Tetracycline In Wastewater Research Articles

Preparation and characterizations of TiO2/ZnO nanohybrid and its application in photocatalytic degradation of tetracycline in wastewater

The photodegradation of tetracycline antibiotics (TC) in an aqueous solution, using the TiO2 nanoparticles, ZnO microparticles, and TiO2/ZnO composite under the UV lamp in a continuous reactor, was performed. The effects of different parameters, such as the initial TC concentration, medium pH, ratio of each photocatalyst, and the flow rate were comprehensively studied. SEM, EDX, and XRD characterization techniques were employed to study the morphology and structure features of the prepared composite. The results revealed that a more significant amount of TC is not easily removed from wastewater. Furthermore, by increasing the pH of the medium to 11, the efficiency of TC degradation was increased, while the amount of removal remained stable at higher pH values. As the flow rate increased up to 190 mL/min, the removal efficiency increased; however, at higher flow rates, lower efficiency was obtained. Moreover, using multivariate analysis and response surface methodology (RSM), a model for removing TC and the effect of experimental parameters on removal efficiency was proposed. The optimal conditions using the RSM method were found to be the reduction efficiency of 78.94 % in pH = 11 (flow rate of 132 mL/min, and TiO2 concentration of 323 mg) and reduction efficiency of 75.89% in pH = 9 (flow rate of 143.19 mL/min and TiO2 concentration of 312.73 mg).

Degradation of tetracyclines via calcium peroxide activation by ultrasonic: Roles of reactive species, oxidation mechanism and toxicity evaluation

Tetracyclines (TC) frequently detected in the aqueous environment pose threats to humans and ecosystems. The synergistic technology coupling ultrasound (US) and calcium peroxide (CaO2) has a great potential to abate TC in wastewater. However, the degradation efficiency and detailed mechanism of TC removal in the US/CaO2 system is unclear. This work was carried out to assess the performance and mechanism of TC removal in the US/CaO2 system. The results demonstrated that 99.2% of TC was degraded by the combination of 15 mM CaO2 with ultrasonic power of 400 W (20 kHz), but only about 30% and 4.5% of TC was removed by CaO2 (15 mM) or US (400 W) alone process, respectively. Experiments using specific quenchers and electron paramagnetic resonance (EPR) analysis indicated that the generation of hydroxyl radicals (•OH), superoxide radicals (O2−•), and single oxygen (1O2) in the process, whereas •OH and 1O2 were mainly responsible for the degradation of TC. The removal of TC in the US/CaO2 system has a close relationship with the ultrasonic power, the dosage of CaO2 and TC, and the initial pH. The degradation pathway of TC in the US/CaO2 process was proposed based on the detected oxidation products, and it mainly included N,N-dedimethylation, hydroxylation, and ring-opening reactions. The presence of 10 mM common inorganic anions including chloridion (Cl−), nitrate ion (NO3−), sulfate ion (SO42−), and bicarbonate ion (HCO3−) showed negligible influences on the removal of TC in the US/CaO2 system. The US/CaO2 process could efficiently remove TC in real wastewater. Overall, this work firstly demonstrated that •OH and 1O2 mainly contributed to the removal of pollutants in the US/CaO2 system, which was remarkable for understanding the mechanisms of CaO2-based oxidation process and its future application.

Preparation of Co-CNK-OH and Its Performance in Fenton-like Photocatalytic Degradation of Tetracycline

In this study, Co-modified alkalinized g-C3N4 (named Co-CNK-OH) was prepared for the Fenton-like photocatalytic degradation of tetracycline (TC) via a simple yet effective calcination–impregnation method. In all samples of CNK-OH with different Co2+ loadings, Co-CNK-OH catalyst with the optimal content (9%) exhibited the highest catalytic activity, with 87.1% tetracycline removal and 50% removal efficiency of the total organic carbon (TOC). Mechanism studies revealed that the 9%Co-CNK-OH catalyst had the lower electrical resistance after alkalization treatment and Co2+ modification, leading to a significantly accelerated interfacial charge transfer to the electron acceptor as well as effectively separating electrons and holes. The intermediates generated during the TC degradation in the photo-Fenton process were detected by HPLC-MS, which proved that the holes, superoxide radicals, and singlet oxygen are the key reactive species in the Fenton-like photocatalysis. This study provides a new option for the treatment of TC in wastewater.

