Sonocatalytic degradation of tetracycline antibiotic using zinc oxide nanostructures loaded on nano-cellulose from waste straw as nanosonocatalyst

Using Er/Cd-Codoped Bi4O5Br2 Microspheres to Enhance Antibiotic Degradation under Visible Illumination: A Combined Experimental and DFT Investigation

High levels of antibiotic accumulation and the difficulty of degradation can have serious consequences for the environment and, therefore, require urgent attention. To solve this problem, a synergistic Er and Cd ion-codoped Bi4O5Br2 photocatalyst was proposed. The degradation rate of sulfamethoxazole (SMX) by Er/Cd-Bi4O5Br2 was eight times higher than that of pure Bi4O5Br2, exceeding that of single Er-doped or Cd-doped Bi4O5Br2, which was attributed to the ability of Er/Cd-Bi4O5Br2 to generate a variety of free radicals. Experimental results and theoretical calculations suggested a possible mechanism for the improved photocatalytic degradation rate. The reduction of the band gap can facilitate the production of electron-hole pairs, which play a significant role in the production of reactive radicals. Furthermore, an optimal stabilized structure of the ErCd-Bi4O5Br2 dopant system was identified based on the formation energy formulas of different ligand configurations. These findings offer promising potential for the degradation of broad-spectrum antibiotics and provide valuable insights for the design and modification of photocatalytic materials.

Sonocatalytic degradation of tetracycline hydrochloride using SnO2 hollow-nanofiber decorated with UiO-66-NH2

In this study, a porous hollow nanofiber SnO2 was decorated with UiO-66-NH2 nanoparticles with straightforward solvothermal method and utilized for sonocatalytic degradation of tetracycline (TC) by ultrasonic irradiation (USI). The prepared materials were characterized using different techniques such as SEM, EDS, FTIR, XRD, BET, XPS, UV-DRS, EIS, and zeta potential. SnO2 PHNF/UiO-66-NH2 nanocomposite offered the highest apparent rate constant of 0.0397 min-1 which was 6.3 and 3.1 times higher than those obtained for SnO2 PHNF and UiO-66-NH2, respectively. The integration of nanocomposite components revealed the synergy factor of 1.58, which can be due to the created heterojunctions resulted in efficiently charge carriers separation and retaining high redox ability. The effects of different affecting parameters such as TC initial concentration, pH of the solution, catalyst dosage, trapping agents, and coexisting anions on the catalytic performance were examined. The inhibitory effects of anions were confirmed to be decreased in the sequence of Cl- > NO3- > SO42-, while the sonocatalytic efficiency of the nanocomposite improved considerably in the presence of humic acid and bicarbonate. Also, the excellent performance of the catalyst was preserved during six successive cycles, suggesting the high stability of the prepared catalyst. In addition, based on the scavenger analysis, the created O2·-, OH·, and holes were contributed to the TC degradation. In conclusion, the creation heterojunction is an impressive methodology for improving the sonocatalytic activity of a catalyst, and SnO2 PHNF/UiO-66-NH2 nanocomposite was introduced as a satisfactory catalyst in sonocatalytic degradation of organic contaminants.

A review on hazards and treatment methods of released antibiotics in hospitals wastewater during the COVID-19 pandemic

Drugs and related goods are widely used in order to promote public health and the quality of life. One of the most serious environmental challenges affecting public health is the ongoing presence of antibiotics in the effluents generated by pharmaceutical industries and hospitals. Antibiotics cannot be entirely removed from wastewater using the traditional wastewater treatment methods. Unmetabolized antibiotics generated by humans can be found in urban and livestock effluent. The antibiotic present in effluent contributes to issues with resistance to antibiotics and the creation of superbugs. Over the recent 2 years, the coronavirus disease 2019 pandemic has substantially boosted hospital waste volume. In this situation, a detailed literature review was conducted to highlight the harmful effects of untreated hospital waste and outline the best approaches to manage it. Approximately 50 to 70% of the emerging contaminants prevalent in the hospital wastewater can be removed using traditional treatment strategies. This paper emphasizes the numerous treatment approaches for effectively eliminating emerging contaminants and antibiotics from hospital wastewater and provides an overview of global hospital wastewater legislation and guidelines on hospital wastewater administration. Around 90% of ECs might be eliminated by biological or physical treatment techniques when used in conjunction with modern oxidation techniques. According to this research, hybrid methods are the best approach for removing antibiotics and ECs from hospital wastewater. The document outlines the many features of effective hospital waste management and might be helpful during and after the coronavirus disease 2019 outbreak, when waste creation on all hospitals throughout the globe has considerably increased.

Ultrasonic treatment of endocrine disrupting compounds, pharmaceuticals, and personal care products in water: An updated review

Pharmaceuticals, personal care products (PPCPs), and endocrine-disrupting compounds (EDCs) have seen a recent sustained increase in usage, leading to increasing discharge and accumulation in wastewater. Conventional water treatment and disinfection processes are somewhat limited in effectively addressing this micropollutant issue. Ultrasonication (US), which serves as an advanced oxidation process, is based on the principle of ultrasound irradiation, exposing water to high-frequency waves, inducing thermal decomposition of H2O while using the produced radicals to oxidize and break down dissolved contaminants. This review evaluates research over the past five years on US-based technologies for the effective degradation of EDCs and PPCPs in water and assesses various factors that can influence the removal rate: solution pH, temperature of water, presence of background common ions, natural organic matter, species that serve as promoters and scavengers, and variations in US conditions (e.g., frequency, power density, and reaction type). This review also discusses various types of carbon/non-carbon catalysts, O3 and ultraviolet processes that can further enhance the degradation efficiency of EDCs and PPCPs in combination with US processes. Furthermore, numerous types of EDCs and PPCPs and recent research trends for these organic contaminants are considered.

