation efficiency, with R2 = 99.47 and 99.71%, respectively. At optimal operational conditions (CTC = 20 ppm, photocatalyst dosage = 1.15 g.L-1, pH = 9, and irradiation time = 100 min), more than 95% and 87% of TC were degraded within the UV (375 W) and simulated solar light (400 W) irradiation periods, respectively. It was observed that the Cu-Ti-Si (S) nanocomposite maintained remarkable stability after four cycles with only a negligible 3% loss of activity, owing to the superior interaction between the bimetallic heterojunction and the silica matrix.

Enhanced tetracycline degradation with TiO2/natural pyrite S-scheme photocatalyst

In this study, TiO2 nanoparticles were employed as a photocatalyst for the degradation of tetracycline (TC) under visible light irradiation. The TiO2 nanoparticles were decorated on natural pyrite (TiO2/NP) and characterized using XRD, FTIR, and SEM-EDX methods. This study evaluated the impacts of various operational parameters such as pH, catalyst dosage, initial TC concentration, and light intensity on TC removal. The findings revealed that under optimal conditions (pH 7, catalyst: 2 g/L, TC: 30 mg/L, and light intensity: 60 mW/cm2), 100% of TC and 84% of TOC were removed within 180 min. The kinetics of TC elimination followed a first-order model. The dominant oxidation species involved in the photocatalytic elimination of TC was found to be ·OH radicals in the TiO2/NP system. The reuse experiments showed the high capability of the catalyst after four consecutive cycles. This study confirmed that the TiO2/NP system has high performance in photocatalytic TC removal under optimized experimental conditions.

A systematic review of photocatalytic degradation of humic acid in aqueous solution using nanoparticles

OBJECTIVES

Humic acid (HA) compounds in the disinfection processes of drinking water and wastewater are considered as precursors of highly toxic, carcinogenic and mutagenic disinfectant by-products. The aim of this study was to systematically review all research studies on the photocatalytic degradation of humic acid and to evaluate the laboratory conditions and results of these studies.

CONTENT

The present systematic review was performed by searching the Scopus, PubMed, and web of science databases until December 2021. The parameters of type of catalyst, catalyst size, optimum pH, optimum initial concentration of humic Acid, optimum catalyst concentration, optimum time, light used and removal efficiency were investigated.

SUMMARY

395 studies were screened and using the inclusion and exclusion criteria, in total, 20 studies met our inclusion criteria and provided the information necessary to Photocatalytic degradation of humic acid by nanoparticles. In the investigated studies, the percentage of photocatalytic degradation of humic acid by nanoparticles was reported to be above 70%, and in some studies, the removal efficiency had reached 100%.

OUTLOOK

From the results of this systematic review, it was concluded that the photocatalytic process using nanoparticles has a high effect on the degradation of humic acid.

Comprehensive analysis of NiFe2O4/MWCNTs nanocomposite to degrade a healthcare waste - tetracycline

Tetracycline (TC), a commonly used antibiotic for studying bacterial illnesses in living organisms, poses a significant risk to the aquatic environment. Despite various conventional methods having been attempted to remove TC antibiotics from water solutions, they have not proven effective. Consequently, the focus of the research is on the photocatalytic degradation of TC. According to the research, MWCNTs were successfully incorporated into NiFe2O4 nanoparticles, which reduced the pace at which charge carriers recombined after joining with MWCNTs. Subsequently, the catalyst's efficacy was assessed in a batch reactor by analyzing the weight percentage change of the nanocomposite, the initial concentration of TC antibiotics, the effects of pH and contact time. The identical operational parameters were employed to investigate the degradation of TC using NiFe2O4 and MWCNTs as individual pure materials. The findings indicated that the photocatalytic process using NiFe2O4/MWCNTs achieved a degradation efficiency of 95.8% for TC at a pH value of 9. This result was obtained after a reaction time of 120 minutes, the concentration of TC solution was 10 mg L-1, with a nanocomposite dose of 0.6 g L-1 of TN 04 and 120 W m-2. The pseudo-first-order approach was used to estimate the rate at which TC degrades. After four consecutive uses, it was observed that the photocatalysts maintained their original properties, with only a slight decrease of approximately 2.4% in the removal efficiency. The study demonstrated that the NiFe2O4/MWCNTs nanocomposite exhibited considerable efficiency in degrading TC. Due to its simple manufacture and useful recovery, it has the potential to function well as a catalyst for the removal and degradation of pharmaceutical organic contaminants.

