Tetracycline Hydrochloride Concentration Research Articles

Z-scheme g-C3N4/α-FOD heterojunction-assisted persulfate activation for degradation of tetracycline hydrochloride under visible light: Insights into mechanism

Tetracycline hydrochloride (TCH) as an emerging pollutant poses challenges for removal using traditional treatment methods. A new and high-efficient photocatalyst graphitic carbon nitride/α-ferrous oxalate dihydrate (g-C3N4/α-FOD) was synthesized to solve this issue, which acted as a Z-scheme heterojunction for efficient activation of persulfate (PS) degradation TCH under visible (Vis) light irradiation. A comprehensive characterization of the g-C3N4/α-FOD photocatalyst was performed to analyze the structural, morphological, optical, and electrochemical properties. The Z-scheme heterojunction enabled broader visible-light absorption and enhanced charge transfer. In g-C3N4/α-FOD/PS/Vis system, SO4−, OH, and O2− were identified as the main reactive species and contributed to the efficient degradation of TCH. The initial 100 mg/L TCH concentration can be degraded to 11.3 mg/L within 120 min, reaching a high mineralization rate of 83 %. Density functional theory calculation successfully predicted that the sites on TCH molecules with high Fukui index were preferable to be attacked by the reactive species. The ring contraction and elimination reaction were found to be two major degradation pathways of TCH. The cycling experiments confirmed the good stability and reusability of the g-C3N4/α-FOD photocatalyst. This study successfully confirms that heterojunction materials can enhance the activation potential of PS, which provides a reference for realizing the harmless degradation of environmental pollutants under visible light.

Underwater bubbling plasma assisted with persulfate activation for the synergistic degradation of tetracycline hydrochloride

The performance and mechanism of persulfate consisting of peroxymonosulfate (PMS) and peroxydisulfate (PDS) activation by underwater bubbling plasma (UBP) for the synergistic removal of tetracycline hydrochloride (TCH) were comparatively investigated. Both PMS and PDS addition significantly promoted the removal of TCH in UBP system, indicating persulfate exhibited highly synergistic effect with UBP. Furthermore, enhancing the persulfate dosage, peak voltage and pulse frequency, as well as reducing initial TCH concentration were favorable for the elimination of TCH. Compared with neutral condition, acidic and alkaline condition were advantageous to TCH removal. The presence of coexisting substances including Cl−, SO42− and humic acid (HA) had an adverse effect on TCH degradation, while Fe2+ could improve the removal of TCH. The degradation of ciprofloxacin and metronidazole proved the applicability for other antibiotics degradation of the reaction system. SO4−·, ·OH, ·O2−, hydrated electrons, O3 and H2O2 were the active substances responsible for TCH removal. The reduction of aqueous O3 concentration and enhancement of H2O2 concentration were observed after persulfate addition. UV–vis spectra and TOC analysis illustrated the addition of PMS or PDS facilitated the degradation and mineralization of TCH. 3D-EEMF spectra visually displayed the degradation process of TCH. Plausible degradation routes were deduced based on LC-MS and the toxicities of TCH and its intermediates were evaluated by Toxicity Estimation Software Tool.

Investigation of enhanced degradation of the antibiotic under visible in novel B/ZnO/TiO2 nanocomposite and its electrical energy consumption

Both ZnO and TiO2 are common semiconducting metal oxides with high mechanical and chemical durability. However, they only have good photocatalytic ability in the UV region, besides the rapid recombination between electrons and holes reduces the efficiency of the decomposition of organic substances. To improve their catalytic efficiency, in this study, ZnO and TiO2 were doped with B to produce the novel B/ZnO/TiO2 nanocomposites for degrading tetracycline hydrochloride (TCH) in the aqueous solution. The characteristics of samples were analyzed by the diffuse reflectance ultraviolet–visible (DR/UV–vis), scanning electron microscope (SEM), energy-dispersive (EDS), Fourier transform infrared spectroscopy (FT-IR), and x-ray diffraction (XRD) techniques. The 3B/ZnO/TiO2 sample had a band gap energy (E g) of 3.21 eV. Although the B/ZnO/TiO2 sample had a tightly aggregated morphology composed of many nanoparticles in 33–137 nm, it still exhibited a higher uniformly and photocatalytic efficiency than ZnO and ZnO/TiO2. At the optimal doped B of 3 wt%, the degradation efficiency (DE) was achieved at 96.33% with a rate constant of 0.067 min−1. The factors that affect the photocatalytic process such as the initial TCH concentration, the catalyst content, and the pH solution were comprehensively investigated. In addition, the stability of 3B/ZnO/TiO2 nanocomposite was evaluated via three consecutive cycles and the DE was 69.75% in 3rd cycle. The Z-scheme mechanism was proposed for the photocatalytic mechanism of TCH in the B/ZnO/TiO2 catalyst. In addition, electrical energy consumption was estimated that the electrical energy per order only was 29.05 kW.h.l−1.