Synthesis of magnetic layered double hydroxide (Fe3O4@CuCr-LDH) decorated with ZIF-8 for efficient sonocatalytic degradation of tetracycline

A series of Fe3O4@CuCr-LDH hybrids decorated with different amount of ZIF-8 (FLZ, 10-40 wt%) was prepared using simple methods and characterized with different techniques. The activity of the synthesized nanocomposites was investigated in the sonocatalytic degradation of tetracycline (TC) antibiotic from wastewater. When the content of ZIF-8 in the nanocomposite structure was 20 wt%, the FLZ-20 sonocatalyst exhibited the high performance in the sonocatalytic removal of TC. At optimum conditions (0.7 g/L catalyst dosage, pH of 7, 50 mg/L initial concentration of antibiotic, and 15 min sonication time) of the sonocatalytic removal of TC approached to 91.4% under ultrasonic irradiation (USI) using FLZ-20. This efficiency was much higher than those of obtained results by Fe3O4@CuCr-LDH and pristine ZIF-8. The formed ●OH and ●O2- exhibited the major roles in the sonocatalytic TC degradation process. The excellent performance of FLZ-20 can be attributed to the heterojunctions created between composite components, which could improve the electron transfer ability and effectively separate e-/h+ pairs. In addition, FLZ-20 showed the superior reusability and stability during three successive recycling. Moreover, the facile magnetically separation of the sonocatalyst from the aqueous solution was another outstanding feature, which prevents the formation of secondary pollutants. It can be concluded that the fabrication of heterojunctions is an efficient procedure to promote the sonocatalytic acting of the catalyst.

Tetracycline degradation by dual-frequency ultrasound combined with peroxymonosulfate

Tetracycline has received a great deal of interest for the harmful effects of substance abuse on ecosystems and humanity. The effects of different processes on the degradation of tetracycline were compared, with dual-frequency ultrasound (DFUS) in combination with peroxymonosulfate (PMS) being the most effective for the tetracycline degradation. Free radical scavenging experiments showed that O2∙-,SO4∙- and •OH were the main reactive radicals in the degradation of tetracycline. According to the major intermediates of tetracycline degradation identified, three possible degradation pathways were proposed, which are of significance for translational studies of tetracycline degradation. Notably, these intermediates were found to be significantly less toxicity. The number of active bubbles in the degradation vessel was calculated using a semi-empirical formula, and a higher value of 1.44 × 108 L-1s-1 of bubbles was obtained when using dual-frequency ultrasound at 20 kHz (210 W/L) and 80 kHz (85.4 W/L). Therefore, compared to 20 kHz, although the yield of strong oxidizing substances from individual active bubbles decreased slightly, a significant increment of the number of active bubbles still resulted in a higher synergistic effect, and the combination of DFUS and PMS should be effective in promoting the generation of reactive free radicals and mass transfer processes within the degradation vessel, which provides a method for efficient removal of tetracycline from wastewater.

Research Progress on the Degradation of Organic Pollutants in Wastewater via Ultrasound/Periodate Systems: A Review

In recent years, the efficient removal of organic pollutants from wastewater has emerged as a critical area of global research interest. Against this backdrop, an array of innovative technologies for wastewater treatment has been developed. Among numerous advanced oxidation processes (AOPs), periodate (PI), an emerging oxidizing agent in AOPs, has garnered significant attention from researchers. Particularly, the integration of ultrasound (US)-activated PI systems has been recognized as an exceptionally promising approach for the synergistic degradation of organic pollutants in wastewater. In this paper, we conducted a thorough analysis of the mechanisms underlying the degradation of organic pollutants using the US/PI system. Furthermore, we comprehensively delineated the effects of ultrasonic power, periodate concentration, temperature, pH, coexisting inorganic ions, and dissolved organic matter on the removal efficiency of organic pollutants and summarized application cases of the US/PI system for the degradation of different pollutants. Finally, we also offered prospective discussions on the future trajectories of US/PI technology development.

Sonocatalytic degradation of Bisphenol A from aquatic matrices over Pd/CeO2 nanoparticles: Kinetics study, transformation products, and toxicity

In this work, different ratios of palladium - cerium oxide (Pd/CeO2) catalyst were synthesized and characterized, while their sonocatalytic activity was evaluated for the degradation of the xenobiotic Bisphenol A (BPA) from aqueous solutions. Sonocatalytic activity expressed as BPA decomposition exhibited a volcano-type behavior in relation to the Pd loading, and the 0.25Pd/CeO2 catalyst characterized by the maximum Pd dispersion and lower crystallite size demonstrated the higher activity. Using 500 mg/L of 0.25 % Pd/CeO2 increased the kinetic constant for BPA destruction by more than two times compared to sonolysis alone (20 kHz at 71 W/L). Meanwhile, the simultaneous use of ultrasound and a catalyst enhanced the efficiency by 50.1 % compared to the sum of the individual processes, resulting in 95 % BPA degradation in 60 min. The sonocatalytic degradation of BPA followed pseudo-first-order kinetics, and the apparent kinetic constant was increased with ultrasound power and catalyst loading, while the efficiency was decreased in bottled water and secondary effluent. From the experiments that were conducted using appropriate scavengers, it was revealed that the degradation mainly occurred on the bubble/liquid interface of the formed cavities, while the reactive species produced from the thermal or light excitation of the prepared semiconductor also participated in the reaction. Five first-stage and four late-stage transformation products were identified using UHPLC/TOF-MS, and a pathway for the sonocatalytic degradation of BPA was proposed. According to ECOSAR software prediction, most transformation by-products (TBPs) present lower ecotoxicity than the parent compound, although some remain toxic to the indicators chosen.

Sonocatalytic degrading antibiotics over activated carbon in cow milk

Herein, an efficient, simple and economical approach to remove antibiotics (ABX), i.e. ceftiofur hydrochloride, sulfamonomethoxine sodium (SMM), marbofloxacin and oxytetracycline by sonication with activated carbon (AC) from cow milk has been successfully implemented. The pseudo-first-order kinetics constants for the sonolytic and sonocatalytic degrading SMM are 0.036 and 0.093 min-1, respectively. The synergistic efficiency of removing ABX by using sonocatalysis reached 1.8-4.0. Hydrophobic ABX underwent faster degradation than hydrophilic ABX in sonocatalytic systems. Adding 0.5 mmol L-1 H2O2, the optimal concentration, improved the sonocatalytic degradation rates of ABX by 9.1%-28.5%. Surface area and dose of AC play crucial roles in the sonocatalysis of ABX. By sonicating 50 mL of 5.52 μmol L-1 ABX in milk at 500 kHz and 259 W with 20 mg AC for 20-60 min resulted in residual ABX concentrations ranging from 42.6 to 95.1 μg L-1, which meet the relative maximum residue limits set by European Commission.