Photocatalytic synergistic biofilms enhance tetracycline degradation and conversion.

Tetracyclines are refractory pollutants that cause persistent harm to the environment and human health. Therefore, it is urgently necessary to develop methods to promote the efficient degradation and conversion of tetracyclines in wastewater. This report proposes a photobiocatalytic synergistic system involving the coupling of GeO2/Zn-doped phosphotungstic acid hydrate/TiO2 (GeO2/Zn-HPW/TiO2)-loaded photocatalytic optical hollow fibers (POHFs) and an algal-bacterial biofilm. The GeO2/Zn-HPW/TiO2 photocatalyst exhibits a broad absorption edge extending to 1000 nm, as well as high-efficiency photoelectric conversion and electron transfer, which allow the GeO2/Zn-HPW/TiO2-coated POHFs to provide high light intensity to promote biofilm growth. The resulting high photocatalytic activity rapidly and stably reduces the toxicity and increases the biodegradability of tetracycline-containing wastewater. The biofilm enriched with Salinarimonas, Coelastrella sp., and Rhizobium, maintains its activity for the rapid photocatalytic degradation and biotransformation of intermediates to generate the O2 required for photocatalysis. Overall, the synergistic photocatalytic biofilm system developed herein provides an effective and efficient approach for the rapid degradation and conversion of water containing high concentrations of tetracycline.

Highly graphitic Fe-doped carbon xerogels as dual-functional electro-Fenton catalysts for the degradation of tetracycline in wastewater

Fe-doped carbon xerogels with a highly developed graphitic structure were synthesized by a one-step sol-gel polymerization. These highly graphitic Fe-doped carbons are presented as promising dual-functional electro-Fenton catalysts to perform both the electro-reduction of O2 to H2O2 and H2O2 catalytic decomposition (Fenton) for wastewater decontamination. The amount of Fe is key to the development of this electrode material, since affects the textural properties; catalyzes the development of graphitic clusters improving the electrode conductivity; and influences the O2-catalyst interaction controlling the H2O2 selectivity but, at the same time is the catalyst for the decomposition of the electrogenerated H2O2 to OH• radicals for the organic pollutants oxidation. All materials achieve the development of ORR via the 2-electron route. The presence of Fe considerably improves the electro-catalytic activity. However, a mechanism change seems to occur at around −0.5 V in highly Fe-doped samples. At potential lower than −0.5 eV, the present of Feδ+ species or even Fe–O–C active sites favour the selectivity to 2e-pathway, however at higher potentials, Feδ+ species are reduced favoring a O–O strong interaction enhancing the 4e-pathway. The Electro-Fenton degradation of tetracycline was analyzed. The TTC degradation is almost complete (95.13%) after 7 h of reaction without using any external Fenton-catalysts.

Simulation monitoring of tetracyclines in wastewater based on fluorescence image processing and machine learning classifier

Antibiotics, as an emerging pollutant, have attracted extensive attention due to their trace residues and toxic side effects in the environment. Here, we constructed a new detection mechanism for tetracyclines in sewage by online trace sensing through machine learning (ML) algorithm and image fingerprint extraction method. The image fingerprint information was obtained from the blue to red specific fluorescence response generated by the interaction between the luminescent metal-organic framework (MOF) with tetracyclines, which greatly improved the ability against background interference. Fluorescence images of samples with different concentrations were collected, and the RGB mean value of sample images was extracted through the program as "fingerprint information". Then k-means clustering model (KCM) and hierarchical clustering model (HCM) were constructed to analyze the differences in fingerprint information of samples with different concentrations by clustering analysis method in machine learning. The clustering results showed good clustering characteristics of samples with similar concentrations, which provided reliable support for rapid detection while avoiding the use of expensive large instruments and time-consuming analysis methods.