Biosynthesis of MnFe2O4@TiO2 magnetic nanocomposite using oleaster tree bark for efficient photocatalytic degradation of humic acid in aqueous solutions

The presence of humic acid compounds in water resources, as one of the precursors of Trihalomethanes and Holoacetic acids, causes health problems for many communities. The aim of this research study was to investigate the photocatalytic degradation efficiency of humic acid using MnFe₂O₄@TiO₂ nanoparticles which produced by green synthesis method. The synthesis of metal nanoparticles using plant extracts and the study of their catalytic performance is a relatively new topic. Many chemical techniques have been proposed for the synthesis of MnFe₂O₄@TiO₂ nanoparticles, but green synthesis has received much attention due to its availability, simplicity, and non-toxicity. The properties of synthesized nanoparticles were determined by SEM, FT-IR, XRD, EDS, and DLS analysis. The results of the study showed that under optimal experimental conditions (pH = 3, nanocomposite dose = 0.03 g/L, humic acid initial concentration = 2 mg/L, and contact time = 20 min), it is possible to achieve maximum degradation of humic acid. Therefore; MnFe₂O₄@TiO₂ nanoparticles have high efficiency for removing of humic acid from aqueous solutions under UV light.

Pharmaceutical residues: One of the significant problems in achieving 'clean water for all' and its solution

With the rapid emergence of various metabolic and multiple-drug-resistant infectious diseases, new pharmaceuticals are continuously being introduced in the market. The excess production and use of pharmaceuticals and their untreated/unmetabolized release in the environment cause the contamination of aquatic ecosystem, and thus, compromise the environment and human-health. The present review provides insights into the classification, sources, occurrence, harmful impacts, and existing technologies to curb these problems. A comprehensive detail of various biological and nanotechnological strategies for the removal of pharmaceutical residues from water is critically discussed focusing on their efficiencies, and current limitations to design improved-technologies for their lab-to-field applications. Furthermore, the review highlights and suggests the scope of integrated bionanotechnological methods for enhanced removal of pharmaceutical residues from water to fulfill the United Nations Sustainable Development Goal (UN-SDG) for providing clean potable water for all.

Adsorption of tetracycline by Nicandra physaloides (L.) Gaertn seed gum and Nicandra physaloides(L.) Gaertn seed gum/Carboxymethyl chitosan aerogel

In this study, novel aerogels of Nicandra physaloides (L.) Gaertn seed gum (NPG) and Nicandra physaloides (L.) Gaertn seed gum/Carboxymethyl chitosan (NPG/CMC) were prepared by freeze-drying method for removing tetracycline (TC) from water. Scanning electron microscope (SEM), X-ray diffraction (XRD),Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) were used to characterize structure and morphology of NPG and NPG/CMC aerogels. The average pore diameter of NPG and NPG/CMC were 3.04 and 1.2 nm, the specific surface areas were 2.67 and 0.73 m²/g, respectively. The maximum adsorption capacity of NPG and NPG/CMC aerogels for TC based on Langmuir isotherm was 266.7 and 332.23 mg/g respectively. Through thermodynamic and kinetic studies, it was found that the adsorption processes of the two adsorbents were spontaneous and followed the pseudo-second-order kinetic model. And the process of NPG adsorption of TC was endothermic, while NPG/CMC was exothermic.