Hydrothermal fabrication, characterization and RSM optimization of cobalt-doped zinc oxide nanoparticles for antibiotic photodegradation under visible light

Photodegradation is considered a significant method engaged for the elimination of organic pollutants from water. In this work, hydrothermal cobalt-doped zinc oxide nanoparticles (Hy-Co-ZnO NPs) loaded with 5, 10, and 15% cobalt were prepared in a hydrothermal way and were investigated as a photocatalyst for the Ciprofloxacin (CIPF) degradation under visible irradiation using LED-light. Characterization approaches such as FTIR, XRD, XPS, DRS UV-vis spectroscopy, SEM, TEM, BET, EDX and TGA were used for the investigation of the fabricated Hy-Co-ZnO NPs. The studies indicated that 10% Hy-Co-ZnO NPs was the most efficient catalyst for the CIPF photolysis compared to ZnO NPs and other Hy-Co-ZnO NPs with 5 and 15% cobalt content. Higher photocatalytic activity (> 98%) of 20 mg/L of CIPF solution was attained within 60 min. The reaction kinetics showed that the first-order model is suitable for displaying the rate of reaction and amount of CIPF elimination with R2 = 0.9883. Moreover, Central composite design (CCD) optimization of the 10% Hy-Co-ZnO NPs was also studied.

Advances in ultrasound-assisted synthesis of photocatalysts and sonophotocatalytic processes: A review

Water pollution and the global energy crisis are two significant challenges that the world is facing today. Ultrasound-assisted synthesis offers a simple, versatile, and green synthetic tool for nanostructured materials that are often unavailable by traditional synthesis. Furthermore, the integration of ultrasound and photocatalysis has recently received considerable interest due to its potential for environmental remediation as a low-cost, efficient, and environmentally friendly technique. The underlying principles and mechanisms of sonophotocatalysis, including enhanced mass transfer, improved catalyst-pollutant interaction, and reactive species production have been discussed. Various organic pollutants as dyes, pharmaceuticals, pesticides, and emerging organic pollutants are targeted based on their improved sonophotocatalytic degradation efficiency. Additionally, the important factors affecting sonophotocatalytic processes and the advantages and challenges associated with these processes are discussed. Overall, this review provides a comprehensive understanding of sono-assisted synthesis and photocatalytic degradation of organic pollutants and prospects for progress in this field.

Unraveling kinetic and synergistic effects during ultrasound-enhanced carbocatalysis for water remediation as a function of ultrasonic frequency

The ability of the ultrasound (US) combined with peroxymonosulfate (PMS), and a carbonaceous material (BC) was evaluated in the degradation of a model pollutant (acetaminophen, ACE). The US/BC/PMS system was compared with other possible systems (US, oxidation by PMS, BC adsorption, BC/PMS, US/PMS, and US/BC. The effect of the ultrasonic frequency (40, 375, and 1135 kHz) on the kinetics and synergy of the ACE removal was evaluated. In the US system, kinetics was favored at 375 kHz due to the increased production of hydroxyl radicals (HO•), but this did not improve in the US/PMS and US/BC systems. However, synergistic and antagonistic effects were observed at the low and high frequencies where the production of radicals is less efficient but there is an activation of PMS through mechanical effects. US/BC/PMS at 40 kHz was the most efficient system obtaining ∼95% ACE removal (40 μM) in the first 10 min of treatment, and high synergy (S = 10.30). This was promoted by disaggregation of the carbonaceous material, increasing the availability of catalytic sites where PMS is activated. The coexistence of free-radical and non-radical pathways was analyzed. Singlet oxygen (1O2) played the dominant role in degradation, while HO• and sulfate radicals (SO4•-), scarcely generated at low frequency, play a minimum role. Performance in hospital wastewater (HWW), urine, and seawater (SW) evidenced the competition of organic matter by BC active sites and reactive species and the removal enhancement when Cl- is present. Besides, toxicity decreased by ∼20% after treatment, being the system effective after three cycles of reuse.

Efficient sonochemical catalytic degradation of tetracycline using TiO2 fractured nanoshells

Overexposure to antibiotics originating in wastewater has profound environmental and health implications. Conventional treatment methods are not fully effective in removing certain antibiotics, such as the commonly used antibiotic, tetracycline, leading to its accumulation in water catchments. Alternative antibiotic removal strategies are garnering attention, including sonocatalytic oxidative processes. In this work, we investigated the degradation of tetracycline using a combination of TiO2 fractured nanoshells (TFNs) and an advanced sonochemical reactor design. The study encompassed an examination of multiple process parameters to understand their effects on the degradation of tetracycline. These included tetracycline adsorption on TFNs, reaction time, initial tetracycline concentration, solvent pH, acoustic pressure amplitude, number of acoustic cycles, catalyst dosage, TFNs' reusability, and the impact of adjuvants such as light and H2O2. Though TFNs adsorbed tetracycline, the addition of ultrasound was able to degrade tetracycline completely (with 100% degradation) within six minutes. Under the optimal operating conditions, the proposed sonocatalytic system consumed 80% less energy compared to the values reported in recently published sonocatalytic research. It also had the lowest CO2 footprint when compared to the other sono-/photo-based technologies. This study suggests that optimizing the reaction system and operating the reaction under low power and at a lower duty cycle are effective in achieving efficient cavitation for sonocatalytic reactions.

Impact of Polythiophene ((C4H4S)n; n = 3, 5, 7, 9) Units on the Adsorption, Reactivity, and Photodegradation Mechanism of Tetracycline by Ti-Doped Graphene/Boron Nitride (Ti@GP_BN) Nanocomposite Materials: Insights from Computational Study

This study addresses the formidable persistence of tetracycline (TC) in the environment and its adverse impact on soil, water, and microbial ecosystems. To combat this issue, an innovative approach by varying polythiophene ((C4H4S)n; n = 3, 5, 7, 9) units and the subsequent interaction with Ti-doped graphene/boron nitride (Ti@GP_BN) nanocomposites was applied as catalysts for investigating the molecular structure, adsorption, excitation analysis, and photodegradation mechanism of tetracycline within the framework of density functional theory (DFT) at the B3LYP-gd3bj/def2svp method. This study reveals a compelling correlation between the adsorption potential of the nanocomposites and their corresponding excitation behaviors, particularly notable in the fifth and seventh units of the polythiophene configuration. These units exhibit distinct excitation patterns, characterized by energy levels of 1.3406 and 924.81 nm wavelengths for the fifth unit and 1.3391 and 925.88 nm wavelengths for the seventh unit. Through exploring deeper, the examination of the exciton binding energy emerges as a pivotal factor, bolstering the outcomes derived from both UV-vis transition analysis and adsorption exploration. Notably, the calculated exciton binding energies of 0.120 and 0.103 eV for polythiophene units containing 5 and 7 segments, respectively, provide compelling confirmation of our findings. This convergence of data reinforces the integrity of our earlier analyses, enhancing our understanding of the intricate electronic and energetic interplay within these intricate systems. This study sheds light on the promising potential of the polythiophene/Ti-doped graphene/boron nitride nanocomposite as an efficient candidate for TC photodegradation, contributing to the advancement of sustainable environmental remediation strategies. This study was conducted theoretically; hence, experimental studies are needed to authenticate the use of the studied nanocomposites for degrading TC.