Fe, Mn-Prussian blue analogue@MXene composites for efficient photocatalytic peroxydisulfate-activated degradation of tetracycline hydrochloride and photoelectrochemical desalination

The utilization of wastewater or saline as a source of clean and safe freshwater is a potential solution to address water pollution and scarcity. In this study, we synthesized a composite material, i. e. Fe, Mn-Prussian blue analogue@MXene, which is highly responsive to visible light and serves as an innovative activator for peroxydisulfate (PDS) in the degradation of tetracycline hydrochloride (TCH). The FeMn-PBA@MXene-0.30 composite, with its unique metal-organic framework (MOF) structure, exhibited excellent photocatalytic activity in the degradation of TCH by activating PDS through dual redox cycles of Mn(II)–C≡N–Fe(III) and Mn(III)–C≡N–Fe(II). A remarkable 93.41% removal of TCH can be achieved at a concentration of 30 mg·L−1 within 120 min. The presence of MXene in the composite may facilitate the efficient electron transportation owing to its excellent conductivity. The influences of various reaction conditions are also investigated, such as the concentration of potassium persulfate (KPS), TCH concentration, and solution pH value. Electron spin resonance (ESR) analysis and trapping experiments revealed the presence of reactive species, including 1O2, ∙OH, and h+, in the FeMn-PBA@MXene-0.30/visible light/PDS system. Furthermore, we demonstrated the application of the FeMn-PBA@MXene-0.30 composite as the photoanode of a solar-assisted photoelectrochemical desalination (SA-PED) device, which combines the TCH degradation with photoelectrochemical desalination. This novel approach enabled simultaneous degradation and desalination, resulting in a significant reduction of 4000-ppm brine to 240 ppm (lower than the freshwater threshold of 500 ppm), with a salt removal efficiency (SRE) of 94.00%. Meanwhile, the degradation rate of TCH (900 mg·L−1) reached up to 98.91% under visible light irradiation. This work not only provides valuable insights into the development of PDS-activated catalysts but also explores new avenues for the multifunctional application of photocatalysts in addressing water pollution and scarcity.

Effect of tetracycline hydrochloride application on dental pulp stem cell metabolism-booster or obstacle for tissue engineering?

Introduction: Stem cells and scaffolds are an important foundation and starting point for tissue engineering. Human dental pulp stem cells (DPSC) are mesenchymal stem cells with self-renewal and multi-directional differentiation potential, and are ideal candidates for tissue engineering due to their excellent biological properties and accessibility without causing major trauma at the donor site. Tetracycline hydrochloride (TCH), a broad-spectrum antibiotic, has been widely used in recent years for the synthesis of cellular scaffolds to reduce the incidence of postoperative infections. Methods: In order to evaluate the effects of TCH on DPSC, the metabolism of DPSC in different concentrations of TCH environment was tested. Moreover, cell morphology, survival rates, proliferation rates, cell migration rates and differentiation abilities of DPSC at TCH concentrations of 0-500μg/ml were measured. Phalloidin staining, live-dead staining, MTS assay, cell scratch assay and real-time PCR techniques were used to detect the changes in DPSC under varies TCH concentrations. Results: At TCH concentrations higher than 250μg/ml, DPSC cells were sequestered, the proportion of dead cells increased, and the cell proliferation capacity and cell migration capacity decreased. The osteogenic and adipogenic differentiation abilities of DPSC, however, were already inhibited at TCH con-centrations higher than 50μg/ml. Here, the expression of the osteogenic genes, runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN), the lipogenic genes lipase (LPL), as well as the peroxisome proliferator-activated receptor-γ (PPAR-γ) expression were found to be down-regulated. Discussion: The results of the study indicated that TCH in concentrations above 50µg/ml negatively affects the differentiation capability of DPSC. In addition, TCH at concentrations above 250µg/ml adversely affects the growth status, percentage of living cells, proliferation and migration ability of cells.