A novel core-shell Z-scheme heterojunction In2O3@BiFeO3 with broad spectrum response for enhanced photocatalytic degradation of tetracycline

Photocatalysis is proven as a desirable technology for elimination of the tetracyclines pollutant from wastewater. Herein, a novel core-shell Z-scheme heterojunction In2O3@BiFeO3 was, for the first time, fabricated via facile hydrothermal method to effectively eliminate tetracycline in wastewater. The prepared photocatalysts were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), UV–vis spectroscopy and so on. The photocatalytic performance of the prepared samples was evaluated by photo-degradation of tetracycline (TC) under visible light. TC degradation results demonstrated that the as-prepared In2O3@BiFeO3 obeyed the pseudo-first-order kinetics and exhibited a higher photocatalytic rate of 0.01173min−1 that was approximately 2.97 and 14.4 folds those of the raw BiFeO3 and In2O3, respectively. Additionally, In2O3@BiFeO3 possessed high stability during five consecutive cycles. The core-shell structure and the photosensitization of BiFeO3 significantly improved light-absorption in the entire visible region. The enhanced photocatalytic activity is attributed to the improved light harvesting and the effective separation of photogenerated electron-hole pairs due to the formation of core-shell Z-Scheme heterojunction. Due to the well-matched band position of In2O3 and BiFeO3, •OH, •O2− and h+ all act as primary reactive species in TC degradation. This research provides a new strategy to construct the promising visible-light-driven photocatalyst for environmental remediation.

Adsorptive and photocatalytic performance of cobalt-doped ZnTiO3/Ti3C2Tx MXene nanohybrids towards tetracycline: Kinetics and mechanistic insight.

Tetracycline (TC) antibiotics are widely used in animal husbandry and can cause environmental risk due to its high ecological toxicity and persistence. In this study, cobalt doped/ZnTiO3 (ZTO)/Ti3C2Tx MXene (ZCxTM, x indicates wt% of Co loading) was synthesized and explored to remove TC by adsorption and photocatalysis under visible light irradiation. The as-prepared ZC5TM was characterized using various analytical techniques, and key operating parameters such as solution pH, background ions, and temperature were systematically investigated. Interestingly, ZC5TM (14.9mg/g) showed excellent adsorption capacity for TC, which was higher than activated carbon (7.7mg/g), ZTO (4.9mg/g), ZC3T (5.2mg/g), ZC5T (5.3mg/g), MXene (12.1mg/g), ZTOM (12.5mg/g), and ZC3TM (12.9mg/g). The pseudo-second-order kinetics and Langmuir isotherm models well explained the effect of contact time and initial concentrations on the adsorption of TC. The adsorption process was primarily through the electrostatic attraction, surface complexation, and hydrogen bonding. In addition, MXene and Co doped on ZTO served as co-catalyst and reduced recombination rate of photo-generated e--h+ pairs by the intimate interface of its heterojunction. Thus, ZC5TM was highly effective for the photocatalytic degradation of residual TC after adsorption by showing 18% TC degradation rate, compared to 8% and 9% degradation rate for ZTO and MXene, respectively. There results finally support the feasible use of ZC5TM as efficient adsorbent and photocatalyst in removal of TC in wastewater.

Shedding light on the transfer of tetracycline in forward osmosis through experimental investigation and machine learning modeling

Tetracycline in wastewater can pose adverse impacts on the environment and human health. Forward osmosis (FO) is a promising method to reject antibiotics due to its low energy demand and high rejection rate. Tetracycline rejection during FO is a complicated process. Mechanistic models have been developed to describe antibiotic rejection by the FO membrane under ideal conditions but cannot be applied to real wastewater. Herein, the effects of draw concentration, pH, and solute type on the fate of tetracycline during FO were investigated by combining experimentation, factor analysis, and artificial neural network (ANN) modeling. High draw concentrations led to high convection that favored tetracycline diffusion. Low draw pH helped reject antibiotics potentially due to the decreased tortuosity and pore size of the FO membrane. When different draw solutes were tested, both convection and electrostatic interaction exerted effects on tetracycline retention on the FO membrane surface, and steric hindrance could further affect the amount of tetracycline in the draw solution. Exploratory factor analysis (EFA) showed that tetracycline rejection was a combined result of convection, steric hindrance, and electrostatic interactions. Path analysis revealed the significant roles of initial conductivity and draw pH in tetracycline rejection. Eight representative input variables were selected from 13 observed explanatory variables using redundancy analysis (RDA), based on which an ANN was trained and successfully predicted tetracycline diffusion and transfer through the FO membrane. These results have provided practical and predictive insights in the development of FO processes for efficient treatment of pharmaceutical wastewater.