Ultrasound enhanced destruction of tetracycline hydrochloride with peroxydisulfate oxidation over FeS/NBC catalyst: Governing factors, strengthening mechanism and degradation pathway

In this study, FeS/N-doped biochar (NBC) derived from the co-pyrolysis of birch sawdust and Mohr's salt was applied to evaluate the efficiency of catalyzed peroxydisulfate (PDS) oxidation for tetracycline (TC) degradation. It is found that the combination of ultrasonic irradiation can distinctly enhance the removal of TC. This study investigated the effects of control factors such as PDS dose, solution pH, ultrasonic power, and frequency on TC degradation. Within the applied ultrasound intensity range, TC degradation increases with increasing frequency and power. However, excessive power can lead to a reduced efficiency. Under the optimized experimental conditions, the observed reaction kinetic constant of TC degradation increased from 0.0251 to 0.0474 min-1, with an increase of 89%. The removal ratio of TC also increased from ∼85% to ∼99% and the mineralization level from 45% to 64% within 90 min. Through the decomposition testing of PDS, reaction stoichiometric efficiency calculation, and electron paramagnetic resonance experiments, it is shown that the increase in TC degradation of the ultrasound-assisted FeS/NBC-PDS system was attributed to the increase in PDS decomposition and utilization, as well as the increase in SO4•- concentration. The radical quenching experiments showed that SO4•-, •OH, and O2•- radicals were the dominant active species in TC degradation. TC degradation pathways were speculated according to intermediates from HPLC-MS analysis. The test of simulated actual samples showed that dissolved organic matter, metal ions, and anions in waters can undercut the TC degradation in FeS/NBC-PDS system, but ultrasound can significantly reduce the negative impact of these factors.

Multidimensional applications and potential health implications of nanocomposites

This study reviews the concept, classifications, and techniques involved in the synthesis of nanocomposites. The environmental and health implications of nanoparticles and composite materials were detailed, as well as the applications of nanocomposites in water remediation, antibacterial application, and printed circuit boards. The study gave insights into the challenges of water pollution treatment and provided a broad list of nanocomposites that have been explored for water remediation. Moreover, the emergence of multi-drug resistance to many antibiotics has made current antibiotics inadequate in the treatment of disease. This has engineered the development of alternative strategies in the drug industries for the production of effective therapeutic agents, comprising nanocomposites with antibacterial agents. The new therapeutic agents known as nanoantibiotics are more efficient and have paved the way to handle the challenges of antibiotic resistance. In printed circuit boards, nanocomposites have shown promising applications because of their distinct mechanical, thermal, and electrical characteristics. The uniqueness of the write-up is that it provides a broad explanation of the concept, synthesis, application, toxicity, and harmful effects of nanocomposites. Thus, it will provide all-inclusive awareness to readers to identify research gaps and motivate researchers to synthesize novel nanocomposites for use in various fields.

Efficient Photocatalytic Degradation of Tetracycline on the MnFe2O4/BGA Composite under Visible Light

In this work, the MnFe₂O₄/BGA (boron-doped graphene aerogel) composite prepared via the solvothermal method is applied as a photocatalyst to the degradation of tetracycline in the presence of peroxymonosulfate. The composite's phase composition, morphology, valence state of elements, defect and pore structure were analyzed by XRD, SEM/TEM, XPS, Raman scattering and N₂ adsorption-desorption isotherms, respectively. Under the radiation of visible light, the experimental parameters, including the ratio of BGA to MnFe₂O₄, the dosages of MnFe₂O₄/BGA and PMS, and the initial pH and tetracycline concentration were optimized in line with the degradation of tetracycline. Under the optimized conditions, the degradation rate of tetracycline reached 92.15% within 60 min, whereas the degradation rate constant on MnFe₂O₄/BGA remained 4.1 × 10^-2 min^-1, which was 1.93 and 1.56 times of those on BGA and MnFe₂O₄, respectively. The largely enhanced photocatalytic activity of the MnFe₂O₄/BGA composite over MnFe₂O₄ and BGA could be ascribed to the formation of type I heterojunction on the interfaces of BGA and MnFe₂O₄, which leads to the efficient transfer and separation of photogenerated charge carriers. Transient photocurrent response and electrochemical impedance spectroscopy tests offered solid support to this assumption. In line with the active species trapping experiments, SO₄^•- and O₂^•- radicals are confirmed to play crucial roles in the rapid and efficient degradation of tetracycline, and accordingly, a photodegradation mechanism for the degradation of tetracycline on MnFe₂O₄/BGA is proposed.

Recent trends in the applications of sonochemical reactors as an advanced oxidation process for the remediation of microbial hazards associated with water and wastewater: A critical review

Water is one of the major sources that spread human diseases through contamination with bacteria and other pathogenic microorganisms. This review focuses on microbial hazards as they are often present in water and wastewater and cause various human diseases. Among the currently used disinfection methods, sonochemical reactors (SCRs) that produce free radicals combined with advanced oxidation processes (AOPs) have received significant attention from the scientific community. Also, this review discussed various types of cavitation reactors, such as acoustic cavitation reactors (ACRs) utilizing ultrasonic energy (UE), which had been widely employed, involving AOPs for treating contaminated waters. Besides ACRs, hydrodynamic cavitation reactors (HCRs) also effectively destroy and deactivate microorganisms to varying degrees. Cavitation is the fundamental phenomenon responsible for initiating many sonochemical reactions in liquids. Bacterial degradation occurs mainly due to the thinning of microbial membranes, local warming, and the generation of free radicals due to cavitation. Over the years, although extensive investigations have focused on the antimicrobial effects of UE (ultrasonic energy), the primary mechanism underlying the cavitation effects in the disinfection process, inactivation of microbes, and chemical reactions involved are still poorly understood. Therefore, studies under different conditions often lead to inconsistent results. This review investigates and compares other mechanisms and performances from greener and environmentally friendly sonochemical techniques to the remediation of microbial hazards associated with water and wastewater. Finally, the energy aspects, challenges, and recommendations for future perspectives have been provided.