Ba0.5Sr0.5TiO3/BaFe12O19 magnetic separation photocatalysts: Structural, optical, microstructure, photocatalytic activity, degradation pathway and mechanism

The Ba0.5Sr0.5TiO3/BaFe12O19 (BST5/BFO) magnetic photocatalysts were constructed by a polyacrylamide gel route combined with low temperature heat treatment process. The effect of different BFO contents on the phase, surface microstructure, magnetic and optical properties, and photocatalytic efficiency of BST5/BFO magnetic photocatalysts was investigated. The BST5, BFO and BST5/BFO magnetic photocatalysts were evaluated for the degradation of tetracycline hydrochloride (TC) under simulated sunlight irradiation for 120 min, pH=5, catalyst content of 1 g/L, initial TC concentration of 50 mg/L and the photocatalytic efficiency trend followed the order: pristine BFO < pristine BST5 < BST5/20%BFO < BST5/15%BFO < BST5/5%BFO <BST5/10%BFO. The improvement of photocatalytic efficiency of BST5/BFO magnetic photocatalyst is mainly attributed to the synergistic effect of optical absorption coefficient, squareness ratio (SQR), interface charge transfer and separation efficiency due to the impurity defect and magnetic field induced the formation of oxygen vacancy, hole, hydroxyl radical and superoxide radical. The reasonable photocatalytic mechanism of BST5/BFO magnetic photocatalysts and possible intermediate products were elucidated in detail on the basis of the first principles calculation, capture experiment, radical verification experiment, magnetic data and liquid chromatography-mass spectrometry.

Novel Z-scheme MgFe2O4/Bi2WO6 heterojunction for efficient photocatalytic degradation of tetracycline hydrochloride: Mechanistic insight, degradation pathways and density functional theory calculations

In this study, a new Z-scheme MgFe2O4/Bi2WO6 heterojunction was successfully prepared by hydrothermal and wet ball milling process. The results of the study showed that after 90 min of visible light exposure, the photocatalytic degradation of tetracycline hydrochloride (TCH) by 25%-MgFe2O4/Bi2WO6 heterojunction was as high as 95.82%, and the highest photocatalytic rate (0.0281 min−1) was 4.61 and 3.43 times higher than that of pure Bi2WO6 (0.0061 min−1) and MgFe2O4 (0.0082 min−1), respectively. Furthermore, spin-polarized density functional theory (DFT) calculations were performed to provide additional evidence of the presence of a Z-scheme charge transfer mechanism between MgFe2O4 and Bi2WO6. We investigated the effects of initial TCH concentration, pH, coexisting ions and different water sources on the efficiency of photocatalytic degradation of TCH in composite samples. The recovery experiments demonstrated that the MgFe2O4/Bi2WO6 composites had good stability and repeatability. A series of experimental results showed that 25%-MgFe2O4/Bi2WO6 had a larger specific surface area, better ultraviolet and visible absorbance, superior charge transfer and higher efficiency of photogenerated electron-hole pair separation. This paper provides new ideas for the design and preparation of new Z-scheme heterojunctions and has great prospects for practical applications in the field of wastewater treatment.

S–Modified MXene as a Catalyst for Accelerated Tetracycline Hydrochloride Electrocatalytic Degradation via ·OH and Active Chlorine Triggering Promotion

S–modified MXene (Ti3C2Tx@S–5) was prepared to improve the catalytic activity of MXene in the electrocatalytic degradation of tetracycline hydrochloride (TC). Here, S groups in the form of Ti–S and S–O species were anchored onto MXene, resulting in superior conductivity and surface activity. Ti3C2Tx@S–5 exhibited an excellent performance of 100% TC degradation under the conditions of 25 °C, a pH of 6, a TC concentration of 10 mg L−1, and an applied current of 20 mA. Radical quenching and EPR analyses revealed that ·O2− and 1O2 played dominant roles in Ti3C2Tx@S–5 and Ti3C2Tx systems. Furthermore, S modification promoted the triggering of ·OH and active chlorine, which contributed to the acceleration of TC degradation. The involvement of these active substances in degradation pathways was further proven. This research advances the S modification of MXene and improves TC degradation by promoting the triggering of ·OH and active chlorine, broadening the applicability of MXene material.