Carbon-doped flower-like Bi2WO6 decorated carbon nanosphere nanocomposites with enhanced visible light photocatalytic degradation of tetracycline

In search of a recyclable catalyst with synergistic adsorption and photocatalysis, unique composite photocatalysts of flower-like bismuth tungstate (Bi2WO6) and carbon nanospheres (CSs) were composited using a hydrothermal synthesis method (named CSs-Bi2WO6). Notably, based on the high visible light utilization and a reasonable band gap (2.53 eV), CSs-Bi2WO6 have good photocatalytic properties. For example, the composite with an optimized ratio (2% CSs-Bi2WO6) showed good adsorption and photocatalytic performance. Under simulated natural light conditions, the degradation rate of tetracycline (TC) by 2% CSs-Bi2WO6 was 84.6% in 60 min, which is nearly 25% higher than pure Bi2WO6. After five cycles, the observed barely decreased TC degradation rate of 2% CSs-Bi2WO6 confirmed the high cyclability and reproducibility of the photocatalyst. The total organic carbon estimation of the post-degradation reaction medium corresponded to 68.2% mineralization. Furthermore, we determined the photocatalytic reaction path by LC–MS, which confirmed that the composite catalyst could effectively degrade TC molecules into small molecules. It can be concluded that the catalyst has a broad application prospect in the field of wastewater treatment. Carbon-doped Bi2WO6 composite catalyst was used to degrade TC in wastewater efficiently

Enhanced photodegradation of tetracycline in wastewater and conversion of CO2 by solar light assisted ZnO/g-C3N4

Synthesized graphitic carbon nitride-based (CN) heterojunction photocatalysts are considered as a promising material for photodegradation of organic compounds and CO2 conversion. In this work, ZnO-loaded g-C3N4 (ZnO/CN) heterojunction photocatalyst was investigated for the enhanced photooxidation of tetracycline (TC) and CO2 conversion . After modification, the photocatalysts showed an improvement in the light absorption range and the photogenerated separation rate of electron/hole due to the heterojunction structure of ZnO/CN. The degradation rate of TC was found to be 92.6% within 60 min, while CO production rate was 7.68 μmol/g/h. The rate constants of TC by using ZnO/CN were 0.0812, 0.0539, 0.0336, 0.0249, and 0.0185 min−1, corresponding to the TC level of 1, 10, 30, 50, and 100 mg/L, respectively. The photodegradation rate of TC by ZnO/CN was 5 times higher than that of CN, demonstrating the advantage of heterojunction photocatalyst.The modified ZnO/CN exhibited superior degradation performance of TC and higher CO2 conversion rate than those of unmodified CN. It also exhibited high stability with 82% removal efficiency of TC at the 6th run and the CO2 conversion rate of 71% after reused 5 times.The heterojunction ZnO/CN can be utilized as an efficient material for various photocatalytic applications.

Unraveling the key driving factors involved in cometabolism enhanced aerobic degradation of tetracycline in wastewater

Cometabolism has shown great potential in increasing the engineering feasibility of microalgae-based biotechnologies for the aerobic treatment of antibiotics-polluted wastewaters. Yet, the underlying mechanisms involved in improved microalgal performance remain unknown. In this study, we incorporated transcriptomics, gene network analysis, and enzymatic activities with cometabolic pathways of tetracycline (TC) by Chlorella pyrenoidosa to identify the key driving factors. The results demonstrated that cometabolism constructed a metabolic enzymes-photosynthetic machinery to improve the electron transport chain and activities of catalytic enzymes, which resulted in subsequent 100% removal of TC. Coupling formation dynamics of the intermediates with roles of identified metabolic enzymes, degradation of TC can be induced by de/hydroxylation, de/hydrogenation, bond-cleavage, decarboxylation, and deamination. Evaluation of 18 antibiotics’ removal in reclaimed water showed cometabolism decreased the total concentrations of these antibiotics from 495.54 ng L−1 to 221.80 ng L−1. Our findings not only highlight the application potential of cometabolism in increasing engineering feasibility of microalgal degradation of antibiotics from wastewaters, but also provide the unique insights into unraveling the “black-box” of cometabolisms in aerobic biodegradation.