Study on persulfate activated by Ce-modified tea waste biochar to degrade tetracycline

In this study, the Ce-modified tea residue biochar (Ce-TBC) was successfully generated and applied to the biochar/persulfate system (Ce-TBC/PDS), the mechanism of the removal of tetracycline (TC) using Ce-TBC/PDS was elaborated. Under the optimal experimental conditions (Ce-TBC = 0.8 g L^-1, PDS = 4 mM, TC = 10 mg L^-1), the removal efficiency of TC was 91.28%, and after 5 cycles, the elimination rate of Ce-TBC/PDS still reached up to 80%. The mechanism of TC removal by Ce-TBC/PDS was analyzed by scanning electron microscopy (SEM), X-ray diffractometer (XRD), Fourier infrared transform spectrometer (FT-IR), and X-ray photoelectron spectrometer (XPS) characterization, and influence factor experiments. The results showed that the introduction of CeO_x increased the oxygen vacancies on the TBC surface and promoted the interconversion between Ce³⁺ and Ce⁴⁺ for better activation of PDS and generation of active species. Free radical quenching experiments and paramagnetic resonance spectrometry (EPR) analysis showed that the non-radical pathway ¹O₂ played a dominant role in the Ce-TBC/PDS system. The present work provided an efficient means of PDS activator and recycling of tea waste.

Performance and mechanism of a novel S-scheme heterojunction sonocatalyst CuS/BaWO4 for degradation of bisphenol A by ultrasonic activation

A novel CuS/BaWO₄ heterojunction catalyst was prepared and characterized. Taking bisphenol A as the target pollutant for catalytic degradation, the sonocatalytic activity of CuS/BaWO₄ composite was evaluated, and the combination with persulfate improved the sonocatalytic degradation of bisphenol A. The results showed that CuS/BaWO₄ composite had good sonocatalytic degradation activity for bisphenol A, and the degradation rate was 70.99% ± 1.46%. After combined with persulfate, the degradation rate was further increased to 95.34% ± 0.10%, and the reaction time was relatively shortened. The results of the trapping experiment and calculated energy band positions showed that the formation of S-scheme heterojunction and the formation of hydroxyl radicals and holes were the key to the catalytic degradation of bisphenol A by CuS/BaWO₄ composite. In this study, a new CuS/BaWO₄ heterojunction sonocatalyst was synthesized. The catalyst can efficiently remove bisphenol A from the water environment and can be used as a potential solution for endocrine disruptor pollution in the water environment.

Peroxydisulfate-assisted sonocatalytic degradation of metribuzin by La-doped ZnFe layered double hydroxide

Metribuzin is an herbicide that easily contaminates ground and surface water. Herein, La-doped ZnFe layered double hydroxide (LDH) was synthesized for the first time and used for the degradation of metribuzin via ultrasonic (US) assisted peroxydisulfate (PDS) activation. The synthesized LDH had a lamellar structure, an average thickness of 26 nm, and showed mesoporous characteristics, including specific surface area 110.93 m2 g-1, pore volume 0.27 cm3 g-1, and pore diameter 9.67 nm. The degradation efficiency of the US/La-doped ZnFe LDH/PDS process (79.1 %) was much greater than those of the sole processes, and the synergy factor was calculated as 3.73. The impact of the reactive species on the sonocatalytic process was evaluated using different scavengers. After four consecutive cycles, 10.8 % loss occurred in the sonocatalytic activity of the La-doped LDH. Moreover, the efficiency of the US/La-doped LDH/PDS process was studied with respect to the degradation of metribuzin in a wastewater matrix. According to GC-MS analysis, six by-products were detected during the degradation of metribuzin. Our results indicate that the US/La-doped ZnFe LDH/PDS process has great potential for efficient degradation of metribuzin-contaminated water and wastewater.

Combined ultrasound cavitation and persulfate for the treatment of pharmaceutical wastewater

In recent years industrialization has caused magnificent leaps in the high profitable growth of pharmaceutical industries, and simultaneously given rise to environmental pollution. Pharmaceutical processes like extraction, purification, formulation, etc., generate a large volume of wastewater that contains high chemical oxygen demand (COD), biological oxygen demand, auxiliary chemicals, and different pharmaceutical substances or their metabolites in their active or inactive form. Its metabolites impart non-biodegradable toxic pollutants as a byproduct and intense color, which increases ecotoxicity into the water, thus this requires proper treatment before being discharged. This study focuses on the feasibility analysis of the utilization of ultrasound cavitation (20 kHz frequency) together with a persulfate oxidation approach for the treatment of complex pharmaceutical effluent. Process parameters like pH, amplitude intensity, oxidant dosage were optimized for COD removal applying response surface methodology-based Box-Behnken design. The optimum value observed for pH, amplitude intensity and oxidant dosage are 5, 20% and 100 mg/L respectively with 39.5% removal of COD in 60 min of fixed processing time. This study confirms that a combination of ultrasound cavitation and persulfate is a viable option for the treatment of pharmaceutical wastewater and can be used as an intensification technology in existing effluent treatment plants to achieve the highest amount of COD removal.

Recent advances and future perspective on nanocellulose-based materials in diverse water treatment applications

Over the past few years, nanocellulose and its derivatives have drawn attention as promising bio-based materials for water treatment applications due to their high surface area, high strength, and renewable, biocompatible nature. The abundance of hydroxyl functional groups on the surfaces of cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) enables a broad range of surface modifications which results in propitious nanocomposites with tunable characteristics. In this context, this review describes the continuously developing applications of nanocellulose-based materials in the areas of adsorption, catalysis, filtration, and flocculation, with a special emphasis on the removal of contaminants such as heavy metals, dyes, and pharmaceutical compounds from diverse water systems. Recent progresses in the diverse forms of application of nanocellulose adsorbents (suspension, hydrogel, aerogel, and membrane) are also highlighted. Finally, challenges and future perspectives on emerging nanocellulose-based materials and their possible industrial applications are presented and discussed.