Activation of persulfate with magnetic Fe3O4-municipal solid waste incineration bottom ash-derived zeolite core–shell materials for tetracycline hydrochloride degradation

ABSTRACT A novel and environmentally friendly magnetic iron zeolite (MIZ) core–shell were successfully fabricated using municipal solid waste incineration bottom ash-derived zeolite (MWZ) coated with Fe3O4 and innovatively investigated as a heterogeneous persulfate (PS) catalyst. The morphology and structure composition of as-prepared catalysts were characterised, and it was proved that the core–shell structure of MIZ was successfully synthesised by coating Fe3O4 uniformly on the MWZ surface. The tetracycline hydrochloride (TCH) degradation experiment indicate that the optimum equimolar amount of iron precursors was 3 mmol (MIZ-3). Compared with other systems, MIZ-3 possessed a superior catalytic performance, and the degradation efficiency of TCH (50 mg·L−1) in the MIZ-3/PS system reached 87.3%. The effects of reaction parameters on the catalytic activity of MIZ-3, including pH, initial concentration of TCH, temperature, the dosage of catalyst, and Na2S2O8, were assessed. The catalyst had high stability according to three recycling experiments and the leaching test of iron ions. Furthermore, the working mechanism of the MIZ-3/PS system to TCH was discussed. The electron spin resonance (ESR) results demonstrated that the reactive radicals generated in the MIZ-3/PS system were sulphate radical () and hydroxyl radical (•OH). This work provided a novel strategy for TCH degradation under PS with a broad perspective on the fabrication of non-toxic and low-cost catalysts in practical wastewater treatment.

Development and Validation of Simultaneous Spectroscopic Method for Tetracycline Hydrochloride and Clotrimazole

Abstract: A simple and accurate simultaneous method was developed for tetracycline hydrochloride (TH) and clotrimazole with a mixture of solvents. the combination is used to Validate the developed UV-spectrophotometric method as per ICH guidelines, The concentration of Tetracycline hydrochloride &amp; clotrimazole in the sample solution was determined by solving the respective simultaneous equations generated by using absorptivity coefficients and absorbance values of TH &amp; Clotrimazole at these wavelengths 361 nm and 259 nm respectively. and both satisfy Beer's law in concentration ranges of 4-20 µg/ml for TH and 10- 30 µg/ml for Clotrimazole. The method was effectively used to estimate TH and clotrimazole in Buccal film without the interference of common excipients.

Visible-light-driven AgI/Bi4O5I2 S-scheme heterojunction for efficient tetracycline hydrochloride removal: Mechanism and degradation pathway

The existence of excessive tetracycline hydrochloride (TCH) in the ecological environment has seriously threatened human health, so there is an urgent need to develop a high-performance photocatalyst that can efficiently and greenly remove TCH. Currently, most photocatalysts have the problems of fast recombination of photogenerated charge carriers and low degradation efficiency. Herein, S-scheme AgI/Bi4O5I2 (AB) heterojunctions was constructed for TCH removal. Compared with the single component, the apparent kinetic constant of the 0.7AB is 5.6 and 10.2 time as high as the AgI and Bi4O5I2, and the photocatalytic activity only decreases by 3.0% after four recycle runs. In addition, to verify the potential practical application of the fabricated AgI/Bi4O5I2 nanocomposite, the photocatalytic degradation of TCH was performed under different conditions by regulating the dosage of photocatalyst, the TCH concentration, pH, and the existence of various anions. Systematical characterizations are conducted to investigate the intrinsic physical and chemical properties of the constructed AgI/Bi4O5I2 composites. Based on the synergetic characterizations by in situ X-ray photoelectron spectroscopy, band edge measurements, as well as reactive oxygen species (ROS) detections, the S-scheme photocatalytic mechanism is proved. This work provides a valuable reference for developing efficient and stable S-scheme AgI/Bi4O5I2 photocatalyst for TCH removal.