Comprehensive electrocatalytic degradation of tetracycline in wastewater by electrospun perovskite manganite nanoparticles supported on carbon nanofibers

Comprehensive electrocatalytic degradation of tetracycline in wastewater by electrospun perovskite manganite nanoparticles supported on carbon nanofibers

Enhanced photocatalytic H2 evolution and photodegradation of antibiotic tetracycline in wastewater by TiO2@Ti3C2

In this paper, the TiO2@Ti3C2 heterostructure was synthesized based on the hydrothermal oxidation process. The TiO2@Ti3C2 heterostructure could improve the separation and migration efficiency of photogenerated carriers, leading to enhancing the photocatalytic hydrogen evolution and photodegradation of antibiotic tetracycline (TC) in wastewater. Under optimum conditions, TiO2@Ti3C2 displayed high performance of hydrogen (H2) evolution at 2.138 mmolg−1h−1, which was 4.1 times higher than that of TiO2. Besides, the synthesized photocatalyst also can remove 90.7% TC from wastewater within 60 min. The recycling experiment demonstrated long-term stability of TiO2@Ti3C2 with more than 92% of H2 was produced and 85% of TC was removed after 3 cycles. The characterization and experiment results determined the improved photocatalytic activity of TiO2@Ti3C2 was based on excellent electronic conductivity via electron transfer carriers, slow the recombination of photogenerated carriers as well high visible light absorption range. This finding further confirmed the potential of TiO2@Ti3C2 photocatalyst for the production of H2 energy and the practical treatment of antibiotic pollutants in wastewater.

Synthetic Ilmenite (FeTiO3) Nanoparticles as a Heterogeneous Electro-Fenton Catalyst for the Degradation of Tetracycline in Wastewater

Synthetic Ilmenite (FeTiO₃) Nanoparticles as a Heterogeneous Electro-Fenton Catalyst for the Degradation of Tetracycline in Wastewater

Adsorption performance of tetracycline on NiFe layered double hydroxide hollow microspheres synthesized with silica as the template

Tetracycline (TC) has poor degradability and hepatotoxicity which will increase the burden on the aquatic environment when discharged into lakes in large quantities. LDH materials are often used as adsorbents because of their superior surface area and controllability of morphology. Herein, NiFe LDH hollow microspheres (NFHMS) were synthesized by a facile hydrothermal method. The removal of tetracycline by the as-prepared material in an aquatic environment was systematically investigated through comprehensive characterizations. The NFHMS sample presents a larger specific surface area than the two control samples, which contributes to its higher adsorption performance. The adsorption mechanisms of TC on NFHMS is mainly electrostatic adsorption. The fitting results of experimental data coincide well with pseudo-second-order and Weber-Morris models through kinetic simulation. Moreover, the Langmuir model is verified to be more suitable than the Freundlich model in elucidating molecular surface adsorption, and the maximum adsorption capacity of NFHMS obtained from the Langmuir model is 90.9 mg g−1. Higher temperature is beneficial to improve the adsorption performance, and the adsorption process is spontaneous and endothermic. The initial pH of the solution will affect the adsorption capacity, and the partial neutral condition is more favorable. In addition, NFHMS sample exhibits good stability in cyclic tests. Therefore, NFHMS material is expected to be a very promising adsorbent for treating tetracycline in wastewater.

Filling Polyoxoanions into MIL-101(Fe) for Adsorption of Organic Pollutants with Facile and Complete Visible Light Photocatalytic Decomposition.

Transition metal-substituted polyoxometalates (POMs) were filled into a metal–organic framework (MOF) to construct a series of POM@MOF composites (PMo12O40@MIL-101, PMo11VO40@MIL-101, PMo10V2O40@MIL-101). The composite materials possess ultra-high adsorption ability, especially for PMo10V2O40@MIL-101, with an adsorption capacity of 912.5 mg·g−1 for cationic antibiotic tetracycline in wastewater, much higher than that of isolated MIL-101(Fe) and the commonly used adsorption materials, such as activated carbon and graphene oxide. In particular, they can be used as efficient photocatalysts for the photodegradation of antibiotics under visible light irradiation. The complete photodegradation of the adsorbed species can induce the facile reusability of these composites for multiple cycles. This work opens an avenue to introduce POMs into an MOF matrix for the simultaneous adsorption and photodegradation of antibiotics.