Preparation of Ag3PO4/CoWO4 S-scheme heterojunction and study on sonocatalytic degradation of tetracycline

In this study, 0.6Ag3PO4/CoWO4 composites were synthesized by hydrothermal method. The prepared materials were systematically characterized by techniques of scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption, and UV-vis diffuse reflectance spectrum (DRS). Furthermore, the sonocatalytic degradation performance of 0.6Ag3PO4/CoWO4 composites towards tetracycline (TC) was investigated under ultrasonic radiation. The results showed that, combined with potassium persulfate (K2S2O8), the 0.6Ag3PO4/CoWO4 composites achieved a high sonocatalytic degradation efficiency of 97.89 % within 10 min, which was much better than bare Ag3PO4 or CoWO4. By measuring the electrochemical properties, it was proposed that the degradation mechanism of 0.6Ag3PO4/CoWO4 is the formation of S-scheme heterojunction, which increases the separation efficiency of electron-hole pairs (e--h+) and generates more electrons and holes, thereby enhancing the degradation activity. The scavenger experiments confirmed that hole (h+) was the primary active substance in degrading TC, and free radicals (OH) and superoxide anion radical (O2-) were auxiliary active substances. The results indicated that 0.6Ag3PO4/CoWO4 nanocomposites could be used as an efficient and reliable sonocatalyst for wastewater treatment.

Degradation of sulfadiazine by UV/Oxone: roles of reactive oxidative species and the formation of disinfection byproducts

Sulfadiazine (SDZ) is a typical persistent sulfonamide antibiotic, which has been widely detected in natural drinking water sources. The degradation of SDZ by UV/Oxone (potassium monopersulfate compound) was explored in this study. The results showed that Cl^- can effectively activate PMS to promote rapid degradation of SDZ in the Oxone process by forming chlorine in the system. Radical quenching tests suggested that radical oxidation, including HO^•, SO₄^•-, and reactive chlorine species (RCS), played an important role by UV/Oxone. It further verified that concentration and distribution of HO^•, SO₄^•-, and RCS were pH-dependent; RCS act as a major contributor at pH 6.0 and pH 7.0 to degrade SDZ in this process. The SDZ degradation rate was firstly increased and then decreased by Cl^- and HCO₃^- (0-10 mM); HA (0-10 mg L^-1) exhibited insignificant influence on SDZ degradation. The degradation pathways of SDZ during UV/Oxone and formation pathways of five disinfection byproducts during subsequent chlorination were proposed. The possible DBP precursors formed by SO₂ extrusion, hydroxylation, and chlorination of SDZ during UV/Oxone pre-oxidation.

Cellulose Structures as a Support or Template for Inorganic Nanostructures and Their Assemblies

Cellulose is the most abundant natural polymer and deserves the special attention of the scientific community because it represents a sustainable source of carbon and plays an important role as a sustainable energent for replacing crude oil, coal, and natural gas in the future. Intense research and studies over the past few decades on cellulose structures have mainly focused on cellulose as a biomass for exploitation as an alternative energent or as a reinforcing material in polymer matrices. However, studies on cellulose structures have revealed more diverse potential applications by exploiting the functionalities of cellulose such as biomedical materials, biomimetic optical materials, bio-inspired mechanically adaptive materials, selective nanostructured membranes, and as a growth template for inorganic nanostructures. This article comprehensively reviews the potential of cellulose structures as a support, biotemplate, and growing vector in the formation of various complex hybrid hierarchical inorganic nanostructures with a wide scope of applications. We focus on the preparation of inorganic nanostructures by exploiting the unique properties and performances of cellulose structures. The advantages, physicochemical properties, and chemical modifications of the cellulose structures are comparatively discussed from the aspect of materials development and processing. Finally, the perspective and potential applications of cellulose-based bioinspired hierarchical functional nanomaterials in the future are outlined.

The Emerging Role of Ultrasonic Nanotechnology for Diagnosing and Treatment of Diseases

Nanotechnology has been commonly used in a variety of applications in recent years. Nanomedicine has also gotten a lot of attention in the medical and treatment fields. Ultrasonic technology is already being used in research as a powerful tool for manufacturing nonmaterial and in the decoration of catalyst supports for energy applications and material processing. For the development of nanoparticles and the decoration of catalytic assisted powders with nanoparticles, low or high-frequency Ultrasonic are used. The Ultrasonic is frequently used in joint venture with the nanotechnology from the past few years and bring tremendous success in various diseases diagnosing and treatment. Numerous kinds of nanoparticles are fabricated with desired capabilities and targeted toward different targets. This review first highlights the Ultrasonic Treatment and processing of Nanoparticles for Pharmaceuticals. Next, we explain various nanoparticles with ultrasonic technology for different diagnosing and treatment of various diseases. Finally, we explain the challenges face by current approaches for their translation in clinics.

Ultrasound-assisted pseudohomogeneous tungstate catalyst for selective oxidation of alcohols to aldehydes

The idea of applying ultrasound (US) as a green activation method in chemical transformations, especially in catalytic alcohol oxidations, technically and ecologically appeals to chemists. In the present work, as an attempt to fulfill the idea of designing an eco-friendly system to oxidize alcoholic substrates into corresponding aldehydes, we developed multifunctional tungstate-decorated CQD base catalyst, A-CQDs/W, and examined its sonooxidation performance in presence of H₂O₂ as a green oxidant in aqua media. By comparing the catalyst performance in oxidize benzyl alcohol as a testing model to benzaldehyde (BeOH) prior and after US irradiation—trace vs 93%- the key role of ultrasonic irradiation in achieving high yield is completely appreciated. Exceptional thermal and compression condition that is created as a result of acoustic waves is in charge of unparalleled yield results in this type of activation method. The immense degree of reagent interaction in this method, ensures the maximum yield in notably low time, which in turn leads to decrease in the number of unreacted reagents and by-products. Meanwhile, the need for using toxic organic solvents and hazardous oxidants, auxiliaries and phase transfer catalyst (PTC) is completely obviated.