Reducing the negative impact of ceftriaxone and doxycycline in aqueous solutions using ferrihydrite/plant-based composites: mechanism pathway

The adsorption of ceftriaxone (CET) and doxycycline (DOX) from aqueous solution using ferrihydrite/plant-based composites (silica rice husk) to reduce their negative impact on the ecosystem was adequately studied. On the other hand, phosphate and humic acid are often found in water and soil; in view of this, their effects on the adsorption of CET and DOX were investigated. The results showed that the removal of ceftriaxone decreased with an increase in pH, while that of doxycycline did not. Ferrihydrite with 10% silica rice husk (Fh-10%SRH) has the highest maximum adsorption capacity of 139 and 178 mg g^-1 for CET and DOX, respectively, at room temperature based on Liu's adsorption isotherm. This implies that the presence of silica rice husk increases CET and DOX uptake due to an increase in the pore volume of FH-10%SRH. The results showed that phosphate had a significant inhibition role on CET adsorption and minor on DOX, whereas humic acid salt affected neither case. Increase in temperature up to 333 K favored the adsorption of both contaminants. The proposed adsorption mechanisms of ceftriaxone are electrostatic interaction, n-π interaction, and hydrogen bond, while that of DOX entails n-π interaction and hydrogen bond.

A review on the adsorption mechanism of different organic contaminants by covalent organic framework (COF) from the aquatic environment

Recently, covalent organic frameworks (COFs) have gained significant attention as a promising material for the elimination of various organic pollutants due to their distinctive characteristics such as high surface area, adjustable porosity, high removal efficiency, and recyclability. The efficiency and selectivity of COFs depend on the decorated functional group and the pore size of the chemical structure. Hence, this review highlights the adsorption removal mechanism of different organic contaminants such as (pharmaceutical and personal care products, pesticides, dyes, and industrial by-products) by COFs from an aqueous solution. Spectroscopic techniques and theoretical calculation methods are introduced to understand the mechanism of the adsorption process. Also, a comparison between the performance of COFs and other adsorbents was discussed. Furthermore, future research directions and challenges encountered in the removal of organic contaminants by COFs are discussed.

Preparation of ZrO2/Graphene Oxide/TiO2 Composite Photocatalyst and Its Studies on Decomposition of Organic Matter

Water polluted by organic dyes is a serious environmental problem. In response to this, the aim of this research is to degrade dye wastewater using a modified photocatalyst. Since sunlight only has less than 5% UV energy, for a general photocatalyst, using sunlight for excitation to decompose organic pollutants is not an effective way. Therefore, we manufactured the modified photocatalyst by zirconium dioxide, graphene oxide, and titanium dioxide. This was to better improve the photo-degradation efficiency for the degradation of organic pollutants. The modified photocatalyst was analyzed by X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), Scanning Electron Microscope (SEM), and Energy-dispersive X-ray spectroscopy (EDS). The results demonstrated that the modified photocatalyst can be activated by the absorption of visible light. Additionally, the band gap of the modified photocatalyst would decrease. The photodegradation percentage of the modified photocatalyst under visible light (Philips TL-D 8W/865 fluorescent tube) for 4 h reached up to 49.92%. At the third test after ultrasonic washing for the cyclic test, the photodegradation percentage of the modified photocatalyst could still maintain at 47.71%. This indicates that the modified photocatalyst has good stability and reusability, and so this can be reused in this regard.

Effect of UVC and UVA Photocatalytic Processes on Tetracycline Removal Using CuS-Coated Magnetic Activated Carbon Nanocomposite: A Comparative Study

In this study, we synthesized a novel MAC nanocomposite using almond’s green hull coated with CuS. The whole set of experiments have been conducted inside a batch (discontinuous reactor system) at room temperature. The effectiveness of different parameters in tetracycline removal pH (3, 5, 7, and 9), pollutant concentration (5–100 mg/L), nanocomposite dosage (0.025–1 g/L), and contact time (5–60 min) using newly synthesized nanocomposite were investigated. Based on the results, in the optimal conditions of pH = 9, nanocomposite dosage of 1 g/L, pollutant concentration of 20 mg/L, contact time of 60 min, and room temperature, 95% removal efficiency was obtained. In MAC/CuS/UV_C process, the removal of COD and TOC were 76.89% and 566.84% respectively meanwhile, these values in MAC/CuS/UV_A process were 74.19% and 62.11%, respectively. The results of nanocomposite stability and magnetic recovery illustrated that the removal efficiency was reduced by 1.5% in the presence of UV_C and 5% in the presence of UV_A lights during all six cycles. Therefore, this nanocomposite was highly capable of recycling and reuse. It can be concluded that considering the high potential of the synthesized nanocomposite, the photocatalytic efficiency of the MAC/CuS/UV_C process in tetracycline synthesis was higher than MAC/CuS/UV_A process.