Construction of MXene/Ti membrane electrode with Ti3C2TX via electrophoretic deposition for high-efficient electrochemical degradation of antibiotic wastewater

The introduction of antibiotics into the environment leads to serious environmental problems and public health concerns. Along these lines, in this work, a facile strategy to fabricate the MXene/Ti membrane was developed by loading 2D ultrathin Ti3C2Tx nanosheets on the porous Ti membrane through electrophoretic deposition, which was used as anode material for the degradation of the tetracycline hydrochloride (TCH) wastewater in the electrocatalytic membrane reactor (ECMR). From the acquired degradation results, it was demonstrated that the removal efficiency of TCH and total organic carbon (TOC) was nearly 100 % and 90.4 % with the obtained MXene/Ti anode in the ECMR, respectively, under a temperature value of 20 °C, a current density of 0.8 mA cm−2, a residence time of 10 min, an electrolyte Na2SO4 concentration of 15 g L−1, a TCH concentration of 50 mg L−1, and a pH of 7.0 reaction conditions. These values were much higher than that of pristine Ti membrane anode and other reported electrochemical treatment processes, such as electrocatalysis, photo-electrocatalysis process etc. The excellent stability of the MXene/Ti anode was also demonstrated by performing 15 cycles test. The superior removal efficiency of TCH and the mineralization ability of antibiotics could be ascribed to the formation of 2D nanocomposites of Ti3C2Tx and TiO2. Our work paves the way for the utilization of MXene/Ti membrane electrodes and ECMR for the efficient removal of antibiotics from wastewater.

Fabrication of electrochemical sensor based on MnO2 nanorods for tetracycline detection

ABSTRACT A highly efficient, green and simple method has been reported, for the detection of tetracycline at μM level. An improved redox co-precipitation method was used to make highly MnO2 nanorods from MnCl2.4 H2O and KMnO4. High-resolution transmission electron microscopy (HRTEM) analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett Teller (BET) surface area analysis were used to describe the structure and morphology of the material. The MnO2 material was amorphous and mesoporous, with a surface area of 89.908 m2/g and an average pore size of 6.023 nm. The oxidising property of the produced nano MnO2, as well as its porosity and surface area, have rendered the MnO2 material a potent sensor for tetracycline hydrochloride (TC) detection in an aqueous medium at room temperature. The effect of pH, MnO2 dosage of TC was more favourable at pH 5. The sensor has good electrochemical performance, with a linear response for TC concentration varying from 1 μM to 1 mM and a Limit of Detection (LOD) of 0.513 µM. Furthermore, the prepared sensor exhibited excellent repeatability, portability, reproducibility, specificity, sensitivity and was cost-effective, all of which were the characteristics of a good electrochemical sensor material. The synthesised sensor was employed to determine TC in real-world samples (water and food) to demonstrate its capabilities.

Removal of Tetracycline Hydrochloride by Photocatalysis Using Electrospun PAN Nanofibrous Membranes Coated with g-C3N4/Ti3C2/Ag3PO4.

In order to improve the photocatalytic performance of g-C3N4, the g-C3N4/Ti3C2/Ag3PO4 S-type heterojunction catalyst was prepared by electrostatic assembly method, and then the g-C3N4/Ti3C2/Ag3PO4/PAN composite nanofiber membrane was prepared by electrospinning technology. The morphology and chemical properties of the nanofiber membrane were characterized by SEM, FTIR, and XRD, and the photocatalytic degradation of tetracycline hydrochloride (TC) in water by the nanofiber membrane was investigated. The results showed that g-C3N4/Ti3C2/Ag3PO4 could be successfully loaded on PAN and uniformly distributed on the surface of composite nanofiber membrane by electrospinning technology. Increasing the amount of loading and catalyst, lowering the pH value and TC concentration of the system were conducive to the oxidation and degradation of TC. The nano-fiber catalytic membrane had been recycled five times and found to have excellent photocatalytic stability and reusability. The study of catalytic mechanism showed that h+, •OH and •O2- were produced and participated in the oxidation degradation reaction of TC, and •O2- plays a major role in catalysis. Therefore, this work provides a new insight into the construction of high-performance and high-stability photocatalytic system by electrospinning technology.