Bactericidal action and molecular docking studies of catalytic Cu-doped NiO composited with cellulose nanocrystals

Synthesis of Cu-doped NiO composited with cellulose nanocrystals (CNC) was carried out by co-precipitation method. The aim of this study is to investigate the catalytic, antibacterial and molecular docking studies of prepared samples. XRD patterns confirmed rhombohedral structure of synthesized nanostructures with gradual increase in crystallite size with doping. The morphology as well as interlayer spacing was evaluated with HRTEM while functional groups presence in dopant-free and doped nanostructures was confirmed using FTIR spectra. Both CNC/NiO composite and Cu-doped CNC/NiO showed higher catalytic potential compared to dopant-free NiO, while Cu-doped CNC/NiO nanostructures exhibited significant potential for use in industrial dye degradation applications. Besides this, CNC/NiO composite showed good antibacterial activity against Escherichia coli (E. coli) bacteria and its bacterial activity increased with Cu doping. Furthermore, molecular docking predictions against dihydrofolate reductase and DNA gyrase enzyme confirmed interaction of NiO NPs, CNC/NiO and Cu-doped CNC/NiO inside active pockets and showed good agreement with in vitro bactericidal activity.

Removal of Ciprofloxacin from Wastewater by Ultrasound/Electric Field/Sodium Persulfate (US/E/PS)

Ciprofloxacin (CIP), as a common antibiotic used in human clinical and livestock farming, is discharged into natural water bodies and its concentration has increased in the last years. Its stable chemical structure is difficult to remove by conventional techniques. Residual ciprofloxacin in the environment has become an emerging micropollutant that promotes the generation of resistance genes of bacteria and endangers ecosystem balance and human health. Removal of ciprofloxacin from water by the system of ultrasound/electric field/sodium persulfate (US/E/PS) was investigated. Firstly, CIP degradation affects by different oxidation methods, such as ultrasonic oxidation, electro-oxidation, and persulfate oxidation, and their four combined oxidation methods (ultrasound-activated persulfate oxidation, electro-activated persulfate oxidation, ultrasound-enhanced electro-oxidation, and ultrasound-enhanced electro-activated persulfate oxidation), on the target contaminants were compared. Secondly, the influences of parameters on the CIP degradation by an ultrasound-enhanced electro-activation-persulfate reaction system were investigated. Thirdly, the possible free radical species in the ultrasound-enhanced electro-activation-sulfate reaction system were identified and the dominant free radical species in the system were analyzed. Finally, the samples of CIP in the US/E/PS system were tested by liquid mass spectrometry, and the possible intermediate products and degradation path were speculated. The results indicate that the US/E/PS system is of great potential application value in the removal of organic pollution and environmental purification.

Enhanced solar light photocatalytic performance of Fe-ZnO in the presence of H2O2, S2O82-, and HSO5- for degradation of chlorpyrifos from agricultural wastes: Toxicities investigation

This study reported Fe doped zinc oxide (Fe-ZnO) synthesis to degrade chlorpyrifos (CPY), a highly toxic organophosphate pesticide and important sources of agricultural wastes. Fourier transform infrared, X-ray diffraction, scanning electron microscope, and energy-dispersive X-ray spectroscopic analyses showed successful formation of the Fe-ZnO with highly crystalline and amorphous nature. Water collected from agricultural wastes were treated with Fe-ZnO and the results showed 67% degradation of CPY by Fe-ZnO versus 39% by ZnO at 140 min treatment time. Detail mechanism involving reactive oxygen species production from solar light activated Fe-ZnO and their role in degradation of CPY was assessed. Use of H₂O₂, peroxydisulfate (S₂O₈^2-) and peroxymonosulfate (HSO₅^-) with Fe-ZnO under solar irradiation promoted removal of CPY. The peroxides yielded hydroxyl (OH) and sulfate radical () under solar irradiation mediated by Fe-ZnO. Effects of several parameters including concentration of pollutant and oxidants, pH, co-existing ions, and presence of natural organic matter on CPY degradation were studied. Among peroxides, HSO₅^- revealed to provide better performance. The prepared Fe-ZnO showed high reusability and greater mineralization of CPY. The GC-MS analysis showed degradation of CPY resulted into several transformation products (TPs). Toxicity analysis of CPY as well as its TPs was performed and the formation of non-toxic acetate imply greater capability of the treatment technology.

Efficient pH-universal degradation of antibiotic tetracycline via Co2P decorated Neosinocalamus affinis biochar

Considering the complexity of traditional cobalt phosphide (Co₂P) loaded biochar synthesis research on a simple and efficient synthesis method has practical significance. In this study, after phosphoric acid activation, Neosinocalamus affinis biochar (NAB) and nanoplate Co₃O₄ quickly formed a Co₂P-NAB composite material with high Co₂P crystallinity and was uniformly dispersed on the surface of NAB in a microwave reactor. Co₂P-NAB has an excellent catalytic degradation effect in the activation of peroxymonosulfate (PMS) to degrade tetracycline (TC). The optimal TC degradation efficiency was achieved with the addition of 50 mg L^-1 TC concentration, 0.2 g L^-1 catalysts, 0.406 mM PMS and pH = 6.02. In addition, according to the pseudo-first-order reaction rate constant calculation, the composite of Co₂P-NAB and PMS the synergy efficiency is 81.55 %. Compared with Co₂P-NAB (10.83 %) and PMS (7.62 %) alone, the Co₂P-NAB/PMS system has a significant promotion effect on the degradation of TC molecules. Additionally, the Co₂P-NAB/PMS system had a TC mineralization rate of 68 % in 30 min. Furthermore, after a series of characterization, detection and analysis, and influencing factor experiments, we proposed a potential mechanism for the Co₂P-NAB/PMS reaction system to degrade TC and found that singlet oxygen (¹O₂) plays an essential role in the non-radical degradation process. Finally, according to the liquid chromatography-mass spectrometry (LC-MS) detection of TC degradation intermediates, a possible degradation route was proposed. Therefore, this work uses microwave technology to present a novel and simple synthesis method for transition metal phosphides, which provides potential application value for the treatment of actual wastewater with heterogeneous catalysts.

Electrocatalytic performance of sonochemically synthesized Pt–Ni/C nanoparticles in fuel cell application

Developing high-performance electrocatalysts using simple and controllable methods is of interest to reduce the cost of polymer electrolyte membrane fuel cells. In this study, platinum is alloyed with nickel and supported on carbon (Pt–Ni/C) via an ultrasound-assisted route. The crystallite and particle sizes of the obtained nanoparticles were smaller than the commercial carbon-supported Pt nanoparticles. The sonochemically synthesized Pt–Ni/C nanoparticles exhibited superior electrocatalytic properties than the commercial Pt/C nanoparticles in the fuel cell operation. Electrochemical measurements performed with Pt–Ni/C electrocatalyst displayed excellent oxygen reduction and higher electrochemical active surface area (EASA). Optimum fuel cell performance based on peak power density using Pt–Ni/C electrocatalyst was observed as 0.28 W/cm2 at 0.39 V.