Application of Magnetic Composites in Removal of Tetracycline through Adsorption and Advanced Oxidation Processes (AOPs): A Review

Water pollution induced by the tetracycline (TC) has caused global increasing attention owing to its extensive use, environmental persistence, and potential harm for human health. Adsorption and advanced oxidation processes (AOPs) have been promising techniques for TC removal due to ideal effectiveness and efficiency. Magnetic composites (MCs) which exploit the combined advantages of nano scale, alternative sources, easy preparation, and separation from wastewater are widely used for catalysis and adsorption. Herein, we intensively reviewed the available literature in order to provide comprehensive insight into the applications and mechanisms of MCs for removal of TC by adsorption and AOPs. The synthesis methods of MCs, the TC adsorption, and removal mechanisms are fully discussed. MCs serve as efficient adsorbents and photocatalysts with superior performance of photocatalytic performance in TC degradation. In addition, the TC can be effectively decomposed by the Fenton-based and SO4•− mediated oxidation under catalysis of the reported MCs with excellent catalytic performance. Based on the existing literature, we further discuss the challenge and future perspectives in MCs-based adsorption and AOPs in removing TC.

Synergetic adsorption and Fenton-like degradation of tetracycline hydrochloride by magnetic spent bleaching earth carbon: Insights into performance and reaction mechanism

In this study, the synergetic adsorption and Fenton-like degradation of tetracycline hydrochloride (TCH) by magnetic spent bleaching earth carbon (Mag-SBE@C) with H₂O₂ were developed and performed, with 91.5% of TCH degradation efficiency and 42.1% of TOC removal efficiency. The effects of the reaction parameters (temperature, initial pH, catalyst dosage, molar ratio of TCH to H₂O₂) on TCH degradation in Mag-SBE@C/H₂O₂ system were studied. Under the optimal conditions (temperature 41.1 °C, initial pH 4.89 and molar ratio of H₂O₂ to TCH 114.435) forecasted by response surface methodology (RSM), high TCH degradation efficiency (99%) was achieved. Also, four cycling tests were performed to confirm the excellent stability and regeneration ability of Mag-SBE@C in presence of H₂O₂. In addition, the characteristics of Mag-SBE@C after reaction are analyzed in details via scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Brunner-Emmet-Teller (BET), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrum (FTIR) and X-ray diffraction (XRD), and it was found that Fe₃O₄ nanoparticles on Mag-SBE@C surface acted as co-catalyst and participated in degradation and improved reaction efficiency, while its properties were not greatly changed. The quenching experiments showed that hydroxyl radicals on Mag-SBE@C surface (OH_adsorption) were dominant in Mag-SBE@C/H₂O₂ system. Meanwhile, three possible TCH degradation pathways were given based on the possible intermediates determined by liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS/MS). Mag-SBE@C is an excellent heterogeneous Fenton-like catalyst, exhibiting greatly potential to antibiotics elimination.

Plasmonic quaternary heteronanostructures (HNSs) for improved solar light utilization, spatial charge separation, and stability in photocatalytic hydrogen production

Recently, the frenetic development of stable quaternary material with a wide range of solar energy absorption and separation of charge carrier has emerged as a favorable material for the solar-to-hydrogen conversion. In this work, quaternary CuS-AgVO₃/Ag-TNR heteronanostructures (HNSs) synthesized by an ultra-sonication method for stabilized solar light photocatalytic hydrogen production in glycerol-water mixture. Among the prepared photocatalysts, the 1 wt% CuS-AgVO₃/Ag-TNR HNS produced the highest H₂ activity (756 µmol/g), approximately 84 times greater than the TNR due to higher charge separation, excellent conductivity, plasmonic resonance effect, and electron-storing capacity. Interestingly, the accelerated charge transfer pathway through the Schottky junction between the AgVO₃ and Ag to the conduction band of the TNR and thereafter to the electron acceptor of CuS for the reduction of H⁺ ions to H₂. Additionally, a possible photocatalytic mechanism of CuS-AgVO₃/Ag-TNR HNS for improved H₂ production was proposed based on the results obtained by various characterization techniques. Therefore, present research work explores the new insights to design high-performance CuS-AgVO₃/Ag-TNR HNS material for the conversion of clean renewable H₂ energy for the futuristic transport applications.