Mechanistic study of B-TiO2/BiVO4 S-scheme heterojunction photocatalyst for tetracycline hydrochloride removal and H2 production

S-schemed photocatalysts have been employed extensively to address energy issues and environmental contaminants because of their high redox ability and effective separation of photocharges. In this study, a novel S-scheme B-TiO2/BiVO4 photocatalyst was successfully fabricated using a simple in-situ hydrothermal method to enhance tetracycline hydrochloride (TCH) degradation and H2 evolution. The unique composition of B-TiO2 and BiVO4, as well as their synergistic effect, increased the number of multidimensional active reaction sites and enhanced the efficiency of photogenerated electron pair separation. In particular, when exposed to visible light, the rate of H2 evolution increased to 561.99 μmol·g−1·h−1, and the rate of TCH breakdown increased to 89.30 % in 120 min. The effects of initial pH, catalyst dosage, TCH concentration, and various coexisting anions were studied. It was discovered that pH and various anions had the greatest impact on the photocatalytic performance of B-TiO2/BiVO4 for the breakdown of TCH. In addition, free radical capture experiments and Electron paramagnetic resonance (EPR) revealed that ·O2− and h+ were the most important reactive species that accelerated the photocatalytic activities of B-TiO2/BiVO4. Work function calculations demonstrated that the presence of internal electric field (IEF) in the special B-TiO2/BiVO4 heterojunction, indicating the formation of an S-scheme heterojunction in the B-TiO2/BiVO4 system, which greatly facilitated the separation of electron-hole (e−-h+) pairs to promote efficient TCH degradation and hydrogen production. This study provides a potential strategy for developing high-performance photocatalysts that can produce clean energy without negatively impacting the environment.

Photocatalysis Combined with Microalgae to Promote the Degradation and Detoxification of Tetracycline Hydrochloride

The continuous discharge of antibiotics into the environment poses a serious threat to the ecological environment and human health. In this study, photocatalysis and microalgae were combined to study the removal of tetracycline hydrochloride (TCH) and its photodegradation intermediates in water. The results showed that after photocatalytic treatment, the removal rate of TCH reached 80%, but the mineralization rate was only 17.7%. While Chlorella sp. alone had poor tolerance to high concentrations of TCH, the combined treatment of photocatalysis and microalgae completely removed TCH and increased the mineralization efficiency to 35.0%. Increased cell density was observed, indicating that TCH and the intermediates produced in the photocatalysis process could be utilized by algae for growth. Meanwhile, TCH degradation pathways were proposed based on Liquid Chromatograph Mass Spectrometer analysis, and the toxicity of intermediates detected was predicted using ECOSAR software, which showed that the type and quantity of highly toxic intermediates decreased significantly after subsequent algal treatment. The results demonstrate that photocatalysis and microalgae combined treatment is an efficient and eco-friendly method for the removal of antibiotics in water.

Arang Aktif Ampas Tebu Termodifikasi Kitosan sebagai Adsorben Tetrasiklin: Pemanfaatan Metode Kolom

Currently, antibiotics are considered environmental pollutants because of their undesirable effects on human health and the environment, including the waste of antibiotics tetracycline hydrochloride. While on the other hand, bagasse is an agricultural waste that has no economic value. This study aims to study the characteristics of activated charcoal from bagasse and the use of bagasse as chitosan-modified activated charcoal using the column method to determine the variation of adsorbent height, flow rate, and acidity of the solution in the ability of the bagasse adsorbent to adsorb tetracycline hydrochloride. Bagasse goes through a carbonation process using a furnace at a temperature of 350°C until charcoal is formed. The next process is activation using 2 M phosphoric acids and compared based on SNI 06-3730-1995 regarding technically activated charcoal. Determination of functional groups using Fourier Transform Infra-Red, adsorbent morphology using Scanning Electron Microscope, and crystallinity using X-Ray Diffraction. The concentration of tetracycline hydrochloride before and after adsorption was measured using an Ultra Violet-Visible spectrophotometer. The best absorption results in the adsorption process were found at the adsorbent height of 14 cm (99%), the flow rate of 0.5mL/minute (92%), and pH 4 (93%).