Strong Structural and Electronic Binding of Bovine Serum Albumin to ZnO via Specific Amino Acid Residues and Zinc Atoms

ZnO biointerfaces with serum albumin have attracted noticeable attention due to the increasing interest in developing ZnO-based materials for biomedical applications. ZnO surface morphology and chemistry are expected to play a critical role on the structural, optical, and electronic properties of albumin-ZnO complexes. Yet there are still large gaps in the understanding of these biological interfaces. Herein we comprehensively elucidate the interactions at such interfaces by using atomic force microscopy and nanoshaving experiments to determine roughness, thickness, and adhesion properties of BSA layers adsorbed on the most typical polar and non-polar ZnO single-crystal facets. These experiments are corroborated by force field (FF) and density-functional tight-binding (DFTB) calculations on ZnO-BSA interfaces. We show that BSA adsorbs on all the studied ZnO surfaces while interactions of BSA with ZnO are found to be considerably affected by the atomic surface structure of ZnO. BSA layers on the ( 000 1 ‾ ) surface have the highest roughness and thickness, hinting at a specific upright BSA arrangement. BSA layers on ( 10 1 ‾ 0 ) surface have the strongest binding, which is well correlated with DFTB simulations showing atomic rearrangement and bonding between specific amino acids (AAs) and ZnO. Besides the structural properties, the ZnO interaction with these AAs also controls the charge transfer and HOMO-LUMO energy positions in the BSA-ZnO complexes. This ZnO facet-specific protein binding and related structural and electronic effects can be useful for improving the design and functionality of ZnO-based materials and devices.

Singlet oxygen-dominated activation of peroxymonosulfate by passion fruit shell derived biochar for catalytic degradation of tetracycline through a non-radical oxidation pathway

Waste-derived biochar has been emerged as promising catalysts to activate peroxymonosulfate (PMS) for the degradation of organic contaminants. Herein, passion fruit shell derived biochar (PFSC) was prepared by a one-pot pyrolysis method and used as a metal-free catalyst to activate PMS for the degradation of tetracycline hydrochloride (TC). The batch experiments indicated that the pyrolysis temperature could influence the efficiency of PFSC for the activation of PMS. In the PFSC-900 (prepared at 900 °C)/PMS system, the degradation rate of TC can reach 90.91%. The quenching test and electron paramagnetic resonance spectra revealed that the high catalytic performance of PFSC-900/PMS system was mainly attributed to the non-free radical reaction pathway containing a carbon bridge, and the TC degradation was controlled primarily by singlet oxygen-mediated oxidation. Moreover, the carboxyl group of ketones and the graphite-N atoms on PFSC-900 are the possible active sites of the non-free radical pathway including direct electron transfer or the formation of O₂^•-/¹O₂. This study not only shows a new type of biochar as an efficient catalyst for PMS activation but also provides a way of value-added reuse of passion fruit shell.

Degradation of amoxicillin with sono, photo, and sonophotocatalytic oxidation under low-frequency ultrasound and visible light

The presence of pharmaceutically active compounds in aquatic bodies is a global concern, and suitable treatment technologies are required. In this study, the efficacy of photocatalytic, sonocatalytic, and sonophotocatalytic oxidation processes for the degradation of amoxicillin (AMX) was investigated using visible light with N doped TiO₂ (N-TiO₂) nanoparticles as the catalyst and low-frequency ultrasound in a novel multifrequency reactor. The influence of different operational parameters on the extent of AMX degradation was studied. Sonophotocatalytic oxidation was found more efficient for AMX degradation when compared to photocatalysis or sonocatalysis alone, and may be due to the reduced bandgap of the catalyst, enhanced cavitation effect due to the presence of the solid catalyst, and improved mass transfer of pollutants. AMX degradation during sono, photo, and sonophotocatalytic oxidation processes was in good agreement with pseudo-first-order kinetics. Empirical kinetic models were also developed using multiple linear regression for predicting the degradation efficiency accounting for the operational parameters. Scavenger experiments suggested that ^•OH radicals largely contributed to AMX degradation, and a plausible mechanism for degradation was proposed. Further, possible degradation pathways for all three treatment processes are also proposed after identifying the degradation products.

Comparison of the Efficiency of Ultraviolet/Zinc Oxide (UV/ZnO) and Ozone/Zinc Oxide (O3/ZnO) Techniques as Advanced Oxidation Processes in the Removal of Trimethoprim from Aqueous Solutions

Nowadays, advanced oxidation processes, particularly photocatalyst process and catalytic ozonation by ZnO nanoparticles, are the most efficient method of eliminating pharmaceuticals. The purpose of this study was to compare the efficiency of ultraviolet/zinc oxide (UV/ZnO) and ozone/zinc oxide (O3/ZnO) techniques as advanced oxidation processes in the removal of trimethoprim (TMP) from aqueous solutions. The process consisted of 0.6 g/L of ozone (O3), pH = 7.5 ± 0.5, TMP with a concentration of 0.5–5 mg/L, ZnO with a dose of 50–500 mg/L, 5–30 min reaction time, and 30–180 min contact time with UV radiation (6 W, 256 nm) in a continuous reactor. The high removal efficiency was achieved after 25 minutes when ZnO is used in 1 mg/L TMP under an operational condition at pH 7.5. When the concentration of the pollutant increased from 0.5 to 1, the average removal efficiency increased from 78% to 94%, and then, it remained almost constant. An increase in the reaction time from 5 to 25 minutes will cause the average elimination to increase from 84% to 94%. The results showed that the efficiency of O3/ZnO process in the removal of TMP was 94%, while the removal efficiency of UV/ZnO process was 91%. The findings exhibited that the kinetic study followed the second-order kinetics, both processes. With regard to the results, the photocatalyst process and catalytic ozonation by ZnO nanoparticles can make acceptable levels for an efficient posttreatment. Finally, this combined system is proven to be a technically effective method for treating antibiotic contaminants.