Photocatalytic materials and light-driven continuous processes to remove emerging pharmaceutical pollutants from water and selectively close the carbon cycle

Past and present technologies for wastewater purification and future research directions are critically discussed in this review.

Enhanced Sulfamerazine Removal via Adsorption–Photocatalysis Using Bi2O3–TiO2/PAC Ternary Nanoparticles

The presence of sulfonamides (SAs) in water has received increasing attention due to the risk to ecosystems. The adsorption and photocatalysis performance for sulfamerazine (SMZ) of Bi2O3–TiO2 supported on powdered activated carbon (Bi2O3–TiO2/PAC) nanoparticles was evaluated. The amount of doped Bi2O3 not only influenced the photocatalytic performance but also impacted the adsorption capacity. The adsorption mass transfer mechanism of Bi2O3–TiO2/PAC was elucidated and is further discussed in combination with the photocatalytic mechanism. It was indicated that Bi2O3–TiO2/PAC(10%–700 °C) performed best, and the SMZ removal by the adsorption–photocatalysis of Bi2O3–TiO2/PAC(10%–700 °C) reached 95.5%. Adsorption onto active sites was a major adsorption step, and external diffusion was assisted. Superoxide radical (●O2−) and hole (h+) were identified as the major reactive oxygen species (ROS) for SMZ removal. Benzene ring fracture, SO2 extrusion and nitrogenated SMZ were proposed as the main pathways for photocatalysis. Meanwhile, alkaline conditions enhanced photocatalytic performance, while contrary effects were observed for adsorption. The adsorption–photocatalysis removal performance for SMZ in lake water was better than that for river water. It can be generalized for the potential application of photocatalysis coupling with adsorption to remove refractory antibiotics in water.

Hierarchical N-doped TiO2@Bi2WxMo1-xO6 core-shell nanofibers for boosting visible-light-driven photocatalytic and photoelectrochemical activities

Heterogeneous photocatalysis has been proven to be a promising approach to overcome the great challenges encountered with conventional technologies for environmental remediation. Herein, for the first time, a novel hierarchical architecture of nitrogen-doped TiO₂@Bi₂W_xMo_1-xO₆ (N-T@BWMO-x, x = 0-1.0) was rationally designed and fabricated through an electrospinning route followed by a solvothermal process. The photocatalytic activity of the as-prepared samples was evaluated based on the degradation of tetracycline hydrochloride (TC) under visible-light irradiation. The results indicated that the molar fraction of W/Mo has a strong impact on the photocatalytic efficiency and photoelectrochemical performance of the N-T@BWMO composites. Compared to N-TiO₂ and the binary composites, N-T@BWMO-0.25 exhibited outstanding photocatalytic activity and significant cycling stability. The enhanced photocatalytic activity can be synergistically linked to the excellent native adsorption, extended light-harvesting region, hierarchical structure, and strong interfacial interaction between N-TiO₂ and BWMO, which can effectively prolong the lifetime of charge-carriers. Moreover, active species-trapping and electron paramagnetic resonance results confirmed that holes and superoxide radicals were the dominant active species responsible for TC removal. A possible photocatalytic mechanism underlying the degradation of TC by N-T@BWMO-0.25 is also proposed. We expect that our findings will provide new insights into the use of highly efficient core-shell heterostructure photocatalysts, with potential applications in environmental decontamination.

Photocatalytic degradation of penicillin G from simulated wastewater using the UV/ZnO process: isotherm and kinetic study

PURPOSE

Pharmaceutical contaminants, including antibiotics, present in the environment, especially water resources, are a main concern for human and environmental health due to their stability and non-degradability. Accordingly, the purpose of this study was to investigate the photocatalytic removal of penicillin G antibiotic from simulated wastewater using a photocatalytic process [UV/ZnO] in an isotherm and kinetic study.