Chitosan-Activated Charcoal of Modified Corn Cobs as an Antibiotics Adsorbent

Excessive use of tetracycline hydrochloride can cause water pollution. The concentration of tetracycline hydrochloride in an aqueous solution can be reduced by an adsorption method that utilizes activated charcoal as an adsorbent. This study aims to determine the effect of the addition of chitosan on the characteristics of activated charcoal, the effect of pH, adsorption kinetics, the adsorption isotherm, and the effect of sonication on adsorption ability. The method used in this research is the batch method combined with the sonication method. Based on this research, it is known that the use of ultrasonic waves (sonication) can streamline the adsorption process of tetracycline hydrochloride. The time required for the adsorption process is faster with greater adsorption capacity and efficiency. Tetracycline solution can be absorbed optimally at an acidic pH, which is pH 4. The adsorption process using the sonication method can increase the adsorption capacity from 2.092 mg.g-1 to 5.330 mg.g-1. The adsorption mechanism in both methods (batch and sonication) that occurs follows the kinetic equation of the two Ho pessaries. In contrast to adsorption kinetics, the adsorption isotherm for the batch method corresponds to the Langmuir adsorption isotherm equation (R2 = 0.950), while the use of the sonication method corresponds to the Freundlich isotherm equation (R2 = 0.859). Thus, corn cob waste can be utilized by converting it into activated charcoal modified by chitosan as an adsorbent for antibiotic waste, especially tetracycline hydrochloride.

Promotion of O2 activation by ZIF-8 derived N-rich aluminum-graphite (Al-Gr-NPC) composite for non-radical degradation of antibiotic at neutral pH

Recently, the activation of molecular oxygen (O2) by graphite (Gr) supported aluminum (Al) composite for the in-situ generation of H2O2/OH gains increasing attention. However, the limited O2 mass transfer and low catalytic activity of decomposition H2O2 at neutral pH restrict its further application in the wastewater treatment. In this work, a novel N-rich graphite supported aluminum (Al-Gr-NPC) composite was fabricated by introducing the nitrogen-rich porous carbon (NPC) obtained from ZIF-8 derivative as precursor, and by a ball-milling and sintering process. The results showed that the NPC introduction not only improved the physiochemical property of Al-Gr, such as specific surface area, pore structure and hydrophobicity, facilitating the mass transfer of O2, but also made Al-Gr contain plentiful N species, serving as active sites for the two-electron ORR process and catalytic decomposition of H2O2. These excellent performances of Al-Gr-NPC favored the production and utilization of H2O2 by the activation of O2 at neutral pH and air aeration. The carbonization temperature of ZIF-8 determined the type of N species, surface area and the hydrophobicity of NPC. 1O2 was the main oxidant for tetracycline hydrochloride (TC) degradation. 100 % TC degradation and 60.57 % of TOC removal were achieved within 60 min at neutral pH, Al-Gr-NPC dosage of 0.5 g/L and initial TC concentration of 20 mg/L. The toxicity of the final products of TC degradation were much lower than TC by ECOSAR software analysis. Al-Gr-NPC could be used for the removal of antibiotic contaminants from wastewater.

Ultrasound-activated peracetic acid to degrade tetracycline hydrochloride: Efficiency and mechanism

The removal of pollutants by peraceticacid (PAA) has attracted much attention. However, such removal is not achievable solely by PAA without activation. This paper investigated the efficiency and mechanism of ultrasound-activated peracetic acid (US/PAA) to remove tetracycline hydrochloride (TCH). The results indicated that US/PAA process could successfully remove organic contaminants from water, and the degradation efficiency of TCH could reach 99.4% within 30 min. Adding ultrasonic radiation into the PAA solution could effectively activate PAA, and the US/PAA process increased the degradation efficiency of TCH by 4.88 times compared to the PAA process. The electron paramagnetic resonance (EPR) experiment and the radical quenching experiment both demonstrated that singlet oxygen (1O2) and organic radicals (RO·) played an important role in the degradation of TCH during US/PAA process. The effects of the PAA dose, pH, ultrasound power, and initial TCH concentration on the removal of TCH in US/PAA process were investigated. The pH was the main factor, and the highest degradation efficiency was reached at a neutral pH (6.5–8.0). Additionally, the influence of water components (Cl−, HCO3−, SO42−, and humic acid) on the removal of TCH by US/PAA process was studied. The results showed that all water components inhibited the elimination of TCH, except 5 mmol/L HCO3−. Finally, the possible degradation products of TCH were identified by high performance liquid chromatography triple quadrupole mass spectrometer (HPLC-MS) analysis, and the potential degradation pathways mainly involved hydroxylation, demethylation, dehydration, and ring cleavage reaction.