Fabrication of developed porous carbon derived from bluecoke powder by microwave-assisted KOH activation for simulative organic wastewater treatment

Bluecoke powder (BC) was used as a precursor to prepare porous carbon (MKBC) by microwave-assisted KOH activation. The physical and chemical properties of MKBC were investigated by SEM, FT-IR, Raman, and its adsorption performance for simulative organic wastewater was detected by ultraviolet spectrum analyses. Results indicated that the surface morphology of BC was changed by microwave-assisted KOH activation, resulting in abundant macropores and micropore structures on MKBC. The high porosity of the developed meso- and micropore structures on MKBC enhanced the adsorption capacity, with the maximum Langmuir adsorption capacity (qm) of 307.692 mg/g. The kinetics were more consistent with the pseudo-first-order model when the methylene blue concentration was 50 mg/L and with the Elovich model as the concentration further increased (150 mg/L). Moreover, MKBC showed high affinity toward methylene blue at low concentrations, and the removal rate of methylene blue was more than 99% in less than 1 h. The regeneration and applicability results showed that MKBC had significant stability and effectiveness, and had a certain removal effect on malachite green, rhodamine B, p-nitrophenol, and tetracycline in wastewater, in which p-nitrophenol was the best. Efficient and low-cost MKBC could play an important role in the treatment of organic wastewater and provide a new value-added utilization for BC.

ZnO@Bi5O7I Heterojunction Derived from ZIF-8@BiOI for Enhanced Photocatalytic Activity under Visible Light

In the study, ZIF-8@BIOI composites were synthesized by the hydrothermal method and then calcined to acquire the ZnO@Bi5O7I composite as a novel composite for the photocatalytic deterioration of the antibiotic tetracycline (TC). The prepared ZnO@Bi5O7I composites were physically and chemically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmet–Teller (BET) surface area, UV–Vis diffuse reflectance spectroscopy (DRS), emission fluorescence spectra, transient photocurrent response, electrochemical impedance spectra and Mott–Schottky. Among the composites formed an n–n heterojunction, which increased the separation efficiency of electrons and holes and the efficiency of charge transfer. After the photocatalytic degradation test of TC, it showed that ZnO@Bi5O7I (2:1) had the best photodegradation effect with an 86.2% removal rate, which provides a new approach to the treatment of antibiotics such as TC in wastewater.

Efficient photocatalytic degradation of tetracycline under visible light by AgCl/Bi12O15Cl6/g-C3N4 with a dual electron transfer mechanism

A novel and efficient ternary composite AgCl/Bi12O15Cl6/g-C3N4 photocatalyst was prepared by co-precipitation method. The physical structure and photochemical properties of the photocatalyst were analyzed by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Ultraviolet diffuse reflectance spectroscopy (UV-DRS), Fluorescence spectroscopy (PL). The performance of the prepared photocatalysts was evaluated by performing degradation experiments of tetracycline (TC) under different conditions (doping ratio, dosage, initial concentration and initial pH of solution). Furthermore, the stability of composite was confirmed by cycling experiment. Finally, the mechanism of ternary composite AgCl/Bi12O15Cl6/g-C3N4 photocatalyst for decomposition of TC in visible light was investigated by free radical capture experiment. The photoluminescence spectra showed that the peak intensity of the AgCl/Bi12O15Cl6/g-C3N4 composite was significantly reduced compared to other materials, indicating that the photogenerated electron-hole pairs were effectively separated, which contributed to its photocatalytic activity. The composite showed higher TC degradation activity compared to g-C3N4, Bi12O15Cl6/g-C3N4 and AgCl/g-C3N4, with optimum degradation rate constants of 8.2, 2.2 and 1.6 times that of g-C3N4, Bi12O15Cl6/g-C3N4 and AgCl/g-C3N4, respectively. Furthermore, based on the free radical capture experiment, it was confirmed that the active species playing a major role in the reaction process were·O2-, followed by h+ and·OH. A double electron transfer mechanism was inferred to be formed in the AgCl/Bi12O15Cl6/g-C3N4 composite and a possible pathway for the degradation of TC was postulated. This work provides a new approach for the effective use of solar energy, as well as a new solution strategy for the degradation of TC in wastewater.