METHODS

In the current research, the ZnO nanoparticles [ZnO NPs] were initially characterized by scanning electron microscope [SEM] and X-ray diffraction [XRD]. Then, its efficiency was investigated in the photocatalytic degradation process of penicillin G. The evaluated parameters in the adsorption process penicillin G antibiotic were pH [1-5], penicillin G concentration [10-30 mgL-1], NP dosage [0.5-4.5 gL-1] and contact time [5 to 200 min]. Then, the effect of pH [3, 5, 7, 9, 11, and], penicillin G concentration [10-30 mgL-1], NP dosage [0.01-1.5 gL-1] and contact time [5 to 200 min] in the photocatalytic degradation (UV/ZnO) was studied. The residual penicillin G concentration was measured using a spectrophotometery at a wavelength of 283 nm.

RESULTS

The results indicated that the penicillin G removal efficiency of photocatalytic process [UV/ZnO] using ZnO was 74.65% at the concentration of 10 mgL-1, the pH value of 5, the ZnO NP dosage of 0.1 gL-1 and the contact time of 180 min, as well as the kinetics of degradation followed the pseudo-first-order kinetic model.

CONCLUSION

It can be concluded that the use of this process is appropriate an effective for the removal of the antibiotic pollutants.

A comprehensive study on the application of FeNi3@SiO2@ZnO magnetic nanocomposites as a novel photo-catalyst for degradation of tamoxifen in the presence of simulated sunlight

Pharmaceutical compounds at trace concentrations are found in the environment, especially in drinking water and food, posing significant negative effects on humans as well as on animals. This paper aimed to examine the diagnostic catalytic properties and efficacy of a novel synthesized photocatalyst, namely FeNi₃@SiO₂@ZnO magnetic nanocomposite, for the removal of tamoxifen (TMX) from wastewater under simulated sunlight. According to the results, it was found that TMX was completely degraded operating under optimized conditions (i.e. pH = 7, catalyst dose = 0.01 g/L, initial TMX concentration = 20 mg/L and reaction time = 60 min). The reaction kinetics of TMX degradation followed a pseudo-first order kinetics model. The final by-products from the TMX photodegradation were water, carbon dioxide, acetic acid, nitroacetic acid methyl ester, 2-methyl-2-pentenal, and 4-methyl-2-pentanol. In addition, the synthesized photocatalyst could successfully performed five consecutive photodegradation cycles. The obtained results revealed that the synthesized FeNi₃@SiO₂@ZnO magnetic nanocomposite holds a great potential to be applied as a photocatalyst for the degradation of TMX on an industrial scale.

Ultimate Eradication of the Ciprofloxacin Antibiotic from the Ecosystem by Nanohybrid GO/O-CNTs

Eradication of pharmaceutical drugs from the global ecosystem has received remarkable attention due to the extensive horrible consequences on the human immunological system and the high rate of human deaths. The urgent need for drug eradication became the dominant priority for many research institutions worldwide due to the sharp increase of antimicrobial resistance (AMR) in the human body, which inhibits drug effectiveness and leads ultimately to death. Nanohybrid GO/O-CNTs was fabricated from graphene oxide (GO) cross-linked via calcium ions (Ca²⁺) with oxidized carbon nanotubes (O-CNTs) to eradicate the well-known ciprofloxacin antibiotic drug from aqueous solutions. The ciprofloxacin drug is medically prescribed in millions of medical prescriptions every year and typically exists in domestic and wastewaters. Characterization of the nanohybrid GO/O-CNTs was carried out through spectroscopic (Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD)), thermal (Thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG)), and microscopic (scanning electron microscopy (SEM)) techniques. Optimum parameters for the drug eradication process from aqueous solutions were verified and selected as follows: contact time = 4 h, pH = 6.0, temperature = 290 K, %CaCl₂ = 0.5%, GO/O-CNT ratio = 4:1, and adsorbent mass = 1.0 mg. The equilibrium data were fitted to different adsorption isotherms, and the Langmuir isotherm provided the best fit to our data. Dynamic studies demonstrated a pseudo-second-order removal process for the ciprofloxacin drug, and thermodynamic parameters confirmed exothermic drug adsorption (-27.07 kJ/mol) as well as a physisorption process. For the sake of fighting against the generated AMR, our working strategy demonstrated a removal efficiency of 99.2% of the ciprofloxacin drug and drug uptake as high as 512 mg/g.

Application of response surface methodology for optimization of oxytetracycline hydrochloride degradation using hydrogen peroxide/polystyrene-supported iron phthalocyanine oxidation process

Inspired by metalloporphyrin-based enzymes, a biomimetic catalyst, R-N-Fe, was prepared by grafting iron phthalocyanine (FePc) covalently onto a macroporous chloromethylated polystyrene-divinylbenzene resin (R), which was pre-functionalized using 4-aminopyridine (4-ampy) as an axial ligand. The novel catalyst was used for the degradation of oxytetracycline hydrochloride (OTCH). The response surface methodology was employed to optimize the independent operating parameters, including temperature, catalyst amount, H₂O₂ dosage, and initial pH value. The results displayed that the initial pH and temperature had the most significant effect on the removal efficiency. Under optimum conditions, the OTCH removal efficiency was 93.98%. Additionally, the classical quenching experiment and electron paramagnetic resonance (EPR) test indicated that R-N-Fe could generate hydroxyl radicals by decomposing H₂O₂, which was the main active species for eliminating OTCH. Furthermore, R-N-Fe can be easily recycled and can maintain high stability in the reusability test, rendering it a good potential for practical application.

The practical utility of the synthesis FeNi3@SiO2@TiO2 magnetic nanoparticles as an efficient photocatalyst for the humic acid degradation

Humic acid (HA) compounds in drinking water and wastewater disinfection processes are viewed as precursors of highly toxic, carcinogenic, and mutagenic disinfection by-product chemicals. In recent times, these compounds have gained considerable attention of scientists for their successful removal from aqueous solutions to permissible limits. To achieve this aim, the present study investigated, for the first time, the photocatalytical performance of the synthesis FeNi₃@SiO₂@TiO₂ nanoparticles for the HA degradation under different environmental conditions. The photocatalytic reactions were performed using ultraviolet (UV) radiation, whose intensity was fixed at 2500 μW/cm² throughout the experimental study. The characterization study performed, using specific diagnostic techniques, revealed the presence of several good morphological, magnetic, and catalytic specifications of the synthesized nanoparticles. The use of the simplified form of the Langmuir-Hinshelwood equation sufficiently describes the experimental data of the HA kinetic degradation, as it shows a high coefficient of regression values. Furthermore, the complete HA degradation was reached under conditions of pH = 3; initial HA concentration = 10 mg/L; FeNi₃@SiO₂@TiO₂ nanoparticles dosage = 0.01 g/L; and reaction time >30 min. Thus, the results obtained from this research suggested that the catalyst of FeNi₃@SiO₂@TiO₂ nanoparticles was an attractive, novel, and effective agent, which could be used for the degradation of HA in the photocatalytic processes.

A review on tetracycline removal from aqueous systems by advanced treatment techniques

Tetracycline occurrence and advanced treatment techniques.

Synthesis and characteristics of a novel FeNi3/SiO2/TiO2 magnetic nanocomposites and its application in adsorption of humic acid from simulated wastewater: study of isotherms and kinetics

The presence of natural organic matter such as humic acid in water creates various problems in water purification. Humic acid can react with chlorine in the disinfection step and lead to the production of trihalomethanes and haloacetic acids that these compounds have carcinogenic and mutagenic properties; therefore, they must be removed before arriving to the disinfection stage. The purpose of this research was adsorption of humic acid from simulated wastewater by synthesized FeNi₃/SiO₂/TiO₂ magnetic nanocomposites. FeNi₃/SiO₂/TiO₂ magnetic nanocomposites were synthesized by sol-gel procedure and its characteristics were determined by TEM, VSM, BET, FESEM, and XRD techniques. Then, the effects of such pH (3-11), FeNi₃/SiO₂/TiO₂ dosage (0.005-0.1 g/L), contact time (0-200 min), and initial concentration (2-15 mg/L) were studied on humic acid adsorption using FeNi₃/SiO₂/TiO₂. The results of adsorption experiments revealed that the highest percentage of humic acid removal (94.4%) was achieved at pH 3, initial concentration of 5 ppm, FeNi₃/SiO₂/TiO₂ dose of 0.1 g/L, and contact time of 90 min. The analyses of experimental isotherm data showed that the humic acid adsorption was described by Langmuir model and also the kinetic studies represented that the process of adsorption of humic acid on FeNi₃/SiO₂/TiO₂ was followed by the pseudo-second kinetic. According to the results, it can be concluded that FeNi₃/SiO₂/TiO₂ magnetic nanocomposites have a high ability to absorb humic acid from simulated wastewater.

Ni-doped and Ni/Cr co-doped TiO2 nanotubes for enhancement of photocatalytic degradation of methylene blue

Ni-doped and Ni/Cr co-doped TiO₂ nanotubes were successfully synthesized using a novel hydrothermal method. The surface and bulk properties of as-synthesized nanopowders were characterized using various microstructural and optical techniques. The photocatalytic ability of these nanopowders was investigated systematically for the decomposition of methylene blue dye (MB) under visible light illumination. The morphological results revealed the structural transformation of TiO₂ nanotubes to nanosheets, and further to a mixture of nanosheet/nanotube on doping with Ni and co-doping of Ni/Cr, respectively. Moreover, the Ni doping causes an optical absorption edge shifts towards lower wavelengths, while doping by Ni/Cr results to an optical absorption edge shifts towards higher wavelength in comparison to TiO₂-nanotubes. Also, Ni-doping and Ni/Cr co-doping strongly affects the Raman vibrational modes owing to the changes in interplanar distance, crystallite size, dislocation density, and crystal microstrains. Among the undoped, doped and co-doped TiO₂ nanoparticles, the 6Ni/4Cr co-doped TiO₂ exhibited a higher efficiency of 95.6% and excellent stability towards the photocatalytic degradation of MB. It is attributed to the availability of many carriers for the efficient photo-oxidation within the UV-Vis optical absorption range. Also, the photocatalytic reaction kinetics and degradation mechanism of MB were discussed.

Fixed bed adsorption column studies and models for removal of ibuprofen from aqueous solution by strong adsorbent Nano-clay composite

In this study, ibuprofen was removed using a strong nano-clay-composite based on cloisite 15A, PVP and β-cyclodextrin (CD@clay-PVP) adsorbent through a fixed-bed column system. Chemically modified nano-clay was characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and XRD. Different input situations were evaluated and included adsorbent bed height, initial concentrations, and the impact of the flow rate on the adsorbent. The various mathematical models employed to predict the breakthrough curve and model parameters include Thomas, bed-depth service time (BDST), Yoon-Nelson, and Clark. The characteristics of parameters related to the models were obtained by linear and nonlinear regression to design the process for the columns. Based on error analysis and adsorption conditions, all of the models are identical in describing the adsorption fixed-bed columns.

The synthesis of CB[8]/ZnO composites materials with enhanced photocatalytic activities

Enhancing the separation of hole-electron pairs is one of the valid pathway to enhance the photocatalytic degradation performance of semiconductors. In this work, cucurbit[8]uril/zinc oxide (CB[8]/ZnO) composites were prepared. The structure, morphology, surface elements and optical properties of the composite are characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoemission spectroscopy, thermogravimetric analysis, and specific surface area measurements. In the photocatalytic degradation of 500 mg/L reactive brilliant red X-3B and 400 mg/L reactive yellow X-RG solutions, the rate constant of the CB[8]/ZnO composite is six times that of pure ZnO. A possible photocatalytic degradation mechanism is proposed. Zn²⁺ ions chelate with the carbonyl group of CB[8] on the surface of CB[8]/ZnO. Under ultraviolet-visible light irradiation, the generated holes of ZnO are transferred to and trapped on the CB[8] units to facilitate the separation of electron-hole pairs, improving the photocatalytic performance of this system.

Preparation of Cu2O@TiOF2/TiO2and its photocatalytic degradation of tetracycline hydrochloride wastewater

Cu₂O@TiOF₂/TiO₂composites with large surfaces were prepared by a hydrothermal method and exhibited excellent activity under simulated solar light, showing high efficiency for tetracycline hydrochloride photocatalytic degradation, and reusability.